[Circulation and etiological characterization of Salmonella enterica serotype in human in Guangdong province, 2007-2016].

ABSTRACT

Objective: To understand the circulation, drug resistance and molecular characteristics of Salmonella1, 4, [5], 12 i- in human in Guangdong province. Methods:Salmonella1, 4, [5], 12 i- isolated from diarrhea patients in Guangdong during 2007-2016 were detected for drug resistance, genes and PFGE characteristics. Results: A total of 2 960 strains Salmonella1, 4, [5], 12 i - were isolated from human diarrhea cases during this period. The positive rates of the isolation increased year by year. The male to female ratio of the infection cases was 1.58∶1, and the infection mainly occurred in infants and young children. Except imipenem, Salmonella1, 4, [5], 12 i - was resistant to other 17 antibiotics to some extent. The drug resistant rates to ceftazidime, cefotaxime and ciprofloxacin increased from 2011 to 2016. Multi-drug resistance was serious, for example, the multi-drug resistant strains with ASSuT accounted for 70.62% (435/616) and the multi-drug resistant strains with ACSuGSTTm accounted for 27.11% (167/616). The lack of fljA, fljB and hin genes, as well as the retaining of iroB, STM2740, STM2757 genes, resulted in the unable expression of FljBenx gene with 8 different defection profiles. There were 934 different PFGE patterns observed in 2 347 strains, which displayed a relatively large fingerprint polymorphism. The major PFGE pattern was JPXX01. GD0226, which was found in 97 strains, accounting for 4.13% (97/2 347). The PFGE patterns in 168 Salmonella1, 4, [5], 12 i - strains were consistent with that of Salmonella typhimurium. Conclusions:Salmonella1,4,[5], 12 i - strains has become the major serotype of Salmonella that cause diarrhea in human in Guangdong. The multi-drug resistance of Salmonella1,4, [5], 12 i - was serious, and since the defection of fljA, fljB and hin genes, the expression of FljBenx protein failed. The PFGE results were diverse, which displayed polymorphism in inheritance.