Biofilms have been implicated as reservoirs for bacterial contamination of water delivered by dental air-water syringes. A 6-month study was done of bacterial colonization and biofilm formation in plastic water supply lines connected to dental air-water syringes. Changes in biofilm flora were observed by both scanning electron microscopy and bacteriologic culture. By day 7, many rod- and spiral-shaped bacteria had colonized the ridged surface of the luminal wall of the tubing, as revealed by scanning electron microscopy. By day 30, individual microcolonies were embedded in extracellular polymeric material. By day 120, these microcolonies had begun to coalesce, and by day 180 the biofilm had developed into a multilayered, heterogeneous mixture of microcolonies. The mean aerobic plate counts of colony-forming units of planktonic and biofilm populations were, in log10 values, 5.9 +/- 0.54/mL and 4.2 +/- 0.82/cm2, respectively. Early colonizers were predominantly Pseudomonas spp., but included Pasteurella, Moraxella, Ochrobactrum, and Aeromonas spp. Flavobacterium and Acinetobacter spp. were observed later. Many of these organisms are opportunistic pathogens. These results demonstrate the longitudinal dynamics of biofilm formation.

F. nucleatum is the most commonly isolated microorganism from subgingival plaque, but the role of this microorganism in periodontal diseases remains undefined. Arbitrarily primed polymerase chain reaction (AP-PCR) was evaluated as a method for fingerprinting F. nucleatum isolates and for use in clonal analysis. Pulsed field gel electrophoresis was used to further differentiate F. nucleatum isolates, with identical AP-PCR patterns. Extremely heterogeneous AP-PCR fingerprints were observed among the 98 F. nucleatum isolates, with 36 different genotypes observed with primer C1 and 30 different genotype detected with primer C2. Combining the results of the AP-PCR genotype analysis from C1 and C2 primer amplifications revealed that up to 7 different genotypes could be distinguished from isolates from the same oral cavity and that up to 4 different genotypes were observed within a single site. An intense amplicon at approximately 450 bp generated in AP-PCR amplification with primer C2 was associated with F. nucleatum subsp. nucleatum (ATCC 25586) and with 15 F. nucleatum isolates from diseased sites and 2 isolates from healthy sites. Pulsed field gel electrophoresis confirmed the AP-PCR genotypes and demonstrated increased discriminatory power over AP-PCR. The results indicated that AP-PCR and pulsed field gel electrophoresis provide a simple and sensitive means for differentiating oral F. nucleatum isolates and further demonstrate the heterogeneity of this species. These techniques may serve as useful tools in the clonal and epidemiological analysis of F. nucleatum isolates, which may help define the role of these microorganisms in periodontal diseases.

Eubacterium species are gram-positive anaerobic rods that are frequently isolated from subgingival plaque of periodontal pockets. Five Eubacterium species were tested for their ability to coaggregate with 33 oral bacterial strains. Using visual and turbidimetric assays, coaggregation was observed among Eubacterium brachy, Eubacterium nodatum, Eubacterium alactolyticum and Eubacterium limosum strains only when tested with Fusobacterium nucleatum strains; Eubacterium saburreum displayed only weak coaggregation ability. Coaggregation between F. nucleatum and the Eubacterium species was observed over a wide range of concentrations of each organism. The F. nucleatum strains contained a heat labile and the Eubacterium species a heat stabile coaggregation receptor. Arginine, histidine, lysine and glycine inhibited the coaggregation between F. nucleatum and the Eubacterium species. Sugars and other amino acids tested did not inhibit the observed coaggregation. Rabbit anti-F. nucleatum serum completely inhibited coaggregation, but anti-E. brachy serum and normal rabbit serum did not. As these anaerobic microorganisms are frequently isolated from the same oral lesions, the surface interactions observed may be important in the pathogenesis of these polymicrobic infections.

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It is known that there are many factors which affect the removal of metals in conventional sewage treatment plant. The purpose of this research was the determination of ten metals (Fe, Cu, Zn, Mn, Pb, Cd, Cr, Ni, V, Li) in the wastewater of the town of Kavala (80,000 population), at the inlet and at the outlet of the waste water treatment plant under different conditions (strong rainfall, an average day and during holidays). The previously mentioned conditions showed the effect they have on the concentration of heavy metals in untreated waste water (the strong rainfall increases the concentrations of the Fe, Cu, Zn, Cr and Pb, and the holidays reduces the concentrations of the Fe, Cu, Zn, Mn, Ni, Pb and Cd) and the removal ability of metals during the treatment.