Epidemiology of infections caused by extended-spectrum b-lactamases producing Escherichia coli for a three-year period

Abstract number: 1733_59

Gallardo M.M., García M.V., Rodríguez R., Ropero F., Granados E., Gutierrez A., Pinedo A.

Objectives: For the last years we are being witness of an increase of ESBLs productive strain isolations, making more difficult managing carrier patients. Our aim is to get to know the clinical and epidemiologic features of the ESBLs producing E. coli in the population attending our hospital.

Methods: A retrospective study was carried out from January 2003 to December 2005, where a total of 8623 E. coli strains were isolated. Antimicrobial suceptibilities were carried out by the MicroScan Walkaway® automised system and by disk difussion test and E-test. Double-disk synergy test and E-test were used for screening ESBLs. The results interpretation were according NCCLS guidelines.

Results: Out of the total number of isolations obtained, the percentage of ESBLs strains was 4.5% (391) of which 59 (15.1%) were isolated during the year 2003, 81 (20.7%) during 2004 and 351 (64.2%) during 2005. In 71.1% of the cases the origin was extrahospitalarian. Urine was the sample where it was isolated more frequently in 67.5% of the cases followed by exudates (18.2%)and blood (8.4%). The 391 ESBL E. coli strains belonged to 391 patients 247 (63.1%) women and 144 (36.9%) men with an average age of 61.8 years old (range: 1–98). Hospitalised cases were 28.9% (113) and most of them in the internal medicine department (45.5%), followed by the surgical department (30%) and Intensive Care Units (24.5%). Progress of the hospitalised patients went to resolution in 71.4% of the cases being exitus in 28.5% of them.

In reference to sensitivity, co-resistance was detected with quinolones, fosfomycin, trimethoprim-sulfamethoxazole (TSX) and aminoglycosides, observing that the co-resistance more frequently found was with quinolones 71.1% followed by TSX 53.2%, aminoglycosides 20.7% and fosfomycin 4.9%. Only 76 (19.4%) did not show co-resistance with other groups of antibiotics. The co-resistance combination more frequently found was ESBLs more resistant to quinolones and TSX in 46% of the cases.

Conclusions: An important increase of ESBLs isolations have been proven from the year 2003–2004 to the year 2005. Most of the strains were of extrahospitalarian origin. A high level of co-resistance has been detected among ESBLs strains, where quinolones are the antibiotic family mostly affected.

Session Details

Date: 31/03/2007
Time: 00:00-00:00
Session name: European Society of Clinical Microbiology and Infectious Diseases
Location: ICC, Munich, Germany
Presentation type:
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