[Methicillin-sensitive Staphylococcus aureus isolates related to USA300 clone: Origin of community-genotype MRSA in Colombia?] (original) (raw)
Characterisation of Staphylococcus aureus bacteraemia at Tygerberg hospital
The Southern African journal of epidemiology & infection: official journal of the Sexually Transmitted Diseases, Infectious Diseases and Epidemiological Societies of Southern Africa
To elucidate the local epidemiology of Staphylococcus aureus bacteraemia, we characterised blood culture isolates using molecular methods and prospectively collected clinical data to determine the occurrence of community-acquired, methicillin resistant S. aureus (MRSA). Consecutive S. aureus blood culture isolates were collected over a one-year period from patients who were admitted to Tygerberg Academic Hospital in the Western Cape. A multiplex polymerase chain reaction (PCR) was used for the detection of spa, mecA and lukS/F-PV genes. Strain typing was performed using spa typing. Multiplex PCR for staphylococcal cassette chromosome mec (SCCmec) typing was also performed, as well as multilocus sequence typing (MLST) on selected isolates. Cases were categorised by clinical data as either hospital-acquired, healthcare-associated or community-acquired. One hundred and thirteen S. aureus isolates (30% MRSA) were collected from 104 cases of bacteraemia. According to clinical data, all c...
European Journal of Clinical Microbiology & Infectious Diseases, 2005
Heterogeneous methicillin-resistant Staphylococcus aureus (MRSA) strains, including community-acquired MRSA strains, have been observed in Central Europe. The purpose of this study was to characterize by molecular methods MRSA isolated during the period 2002–2003 at the Otto-von-Guericke University Hospital in Magdeburg, Germany, and at a nearby chronic care facility. Strains were analyzed for their resistance phenotype. Selected isolates were typed by multilocus sequence typing (MLST), by a multiplex polymerase chain reaction (PCR) for the staphylococcal cassette chromosome mec (SCCmec), by an allele-specific PCR for the staphylococcal accessory gene regulator (agr), and by PCR for the presence of toxin genes (sea–sej, tsst-1, hlgA, C, and B, lukE/D, and luk-pvl). Of the 2,731 S. aureus isolates studied, 199 (7.3%) were MRSA, with a prevalence of 21.6%, 19.6%, and 12% in the department of dermatology, the chronic care facility, and the intensive care units. Six different sequence types (ST247, ST228, ST22, ST22a, ST225, and ST45) were observed. Of these, ST22, ST22a, and ST45 dominated (>50%) in the department of dermatology and the chronic care facility. Strains with these sequence types were usually not resistant to gentamicin and were associated with agr group I, the SCCmec type IV element, and the presence of the sec and sed toxin genes. ST228 strains were found mainly in the intensive care units and had a broader resistance phenotype and were associated with agr group II and the SCCmec type I element. All luk-pvl-positive MRSA isolates (n=8) belonged to agr group I and were typed as ST22 or ST45 and contained the SCCmec type I (n=1), type III (n=1), or type IV (n=6) element. The main observations of this study are in concordance with previously reported findings showing dissemination of MRSA in Central Europe. Through the multitude of applied methods, the data from this study contribute to a more precise knowledge about the heterogeneity of MRSA in a clinical setting. Rapid dissemination of MRSA clones at a university hospital was demonstrated, indicating that dissemination may depend on the environmental conditions within the individual departments.
Periodic monitoring of Staphylococcus aureus characteristics in a locality is imperative as their drug-resistant variants cause treatment problem. In this study, antibiograms, prevalence of toxin genes (sea-see, seg-ser, seu, tsst-1, eta, etb, and etd), PFGE types, accessory gene regulator (agr) groups, and ability to form biofilm of 92 S. aureus Thailand clinical isolates were investigated. They were classified into 10 drug groups: groups 1-7 (56 isolates) were methicillin resistant (MRSA) and 8-10 (36 isolates) were methicillin sensitive (MSSA). One isolate did not have any toxin gene, 4 isolates carried one toxin gene (seq), and 87 isolates had two or more toxin genes. No isolate had see, etb, or tsst-1; six isolates had eta or etd. Combined seg-sei-sem-sen-seo of the highly prevalent egc locus was 26.1%. The seb, sec, sel, seu, and eta associated significantly with MSSA; sek was more in MRSA. The sek-seq association was 52.17% while combined sed-sej was not found. Twenty-three PFGE types were revealed, no association of toxin genes with PFGE types. All four agr groups were present; agr group 1 was predominant (58.70%) but agr group 2 strains carried more toxin genes and were more frequent toxin producers. Biofilm formation was found in 72.83% of the isolates but there was no association with antibiograms. This study provides insight information on molecular and phenotypic markers of Thailand S. aureus clinical isolates which should be useful for future active surveillance that aimed to control a spread of existing antimicrobial resistant bacteria and early recognition of a newly emerged variant. BioMed Research International cytokines and T-cell stimulating factors leading to toxic shock syndrome which may be fatal [8, 9]. The enterotoxicity and superantigenicity are distinct properties of the toxin molecule [6]. SEs are classified into two types based on their emetic activity in the toxin fed modeled primate. Toxins that induce vomiting in the primate are placed in the classical SE type while those that lack the emetic activity or have not been tested are allocated in the SE-like (SEls) type [10, 11]. Members of the classical SEs are SEA-SEE and the more recently recognized SEG, SEH, SEI, SER, SES, and SET. The SEls members include SElJ, SElK, SElL, SElM, SElN, SElO, SElP, SElQ, SElU, SElU2 or SEW, and SElV [11]. The staphylococcal enterotoxin F (SEF) which lacks emetic activity but is associated with toxic shock syndrome is presently called toxic shock syndrome toxin-1 (TSST-1) [12]. The SEs and the TSST-1 as well as the bacterial resistance to drugs are encoded by genes on the mobile genetic elements including prophages, plasmids, pathogenicity islands, genomic islands, and antibiotic resistance cassette [13]; thus they are transmitted horizontally rather easily. Expression of S. aureus virulence factors and metabolism of metabolic pathways during growth are coordinated/regulated by a quorumsensing operon named accessory gene regulator (agr) [14, 15]. Based on the amino acid sequence polymorphisms of the agr-encoding autoinducing peptides and their responding receptors, S. aureus strains can be divided into four major agr groups (groups 1-4) [16]. During the last five decades, S. aureus clones that resist methicillin (methicillin-resistant S. aureus, MRSA) disseminated and caused medical and public health problem worldwide [17, 18]. These strains are not only resistant to methicillin, but also resistant to all other-lactams, such as cephalosporin [18, 19]. In Thailand, MRSA infections were reported from 23 hospitals from 1988 to 1998 [20, 21]. The proportions of MRSA to MSSA in the northeast, central, and southern regions of the country during the studied period increased from 11 to 23.4%, 16 to 30.5%, and 21 to 30.3%, respectively [22]. Moreover, methicillin-resistant S. aureus with reduced susceptibility to vancomycin was recognized [23]. However, data on genotypic characteristics and other attributes of the S. aureus isolates in Thailand are relatively rare. Therefore, this study investigated the prevalence of virulence toxin genes coding for enterotoxins (sea-see, seg-ser, and seu), toxic shock syndrome toxin-1 (tsst-1), and exfoliative toxins (eta, etb, and etd) among S. aureus Thailand clinical isolates. Molecular diversity of the isolates regarding their endonuclease-restricted patterns of genomic DNA (PFGE), agr types, and antimicrobial susceptibility as well as their ability to produce biofilm were also investigated.
Tropical Medicine and International Health, 1998
Staphylococcus aureus is a major cause of nosocomial infections and a risk in patients who have either undergone surgery or are on haemodialysis. The S. aureus infections in patients admitted to the clinical departments of Al-Makased Charitable Hospital in Jerusalem during a period of one year were investigated. Isolates included were from blood, surgical wounds, or other nonsuperficial sites. Of 63 isolates available for analysis, 46 (73.0%) expressed type 8 capsular polysaccharide; 13 (20.7%), type 5 capsular polysaccharide; only 4 isolates (6.3%) did not express type 5 or type 8 antibodies. The strains fitted in 7 different antibiogram types, with the type showing resistance only to penicillin and ampicillin prevalent in 34 out of 63 isolates (54.0%). Of the 12 methicillin-resistant S. aureus (MRSA) isolates (19.1%), 8(66.7%) possessed the type 8 capsule and 4(33.7%) the type 5 capsule. Pulsed-field gel electrophoresis of all isolates with the restrictionendonuclease enzymes Sma I revealed 34 patterns demonstrating that no single methicillin-sensitive S. aureus strain was endemic in the hospital. However, all MRSA isolates with a type 8 capsule showed identical PFGE patterns using the 2 restriction-endonuclease enzymes Sma I and SST II. Moreover, type 5 isolates showed identical patterns (one isolate differed from the rest with one band only). These data suggest and confirm the clonality of type 5 and type 8 MRSA isolates. Analysing the results of the capsular and antibiogram typing schemes in conjunction proved useful and suggested that such an analysis can be employed as a helpful epidemiological tool in hospitals with limited resources.
Staphylococcus aureusNasal Carriage Among Patients and Health Care Workers in São Tomé and Príncipe
Microbial Drug Resistance, 2014
Methicillin-resistant Staphylococcus aureus (MRSA) is a major human pathogen worldwide. However, data on MRSA prevalence in the African continent are scarce and nonexistent for Sã o Tomé and Príncipe. In November 2010 and April 2012, a total of 332 individuals (258 patients and 74 health care workers [HCW]) from Hospital Dr. Ayres Menezes in Sã o Tomé and Príncipe, were screened for S. aureus and MRSA carriage. Fifty-two persons (15.7%) were S. aureus nasal carriers out of which 14 (26.9%) were colonized with MRSA. MRSA isolates belonged to three clonal complexes: CC8 (PFGE type B-ST8-t064/t451-IVg/V), CC88 (PFGE E-ST88-t186/t786-IVa), and CC5 (PFGE K-ST5-t105-IVa/PFGE K-ST105-t002-II). A higher genetic diversity was found among methicillin-susceptible S. aureus (MSSA) isolates where 58.5% (n = 24) belonged to four major lineages: PFGE type A-ST15-t084; PFGE C-ST508-t861 or related; PFGE D-ST152-t355 or related; and PFGE G-ST121-t159/t2304. Despite the common nonmultiresistant profile, 98% of the isolates harbored two or more virulence factors. Panton-Valentine leukocidine was detected in 36% of the isolates, all MSSA. S. aureus cross-transmission between HCW and patients in the pediatric and medicine wards and the detection of identical MRSA strains among patients in two different wards evidenced the need of implementation of additional infection control measures in this hospital.
Scientific Reports, 2022
Methicillin-resistant Staphylococcus aureus (MRSA) is responsible for hard-to-treat infections. The presence of 19 virulence genes in 120 MRSA isolates obtained from hospitalized patients and genetic relationships of these isolates were investigated. The eno (100%) and ebps (93.3%) genes encoding laminin-and elastin binding proteins, respectively, were ubiquitous. Other adhesion genes: fib (77.5%), fnbB (41.6%), bbp (40.8%), cna (30.8%) encoding proteins binding fibrinogen, fibronectin, bone sialoprotein and collagen, respectively, and map/eap (62.5%), encoding Eap, were also frequent. The etB and etD genes, encoding exfoliative toxins, were present in 15.6% and 12.5% isolates, respectively. The splA, splE and sspA, encoding serine protease were detected in 100%, 70.8% and 94.2% isolates, respectively. The tst gene, encoding toxic shock syndrome toxin-1 was found in 75% isolates. The cna, map/eap and tst genes were the most common in wound isolates and much less common in blood isolates. We identified 45 different spa types, t003 (21.7%) and t008 (18.8%) being the most common. The t003 was the most frequent among isolates from the respiratory tract (35.5%), while t008 in blood isolates (40%). Identification of virulence factors of MRSA is important for evaluation of pathogen transmission rate and disease development. Methicillin-resistant Staphylococcus aureus (MRSA) cause hard-to-treat infections in various patient populations, and thus is a serious health problem. Treatment of MRSA infections is a significant financial burden for medical institutions 1 . The gene mecA in MRSA genome, encodes an enzyme responsible for crosslinking the peptidoglycans in the bacterial cell wall called penicillin-binding protein 2a (PBP2a). Low affinity PBP2a to β-lactams results in resistance to β-lactam antibiotics including penicillins, cephalosporins (except for ceftaroline and ceftobiprole), and carbapenems 2 . Multidrug-resistant (MDR) MRSA isolates are often resistant to commonly used antibiotic groups, such as aminoglycosides, fluoroquinolones, macrolides, tetracycline and chloramphenicol . MRSA is responsible for skin and surgical wound infections but also may infect different parts of the body including lower respiratory tract, cause bloodstream infection (BSI) and toxin-mediated syndromes as well as life-threatening diseases . The studies show that the proportion of MRSA among all S. aureus isolates is between 13 and 89% 8,9 . MRSA remains a prominent pathogen with persistently high mortality 10 . The mortality rate of S. aureus bacteremia is around 20-30% 11 . A European report from a Finnish Hospital Infection Program showed that S. aureus ranked among the top three organisms causing bloodstream infections 12 . MRSA are widely spread in various countries, in hospital environments, in community and livestock . MRSA infections are routinely
Clinical Microbiology and Infection, 2013
Studies reporting on the population structure of Staphylococcus aureus in South Africa have focused only on methicillin-resistant S. aureus (MRSA). This study describes the population structure of S. aureus, including methicillin-susceptible S. aureus (MSSA) isolated from patients at Tygerberg Academic Hospital, Western Cape province. Pulsed-field gel electrophoresis (PFGE), detection of Panton-Valentine leukocidin (PVL), spa typing, multilocus sequence typing (MLST), agr typing and SCCmec typing were used to characterize strains. Of 367 non-repetitive S. aureus isolates collected over a period of 1 year, 56 (15.3%) were MRSA. Skin and soft tissue infections were the most frequent source (54.8%), followed by bone and joint (15.3%) and respiratory tract infections (7.7%). For strain typing, PFGE was the most discriminative method, and resulted in 31 pulsotypes (n = 345, 94.0%), as compared with 16 spa clonal complexes (CCs) (n = 344, 93.4%).
International Journal of Infectious Diseases, 2010
Adult community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) and methicillin-susceptible S aureus (CA-MSSA) skin and soft tissue infection (SSTI) in China is not well described. A prospective cohort of adults with SSTI was established between January 2009 and August 2010 at 4 hospitals in Beijing. Susceptibility testing and molecular typing, including multilocus sequence typing, spa, agr typing, and toxin detection were assessed for all S. aureus isolates. Overall, 501 SSTI patients were enrolled. Cutaneous abscess (40.7%) was the most common infection, followed by impetigo (6.8%) and cellulitis (4.8%). S. aureus accounted for 32.7% (164/501) of SSTIs. Five isolates (5/164, 3.0%) were CA-MRSA. The most dominant ST in CA-MSSA was ST398 (17.6%). The prevalence of Panton-Valentine Leukocidin (pvl) gene was 41.5% (66/159) in MSSA. Female, younger patients and infections requiring incision or drainage were more commonly associated with pvlpositive S. aureus (P,0.03); sec gene was more often identified in CC5 (P,0.03); seh gene was more prevalent in CC1 (P = 0.001). Importantly, ST59 isolates showed more resistance to erythromycin, clindamycin and tetracycline, and needed more surgical intervention. In conclusion, CA-MRSA infections were rare among adult SSTI patients in Beijing. Six major MSSA clones were identified and associated with unique antimicrobial susceptibility, toxin profiles, and agr types. A high prevalence of livestock ST398 clone (17.1% of all S. aureus infections) was found with no apparent association to animal contact.
Journal of Clinical Microbiology, 2008
The impact of bacterial genetic characteristics on the outcome of patients with Staphylococcus aureus infections is uncertain. This investigation evaluated potential associations between bacterial genotype and clinical outcome using isolates collected as part of an international phase 2 clinical trial (FAST II) evaluating telavancin for the treatment of complicated skin and skin structure infections (cSSSI). Ninety S. aureus isolates from microbiologically evaluable patients with cSSSI enrolled in the FAST II trial from 11 sites in the United States (56 isolates, or 62%) and 7 sites in South Africa (34 isolates, or 38%) were examined for staphylococcal cassette chromosome mec, agr, and the presence of 31 virulence genes and subjected to pulsed-field gel electrophoresis (PFGE). South African methicillin-susceptible S. aureus (MSSA) isolates were more likely to carry certain virulence genes, including sdrD (P ؍ 0.01), sea (P < 0.01), and pvl (P ؍ 0.01). All 44 (49%) methicillin-resistant S. aureus (MRSA) isolates were from the United States; 37 (84%) were strain USA 300 by PFGE. In the United States, MRSA isolates were more likely than MSSA isolates to carry genes for sdrC (P ؍ 0.03), map/eap (P ؍ 0.05), fnbB (P ؍ 0.11), tst (P ؍ 0.02), sea (P ؍ 0.04), sed (P ؍ 0.04), seg (P ؍ 0.11), sej (P ؍ 0.11), agr (P ؍ 0.09), V8 (P ؍ 0.06), sdrD, sdrE, eta, etb, and see (P < 0.01 for all). MRSA isolates were more often clonal than MSSA isolates by PFGE. Isolates from patients who were cured were significantly more likely to contain the pvl gene than isolates from patients that failed or had indeterminate outcomes (79/84 [94%] versus 3/6 [50%]; P ؍ 0.01). S. aureus strains from different geographic regions have different distributions of virulence genes.
Journal of Clinical Microbiology, 2006
Staphylococcus aureus (MRSA) clones at the Institute for Microbiology at the University of Magdeburg (B. Ghebremedhin, W. König, and B. König, Eur. J. Clin. Microbiol. Infect. Dis. 24:388-398, 2005). The majority of them harbored the readily transmissible mec cassette type IV. Thus, theoretically, methicillin-susceptible Staphylococcus aureus (MSSA) might capture the mecA gene from circulating MRSA, or MRSA strains might catch mobile toxin genes from MSSA. Therefore, we characterized MSSA strains circulating at the University Hospital in Magdeburg. Among a total of 84 MSSA strains under study, about 40% possessed the tst (toxic shock syndrome toxin) gene and up to four additional enterotoxin genes. tst-positive MSSA strains belonged to all known agr groups (I to IV) and
Molecular typing of Staphylococcus aureus collected from a Major Hospital in Amman, Jordan
The Journal of Infection in Developing Countries, 2014
Introduction: Over the past decade methicillin-resistant Staphylococcus aureus (MRSA) has been recognized as a major cause of healthcare associated infections. Recently, however, epidemiology of this pathogen has changed drastically with the emergence of new clones in the community. Efficient epidemiological typing methods are essential to monitor and limit the occurrence and spread of epidemic clones. Methodology: A total of sixty S. aureus isolates were collected from the Jordan University hospital in Amman-Jordan. All isolates were characterized using Staphylococcus protein A (spa) typing and pulsed-field gel electrophoresis (PFGE). Samples were tested for their susceptibility patterns against seven antimicrobial agents and for their potential to form biofilms. Results: spa typing showed that spa type t044 was the most common representing 28% of the isolates studied and 38% of the MRSA population. PFGE revealed fourty-six pulsotypes among the sixty tested isolates clustering similar spa types together. The predominant resistance was detected against levofloxacin, chloramphenicol and clindamycin. One MSSA isolate typed as spa t955 showed biofilm formation potential through protein deposition.. Conclusion: The study results are based on one hospital, but the findings of this and other studies conducted in the region indicate that there is an urgent need for standardized surveillances combined with the application of well-validated typing methods to assess the occurrence of MRSA and to control its spread.
Methicillin-resistant Staphylococcus aureus ST398, Italy
Emerging Infectious Diseases
S taphylococcus aureus is a major pathogen associated with serious community and hospital-acquired diseases. Methicillin-resistant S aureus 1 (MRSA) is responsible for a growing number of nosocomial infections, particularly in critically ill patients. 2,3 MRSA epidemiology seems to be changing, with MRSA strains being implicated in serious infections and nosocomial outbreaks, which appear to be disseminated globally in adult, pediatric, and neonatal intensive care units (ICUs). 4,5 The prevalence of MRSA infection varies from 5% to >50%, depending on the characteristics and size of the hospital. In Australia, 31.9% of the 2908 S aureus samples taken from 32 laboratories from all states and territories of the country were resistant BACKGROUND AND OBJECTIVES: Methicillin-resistant Staphylococcus aureus (MRSA) is a major nosocomial pathogen that causes severe morbidity and mortality in many hospitals worldwide. The aim of the present study was to assess the burden of MRSA nosocomial infection, its association with factors of interest, and its antimicrobial susceptibility. METHODS: This was a retrospective analysis of a database of all S aureus that were cultured from patients admitted to the different wards of Hospital Universiti Sains Malaysia (HUSM) over a period of 6 years. RESULTS: The MRSA infections rate was 10.0 per 1000 hospital admissions. The incidence density rate of MRSA infections during the study period was 1.8 per 1000 patient-days, with annual rates ranging from 0.95 to 3.47 per 1000 patient-days. Duration of hospitalization, previous antibiotic use, and bedside invasive procedures were significantly higher among MRSA than methicillin-sensitive S aureus patients (P>.05). The highest number of MRSA infections were found in orthopedic wards (25.3%), followed by surgical wards (18.2%) and intensive care units (ICUs) (16.4%). All MRSA isolates were resistant to erythromycin (98.0%), co-trimoxazole (94.0%) and gentamicin (92.0%). Clindamycin was the best antibiotic with only 6% resistance. All MRSA isolates were sensitive to vancomycin. CONCLUSION: The rate of nosocomial MRSA infection per 1000 admissions was higher than that in other studies. The three factors associated most significantly with acquired MRSA infections included duration of hospitalization, antibiotic use, and bedside invasive procedures. This study confirmed that vancomycin-resistant S aureus has not yet been established in HUSM.
Chemotherapy, 2021
Background: Emergence and prevalence of Methicillin-Resistant Staphylococcus aureus (MRSA) has become a major universal health concern, limiting therapeutic options. Methods: In the North side of Iran, during the years 2015 to 2017, a total number of 37 MRSA isolates, including 19 clinical isolates from hospitalized patients and 18 colonizing isolates from health care workers were identi ed from three hospitals, in Gorgan, North of Iran. Antimicrobial susceptibility test was performed using the disk diffusion method and E-test. The presence of virulence and antibiotic resistance determinants were evaluated by PCR. The genotypic characterization was further analyzed using multi-locus sequence, spa, SCCmec, and agr typing. Results: The frequency of MRSA among S. aureus isolates was 38.14% (37/97). The most frequent S. aureus resistant isolates were found to be obstinate against penicillin (98%) and gentamicin (82.5%). Additionally, the lowest resistance rates were found against daptomycin (0%), vancomycin (2.7%), and quinupristin-dalfopristin (5.4%). All MRSA isolates were susceptible to daptomycin with MIC 50 /MIC 90 of 0.25/0.5 µg/ml. One isolate belonging to the ST239-SCCmecIII/t037 clone (MIC≥16μg/ml) was resistant to vancomycin. All but one isolate that shares the ST22-SCCmec IV/t790 strain were positive for both tsst and pvl genes. The most predominant MRSA isolates (27%) were associated with the ST239-SCCmec III/t037 clone; and followed by ST239-SCCmec III/t924 (16.2%). Conclusions: In our study, circulating MRSA strains were genetically diverse with a high prevalence of the ST239-SCCmecIII/t037 clone. These ndings emphasize the need for future and continuous surveillance studies on MRSA to prevent the dissemination of multidrug resistance and existing MRSA clones in an effective manner. [2, 13]. The geographical differences in the genotypic characteristic of MRSA have been reported [2]. In Asia, there is signi cant divergence among countries and regions with respect to prevalence of MRSA; in fact, ST22-SCCmec IV/t790 and ST239-SCCmec III/t037 clones are predominant among patients in Iran [2, 14], and so is ST239-spa t037 and ST5-spa t002 in China [15]. On the other hand, in many regions in Asia [16, 17], sequence type 239 (ST239) is most prevalent, where, in UK, ST36 and ST30 are the most common types [18]. With this background, we are evaluating the molecular characteristics, antibiotic resistance patterns, and virulence genes pro les of MRSA isolates obtained from two kinds of study populations, namely hospitalized patients and health care workers (HCWs) in Gorgan, North of Iran. Methods Study Design and Sample Collection of S. aureus Isolates This cross-sectional study was conducted from January 2, 2016 to October 28, 2018 in three hospitals (total of 920-beds) in Gorgan, North of Iran. Written informed consent was obtained from all the patients or HCWs and the study protocol was approved by the Ethics Committee in Golestan University of Medical Sciences (No. 31078693122419), and was conducted in accordance with the Declaration of Helsinki. The demographic pro les of patients and HCWs were recorded. We identi ed S. aureus and MRSA in hospitalized patients and HCWs as well (Table 1). Only the rst sample of each patient was included in the study. In case of HCWs, samples were collected from both anterior nares. 302 unduplicated clinical samples (blood, urine, wound, sputum, and others) were obtained from in-patients, out of which S. aureus and MRSA were identi ed in 53 (17.5%), and 19 specimens (6.29%), respectively. Likewise, 351 unduplicated non-clinical samplings from the anterior nares of HCWs were carried out. All the samples were sent for bacterial culturing and identi cation, using Gram staining, and standard biochemical tests, such as catalase, tube coagulase, DNase test, and mannitol fermentation [19]. The identi cation process of all S. aureus isolates was con rmed by using genotypic methods for the presence of nucA, and femA genes [2, 20]. Data on department and period of hospitalization, clinical symptoms, antibiotic usages, and underlying conditions were recorded.
Jundishapur Journal of Microbiology, 2016
Background: The incidence of nosocomial Staphylococcus aureus infection is increasing annually and becoming a true global challenge. The pattern of Staphylococcus aureus protein A (spa) types in different geographic regions is diverse. Objectives: This study determined the prevalence of methicillin-resistant S. aureus and different spa types in S. aureus clinical isolates. Materials and Methods: During a six-month period, 90 S. aureus isolates were recovered from 320 clinical specimens. The in vitro susceptibility of various S. aureus isolates to 16 antibiotic discs was assessed using the Kirby-Bauer disk diffusion method. Molecular typing was carried out with S. aureus protein A typing via polymerase chain reaction. Results: The frequency of methicillin-resistant S. aureus in our study was 88.9%. Twenty-three (25.5%) isolates were positive for panton-valentine leukocidin encoding genes. S. aureus presented a high resistance rate to ampicillin (100%) and penicillin (100%). No resistance was observed to vancomycin, teicoplanin, or linezolid. The rates of resistance to the majority of antibiotics tested varied between 23.3% and 82.2%. The rate of multidrug resistance among these clinical isolates was 93.3%. The 90 S. aureus isolates were classified into five S. aureus protein A types: t037 (33.3%), t030 (22.2%), t790 (16.7%), t969 (11.1%), and t044 (7.7%). Eight (8.9%) isolates were not typable using the S. aureus protein A typing method. Conclusions: We report a high methicillin-resistant S. aureus rate in our hospital. Additionally, t030 and t037 were the predominant spa-types among hospital-associated S. aureus. Our findings emphasize the need for continuous surveillance to prevent the dissemination of multidrug resistance among different S. aureus protein A types in Iran.
BJSTR
Staphylococcus spp. it is one of the genera most frequently implicated in the etiology of hospital infections, especially in nosocomial wards. Staphylococcus aureus is one of the most frequently isolated pathogenic microorganisms in hospital infections, capable of causing septicemia and infections of the skin, respiratory system, and soft tissues. Furthermore, the spread of infections caused by the methicillin-resistant Staphylococcus aureus (MRSA) species is constantly increasing and is reaching worrying levels in various countries of the world, including Italy, in continuous and rapid expansion, even outside hospitals. In this study, strains of Staphylococcus with methicillin resistance in hospitalized patients were identified and characterized through a phenotypic and genotypic approach. In all the methicillin resistant strains analyzed, a high resistance to other classes of antibiotics tested was found, in accordance with the findings of the European Center for Disease Prevention and Control (CDC) and numerous studies at national and world level. On some isolated MRSA strains, a molecular epidemiological study was conducted to understand the origin and spread of circulating clones. All these have been identified by molecular approach aimed at genetic research and identification, by means of Multi Locus Sequence Typing (MLST), typing of the Staphylococcal Cassette Chromosome mec (SCCmec complex) and spa typing, typing of the repeated variable region of protein A. Using the MLST profile, 5 different clones of S. aureus were identified in several hospital departments, 4 of which already circulating in Italy and worldwide, while one is not yet reported in Italy. The application and deepening of these techniques have provided an overview of the spread and development of MRSA strains in the hospital setting.
RESEARCH Community Strains of Methicillin- Resistant Staphylococcus aureus as Potential Cause of
2013
aureus (CA-MRSA) strains have emerged in Uruguay. We reviewed S. aureus isolates from a large healthcare facility in Montevideo (center A) and obtained information from 3 additional hospitals on patients infected with CA-MRSA. An infection was defined as healthcare-onset if the culture was obtained>48 hours after hospital admission. At center A, the proportion of S. aureus infections caused by CA-MRSA increased from 4 % to 23 % over 2 years; the proportion caused by healthcare-associated MRSA (HA-MRSA) decreased from 25 % to 5%. Of 182 patients infected with CA-MRSA, 38 (21%) had healthcare-onset infections. Pulsed-field gel electrophoresis determined that 22 (92%) of 24 isolates were USA1100, a community strain. CA-MRSA has emerged in Uruguay and appears to have replaced HA-MRSA strains at 1 healthcare facility. In addition, CA-MRSA appears to cause healthcare-onset infections, a finding that emphasizes the need for infection control measures to prevent transmission within healt...
Isolation of Staphylococcus aureus in Purulent Infective Conditions with Special Reference to MRSA
2019
Background: Staphylococcus aureus is a pathogen worldwide with large disease burden. Methicillin resistant staphylococcus aureus (MRSA) is prevalent in hospital care settings and community. Timely diagnosis and treatment is essential to avert further complications of this infection as compared to Methicillin sensitive Staphylococcus aureus (MSSA). Aim of the study was to determine the prevalence of Methicillin-resistant Staphylococcus aureus (MRSA) from pus samples in a tertiary care hospital and to analyze the antibiotic susceptibility patterns of MRSA isolates. Methodology: A cross sectional study which was done in a tertiary care hospital from Jan 2018-June 2018. Various clinical specimens were cultured and staphylococcus aureus was isolated and identified using standard biochemical tests and CLSI guidelines. Results: Out of 1090 pus samples processed 597 were growth positive and among these 196 were gram positive. Out of 196 gram positive isolates 119 were staphylococcus aureus ...