In vitro susceptibility patterns to 13 antimicrobials against Pseudomonas aeruginosa cystic fibrosis patients in the UK

Abstract number: P2096

Khanna P., Soleimanian S., Wareham D.

Objectives: Respiratory tract colonisation and infection in cystic fibrosis (CF) patients contributes to the progressive decline in lung function. Pseudomonas aeruginosa, is the most common bacterial pathogen and is often exhibits multi-drug resistance. We conducted a surveillance of resistance to 13 commonly used agents amongst isolates from a large UK CF centre to provide an indicator of the prevalence of resistance in 2005–2007.

Methods: 478 strains of P. aeruginosa were isolated from CF sputum over a 24 month. Strains were identified by growth on Pseudomonas Isolation agar, API 20NE and confirmed by specific PCR. Isolates were classified as mucoid or non-mucoid and tested for susceptibility to amikacin, ceftazidime, ciprofloxacin, gentamicin, imipenem, meropenem, piperacillin/tazobactam, azlocillin, aztreonam, colistin, tobramycin, cefpirome and ticarcillin/clavulanate by the BSAC disc diffusion method.

Results: Only 21.2% of the isolates were sensitive to all antibiotics tested. The most active agent was colistin (1.1%) followed by tobramycin (13.4%) and piperacillin/tazobactam (17.8%).11 isolates were resistant to all antibiotics except for colistin. Resistance to cefpirome was (74%), ciprofloxacin (40.5%), gentamicin (39.3%), ticarcillin/clavulanate (38.5%), imipenem (38.5%), meropenem (33.3%), aztreonam (31.6%), azlocillin (28.7%), ceftazidime (26.2%) and amikacin (25.3%). In-vitro susceptibility of mucoid P. aeruginosa isolates was greater than non-mucoid isolates (p < 0.05 for gentamicin, tobramycin, amikacin, ticarcillin/clavulante, azlocillin, aztreonam and ciprofloxacin). Multi-drug resistance (geqslant R: gt-or-equal, slanted5 antibiotics) occurred in 55.3% of isolates.

Conclusion:P. aeruginosa CF isolates exhibit very high rates of antimicrobial resistance. This not only complicates treatment of chronic infection and exacerbations difficult but may be an important reservoir of antimicrobial resistance determinants for dissemination to non-CF strains. Continued surveillance of antibiograms and monitoring for new resistance genes in this population is warranted.

Session Details

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