New trends in Staphylococcus aureus infections: glycopeptide resistance in hospital and methicillin resistance in the community

Hiramatsu, Kazumasa; Okuma, Keiko; Xue, Xiao; Yamamoto, Munetaka; Hori, Satoshi; Kapi, Maria

doi:10.1097/00001432-200208000-00009

Cited by 98 publications

(53 citation statements)

References 38 publications

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“…Beta-lactam antimicrobial agents are the preferred drugs for serious S. aureus infections. However, since the introduction of methicillin into clinical use, methicillin-resistant S. aureus (MRSA) strains have emerged worldwide as important nosocomial pathogens, and the prevalence of these strains in the community is now increasing substantially (6,10,18).…”

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New Real-Time PCR Assay for Rapid Detection of Methicillin- ResistantStaphylococcus aureusDirectly from Specimens Containing a Mixture of Staphylococci

et al. 2004

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Molecular methods for the rapid identification of methicillin-resistant Staphylococcus aureus (MRSA) are generally based on the detection of an S. aureus-specific gene target and the mecA gene. However, such methods cannot be applied for the direct detection of MRSA from nonsterile specimens such as nasal samples without the previous isolation, capture, or enrichment of MRSA because these samples often contain both coagulasenegative staphylococci (CoNS) and S. aureus, either of which can carry mecA. In this study, we describe a real-time multiplex PCR assay which allows the detection of MRSA directly from clinical specimens containing a mixture of staphylococci in <1 h. Five primers specific to the different staphylococcal cassette chromosome mec (SCCmec) right extremity sequences, including three new sequences, were used in combination with a primer and three molecular beacon probes specific to the S. aureus chromosomal orfX gene sequences located to the right of the SCCmec integration site. Of the 1,657 MRSA isolates tested, 1,636 (98.7%) were detected with the PCR assay, whereas 26 of 569 (4.6%) methicillin-susceptible S. aureus (MSSA) strains were misidentified as MRSA. None of the 62 nonstaphylococcal bacterial species or the 212 methicillin-resistant or 74 methicillinsusceptible CoNS strains (MRCoNS and MSCoNS, respectively) were detected by the assay. The amplification of MRSA was not inhibited in the presence of high copy numbers of MSSA, MRCoNS, or MSCoNS. The analytical sensitivity of the PCR assay, as evaluated with MRSA-negative nasal specimens containing a mixture of MSSA, MRCoNS, and MSCoNS spiked with MRSA, was ϳ25 CFU per nasal sample. This real-time PCR assay represents a rapid and powerful method which can be used for the detection of MRSA directly from specimens containing a mixture of staphylococci.

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New Real-Time PCR Assay for Rapid Detection of Methicillin- ResistantStaphylococcus aureusDirectly from Specimens Containing a Mixture of Staphylococci

et al. 2004

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“…However, recent reports suggest that it became increasingly prevalent in the community as well since the 1990s (6,8,13,31). Now, the MRSA strains designated community-acquired or community-associated MRSA (C-MRSA) are increasingly found in healthy individuals without conventional risk factors for MRSA colonization (2,11,14,26,33).…”

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Dissemination of Methicillin-Resistant Staphylococci among Healthy Japanese Children

et al. 2005

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Methicillin-resistant Staphylococcus aureus (MRSA), regarded as a tenacious pathogen in the hospital, has recently become increasingly prevalent as a community pathogen. We evaluated the prevalence and characteristics of methicillin-resistant staphylococci in the Japanese community by testing nasal samples of 818 children of five day care centers and two kindergartens in three districts. We found that methicillin-resistant staphylococci are already prevalent among healthy children. Among 818 children, 35 children (4.3%) carried MRSA and 231 children (28.2%) carried methicillin-resistant coagulase-negative staphylococci (MRC-NS). The types of staphylococcal cassette chromosome mec (SCCmec) found among 44 MRSA isolates were as follows: type IIa, 11 isolates; type IIb, 19 isolates; and type IV, 14 isolates. The type IIb SCCmec element was a new SCCmec element found in this study. Eleven (25%) strains which belonged to clonal complex 5 (CC5) carried type IIa SCCmec, and they produced type 2 coagulase and toxic shock syndrome toxin 1. They were indistinguishable from health care-associated MRSA (H-MRSA) strains in Japan, represented by strain N315. On the other hand, 33 (75%) strains, most of which belonged to CC78 or CC91, carried small SCCmec elements, such as type IIb or type IV, and they produced type 1 or type 3 coagulase and exfoliative toxin. The data indicated that MRSA clones distinct from H-MRSA have disseminated in healthy children. The fact that MRC-NS strains were prevalent in the community suggested that they might serve as a reservoir for the SCCmec element carried by MRSA strains disseminated in the community.

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“…The DNA sequences of SCCmec type IV elements from two Chicago CA-MRSA isolates were highly similar to each other in all regions except the left extremity (L-C) region (16), whose sequence differences resulted in the designation of SCCmec IV subtypes IVa and IVb. Recently, a third subtype, IVc, also with L-C region polymorphism relative to other SCCmec type IV elements, was reported among MRSA isolates from France (9) and Japan (11).…”

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“…It has been proposed that the L-C region contains unrelated genes and pseudogenes (9) and a number of unnecessary ORFs (16). Thus, this region has been termed a "junkyard" (9), a term suggesting functional insignificance.…”

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Novel Non- mecA -Containing Staphylococcal Chromosomal Cassette Composite Island Containing pbp4 and tagF Genes in a Commensal Staphylococcal Species: a Possible Reservoir for Antibiotic Resistance Islands in Staphylococcus aureus

Mongkolrattanothai

Boyle

Murphy

et al. 2004

Antimicrob Agents Chemother

110

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Among methicillin-resistant Staphylococcus aureus isolates, a staphylococcal chromosomal cassette containing the mecA gene (SCCmec) is integrated into the chromosome at a unique site. SCCmec also contains unique ccrAB recombinase genes mediating its integration and excision from the genome and is flanked by characteristic left and right direct-and inverted-repeat sequences. A few non-mecA-containing SCC elements that have the other molecular features described above have recently been described. The origin of these cassettes is not clear. We have identified two new members of the SCC family integrated within orfX in Staphylococcus epidermidis strain ATCC 12228, neither of which carries mecA. One is a 57-kb element flanked by a unique 28-bp SCC direct repeat. It was called the SCC composite island (SCC-CI) because it carries a 19-kb SCC element (SCCpbp4) nested within it. SCCpbp4 contains pbp4 and tagF genes, as well as one pair of ccrAB genes (allotype 2) flanked by classical SCC-specific terminal repeats. External to SCCpbp4, SCC-CI contains a second pair of ccrAB genes (allotype 4), three IS431 elements, and genes mediating resistance to heavy metals. Genes mediating restriction-modification that may facilitate horizontal transfer are also present within SCC-CI, both within and outside SCCpbp4. Several novel arrangements of the SCC direct and inverted repeats were identified. Several long stretches of homology with other SCCs were found within and outside SCCpbp4. In view of the fact that SCC-CI was found in a commensal species, it may represent a reservoir for sequences involved in genetic shuffling between staphylococci and may contribute to the diversity found in SCC elements.

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New trends in Staphylococcus aureus infections: glycopeptide resistance in hospital and methicillin resistance in the community

Cited by 98 publications

References 38 publications

New Real-Time PCR Assay for Rapid Detection of Methicillin- ResistantStaphylococcus aureusDirectly from Specimens Containing a Mixture of Staphylococci

New Real-Time PCR Assay for Rapid Detection of Methicillin- ResistantStaphylococcus aureusDirectly from Specimens Containing a Mixture of Staphylococci

Dissemination of Methicillin-Resistant Staphylococci among Healthy Japanese Children

Novel Non- mecA -Containing Staphylococcal Chromosomal Cassette Composite Island Containing pbp4 and tagF Genes in a Commensal Staphylococcal Species: a Possible Reservoir for Antibiotic Resistance Islands in Staphylococcus aureus

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