Overview of mecA homologues and prototype strains according to the classification of the IWG-SCC

Proposed new designation a Reported gene name (reference)Prototype strainStrain originSize (bp)% Identity b
mecA mecA (477) S. aureus N315Human (Japan)2,007100
mecA Staphylococcal strains that carry mecA Diverse hosts and sources2,00798.3–100
mecASf (465) S. fleurettii SFMP01 (CCUG 43834T)Goat (goat milk cheese)ND c 99.8
mecA1 mecA (mecA1) (463) S. sciuri subsp. carnaticum K11 d Cattle (veal leg, sliced)2,00179.1
mecAs, mecASs (465, 466) S. sciuri subsp. rodentium ATCC 700061Norway rat2,00180.2
mecA2 mecA (464) S. vitulinus CSBO8 c Horse2,00791
mecB mecAm (626) M. caseolyticus JCSC5402 c Domestic chicken (skin swab)2,02561.6
mecC mecA LGA251 (470) S. aureus LGA251 c Cattle (bulk milk sample)1,99868.7
mecC1 mecC1 (474) S. xylosus S04009Bovine mastitis1,99769.9 d
mecC2 mecC2 (475) S. saprophyticus subsp. saprophyticus 210Common shrew1,99892.9 e
  • a According to the proposed nomenclature for reporting novel mecA gene homologues (461), as follows: mec gene type, ≥70% nucleotide sequence identity with the respective prototype (hitherto described genes are mecA, mecB, and mecC); and mec gene allotypes, ≥70% to <95% nucleotide sequence identity to the respective mec gene prototype strains, designated with a numeral based on the chronological order of discovery (e.g., mecA1, mecA2, and mecC1).

  • b Unless otherwise stated, percent identity with the mecA gene in S. aureus N315.

  • ND, no data given.

  • d Percent identity with the mecA gene of S. aureus MRSA252. The gene has 93.5% nucleotide identity to mecC in S. aureus LGA251.

  • e Percent identity with the mecC sequence of S. aureus LGA251. The gene has 94.5% identity to the mecC1 sequence of S. xylosus S04009.