Novel rearrangements in the staphylococcal cassette chromosome mec type V elements of Indian ST772 and ST672 methicillin resistant Staphylococcus aureus strains

PLoS One. 2014 Apr 10;9(4):e94293. doi: 10.1371/journal.pone.0094293. eCollection 2014.

Abstract

Staphylococcus aureus is a commensal gram positive bacteria which causes severe and non severe infections in humans and livestock. In India, ST772 is a dominant and ST672 is an emerging clone of Staphylococcus aureus. Both cause serious human diseases, and carry type V SCCmec elements. The objective of this study was to characterize SCCmec type V elements of ST772 and ST672 because the usual PCR methods did not amplify all primers specific to the type. Whole genome sequencing analysis of seven ST772 and one ST672 S. aureus isolates revealed that the SCCmec elements of six of the ST772 isolates were the smallest of the extant type V elements and in addition have several other novel features. Only one ST772 isolate and the ST672 isolate carried bigger SCCmec cassettes which were composites carrying multiple ccrC genes. These cassettes had some similarities to type V SCCmec element from M013 isolate (ST59) from Taiwan in certain aspects. SCCmec elements of all Indian isolates had an inversion of the mec complex, similar to the bovine SCCmec type X. This study reveals that six out of seven ST772 S. aureus isolates have a novel type V (5C2) SCCmec element while one each of ST772 and ST672 isolates have a composite SCCmec type V element (5C2&5) formed by the integration of type V SCCmec into a MSSA carrying a SCC element, in addition to the mec gene complex inversions and extensive recombinations.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Algorithms
  • Animals
  • Cattle
  • Cluster Analysis
  • DNA Primers
  • DNA, Bacterial
  • Drug Resistance, Bacterial
  • Gene Rearrangement*
  • Genome, Bacterial
  • Humans
  • India
  • Methicillin-Resistant Staphylococcus aureus / genetics*
  • Models, Genetic
  • Oligonucleotide Array Sequence Analysis
  • Open Reading Frames
  • Recombination, Genetic
  • Sequence Alignment
  • Sequence Analysis, DNA

Substances

  • DNA Primers
  • DNA, Bacterial

Grant support

This work has been made possible through a Department of Biotechnology grant (BT/IN/New Indigo/16/GA/2010) and Swedish International Development Agency grant to GA. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.