Isolation of Pseudomonas Species and Extended Spectrum beta-lactamase-producing Escherichia coli from Retail Imported Mackerel Frozen Fishes Sold inAbakaliki Metropolis

Purpose: The cardinal objective of this study was to isolate, phenotypically characterize, and determine the antibiotic resistance patterns of extended spectrum beta-lactamase (ESBL)-producing Escherichia coli and Pseudomonas species from retail imported mackerel frozen fishes sold in Abakaliki metropolis. Methods: Exactly 100 mackerel frozen fish samples were collected from two selected markets within Abakaliki metropolis. They were analyzed for the presence of Escherichia coli and Pseudomonas spp. using standard microbiological techniques. Isolated E. coli and Pseudomonas spp. were screened for ESBL production using double disc synergy test and positive ESBL-producing E. coli were afterwards tested for their susceptibility to different classes of antibiotics using Kirby Bauer disc diffusion method. Results: Results showed that out of 100 fish samples analyzed, 69 (69%) were positive for Pseudomonas spp. while 21 (21%) were positive for E. coli. Out of the 21 E. coli isolated, 7 (33.3%) were confirmed to be ESBL-producers while none (0) of the Pseudomonas species isolated produced ESBL. All the ESBL-positive E. coli were completely resistant (100%) to ceftriazone, amoxicillin, cefuroxime, ticarcillin/clavanic acid, cefepime, and piperacillin. They also exhibited resistance to chloramphenicol (83.5%), and tobramycin (58.5%). Interestingly, ciprofloxacin was the most active antibiotic against the ESBL-producing E. coli isolates as they were all completely susceptible (100%) to this fluoroquinolone antibiotic. The average multiple antibiotic resistance index (MARI) of the ESBL-producing E. coli isolates was 0.84 and this depicts their multi-drug resistance traits as they were resistant to at least two different classes of antibiotics. Conclusion: This study has shown that mackerel fish might be a possible reservoir of ESBL-producing E. coli and may contribute to the spread of ESBL-producing bacterial strains to human through the food chain, thus resulting in food borne illnesses and other public health problems. Therefore, it is imperative to holistically evaluate the drift of imported fish in Abakaliki and nationwide so as to curb possible public health consequences which could arise as a result of the consumption of imported fishes harbouring ESBL-producing bacteria.