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