Drug-resistant gene based genotyping for Acinetobacter baumannii in tracing epidemiological events and for clinical treatment within nosocomial settings.
BACKGROUND
Acinetobacter baumannii has emerged as an important pathogen related to serious infections and nosocomial outbreaks around the world. However, of the frequently used methods, pulsed-field gel electrophoresis (PFGE) and amplified fragment length polymorphism (AFLP) in Acinetobacter baumannii genotyping lack the direct molecular proof of drug resistance. This study was conducted to establish a typing method based on drug resistant gene identification in contrast to traditional PFGE and AFLP in the period of nosocomial epidemic or outbreak.


METHODS
From January 2005 to October 2005, twenty-seven strains of Acinetobacter species from Intensive Care Units, the Second Affiliated Hospital in Ningbo were isolated, including both epidemic and sporadic events. Susceptibility test, PFGE, AFLP and drug resistance gene typing (DRGT) were carried out to confirm the drug resistance and analyze the genotyping, respectively. PFGE was used as a reference to evaluate the typeability of DRGT and AFLP.


RESULTS
Twenty-seven strains of Acinetobacter displayed multiple antibiotic resistance and drug resistant genes, and beta-lactamase genes were detected in 85.2% strains. The result of DRGT was comparable to PFGE in Acinetobacter strains with different drug resistance though a little difference existed, and even suggested a molecular evolution course of different drug-resistant strains. AFLP showed great polymorphism between strains and had weak ability in distinguishing the drug resistance.


CONCLUSIONS
Compared to AFLP and PFGE, DRGT is useful to analyze localized molecular epidemiology of nosocomial infections and outbreaks, which would benefit clinical diagnosis and therapy.
Jin
Hui
H
Department of Epidemiology and Health Statistics, Southeast University, Nanjing, Jiangsu 210009, China. jinhuihld@gmail.com
Xu
Xiao-min
XM
Mi
Zu-huang
ZH
Mou
Yi
Y
Liu
Pei
P
D000151:Acinetobacter Infections / Q000382:microbiology*; D040981:Acinetobacter baumannii / Q000145:classification* / Q000187:drug effects* / Q000235:genetics; D054458:Amplified Fragment Length Polymorphism Analysis; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics* / Q000502:physiology; D016521:Electrophoresis, Gel, Pulsed-Field; D005838:Genotype; D008826:Microbial Sensitivity Tests; D016133:Polymerase Chain Reaction
D000900:Anti-Bacterial Agents