DETECTION OF β-LACTAMASES IN AMPICILIN RESISTANT ENTEROBACTERIACEAE ISOLATED FROM FOOD, HUMAN ANDCHICKEN FAECES IN EKITI STATE, NIGERIA

Abstract

The study was conducted to determine β-lactamase in ampicillin resistant members of the family Enterobacteriaceae isolated from food, human and chicken faecal remains in Ekiti state. A total of 530 samples were collected; 230 ready-to-eat food samples from canteens, 54 faecal remains from apparently healthy human volunteers, 142 faecal remains from sick human beings from the Federal Medical Centre, Ido-Ekiti and Ekiti State University Teaching Hospital Ado Ekiti; 45 faecal samples from white broiler and 59 faecal samples from black layers in some poultry farms in Ekiti State. All the samples were analyzed microbiologically using conventional techniques. The isolated bacteria were subjected to antibiotics susceptibility testing by disc diffusion method. Double disc synergy test was used to determine β-lactamase in ampicillin resistant bacterial isolates. The genetic basis of resistance was achieved by plasmid profiling and plasmid curing techniques. From the results, average bacterial counts were high in fried chicken with 1.64x103cfu/g and low in potato chips with 1.0 x103 cfu/g from eateries. Also, average bacterial counts were high in spaghetti with 1.76x103 cfu/g and low in “Fufu” with 1.02x103 cfu/g from local canteens in Ekiti State. Faecal samples from infected patients between age group 11 and 20years old had the highest average bacterial counts for female humans with 2.8x103cfu/g than the males with 2.0 x103 cfu/g. Also, faecal samples from apparently healthy human beings between age group 21 and 30years had highest counts for female with 2.2x103cfu/g than male with 2.0x103 cfu/g. Also, average bacterial count was high in black layers with 1.8x103 cfu/g than white broilers with 1.0x103 cfu/g. Four enteric bacteria, namely Escherichia coli, Klebsiella aerogenes, Salmonella typhi and Proteus vulgaris were isolated from all the samples and found highly resistant to Ampicillin(97.75±0.01a),but sensitive to Nitrofuratoin (82.16±0.01a), Nalixidic acid (81.53±0.01b) Gentamycin, (74.2±0.01b ),Ofloxacin (62.5±0.01c ) and Cotrimazole (60.50±001d). A total of five Proteus vulgaris isolates from black layers faecal samples and one Salmonella typhi from sick human faecal sample (infected patient) showed multi-drug resistance to 11 antibiotics. All these six isolates that showed multi-drug resistant bacteria have plasmid bands with the molecular weights ranging from 2,322base pair to 23,130base pair (bp). A total of 51 bacterial isolates from food, human and chicken (black layers) resistant to ampicillin and produced β-lactamase were analyzed for plasmid to detect and count the numbers of plasmid bands. Majority of the 51 bacterial isolates analyzed for plasmid profile were plasmid mediated. The molecular weights ranged from 2,322bp to 23,130bp. E. coli isolated from sick human beings in lane 3 has 3 bands, each band having molecular weights of 2,322 bp, 6,577 bp and 23,130 bp. Plasmid curing was used to confirm if the resistance was plasmid mediated or chromosomal. Resistance seen in Escherichia coli E7, E10 (sick human), E16, E21, E23, E24, E25 (food), P36 (apparently healthy black layer) and S43 (sick human) were chromosomally mediated while others are plasmid mediated. The results show that, extended spectrum β-lactamase (ESBL) producing bacteria can be found in food, human and chicken especially black layers in Ekiti State. Therefore personal hygiene in our local canteen and eateries, proper laboratory diagnosis for any infection, appropriate prescription of drugs should be considered, infectious disease control of every hospital should be effective and the use of antibiotics in poultry farm should be regulated in Ekiti State as this will help to monitor the trend of ESBLs infection.