OCCURRENCE AND ANTIBIOGRAM OF ESCHERICHIA COLI O157:H7 IN LOCALLY-FERMENTED MILK (NONO) SOLD UNDER MARKET CONDITIONS IN NASARAWA STATE, NIGERIA.

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Date
2013-05
Authors
REUBEN, Rine Christopher
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Abstract
Escherichia coli O157:H7 is a newly emerging pathogen frequently associated with the consumption of food of bovine origin. Severe and life threatening human diseases caused by E. coli O157:H7 strains have been reported throughout the world. The present study evaluated the occurrence of E. coli O157:H7 in locally fermented milk (nono) sold under market conditions in Nasarawa State, Nigeria and the patterns of their antibiotic susceptibility. A total of 420 nono samples were purchased across Nasarawa State. The samples were bacteriologically analyzed in the laboratory for the presence of E. coli O157:H7 by means of cultural techniques (involving enrichment on modified tryptone soy broth and selective plating on Cefixime-Tellurite Sorbitol McConkey Agar), biochemical (Microbact 12E) and serological assays. Oxoid diagnostic kit, latex (R30959601) was used to confirm E. coli O157:H7. Confirmed isolates were further subjected to antimicrobial susceptibility test using the agar disc diffusion technique. The results of the study showed that out of 420 nono samples examined, 19 (4.5%) were contaminated with E. coli O157:H7. The highest occurrence rate (5.7%) was recorded in samples obtained from Akwanga, Wamba and Doma Local Government Areas, while Lafia and Keffi had the least occurrence rate (2.9%). With respect to the senatorial zones, Nasarawa North had the highest occurrence rate of 5.7% while the Southern zone had the least (3.6%). There was no significant difference (P>0.05) in the occurrence of E. coli O157:H7 isolated from nono samples with respect to the various Local Government Areas. Antibiotic susceptibility profiles showed that all the isolates were resistant to multiple antibiotics, except ciprofloxacin and gentamicin, resulting in nine different resistant patterns. All the 19 (100%) isolates were resistant to penicillin and tetracycline, 18 (94.7%) to erythromycin, 16 (84.2%) to amoxicillin, oxacillin and sulphamethoxazole/ trimethoprim, 13 (68.4%) to chloramphenicol and 8 (42.1%) to streptomycin; 15 (78.9%) and 17 (89.5%) of the isolates were sensitive to ciprofloxacin and gentamicin respectively. The predominant antimicrobial resistance pattern was penicillintetracycline- chloramphenicol-amoxicilin-erythromycin-oxacillin-sulphamethoxazole/ trimethoprim with the occurrence rate of 36.8% among the 19 isolates tested. Nono consumption has potential health risks to consumers not just in Nasarawa State but possibly to the nation at large. Hence proper hygiene in the processing and marketing of nono is recommended. The multiple antimicrobial resistance exhibited by E. coli O157:H7 strains in this study is an indication of possible antibiotic abuse.
Description
A THESIS SUBMITTED TO THE SCHOOL OF POST GRADUATE STUDIES AHMADU BELLO UNIVERSITY IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE AWARD OF MASTER OF SCIENCE DEGREE IN VETERINARY PUBLIC HEALTH AND PREVENTIVE MEDICINE DEPARTMENT OF VETERINARY PUBLIC HEALTH AND PREVENTIVE MEDICINE, FACULTY OF VETERINARY MEDICINE, AHMADU BELLO UNIVERSITY, ZARIA, NIGERIA
Keywords
OCCURRENCE,, ANTIBIOGRAM,, ESCHERICHIA COLI O157,, LOCALLY-FERMENTED MILK,, SOLD,, MARKET CONDITIONS,, NASARAWA STATE,, NIGERIA.
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