Chromosome-encoded AmpC and CTX-M extended-spectrum ?-lactamases in clinical isolates of Proteus mirabilis from Korea.

ABSTRACT: Among 222 Proteus mirabilis clinical isolates collected from 17 hospitals in Korea in 2008, 28 (12.6%) and 8 (3.6%) isolates exhibited extended-spectrum ?-lactamase (ESBL) and AmpC phenotypes, respectively. The most common type of ESBL gene identified by PCR and sequencing experiments was bla(CTX-M-14a) (n = 12). The bla(CTX-M-90) (n = 4), bla(CTX-M-15) (n = 3), bla(CTX-M-12) (n = 3), bla(CTX-M-2) (n = 2), bla(CTX-M-14b) (n = 1), bla(TEM-52) (n = 5), and bla(SHV-12) (n = 1) genes were also detected. Eight isolates carried an AmpC ?-lactamase gene, such as bla(CMY-2) (n = 6) or bla(DHA-1) (n = 2). All bla genes encoding CTX-M-1- and CTX-M-9-type enzymes and all bla(CMY-2) genes were preceded by ISEcp1-like elements. The bla(CTX-M-2) gene found in two isolates was located on a complex class 1 integron. The bla(DHA-1) gene was preceded by a transcriptional regulator gene and was followed by phage shock protein genes. The bla(CTX-M) genes were located on the chromosome in 21 isolates. A plasmid location for the bla(CTX-M) gene was found in only four isolates: the bla(CTX-M-14a) gene was located on ?150-kbp IncA/C plasmids in three isolates and on a ?50-kbp IncN plasmid in one isolate. The bla(TEM-52) gene was located on ?50-kbp IncN plasmids in all five isolates. The AmpC ?-lactamase genes were located on the chromosome in seven of eight isolates; one isolate carried the bla(CMY-2) gene on a ?150-kbp IncA/C plasmid. Our results show that a chromosomal location of CTX-M ESBL and AmpC ?-lactamase genes in P. mirabilis is no longer an unusual phenomenon in hospital environments.

SUBMITTER: Song W 

PROVIDER: S-EPMC3067170 | biostudies-literature | 2011 Apr

REPOSITORIES: biostudies-literature