Microbiology Research Journal International

Aims: Emergence of antibiotic resistance in bacterial strains has always remained a crucial concern. Mutations in antibiotic target sites, over expression of efflux pump are the major modes of development of bacterial antibiotic resistances. The present study was conducted to determine antibiotic resistance and role of efflux pumps in fluoroquinolone resistance by using efflux pump inhibitors.
Place and Duration of Study: The Research was conducted during June 2011 to March 2012 at Department of Biotechnology, Kurukshetra University, Kurukshetra, Haryana – India.
Methodology: Out of 57 bacterial strains 19 were procured from collection centres (reservoirs) and 38 were isolated from dairy (n = 10) and poultry farms (n = 28) and screened against 12 antibiotics of different groups by well assay. Further, fluoroquinolone sensitive/resistant strains were tested to observe the decline in minimum inhibitory concentration (MIC) levels in the presence/absence of efflux pump inhibitors.
Results: Antibiotic resistance in tested strains was higher against nitrofurantoin, lincomycin, cefixime and chloramphenicol. Majority of the bacterial strains (94.74%) showed resistance to two or more antibiotics. Isolated bacterial strains were exhibiting more antibiotic resistance than reservoir strains indicating their exposure to antibiotics. Reduction in MIC (2-4 folds) was observed when Piperine (28.07%) or Plumbagin (19.29%) was used in combination with fluoroquinolones. The findings emphasized that majority of efflux pump inhibitors are active against Gram-positive bacteria. Overexpression of efflux pump and higher antibiotic resistance was also observed in subgroup III exhibiting resistance to combination of cefixime/nitrofurantoin.
Conclusion: Efflux mediated resistance appears to contribute significantly to fluoroquinolone resistance and multidrug resistance in organisms, which may be due to involvement of active efflux pumps of both MFS and RND Family.