Caries and gingivitis are the most prevalent oral infectious diseases of humans and are due to the accumulation of dental plaque (a microbial biofilm) on the tooth surface and at the gingival margin, respectively. Several in vitro and in vivo studies have shown that many natural components of foods and beverages inhibit the adhesion of and/or exert activity against oral bacteria. These biological activities have mainly been attributed to the polyphenol fraction. In order to explore the possibility that diet can alter the dental plaque community, in this study we evaluated the composition of the microbiota of supra-and subgingival plaque samples collected from 75 adult subjects with different drinking habits (drinkers of coffee, red wine, or water for at least 2 years) by analyzing the microbial population through the separation of PCR-amplified fragments using the denaturing gradient gel electrophoresis (DGGE) technique. The mean numbers of bands of the DGGE profiles from all three categories were evaluated. There were no significant differences between the two kinds of plaque collected from the control group (water drinkers), and this group showed the highest number of bands (supragingival plaque, 18.98 ؎ 3.16 bands; subgingival plaque, 18.7 ؎ 3.23 bands). The coffee and wine drinker groups generated the lowest numbers of bands for both supragingival plaque (coffee drinkers, 8.25 ؎ 3.53 bands; wine drinkers, 7.93 ؎ 2.55 bands) and subgingival plaque (coffee drinkers, 8.3 ؎ 3.03 bands; wine drinkers, 7.65 ؎ 1.68 bands). The differences between coffee drinkers or wine drinkers and the control group (water drinkers) were statistically significant. A total of 34 microorganisms were identified, and the frequency of their distribution in the three subject categories was analyzed. A greater percentage of subjects were positive for facultative aerobes when supragingival plaque was analyzed, while anaerobes were more frequent in subgingival plaque samples. It is noteworthy that the frequency of identification of anaerobes was significantly reduced when the frequencies for coffee and wine drinkers were compared with the frequencies for subjects in the control group. The DGGE profiles of the organisms in both plaque samples from all groups were generated and were used to construct dendrograms. A number of distinct clusters of organisms from water, coffee, and wine drinkers were formed. The clustering of some of the DGGE results into cohort-specific clusters implies similarities in the microbiotas within these groups and relevant differences in the microbiotas between cohorts. This supports the notion that the drinking habits of the subjects may influence the microbiota at both the supragingival and the subgingival levels.

The presence of enterococci in lake and seawater in an 18-month survey comparing molecular (PCR and quantitative PCR) and culture methods was evaluated, as well as the possibility that zooplankton could act as reservoirs for enterococci. Samples of both water and zooplankton were collected monthly from a Lake Garda site and an Adriatic Sea site. In lake water, the positive samples numbered 13 of 54 (24%) by culture and 32 of 54 (59%) when PCR was applied. In seawater, they numbered 0 of 51 by culture and 18 of 51 (35%) by PCR. Enterococci were found either totally bound to plankton or totally in water, depending on the presence or absence of plankton, respectively. These results clearly indicate that the PCR assay is a powerful tool for detecting fecal indicators and pathogens in the environment, thus providing a much more sensitive method than culture.

In patients presenting mucositis, effective sub-gingival debridement is crucial to prevent peri-implantitis. The aim of this randomized study was to assess the three-month (T1) effects of a locally delivered liquid desiccant agent with molecular hygroscopic properties, in association with manual debridement, at sites with peri-implant mucositis. Twenty-three patients presenting at least one implant with no radiographically detectable bone loss, a pocket probing depth (PPD) ≥ 4 mm, and bleeding on probing (BOP), were included. At baseline (T0), patients were randomly assigned to receive the aforementioned desiccant agent before debridement (Test-Group), or a Chlorhexidine 1% disinfectant gel after debridement (Control-Group). Treatments were repeated after seven and 14 days. Peri-implant soft tissue assessment [PPD, BOP, Modified Bleeding Index (mBI), Visible Plaque Index (VPI), and Modified Plaque Index (mPLI)] and microbial sampling were performed at T0 and T1. At T1 the Test-Group presented significantly greater reductions for BOP, mBI, VPI, and mPLI. Concerning the deepest sites of the treated implants, both groups showed statistically significant reductions for BOP and mBI between T0 and T1. Furthermore, the Test-Group exhibited a significant decrease in anaerobic bacteria. Despite these valid outcomes, a complete resolution of the inflammatory conditions was not achieved by any of the groups.

Several human pathogens and fecal-pollution indicators may persist as viable organisms in natural environments, owing to their ability to activate different types of survival strategies. These strategies include adhesion on both abiotic and biotic surfaces and the entrance to the so-called viable but nonculturable (VBNC) state. In an 18-month survey for the detection of enterococci in both lake water and seawater, C. Several human pathogens and fecal-pollution indicators may persist as viable organisms in natural environments because of their ability to activate different types of survival strategies. These strategies include adhesion, possibly the formation of biofilm on both abiotic and biotic surfaces (5, 13-15, 23, 34), and the entry into the so-called viable but nonculturable (VBNC) state. Bacteria in the VBNC state are characterized by loss of culturability on conventional growth media, but cells maintain viability, pathogenicity factors, and the potential ability to reinfect humans on resuscitation to the culturable state (2, 8-10, 17, 20, 21, 26).Among human pathogens, the role of the adhesion of Vibrio cholerae, the etiological agent of a severe waterborne diarrheal disease (cholera), as well as of other vibrios, was extensively investigated, and it has been suggested that altered forms of V. cholerae in specific association with plankton organisms are the most plausible reservoirs of fully virulent strains during interepidemic periods (9). Bacterial binding to various surfaces involves several forces, ranging from hydrophobic and ionic bonds to the lectin-like interactions between the bacterial ligand(s) and complementary receptor(s) displayed by the substrate. A few examples of specific interactions between humanpathogenic bacteria and chitin-containing surfaces are known, but they are entirely restricted to the Vibrio genera. Lectins with specificity for N-acetylglucosamine (GlcNAc), the sugar component of chitin, have been demonstrated to occur in V. cholerae, Vibrio harveyi, Vibrio damsela, and Vibrio furnissii (24,29,36). In addition, specific chitin-binding proteins (CBPs) are displayed on the surfaces of V. cholerae (29,35), Vibrio alginolyticus (5, 27), and V. harveyi (24) and have been shown to be directly correlated to the binding ability of the microorganisms to various substrates.In an 18-month survey for the detection of enterococci in both lake water and seawater, Signoretto et al. (32) have shown that Enterococcus faecalis was bound mostly to plankton when present. In addition, E. faecalis, either in bound or in free form, was most frequently detected in the VBNC state. We believe that this unexpected result deserves particular attention because it constitutes new evidence which, together with the vibrio model, indicates that this may be the main mode of persistence of medically important bacteria in surface waters. The creation of an unexpected pathogen reservoir might possibly invalidate the culture methods currently used to assess the microbiological quality of surface waters in that...

Contrary to the common assumption that food has a negative impact on oral health, research has shown that several foods contain a number of components with antibacterial and antiplaque activity. These natural compounds may be useful for improving daily oral hygiene. In this study we evaluate the mode of antimicrobial action of fractions of mushroom and red chicory extracts on Prevotella intermedia, a periodontopathogenic bacterium. The minimal inhibitory concentration corresponded to 0.5x compared to the natural food concentration for both extracts. This concentration resulted in a bacteriostatic effect in mushroom extract and in a slightly bactericidal effect in chicory extract. Cell mass continued to increase even after division stopped. As regards macromolecular synthesis, DNA was almost totally inhibited upon addition of either mushroom or chicory extract, and RNA to a lesser extent, while protein synthesis continued. Cell elongation occurred after septum inhibition as documented by scanning electron microscopy and cell measurement. The morphogenetic effects are reminiscent of the mode of action of antibiotics such as quinolones or β-lactams. The discovery of an antibiotic-like mode of action suggests that these extracts can be advantageously employed for daily oral hygiene in formulations of cosmetic products such as mouthwashes and toothpastes.