ABSTRACT
ABSTRACT: Several items containing residual antimicrobial agents are disposed of in dumpsites, placing a pressure on the microbial flora and a potential for development of resistance in these microorganisms. Multidrug resistance patterns and multiple antibiotic resistance index of Salmonella spp. isolated from waste dumps in Zaria Metropolis were thus assayed in this study using one hundred and twelve (112) soil samples collected from four waste dumpsites located in Sabon-Gari, Samaru, Tudun-Wada and Zaria City. Salmonella spp. were isolated by culture methods on selective media and characterized using a series of biochemical tests. The isolates were confirmed using microgen identification kits. Results were statistically analysed using percentages. The antibiotic resistance patterns were determined, using the disc-diffusion method. Ten antibiotics belonging to eight different classes, namely B-lactams, aminoglycosides, tetracycline, cephalosporins, fluoroquinolone, Nitrofurantoins, sulphonamides, and phenicols were tested. The result of the study revealed that 57.2% of the isolates exhibited multidrug resistance (MDR) taken as resistance to four or more antibiotics tested. On the other hand, all the isolates showed 100% susceptibility to Chloramphenicol (30µg) and Gentamicin (30µg) while 76.2% had Multiple Antibiotic Resistance (MAR) Index of 0.2 and above. The isolates showing resistance to the highest number of antibiotics were obtained from refuse dumpsites in Zaria City while an isolate from Sabon-Gari was found to be resistant to six antibiotics. These results could be indicative of possible disposal of these drug residues in the waste dump locations making them hot spots for development of resistance
Subject(s)
Drug Resistance, MultipleABSTRACT
Aim: This study was designed to investigate the prevalence and antibiotic resistance profile of Salmonella serovars from poultry and poultry farm-handlers. Study Design: Investigative Place and Duration of Study: Samples were analyzed at the Central Diagnostic Laboratory, National Veterinary Research Institute Vom and Department of Microbiology, Ahmadu Bello University, Zaria. This work was carried out between August 2012 and April 2013. Methodology: Samples were pre-enriched in buffered peptone water followed by selective enrichment using Selenite Faeces Broth and Rappaport-Vassilidis Broth. Isolation and identification was made by inoculating the selectively enriched sample on to Salmonella-Shigella agar, Xylose Lysine Deoxycholate agar and Brilliant Green agar followed by confirmation of presumptive colonies using different biochemical tests and analytical profile index 20 E. Polyvalent (O) and (H) Salmonella antisera were used for serotyping the Salmonella isolates. The CLSI, 2010 method was used for antimicrobial susceptibility testing Results: A prevalence rate of 10.9% was observed from the 450 samples. Serovars of Salmonella detected were S. Gallinarum 57.2%, S. Typhimurium 8.2%, S. Typhi 20.4%, S. Pullorum 6.1%, S. Enteritidis 6.1% and S. Paratyphi A 2.0%. Statistically, significant difference (p<0.05) was observed between isolates and occurrence at different sample sites. The isolates were 100% resistant to oxacillin, 96.0% to ampicillin, 93.9% tylosin, 83.7 5 ceftazidime and 63.3% oxytetracycline. Five of the isolates were 100% resistant to more than five different antibiotics. There was statistical significant difference (p<0.01) in antimicrobial resistance patterns exhibited by the serovars. However, the isolates showed sensitivity to gentamycin 100%, gendox 83.7%, ciprofloxacin 81.6% and amoxicillinclavulanic acid 57.1%. Conclusion: The study revealed emergence of multiple-drug resistant Salmonella serovars from poultry and poultry farm handlers. We therefore suggest further epidemiological studies.