Antimicrobial Resistance Patterns Of Escherichia Coli O157:H7 From Nigerian Fermented Milk Samples In Nasarawa State, Nigeria

Escherichia coli O157:H7 is an emerging public health concern in most countries of the world. It is an important cause of food-borne human disease. This study determined the antibiotic resistance patterns of E. coli O157:H7 from Nigerian fermented milk consumed in Nasarawa State, Nigeria. A total of 420 locallyfermented milk samples were obtained for this study. The samples were bacteriologically analyzed in the laboratory for the presence of E. coli O157:H7 by means of cultural techniques (enrichment on modified tryptone soy broth and selective plating on Cefixime-Tellurite Sorbitol Mac-Conkey Agar), biochemical (Microbact 12E) and serological assays. Oxoid diagnostic kit; latex (R30959601) was used to confirm E. coli O157:H7 respectively. 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 locally-fermented samples examined, 19 (4.5%) were contaminated with E. coli O157:H7. Among samples examined, 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%). Antibiotics susceptibility profile showed that all the isolates were resistant to multiple antibiotics, except ciprofloxacin and gentamicin, resulting in nine different resistance patterns. All the nineteen (100%) of the 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. The predominant antimicrobial resistance pattern was penicillintetracycline-chloramphenicol-amoxycilin-erythromycin-oxacillin-sulphamethoxazole/ trimethoprim with the occurrence rate of 36.8% from samples obtained from Wamba, Doma, Kokona and Keffi Local Government Areas. The consumption locally-fermented milk has potential health risks to consumers in Nasarawa State, hence proper hygiene in the process-line and marketing of this product is recommended. The multiple antimicrobial resistance exhibited by E. coli O157:H7 strains in this study is an indication of possible antibiotic