蟑螂带染霉菌的情况及人工感染研究

The research on moulds carried by cockroach and its artiricial imfected

目的 :研究蟑螂带染的霉菌、产生黄曲霉菌及其产毒能力的变化。方法 :对蟑螂的体表和消化道进行霉菌分离、鉴定、计数及黄曲霉素产毒能力的测定 ,并用产毒的黄曲霉菌对蟑螂进行人工感染实验。结果 :蟑螂带染的霉菌以曲霉为主 ,其次为青霉 ,此外还有酵母、毛霉、芽枝霉、单端孢霉、地霉、木霉等和极少数的镰刀菌。体表霉菌计数可高达 330万 /只 ,消化道计数最高达 890万 /只。对 194份蟑螂样品分离出黄曲霉菌 97株 ,经产毒测定 ,其中 8株为产毒株 ,最高产毒力可达 2 0万μg/kg。对 12 2只蟑螂用注射法人工感染产毒黄曲霉 ,其粪粒中排菌最长达 89天 ,消化道中存活 4个月以上 ,且存活在其中的黄曲霉菌产毒能力有 3.3倍的提高 ,最高可达4万μg/kg。蟑螂可带染多种霉菌 。

Objective: To research on moulds, toxigenic Aspergillus flavus carried by cockroach and its changes on toxigenic ability. Method: Isolated, identificated and counted moulds on body surface and digestive tract, and toxiganic A. flavus of captured cockroach. Determined toxigenic ability of aflatoxin and artificially infected on cockroach with toxigenic A. flavus. Results: The mainly mould carried by cockroach is Aspergillus, second is Penicillium, remaining are Yeasrs, Mucor, Cladosporium, Thichothecium, Geotrichum, Thicoderma, and the least is Fusarium etc. The number of moulds on their surfaceof each cockroach can reach 3,300,000 and 8,900,000 in digestive tract. There are 8 toxigenic A. flavus on 97 A. flavus isolated from samples of 194 cockroachs. The most toxigenic ability could reach 200,000 μg/kg in them. After injecting 122 cockroachs with toxigenic A.flavus, the mould in faeces of the cockroach remaining 89 days the longest and it could be alive for over 4 months in digestive tract, and its toxigenic ability could by 3.3 tines, reaching 40,000μg/kg the highest. Conclusion: Lots of moupds can be carryed by cockroach and their toxigenic ability of aflatoxin can be largely increased.