Veterinary World

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Research (Published online: 28-11-2016)

24. Occurrence and antimicrobial resistance of pathogenic Escherichia coli and Salmonella spp. in retail raw table eggs sold for human consumption in Enugu state, Nigeria - O. Josephine Okorie-Kanu, E. Vivienne Ezenduka, C. Onwuchokwe Okorie-Kanu, L. Chinweokwu Ugwu and U. John Nnamani

Veterinary World, 9(11): 1312-1319



   doi: 10.14202/vetworld.2016.1312-1319


O. Josephine Okorie-Kanu: Department of Veterinary Public Health and Preventive Medicine, Faculty of Veterinary Medicine, University of Nigeria, Nsukka, Enugu State, Nigeria;

E. Vivienne Ezenduka: Department of Veterinary Public Health and Preventive Medicine, Faculty of Veterinary Medicine, University of Nigeria, Nsukka, Enugu State, Nigeria;

C. Onwuchokwe Okorie-Kanu: Department of Veterinary Pathology, Michael Okpara University of Agriculture, Umudike, Abia State, Nigeria;

L. Chinweokwu Ugwu: Department of Veterinary Public Health and Preventive Medicine, Faculty of Veterinary Medicine, University of Nigeria, Nsukka, Enugu State, Nigeria;

U. John Nnamani: Department of Veterinary Public Health and Preventive Medicine, Faculty of Veterinary Medicine, University of Nigeria, Nsukka, Enugu State, Nigeria;


Received: 17-05-2016, Accepted: 24-10-2016, Published online: 28-11-2016


Corresponding author: O. Josephine Okorie-Kanu, e-mail:

Citation: Okorie-Kanu OJ, Ezenduka EV, Okorie-Kanu CO, Ugwu LC, Nnamani UJ (2016) Occurrence and antimicrobial resistance of pathogeic Escherichia coli and Salmonella spp. in retail raw table eggs sold for human consumption in Enugu state, Nigeria, Veterinary World, 9(11): 1312-1319.

Aim: This study was conducted to investigate the occurrence of pathogenic Escherichia coli and Salmonella species in retail raw table eggs sold for human consumption in Enugu State and to determine the resistance of these pathogens to antimicrobials commonly used in human and veterinary practices in Nigeria.

Materials and Methods: A total of 340 raw table eggs comprising 68 composite samples (5 eggs per composite sample) were collected from five selected farms (13 composite samples from the farms) and 10 retail outlets (55 composite samples from the retail outlets) in the study area over a period of 4-month (March-June, 2014). The eggs were screened for pathogenic E. coli and Salmonella species following standard procedures within 24 h of sample collection. Isolates obtained were subjected to in-vitro antimicrobial susceptibility test with 15 commonly used antimicrobials using the disk diffusion method.

Results: About 37 (54.4%) and 7 (10.3%) of the 68 composite samples were positive for pathogenic E. coli and Salmonella species, respectively. The shells showed significantly higher (p<0.05) contaminations than the contents for both microorganisms. The eggs from the farms showed higher contamination with pathogenic E. coli than eggs from the retail outlets while the reverse was the case for Salmonella species even though they were not significant (p>0.05). The organisms obtained showed a multiple drug resistance. They were completely resistant to nitrofurantoin, sulfamethoxazole/ trimethoprim, penicillin G and oxacillin. In addition to these, Salmonella spp. also showed 100% resistance to tetracycline. The pathogenic E. coli isolates obtained were 100% susceptible to gentamicin, neomycin, ciprofloxacin, and amoxicillin-clavulanic acid while Salmonella spp. showed 100% susceptibility to erythromycin, neomycin, and rifampicin. Both organisms showed varying degrees of resistance to streptomycin, amoxicillin, vancomycin, and doxycycline.

Conclusion: From the results of the study, it can be concluded that the raw table eggs marketed for human consumption in Enugu State, Nigeria is contaminated with pathogenic E. coli and Salmonella species that showed multiple drug resistance to antimicrobial agents commonly used in veterinary and human practice.

Keywords: antimicrobial agents, farms, pathogenic Escherichia coli, retail outlets, Salmonella species, table eggs.

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