Discrete nanoparticles induce loss of Legionella pneumophila biofilms from surfaces.

Nanoparticles (NPs) have been shown to induce dispersal events in microbial biofilms but the mechanism of the dispersal is unknown. Biofilms contaminate many man-made aquatic systems such as cooling towers, spas and dental lines. Within these biofilms, Legionella pneumophila is a primary pathogen, leading to these environments serving as sources for disease outbreaks. Here we show a reduction in biofilm bio-volume upon treatment with citrate-coated 6-nm platinum NPs, polyethylene glycol (PEG)-coated 11-nm gold NPs, and PEG-coated 8-nm iron oxide NPs. Treatment with citrate-coated 8-nm silver NPs, however, did not reduce biomass. The synthesis of NPs that remain dispersed and resist irreversible aggregation in the exposure media appears to be a key factor in the ability of NPs to induce biofilm dispersal.

Group B streptococcus: prevalence in a non-obstetric population.

OBJECTIVE: To establish and compare the prevalence of group B streptococcus (GBS) colonization in the vaginas of nonobstetric women with and without vaginitis. MATERIALS AND METHODS: Cross-sectional analysis GBS vaginal culture status of nonpregnant, estrogen-replete women 18 years or older presenting for annual gynecological examinations or vaginal infection. Subjects were classified into 3 groups: no vaginitis if symptoms were absent and examination results was normal; common vaginitis (CV) if microscopic examination revealed yeast, bacterial vaginosis, or trichomonads; or inflammatory vaginitis (IV) if examination revealed inflammation and immature squamous cells but no pathogens. RESULTS: Of the 215 women recruited, 147 (68.4%) showed no evidence of vaginitis, 41 (19.1%) had CV, and 27 (12.6%) showed evidence of IV. The overall prevalence rate of GBS was 22.8%. Vaginitis was associated with a significantly increased risk of GBS colonization (adjusted odds ratio: CV = 2.7, 95% CI = 1.1-6.2; IV = 2.9, 95% CI = 1.1-8.0). Logistic regression revealed pH higher than 4.5, presence of abnormal discharge on examination, and a women's complaint of current symptoms as significant predicators of the presence of GBS. CONCLUSIONS: Group B streptococcus colonization occurs more commonly in women with vaginitis. This suggests that disruption of the normal vaginal bacterial environment is an important predictor for GBS colonization.