The Molecular Study of Antibiotic Resistance to Quinolones in Strains Isolated in Tehran, Iran.

INTRODUCTION

is known as one of the most important causes of gastrointestinal disease in the world. Quinolones and fluoroquinolones are used successfully in the treatment of salmonellosis particularly for infections that have become resistant to several antibiotics. But non-susceptible isolates to quinolones have been reported in several countries. The data are limited about the prevalence of quinolone-resistant isolates in our country. Therefore, this study investigated the plasmid-mediated quinolone resistance genes in isolated in Children's Medical Center in Tehran during 2014-2015.

METHODS AND MATERIALS

isolates were isolated and identified using standard microbiological methods. Antibiotic susceptibility testing and screening of strains resistant to quinolones were performed according to the CLSI guidelines. The molecular investigation was done using specific primers for detection of qnr genes including: A, B and S, by polymerase chain reaction.

RESULTS

Overall, 92 (66.6%) strains were resistant to nalidixic acid. None of the strains showed resistance to ciprofloxacin. Out of the 92 nalidixic acid resistant strains, 52 (56.52%) harbored S genes, 15 strains (16.30%) had both A and S genes. Two (1.1%) isolates were positive for B gene. Twenty four (26.08%) nalidixic acid resistant isolates did not have any qnr qens.

CONCLUSION

The results of this study show high prevalence of resistance to nalidixic and qnr genes in isolates. Plasmid nature of this type of resistance poses an increased risk of dissemination of quinolone resistance between and non- isolates circulating in hospitals environments.