scholarly journals Laboratory, clinical, and epidemiological aspects of coagulase-negative staphylococci.

1988 ◽  
Vol 1 (3) ◽  
pp. 281-299 ◽  
Author(s):  
M A Pfaller ◽  
L A Herwaldt
Keyword(s):  
Nosocomial Infection ◽  
Antimicrobial Susceptibility ◽  
Staphylococcus Epidermidis ◽  
Susceptibility Testing ◽  
Clinical Laboratory ◽  
Time Frame ◽  
Coagulase Negative Staphylococci ◽  
Plasmid Analysis ◽  
Routine Identification ◽  
Diagnosis Of Infection

Coagulase-negative staphylococci, particularly Staphylococcus epidermidis, are increasingly important causes of nosocomial infection. Microbiologists and clinicians no longer can afford to disregard clinical isolates of coagulase-negative staphylococci as contaminants. Accurate species identification and antimicrobial susceptibility testing, in a clinically relevant time frame, are important aids in the diagnosis and management of serious coagulase-negative staphylococcal infections. Emphasis in the clinical laboratory should be placed on the routine identification of S. epidermidis and Staphylococcus saprophyticus, with identification of other species of coagulase-negative staphylococci as clinically indicated. The application of newer techniques, such as plasmid analysis and tests for slime production and adherence, contribute to our understanding of the epidemiology and pathogenesis of coagulase-negative staphylococci and may also be helpful in establishing the diagnosis of infection.

scholarly journals Tailoring Antimicrobial Susceptibility Testing to Individual Species of Coagulase-Negative Staphylococci: Next Up, Staphylococcus epidermidis

2019 ◽  
Vol 57 (12) ◽  
Author(s):  
C. Paul Morris ◽  
Patricia J. Simner
Keyword(s):  
Antimicrobial Susceptibility ◽  
Staphylococcus Epidermidis ◽  
Susceptibility Testing ◽  
Methicillin Resistance ◽  
Antimicrobial Susceptibility Testing ◽  
Individual Species ◽  
Beta Lactam ◽  
Coagulase Negative Staphylococci ◽  
Content Type ◽  
Species Specific

ABSTRACT Accurate detection of methicillin resistance among staphylococci is vital for patient care. Methicillin resistance is most commonly mediated by acquisition of the mecA gene, which encodes an altered penicillin binding protein, PBP2a. Application of phenotypic methods to detect mecA-mediated beta-lactam resistance in staphylococci is becoming more complex as species-specific differences are identified among coagulase-negative staphylococci (CoNS). Previously, interpretative criteria and antimicrobial susceptibility testing (AST) methods specific to the CoNS group were used to evaluate Staphylococcus epidermidis. A manuscript by S. N. Naccache, K. Callan, C.-A. D. Burnham, M. A. Wallace, et al. (J Clin Microbiol 57:e00961-19, 2019, https://doi.org/10.1128/JCM.00961-19) details experiments revealing that S. epidermidis, the most common clinically isolated CoNS, requires tailored use of previously described methods and interpretive criteria to reliably identify the presence of mecA-mediated methicillin resistance.

Small-colony Variants (SCVs) of Staphylococci: A Role in Foreign Body-associated Infections

2007 ◽  
Vol 30 (9) ◽  
pp. 778-785 ◽  
Author(s):  
C. Von Eiff ◽  
K. Becker
Keyword(s):  
Foreign Body ◽  
Defense Mechanisms ◽  
Susceptibility Testing ◽  
Slow Growth ◽  
Clinical Laboratory ◽  
Coagulase Negative Staphylococci ◽  
Small Colony Variants ◽  
The Past ◽  
Small Colony ◽  
Antibacterial Chemotherapy

Staphylococci have various strategies for resisting therapy that extend beyond classic mechanisms. Clinical experience with device-associated infections as well as with infections due to small-colony variants (SCVs) clearly shows that both antibacterial chemotherapy and host defense mechanisms are often unable to eliminate the pathogens and cure these infections. Of particular interest is the fact that in the past few years an increasing number of various foreign body-related infections due to staphylococcal SCVs have been reported. In this overview, the characteristics of SCVs recovered from clinical specimens and of defined mutants displaying the SCV phenotype are described. Their slow growth and changing biochemical and physiological features represent a challenge to clinical laboratory personnel, because recovery, identification, as well as susceptibility testing of these variants need particular efforts. In addition, the reduced susceptibility to aminoglycosides and the ability of SCVs to persist intracellularly require specific attention for the treatment of these infections. Thus, special efforts to search for these variants formed by Staphylococcus aureus or by coagulase-negative staphylococci should be considered when an infection is particularly resistant to therapy, persists for a long period or fails to respond to apparently adequate therapy with antimicrobial compounds.

scholarly journals Prevalence of Antimicrobial-Resistant Pathogens in Canadian Hospitals: Results of the Canadian Ward Surveillance Study (CANWARD 2008)

2010 ◽  
Vol 54 (11) ◽  
pp. 4684-4693 ◽  
Author(s):  
George G. Zhanel ◽  
Melanie DeCorby ◽  
Heather Adam ◽  
Michael R. Mulvey ◽  
Melissa McCracken ◽  
...  
Keyword(s):  
Staphylococcus Epidermidis ◽  
Susceptibility Testing ◽  
Multidrug Resistant ◽  
Surveillance Study ◽  
Bacterial Isolates ◽  
Coagulase Negative Staphylococci ◽  
Clinical Specimens ◽  
E Coli ◽  
Polymyxin E ◽  
Resistance Rates

ABSTRACT A total of 5,282 bacterial isolates obtained between 1 January and 31 December 31 2008, inclusive, from patients in 10 hospitals across Canada as part of the Canadian Ward Surveillance Study (CANWARD 2008) underwent susceptibility testing. The 10 most common organisms, representing 78.8% of all clinical specimens, were as follows: Escherichia coli (21.4%), methicillin-susceptible Staphylococcus aureus (MSSA; 13.9%), Streptococcus pneumoniae (10.3%), Pseudomonas aeruginosa (7.1%), Klebsiella pneumoniae (6.0%), coagulase-negative staphylococci/Staphylococcus epidermidis (5.4%), methicillin-resistant S. aureus (MRSA; 5.1%), Haemophilus influenzae (4.1%), Enterococcus spp. (3.3%), Enterobacter cloacae (2.2%). MRSA comprised 27.0% (272/1,007) of all S. aureus isolates (genotypically, 68.8% of MRSA were health care associated [HA-MRSA] and 27.6% were community associated [CA-MRSA]). Extended-spectrum β-lactamase (ESBL)-producing E. coli occurred in 4.9% of E. coli isolates. The CTX-M type was the predominant ESBL, with CTX-M-15 the most prevalent genotype. MRSA demonstrated no resistance to ceftobiprole, daptomycin, linezolid, telavancin, tigecycline, or vancomycin (0.4% intermediate intermediate resistance). E. coli demonstrated no resistance to ertapenem, meropenem, or tigecycline. Resistance rates with P. aeruginosa were as follows: colistin (polymyxin E), 0.8%; amikacin, 3.5%; cefepime, 7.2%; gentamicin, 12.3%; fluoroquinolones, 19.0 to 24.1%; meropenem, 5.6%; piperacillin-tazobactam, 8.0%. A multidrug-resistant (MDR) phenotype occurred frequently in P. aeruginosa (5.9%) but uncommonly in E. coli (1.2%) and K. pneumoniae (0.9%). In conclusion, E. coli, S. aureus (MSSA and MRSA), P. aeruginosa, S. pneumoniae, K. pneumoniae, H. influenzae, and Enterococcus spp. are the most common isolates recovered from clinical specimens in Canadian hospitals. The prevalence of MRSA was 27.0% (of which genotypically 27.6% were CA-MRSA), while ESBL-producing E. coli occurred in 4.9% of isolates. An MDR phenotype was common in P. aeruginosa.

A Microbiologic Approach to the Investigation of Bacterial Nosocomial Infection Outbreaks

1980 ◽  
Vol 1 (06) ◽  
pp. 391-400 ◽  
Author(s):  
Donald A. Goldmann ◽  
Ann B. Macone
Keyword(s):  
Nosocomial Infection ◽  
Susceptibility Testing ◽  
Resistant Bacteria ◽  
Antibiotic Susceptibility Testing ◽  
Bacterial Isolates ◽  
Infection Control Team ◽  
Antibiotic Resistant ◽  
Plasmid Analysis ◽  
Identification Of Bacteria ◽  
Bacteriocin Typing

This article details the appropriate microbiologic support that is critical to the successful investigation of nosocomial infection problems. The infection control team must have ready access to microbiologic data, and the laboratory should retain epidemiologically relevant bacterial isolates. Investigation of epidemics is facilitated by precise identification of bacteria and careful antibiotic susceptibility testing. In some situations, biotyping, serotyping, phage typing, bacteriocin typing, and other specialized techniques may be required. Plasmid analysis may be useful in the investigation of nosocomial infection problems caused by antibiotic-resistant bacteria.

Characterization of Staphylococcus epidermidis and Staphyloccocus warneri small-colony variants associated with prosthetic-joint infections

2014 ◽  
Vol 63 (2) ◽  
pp. 176-185 ◽  
Author(s):  
Agnieszka Bogut ◽  
Justyna Niedźwiadek ◽  
Maria Kozioł-Montewka ◽  
Dagmara Strzelec-Nowak ◽  
Jan Blacha ◽  
...  
Keyword(s):  
Antimicrobial Susceptibility ◽  
Staphylococcus Epidermidis ◽  
Hip Prosthesis ◽  
Joint Infection ◽  
Coagulase Negative Staphylococci ◽  
Sensitivity Testing ◽  
Small Colony Variants ◽  
Prosthetic Joint ◽  
Prosthetic Joint Infections ◽  
Small Colony

We determined the frequency of isolation of staphylococcal small-colony variants (SCVs) from 31 culture-positive patients undergoing revision of total hip prosthesis for aseptic loosening or presumed prosthetic-joint infection (PJI). We analysed auxotrophy of cultured SCVs, their antimicrobial susceptibility profiles and their biofilm-forming capacity. Eight SCV strains were cultivated from six (19 %) patients. All SCVs were coagulase-negative staphylococci (CNS) with Staphylococcus epidermidis as the predominant species; there was also one Staphylococcus warneri SCV. The SCVs were auxotrophic for haemin, with one strain additionally auxotrophic for menadione. We noted the presence of two phenotypically (differences concerning antimicrobial susceptibility) and genetically distinct SCV strains in one patient, as well as the growth of two genetically related SCVs that differed in terms of their morphology and the type of auxotrophy in another. Seven out of eight SCVs were resistant to meticillin and gentamicin. In addition, antibiotic sensitivity testing revealed three multidrug-resistant SCV–normal-morphology isolate pairs. One S. epidermidis SCV harboured icaADBC genes and was found to be a proficient biofilm producer. This paper highlights the involvement of CNS SCVs in the aetiology of PJIs, including what is believed to be the first report of a S. warneri SCV. These subpopulations must be actively sought in the routine diagnosis of implant-associated infections. Moreover, in view of the phenotypic and genetic diversity of some SCV pairs, particular attention should be paid to the investigation of all types of observed colony morphologies, and isolates should be subjected to antimicrobial susceptibility testing.

scholarly journals Correlation of Oxacillin MIC with mecAGene Carriage in Coagulase-Negative Staphylococci

2000 ◽  
Vol 38 (2) ◽  
pp. 752-754 ◽  
Author(s):  
Zafar Hussain ◽  
Luba Stoakes ◽  
Viki Massey ◽  
Deb Diagre ◽  
Viivi Fitzgerald ◽  
...  
Keyword(s):  
Staphylococcus Epidermidis ◽  
Clinical Laboratory ◽  
National Committee ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Coagulase Negative Staphylococci ◽  
Methicillin Resistant ◽  
Mueller Hinton ◽  
Mueller Hinton Agar ◽  
Agar Dilution

The National Committee for Clinical Laboratory Standards has recently changed the oxacillin breakpoint from ≥4 mg/liter to ≥0.5 mg/liter to detect methicillin-resistant coagulase-negative staphylococci (CoNS) because the previous breakpoint lacked sensitivity. To determine the correlation between the new oxacillin breakpoint and the presence of themecA gene, 493 CoNS of 11 species were tested. The presence of the mecA gene was determined by PCR, and oxacillin susceptibility was determined by the agar dilution method with Mueller-Hinton agar containing 2% NaCl and oxacillin (0.125 to 4.0 mg/liter). The new breakpoint correctly classified all CoNS strains with mecA as methicillin resistant and strains ofStaphylococcus epidermidis, S. haemolyticus, and S. hominiswithout mecA as methicillin susceptible. The breakpoint of ≥0.5 mg/liter was not specific for S. cohnii, S. lugdunensis, S. saprophyticus, S. warneri, and S. xylosus, in that it categorized 70 of 74 strains of these species withoutmecA (94.6%) as methicillin resistant. The results of this study indicate that the new oxacillin breakpoint accurately identifies strains of CoNS with mecAbut is not specific for strains of certain species of CoNS withoutmecA.

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