Microbiological and molecular detection of VIM-1 metallo beta lactamase-producing Acinetobacter baumannii.
BACKGROUND
Acinetobacter resistant to carbapenems, is one of the most frequently isolated pathogens in the hospital settings and presents a challenge to the clinician.


OBJECTIVE
to detect metallo-β-lactamase in A. baumannii by E-test and VIM-1 genes by PCR.


METHODS
A four-month prospective study was done on Forty eight carbapenem resistant A. baumannii strains that isolated from patients with different types of infection either admitted or attending to the Outpatient Clinics at King Fahd Hospital in Al-Madinah Al-Monawarah. For all collected specimens, microbiological analysis, antimicrobial susceptibility testing using disk diffusion method, metallo Beta-lactamases (MBLs) detection by E-test (Epsilometer test) and VIM-1 metallo b-lactamase detection by PCR (polymerase chain reaction) were performed.


RESULTS
Among the 48 carbapenem resistant A. baumannii isolates, 13 strains had MBL detected by E-test and among them VIM-1 gene was detected by PCR in 8 isolates but among the 35 A. baumannii isolates that did not produce MBL by E-test, VIM-1 gene was detected in 5 isolates.


CONCLUSIONS
The study revealed that specificity of the E-test is low, thus overestimating the number of MBL-positive isolates while, reduction of blaVIM-1 gene expression, revealing hidden MBL phenotypes. So, all carbapenem resistant isolates should be tested by PCR regardless of whether the conventional MBL testing is performed.
Medical Microbiology and Immunology Department, Faculty  of Medicine, Mansoura University, Egypt; Medical Laboratories Technology Department, Faculty of Applied Medical Sciences, Taibah University, Saudi Arabia. safageery@gmail.com.
S M
SM
El-Ageery
S S
SS
Al-Hazmi
D000151:Acinetobacter Infections / Q000453:epidemiology / Q000382:microbiology*; D040981:Acinetobacter baumannii / Q000187:drug effects / Q000201:enzymology / Q000235:genetics / Q000302:isolation & purification*; D000293:Adolescent; D000328:Adult; D000554:Ambulatory Care Facilities; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D015780:Carbapenems / Q000494:pharmacology; D002648:Child; D004269:DNA, Bacterial / Q000235:genetics; D024901:Drug Resistance, Multiple, Bacterial; D005260:Female; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D012529:Saudi Arabia / Q000453:epidemiology; D055815:Young Adult; D001618:beta-Lactamases / Q000235:genetics
D000900:Anti-Bacterial Agents; D015780:Carbapenems; D004269:DNA, Bacterial; C417264:VIM-1 metallo-beta-lactamase; D001618:beta-Lactamases