MOLECULAR CHARACTERIZATION OF BACTERIAL ISOLATES FROM RAW BEEF, CHICKEN AND FERMENTED COW MILK (NUNU) SOLD IN SOME MARKETS IN BENIN METROPOLIS

ABSTRACT

 Meat and traditional milk products are foods which are commonly consumed in Benin City. These foods are frequently displayed in the market for sale and they may be exposed to a myriad of contamination during display and vending. Using molecular methods to confirm the true identity of these isolates and ascertaining their antibiotics resistance profile is paramount. This study was conducted to examine the levels of contamination in meat and milk products sold in Benin metropolis with a view of ascertaining their antibiotics resistance profile as well as using the 16SrRNA sequence analysis to characterize them. Ten samples each of raw beef and chicken and fermented cow milk (nunu) were purchased from four different markets in Benin metropolis and analysed using standard microbiological methods. Salmonella Shigella Agar count for nunu ranged from 1.5 x 10⁴ cfu/ml to 3.5 x 10⁴ cfu/ml, beef ranged from 3.12 x 10⁴ cfu/g to 9.01 x 10⁴ cfu/g and chicken ranged from 1.01 x 10⁴ cfu/g to 9.01 x 10⁴ cfu/g. Coliform count for nunu ranged from 1.20 x 10⁴ cfu/ml to 11.02 x 10⁴ cfu/ml, beef ranged from 24.52 x 10⁴ cfu/g to 1.50 x 10⁴ cfu/g. Total aerobic plate count for nunu ranged from 1.50 ×10⁴ cfu/ml to 3.51 × 10⁴ cfu/ml, beef range from 28.50 ×10⁴ cfu/g to 10.50 ×10⁴ cfu/g, chicken ranged from 1.50 ×10⁴ cfu/g to 4.50 ×10⁴ cfu/g. A total of 148 bacterial isolates were obtained, Ekiosa market 54, Uselu market 21, Oba market and Ikpoba Hill 31 and 42 bacterial isolates, respectively. Bacillus sp. recorded the highest number of isolates 26 (16.50%), Salmonella sp. 9(5.70%), Staphylococcus aureus 20 (12.70%), E. coli and Proteus mirabilis 17 (10.80%), Pseudomonas sp. 14 (8.90%), Klebsiella sp. 23(14.60%), 22(13.90%) and 10(6.30%) were recorded for Citrobacter sp. and Shigella sp. respectively. Antibiotics susceptibility patterns of the bacterial isolates showed 100 % resistance towards Penicillin G and Clindamycin while Ampicillin and tetracycline showed 89% resistance. Molecular identification using 16sRNA confirmed the presence of Citrobacter werkmanii strain FDAARGOS_616, Proteus mirabilis strainH14320, Proteus sp strain KR 108 and Citrobacter freundi. Biofilm analysis revealed that these microorganisms were strong producers of biofilm.