Xavier Bertrand - Academia.edu (original) (raw)

Papers by Xavier Bertrand

Research paper thumbnail of Epidemiology and risk factors of Staphylococcus aureus CC398 bone and joint infections

BMC Infectious Diseases, May 29, 2020

Research paper thumbnail of Genome-based typing reveals rare events of patient contamination with Pseudomonas aeruginosa from other patients and sink traps in a medical intensive care unit

Background We used genome-based typing data with the aim of identifying the routes of acquisition... more Background We used genome-based typing data with the aim of identifying the routes of acquisition of Pseudomonas aeruginosa (PA) by patients hospitalized in a medical intensive care unit (MICU) over a long period in a non-epidemic context. Methods This monocentric prospective study took place over 10 months in 2019 in a 15-bed MICU that applies standard precautions of hygiene. Lockable sink traps installed at all water points of use were bleach disinfected twice a week. We sampled all sink traps weekly to collect 404 PA environmental isolates and collected all PA isolates (n = 115) colonizing or infecting patients (n = 65). All isolates had their phenotypic resistance profile determined and their genome sequenced, from which we identified resistance determinants and assessed the population structure of the collection at the nucleotide level to identify events of PA transmission. Results All sink traps were positive for PA, each sink trap being colonized for several months by one or ...

Research paper thumbnail of The rise and the fall of aPseudomonas aeruginosaepidemic lineage in a hospital

The biological features that allow a pathogen to survive in the hospital environment are mostly u... more The biological features that allow a pathogen to survive in the hospital environment are mostly unknown. The extinction of bacterial epidemics in hospitals is mostly attributed to changes in medical practice, including infection control, but the role of bacterial adaptation has never been documented. We analyzed a collection ofPseudomonas aeruginosaisolates belonging to the Besançon Epidemic Strain (BES), responsible for a 12-year nosocomial outbreak, using a genotype-to-phenotype approach. Bayesian analysis estimated the emergence of the clone in the hospital five years before its opening, during the creation of its water distribution network made of copper. BES survived better than the reference strains PAO1 and PA14 in a copper solution due to a genomic island containing 13 metal-resistance genes and was specifically able to proliferate in the ubiquitous amoebaVermamoeba vermiformis. Mutations affecting amino-acid metabolism, antibiotic resistance, lipopolysaccharide biosynthesis...

Research paper thumbnail of Occurrence and ecological determinants of the contamination of floodplain wetlands with Klebsiella pneumoniae and pathogenic or antibiotic-resistant Escherichia coli

FEMS Microbiology Ecology, 2019

The survival and multiplication of human pathogenic and antibiotic-resistant bacteria in ecosyste... more The survival and multiplication of human pathogenic and antibiotic-resistant bacteria in ecosystems is of increasing concern but has been little explored. Wetlands can be contaminated by water fluxes from rivers and may present environmental conditions leading to bacterial survival and multiplication. To test this hypothesis, we sampled 16 wetlands located along three rivers of the Jura Massif, France. The bacterial contamination of the wetland and river waters was measured monthly over a one-year cycle together with the water physico-chemical characteristics. We assessed the abundance of three pathogenic species: Escherichia coli,Klebsiella pneumoniaeand Pseudomonas aeruginosa. The concentrations of E. coli producing extended-spectrum β-lactamase (ESBL E. coli) or belonging to the phylogenetic group B2 (E. coli B2–more pathogenic) were also measured. We found that rivers carried total E. coli, ESBL E. coli, and K. pneumoniae to wetlands. ESBL E. coli poorly survived in wetlands, wh...

Research paper thumbnail of Contamination of a hospital plumbing system by persister cells of a copper-tolerant high-risk clone of Pseudomonas aeruginosa

Water Research, 2019

Background. Pseudomonas aeruginosa (PA) is an important opportunistic pathogen that thrives best ... more Background. Pseudomonas aeruginosa (PA) is an important opportunistic pathogen that thrives best in the distal elements of plumbing and waste-water systems. Although nosocomial outbreaks of PA have been associated with water sources, the role of the plumbing system of healthcare premises as a reservoir for this pathogen is still unclear. Materials and methods. We collected water samples from 12 technical areas, distant from any medical activity, in a teaching hospital in France once a week for 11 weeks. We used a method that resuscitates persister cells because of the nutrient-poor conditions and the presence of inhibitors (e.g. chlorine and copper ions). Briefly, water was sampled in sterile bottles containing 100 µM of the copper-ion chelating agent diethyldithiocarbamate (DDTC). A portion of the samples was immediately filtered through 0.45-µm membranes, deposited on R2A agar plates, and incubated seven days at 22°C (following European recommendations). The remaining water was incubated 14 days at 22°C and then filtered and cultured on R2A, blood-, or cetrimide-containing agar plates. PA isolates were identified by MS MALDI-TOF, genotyped by PFGE and WGS, and tested for survival in a 150 µg/L copper (II) sulphate solution. Results. Although the 12 water sampling points always tested negative with the recommended method, 67% were positive at least once for PA with the adapted method (i.e. with DDTC). The 14 PA persister isolates found throughout the plumbing system were clonal and belong to the high-risk clone ST308. Their genome harbours a 37-kb genomic island (GI-7) containing 13 genes linked to copper resistance. ST308 survived better in the copper solution than comparators that did not harbour GI-7 (P. aeruginosa strains PAO1, PA14, and ST235). The deletion of GI-7 in ST308 abrogated its tolerance to copper. The GI-7 nucleotide sequence shares 98% and 72% identity with sequences from the environmental 3 species Pseudomonas putida and the phytopathogenic species Pseudomonas syringae, respectively. Conclusion. We report the contamination of the plumbing system of a healthcare premises by persister cells of the high-risk clone P. aeruginosa ST308. New recommendations for the monitoring of water contamination should consider persister cells. The genomic island GI-7, which confers tolerance to copper, probably originates from Pseudomonas species found in copper-contaminated soils and plants. Agricultural practices may have an unexpected consequence, allowing copper-tolerant pathogens to survive in the hospital environment and contaminate fragile patients.

Research paper thumbnail of A nonlinear time-series analysis approach to identify thresholds in associations between population antibiotic use and rates of resistance

Nature Microbiology, 2019

Balancing access to antibiotics with control of antibiotic resistance is a global public health p... more Balancing access to antibiotics with control of antibiotic resistance is a global public health priority. Currently, antibiotic stewardship is informed by a 'use it and lose it' principle, in which population antibiotic use is linearly related to resistance rates. However, theoretical and mathematical models suggest use-resistance relationships are non-linear. One explanation is that resistance genes are commonly associated with 'fitness costs', impairing pathogen replication or transmissibility. Therefore, resistant genes and pathogens may only gain a survival advantage where antibiotic selection pressures exceed critical thresholds. These thresholds may provide quantitative targets for stewardship: optimising control of resistance while avoiding over-restriction of antibiotics. We evaluated the generalisability of a nonlinear time-series analysis approach for identifying thresholds using historical prescribing and microbiological data from five populations in Europe. We identified minimum thresholds in temporal relationships between use of selected antibiotics and rates of carbapenem-resistant Acinetobacter baumannii (in Hungary), extended spectrum β-lactamase producing Escherichia coli (Spain), cefepime-resistant Escherichia coli (Spain), gentamicin-resistant Pseudomonas aeruginosa (France), and methicillin-resistant Staphylococcus aureus (Northern Ireland) in different epidemiological phases. Using routinely generated data, our approach can identify context-specific quantitative targets for rationalising population antibiotic use and controlling resistance. Prospective intervention studies restricting antibiotic consumption are needed to validate thresholds.

Research paper thumbnail of Impact of a long-term antibiotic stewardship program targeting fluoroquinolones in a French local hospital

Médecine et Maladies Infectieuses, 2019

Introduction. Fluoroquinolones (FQs) are major antibiotics but their wide use in hospital and com... more Introduction. Fluoroquinolones (FQs) are major antibiotics but their wide use in hospital and community settings has led to an increased bacterial resistance against this antibiotic class. We aimed to assess the efficiency of an antibiotic stewardship program targeting FQs in a local hospital, and its impact on bacterial resistance. Methods. This observational study was conducted in the local hospital of Morteau (Franche-Comté region, East of France). The hospital has 166 beds with health and medico-social sectors and a medical home affiliated with the facility. Local guidelines on empirical treatment regimens was released in 2007 aiming to reduce the use of FQs, especially for urinary tract infections. The following monitoring indicators were assessed: total consumption of antibiotics and of FQs (DDD/1,000 hospital patient-days), and resistance to nalidixic acid among Escherichia coli strains. Changes in the number of FQ packs sold in a community pharmacy were also recorded. Results. The FQ consumption decreased by 85.6% between 2006 and 2015 (from 41.1 to 5.9 DDD/1,000 patient-days). The resistance to nalidixic acid among E. coli strains substantially decreased after remaining steady until 2011 (-57.2% between 2007 and 2015). The number of norfloxacin packs sold in the assessed community pharmacy decreased by 88%. Conclusion. Setting up an antibiotic stewardship program in a local hospital can lead to a substantial reduction in FQ use and in E. coli resistance to FQs. It may also have a positive impact on community prescriptions. RÉSUMÉ Introduction. Les fluoroquinolones (FQ) sont des antibiotiques majeurs dont la large utilisation, à l'hôpital comme en ville, a entraîné une augmentation de la résistance bactérienne contre cette classe. Notre objectif était d'évaluer l'efficacité d'une politique de bon usage des antibiotiques ciblant les FQ et d'évaluer son impact sur la résistance bactérienne. Méthodes. Étude observationnelle au centre hospitalier de Morteau (Franche-Comté), comportant des lits en secteurs sanitaire et médico-social (166 lits au total) et une maison médicale attachée à la structure. Un guide local de prescription probabiliste des antibiotiques, axé sur l'épargne des FQ (notamment dans le traitement des infections urinaires) a été diffusé en 2007. Le suivi des consommations et de la résistance était fondé sur des indicateurs (DDJ/1 000 journées d'hospitalisation et pourcentage de résistance à l'acide nalidixique chez Escherichia coli). L'évolution du nombre de boîtes de FQ vendues dans une pharmacie de la ville a été recueillie.

Research paper thumbnail of Higher third-generation cephalosporin prescription proportion is associated with lower probability of reducing carbapenem use: a nationwide retrospective study

Antimicrobial resistance and infection control, 2018

The ongoing extended spectrum β-lactamase-producing (ESBL-PE) pandemic has led to an increasing c... more The ongoing extended spectrum β-lactamase-producing (ESBL-PE) pandemic has led to an increasing carbapenem use, requiring release of guidelines for carbapenem usage in France in late 2010. We sought to determine factors associated with changes in carbapenem use in intensive care units (ICUs), medical and surgical wards between 2009 and 2013. This ward-level multicentre retrospective study was based on data from French antibiotic and multidrug-resistant bacteria surveillance networks in healthcare facilities. Antibiotic use was expressed in defined daily doses per 1000 patient-days. Factors associated with the reduction in carbapenem use (yes/no) over the study period were determined from random-effects logistic regression model (493 wards nested within 259 healthcare facilities): ward characteristics (type, size…), ward antibiotic use (initial antibiotic use [i.e., consumption of a given antibiotic in 2009], initial antibiotic prescribing profile [i.e., proportion of a given antibio...

Research paper thumbnail of The health and economic burden of bloodstream infections caused by antimicrobial-susceptible and non-susceptible Enterobacteriaceae and Staphylococcus aureus in European hospitals, 2010 and 2011: a multicentre retrospective cohort study

Euro surveillance : bulletin Européen sur les maladies transmissibles = European communicable disease bulletin, Jan 18, 2016

We performed a multicentre retrospective cohort study including 606,649 acute inpatient episodes ... more We performed a multicentre retrospective cohort study including 606,649 acute inpatient episodes at 10 European hospitals in 2010 and 2011 to estimate the impact of antimicrobial resistance on hospital mortality, excess length of stay (LOS) and cost. Bloodstream infections (BSI) caused by third-generation cephalosporin-resistant Enterobacteriaceae (3GCRE), meticillin-susceptible (MSSA) and -resistant Staphylococcus aureus (MRSA) increased the daily risk of hospital death (adjusted hazard ratio (HR) = 1.80; 95% confidence interval (CI): 1.34-2.42, HR = 1.81; 95% CI: 1.49-2.20 and HR = 2.42; 95% CI: 1.66-3.51, respectively) and prolonged LOS (9.3 days; 95% CI: 9.2-9.4, 11.5 days; 95% CI: 11.5-11.6 and 13.3 days; 95% CI: 13.2-13.4, respectively). BSI with third-generation cephalosporin-susceptible Enterobacteriaceae (3GCSE) significantly increased LOS (5.9 days; 95% CI: 5.8-5.9) but not hazard of death (1.16; 95% CI: 0.98-1.36). 3GCRE significantly increased the hazard of death (1.63; ...

Research paper thumbnail of Marked increase in incidence for bloodstream infections due to Escherichia coli, a side effect of previous antibiotic therapy in the elderly

Frontiers in Microbiology, 2015

We conducted a survey including 3334 bloodstream infections (BSIs) due to E.coli diagnosed in 200... more We conducted a survey including 3334 bloodstream infections (BSIs) due to E.coli diagnosed in 2005-2014 at a stable cohort of hospitals. Marked increases in incidence were observed for community-acquired (CA) BSIs in patients aged >75 years, CA-BSIs of digestive origin in patients aged 60-74 years, healthcare-associated BSIs, and BSIs associated with ESBL (extended-spectrum B-lactamase)-producing E. coli (ESBLEc). Using MLST, we studied the genetic diversity of 412 BSI isolates recovered during the 2014 survey: 7 major sequence type complexes (STCs) were revealed in phylogenetic group B2, 3 in group A/B1 and 2 in group D. Among the 31 ESBLEc isolates, 1/3 belonged to STC 131. We searched for possible associations between clonal groups, clinical determinants and characteristics of BSIs: isolates from groups B2 (except STC 131) and D were susceptible to antibiotics and associated with BSIs of urinary origin in patients <60 years. STC 131 and group A/B1 isolates were multi-drug resistant and associated with CA-BSIs of digestive origin in patients aged 60-74 with a recent history of antibiotic treatment. STC 131 isolates were associated with HCA-BSIs in patients with recent/present hospitalization in a long-stay unit. We provide a unique population-based picture of the epidemiology of E. coli BSI. The aging nature of the population led to an increase in the number of cases caused by the B2 and D isolates generally implicated in BSIs. In addition, the association of a trend toward increasing rates of gut colonization with multi drug-resistant isolates revealed by the rise in the incidence of BSIs of digestive origin caused by STC 131 and A/B1 (STCs 10, 23, and 155) isolates, and a significant increase in the frequency of BSIs in elderly patients with recent antibiotic treatment suggested that antibiotic use may have contributed to the growing incidence of BSI.

Research paper thumbnail of Bacterial contamination of the hospital environment during wound dressing change | Contamination bactérienne de l'environnement hospitalier lors du changement de pansements des plaies chroniques

ABSTRACT Introduction L’environnement inerte hospitalier joue un rôle dans la transmission croisé... more ABSTRACT Introduction L’environnement inerte hospitalier joue un rôle dans la transmission croisée des bactéries multirésistantes. L’objectif de l’étude était de déterminer le taux de contamination bactérienne de l’environnement lors de la réfection des pansements de plaies chroniques en fonction de la nature des espèces colonisant la plaie. L’hypothèse était que les plaies colonisées avec perte de substance entraînaient une contamination de l’environnement plus importante que les plaies non colonisées. Patients et méthodes De juillet 2010 à mai 2011, des prélèvements d’environnement (air et surfaces) ont été réalisés dans les chambres des patients porteurs de plaies colonisées (cas, n = 9) lors et hors réfection de pansements. Ont été dénombrés : Staphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter baumannii et entérobactéries. La contamination bactérienne observée a été comparée à celle correspondant à des patients porteurs de plaies non colonisées (témoins, n = 15). Résultats L’environnement était fréquemment contaminé lors de la réfection de pansements : 38 % des séries de prélèvements étaient positives. La fréquence de contamination était moins élevée pour les cas hors réfection de pansement (14,3 %) et pour les témoins (3,8 %). L’espèce S. aureus était la plus fréquemment isolée. Discussion Les résultats observés plaident en faveur de mesures déjà largement recommandées : port de masques par les soignants pour la réalisation des soins de plaies et désinfection des mains après contact avec l’environnement du patient. Mais, d’autres mesures méritent d’être proposées, notamment la réalisation du bionettoyage de la chambre avant et après la réfection de pansement sur plaies colonisées. Niveau de preuve Niveau III. Étude prospective cas-témoin.

Research paper thumbnail of Clonal Complex 398 Methicillin Susceptible Staphylococcus aureus: A Frequent Unspecialized Human Pathogen with Specific Phenotypic and Genotypic Characteristics

PLoS ONE, 2013

Clonal complex 398 livestok-associated-MRSA (CC398 LA-MRSA) clone is described as a major animal ... more Clonal complex 398 livestok-associated-MRSA (CC398 LA-MRSA) clone is described as a major animal pathogen that can also colonize and infect humans. CC398 methicillin susceptible Staphylococcus aureus (CC398 MSSA) is less described. We identified 126 CC398 MSSA strains of human origin within 6380 S. aureus isolates gathered between 2009 and 2011, from the French National Reference Centre for Staphylococci. They were characterized using antimicrobial susceptibility testing, spa typing, DNA microarrays (Identibac S. aureus Genotyping H, Alere), CC398-specific sequence PCR, ermT (encoding macrolides résistance) PCR. Fifty-three CC398 LA-MRSA collected from French pigs and veal were used as comparators, and phylogenetic relations between human CC398 MSSA and animal CC398 MRSA populations were explored on the basis of spa-typing and DNA microarrays. CC398 MSSA were able to induce a large spectrum of infections (especially skin, bloodstream, and pneumonias). The prevalence rate of this clone was high in MSSA population, i.e., 24.7% in a local prospective study on nasal colonization, and 7.5% in a national prospective study on infective endocarditis. CC398 MSSA isolates were frequently (89%) erythromycin resistant, due to the presence of the ermT gene, a gene not detected in erythromycin resistant CC398 LA-MRSA strains. Expression of staphylococcal complement inhibitor (scn) and the chemotaxis inhibitory protein (chp), was also specific to this population. The CC398 MRSA signature included also a panel of antibiotic resistance genes, especially a type IV or V cassette mec and tetM. CC398 MSSA and CC398 LA-MRSA populations were closely related based on spa-typing and DNA microarrays, with the MRSA strains forming the most derived lineage in phylogenic trees. Both MSSA and MRSA populations may come from common ancestors, which would have evolved in the settings of different selective pressures, explaining the acquisition of ermT, chp and scn for MSSA, and antibiotic resistance genes for MRSA.

Research paper thumbnail of Methicillin-Susceptible ST398 Staphylococcus aureus Responsible for Bloodstream Infections: An Emerging Human-Adapted Subclone?

PLoS ONE, 2011

for the Bloodstream Infection Study Group of the Ré seau des Hygié nistes du Centre (RHC)

Research paper thumbnail of Tracking Down Antibiotic-Resistant Pseudomonas aeruginosa Isolates in a Wastewater Network

PLoS ONE, 2012

The Pseudomonas aeruginosa-containing wastewater released by hospitals is treated by wastewater t... more The Pseudomonas aeruginosa-containing wastewater released by hospitals is treated by wastewater treatment plants (WWTPs), generating sludge, which is used as a fertilizer, and effluent, which is discharged into rivers. We evaluated the risk of dissemination of antibiotic-resistant P. aeruginosa (AR-PA) from the hospital to the environment via the wastewater network. Over a 10-week period, we sampled weekly 11 points (hospital and urban wastewater, untreated and treated water, sludge) of the wastewater network and the river upstream and downstream of the WWTP of a city in eastern France. We quantified the P. aeruginosa load by colony counting. We determined the susceptibility to 16 antibiotics of 225 isolates, which we sorted into three categories (wild-type, antibiotic-resistant and multidrug-resistant). Extended-spectrum blactamases (ESBLs) and metallo-b-lactamases (MBLs) were identified by gene sequencing. All non-wild-type isolates (n = 56) and a similar number of wild-type isolates (n = 54) were genotyped by pulsed-field gel electrophoresis and multilocus sequence typing. Almost all the samples (105/110, 95.5%) contained P. aeruginosa, with high loads in hospital wastewater and sludge ($3610 6 CFU/l or/kg). Most of the multidrug-resistant isolates belonged to ST235, CC111 and ST395. They were found in hospital wastewater and some produced ESBLs such as PER-1 and MBLs such as IMP-29. The WWTP greatly reduced P. aeruginosa counts in effluent, but the P. aeruginosa load in the river was nonetheless higher downstream than upstream from the WWTP. We conclude that the antibiotic-resistant P. aeruginosa released by hospitals is found in the water downstream from the WWTP and in sludge, constituting a potential risk of environmental contamination.

Research paper thumbnail of Usefulness of antimicrobial resistance pattern for detecting PVL- or TSST-1-producing meticillin-resistant Staphylococcus aureus in a French university hospital

Journal of Medical Microbiology, 2009

Several recent reports have suggested that community-associated meticillin-resistant Staphylococc... more Several recent reports have suggested that community-associated meticillin-resistant Staphylococcus aureus (MRSA) clones, particularly those harbouring genes for Panton–Valentine leukocidin (PVL) or toxic shock syndrome toxin 1 (TSST-1), are increasingly responsible for infections in hospitals. Here, a retrospective study was carried out to investigate whether antimicrobial resistance patterns could be used to detect these pathogens in a French university hospital. Isolates were characterized by antimicrobial susceptibility testing, PCR profiling (PVL genes and tst), PFGE typing and multilocus sequence typing. Demographic and clinical data were collected from all patients. For PVL-positive MRSA, the typical antimicrobial resistance pattern (susceptible to fluoroquinolones, non-susceptible to fusidic acid, kanamycin resistant and susceptible to gentamicin and tobramycin) had a sensitivity of 77.8 % and a positive predictive value (PPV) of 100 %. For tst-positive MRSA, the antimicrobi...

Research paper thumbnail of Antibiotics involved in the occurrence of antibiotic-resistant bacteria: a nationwide multilevel study suggests differences within antibiotic classes

Journal of Antimicrobial Chemotherapy, 2012

To identify the antibiotics potentially the most involved in the occurrence of antibiotic-resista... more To identify the antibiotics potentially the most involved in the occurrence of antibiotic-resistant bacteria from an ecological perspective in French healthcare facilities (HCFs). Methods: This study was based on data from the French antimicrobial surveillance network (ATB-RAISIN, 2007-09). Antibiotics were expressed in defined daily doses per 1000 patient-days. Antibiotic-resistant bacteria were considered as count data adjusted for patient-days. These were third-generation cephalosporin (3GC)and ciprofloxacin-resistant Escherichia coli, cefotaxime-resistant Enterobacter cloacae, methicillin-resistant Staphylococcus aureus and ceftazidime-, imipenem-and ciprofloxacin-resistant Pseudomonas aeruginosa. Three-level negative binomial regression models were built to take into account the hierarchical structure of data: level 1, repeated measures each year (count outcome, time, antibiotics); level 2, HCFs (type and size); and level 3, regions (geographical area). Results: A total of 701 HCFs from 20 French regions and up to 1339 HCF-years were analysed. The use of ceftriaxone, but not of cefotaxime, was positively correlated with incidence rates of 3GC-and ciprofloxacin-resistant E. coli. In contrast, both 3GCs were positively correlated with the incidence rate of cefotaxime-resistant E. cloacae. Higher levels of use of ciprofloxacin and/or ofloxacin, but not of levofloxacin, were associated with higher incidence rates of 3GC-and ciprofloxacin-resistant E. coli, cefotaxime-resistant E. cloacae, methicillin-resistant S. aureus and ceftazidime-and ciprofloxacin-resistant P. aeruginosa. Conclusions: Our study suggests differences within antibiotic classes in promoting antibiotic resistance. We identified ceftriaxone, ciprofloxacin and ofloxacin as priority targets in public health strategies designed to reduce antibiotic use and antibiotic-resistant bacteria in French HCFs.

Research paper thumbnail of Antibiotic susceptibility and genotypic characterization of Haemophilus influenzae strains isolated from nasopharyngeal specimens from children in day-care centers in eastern France

Clinical Microbiology and Infection, 2000

Objective To determine the overall carriage rate for Haemophilus in£uenzae in young children in d... more Objective To determine the overall carriage rate for Haemophilus in£uenzae in young children in day-care centers, the frequency of resistance to various classes of antibiotic, and the clonal relationship between isolates of the various resistant phenotypes. Methods Nasopharyngeal (NP) specimens were obtained and cultured on chocolate agar with bacitracin. Antibiotic susceptibility testing and serotyping were performed for all isolates.The genetic polymorphism of ampicillin-susceptible and b-lactamase-producing isolates was studied by pulsed-¢eld gel electrophoresis using SmaI. Results Of the 596 NP secretion cultures, 152 (25.5%) were positive for H. in£uenzae. Sixty-four (42.1%) isolates produced b-lactamase and two (1.3%) were ampicillin resistant but did not produce b-lactamase. We were unable to serotype 150 isolates; one isolate belonged to capsular serotype e and one to serotype f. Forty-six major DNA patterns were identi¢ed among 76 randomized isolates. b-lactamase producing isolates more frequently showed EP than ampicillin-susceptible isolates P < 10 À4 .The frequency of isolates with EP was signi¢cantly lower in day-care centers attended by less than 20 children than in those attended by more than 20 children (P 0.020). Conclusions Resistance due to b-lactamase production has disseminated in some day-care centers, mostly by person-to-person spread but also via the possible conjugal transfer of large plasmids between strains.The size of day-care centers may a¡ect the risk of transmission.

Research paper thumbnail of Susceptibility of Escherichia coli to the amoxycillin-clavulanate combination: which recommendations should be used to provide relevant information to clinicians?

Clinical Microbiology and Infection, 2005

Chlamydia trachomatis has been recognised as a major bacterial sexually transmitted disease (STD)... more Chlamydia trachomatis has been recognised as a major bacterial sexually transmitted disease (STD) in north America and western Europe [1]. The prevalence of infection for men in STD settings is 15-20%, with a corresponding figure for women

Research paper thumbnail of Clinical and molecular epidemiology of chromosome-mediated resistance to third-generation cephalosporins in Enterobacter isolates in eastern France

Clinical Microbiology and Infection, 2000

Objective To determine both the prevalence of group I b-lactamase-related resistance and the clin... more Objective To determine both the prevalence of group I b-lactamase-related resistance and the clinical setting in which resistance to expanded-spectrum cephalosporins occurs. Methods Isolates of Enterobacter spp. were sensitivity tested to a range of antibiotics, and selected isolates were DNA ¢ngerprinted by pulsed-¢eld gel electrophoresis.The medical records of all patients with positive cultures for Enterobacter spp. were reviewed to determine the e¡ect of previous antibiotic treatment on the susceptibility pro¢le of these organisms. Results The crude incidence of colonization/infection (n 315) was 0.51 per 100 patients and 0.73 per 1000 days of hospitalization.The 4-day and 7-day Kaplan^Meier rates of colonization/infection with Enterobacter were estimated to be 7.57% (standard deviation (SD 3.26%) and 4.16% (SD 2.88%)), respectively.The time lag to colonization/infection with isolates producing large amounts of Bush group 1 b-lactamase (HLBL) (27.35 þ 27.30 days) was signi¢cantly di¡erent from that to colonization/infection with wild-type isolates (13.59 þ 17.93 days) (P 0.036). Ninety-six isolates (30.5%) demonstrated acquired resistance to expanded-spectrum cephalosporins: 34 isolates (10.8%) produced extended-spectrum blactamase, and 62 isolates (19.7%) produced HLBL.The 89 Enterobacter isolates susceptible to thirdgeneration cephalosporins yielded 84 major DNA patterns, and the 45 HLBL isolates yielded 38 major DNA patterns.The risk of colonization/infection with HLBL-producing Enterobacter was higher in cases of antimicrobial treatment with third-generation cephalosporins or a £uoroquinolone, and in cases of urinary tract colonization/infection. Conclusions The judicious use in hospitals of both expanded-spectrum cephalosporins and other antibiotics such as £uoroquinolones is necessary to curtail the emergence of resistance in Enterobacter spp.

Research paper thumbnail of Wastewater treatment plants release large amounts of extended-spectrum β-lactamase-producing escherichia coli into the environment

See the Editorial Commentary by Griffiths and Barza on pages 1666-7.) Background. The determinant... more See the Editorial Commentary by Griffiths and Barza on pages 1666-7.) Background. The determinants of the spread of extended-spectrum β-lactamase-producing Escherichia coli (ESBLEC) in the community remain unclear. To evaluate its dissemination in the environment, we analyzed the ESBLEC population throughout an urban wastewater network. Methods. Samples were collected weekly, over a 10-week period, from 11 sites throughout the wastewater network of Besançon city (France). Total E. coli and ESBLEC loads were determined for each sample. As a control, we analyzed 51 clinical ESBLEC isolates collected at our hospital. We genotyped both environmental and clinical ESBLEC by pulsedfield gel electrophoresis and multilocus sequence typing and identified their bla ESBL genes by sequencing. Results. The E. coli load was higher in urban wastewater than in hospital wastewater (7.5 × 10 5 vs 3.5 × 10 5 CFU/mL, respectively). ESBLEC was recovered from almost all the environmental samples and accounted for 0.3% of total E. coli in the untreated water upstream from the wastewater treatment plant (WWTP). The ESBLEC load was higher in hospital wastewater than in community wastewater (27 × 10 3 vs 0.8 × 10 3 CFU/mL, respectively). Treatment by the WWTP eliminated 98% and 94% of total E. coli and ESBLEC, respectively. The genotyping revealed considerable diversity within both environmental and clinical ESBLEC and the overrepresentation of some clonal complexes. Most of the sequence types displayed by the clinical isolates were also found in the environment. CTX-M enzymes were the most common enzymes whatever the origin of the isolates. Conclusions. The treatment at the WWTP led to the relative enrichment of ESBLEC. We estimated that >600 billion of ESBLEC are released into the river Doubs daily and the sludge produced by the WWTP, used as fertilizer, contains 2.6 × 10 5 ESBLEC per gram.

Research paper thumbnail of Epidemiology and risk factors of Staphylococcus aureus CC398 bone and joint infections

BMC Infectious Diseases, May 29, 2020

Research paper thumbnail of Genome-based typing reveals rare events of patient contamination with Pseudomonas aeruginosa from other patients and sink traps in a medical intensive care unit

Background We used genome-based typing data with the aim of identifying the routes of acquisition... more Background We used genome-based typing data with the aim of identifying the routes of acquisition of Pseudomonas aeruginosa (PA) by patients hospitalized in a medical intensive care unit (MICU) over a long period in a non-epidemic context. Methods This monocentric prospective study took place over 10 months in 2019 in a 15-bed MICU that applies standard precautions of hygiene. Lockable sink traps installed at all water points of use were bleach disinfected twice a week. We sampled all sink traps weekly to collect 404 PA environmental isolates and collected all PA isolates (n = 115) colonizing or infecting patients (n = 65). All isolates had their phenotypic resistance profile determined and their genome sequenced, from which we identified resistance determinants and assessed the population structure of the collection at the nucleotide level to identify events of PA transmission. Results All sink traps were positive for PA, each sink trap being colonized for several months by one or ...

Research paper thumbnail of The rise and the fall of aPseudomonas aeruginosaepidemic lineage in a hospital

The biological features that allow a pathogen to survive in the hospital environment are mostly u... more The biological features that allow a pathogen to survive in the hospital environment are mostly unknown. The extinction of bacterial epidemics in hospitals is mostly attributed to changes in medical practice, including infection control, but the role of bacterial adaptation has never been documented. We analyzed a collection ofPseudomonas aeruginosaisolates belonging to the Besançon Epidemic Strain (BES), responsible for a 12-year nosocomial outbreak, using a genotype-to-phenotype approach. Bayesian analysis estimated the emergence of the clone in the hospital five years before its opening, during the creation of its water distribution network made of copper. BES survived better than the reference strains PAO1 and PA14 in a copper solution due to a genomic island containing 13 metal-resistance genes and was specifically able to proliferate in the ubiquitous amoebaVermamoeba vermiformis. Mutations affecting amino-acid metabolism, antibiotic resistance, lipopolysaccharide biosynthesis...

Research paper thumbnail of Occurrence and ecological determinants of the contamination of floodplain wetlands with Klebsiella pneumoniae and pathogenic or antibiotic-resistant Escherichia coli

FEMS Microbiology Ecology, 2019

The survival and multiplication of human pathogenic and antibiotic-resistant bacteria in ecosyste... more The survival and multiplication of human pathogenic and antibiotic-resistant bacteria in ecosystems is of increasing concern but has been little explored. Wetlands can be contaminated by water fluxes from rivers and may present environmental conditions leading to bacterial survival and multiplication. To test this hypothesis, we sampled 16 wetlands located along three rivers of the Jura Massif, France. The bacterial contamination of the wetland and river waters was measured monthly over a one-year cycle together with the water physico-chemical characteristics. We assessed the abundance of three pathogenic species: Escherichia coli,Klebsiella pneumoniaeand Pseudomonas aeruginosa. The concentrations of E. coli producing extended-spectrum β-lactamase (ESBL E. coli) or belonging to the phylogenetic group B2 (E. coli B2–more pathogenic) were also measured. We found that rivers carried total E. coli, ESBL E. coli, and K. pneumoniae to wetlands. ESBL E. coli poorly survived in wetlands, wh...

Research paper thumbnail of Contamination of a hospital plumbing system by persister cells of a copper-tolerant high-risk clone of Pseudomonas aeruginosa

Water Research, 2019

Background. Pseudomonas aeruginosa (PA) is an important opportunistic pathogen that thrives best ... more Background. Pseudomonas aeruginosa (PA) is an important opportunistic pathogen that thrives best in the distal elements of plumbing and waste-water systems. Although nosocomial outbreaks of PA have been associated with water sources, the role of the plumbing system of healthcare premises as a reservoir for this pathogen is still unclear. Materials and methods. We collected water samples from 12 technical areas, distant from any medical activity, in a teaching hospital in France once a week for 11 weeks. We used a method that resuscitates persister cells because of the nutrient-poor conditions and the presence of inhibitors (e.g. chlorine and copper ions). Briefly, water was sampled in sterile bottles containing 100 µM of the copper-ion chelating agent diethyldithiocarbamate (DDTC). A portion of the samples was immediately filtered through 0.45-µm membranes, deposited on R2A agar plates, and incubated seven days at 22°C (following European recommendations). The remaining water was incubated 14 days at 22°C and then filtered and cultured on R2A, blood-, or cetrimide-containing agar plates. PA isolates were identified by MS MALDI-TOF, genotyped by PFGE and WGS, and tested for survival in a 150 µg/L copper (II) sulphate solution. Results. Although the 12 water sampling points always tested negative with the recommended method, 67% were positive at least once for PA with the adapted method (i.e. with DDTC). The 14 PA persister isolates found throughout the plumbing system were clonal and belong to the high-risk clone ST308. Their genome harbours a 37-kb genomic island (GI-7) containing 13 genes linked to copper resistance. ST308 survived better in the copper solution than comparators that did not harbour GI-7 (P. aeruginosa strains PAO1, PA14, and ST235). The deletion of GI-7 in ST308 abrogated its tolerance to copper. The GI-7 nucleotide sequence shares 98% and 72% identity with sequences from the environmental 3 species Pseudomonas putida and the phytopathogenic species Pseudomonas syringae, respectively. Conclusion. We report the contamination of the plumbing system of a healthcare premises by persister cells of the high-risk clone P. aeruginosa ST308. New recommendations for the monitoring of water contamination should consider persister cells. The genomic island GI-7, which confers tolerance to copper, probably originates from Pseudomonas species found in copper-contaminated soils and plants. Agricultural practices may have an unexpected consequence, allowing copper-tolerant pathogens to survive in the hospital environment and contaminate fragile patients.

Research paper thumbnail of A nonlinear time-series analysis approach to identify thresholds in associations between population antibiotic use and rates of resistance

Nature Microbiology, 2019

Balancing access to antibiotics with control of antibiotic resistance is a global public health p... more Balancing access to antibiotics with control of antibiotic resistance is a global public health priority. Currently, antibiotic stewardship is informed by a 'use it and lose it' principle, in which population antibiotic use is linearly related to resistance rates. However, theoretical and mathematical models suggest use-resistance relationships are non-linear. One explanation is that resistance genes are commonly associated with 'fitness costs', impairing pathogen replication or transmissibility. Therefore, resistant genes and pathogens may only gain a survival advantage where antibiotic selection pressures exceed critical thresholds. These thresholds may provide quantitative targets for stewardship: optimising control of resistance while avoiding over-restriction of antibiotics. We evaluated the generalisability of a nonlinear time-series analysis approach for identifying thresholds using historical prescribing and microbiological data from five populations in Europe. We identified minimum thresholds in temporal relationships between use of selected antibiotics and rates of carbapenem-resistant Acinetobacter baumannii (in Hungary), extended spectrum β-lactamase producing Escherichia coli (Spain), cefepime-resistant Escherichia coli (Spain), gentamicin-resistant Pseudomonas aeruginosa (France), and methicillin-resistant Staphylococcus aureus (Northern Ireland) in different epidemiological phases. Using routinely generated data, our approach can identify context-specific quantitative targets for rationalising population antibiotic use and controlling resistance. Prospective intervention studies restricting antibiotic consumption are needed to validate thresholds.

Research paper thumbnail of Impact of a long-term antibiotic stewardship program targeting fluoroquinolones in a French local hospital

Médecine et Maladies Infectieuses, 2019

Introduction. Fluoroquinolones (FQs) are major antibiotics but their wide use in hospital and com... more Introduction. Fluoroquinolones (FQs) are major antibiotics but their wide use in hospital and community settings has led to an increased bacterial resistance against this antibiotic class. We aimed to assess the efficiency of an antibiotic stewardship program targeting FQs in a local hospital, and its impact on bacterial resistance. Methods. This observational study was conducted in the local hospital of Morteau (Franche-Comté region, East of France). The hospital has 166 beds with health and medico-social sectors and a medical home affiliated with the facility. Local guidelines on empirical treatment regimens was released in 2007 aiming to reduce the use of FQs, especially for urinary tract infections. The following monitoring indicators were assessed: total consumption of antibiotics and of FQs (DDD/1,000 hospital patient-days), and resistance to nalidixic acid among Escherichia coli strains. Changes in the number of FQ packs sold in a community pharmacy were also recorded. Results. The FQ consumption decreased by 85.6% between 2006 and 2015 (from 41.1 to 5.9 DDD/1,000 patient-days). The resistance to nalidixic acid among E. coli strains substantially decreased after remaining steady until 2011 (-57.2% between 2007 and 2015). The number of norfloxacin packs sold in the assessed community pharmacy decreased by 88%. Conclusion. Setting up an antibiotic stewardship program in a local hospital can lead to a substantial reduction in FQ use and in E. coli resistance to FQs. It may also have a positive impact on community prescriptions. RÉSUMÉ Introduction. Les fluoroquinolones (FQ) sont des antibiotiques majeurs dont la large utilisation, à l'hôpital comme en ville, a entraîné une augmentation de la résistance bactérienne contre cette classe. Notre objectif était d'évaluer l'efficacité d'une politique de bon usage des antibiotiques ciblant les FQ et d'évaluer son impact sur la résistance bactérienne. Méthodes. Étude observationnelle au centre hospitalier de Morteau (Franche-Comté), comportant des lits en secteurs sanitaire et médico-social (166 lits au total) et une maison médicale attachée à la structure. Un guide local de prescription probabiliste des antibiotiques, axé sur l'épargne des FQ (notamment dans le traitement des infections urinaires) a été diffusé en 2007. Le suivi des consommations et de la résistance était fondé sur des indicateurs (DDJ/1 000 journées d'hospitalisation et pourcentage de résistance à l'acide nalidixique chez Escherichia coli). L'évolution du nombre de boîtes de FQ vendues dans une pharmacie de la ville a été recueillie.

Research paper thumbnail of Higher third-generation cephalosporin prescription proportion is associated with lower probability of reducing carbapenem use: a nationwide retrospective study

Antimicrobial resistance and infection control, 2018

The ongoing extended spectrum β-lactamase-producing (ESBL-PE) pandemic has led to an increasing c... more The ongoing extended spectrum β-lactamase-producing (ESBL-PE) pandemic has led to an increasing carbapenem use, requiring release of guidelines for carbapenem usage in France in late 2010. We sought to determine factors associated with changes in carbapenem use in intensive care units (ICUs), medical and surgical wards between 2009 and 2013. This ward-level multicentre retrospective study was based on data from French antibiotic and multidrug-resistant bacteria surveillance networks in healthcare facilities. Antibiotic use was expressed in defined daily doses per 1000 patient-days. Factors associated with the reduction in carbapenem use (yes/no) over the study period were determined from random-effects logistic regression model (493 wards nested within 259 healthcare facilities): ward characteristics (type, size…), ward antibiotic use (initial antibiotic use [i.e., consumption of a given antibiotic in 2009], initial antibiotic prescribing profile [i.e., proportion of a given antibio...

Research paper thumbnail of The health and economic burden of bloodstream infections caused by antimicrobial-susceptible and non-susceptible Enterobacteriaceae and Staphylococcus aureus in European hospitals, 2010 and 2011: a multicentre retrospective cohort study

Euro surveillance : bulletin Européen sur les maladies transmissibles = European communicable disease bulletin, Jan 18, 2016

We performed a multicentre retrospective cohort study including 606,649 acute inpatient episodes ... more We performed a multicentre retrospective cohort study including 606,649 acute inpatient episodes at 10 European hospitals in 2010 and 2011 to estimate the impact of antimicrobial resistance on hospital mortality, excess length of stay (LOS) and cost. Bloodstream infections (BSI) caused by third-generation cephalosporin-resistant Enterobacteriaceae (3GCRE), meticillin-susceptible (MSSA) and -resistant Staphylococcus aureus (MRSA) increased the daily risk of hospital death (adjusted hazard ratio (HR) = 1.80; 95% confidence interval (CI): 1.34-2.42, HR = 1.81; 95% CI: 1.49-2.20 and HR = 2.42; 95% CI: 1.66-3.51, respectively) and prolonged LOS (9.3 days; 95% CI: 9.2-9.4, 11.5 days; 95% CI: 11.5-11.6 and 13.3 days; 95% CI: 13.2-13.4, respectively). BSI with third-generation cephalosporin-susceptible Enterobacteriaceae (3GCSE) significantly increased LOS (5.9 days; 95% CI: 5.8-5.9) but not hazard of death (1.16; 95% CI: 0.98-1.36). 3GCRE significantly increased the hazard of death (1.63; ...

Research paper thumbnail of Marked increase in incidence for bloodstream infections due to Escherichia coli, a side effect of previous antibiotic therapy in the elderly

Frontiers in Microbiology, 2015

We conducted a survey including 3334 bloodstream infections (BSIs) due to E.coli diagnosed in 200... more We conducted a survey including 3334 bloodstream infections (BSIs) due to E.coli diagnosed in 2005-2014 at a stable cohort of hospitals. Marked increases in incidence were observed for community-acquired (CA) BSIs in patients aged >75 years, CA-BSIs of digestive origin in patients aged 60-74 years, healthcare-associated BSIs, and BSIs associated with ESBL (extended-spectrum B-lactamase)-producing E. coli (ESBLEc). Using MLST, we studied the genetic diversity of 412 BSI isolates recovered during the 2014 survey: 7 major sequence type complexes (STCs) were revealed in phylogenetic group B2, 3 in group A/B1 and 2 in group D. Among the 31 ESBLEc isolates, 1/3 belonged to STC 131. We searched for possible associations between clonal groups, clinical determinants and characteristics of BSIs: isolates from groups B2 (except STC 131) and D were susceptible to antibiotics and associated with BSIs of urinary origin in patients <60 years. STC 131 and group A/B1 isolates were multi-drug resistant and associated with CA-BSIs of digestive origin in patients aged 60-74 with a recent history of antibiotic treatment. STC 131 isolates were associated with HCA-BSIs in patients with recent/present hospitalization in a long-stay unit. We provide a unique population-based picture of the epidemiology of E. coli BSI. The aging nature of the population led to an increase in the number of cases caused by the B2 and D isolates generally implicated in BSIs. In addition, the association of a trend toward increasing rates of gut colonization with multi drug-resistant isolates revealed by the rise in the incidence of BSIs of digestive origin caused by STC 131 and A/B1 (STCs 10, 23, and 155) isolates, and a significant increase in the frequency of BSIs in elderly patients with recent antibiotic treatment suggested that antibiotic use may have contributed to the growing incidence of BSI.

Research paper thumbnail of Bacterial contamination of the hospital environment during wound dressing change | Contamination bactérienne de l'environnement hospitalier lors du changement de pansements des plaies chroniques

ABSTRACT Introduction L’environnement inerte hospitalier joue un rôle dans la transmission croisé... more ABSTRACT Introduction L’environnement inerte hospitalier joue un rôle dans la transmission croisée des bactéries multirésistantes. L’objectif de l’étude était de déterminer le taux de contamination bactérienne de l’environnement lors de la réfection des pansements de plaies chroniques en fonction de la nature des espèces colonisant la plaie. L’hypothèse était que les plaies colonisées avec perte de substance entraînaient une contamination de l’environnement plus importante que les plaies non colonisées. Patients et méthodes De juillet 2010 à mai 2011, des prélèvements d’environnement (air et surfaces) ont été réalisés dans les chambres des patients porteurs de plaies colonisées (cas, n = 9) lors et hors réfection de pansements. Ont été dénombrés : Staphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter baumannii et entérobactéries. La contamination bactérienne observée a été comparée à celle correspondant à des patients porteurs de plaies non colonisées (témoins, n = 15). Résultats L’environnement était fréquemment contaminé lors de la réfection de pansements : 38 % des séries de prélèvements étaient positives. La fréquence de contamination était moins élevée pour les cas hors réfection de pansement (14,3 %) et pour les témoins (3,8 %). L’espèce S. aureus était la plus fréquemment isolée. Discussion Les résultats observés plaident en faveur de mesures déjà largement recommandées : port de masques par les soignants pour la réalisation des soins de plaies et désinfection des mains après contact avec l’environnement du patient. Mais, d’autres mesures méritent d’être proposées, notamment la réalisation du bionettoyage de la chambre avant et après la réfection de pansement sur plaies colonisées. Niveau de preuve Niveau III. Étude prospective cas-témoin.

Research paper thumbnail of Clonal Complex 398 Methicillin Susceptible Staphylococcus aureus: A Frequent Unspecialized Human Pathogen with Specific Phenotypic and Genotypic Characteristics

PLoS ONE, 2013

Clonal complex 398 livestok-associated-MRSA (CC398 LA-MRSA) clone is described as a major animal ... more Clonal complex 398 livestok-associated-MRSA (CC398 LA-MRSA) clone is described as a major animal pathogen that can also colonize and infect humans. CC398 methicillin susceptible Staphylococcus aureus (CC398 MSSA) is less described. We identified 126 CC398 MSSA strains of human origin within 6380 S. aureus isolates gathered between 2009 and 2011, from the French National Reference Centre for Staphylococci. They were characterized using antimicrobial susceptibility testing, spa typing, DNA microarrays (Identibac S. aureus Genotyping H, Alere), CC398-specific sequence PCR, ermT (encoding macrolides résistance) PCR. Fifty-three CC398 LA-MRSA collected from French pigs and veal were used as comparators, and phylogenetic relations between human CC398 MSSA and animal CC398 MRSA populations were explored on the basis of spa-typing and DNA microarrays. CC398 MSSA were able to induce a large spectrum of infections (especially skin, bloodstream, and pneumonias). The prevalence rate of this clone was high in MSSA population, i.e., 24.7% in a local prospective study on nasal colonization, and 7.5% in a national prospective study on infective endocarditis. CC398 MSSA isolates were frequently (89%) erythromycin resistant, due to the presence of the ermT gene, a gene not detected in erythromycin resistant CC398 LA-MRSA strains. Expression of staphylococcal complement inhibitor (scn) and the chemotaxis inhibitory protein (chp), was also specific to this population. The CC398 MRSA signature included also a panel of antibiotic resistance genes, especially a type IV or V cassette mec and tetM. CC398 MSSA and CC398 LA-MRSA populations were closely related based on spa-typing and DNA microarrays, with the MRSA strains forming the most derived lineage in phylogenic trees. Both MSSA and MRSA populations may come from common ancestors, which would have evolved in the settings of different selective pressures, explaining the acquisition of ermT, chp and scn for MSSA, and antibiotic resistance genes for MRSA.

Research paper thumbnail of Methicillin-Susceptible ST398 Staphylococcus aureus Responsible for Bloodstream Infections: An Emerging Human-Adapted Subclone?

PLoS ONE, 2011

for the Bloodstream Infection Study Group of the Ré seau des Hygié nistes du Centre (RHC)

Research paper thumbnail of Tracking Down Antibiotic-Resistant Pseudomonas aeruginosa Isolates in a Wastewater Network

PLoS ONE, 2012

The Pseudomonas aeruginosa-containing wastewater released by hospitals is treated by wastewater t... more The Pseudomonas aeruginosa-containing wastewater released by hospitals is treated by wastewater treatment plants (WWTPs), generating sludge, which is used as a fertilizer, and effluent, which is discharged into rivers. We evaluated the risk of dissemination of antibiotic-resistant P. aeruginosa (AR-PA) from the hospital to the environment via the wastewater network. Over a 10-week period, we sampled weekly 11 points (hospital and urban wastewater, untreated and treated water, sludge) of the wastewater network and the river upstream and downstream of the WWTP of a city in eastern France. We quantified the P. aeruginosa load by colony counting. We determined the susceptibility to 16 antibiotics of 225 isolates, which we sorted into three categories (wild-type, antibiotic-resistant and multidrug-resistant). Extended-spectrum blactamases (ESBLs) and metallo-b-lactamases (MBLs) were identified by gene sequencing. All non-wild-type isolates (n = 56) and a similar number of wild-type isolates (n = 54) were genotyped by pulsed-field gel electrophoresis and multilocus sequence typing. Almost all the samples (105/110, 95.5%) contained P. aeruginosa, with high loads in hospital wastewater and sludge ($3610 6 CFU/l or/kg). Most of the multidrug-resistant isolates belonged to ST235, CC111 and ST395. They were found in hospital wastewater and some produced ESBLs such as PER-1 and MBLs such as IMP-29. The WWTP greatly reduced P. aeruginosa counts in effluent, but the P. aeruginosa load in the river was nonetheless higher downstream than upstream from the WWTP. We conclude that the antibiotic-resistant P. aeruginosa released by hospitals is found in the water downstream from the WWTP and in sludge, constituting a potential risk of environmental contamination.

Research paper thumbnail of Usefulness of antimicrobial resistance pattern for detecting PVL- or TSST-1-producing meticillin-resistant Staphylococcus aureus in a French university hospital

Journal of Medical Microbiology, 2009

Several recent reports have suggested that community-associated meticillin-resistant Staphylococc... more Several recent reports have suggested that community-associated meticillin-resistant Staphylococcus aureus (MRSA) clones, particularly those harbouring genes for Panton–Valentine leukocidin (PVL) or toxic shock syndrome toxin 1 (TSST-1), are increasingly responsible for infections in hospitals. Here, a retrospective study was carried out to investigate whether antimicrobial resistance patterns could be used to detect these pathogens in a French university hospital. Isolates were characterized by antimicrobial susceptibility testing, PCR profiling (PVL genes and tst), PFGE typing and multilocus sequence typing. Demographic and clinical data were collected from all patients. For PVL-positive MRSA, the typical antimicrobial resistance pattern (susceptible to fluoroquinolones, non-susceptible to fusidic acid, kanamycin resistant and susceptible to gentamicin and tobramycin) had a sensitivity of 77.8 % and a positive predictive value (PPV) of 100 %. For tst-positive MRSA, the antimicrobi...

Research paper thumbnail of Antibiotics involved in the occurrence of antibiotic-resistant bacteria: a nationwide multilevel study suggests differences within antibiotic classes

Journal of Antimicrobial Chemotherapy, 2012

To identify the antibiotics potentially the most involved in the occurrence of antibiotic-resista... more To identify the antibiotics potentially the most involved in the occurrence of antibiotic-resistant bacteria from an ecological perspective in French healthcare facilities (HCFs). Methods: This study was based on data from the French antimicrobial surveillance network (ATB-RAISIN, 2007-09). Antibiotics were expressed in defined daily doses per 1000 patient-days. Antibiotic-resistant bacteria were considered as count data adjusted for patient-days. These were third-generation cephalosporin (3GC)and ciprofloxacin-resistant Escherichia coli, cefotaxime-resistant Enterobacter cloacae, methicillin-resistant Staphylococcus aureus and ceftazidime-, imipenem-and ciprofloxacin-resistant Pseudomonas aeruginosa. Three-level negative binomial regression models were built to take into account the hierarchical structure of data: level 1, repeated measures each year (count outcome, time, antibiotics); level 2, HCFs (type and size); and level 3, regions (geographical area). Results: A total of 701 HCFs from 20 French regions and up to 1339 HCF-years were analysed. The use of ceftriaxone, but not of cefotaxime, was positively correlated with incidence rates of 3GC-and ciprofloxacin-resistant E. coli. In contrast, both 3GCs were positively correlated with the incidence rate of cefotaxime-resistant E. cloacae. Higher levels of use of ciprofloxacin and/or ofloxacin, but not of levofloxacin, were associated with higher incidence rates of 3GC-and ciprofloxacin-resistant E. coli, cefotaxime-resistant E. cloacae, methicillin-resistant S. aureus and ceftazidime-and ciprofloxacin-resistant P. aeruginosa. Conclusions: Our study suggests differences within antibiotic classes in promoting antibiotic resistance. We identified ceftriaxone, ciprofloxacin and ofloxacin as priority targets in public health strategies designed to reduce antibiotic use and antibiotic-resistant bacteria in French HCFs.

Research paper thumbnail of Antibiotic susceptibility and genotypic characterization of Haemophilus influenzae strains isolated from nasopharyngeal specimens from children in day-care centers in eastern France

Clinical Microbiology and Infection, 2000

Objective To determine the overall carriage rate for Haemophilus in£uenzae in young children in d... more Objective To determine the overall carriage rate for Haemophilus in£uenzae in young children in day-care centers, the frequency of resistance to various classes of antibiotic, and the clonal relationship between isolates of the various resistant phenotypes. Methods Nasopharyngeal (NP) specimens were obtained and cultured on chocolate agar with bacitracin. Antibiotic susceptibility testing and serotyping were performed for all isolates.The genetic polymorphism of ampicillin-susceptible and b-lactamase-producing isolates was studied by pulsed-¢eld gel electrophoresis using SmaI. Results Of the 596 NP secretion cultures, 152 (25.5%) were positive for H. in£uenzae. Sixty-four (42.1%) isolates produced b-lactamase and two (1.3%) were ampicillin resistant but did not produce b-lactamase. We were unable to serotype 150 isolates; one isolate belonged to capsular serotype e and one to serotype f. Forty-six major DNA patterns were identi¢ed among 76 randomized isolates. b-lactamase producing isolates more frequently showed EP than ampicillin-susceptible isolates P < 10 À4 .The frequency of isolates with EP was signi¢cantly lower in day-care centers attended by less than 20 children than in those attended by more than 20 children (P 0.020). Conclusions Resistance due to b-lactamase production has disseminated in some day-care centers, mostly by person-to-person spread but also via the possible conjugal transfer of large plasmids between strains.The size of day-care centers may a¡ect the risk of transmission.

Research paper thumbnail of Susceptibility of Escherichia coli to the amoxycillin-clavulanate combination: which recommendations should be used to provide relevant information to clinicians?

Clinical Microbiology and Infection, 2005

Chlamydia trachomatis has been recognised as a major bacterial sexually transmitted disease (STD)... more Chlamydia trachomatis has been recognised as a major bacterial sexually transmitted disease (STD) in north America and western Europe [1]. The prevalence of infection for men in STD settings is 15-20%, with a corresponding figure for women

Research paper thumbnail of Clinical and molecular epidemiology of chromosome-mediated resistance to third-generation cephalosporins in Enterobacter isolates in eastern France

Clinical Microbiology and Infection, 2000

Objective To determine both the prevalence of group I b-lactamase-related resistance and the clin... more Objective To determine both the prevalence of group I b-lactamase-related resistance and the clinical setting in which resistance to expanded-spectrum cephalosporins occurs. Methods Isolates of Enterobacter spp. were sensitivity tested to a range of antibiotics, and selected isolates were DNA ¢ngerprinted by pulsed-¢eld gel electrophoresis.The medical records of all patients with positive cultures for Enterobacter spp. were reviewed to determine the e¡ect of previous antibiotic treatment on the susceptibility pro¢le of these organisms. Results The crude incidence of colonization/infection (n 315) was 0.51 per 100 patients and 0.73 per 1000 days of hospitalization.The 4-day and 7-day Kaplan^Meier rates of colonization/infection with Enterobacter were estimated to be 7.57% (standard deviation (SD 3.26%) and 4.16% (SD 2.88%)), respectively.The time lag to colonization/infection with isolates producing large amounts of Bush group 1 b-lactamase (HLBL) (27.35 þ 27.30 days) was signi¢cantly di¡erent from that to colonization/infection with wild-type isolates (13.59 þ 17.93 days) (P 0.036). Ninety-six isolates (30.5%) demonstrated acquired resistance to expanded-spectrum cephalosporins: 34 isolates (10.8%) produced extended-spectrum blactamase, and 62 isolates (19.7%) produced HLBL.The 89 Enterobacter isolates susceptible to thirdgeneration cephalosporins yielded 84 major DNA patterns, and the 45 HLBL isolates yielded 38 major DNA patterns.The risk of colonization/infection with HLBL-producing Enterobacter was higher in cases of antimicrobial treatment with third-generation cephalosporins or a £uoroquinolone, and in cases of urinary tract colonization/infection. Conclusions The judicious use in hospitals of both expanded-spectrum cephalosporins and other antibiotics such as £uoroquinolones is necessary to curtail the emergence of resistance in Enterobacter spp.

Research paper thumbnail of Wastewater treatment plants release large amounts of extended-spectrum β-lactamase-producing escherichia coli into the environment

See the Editorial Commentary by Griffiths and Barza on pages 1666-7.) Background. The determinant... more See the Editorial Commentary by Griffiths and Barza on pages 1666-7.) Background. The determinants of the spread of extended-spectrum β-lactamase-producing Escherichia coli (ESBLEC) in the community remain unclear. To evaluate its dissemination in the environment, we analyzed the ESBLEC population throughout an urban wastewater network. Methods. Samples were collected weekly, over a 10-week period, from 11 sites throughout the wastewater network of Besançon city (France). Total E. coli and ESBLEC loads were determined for each sample. As a control, we analyzed 51 clinical ESBLEC isolates collected at our hospital. We genotyped both environmental and clinical ESBLEC by pulsedfield gel electrophoresis and multilocus sequence typing and identified their bla ESBL genes by sequencing. Results. The E. coli load was higher in urban wastewater than in hospital wastewater (7.5 × 10 5 vs 3.5 × 10 5 CFU/mL, respectively). ESBLEC was recovered from almost all the environmental samples and accounted for 0.3% of total E. coli in the untreated water upstream from the wastewater treatment plant (WWTP). The ESBLEC load was higher in hospital wastewater than in community wastewater (27 × 10 3 vs 0.8 × 10 3 CFU/mL, respectively). Treatment by the WWTP eliminated 98% and 94% of total E. coli and ESBLEC, respectively. The genotyping revealed considerable diversity within both environmental and clinical ESBLEC and the overrepresentation of some clonal complexes. Most of the sequence types displayed by the clinical isolates were also found in the environment. CTX-M enzymes were the most common enzymes whatever the origin of the isolates. Conclusions. The treatment at the WWTP led to the relative enrichment of ESBLEC. We estimated that >600 billion of ESBLEC are released into the river Doubs daily and the sludge produced by the WWTP, used as fertilizer, contains 2.6 × 10 5 ESBLEC per gram.