Identification And Typing The Legionella From Environment Water And Research For The Pathogenicity Of The Legionella Pneumophila

OBJECTIVE:Investigate the distribution state of the Legionellae in the environmental water system in Xinhui Guangdong,then genetic subtype and detect the pathogenicity character of the legionella pheumophila isolates,inorder to abtain the basic character of the legionella from the environmetal water in the disstrict,provide some valuable data for potential LD's.METHODS:(1)Collect environmental water samples in Xinhui city, culture the samples to isolate legionellae,the Gram stain,biochemical event,latex agglutination test and typing based the mip-like gene ware used to identify the isolates.(2)The further genetic subtyping were including the amplified fragment length polymorphism and typing based the mip gene,compare the methods and get the data of legionella prevailing in the district.(3)Detect the virulence gene 1vh and rtxA gene to evaluate the pathogenicity of the isolates,amplificate the magA gene of the pathogenicity island and typing its' sequence,investigate the distrubition and possible origin of the pathogenicity island of legionella pheumophila in the district.RESULTS:(1)Legionella were found in 7 spots out of 8 spots,and the cultured positive rate was 86.9%of 23 samples.32 different stains were detected,including 23 strains of L pneumophila,5 strains of L.gormann,2 strain of L.feeleii,2 strains of L.longbeachae,there are more than one Legionellae strains existed in the same water sample. (2)The obtained 24 strains of L.pneumophila can be classified 21 genetic subtypes 10 AFLP groups,and AFLP-A group was the predominance strain in this area,typing based the mip gene can classificate the 24 strais to 9 subtypes,and there is a strong relationship between the AFLP and mip gene typing.(3)Our 23 L.pneumophila strains including 21 high virulent strains and 2 low virulent strains,no finding of avirulent strain. 17 L.pneumophila strains including strains serogoup-1,strains serogroup-5 and strains serogroup-6 carried pathogenicity island magA gene,and it had different origin with mip gene.CONCLUSION:(1)The results suggest that Legionellae commonly distribute in the environmental water systems in Xinhui Guangdong. (2)Xinhui has a predominance subtype of L.pheumophila strains.(3)The isolates from Xinhui were almost high virulence strains with strong pathogenicity,they may evoke L(?)gionaires' disease outbreak.(4)The negionellae is a potential threaten to public health,necessary measure should be taken to protect the public health.