Antibiotic Susceptibilities of Pseudomonas aeruginosa Isolates Derived from Patients with Cystic Fibrosis under Aerobic, Anaerobic, and Biofilm Conditions
Open Access
- 1 October 2005
- journal article
- research article
- Published by American Society for Microbiology in Journal of Clinical Microbiology
- Vol. 43 (10), 5085-5090
- https://doi.org/10.1128/jcm.43.10.5085-5090.2005
Abstract
Recent studies have determined that Pseudomonas aeruginosa can live in a biofilm mode within hypoxic mucus in the airways of patients with cystic fibrosis (CF). P. aeruginosa grown under anaerobic and biofilm conditions may better approximate in vivo growth conditions in the CF airways, and combination antibiotic susceptibility testing of anaerobically and biofilm-grown isolates may be more relevant than traditional susceptibility testing under planktonic aerobic conditions. We tested 16 multidrug-resistant isolates of P. aeruginosa derived from CF patients using multiple combination bactericidal testing to compare the efficacies of double and triple antibiotic combinations against the isolates grown under traditional aerobic planktonic conditions, in planktonic anaerobic conditions, and in biofilm mode. Both anaerobically grown and biofilm-grown bacteria were significantly less susceptible ( P < 0.01) to single and combination antibiotics than corresponding aerobic planktonically grown isolates. Furthermore, the antibiotic combinations that were bactericidal under anaerobic conditions were often different from those that were bactericidal against the same organisms grown as biofilms. The most effective combinations under all conditions were colistin (tested at concentrations suitable for nebulization) either alone or in combination with tobramycin (10 μg ml −1 ), followed by meropenem combined with tobramycin or ciprofloxacin. The findings of this study illustrate that antibiotic sensitivities are dependent on culture conditions and highlight the complexities of choosing appropriate combination therapy for multidrug-resistant P. aeruginosa in the CF lung.Keywords
This publication has 32 references indexed in Scilit:
- Azithromycin for cystic fibrosisEuropean Respiratory Journal, 2004
- Oxygen Limitation Contributes to Antibiotic Tolerance of Pseudomonas aeruginosa in BiofilmsAntimicrobial Agents and Chemotherapy, 2004
- Burkholderia pseudomallei: another emerging pathogen in cystic fibrosisThorax, 2003
- Pseudomonas aeruginosa Anaerobic Respiration in Biofilms: Relationships to Cystic Fibrosis PathogenesisDevelopmental Cell, 2002
- Pseudomonas biofilm formation and antibiotic resistance are linked to phenotypic variationNature, 2002
- Synergistic Activities of Macrolide Antibiotics against Pseudomonas aeruginosa , Burkholderia cepacia , Stenotrophomonas maltophilia , and Alcaligenes xylosoxidans Isolated from Patients with Cystic FibrosisAntimicrobial Agents and Chemotherapy, 2002
- Effects of reduced mucus oxygen concentration in airway Pseudomonas infections of cystic fibrosis patientsJCI Insight, 2002
- Cystic fibrosis. 1. Pseudomonas aeruginosa infection in cystic fibrosis and its management.Thorax, 1990
- Antibiotic interaction and diffusion through alginate and exopolysaccharide of cystic fibrosis-derived Pseudomonas aeruginosaJournal of Antimicrobial Chemotherapy, 1988
- Tolerance of Pseudomonas aeruginosa to killing by ciprofloxatin, gentamicin and imipenem in vitro and in vivoJournal of Antimicrobial Chemotherapy, 1988