Differences in biofilm development and antibiotic susceptibility among Streptococcus pneumoniae isolates from cystic fibrosis samples and blood cultures.
OBJECTIVE
To compare the capability of biofilm development between Streptococcus pneumoniae isolates from cystic fibrosis (CF) respiratory samples and those from non-CF blood cultures. Antibiotic susceptibility of biofilm-forming isolates, as well as differences between antibiotic susceptibility of sessile cells [minimum biofilm inhibitory concentration (MBIC)] and their planktonic counterparts (conventional MIC), were also assessed.


METHODS
Biofilm formation was performed using a microtitre method in 20 CF and 22 non-CF blood culture S. pneumoniae isolates.


CONCLUSIONS
Biofilm formation occurs more frequently among S. pneumoniae isolates from CF (80%) than among non-CF blood culture isolates (50%) (P = 0.04). Moreover MBICs were significantly higher than conventional planktonic MICs among CF but not among non-CF blood isolates, suggesting a high adaptability of CF strains to form biofilms in adverse conditions.
García-Castillo
María
M
Servicio de Microbiología, Hospital Universitario Ramón y Cajal Ctra. Colmenar Km 9.1, Madrid 28034, Spain.
Morosini
María Isabel
MI
Valverde
Aránzazu
A
Almaraz
Felisa
F
Baquero
Fernando
F
Cantón
Rafael
R
del Campo
Rosa
R
D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use; D018441:Biofilms / Q000187:drug effects / Q000254:growth & development; D001769:Blood / Q000382:microbiology*; D003550:Cystic Fibrosis / Q000382:microbiology*; D024881:Drug Resistance, Bacterial; D006801:Humans; D008826:Microbial Sensitivity Tests; D011008:Pneumococcal Infections / Q000097:blood / Q000382:microbiology; D013296:Streptococcus pneumoniae / Q000187:drug effects / Q000254:growth & development / Q000302:isolation & purification
D000900:Anti-Bacterial Agents