The Identification And Disinfectant Resistance Of Fly-Borne Bacteria In Shanghai Pudong International Airport

Port is the area with a large flow of people and commodities, the risk of disease transmission and invasion of new species exists in port area. In port area, fly is a kind of important medical insects, it carries the pathogenic bacteria closely related with many diseases like abscess, trauma, surgical infection, food poisoning. So pest control, disinfection and alien biological monitoring of port area are essential. There are many researches about antibiotic and disinfectant resistance of clinical strains before, but disinfectant resistance of pathogenic bacteria isolated from port area was rarely reported.In this thesis, combining two bacteria identification assays, Vitek2Compact and16S rRNA sequence alignment, we investigated the species and distributions of fly-borne pathogens in Shanghai Pudong International Airport. Among these isolated strains, one is Wohlfahrtiimonas chitiniclastica, a opportunistic bacteria that had not been found in China, we determined its biochemical reactions, analyzed its16s rRNA phylogeny, and its genome was sequenced. In addition, we determined the disinfectant resistance of24isolated strains and detected the resistance genes. Results of this study provide the evidences for the fly and fly-borne pathogens monitoring, and have a guiding significance to the using of disinfectants in port areas.1.Species identification of fly-borne pathogens in Shanghai Pudong International Airport.The bacteria on the body surfaces and inside the bodies of flies were isolated and cultured. The monoclonal strains were subject to automatic analysis using Vitek2Compact and16S rRNA sequence alignment. Eighteen species of bacteria (2pathogens and14opportunistic pathogens including Wohlfahrtiimonas chitiniclastica that had not been reported in China) were detected on the body surfaces of7species of flies, Fourteen species of bacteria (1pathogens and12opportunistic pathogens) were detected inside the bodies of the flies. The fly that carried the most species of bacteria was Sarcophaga misera, followed by Lucilia illustris. 2. Isolating of a Wohlfahrtiimonas chitiniclastica strain, its16S rRNA sequence alignment and phylogeny.A bacterial strain (SH04) was isolated from Chrysomya megacephala, its16S rRNA sequence was sequenced, using the blast against NCBI gene database,16S rRNA sequence of this strain has a98.86%similarity with the W. chitiniclastica type strain. There was a fulminant Sepsis case of a homeless man caused by W. chitiniclastica in Argentina. Using Mega5software, Neighbour-joining method, a Phylogenetic tree was constructed. Biochemical reactions of SH04was determined by API20NE and Vitek2assays. Results of Biochemical reactions and phylogenetic analysis demonstrate that SH04is a new record of W. chitiniclastica that isolated from the body surface of Chrysomya megacephala collected from Shanghai Pudong International Airport. Furthermore, the genome of SH04was sequenced.3.Disinfectant resistance of fly-borne bacteria and resistance gene detection.Using the broth dilution method, we determined the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of24bacterial strains (4species) to three disinfectants, the bacterial strains were isolated from the flies collected from Shanghai Pudong International Airport. Except Klebsiella pneumoniae, the rising of the strains’ MIC and MBC values to "84disinfectant" and glutaraldehyde is not obvious relative to standard strains, but several strains have high MIC and MBC values to double-stranded quaternary ammonium. We detected three disinfectant resistance genes (qacA/B,smr and qacE△1-sul1) in24strains by PCR,5strains carry qacE△1-sul1, the positive rate is20.83%.