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Bacterial adhesion on titanium implant surfaces has a strong influence on healing and long-term outcome of dental implants. Parameters like surface roughness and chemical composition of the implant surface were found to have a significant impact on plaque formation. The purpose of this study was to evaluate the influence of two physical hard coatings on bacterial adhesion in comparison with control surfaces of equivalent roughness. Two members of the oral microflora, Streptococcus mutans and Streptococcus sanguis were used. Commercially pure titanium discs were modified using four different surface treatments: physical vapour deposition (PVD) with either titanium nitride (TiN) or zirconium nitride (ZrN), thermal oxidation and structuring with laser radiation. Polished titanium surfaces were used as controls. Surface topography was examined by SEM and estimation of surface roughness was done using a contact stylus profilometer. Contact angle measurements were carried out to calculate surface energy. Titanium discs were incubated in the respective bacterial cell suspension for one hour and single colonies formed by adhering bacteria were counted by fluorescence microscopy. Contact angle measurements showed no significant differences between the surface modifications. The surface roughness (Ra) of all surfaces examined was between 0.14 and 1.00 microm. A significant reduction of the number of adherent bacteria was observed on inherently stable titanium hard materials such as TiN and ZrN and thermically oxidated titanium surfaces compared to polished titanium. In conclusion, physical modification of titanium implant surfaces such as coating with TiN or ZrN may reduce bacterial adherence and hence improve clinical results.

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This study was aimed at determining the ability of different coronal temporary fillings to prevent corono-apical penetration of bacteria. A total of 103 human teeth, including three controls, were instrumented, obturated with gutta-percha, coronally sealed with either Cavit, Intermediate Restorative Material (IRM), glass-ionomer cement, Cavit/glass-ionomer cement, or IRM/glass-ionomer cement, respectively. Each root was fixed with wax between two chambers: the coronal chamber harboring soy broth with 10(8) colony-forming units of Streptococcus mutans/ml, the apical chamber containing sterile soy broth. The latter was checked daily for turbidity, indicating corono-apical penetration of bacteria. The Cavit group, the IRM group, and the Cavit/glass-ionomer cement group showed significantly more leakage than the glass-ionomer cement group of the IRM/glass-ionomer cement group. If a sample leaked, all except one (IRM/glass-ionomer cement) leaked before day 12. This in vitro study seems to indicate that only glass-ionomer cement and IRM combined with glass-ionomer cement may prevent bacterial penetration to the periapex of root-filled teeth over a 1-month period.

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Most mucocutaneous surfaces of humans harbor a rich indigenous microbial flora with predominance of anaerobes. Anaerobic infections are usually endogenous indicating that they originate from the host's own flora. Important exceptions are botulism, tetanus, food poisoning by Clostridium perfringens, some cases of gas gangrene and cases of hospital-acquired C. difficile-induced diarrhea. Endogenous anaerobic infections often occur in adjacent to the mucosal surfaces. Other organs are infected by penetration or hematogenous spread. A predisposing condition to anaerobic infections is a low redox potential resulting from tissue destruction, foreign bodies, malignancy or vascular insufficiency. A mixed anaerobic-aerobic infection is often found in abscesses or tissue necrosis. Antimicrobial therapy must take into account that anaerobic infections are often associated with aerobic bacteria.

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The national strategy for the use of chemotherapeutics under which there is a distinction between therapeutics and growth promoters for all uses (human medicine, veterinary medicine, animal nutrition) has resulted in a distinct reduction of the selection pressure and a decrease of the OTC resistance among Enterobacteriaceae in the eastern German Länder (formerly GDR) due to a reduction of OTC feeding after 1981 and the final prohibition in 1983. In the following years Enterobacteriaceae were investigated as infectious pathogens for humans and animals using antibiograms. On the one hand, the OTC resistance of porcine and bovine E. coli strains decreased only by 27% and 17%, respectively, during the 1980 to 1988 period, on the other, the OTC resistance of bovine S. typhimurium dropped by 65%, porcine S. typhimurium by 50%, bovine S. dublin by 50%, porcine S. choleraesuis by 30% to a resistance level of about 13% (1989) demonstrating a reduced pressure of resistance. At the same time, OTC resistance became diminished from 50% and 70%, respectively, to 30% also in Enterobacteriaceae (E. coli, Klebsiella) and enterococci isolated from urine and wound infections of patients in the non-agricultural population although therapeutic habits had remained unchanged. The results shown point to a spreading of resistance plasmids which has to be expected far beyond the field of OTC use, for example after the use of antibacterial growth promoters in livestock farming. Control measures should be introduced.

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40 uninephrectomized male Wistar rats with an experimental E.-coli-022-pyelonephritis (PN) were treated twice daily for 9 days with 30 mg trimethoprim and 150 mg sulfamethoxazole (TMP-SMO) i.p. Bacteriologically most of the kidneys became sterile. Histologically a significant reduction of the frequency of severe PN was found in the treated group. The biologic half-life of 131I-hippuran indicated a decrease of excretory function which was reversible. Urine osmolality and osmotic clearance were increased after oral water loading in 10 untreated control animals with PN but not in the treated group. The 9 day treatment had a favourable effect bacteriologically, histologically and also on renal function.

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Short-term antibiotic treatment is recommended in infections of the lower urinary tract but its effectiveness is questioned in the upper urinary tract infections. We compared a 5 and a 9 day treatment of experimental E. coli 022 pyelonephritis after unilateral nephrectomy in 127 mal Wistar rats. We used 9 mg gentamycin per kg b.w. twice daily. I131 hippurat excretion was not decreased during the 5 day treatment but was only temporarily diminished during the 9 day treatment. Histologically the severe acute pyelonephritis was decreased after the 9 day treatment but not after 5 days of treatment. Bacteriologically almost all the kidneys were sterile after the 9 day treatment but the majority of the kidneys showed the injected strain of E. coli after the 5 day treatment. The results indicated that the shortened treatment was much less effective in our acute experimental pyelonephritis.

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