Prevalence of extended-spectrum beta-lactamases in Proteus mirabilis in a Taiwanese university hospital, 1999 to 2005: identification of a novel CTX-M enzyme (CTX-M-66).
A total of 1574 nonduplicate Proteus mirabilis isolates collected at a Taiwanese hospital during 1999 to 2005 were analyzed for production of extended-spectrum beta-lactamases (ESBLs). Forty-four ESBL-producing isolates including 22 CTX-M-14, 18 CTX-M-3, 2 CTX-M-24, and 2 CTX-M-66 producers were detected, and the proportion of ESBL producers increased from 0.7% in 1999 to approximately 6% after 2002. CTX-M-66 is a novel variant of CTX-M ESBLs that differs from CTX-M-3 by a Ser to Asn change at amino acid position 23. Coresistances to aminoglycosides and ciprofloxacin were very common in the CTX-M-3 producers. The presence of ArmA-type or RmtB-type 16S rRNA methylase that confers high-level aminoglycoside resistance was detected in 12 CTX-M-3 producers and 4 CTX-M-14 producers. Twenty-four clones including an endemic CTX-M-14-producing clone were observed among the 44 ESBL producers by pulsed-field gel electrophoresis, suggesting that both horizontal transfer and clonal spread contributed to the increased prevalence of bla(CTX-M) in P. mirabilis.
Wu
Jiunn-Jong
JJ
Department of Medical Laboratory Science and Biotechnology, College of Medicine, National Cheng Kung University, Tainan 70101, Taiwan.
Chen
Hung-Mo
HM
Ko
Wen-Chien
WC
Wu
Hsiu-Mei
HM
Tsai
Shu-Huei
SH
Yan
Jing-Jou
JJ
D019943:Amino Acid Substitution / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics; D015373:Bacterial Typing Techniques; D016172:DNA Fingerprinting; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics; D016521:Electrophoresis, Gel, Pulsed-Field; D019353:Endemic Diseases; D022761:Gene Transfer, Horizontal; D005838:Genotype; D006761:Hospitals; D006801:Humans; D008780:Methyltransferases / Q000235:genetics; D008969:Molecular Sequence Data; D011512:Proteus Infections / Q000453:epidemiology / Q000382:microbiology; D011513:Proteus mirabilis / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D017422:Sequence Analysis, DNA; D013624:Taiwan / Q000453:epidemiology; D001618:beta-Lactamases / Q000145:classification / Q000235:genetics*
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D008780:Methyltransferases; D001618:beta-Lactamases