Journal of Food: Microbiology, Safety & Hygiene
Open Access

Abstract

Evaluation of Antimicrobial Resistance in Enterobacteriaceae and Coliforms Isolated on Farm, Packaged and Loose Vegetables in Kentucky

Avinash M Tope, Alexandra C Hitter, Shreya V Patel

Fresh produce normally carry epiphytic microorganisms; however, it can be contaminated with pathogenic bacteria. Categorized as ‘ready-to-eat’, most vegetables are consumed raw, thus, may present a food safety risk. Over the last three decades, global consumption of fresh vegetables has increased considerably, and the market has expanded by more than 20%. Concomitantly, the number of outbreaks involving fresh vegetables has increased significantly. Enterobacteriaceae members are involved in most of the bacterial outbreaks linked to fresh produce. There is a worldwide concern about the increased use of antimicrobials in agriculture. Antimicrobial resistant bacteria enter the food chain from the farm, often due to the use of animal manure. In the current study, the presence of entero-coliform bacteria and their antimicrobial susceptibilities in fresh vegetables sampled from small farms to retail was evaluated. Samples of vegetables were (i) collected directly from small farms from central Kentucky (n=59) and (ii) from four supermarkets in Frankfort, KY including loose and pre-packaged produce (n=72), analyzed for isolation of entero-coliform species. Members of the Enterobacteriaceae were detected on 25% of farm and 40% of retail produce, respectively. Approximately, 61% of the packaged produce and 19.4% of the loose produce had entero-bacterial presence, respectively. Their resistance to fourteen common antimicrobials was tested using Kirby-Bauer method. Approximately, 63% of isolates from farm and 70% of isolates from retail produce displayed resistance to at least three antimicrobial agents, while 18% of the isolates from farm and 41% from retail samples displayed resistance to at least ten antimicrobial agents. We conclude that ‘ready-to-eat’ fresh vegetables can be a source of exposure to pathogens with multiple drug resistance (MDR), defined as resistance to at-least three antimicrobial agents, leading to greater risks in immunocompromised individuals, and may serve as reservoirs for resistance gene transfers in human colon.