Effect of Ciprofloxicine on the growth of Salmonella Species

Biotechnology

Enteric fever, a systemic infection caused by Salmonella enterica Typhi and S. enterica Paratyphi is one of the most common infections in developing countries such as India. Aside from irrational practices of antibiotic use, mutations in chromosomal genes encoding DNA gyrase and Topoisomerase IV and by plasmid mediated quinolone resistant (PMQR) genes are suggested mechanisms for the development of resistance to nalidixic acid and reduced susceptibility to ciprofloxacin. Regardless of high endemicity of enteric fever in India, there is paucity of studies on prevalence and drug-resistance of the pathogen. Therefore, this study aimed to assess the antibiotic susceptibility pattern of Salmonella isolates and determine the minimum inhibitory concentration of ciprofloxacin. A total of 50 blood samples were obtained from patients with suspected enteric fever, attending different samples collected from the hospital during March2020 to February 2021. Blood samples were inoculated immediately into BACTEC culture bottles and further processed for isolation and identification of Salmonella Typhi and S. Paratyphi. Axenic cultures of the isolates were further subjected to antimicrobial susceptibility testing (AST) by using the modified Kirby–Bauer disc diffusion method based on the guidelines by CLSI. The minimum inhibitory concentration (MIC) of ciprofloxacin was determined by agar-dilution method. Out of 50 blood cultures, 39 were positive for Salmonella spp. among which 32 (82.05%) isolates were S. Typhi and 07 (17.9%) isolates were S. Paratyphi A. The MIC value for ciprofloxacin ranged from <125-08 µg/mL in which, respectively, 1,16,6,13,1,1 and 1 of the isolates were susceptible and resistant to ciprofloxacin. Multidrugresistance (MDR) value for Salmonella Typhi and Salmonella Paratyphi were reported 6.83% and 5.12% this study. This study showed high prevalence of quinolone-resistant Salmonella spp., while there was marked re-emergence of susceptibilities to traditional first option drugs. Hence, conventional first-line-drugs and third-generation cephalosporins may find potential usage as the empirical drugs for enteric fever

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