Detection Of Integron Ⅰ And Drug Resistance Enes Of Multidrug Resistance Salmonella Isolated From Chickens

Salmonellosis is the general name of various diseases caused by Salmonella after the animals infected with different serotypes, while avian Salmonellosis is the general name of a large group of acute or chronic poultry diseases caused by one or more serotypes of Salmonella, including pullorum disease, fowl typhoid and chicken paratyphoid which harm breeding industry greatly. With the extensive application of antibiotics in animal infection and feedstuff, the resistance of Salmonella to antimicrobial drugs has showed steady growth for nearly20years. Especially, the emerging of Salmonella multiple drug-resistant strains has been one of concerned focus of public healthy and agricultural product security. In this research,29clinical isolates of Salmonella from Harbin were detected through susceptibility test, and13isolates were determined the multi-resist-ant strains which were resistant to two kinds or more antimicrobial agents. Furthermore, the class Ⅰ integron and some resistant genes of these isolates were detected by PCR to assay the relation among the class Ⅰ integron, some resistant genes and the resistant of19Salmonella strains from chicken to provide the theoretical basis for the prevention of Salmonella.29Salmonella strains were isolated from the suspected Salmonella in chickens by conventional methods from Harbin, and a preliminary identification of the pathogen by biochemical reactions, serotype identification by slide agglutination and serumtype of clustering by30kinds of diagnostic serum were carried out.29Salmonella strains were isolated from the suspected Salmonella in chickens by conventional methods from Harbin, and a preliminary identification of the pathogen by biochemical reactions, serotype identification by slide agglutination and serumtype of clustering by30kinds of diagnostic serum were carried out. The29isolates were classified as three kinds of serotype, which is Salmonella pullorum, Salmonella typhi and Salmonella paratyphi. The separation rate was65.5%(19/29),20.6%(6/29) and13.8%(4/29), respectively.According to the standards recommended by NCCLS, the K-B method was used to detect the sensitivity of the29clinical isolates of Salmonella to10kinds of antimicrobial agents, among which were13isolates was resistance to the two kinds or more antimicrobial agents. The resistance rates of29chicken-derived Salmonella were44.82%,31.03%,10.34%,3.44%,41.37%,0,0,37.93%,37.93%,37.93%to tetracycline, ampicillin, cefazolin, chloramphenicol, sulfamethoxazole, gentamicin, kanamycin norfloxacin, ciprofloxacin, ofloxacin. Among them,11from chickens salmonella were resistance to at least five kinds of antibiotic resistance and13multi-drug resistant isolates were Salmonella pullorum.The drug resistance genes and class Ⅰ integrons of13multi-drug resistant Salmonella were assayed by PCR to analyze the relation between these resistance genes and class Ⅰ integrated. The primers of the resistance genes and class Ⅰ integron resistance gene was designed according to the sequence published in GenBank to assay the13clinical isolates, and PCR amplification results was consistent with antibiotic sensitivity phenotype. The isolates resistant to AMP-CIP-OFL-NOR-SXT-TET usually carry blatem-1, the tetA, tetB, sul1, sul2and qnr gene. The resistance patterns which was5carried class Ⅰ integron, and8Salmonella of13carried class Ⅰ integron.Verify the mobility of the13multi-drug resistant chicken source of Salmonella in the class Ⅰ integron plasmid conjugation test results showed that:containing the class Ⅰ integron resistant by the joint recipient bacteria were detected in the class Ⅰ integrondescription of class Ⅰ integrons carrying resistance genes from plasmid as a carrier, spread between the different strains, so that the encoded antimicrobial drug resistance level pass. Resistance gene in the bonding process with the integron transfer gives the new spliced bacteria resistance.The multi-drug resistant Salmonella was successfully screened.The drug-resistance genes carried by class Ⅰ integrons was assayed by the PCR andbe proved mobile by plasmid conjugation test to provide a theoretical reference for further study of Salmonella resistance mechanisms.