title: Genotyping of community-associated methicillin resistant Staphylococcus aureus (CA-MRSA) in a tertiary care centre in Mysore, South India: ST2371-SCCmec IV emerges as the major clone.
abstract: The burden of community-associated methicillin resistant Staphylococcus aureus (CA-MRSA) is on the rise in population and clinical settings on account of the adaptability and virulence traits of this pathogen. We characterized 45 non-duplicate CA-MRSA strains implicated mainly in skin and soft tissue infections (SSTIs) in a tertiary care hospital in Mysore, South India. All the isolates were genotyped by staphylococcal cassette chromosome mec (SCCmec) typing, staphylococcal protein A (spa) typing, accessory gene regulator (agr) typing, and multi-locus sequence typing (MLST). Four sequence types (STs) belonging to three major clonal complexes (CCs) were identified among the isolates: CC22 (ST2371 and ST22), CC1 (ST772) and CC8 (ST8). The majority (53.3%) of the isolates was of the genotype ST2371-t852-SCCmec IV [sequence type-spa type-SCCmec type], followed by ST22-t852-SCCmec IV (22.2%), ST772-t657-SCCmec V (13.3%) and ST8-t008-SCCmec IV (11.1%). ST237I, a single locus variant of ST22 (EMRSA-15 clone), has not been reported previously from any of the Asian countries. Our study also documents for the first time, the appearance of ST8-SCCmec IV (USA300) strains in India. Representative strains of the STs were further analyzed by pulsed field gel electrophoresis (PFGE). agr typing detected type I or II alleles in the majority of the isolates. All the isolates were positive for the leukotoxin gene, pvl (Panton-Valentine leukocidin) and the staphylococcal enterotoxin gene cluster, egc. Interestingly, multidrug resistance (resistance to ⩾3 classes of non-beta-lactam antibiotics) was observed in 77.8% (n=35) of the isolates. The highest (75.5%) resistance was recorded for ciprofloxacin, followed by erythromycin (53.3%), and quinupristin-dalfopristin (51.1%). Inducible clindamycin-resistance was identified in 37.7% of the isolates and it was attributed to the presence of erm(A), erm(C) and a combination of erm(A) and erm(C) genes. Isolates which showed a phenotypic pattern of M(R)/L(S) (macrolide-resistance/lincosamide-sensitivity) harbored the msr(A) gene. In conclusion, we report a high rate of multidrug resistance among Indian strains of CA-MRSA and the emergence of the lineages ST2371 and ST8 in India.
authors.affiliation: Department of Studies in Microbiology, University of Mysore, Manasagangotri, Mysore, India.
authors.forename: Vineeth
authors.initials: V
authors.lastname: Rajan
authors.affiliation: Institute for Molecular Infection Biology, University of Wuerzburg, Wuerzburg, Germany.
authors.forename: Sonja M K
authors.initials: SM
authors.lastname: Schoenfelder
authors.affiliation: Institute for Molecular Infection Biology, University of Wuerzburg, Wuerzburg, Germany.
authors.forename: Wilma
authors.initials: W
authors.lastname: Ziebuhr
authors.affiliation: Department of Studies in Microbiology, University of Mysore, Manasagangotri, Mysore, India. Electronic address: shubhagopal_mysore@yahoo.com.
authors.forename: Shubha
authors.initials: S
authors.lastname: Gopal
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001427:Bacterial Toxins / Q000235:genetics; D017714:Community-Acquired Infections / Q000382:microbiology; D024881:Drug Resistance, Bacterial; D005798:Genes, Bacterial; D006801:Humans; D007194:India; D055624:Methicillin-Resistant Staphylococcus aureus / Q000235:genetics*; D058885:Multilocus Sequence Typing; D013203:Staphylococcal Infections / Q000382:microbiology*; D062606:Tertiary Care Centers
chemical_list: D000900:Anti-Bacterial Agents; D001427:Bacterial Toxins
keywords: CA-MRSA; Multi-locus sequence typing; Multidrug resistance; PVL; Pulsed field gel electrophoresis