Genetic fingerprinting and antimicrobial susceptibility profiles of Pseudomonas aeruginosa hospital isolates in Malaysia.
OBJECTIVE
Pseudomonas aeruginosa is the third most common pathogen causing nosocomial infections. The objective of this study was to investigate the antimicrobial resistance profiles and genetic diversity of hospital isolates of P. aeruginosa and to investigate the presence of several resistance genes and integrons.


METHODS
In this retrospective study, 48 clinical isolates of P. aeruginosa from 6 public hospitals in Malaysia were analyzed by antimicrobial susceptibility test and DNA fingerprinting techniques.


RESULTS
Most of the P. aeruginosa isolates were resistant to tetracycline (73%) and chloramphenicol (60%) and, to a lesser extent, cefotaxime (40%), ceftriaxone (31%), cefoperazone (29%), ticarcillin (25%), piperacillin (23%), and imipenem (21%). Less than 20% of the isolates were resistant to ceftazidime, gentamicin, cefepime, ciprofloxacin, amikacin, piperacillin-tazobactam, and aztreonam (10%). Of the 48 isolates, 33 were multidrug resistant. Two isolates were extended-spectrum beta-lactamase (ESBL) producers using the double-disk synergy test. However, polymerase chain reaction (PCR) failed to detect any common ESBL-encoding genes in all isolates, except for bla(OXA-10) in PA7 that was found to be part of a class 1 integron-encoded aacA4-bla(IMP-9)-catB8-bla(OXA-10) gene cassette. Using PCR, class 1 integron-encoded integrases were detected in 19% of the P. aeruginosa isolates. Repetitive extragenic palindrome-PCR generated 40 different profiles (F = 0.50-1.0) and enterobacterial repetitive intergenic consensus-PCR produced 46 profiles (F = 0.51-1.0). Pulsed-field gel electrophoresis with SpeI-digested genomic DNA resulted in 45 different profiles (F = 0.50-1.00).


CONCLUSIONS
Aztreonam appeared to be the most effective agent against multidrug-resistant P. aeruginosa isolates. Sixty nine percent of the P. aeruginosa isolates analyzed were multidrug resistant and the isolates were genetically diverse.
Lim
King-Ting
KT
Microbiology Division, Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia.
Yasin
Rohani Md
RM
Yeo
Chew-Chieng
CC
Puthucheary
Savithri-Devi
SD
Balan
Ganeswrie
G
Maning
Nurahan
N
Wahab
Zubaidah Abdul
ZA
Ismail
Noraini
N
Tan
Eng-Am
EA
Mustaffa
Azizah
A
Thong
Kwai-Lin
KL
D000900:Anti-Bacterial Agents / Q000494:pharmacology; D016000:Cluster Analysis; D003428:Cross Infection / Q000382:microbiology*; D016172:DNA Fingerprinting; D024881:Drug Resistance, Bacterial; D016521:Electrophoresis, Gel, Pulsed-Field; D014644:Genetic Variation; D006801:Humans; D032023:Integrons / Q000235:genetics; D008296:Malaysia; D008826:Microbial Sensitivity Tests; D016133:Polymerase Chain Reaction; D011552:Pseudomonas Infections / Q000382:microbiology*; D011550:Pseudomonas aeruginosa / Q000187:drug effects* / Q000235:genetics* / Q000302:isolation & purification; D001618:beta-Lactamases / Q000235:genetics
D000900:Anti-Bacterial Agents; D001618:beta-Lactamases