The laboratory diagnosis of Pseudomonas aeruginosa that produce metallo-ß-lactamases in a Dutch tertiary care centre.
Scand J Infect Dis
; 43(8): 596-602, 2011 Aug.
Article
in En
| MEDLINE
| ID: mdl-21506891
ABSTRACT
BACKGROUND:
The laboratory detection of Pseudomonas aeruginosa that produce metallo-ß-lactamases (MBLs) is not well defined in regions with a low prevalence of these enzymes. We report a study that developed ethylenediaminetetraacetic acid (EDTA) disk screen tests using doripenem, imipenem and meropenem and investigated the prevalence of these enzymes among clinical isolates of imipenem-resistant P. aeruginosa in Rotterdam during 2008-2009.METHODS:
Using strains with well-characterized ß-lactamases and the Clinical and Laboratory Standards Institute (CLSI) disk methodology similar to extended-spectrum ß-lactamase (ESBL) detection, inhibition zone diameters were determined in tests with doripenem, imipenem, and meropenem, alone and in combination with 370 µg of EDTA. These tests were compared with the MBL E-test. A positive test was a ≥5 mm increase in zone diameter in the presence of EDTA.RESULTS:
The imipenem EDTA disk screen test showed a sensitivity of 100% and a specificity of 90% in 96 recent clinical isolates. Imipenem in combination with doripenem performed better than imipenem alone, meropenem, and the MBL E-test (sensitivity of 100%; specificity of 95%). The majority of clinical isolates were isolated from patient respiratory specimens. Of the 96 imipenem-resistant P. aeruginosa isolated, 35 (36%) were positive for bla(VIM) genes.CONCLUSIONS:
The EDTA imipenem/doripenem disk test showed accurate and reproducible results with excellent sensitivity and specificity. It is simple to perform and interpret and can be easily introduced into the workflow of a clinical laboratory to screen for MBLs in imipenem-resistant P. aeruginosa. Due to its high specificity the test is also suitable for regions with a low prevalence of these enzymes.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Pseudomonas aeruginosa
/
Pseudomonas Infections
/
Beta-Lactamases
/
Disk Diffusion Antimicrobial Tests
Type of study:
Diagnostic_studies
/
Guideline
/
Risk_factors_studies
Limits:
Humans
Country/Region as subject:
Europa
Language:
En
Journal:
Scand J Infect Dis
Year:
2011
Document type:
Article
Affiliation country:
Netherlands