title: A simple screening test for the detection of metallo-β-lactamase-producing Pseudomonas aeruginosa and Acinetobacter in a tertiary care hospital.
abstract: Clinical utilization of carbapenems remains under threat with the emergence of   acquired carbapenemase-producing bacteria, particularly metallo-β-lactamases (MBL). Rapid   detection of MBL-producing Gram-negative bacilli is essential to prevent their widespread   dissemination. However, no standardized detection method is available for routine laboratory   use. The purpose of the study was to evaluate a chelating-agent based double disk synergic   test and disk potentiation test for MBL-producing strain detection and to determine the   isolation rate of MBL-producing Pseudomonas aeruginosa and Acinetobacter from clinical   samples in our tertiary teaching hospital. A total of 22 and 66 imipenem-resistant P. aeruginosa   and Acinetobacter isolates respectively were tested with ceftazidime (CAZ) disk by modified   double disk synergic test and disk potentiation test using ethylenediaminetetraacetic acid   (EDTA) and 2-mercaptopropionic acid (as chelating agents) to detect MBL production. The   tests were compared with EDTA-phenanthroline-imipenem (EPI) microdilution MIC test as   gold standard. MBL positive strains were detected in 17 (77.3%) P. aeruginosa and 2 (3.5%)   Acinetobacter isolates. The disk potentiation test with 2-mercaptopropionic acid (2-MPA)   dilution of 1:12 provided the most acceptable sensitivities and specificities (88.2% sensitivity   and 100% specificity in P. aeruginosa; 100% sensitivity and specificity in Acinetobacter)   compared to other screening methods used in this study. This study provided useful information   on the local prevalence of MBL-producing P. aeruginosa and Acinetobacter in our hospital.   Disc potentiation test with CAZ/2-MPA disc appears to be reliable and convenient MBL detection   method in the routine clinical laboratory.
authors.affiliation: School of Health Sciences, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia. dramilah@kk.usm.my
authors.forename: W A W
authors.initials: WA
authors.lastname: Wan Nor Amilah
authors.forename: N J
authors.initials: NJ
authors.lastname: Noor Izani
authors.forename: W K
authors.initials: WK
authors.lastname: Ng
authors.forename: J
authors.initials: J
authors.lastname: Ashraful Haq
mesh_terms: D000150:Acinetobacter / Q000201:enzymology* / Q000302:isolation & purification*; D000151:Acinetobacter Infections / Q000453:epidemiology / Q000382:microbiology; D001426:Bacterial Proteins / Q000032:analysis*; D001431:Bacteriological Techniques / Q000379:methods*; D003428:Cross Infection / Q000453:epidemiology / Q000382:microbiology; D006801:Humans; D015995:Prevalence; D011552:Pseudomonas Infections / Q000453:epidemiology / Q000382:microbiology; D011550:Pseudomonas aeruginosa / Q000201:enzymology* / Q000302:isolation & purification*; D012680:Sensitivity and Specificity; D062606:Tertiary Care Centers; D001618:beta-Lactamases / Q000032:analysis*
chemical_list: D001426:Bacterial Proteins; D001618:beta-Lactamases; C063912:carbapenemase