OXA-type beta-lactamases among extended-spectrum cephalosporin-resistant Pseudomonas aeruginosa isolates in a university hospital in southern Taiwan.
OBJECTIVE
Data on the epidemiology of OXA-type extended-spectrum beta (beta)-lactamases (ESBLs) are limited due to difficulty of identification by routine microbiology laboratories. We determined the prevalence rate of OXA-type beta-lactamases among extended-spectrum cephalosporin (ESC)-non-susceptible Pseudomonas aeruginosa isolates at a university hospital in southern Taiwan.


METHODS
A total of 1,294 ESC-non-susceptible P. aeruginosa isolates collected between 1989 and 1996 (n = 42) and between December 1999 and December 2002 (n = 1,252) were analyzed by polymerase chain reaction assays with primers specific for bla(OXA) genes and isoelectric focusing.


RESULTS
Forty five isolates (3.5%) were found to produce an OXA-type beta-lactamase. Overall, 2 OXA-type ESBLs, OXA-14 (n = 2) and OXA-17 (n = 35), were detected in 37 (2.9%) isolates, and the OXA-10-type narrow-spectrum beta-lactamase was found in 8 (0.6%) isolates. OXA-10 and the 2 OXA-type ESBLs were detected in 6 (14.3%) and 4 (9.5%) of 42 ESC-non-susceptible isolates collected between 1989 and 1996. OXA-10 and OXA-17 were detected in 2 (0.2%) and 33 (2.6%) of 1,252 ESC-non-susceptible isolates collected between December 1999 and December 2002.


CONCLUSIONS
These data indicate that OXA-17 was the most common OXA-type ESBL and that OXA-type beta-lactamases have decreased in ESC-non-susceptible P. aeruginosa at this hospital in recent years. Pulsed-field gel electrophoresis revealed clonal diversity among the OXA-producing isolates.
Yan
Jing-Jou
JJ
Department of Pathology, National Cheng Kung University Hospital, Tainan, Taiwan.
Tsai
Shu-Huei
SH
Chuang
Chin-Luan
CL
Wu
Jiunn-Jong
JJ
D001426:Bacterial Proteins / Q000096:biosynthesis / Q000145:classification / Q000235:genetics / Q000302:isolation & purification; D015373:Bacterial Typing Techniques; D018550:Cephalosporin Resistance; D016172:DNA Fingerprinting; D004269:DNA, Bacterial / Q000032:analysis / Q000235:genetics; D016521:Electrophoresis, Gel, Pulsed-Field; D006785:Hospitals, University; D006801:Humans; D007525:Isoelectric Focusing; D008826:Microbial Sensitivity Tests; D016133:Polymerase Chain Reaction; D011552:Pseudomonas Infections / Q000382:microbiology*; D011550:Pseudomonas aeruginosa / Q000145:classification / Q000187:drug effects* / Q000201:enzymology* / Q000235:genetics; D013624:Taiwan; D001618:beta-Lactamases / Q000096:biosynthesis* / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification
D001426:Bacterial Proteins; D004269:DNA, Bacterial; C425107:beta-lactamase OXA-10; C096781:beta-lactamase OXA-14; D001618:beta-Lactamases