Prevalence of extended-spectrum beta-lactamases in Enterobacteriaceae, Pseudomonas and Stenotrophomonas as determined by the VITEK 2 and E test systems in a Kuwait teaching hospital.
OBJECTIVE
To determine the prevalence of extended-spectrum beta-lactamase (ESBL)-producing members of the Enterobacteriaceae using VITEK 2 and E test systems.


METHODS
A total of 3,592 consecutive gram-negative isolates (single isolate per patient) of the family of Enterobacteriaceae and Pseudomonas adjudged to be clinically relevant to the patient's infection were studied for ESBL production over a period of 1 year at Mubarak Al-Kabeer Hospital, Kuwait. Two methods were used: the automated VITEK 2 system and E test ESBL, a manually manipulated plastic strip containing various gradients of beta-lactam antibiotics. These tests and interpretative criteria for the results were performed according to the manufacturer's instructions.


RESULTS
Of the 3,592 bacterial isolates, 264 (7.5%) and 185 (5.2%) were positive for ESBL production by the VITEK 2 and E test, respectively. All the ESBL-producing Pseudomonas aeruginosa identified by VITEK 2 gave indeterminate results by E test. Prevalent ESBL producers, identified by the VITEK 2 versus E test, respectively, were: Citrobacter spp. (15 vs. 3.2%), K. pneumoniae (12.2 vs. 11.4%), Enterobacter spp. (12 vs. 3%), E. coli (6.5 vs. 5.6%), P. aeruginosa (6.5 vs. 0%) and Morganella spp. (2 vs. 1%). The most common infection associated with ESBL-producing pathogens was urinary tract infection (68.2%), followed by wound infection (14.4%) and bloodstream infection (6.1%).


CONCLUSIONS
The result of this study showed a relatively high prevalence of clinically significant ESBL producers among the Enterobacteriaceae and Pseudomonas spp. at our teaching hospital. The VITEK 2 identified a higher prevalence of ESBL strains than the E test.
Jamal
Wafaa
W
Division of Microbiology, Mubarak Al-Kabeer Hospital, Kuwait.
Rotimi
V O
VO
Khodakhast
Fatima
F
Saleem
Rolla
R
Pazhoor
Aleyamma
A
Al Hashim
Ghyada
G
D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001322:Autoanalysis; D001431:Bacteriological Techniques / Q000379:methods*; D019818:Clavulanic Acid / Q000494:pharmacology; D003428:Cross Infection / Q000145:classification / Q000382:microbiology*; D024881:Drug Resistance, Bacterial; D004755:Enterobacteriaceae / Q000201:enzymology* / Q000302:isolation & purification; D004756:Enterobacteriaceae Infections / Q000188:drug therapy / Q000382:microbiology; D016905:Gram-Negative Bacterial Infections / Q000188:drug therapy / Q000382:microbiology*; D006784:Hospitals, Teaching; D006801:Humans; D007730:Kuwait; D015995:Prevalence; D011549:Pseudomonas / Q000201:enzymology* / Q000302:isolation & purification; D011552:Pseudomonas Infections / Q000188:drug therapy / Q000382:microbiology; D020588:Stenotrophomonas / Q000201:enzymology* / Q000302:isolation & purification; D001618:beta-Lactamases / Q000096:biosynthesis*
D000900:Anti-Bacterial Agents; D019818:Clavulanic Acid; D001618:beta-Lactamases