Isolation and identification of β-lactamase producing Pseudomonas spp. in ready-to-eat raw vegetables

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Nguyen Thanh Trung1,2, Huong Nguyen Minh2, Pham Thi Loan1, Le Thi Hong Hao1, Ta Thi Yen1


1National Institute for Food Control, 65 Pham Than Duat Str., Hanoi, Vietnam
2Institute of Biotechnology, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet 1, Cau Giay, Hanoi, Vietnam


Contamination of antibiotic-resistant bacterial pathogens in raw food is becoming an increased health risk in numerous countries, including Vietnam where raw herbs and vegetables are used daily in many dishes as a flavor enhancer and a source of vitamin and nutrients. However, raw vegetables can also be a reservoir of various foodborne pathogens such as Pseudomonas spp. and Enterobacteriaceae. In this study, we evaluated the extent of Pseudomonas spp. contamination in 180 ready-to-eat (RTE) vegetables samples from restaurants in Hanoi, examined their antibiotic susceptibility profiles and determined the ability to produce β-lactamase enzymes of Pseudomonas spp. strains. Our results showed that 21.67 % (n = 39) of ready-to-eat vegetables samples in Hanoi were contaminated with Pseudomonas spp.. Of those, sixteen samples were determined to be β-lactamase producing strains including Pseudomonas putida, P. mendocina and P. aeruginosa. Further analysis revealed six strains (37.50 %) producing extended spectrum β-lactamase (ESBL) enzyme, five strains (31.25 %) producing ampC β-lactamase enzyme and five strain (31.25 %) producing both ESBL and ampC β-lactamases. It can be concluded that ready-to-eat vegetables in Hanoi would be a source of contamination of β-lactamase producing Pseudomonas spp. that could pose a threat to public health in the community.

food, ready-to-eat vegetables, contamination of antibiotic-resistant bacterial pathogens, Pseudomonas spp., health risks.
Nguyen Thanh Trung, Huong Nguyen Minh, Pham Thi Loan, Le Thi Hong Hao, Ta Thi Yen Isolation and identification of β-lactamase producing Pseudomonas spp. in ready-to-eat raw vegetables. Health Risk Analysis, 2020, no. 1, pp. 101–107. DOI: 10.21668/health.risk/2020.1.11.eng
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