In vitro efficacy of phytotherapeutics suggested for prevention and therapy of urinary tract infections.

PURPOSE: To analyse the therapeutic efficacy of various phytotherapeutics and their antimicrobial compounds with regard to strain specificity and dose dependence. METHODS: A representative strain collection of 40 uropathogenic bacteria isolated from complicated and uncomplicated urinary tract infection was subjected to various virulence assays (bacterial growth, mannose-sensitive agglutination, and motility) to determine the therapeutic impact of various compounds with antimicrobial activity. We tested proanthocyanidins (PAC), D-mannose, rosemary extract (Canephron®), and isothiocyanates (Angocin®). RESULTS: D-mannose efficiently blocked the adhesive properties of all type 1 fimbriae-positive isolates in low concentration (0.2%), but showed no bacteriostatic effect. PAC also actively blocked agglutination, but the concentration varied considerably among isolates. Escherichia coli required the highest concentration (10%), while Enterobacter cloacae responded to low concentrations (0.1%). Allyl isothiocyanates not only impaired agglutination in all tested isolates, but also had a dramatic impact on flagella-mediated motility in Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis (p < 0.001). The administration of rosemary extracts revealed a strong bacteriostatic effect in growth assays. All tested strains were strongly inhibited by the addition of 10 µg/ml or 1 µg/ml of purified rosemary extractions with the exception of Serratia marcescens. Morganella morganii responded only to 10 µg/ml. CONCLUSION: Phytotherapeutics and small-molecular compounds like mannosides have the potential to become an integral part in a multi-modal treatment concept for the treatment and prevention of urinary tract infections. Their efficiency can be optimised when strain specificities and therapeutic concentrations are taken into account.

The high-pathogenicity island (HPI) promotes flagellum-mediated motility in extraintestinal pathogenic Escherichia coli.

The key of success of extraintestinal pathogenic Escherichia coli (ExPEC) to colonize niches outside the intestinal tract and to establish infection is the coordinated action of numerous virulence and fitness factors. The so-called high-pathogenicity island (HPI), responsible for synthesis, secretion and uptake of the siderophore yersiniabactin, proved to be an important virulence determinant. In this study we investigated the interaction of the flagellum-mediated motility and the HPI. The impairment of yersiniabactin production by deletion of irp2 or ybtA affected significantly motility. The gain of yersiniabactin production improved motility in both pathogenic and non-pathogenic E. coli strains. The loss of flagella expression had no adverse effect on the HPI. Strikingly, external iron abundance was not able to suppress activation of the HPI during motility. The HPI activity of swarming bacteria was comparable to iron deplete conditions, and could even be maximized by supplementing excessive iron. This fact is the first description of a regulatory mechanism, which does not follow the known hierarchical regulation of siderophore systems. Transcriptional reporter fusions of the ybtA promoter demonstrated that the entire promoter region with all YbtA binding sites is necessary for complete induction in both HPI-positive and HPI-negative strains. Altogether, these results suggest that the HPI is part of a complex regulatory network, which orchestrates various virulence mechanisms to optimize the overall fitness of ExPEC.

Comparison of ozone gas and sodium hypochlorite/chlorhexidine two-visit disinfection protocols in treating apical periodontitis: a randomized controlled clinical trial.

OBJECTIVES: In this single-blinded, prospective, randomized, controlled clinical trial, the effectiveness of an ozone gas or NaOCl/CHX disinfection protocol was compared within the root canal treatment of apical periodontitis. MATERIALS AND METHODS: Sixty permanent teeth were randomly allocated to one technique. The clinical/radiographic assessment criteria included clinical symptoms, periapical index (PAI), and size of the apical lesion. In both groups, the root canal was mechanically cleaned and irrigated with NaCl and EDTA. Ozone gas (32 g m-3) or NaOCl (3 %) was applied followed by a 1-week inter-appointment dressing (Ca(OH)2). As final disinfection, ozone gas (ozone group) or CHX 2 % (NaOCl group) was applied. Microbial samples were taken after preparing the access cavity, after chemo-mechanical treatment and after inter-appointment dressing by sterile paper points. Microbial identification was performed by mass spectroscopy (MALDI-TOF-MS) and 16S-rRNA gene sequencing. The treated teeth were blindly re-evaluated after 6/12 months. Success rates, the decrease in PAI, the size of apical lesions and bacterial reduction were compared between groups (Fischer's exact test, Mann-Whitney U test). RESULTS: There were no significant differences between the success rates (ozone group: 96.2/95.5 % after 6/12 months; NaOCl group: 95.5/95.2 % after 6/12 months). The differences in the decreases in PAI values and apical lesion sizes were also insignificant after 6 and 12 months. The bacterial reduction showed no significant differences between groups after chemo-mechanical treatment and after inter-appointment dressing. The most commonly found bacterial genera were Streptococcus spp., Parvimonas spp. and Prevotella spp. CONCLUSIONS: The here used ozone gas and NaOCl/CHX protocols showed no difference in bacterial reduction in the sampled areas of the root canals. CLINICAL RELEVANCE: Within the limitations of the study, ozone gas seems to be a possible alternative disinfection agent within the root canal treatment of apical periodontitis.