Isolation, Characterization, and Inactivation of From Leafy Green Vegetables and Urban Agriculture Systems.

is an emerging opportunistic pathogen that, on the one hand, causes severe nosocomial infection in immunocompromised populations with a high mortality rate and, on the other hand, is present ubiquitously in the environment. This study, for the first time to the best of our knowledge, isolated and characterized from leafy green vegetables produced by hydroponic farms and from a hydroponic farming facility in Singapore. Eleven isolates were obtained from three types of leafy green vegetables (sweet basil, kale, and parsley) and from the nutrient solution used by a hydroponic farm. The antimicrobial resistance (AMR), biofilm-forming ability, and resistance to UV and quaternary ammonium compound (QAC) treatments were investigated, as was the fate of in a simulated leafy green vegetable environment during a storage period of 6 days at different temperatures. The results showed that high population levels of could be reached on leafy green vegetables, especially after being stored at abused temperatures (>8-log CFU/ml in basil juice after 6 days storage at 20°C) and on hydroponic farming facilities, probably due to biofilm formation (8 to 9-log CFU/well in biofilms). At 4°C, was able to survive, but no growth was observed during storage in either bacteria culture media or basil juice for a period of 6 days. UV treatment, which induced substantial reductions in in both single-species and dual-species biofilms mixed with serovar Typhimurium reference strain (ATCC 14028) or self-isolated (>4-log reductions by 250 mJ/cm UV), is recommended for employment by hydroponic farms to treat their nutrient solutions and farming facilities so as to enhance microbial safety.