Investigation of potentially pathogenic Escherichia coli, Salmonella, and Clostridium perfringens based on virulence genes in the environment of swiftlet houses in Southern Vietnam

Aims:The swiftlet farming sector is expanding quickly, raising concerns about infections endangering swiftlet health and spreading microbes between swiftlet birds, domestic animals, and people.The goal of this study was to employ an isolation approach, followed by a PCR assay and sequencing, to identify the pathogens to determine whether common enteropathogenic bacteria such as Escherichia coli, Salmonella, and Clostridium perfringens were present in the surroundings of swiftlet housing.Methodology and results: Thirty (30) swiftlet houses were used to gather ninety samples, which included 67 faecal samples and 23 nest surface swab samples in Southern Vietnam.By isolation method, 77.61% (52/67) and 43.28% (29/67) of the faeces samples were suspected to contain E. coli and Salmonella, respectively, but not Clostridium perfringens, while all three pathogens were not detected in the nest surface samples.Subsequently, molecular identification by PCR was performed for both types of samples.For Salmonella, Salmonella enterica subsp.enterica was detected at the rate of 8.96% (6/67) in faecal samples but was not detected in nest surface swabs; three isolates were Salmonella Typhimurium serovars, and the other three isolates were Salmonella Enteritidis.Additionally, the frequencies of the virulence genes sipB, fimA, and stn were 66.67% (4/6), 100% (6/6), and 100% (6/6), respectively.For E. coli, three of the six pathotypes, including atypical EPEC, ETEC, and STEC were detected.ETEC and STEC were only present in faecal samples at rates of 47.76% (32/67) and 1.49% (1/67), respectively.EPEC was detected at the rate of 19.40% (13/67) in faeces and 26.09% (6/23) in nest surface swabs.Conclusion, significance and impact of study: Research results shows that pathogenic Salmonella and E. coli might be detected in faeces and nest surface swab samples of swiftlet birds.It suggests that swiftlet birds may serve as a reservoir for these germs.Therefore, appropriate management measures may be required to prevent potential crosstransmission among swiftlets, domestic animals, and people.