PT - JOURNAL ARTICLE AU - K.W. Tsang AU - P. Ng AU - P.L. Ho AU - S. Chan AU - G. Tipoe AU - R. Leung AU - J. Sun AU - J.C. Ho AU - M.S. Ip AU - W.K. Lam TI - Effects of erythromycin on <em>Pseudomonas aeruginosa</em> adherence to collagen and morphology <em>in vitro</em> AID - 10.1183/09031936.03.00050903 DP - 2003 Mar 01 TA - European Respiratory Journal PG - 401--406 VI - 21 IP - 3 4099 - http://erj.ersjournals.com/content/21/3/401.short 4100 - http://erj.ersjournals.com/content/21/3/401.full SO - Eur Respir J2003 Mar 01; 21 AB - The airways of patients with bronchiectasis and cystic fibrosis are often chronically colonised by Pseudomonas aeruginosa (PA), which is virtually impossible to eradicate. Low-dose erythromycin (EM), for unknown mechanisms, is efficacious in bronchiectasis and diffuse panbronchiolitis. In this study, an in vitro model to investigate PA adherence to human type IV basement collagen was developed by using scanning electron microscopy (SEM). There were significantly less PA bacilli per 20 random SEM fields (4,000×) when PA was cultured in 0.05, 0.5 and 5 µg·mL−1 of EM compared with control (absence of EM). Adherence density (20 SEM fields·log−1 inocular size) for PA obtained from no EM (56.8±43.16) was significantly higher than that obtained from 0.05, 0.5, and 5 µg·mL−1 EM (21.5±17.56, 23.3±16.65, and 21.4±12.65 respectively). By using SEM it was found that PA, when incubated in EM (0.05, 0.5, 5 µg·mL−1) had a significant reduction in its diagonal length, radius, height, volume and surface area. It is possible, therefore, that these misshaped Pseudomonas aeruginosa bacilli are more susceptible to host defence mechanisms, while at the same time less adherent to the basement membrane of the airway in vivo. Therefore, this could help explain the clinical efficacy of low-dose erythromycin therapy on patients with Pseudomonas aeruginosa infection. This study was funded by a Hong Kong RGC Grant.