Distribution of Antibiotic Resistance Genes among Enterococcus Species Isolated from Bulk Soil of Karachi, Pakistan

Aims and Objective: Presence of Enterococcus species in the Microbiota of humans, animals and environment has been established. E. faecium and E. faecalis are the major species involved in nosocomial infections due to their ability to resist clinically important antibiotics. Soil, one of the most important environmental niches is considered as a vector for the dissemination of pathogenic bacteria to the food chain and back to the environment. This study was conducted to evaluate the presence of specific antibiotic resistance genes among Enterococcus species previously isolated and showed resistance to clinically important antibiotics from bulk soil (BS). Methodology: Multiplex PCR strategy using specific primers and thermal conditions were used for the amplification of genes responsible for antibiotic resistance. Result: The most prevalent resistance gene among the isolates was gyrA (18%) followed by parC (15%) gene. 12% and 9% isolates carried aph (3)-IIIa and aac6-aph2 genes, respectively. While TetM, TetL, aac(3)-IV were found in different frequencies. The emergence of resistance in enterococci from BS poses a substantial risk to public health, mainly owing to the heightened likelihood of treatment failures. Conclusion: This study provides a baseline data regarding presence of antibiotic-resistant genes among enterococci in BS environment that can serve as a source for further dissemination to humans and animals. Thus, continuous identification and monitoring of their incidence and emerging antibiotic resistance is important to prevent the risk of public health.