Drug Resistance Analysis, Esbles Detection And Mechanisms About Drug Resistance Against Cronobacter Sakazakii Strains

In this study, the standards of Clinical and Laboratory Standards Institute was introduced to evaluate nineteen strains of Cronobacter Sakazakii which were isolated from food resources for antibiotic susceptibility by disk diffusion technique. And the antibiotics we used were cefazolin, cephalothin, cefoperazone, ceftriaxone, cefuroxine, cefepime, gentamicin, tobramycin, aztreonam, ampicillin, ciprofloxacin, chloramphenicol, tetracycline, oxacillin, piperacillin and meropenem. The result was that the drug resistant rates of oxaxillin and cephalothin about the19strains of C. Sakazakii were100%and78.95%respectively. And all of the strains were sensitive to the remaining kinds of antibiotics. According to the standards of detection about ESBLs in the CLSI, we adopted disk diffusion technique to detect the ESBLs in the19strains of C. Sakazakii. The results showed that there were no ESBLs in the strains. Meanwhile, the same results were also found by means of PCR, in which total ten pairs of primers were used for amplification, and these primers were designed on the basis of ESBLs belonged to the four sub-types of P-lactamases. The results above showed that C. Sakazakii isolated from foods were still sensitive to most antibiotics, and they will not threaten the clinic treatment in short term.The preliminary research focused on the mechanisms of the C. Sakazakii were made on the basis of the results about the antibiotic resistence analysis. To find the resistence genes of cephalothin, the random insertion experiment of Tn-5was introduced to the number8C. Sakazakii which manifested the most obvious ability of drug resistence to the cephalothin.108srains of muton were obtained successfully. We found5strains of mutons whose growth were suppressed obviously in the condition of250μg/mL cephalothin by means of MIC experiment. And the original number8C. Sakazakii was used as control in this expeiment.The sesults indicated that the Tn-5insertion site in the5srains involved the antibiotic genes to the cephalothin.