Effect of Xylitol on various Oral bacteria

Xylitol is a five-carbon sugar alcohol that reduces the incidence of caries by inhibiting the growth of oral streptococci, including Streptococcus mutans. Since xylitol is transported via the fructose phosphotransferase system, we hypothesized that it could also affect the growth of other oral bacteria strains. We tested the effects of xylitol against non-periodontopathogenic oral bacteria frequently found in healthy subjects as well as periodontopathogens including Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia. With 5% xylitol, Streptococcus vestibularis and Gemella morbillorum showed marked growth inhibition. With 10% xylitol, all of the tested periodontopathogens and Actinomyces naeslundii showed marked growth inhibition, whereas the growth inhibition of Neisseria mucosa, Neisseria sicca and Veillonella parvula was mild only. Xylitol is a widely used sweetener and the concentration used in our experiment is easily achieved in the oral cavity. If xylitol reduces the growth of periodontopathogens more preferentially, it could also reduce the prevalence of these pathogens and have clinical utility in the prevention or treatment of periodontal disease.

Serotyping of Neisseria meningitides in conscripts with meningitis admitted to five military hospital in Tehran between September 2004 and September 2006

Meningococcal meningitis is one of the most feared disorders with high rate morbidity and mortality. There is no exact information of meningococcal meningitis incidence in military personnel. Obligate vaccination of the military with meningococcal vaccine is a strategy with the potency to provide active protection of the conscripts before being dispatched to training centers. Although sporadic cases of meningitis in conscripts occurred The aim of this study was serotyping of the bacterium; Neisseria meningitides isolated from patients with meningitis which admited to five military Hospitals. In this cross- sectional study for determination of meningococcal meningitis serotypes in conscripts submit to five military hospitals the investigation was designed and carried out from September 2003 to September 2006. In this period, 12 cerebrospinal fluids of conscripts with clinical signs and symptoms of meningitis were collected, and the laboratory tests were done. In this study enriched Thayer Martin medium and standard bacteriological methods were used. The sample without bacterial cells or PMNs were centrifuged [10000 xg for 5 min], The precipitate was cultured and direct smear was performed.Isolated bacterial strains was recognized by biochemical tests, and Neisseria meningitides strains were serotyped by specific antiserum. During the study, 12 cases of meningitis in conscripts were seen. Neisseria meningitides was isolated only from 6 patients. Serotyping analysis revealed that 5 strains belong to Serotype C and 1 strain was to serotype B. Neisseria sica was isolated from one patient. In three patients there was no bacteriological evidence. In two patients, consumption of antibiotic before lumbar puncture results to no bacterial growth, but direct smear showed gram negative diplococci. In one patient recurrent meningococcal infection has occurred. Complement components analysis revealed deficiency in C3, C4 and CH50 [the rate was below 80 mg per deciliter]. The results of this study showed that, Neisseria meningitides was isolated from six patients which are all conscripts. It is necessary to find the reasons that why vaccinated conscripts infected by Neisseria meningitides serotype C. Further analysis showed that, five patients had complement deficiency and further research is necessary. However, 6 Neisseria meningitides strains were isolated from meningococcal vaccinated conscripts around the country [Tehran, Shiraz, Yazd and Oslavieh] in the period of study. Based on the findings of this study, effectiveness of the vaccine was desirable and the disease had been controlled in this population group. Because of complements deficiency in patients with meningococcal meningitis, other preventing methods for eradication of disease are necessary

Microbiological analysis of radiographic films and tubes in private and public dental radiographic centres in Yazd [2001]

In dental radiography, there are specific potentials to transmit infection. The goal of this research was to investigate radiographic films and tubes microbiologically in private and pudic dental radiographic centres in the city of Yazd. In this cross-sectional descriptive study [2001], all 13 public and private centres with totally 21 dental radiography machines were investigated. First, sample was collected from different areas of radiography tubes and films' covers by a sterile wetswap. All samples were kept in Tayoglycolate culture media and then put in 37°C incubator in microbiology laboratory. The cloudiness was checked every 24 hours. Data were analyzed using Extended Fisher test. In samples collected from public radiography centres, microbial infections with pseudomonas aeruginosa, Staphylococcus epidermidis, Aspergillus niger and alkagenous were detected probably resulted from hospital infections and healthy carries among hospital personnel. In private centres infections with microbes such as Neisseria sicca, Staphylococcus epidermidis and Bacillus subtilis were detected, a probable consequence of normal flora in the environment. Films' covers in public centres were infected with Staphylococcus aureus, Staphylococcus hemolyticus, Neisseriasicca and Staphylococcus epidermidis probably due to contact with healthy carriers. The methods applied in Yazd radiographic centres, especially the public ones, are completely different from the standards recommended by ADA and CDC. Therefore, our society is definitely exposed to cross-sectional infections along radiographic clinics