Biocide activity against urinary catheter pathogens.

Antimicrobial effects of essential oils against bacteria associated with urinary catheter infection was assessed. Tests were performed on 14 different bacterial species cultured either planktonically or as biofilms. Biofilms were found to be up to 8-fold more tolerant of the test agents. Higher antimicrobial tolerance was also evident in tests conducted in artificial urine. Eugenol exhibited higher antimicrobial effects against both planktonic cells and biofilms than did terpinen, tea tree oil, and cineole.

Development of an "early warning" sensor for encrustation of urinary catheters following Proteus infection.

Biofilm formation in long-term urinary catheterized patients can lead to encrustation and blockage of urinary catheters with serious clinical complication. Catheter encrustation stems from infection with urease-producing bacteria, particularly Proteus mirabilis. Urease generates ammonia from urea, and the elevated pH of the urine results in crystallization of calcium and magnesium phosphates, which block the flow of urine. The aim of this research is to develop an "early warning" silicone sensor for catheter encrustation following bacterial infection of an in vitro bladder model system. The in vitro bladder model was infected with a range of urease positive and negative bacterial strains. Developed sensors enabled catheter blockage to be predicted ~17-24 h in advance of its occurrence. Signaling only occurred following infection with urease positive bacteria and only when catheter blockage followed. In summary, sensors were developed that could predict urinary catheter blockage in in vitro infection models. Translation of these sensors to a clinical environment will allow the timely and appropriate management of catheter blockage in long-term catheterized patients.

Titanium surface modification and its effect on the adherence of Porphyromonas gingivalis: an in vitro study.

AIM: Titanium dental implants are an important treatment option in the replacement of missing teeth. Implant failures can, however, occur and may be promoted by the loss of tissue as a result of local bacterial infection (peri-implantitis). OBJECTIVES: Bacterial adherence to implant surfaces is believed to be influenced by material surface roughness and surface-free energy parameters. Consequently, the aim of this study was to modify these properties of titanium and identify what effect these modifications had on subsequent bacterial adherence. MATERIALS AND METHODS: In this study, 16 titanium samples of different roughness (R(a) 34.57-449.42 nm) were prepared using specific polishing procedures. A further six samples were chemically altered by argon plasma discharge treatment and immersion in silane solutions to produce different surface hydrophobicities. An in vitro adhesion assay using Porphyromonas gingivalis was used to assess the effect of modification on bacterial adherence. RESULTS: A significant reduction in adhesion to materials categorised as being 'very smooth' (R(a) 34.57+/-5.79 nm) was evident. This reduction did not occur with 'smooth' (R(a) 155.00+/-33.36 nm), 'rough' (R(a) 223.24+/-9.86 nm) or 'very rough' (R(a) 449.42+/-32.97 nm) surfaces. Changing material surface hydrophobicity was also not found to effect bacterial adhesion. CONCLUSIONS: Adhesion of P. gingivalis to titanium was inhibited at surface roughness levels below those generally encountered for implant collars/abutments (R(a) 350 nm). Considerations of these findings may be beneficial in the production of titanium implants in order to reduce bacterial colonisation.