Hypothesis: An albumin coating on titanium implants will inhibit bacterial adhesion on the implant surface. Background: Bacterial, protein, and platelet adhesion on otologic implants and tympanostomy tubes is a major reason for implant sequelae and can eventually lead to implant removal. The role of albumin coating of the implant in prevention of protein adhesion on implant surface has already been tested by the authors. In the present study the authors examined the in vitro adherence of Staphylococcus aureus and Pseudomonas aeruginosa on an albumin-coated and uncoated titanium surface. Methods: Human serum albumin (HSA)-coated and uncoated titanium surfaces were exposed to viable S. aureus and P. aeruginosa and, after washings, photographed by fluorescence microscopy to quantify the adhered bacteria, which was stained with acridine orange. Results: Bacteria in the suspension adhered at a significantly lesser rate to the coated surfaces than to the uncoated surfaces, with overall bacterial adhesion dependent on bacterial concentration. Binding of S. aureus on HSA-coated surfaces was inhibited significantly (from 82 to 95% depending on concentration). Binding of P. aeruginosa was inhibited from 29 to 37%. Conclusion: Because albumin coating can reduce bacterial adherence on titanium surfaces in vitro, reduction is possible in bacterial contamination and infection of the HSA-coated titanium implant in vivo.

Hydroxyapatite (HA) and biphasic calcium phosphate (BCP) ceramic materials are widely employed as bone substitutes due to their porous and osteoconductive structure. Their porosity and the lowering of surrounding pH as a result of surgical trauma may, however, predispose these materials to bacterial infections. For this reason, the influence of porosity and pH on the adherence of common Gram-positive bacteria to the surfaces of these materials requires investigation. Mercury intrusion porosimetry measurements revealed that the pore size distribution of both bioceramics had, on a logarithmic scale, a sinusoidal frequency distribution ranging from 50 to 300 nm, with a mean pore diameter of 200 nm. Moreover, total porosity was 20 % for HA and 50 % for BCP. Adherence of Staphylococcus aureus and Staphylococcus epidermidis was studied at a physiological pH of 7.4 and at a pH simulating bone infection of 6.8. Moreover, the effect of pH on the ζ potential of HA, BCP and of both staphylococci was evaluated. Results showed that when pH decreased from 7.4 to 6.8, the adherence of both staphylococci to HA and BCP surfaces decreased significantly, although at the same time the negative ζ-potential values of the ceramic surfaces and both bacteria diminished. At both pH values, the number of S. aureus adhered to the HA surface appeared to be lower than that for BCP. A decrease in pH to 6.8 reduced the adherence of both bacterial species (mean 57 %). This study provides evidence that HA and BCP ceramics do not have pores sufficiently large to allow the internalization of staphylococci. Their anti-adherent properties seemed to improve when pH value decreased, suggesting that HA and BCP bioceramics are not compromised upon orthopaedic use.

A study to evaluate the biofilm-development ability in three different media (Middlebrook 7H9, sterile tap water and PBS-5% glucose) was performed with 19 collection strains from 15 different species on non-pigmented rapidly growing mycobacteria (NPRGM). A microtiter plate assay was developed to evaluate the percentage of covered surface of the microtiter plate wells in different days from day 1 to day 69.

Hypothesis We designed a study to determine the role of mastoid mucosal biofilm in chronic otitis media (COM). Background Biofilm formation has been found in several chronic airway infections. COM is associated with chronic, recalcitrant infection of the mastoid mucosa, and surgery often is required. Methods COM patients were divided into 2 groups: one with chronic suppurative otitis media (CSOM) and one with cholesteatoma presence. All COM patients had mastoid involvement in a preoperative computed tomographic scan. The control group consisted of patients undergoing cochlear implantation, with no previous history of chronic otitis media. Mastoid mucosa samples were harvested during mastoidectomy. The samples were studied with multiplex-polymerase chain reaction and with CSLM using BacLight Live/Dead stain. Routine bacterial culture was performed in selected cases. Results A total of 29 COM patients underwent mastoidectomy. Mastoid mucosal biofilm formation could be found in 19 (66%) of these patients. In the control group, there were 11 cases of cochlear implantation, and 1 patient (9%) presented mastoid mucosal biofilm. In the cholesteatoma group, there were 17 patients, of which, 14 (82%) presented biofilm, whereas in the CSOM group, 5 (42%) of 12 patients presented biofilm. The correlation between COM and biofilm was statistically significant (Fisher’s exact test, p = 0.003), as was the correlation between cholesteatoma and biofilm, in comparison with the CSOM group (Fisher’s exact test, p = 0.046). Conclusion Mastoid mucosal biofilm could be seen in patients with COM with or without cholesteatoma. The role of mastoid biofilm in the development of cholesteatoma should be studied further.