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Otopathogenic Pseudomonas aeruginosa Strains as Competent Biofilm Formers
Eric W. Wang, MD;
Jae Y. Jung, PhD;
Mary E. Pashia, MS;
Robert Nason, MD;
Steven Scholnick, PhD;
Richard A. Chole, MD, PhD
Arch Otolaryngol Head Neck Surg. 2005;131:983-989.
Objective To determine whether Pseudomonas aeruginosa, a common cholesteatoma pathogen, known to form biofilms in other chronic infections, is capable of contributing to biofilm formation in cholesteatoma.
Design We tested 12 OPPA isolates for several aspects of biofilm formation, including adherence to human keratinocytes, expression of quorum-sensing genes, twitching motility, and production of extracellular matrix as determined by both crystal violet staining and carbazole reaction.
Results Ten OPPA strains demonstrated increased adherence (1.5- to 12-fold) to human keratinocytes relative to PAO1, a laboratory strain. Expression of las and rhl quorum-sensing products were detected in 11 OPPA strains. By crystal violet staining, we found biofilm formation in all OPPA strains equal to or greater than that found in PAO1 (2- to 18-fold). In addition, OPPA strains demonstrated mucoid characteristics, including down-regulation of twitching motility and increased alginate production.
Conclusions Strains of OPPA isolated from cholesteatoma are strongly adherent to keratinocytes and capable of forming biofilm. In addition, OPPA strains have mucoid characteristics in vitro. When these bacteria assume a biofilm phenotype, they are highly resistant to antibiotics and host defenses. These data suggest that OPPA can contribute to biofilm formation in cholesteatoma, leading to the persistence of this infection.
Author Affiliations: Departments of Otolaryngology–Head and Neck Surgery (Drs Wang, Jung, Nason, Scholnick, and Chole and Ms Pashia), Genetics (Dr Scholnick) and Molecular Biology and Pharmacology (Dr Chole), and the Central Institute for the Deaf at Washington University (Dr Chole), Washington University School of Medicine, St Louis, Mo.
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