First report of an acute purulent maxillary sinusitis caused by Pseudomonas aeruginosa secondary to dental implant placement in an immunocompetent patient

Developing an ecologically relevant heterogeneous biofilm model for dental-unit waterlines

This study monitored the biodiversity of microbes cultured from a heterogeneous biofilm which had formed on the lumen of a section of dental waterline tubing over a period of 910 days. By day 2 bacterial counts on the outlet-water showed that contamination of the system had occurred. After 14 days, a biofilm comparable to that of clinical waterlines, consisting of bacteria, fungi and amoebae had formed. This showed that the proprietary silver coating applied to the luminal surface of the commercial waterline tubing failed to prevent biofilm formation. Molecular barcoding of isolated culturable microorganisms showed some degree of the diversity of taxa in the biofilm, including the opportunistic pathogen Legionella pneumophila. Whilst the system used for isolation and identification of contaminating microorganisms may underestimate the diversity of organisms in the biofilm, their similarity to those found in the clinical environment makes this a promising test-bed for future biocide testing.

Evaluation of treatment outcomes and clinical indications for antibiotic prophylaxis in patients undergoing implantation procedures

PURPOSE

The use of antibiotic therapy during implantation to reduce the risk of an early implant failure is widely discussed among clinicists. However, half an hour after the procedure a quarter of patients show bacteremia which could decrease the efficacy of the surgery. Implant failure is associated with destruction of bone tissue within the alveolar process and may lead to an alternative but compromised treatment plan. The aim of the study was to evaluate the influence of perioperative antibiotic protection on success of implantation.

MATERIAL AND METHODS

The retrospective study involved 1915 patients (females: 57.3%, males: 42.7%) with no systemic or local diseases, who required antibiotic therapy during surgical procedures. Group 1 comprised 203 patients with diagnosed vertical or horizontal bone atrophy within the alveolar ridge requiring reconstruction procedure before implantation. Group 2 included 1712 patients who did not need any surgical procedures before implantation. All the subjects took three types of antibiotics twice a day for 7 days. The data were statistically analyzed.

RESULTS

A total number of 3309 implants were placed. Implantation efficacy in group 1 amounted to 98.53% and in group 2 it was 99.24%. Complications occurred most commonly after administration of cephalosporin which proved to be statistically significant for the patients who underwent augmentation with a bone block before the implant procedure (p 0.0209).

CONCLUSIONS

Perioperative use of antibiotic therapy beneficially influences tissue healing, provides safety and success of the surgical procedure, as well as translates into high efficacy of implantation (99.52%).

Bacterial influence on consolidation of bone grafts in maxillary sinus elevation

OBJECTIVES

The aim of this study was to identify microorganisms present on the maxillary sinus floor at the moment of sinus elevation surgery and, using tomography, to investigate the repercussions these might have for regenerated bone 9 months after the procedure.

MATERIALS AND METHODS

174 patients (90 women and 84 men) with a mean age of 55.92 years underwent 227 sinus elevations (120 left sinus, 107 right sinus). As the membrane was lifted, a sample of the maxillary sinus floor was collected with a cotton swab, and placed on a blood agar and chocolate agar culture to incubate for 48 h at 37°C; the samples then underwent microbiological analysis. Orthopantomographs and computerized tomographs were made immediately after the sinus grafting and after 9 months to measure the amount of remaining and regenerated bone in vertical and transversal direction.

RESULTS

18.1% of 227 cultures were bacteria-positive. 45% of the germs were of the Streptococcus genus, most of which belonged to the S. viridans group (61.1%). Patients presenting negative cultures had 5% more regenerated bone than patients with bacteria-positive cultures, which represents an additional 2.28 mmof vertical bone (with a confidence interval between 0.83 mm and 3.73 mm).

CONCLUSIONS

Patients with bacteria-positive cultures obtained previously to the sinus grafting procedure have greater risk of bone height loss after 9 months, which indicates that bacterial contamination may influence bone graft regeneration.

Virulence Attributes and Host Response Assays for Determining Pathogenic Potential of Pseudomonas Strains Used in Biotechnology

Pseudomonas species are opportunistically pathogenic to humans, yet closely related species are used in biotechnology applications. In order to screen for the pathogenic potential of strains considered for biotechnology applications, several Pseudomonas strains (P.aeruginosa (Pa), P.fluorescens (Pf), P.putida (Pp), P.stutzeri (Ps)) were compared using functional virulence and toxicity assays. Most Pa strains and Ps grew at temperatures between 28°C and 42°C. However, Pf and Pp strains were the most antibiotic resistant, with ciprofloxacin and colistin being the most effective of those tested. No strain was haemolytic on sheep blood agar. Almost all Pa, but not other test strains, produced a pyocyanin-like chromophore, and caused cytotoxicity towards cultured human HT29 cells. Murine endotracheal exposures indicated that the laboratory reference strain, PAO1, was most persistent in the lungs. Only Pa strains induced pro-inflammatory and inflammatory responses, as measured by elevated cytokines and pulmonary Gr-1 -positive cells. Serum amyloid A was elevated at ≥ 48 h post-exposure by only some Pa strains. No relationship was observed between strains and levels of peripheral leukocytes. The species designation or isolation source may not accurately reflect pathogenic potential, since the clinical strain Pa10752 was relatively nonvirulent, but the industrial strain Pa31480 showed comparable virulence to PAO1. Functional assays involving microbial growth, cytotoxicity and murine immunological responses may be most useful for identifying problematic Pseudomonas strains being considered for biotechnology applications.