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In vitro activity of tigecycline tested against pneumonia pathogens from patients hospitalised in European medical centres, including multidrug-resistant Acinetobacter spp.

Abstract number: P680

Sader H., Jones R., Janechek M., Fritsche T.

Objectives: Emergence of resistance (R) among pneumonia-producing pathogens has been a variable that confounds empiric management. We evaluated the activity of tigecycline against leading bacterial pathogens recovered from patients hospitalised with pneumonia. Tigecycline was approved by the European Medicines Agency and US-FDA for the treatment of complicated skin and skin structure infections and intra-abdominal infections and is currently under investigation for treatment of hospital acquired pneumonia.

Methods: Consecutive, non-duplicate, lower respiratory tract isolates (3,864) were submitted from 34 medical centres located in Europe (13 countries) and Israel in the 2000–2007 period. Susceptibility (S) tests were performed using CLSI methods (including ESBL confirmatory tests) and interpreted by US-FDA and EUCAST criteria.

Results: Ranking of the top-10 occurring pneumonia pathogens and key resistance (R) characteristics were (see Table): S. aureus (28.3% oxacillin-R [MRSA]) > P. aeruginosa (19.6 imipenem [IMI]-R) > E. coli (8.5% ESBL) > Klebsiella spp. (28.9% ESBL) > Enterobacter spp. (25.6% ceftazidime [CAZ]-R) > Acinetobacter spp. > S. pneumoniae (23.1% penicillin-R) > Serratia spp. > S. maltophilia > H. influenzae (12.8%b-lactamase positive). Acinetobacter spp. exhibited high R rates to IMI (43.1%), CAZ (77.0%), ciprofloxacin (CIP; 82.8%) and amikacin (AMK; 65.1%); while 34.9% of strains were R to all 4 drugs (MDR). R to these antimicrobials did not adversely affect tigecycline activity, which inhibited >95% of strains non-S to CAZ, CIP or AMK, 93.3% of strains non-S to IMI and 91.8% of MDR strains at leqslant R: less-than-or-eq, slant2 mg/L. Tigecycline was also very active against S. maltophilia (MIC90, 2 mg/L; 99.2% inhibited at leqslant R: less-than-or-eq, slant2 mg/L), MRSA (MIC90, 0.25 mg/L; 99.5% S) and Enterobacteriaceae with an ESBL-phenotype, but showed limited activity against PSA.

Conclusions: Tigecycline is a potent agent targeting pneumonia pathogens displaying highly resistant phenotypes including S. aureus, Enterobacteriaceae, S. pneumoniae, H. influenzae, and some non-fermentative Gram-negative bacilli. Only tigecycline and the polymyxins showed reasonable in vitro activity against Acinetobacter spp. Empiric use of tigecycline may be prudent for patients less likely to have P. aeruginosa as a causative pathogen or for directed therapy of indicated species.

Session Details

Date: 19/04/2008
Time: 00:00-00:00
Session name: 18th European Congress of Clinical Microbiology and Infectious Diseases
Subject:
Location: Barcelona, Spain
Presentation type:
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