Epidemiological Comparison of True Methicillin-Resistant and Methicillin-Susceptible Coagulase-Negative Staphylococcal Bacteremia at Hospital Admission (original) (raw)
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The significance of coagulase-negative staphylococci bacteremia in a low resource setting
The Journal of Infection in Developing Countries, 2013
Introduction: Coagulase-negative staphylococci (CoNS) are a group of micro-organisms that are increasingly implicated as a cause of significant infection and the leading cause of bloodstream infection (BSI). One important predictor of true BSI is the isolation of CoNS from multiple blood cultures, presuming that the isolates represent the same species. Thus the objective of this study was to determine the significance of repeated CoNS isolated from blood cultures. Methodology: This was a prospective laboratory study which was initiated in June 2007 and lasted until July 2008. CoNS isolates were obtained from patients who had two positive blood cultures within a 14-day interval. CoNS were identified to the species level using an API-Staph, and antibiotics susceptibility testing was performed according to Clinical and Laboratory Standards Institute specifications. Strain relatedness was confirmed using pulsed-field gel electrophoresis. Results: During the study period, 202 CoNS-positi...
Clinical microbiology, 2019
Staphylococcus species are the predominant Gram-positive organisms obtained from blood culture samples. Its incidence in bloodstream infection among children and adults varies among. Staphylococcus aureus is regarded as pathogenic with high morbidity and mortality while coagulase-negative staphylococci (CoNS) are often regarded as a contaminant and not a true cause of bacteremia despite its rising occurrence. Predisposing factors of staphylococcal bacteremia include malnutrition, malaria, HIV/AIDS and nosocomial infections. Methicillin-resistance in Staphylococcus aureus and CoNS in bacteremia is associated with an increase in multidrug-resistant virulent strains when compared to methicillin-sensitive S. aureus or CoNS. The impact of coagulase-negative staphylococci in bacteremia is on the increase with marked clinical complications. However, this review summarizes the prevalence and epidemiology of S. aureus and CoNS in bacteremia based on research outcomes in Africa, Asia, Europe, and North America.
Journal of Antimicrobial Chemotherapy, 2014
Blood culture isolates are the cornerstone of adequate antibiotic treatment. However, many blood cultures are contaminated with bacteria residing on the skin, the most common contaminants being coagulasenegative staphylococci (CoNS). Such contaminated cultures are mostly disregarded. In this retrospective study, we show that contaminated cultures contain diagnostic information. We tested the association between resistance profiles of CoNS contaminants and those of the actual infecting bacteria isolated subsequently from the same patient, as well as their association with short-term mortality. Methods: We identified all patients in Rabin Medical Center, Israel, with positive blood cultures during 2009-12. Data included patient demographics, hospitalization records, comorbidities, blood culture results and date of death. Results: Our cohort consists of 2518 patients with 5290 blood cultures, where 1124 patients had 1664 blood cultures with CoNS contaminants. High overall CoNS resistance predicted high overall resistance of the subsequent bacterial isolates (P,0.004 and P,0.0006, for Gram-positive and-negative bacteria, respectively). Moreover, the resistance of CoNS contaminants to a specific antibiotic predicted the resistance of the subsequent bacterial isolates to that antibiotic (
Journal of clinical microbiology, 1997
We applied pulsed-field gel electrophoresis (PFGE) after SmaI digestion and random amplification of polymorphic DNA (RAPD) analysis with nine oligonucleotide primers to 146 blood culture isolates of Staphylococcus epidermidis and 25 blood culture isolates of Staphylococcus haemolyticus. These were obtained over a 12-month period from patients on the neonatal and hematology units of the Central Manchester Health Care Trust. PFGE demonstrated two clusters of isolates of S. epidermidis (type A and type B) on the neonatal ward and a single cluster (type C) on the hematology unit. Type A was represented by 10 indistinguishable isolates from nine patients, type B was represented by 20 isolates from 14 patients, and type C was represented by 26 isolates from 10 patients. Type A isolates were resistant to chloramphenicol and type C isolates were resistant to ciprofloxacin, mirroring current antibiotic usage. There was no evidence of cross infection due to S. haemolyticus. RAPD analysis, on ...
Indian Journal of Medical Microbiology, 2016
established their role in infections of the bloodstream, urinary tract, surgical sites, prosthetic devices and shunts. Another concern is the rising incidence of methicillin-resistant (MR)-CoNS in hospitalised patients. [1] Resistance to β-lactams is determined by the mecA gene harboured on a mobile genetic element, i.e., staphylococcal chromosomal cassette mec (SCCmec). [2] This not only limits treatment options but also enables transfer of these resistance elements to other Staphylococci. It is imperative that the molecular characteristics of nosocomial MRCoNS isolates from India be elucidated to understand the mobilisation and evolution of these genetic elements Introduction Recent years have seen an increased recognition of coagulase-negative staphylococci (CoNS) as agents of hospital and community acquired infections. Previously dismissed as contaminants, these pathogens have now
Brazilian Journal of Microbiology, 2011
In this paper we carried out a study about prevalence of the clinically significant coagulase negative staphylococcal (CNS) isolates found in an university hospital. Two hundred four CNS isolates from 191 patients obtained between the period of 1998 to 2002, were studied. About 27% (52/191) of the infection cases studied were confirmed as CNS-associated diseases. Blood stream infection (BSI) was the most frequent CNS associated-disease (25%; 13/52). The great majority of the BSI was verified in the Neonatal Intensive Care Unit (NICU). The analysis of the 52 patients medical history showed that 85% of the BSI was acquired in hospital. Most of the CNS nosocomial infections were associated with the use of indwelling medical devices. The incidence of methicillin-resistance among significant CNS isolates was 38%. In this study, a high percentage of exogenous contaminant was verified (60%), indicating that contamination of clinical specimens during sample collection is critical. Keim, L.S. et al. Coagulase negative Staphylococci antibiotics and the immune system (11). Although mechanisms involved in the production of biofilm are not totally clarified, bacterial products that contribute for biofilm formation are among the best-studied CNS virulence determinants, including products involved in the bacterial adhesion to solid surface and cell accumulation (2, 4, 11, 35). Many CNS also produce lipases, proteases, and other exoenzymes, which are possibly implicated with the bacterial persistence and dissemination in the host tissue (34). Although numerous species of CNS have been recognized recently, the majority is rarely pathogenic (34). Clinical studies have indicated Staphylococcus epidermidis, Staphylococcus haemolyticus, Staphylococcus warneri and Staphylococcus hominis as the most prevalent CNS in hospital infections (1, 31, 34). The emergence of antimicrobial resistant among CNS isolates is also an important factor in nosocomial infections. Furthermore, methicillin-resistant CNS (MRCNS) are crossresistant to all other ß-lactam antibiotics (28). Multiresistance has been detected in more than 80% of MRCNS hospital isolates (23). In the opposite, approximately 70% of MRCNS obtained from healthy volunteers from the community displayed higher susceptible to non-ß-lactam antibiotics (30).
Journal of Medical Microbiology, 2004
Coagulase-negative staphylococci (CNS) are frequently isolated from blood cultures, where they may be only a contaminant or the cause of bacteraemia. Determining whether an isolate of CNS represents a true CNS bacteraemia is difficult, and there is no single criterion with sufficient specificity. The aim of this study was to assess those clinical, microbiological, pathogenic and genotypic features that characterize true CNS bacteraemia. Twenty patients having two or more blood cultures positive for CNS and 20 patients with only one positive blood culture were studied. Significant bacteraemia was defined according to clinical and laboratory criteria. Incubation time for blood cultures to become positive, macroscopic appearance of colonies, species determination, biotype, susceptibility to antimicrobials, PFGE pattern and adherence capacity were all studied. Clinical bacteraemia was present in 16/20 patients with two or more positive blood cultures and in 2/ 20 patients with only one positive blood culture. A significant difference was seen in the median time to positivity between the 18 clinical bacteraemias and 22 contaminations (23 . 6 versus 29 . 2 h; P ¼ 0 . 04, Wilcoxon). There was also a significant difference between the two groups in the median absorbance of the slime test (1 . 36 versus 0 . 58; P ¼ 0 . 005). All significant bacteraemias with two or more positive blood cultures had the same species identified, the same antimicrobial susceptibility pattern and the same PFGE pattern. In two patients with true bacteraemia with only one positive blood culture, the incubation time for the culture to turn positive was ,24 h and the slime production absorbance was .2 . 5. The most useful parameters for the diagnosis of true CNS bacteraemia for patients with two positive blood cultures were incubation time until positive, species identification, antimicrobial susceptibility pattern, slime production and PFGE pattern. For patients with only one blood culture positive for CNS, the useful parameters for prediction of true bacteraemia were incubation time until positive and slime production, both of which are simple, low-cost tests.
Coagulase negative staphylococci - a fast emerging threat
JPMA. The Journal of the Pakistan Medical Association, 2015
To determine the frequency of isolation of coagulase-negative staphylococci and their resistance to methicillin over a period of time. The descriptive cross-sectional study was carried out at Army Medical College, Rawalpindi, from June 2009 to May 2012, and comprised clinical samples mostly from patients admitted to the intensive care unit. They were inoculated onto appropriate culture media depending upon the specimen. After 24-hour incubation at 35°C, coagulase-negative staphylococci were identified on the basis of colony morphology, gram staining, a positive catalase and a negative tube coagulase test.Methicillin resistance among the isolated staphylococci was determined using a 30µg Cefoxitin disc as per the Clinical and Laboratory Standards Institute protocol. Number of coagulase-negative staphylococci for each year and their methicillin resistance rates were calculated. A comparison was made with methicillin resistant staphylococcus aureus) isolated during the same period. Of ...