Antimicrobial resistance profile of Salmonella spp. isolated from raw beef meat samples collected from Karachi, Pakistan

Abstract

In order to isolate and characterize the antimicrobial profile of Salmonella spp. beef meat samples were collected from the local butcher shops (n=75) of Karachi, Pakistan. Three types of meat samples were collected viz., muscles, lymph nodes and minced meat (n=25 each). The samples were packaged aseptically and transported to laboratory within 4-6 hs of collection in cooling conditions. The samples were examined for Salmonella contamination; isolation and identification of Salmonella serovars was done using the standard procedure, while antimicrobial profile was illuminated using the disk diffusion method. The results indicated that 21.34% beef samples exhibited the Salmonella contamination. The statistical analysis exhibited a significantly higher (p< 0.05) prevalence rate in minced beef (28%) and lymph nodes (24%) as compared to the muscles (12%). The highest antimicrobial resistance was recorded against the antibiotics of penicillin group (88.5 to 93.7%), followed by the aminoglycosides (68.4 to 85.5%), tetracycline (73.9 to 78.6%), and quinolones (59.6 to 63.1%). While lowest resistance level was observed against the antibiotics of cephalosporin group (32.1 to 52.6%). Among 13 isolates of S. Pullorum, a highest number (10 isolates) showed resistance against neomycin, kanamycin and tetracycline. A total of 76.9% (10/13) isolates were recorded as multidrug resistant (MDR) resistant. Maximum number of S. Gallinarum (9/10), S. Typhi (12/14), S. Cholerasuis (8/10) and S. Enteritidis (13/15) isolates were exhibited resistance against ampicillin antibiotic. A 78.6% isolates of S. Typhi were recognized as MDR isolates. While, 80% isolates of S. Gallinarum, S. Cholerasuis and S. Enteritidis were observed as MDR isolates. From these results it could be concluded that meat sold at butcher shops of Karachi have significant level of Salmonella contamination. The Salmonella isolates exhibited highest antimicrobial resistance against the antibiotics of penicillin group, and have lowest resistance against cephalosporins. Among all isolates, 76 to 80% were exhibited as MDR organisms.