Prevalence and pattern of carriage of Enterobacterales isolates among food handlers in Nnewi metropolis, southeast Nigeria

Background: There is a public health concern about carriage of Enterobacterales among food workers and their potential role for transmission of food-borne illnesses. Food contamination by Enterobacterales could happen at any point of the production, processing, distribution, and preparation processes. This challenge is especially severe in developing countries like Nigeria. The objective of this study is to determine the prevalence and pattern of carriage of Enterobacterales by food handlers in Nnewi metropolis, southeast Nigeria.Methodology: This was a cross-sectional study that employed a non-probability sampling technique to recruit 178 food handlers who gave their consent and were available at the sampling area during the time of the study. Stool, urine, nasal and hand swab samples were collected from 115, 116, 120 and 173 food handlers respectively for microbiological analysis using conventional culture isolation and biochemical identification by Analytical Profile Index (API) 20E (bioMérieux). The antimicrobial susceptibility testing of the isolates was carried out on the identified isolates by the disk diffusion method. Descriptive statistics were carried out on the data.Results: Forty-four (25.4%) of the hand swab samples from 173 food handlers, 39 (32.5%) of the nasal swabs from 120 food handlers, 67 (58.3%) of the stool samples from 115 food handlers, and 29 (25.0%) of the urine samples from 116 food handlers, were positive for Enterobacterales isolates. The frequency of Enterobacterales isolation was significantly higher from stool samples compared to other samples (x2=40.032; p<0.0001), indicating a higher carriage rate in the gastrointestinal tracts of the food handlers. Across all the samples, a total of 179 Enterobacterales were isolated from the 101 (56.7%) positive food handlers. The frequency of isolation in descending order is Escherichia coli 23.2% (n=41), Klebsiella spp 18.1% (n=32), Enterobacter spp 15.3% (n=27), Citrobacter spp 10.7% (n=19), Raoultella spp 7.3% (n=13), Serratia spp 5.6% (n=10), Salmonella spp 3.9% (n=7), Kluyvera spp 3.9% (n=7), Shigella spp 2.8% (n=5), Proteus spp 2.8% (n=5), Cronobacter spp 1.7% (n=3), Erwinia spp 1.1% (n=2), Pantoea spp 1.1% (n=2), Hafnia spp 1.1% (n=2), and Yersinia spp 1.1% (n=2). The Enterobacterales isolates were resistant to cefotaxime (83.0%), amoxicillin-clavulanic acid (79.1%), cefuroxime (76.8%), cefixime (75.1%), imipenem-cilastatin (74.6%), ceftazidime-avibactam (73.3%), ceftriaxone-sulbactam (71.2%) and levofloxacin (70.5%).Conclusion: Food handlers in this study had a high carriage rate of resistant Enterobacterales pathogens, which can be transmitted to unsuspecting consumers, through the food processing and handling chains.