One-Step Multiplex PCR for Simultaneous Detection and Identification of Eight Medically Important <i>Candida</i>Species

Recently, the incidence of Candida infections has substantially increased. Conventional identification methods for Candida species are technically difficult to conduct and cannot accurately distinguish each species. The purpose of the present study was to design primers to identify and detect simultaneously eight medically important Candida species using one-step multiplex PCR. PCR primers were designed based on partial sequences of intergenic spacer (IGS) and internal transcribed spacer (ITS) genes of eight medically important Candida species. These primers were able to distinguish each Candida species and did not display cross-reactivity with representative Candida species other than the eight Candida species. Moreover, our developed one-step multiplex PCR method is accurate, specific, cost-effective, time-saving, and worked without requiring DNA extraction.

Novel Isolation and Identification Methods for Veillonella Species Involved in Halitosis

Purpose: The purpose of the present study was to develop a novel selective medium (OVSM) and useful identification method for oral Veillonella species, to assess the prevalence of this species using the selective medium, and to investigate whether the monitoring of oral Veillonella species levels is useful as a clinical indicator for the diagnosis of halitosis. Methods: To examine bacterial populations in the oral cavity, a novel selective medium (OVSM) and multiplex PCR method were developed for isolating and identifying oral Veillonella species. OVSM consists of tryptic soy agar, sheep blood, sodium lactate, vancomycin, and oxacillin. Results: Oral Veillonella species grew well on OVSM. Oral Veillonella species accounted for 5.4% and 27.2%, respectively, of all bacteria in the tongue biofilm samples of healthy and halitosis subjects. Oral Veillonella species produced larger amounts of volatile sulfur compounds than other representative oral bacteria. Conclusion: These results indicate that monitoring the levels of these organisms is useful as a clinical indicator for the diagnosis of halitosis.

Origin of Candida albicans in Human Oral Cavity

Purpose: Candida albicans is regarded as a part of normal flora in the human oral cavity. However, it remains unclear whether the genus Candida, especially C. albicans, is an oral resident microorganism and causes marital infection or not. The purpose of the present study was to elucidate the origin of oral C. albicans by investigating the colonization and infection route to oral cavities of this organism with arbitrarily primed polymerase chain reaction (AP-PCR). Methods: After C. albicans was isolated from four subjects (average age: 42.2, range: 33 - 56), the isolations of this organism from them were performed six months later again. To investigate whether C. albicans is an oral resident microorganism, the genotype homology of each C. albicans isolates that were isolated twice from the same subjects was compared. Moreover, C. albicans was isolated from five pairs of married couples (average period of cohabitation: 12.4 years, range: 5 - 31). To investigate whether C. albicans causes marital infection, the genotype homology of C. albicans isolates that were isolated from each pair of married couples was compared. Results: AP-PCR patterns of C. albicans that were isolated from each subject at o month and after 6 months showed the identical genotypes among each individual. C. albicans isolates from five pairs of married couples showed the identical genotypes between a husband and wife of each pair on AP-PCR. Conclusion: These results indicated that C. albicans was an oral resident microorganism and caused the marital infection.