International journal of environmental health research

Prevalence of multiple antibiotic-resistant Gram-negative bacteria on bagged, ready-to-eat baby spinach.

PMID 22838727


In this study, multiple antibiotic-resistant (MAR) Gram-negative bacteria (GNB) were isolated from triple-washed, bagged, ready-to-eat (RTE) baby spinach. Biochemical identification of randomly selected bacterial colonies showed the predominance of cytochrome oxidase-positive Pseudomonas species. Among the GNB, a higher prevalence of resistance was observed against cefoxitin (93.1%) followed by ampicillin (79.4%), chloramphenicol (72.6%), ceftizoxime (65.7%), aztreonam (64.9%), cefotaxime (53.6%), imipenem (38.3%), ceftazidime (33.5%), gentamicin (32.6%), tetracycline (22.2%), and ciprofloxacin (19.8%). Multiple antibiotic resistance (MAR) linked to two or more antibiotics was found in 95.3% of isolates, and resistance was transferable in the strains tested. These findings confirm the presence of MAR bacteria on RTE baby spinach and suggest that human consumption of this produce would amplify the MAR gene pool via conjugal transfer of MAR genes to commensal gut microflora and bacterial pathogens.