Enterobacter Cloacae in Fresh Vegetables: A Potential Carrier of Antibiotic Resistances to Consumers

By Hortensia Rico, Daniel Gozalbo, Carlos Sebastia and Pilar Falomir.

Published by Food Studies: An Interdisciplinary Journal

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Facultative pathogenic enterobacteria are commonly found in water, soil and vegetables, and Enterobacter is the most common genera isolated from vegetable samples, particularly E. cloacae. The aim of this work was to determine the prevalence, and clinical resistances to antibiotics, of E. cloacae in different fresh vegetables as an indicator of their potential risk to serve as a carrier of clinical resistances to consumers. A total of 160 samples of fresh vegetables (lettuce, ruccola, lamb’s lettuce, cucumber, tomato, carrot, spinach) collected from markets in Valencia city (Spain) were analyzed by standard microbiological methods. A total of 59 isolates were obtained (37% positive samples). Only four isolates were susceptible to all agents tested. Most isolates were resistant to amoxicillin/clavulanic (51 isolates) or to ampicillin (52). Other resistances were less frequent: 11 isolates were resistant to nitrofurantoine, 5 isolates were resistant to tetracycline, 3 resistances to co-trimoxazol were found, as well as one resistance to cefotaxime and another one to streptomycin. Most isolates showed clinical resistance to several agents: resistance to two agents (amoxicillin/clavulanic and ampicillin) was found in 48 isolates; 10 isolates were resistant to 3 agents: amoxicillin/clavulanic, ampicillin and tetracycline (2 isolates), amoxicillin/clavulanic, ampicillin and nitrofurantoine (6 isolates), ampicillin, co-trimoxazole and nitrofurantoine (1 isolate) and ampicillin, nirofurantoine and tetracycline (1 isolate); one isolate showed multiresistance to four chemotherapeutic agents (amoxicillin/clavulanic,ampicilin, co-trimoxazol and tetracycline), and two isolates were resistant to five chemotherapeutic agents: amoxicillin/clavulanic, ampicillin, cefotaxime, nitrofurantoine and co-trimoxazol (one isolate), and amoxicillin/clavulanic, ampicillin, nitrofurantoine, streptomycin and tetracycline (one isolate). No resistances to ceftazidime, ciprofloxacin, and chloramphenicol were detected. These results support that E. cloacae may serve as an indicator of bacterial contamination of these fresh produce, and therefore of the potential risk for consumer health, and suggests a role for this species as a carrier of resistance determinants from farms to consumers, which may constitute an additional food safety concern.

Keywords: Fresh Vegetables, Enterobacter Cloacae, Antibiotic Resistance

Food Studies: An Interdisciplinary Journal, Volume 2, Issue 3, pp.1-7. Article: Print (Spiral Bound). Article: Electronic (PDF File; 265.575KB).

Hortensia Rico

Associate Professor, Departamento de Microbiologia y Ecologia, Universidad de Valencia, Valencia, Spain

Hortensia is an Associate Professor in the department of Microbiology and Ecology at the University of Valencia. Her teaching experience covers General, Clinical and Food Microbiology. Her research activity focused on microbial contamination of food, detection and quantification of bacterial pathogens and study of their resistance to antibiotics.

Daniel Gozalbo

Associate Professor, Departamento de Microbiologia, Universidad de Valencia, Valencia, Spain

Daniel is a full Professor in the department of Microbiology and Ecology at the University of Valencia. His teaching activity covers all areas of Microbiology. His research activity focused on fungal pathogens and, more recently, microbial contamination and food safety.

Carlos Sebastia

Assistant Professor, Departamento de Microbiologia, Universidad de Valencia, Valencia, Spain

Carlos is a pharmacist with many years of experience in the private sector of Clinical Analysis, particularly in microbial identification and antibiotic resistances. He is a regular collaborator of the department of Microbiology and Ecology at the University of Valencia.

Pilar Falomir

Assistant Professor, Departamento de Microbiologia y Ecologia, Universidad de Valencia, Valencia, Spain

Pilar is an Assistant Professor in the department of Microbiology and Ecology at the University of Valencia. Her teaching experience is in General Microbiology and Food Microbiology. Her research activity focused on microbial contamination of food and determination of resistances to antibiotics.