SURVEY OF DRUG RESISTANCE IN 135 STRAINS OF SHIGELLA IN URUMQI

Objective To study the drug resistance and epidemic trend of Shigella from clinical isolated intestinal pathogenic bacteria in Xinjiang Urumqi area,and analyse the epidemiological characteristics of resistant phenotype and genotype of bacterial strain producing extended-spectrum β-lactamases( ESBLs),so as to provide the basis for clinical rational use of antibiotics. Methods One hundred and thirty-five Shigella strains were isolated and cultured by four divisions line method. The drug resistance of 23 kinds of antibiotics were tested using the Kirby-Bauer agar diffusion method; ESBLs phenotypic multiple drug resistant strains were tested by Kirby-Bauer agar confirmatory test; and the resistant genes CTX-M,SHV,TEM,etc were amplified by PCR; the sequence of PCR product,and gene subtypes were determined by comparing with those in GenBank. Results In 135 Shigella infection patients,male accounted for 53. 3%( 72 /135),female 46. 7%( 63 /135); high incidence occurred in July to August; those under the age of 25 accounted for 71. 85%( 97 /135). The drug resistance rate to ampicillin,chloramphenicol,and compound sulfamethoxazole was 91. 1%,68. 1%,and 70. 4% respectively; 43 strains( 31. 9%) were ESBLs phenotype positive. PCR amplification showed that a total of 19 strains carried CTX-M gene( 6 strains of CTX-M-1,13 strains of CTX-M-9),4 strains carried SHV gene,and 6 strains carried TEM gene. Also many subtypes were determined by sequencing. Conclusion Shigella flexneri which are the predominant bacteria in Urumqi,are highly resistant to some antibiotics,so proper selection of antibiotic for clinical therapy is necessary. CTX-M was the predominant resistant gene of ESBLs strain; and CTX-M-14,CTX-M-15,and TEM-1 were the epidemic subtype. The Shigella sonnei carrying CTX-M-24 were detected and reported for the first time in Xinjiang.