These authors contributed equally to the work.
Staphylococcus aureus spa type t267, clonal ancestor of bovine subclinical mastitis in India
Article first published online: 2 APR 2013
© 2013 The Society for Applied Microbiology
Journal of Applied Microbiology
Volume 114, Issue 6, pages 1604–1615, June 2013
How to Cite
Mitra, S.D., Velu, D., Bhuvana, M., Krithiga, N., Banerjee, A., Shome, R., Rahman, H., Ghosh, S.K. and Shome, B.R. (2013), Staphylococcus aureus spa type t267, clonal ancestor of bovine subclinical mastitis in India. Journal of Applied Microbiology, 114: 1604–1615. doi: 10.1111/jam.12186
- Issue published online: 17 MAY 2013
- Article first published online: 2 APR 2013
- Accepted manuscript online: 11 MAR 2013 03:14AM EST
- Manuscript Revised: 5 MAR 2013
- Manuscript Accepted: 5 MAR 2013
- Manuscript Received: 21 DEC 2012
- National Agricultural Innovation Project (NAIP)
- Indian Council of Agricultural Research. Grant Number: NAIP/Comp-4/C-30017/2008-09
- agr ;
- bovine mastitis;
- PFGE ;
- spa ;
- Staphylococcus aureus ;
- virulence factors
To evaluate the virulence determinants and genetic diversity of Staphylococcus aureus from bovine subclinical mastitis milk.
Methods and Results
PCR detection of virulence genes was performed for 173 Staph. aureus from bovine subclinical mastitis milk. Further, genetic diversity was analysed by agr and spa typing followed by pulsed field gel electrophoresis (PFGE) of selected isolates. Screening of virulence genes (n = 19) showed the adherence genes viz. fnbA, clfA, fnbB and cna in 98·8, 97·1, 68·8 and 28·3 percentage of isolates, respectively, and 80 strains (46·24%) positive for enterotoxin genes were distributed as 23 toxinotypes, of which, 5 genotypes contained a single gene and the rest comprised of multiple toxin genes. Out of agr type-1 (87·3%), 74·2 per cent belonged to the three predominant spa types. Of 27 spa types, 11 were identified for the first time. The predominant spa types were t267 (N =44), t359 (N = 42) and t6877 (N =29), which together accounts to 66·5 per cent of isolates. PFGE analysis of isolates (N = 45) covering all the spa types revealed mostly similar or closely related pulsotypes. Local emergence of spa type t6877 in herd-dependant manner was observed. spa sequence–based phylogenetic analysis suggested t267 as the ancestral clone of t359, t6877 and other spa types except two.
Heterogenous virulence profile of the isolates had no significant association with the genotype. High prevalence of agr group I reaffirms their association with persistent subclinical mastitis. The spa type t267 appears to be the ancestral clone endemic in the region causing subclinical mastitis. In addition, few new spa types have emerged in the geographic region.
Significance and Impact of Study
Gives an insight into the genetic and evolutionary behaviour of Staph. aureus associated with bovine subclinical mastitis in India. The study would pave the way for devising effective control strategy for bovine mastitis in Indian context.