Characterization of Piperacillin-Tazobactam-Resistant Klebsiella oxytoca Recovered from a Nosocomial OutbreakReportar como inadecuado




Characterization of Piperacillin-Tazobactam-Resistant Klebsiella oxytoca Recovered from a Nosocomial Outbreak - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.

We characterized 12 clinical isolates of Klebsiella oxytoca with the extended-spectrum β-lactamase ESBL phenotype high minimum inhibitory concentration MIC values of ceftriaxone recovered over 9 months at a university hospital in Japan. To determine the clonality of the isolates, we used pulsed-field gel electrophoresis PFGE, multi-locus sequence typing MLST, and PCR analyses to detect blaRBI, which encodes the β-lactamase RbiA, OXY-2-4 with overproduce-type promoter. Moreover, we performed the isoelectric focusing IEF of β-lactamases, and the determination of the MICs of β-lactams including piperacillin-tazobactam for 12 clinical isolates and E. coli HB101 with pKOB23, which contains blaRBI, by the agar dilution method. Finally, we performed the initial screening and phenotypic confirmatory tests for ESBLs. Each of the 12 clinical isolates had an identical PFGE pulsotype and MLST sequence type ST9. All 12 clinical isolates harbored identical blaRBI. The IEF revealed that the clinical isolate produced only one β-lactamase. E. coli HB101 pKOB23 and all 12 isolates demonstrated equally resistance to piperacillin-tazobactam MICs, >128 μg-ml. The phenotypic confirmatory test after the initial screening test for ESBLs can discriminate β-lactamase RbiA-producing K. oxytoca from β-lactamase CTX-M-producing K. oxytoca. Twelve clinical isolates of K. oxytoca, which were recovered from an outbreak at one university hospital, had identical genotypes and produced β-lactamase RbiA that conferred resistance to piperacillin-tazobactam. In order to detect K. oxytoca isolates that produce RbiA to promote research concerning β-lactamase RbiA-producing K. oxytoca, the phenotypic confirmatory test after the initial screening test for ESBLs would be useful.



Autor: Ai Fujita, Kouji Kimura , Satoru Yokoyama, Wanchun Jin, Jun-ichi Wachino, Keiko Yamada, Hiroyuki Suematsu, Yuka Yamagishi, Hirosh

Fuente: http://plos.srce.hr/



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