Carriage and Transferability of Quinolone Resistant Determinants Harboured within Environmental Isolates of Enterobacteriaceae

Nivedita Dasgupta, Nurjahan Be

Abstract

Background: Resistance to quinolone and fluroquinolone is being increasingly reported from clinical isolates but also from veterinary isolates and environmental isolates. Different plasmid mediated quinolone resistance has been reported 1998. Also, different transferable mechanism were identified, which correspond to production of qnr proteins, of the aminoglycoside acetyltransferase aac(6’)Ib-cr. Thus, the present study was undertaken to investigate occurrence as well as of quinolone resistance determinants within environmental and food isolates and their transmission dynamics. Method and findings: Samples were collected from five different sites of river, water bodies near waste disposal points and ready to eat food sample during March 2015 to August 2015. All the isolates were subjected to antimicrobial susceptibility testing for quinolone resistance and further analysed for the presence of qnr determinants and aac(6’)Ib-cr genes. Qnr and aac(6’)Ib-cr positive isolates were transformed into E.coliDH5? and horizontal transferability was determined by conjugation in streptomycinresistant E. coli recipient strain B and selecting in media containing ciprofloxacin and norfloxacin. 89.17% of the studied enterobacterial isolates were resistant to nalidixic acid followed by norfloxacin and ciprofloxacin. On performing multiplex PCR, aac(6’)Ib-cr was found in 23 isolates whereas qnrD in 7, qnrA in 5 and qnrS in 2 isolates. Only qnrS and aac(6’)Ib-cr could be transformed into E.coli DH5?. Conclusion: Identification of fluroquinolone-resistant Enterobacteria strain in the environment could be important to curb the rapid emergence and spread of FQ-resistance.

Relevant Publications in Archives of Clinical Microbiology