Polyclonal presence of non-multiresistant methicillin-resistant Staphylococcus aureus isolates carrying SCCmec IV in health care-associated infections in a hospital in Rio de Janeiro, Brazil

Abstract

Change in epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) was observed because of the emergence of infections by non-multiresistant MRSA (nMRSA) in our hospital in Rio de Janeiro, Brazil. Clinical characterization and molecular analysis of 20 nMRSA isolates recovered from 17 patients, between February 2005 and March 2006, were performed. The analysis included SCCmec (staphylococcal cassette chromosome mec), pulsed field gel electrophoresis (PFGE), multilocus restriction fragment, and multilocus sequence typing. MICs for oxacillin and vancomycin and presence of Panton-Valentine leukocidin (PVL) genes were also investigated. All but 1 of the 20 isolates presented SCCmec type IV. PFGE clustered all isolates into 9 genotypes. MIC < or = 16 microg/mL to oxacillin was found for 65% of the isolates, whereas 80% exhibited MIC of 2 microg/mL for vancomycin. PVL-encoding genes were observed in 3 isolates. Polyclonal presence of nMRSA SCCmec IV was observed in our institution, including community and health care-associated isolates, which belonged to the sequence types (STs) 1 (clonal complex [CC1]), ST5 (CC5), ST8 and ST72 (CC8), ST97 (CC97), and 2 ST singletons (SLV5 and SLV30).

Detection and characterization of an ST97-SCCmec-V community-associated meticillin-resistant Staphylococcus aureus clone in a neonatal intensive care unit and special care baby unit

“…A few isolates of ST97-CA-MRSA have been reported in the USA (Chung et al, 2004) (Schuenck et al, 2009) and, recently, Lebanon (Tokajian et al, 2010). These ST97-CA-MRSA isolates differed phenotypically and genetically from our isolates.…”

First report of the predominance of clonal complex 398 Staphylococcus aureus strains in osteomyelitis complicating diabetic foot ulcers: a national French study

“…Another animal clone, S. aureus CC97, was detected in our isolates. This clone was shown to have a better adaptation to animals than to humans and has been associated with bovine mastitis [19] with little impact on humans [20]. In the present study, the two CC97 S. aureus strains were isolated in DFOM as previously observed [21], suggesting a bone tropism of these clones of animal origin.…”

Methicillin resistance and virulence genes in invasive and nasal Staphylococcus epidermidis isolates from neonates

“…The combination of the types of ccr and mec class allowed the identification of the type of SCC mec (I to IX), and verify non-typeable isolates. The following S. aureus reference strains and clinical isolates were used as positive controls for SCC mec typing: EMRSA-3/Cordobés (SCC mec I) [28] , Mu50 (SCC mec II) [29], HU25 (SCC mec III) [24], 527a (SCC mec IV) [30] and 557a (SCC mec V) [31]. …”

“…Staphylococcus spp. reference strains used as positive controls were S. epidermidis ATCC 35984 ( aae , aap , bhp , embP , gehD , icaABD and sesI genes), S. epidermidis ATCC 12228 ( sdrF gene), S. epidermidis ATCC 14490 ( atlE and fbe genes) and a clinical isolate of S. aureus number 526a/USA300 ( arcA and opp3AB genes) [30]. …”