Analysis of drug resistance pattern and genes of Salmonella.spp isolated from human infections in Anhui Province / 中华预防医学杂志

ABSTRACT

Objective@#To investigate the drug resistance pattern and drug resistance genotypes of Salmonella. spp isolated from fecal specimens and anal swabs of diarrhea cases in Anhui Province.@*Methods@#The 149 strains of Salmonella.spp isolated from feces and anal swabs of diarrhea cases in Anhui Province from April to October 2017 were selected. The serotypes of Salmonella.spp were identified by slide agglutination. The susceptibility of all strains to 14 antibiotics were determined by micro-broth dilution method. Sixty of the cephalosporin-resistant antibiotics were selected. The β-lactamase encoding genes blaTEM, blaSHV, blaOXA-1, blaOXA-2, blaPER, blaCMY, blaCTX-M, and colistin resistance genes mcr-1 and mcr-2 were performed using the multi-PCR method.@*Results@#Of the 149 diarrhea cases, the median (P25, P75) of the age was 5.0 (1.1, 38.5). The 92 of them were male and 54.4% were children. Of the 149 strains of Salmonella.spp, 105 strains had different degrees of resistance to 13 antibiotics other than imipenem. The resistance rate of ampicillin was 55.0% (82/149), which was the highest. 53.0% strains (79 strains) were multidrug resistant, main of which were Salmonella typhimurium and Salmonella enteritidis. A total of 53 resistance patterns were detected, and 10 strains were resistant to ampicillin-ampicillin/sulbactam-tetracycline-chloramphenicol-cefazolin-trimethoprim/sulfamethoxazole, which was the most common resistance pattern. Among the 60 cephalosporin resistant strains, 45 strains carried blaTEM-1, 6 of which also carried blaCTX-M-14 and 3 of which also carried blaCTX-M-65. All the 32 strains carried only blaTEM-1 show resistance to ampicillin and 31 of them show resistance to cefazolin. There were 2 strains showing negative results of gene detection. mcr-1 was detected in a multidrug resistant strain.@*Conclusion@#The resistance of Salmonella.spp to ampicillin shows a serious situation in this region, and there were a number of multidrug resistant strains. The blaTEM-1 was the major drug resistance gene detected in this research. Detection of the mcr-1 suggests the emergence of surveillance to colistin resistance of Salmonella.spp in this area.