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Impact of extended-spectrum beta-lactamases produced by Gram-negative bacteria on efficacy of cephalosporins and quinolones

Abstract number: 1134_01_30

Yakovlev S., Romashov O., Sidorenko S.V., Eryomina L.

Objective:  

Assessment of efficacy of 3rd and 4th generation cephalosporins and quinolones in nosocomial pneumonia caused by gram-negative bacteria resistant to multiple antibiotics depending on their capacity to produce extended-spectrum beta-lactamases (ESBL).

Methods:  

We studied the cases of nosocomial pneumonia caused by gram-negative micro-organisms at an emergency hospital. The patients included in the study were on 3rd or 4th generation cephalosporins or quinolones therapy as a initial empiric therapy for nosocomial pneumonia. The strains which supposedly produced ESBL were tested for ESBL production in compliance of NCCLS criteria. To identify the type of ESBL, PCR and sequencing techniques were used.

Results:  

During the period of 2001–2003, sixty-two cases of nosocomial pneumonia were diag-nosed, resulting from infection with Enterobacteriaceae strains or non-fermenting microorganisms suspicious of producing ESBL. As the initial monotherapy, 25 patients were taking cefepime, 13 individuals – 3rd generation cephalosporins, while 20 patients were on quinolones. The etiologic factors of pneumonia were Klebsiella spp. (22 strains), E.coli (14), P. aeruginosa (15), Acinetobacter spp. (11). The ESBL-producing capacity has been confirmed in twenty-five Enterobacteriaceae strains by eighteen Klebsiella spp. strains and seven E. coli strains that produced ESBL. In contrast, none of non-fermenting microorganisms demonstrated the capacity to produce ESBL. The testing of strains that produced ESBL helped find the prevalence of ESBL types as follows (totally 30 types): TEM-3, SHV-15, CTX-UNI-6, CTX-A-3, CTX-C-3. The clinical efficacy of the antibiotics under investigation against the microorganisms, both with and without the ESBL-producing capacity, is shown in the Figure. The eradication rate of ESBL-producers was twice as higher in patients who were on cefepime as compared with those in patients taking 3rd generation cephalosporins or quinolones, 88.4 and 43.0%, respectively.

Conclusions:  

The efficacy of cefepime in nosocomial pneumonia is high and does not depend on the microorganism's ESBL-producing capacity. The effectiveness of 3rd generation cephalosporins proved satisfactory in case of lack of the bacterial ESBL-producing capacity, but it tended to be 1.5-fold lower if it was due to a ESBL-producer. The same was true in individuals on quinolones. Thus, the empiric therapy of nosocomial pneumonia was the most effective with cefepime.

Session Details

Date: 01/08/2007
Time: 00:00-00:00
Session name: XXIst ISTH Congress
Subject:
Location: Oxford, UK
Presentation type:
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