National Surveillance of Methicillin-Resistant
            <i>Staphylococcus aureus</i>
            in Belgian Hospitals Indicates Rapid Diversification of Epidemic Clones

Denis, Olivier; Deplano, Ariane; Nonhoff, Claire; Ryck, R. De; Mendonça, Ricardo De; Rottiers, S.; Vanhoof, R.; Struelens, Marc

doi:10.1128/aac.48.9.3625-3629.2004

Cited by 61 publications

(69 citation statements)

References 22 publications

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“…Low-level-resistant MRSA strains were referred to the reference laboratory between 1995 and 2005 to confirm oxacillin resistance. They were all mecA positive and exhibited low-level MICs to oxacillin ranging from 0.5 to 16 mg/liter, with a median of 8 mg/liter, by the agar dilution method (4,5,7). Of the last strains, five mecA-positive isolates were phenotypically categorized as oxacillin susceptible by CLSI breakpoints, with oxacillin MICs of Յ2 mg/liter and were therefore defined as "cryptic MRSA strains."…”

Section: Methodsmentioning

confidence: 99%

Evaluation of New Vitek 2 Card and Disk Diffusion Method for Determining Susceptibility of Staphylococcus aureus to Oxacillin

et al. 2008

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Detection of methicillin resistance in Staphylococcus aureus is a challenge, especially low-level resistance, which is often misdiagnosed. The aim of this study was to compare the diagnostic accuracies of the automated Vitek 2 system and disk diffusion tests, using cefoxitin and moxalactam, for the detection of methicillin resistance in S. aureus strains. Four sets of genotypically diverse isolates were selected from a national reference collection, including mecA-negative S. aureus isolates (n ‫؍‬ 56), hospital-acquired (n ‫؍‬ 88) and community-acquired (n ‫؍‬ 40) S. aureus isolates, and heterogeneous methicillin-resistant S. aureus isolates (n ‫؍‬ 29). Oxacillin susceptibility was tested by the Vitek 2 system with the AST P549 card and by disk diffusion methods using 10, 30, and 60 g cefoxitin and 30 g moxalactam. Oxacillin resistance was confirmed by PCR for the mecA gene. The overall sensitivities for oxacillin resistance detection were 97.5% for the Vitek 2 automated system, 98.7% for 60-g cefoxitin and moxalactam disk diffusion, and 99.6% for 10-and 30-g cefoxitin disks, respectively. Methicillin-susceptible S. aureus isolates were correctly reported as susceptible by all methods. The median times for methicillin testing were 7 h for the Vitek 2 system versus 24 h for disk diffusion methods. In conclusion, the cefoxitin and moxalactam disk diffusion methods and the Vitek 2 automated system are highly accurate methods for methicillin resistance detection, including a range of representative Belgian methicillin-resistant S. aureus strains and unusual strains exhibiting cryptic or low-level oxacillin resistance.

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Section: Methodsmentioning

confidence: 99%

Evaluation of New Vitek 2 Card and Disk Diffusion Method for Determining Susceptibility of Staphylococcus aureus to Oxacillin

et al. 2008

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“…Although SCCmec IV is associated with CA-MRSA (26,38), SCCmec IV is also distributed among HA-MRSA strains. For instance, SCCmec IV HA-MRSA was found in this study and found among HA-MRSA isolates from European countries and the United States with high frequency (3,6,8,33).…”

Section: Discussionmentioning

confidence: 92%

A Panton-Valentine Leucocidin (PVL)-Positive Community-Acquired Methicillin-Resistant Staphylococcus aureus (MRSA) Strain, Another Such Strain Carrying a Multiple-Drug Resistance Plasmid, and Other More-Typical PVL-Negative MRSA Strains Found in Japan

et al. 2005

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“…Interpretive criteria for use in comparing complex PFGE patterns in outbreaks have been applied to nonoutbreak situations to track the national and international dissemination of S. aureus clones (44). The use of PFGE typing with adjusted interpretation criteria for grouping patterns with Ͻ7 bands difference has been shown to correspond to clonal assignments made by other methods (12). The main criticisms of this technique for S. aureus are that PFGE may on occasion be too discriminatory for other than local or short-term epidemiological analyses, the arbitrary nature of the interpretive criteria used, and the occasional requirement for subjective analysis of complex band patterns (30).…”

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confidence: 99%

“…An automatically curated, Internet-accessible spa sequence database is now available (1). Several recent epidemiological studies have used PFGE and/or spa typing to determine the genetic relatedness of large numbers of isolates and MLST/SCCmec typing for further characterization of representative isolates of each genotype found (3,12,18).…”

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confidence: 99%

Evaluation of Molecular Typing Methods in Characterizing a European Collection of Epidemic Methicillin-Resistant Staphylococcus aureus Strains: the HARMONY Collection

Cookson¹,

et al. 2007

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We analyzed a representative sample of methicillin-resistant Staphylococcus aureus (MRSA) from 11 European countries (referred to as the HARMONY collection) using three molecular typing methods used within the HARMONY group to examine their usefulness for large, multicenter MRSA surveillance networks that use these different laboratory methodologies. MRSA isolates were collected based on their prevalence in each center and their genetic diversity, assessed by pulsed-field gel electrophoresis (PFGE). PFGE groupings (<3 bands difference between patterns) were compared to those made by sequencing of the variable repeats in the protein A gene spa and clonal designations based on multilocus sequence typing (MLST), combined with PCR analysis of the staphylococcal chromosome cassette containing the mec genes involved in methicillin resistance (SCCmec). A high level of discrimination was achieved using each of the three methodologies, with discriminatory indices between 89.5% and 91.9% with overlapping 95% confidence intervals. There was also a high level of concordance of groupings made using each method. MLST/SCCmec typing distinguished 10 groups containing at least two isolates, and these correspond to the majority of nosocomial MRSA clones described in the literature. PFGE and spa typing resolved 34 and 31 subtypes, respectively, within these 10 MRSA clones, with each subtype differing only slightly from the most common pattern using each method. The HARMONY group has found that the methods used in this study differ in their availability and affordability to European centers involved in MRSA surveillance. Here, we demonstrate that the integration of such technologies is achievable, although common protocols (such as we have developed for PFGE) may also be important, as is the use of centralized Internet sites to facilitate data analysis. PFGE and spa-typing data from analysis of MRSA isolates from the many centers that have access to the relevant equipment can be compared to reference patterns/sequences, and clonal designations can be made. In the majority of cases, these will correspond to those made by the (more expensive) method of choice-MLST/SCCmec typing-and these alternative methods can therefore be used as frontline typing systems for multicenter surveillance of MRSA.Methicillin-resistant Staphylococcus aureus (MRSA) is among the most common nosocomial pathogens globally and is generally acknowledged as the most significant due to the burden of disease it causes and to the evolution and global spread of multidrug-resistant clones. MRSA isolation rates in the United States, parts of Europe, and Asia have been increasing for more than 4 decades (36), and recent figures show that in some areas Ͼ50% of S. aureus bacteremias are caused by MRSA (4, 5, 6). Emerging intermediate, and more recently high-level (vanA-encoded), vancomycin resistance (8,22) and increasing numbers of multidrug-resistant MRSA emphasize the importance of effective antimicrobial prescribing and infection control measures that can be informed...

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National Surveillance of Methicillin-Resistant Staphylococcus aureus in Belgian Hospitals Indicates Rapid Diversification of Epidemic Clones

Abstract: Methicillin-resistant

Cited by 61 publications

References 22 publications

Evaluation of New Vitek 2 Card and Disk Diffusion Method for Determining Susceptibility of Staphylococcus aureus to Oxacillin

Evaluation of New Vitek 2 Card and Disk Diffusion Method for Determining Susceptibility of Staphylococcus aureus to Oxacillin

A Panton-Valentine Leucocidin (PVL)-Positive Community-Acquired Methicillin-Resistant Staphylococcus aureus (MRSA) Strain, Another Such Strain Carrying a Multiple-Drug Resistance Plasmid, and Other More-Typical PVL-Negative MRSA Strains Found in Japan

Evaluation of Molecular Typing Methods in Characterizing a European Collection of Epidemic Methicillin-Resistant Staphylococcus aureus Strains: the HARMONY Collection

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