Detection ofCandidain Concentrated Oral Rinse Cultures by Real-Time PCR

Abstract

The incidence of oral candidosis has increased in recent years, largely as a result of the emergence of human immunodeficiency virus infection and the more widespread use of immunosuppressive chemotherapy. This development has been associated with a need for more reliable methods for the detection of Candida. The present study assessed the performance of a real-time PCR and two block-based PCRs for the detection of Candida in 193 concentrated oral rinse culture (CRC) specimens. A total of 102 CRC specimens were positive by culture for Candida; and 96, 90, and 75 of these were also positive by real-time, N18-specific, and internal transcribed spacer (ITS)-specific PCRs, respectively. The five false-negative results by the real-time PCR were all non-Candida albicans positive by culture. Of the 91 culture-negative CRC specimens, 20, 41, and 44 were positive by the real-time PCR and the N18-and ITS-specific PCRs, respectively. All three PCRs detected fungal DNA in 8 culture-negative CRC specimens, with a further 30 being positive by two of the three PCRs. A total of 32 CRC specimens were Candida free by all methods. In summary, a real-time PCR that provides a sensitive, specific, and rapid alternative technique for detection of Candida in the mouth is described.

Usefulness of a commercial enzyme-linked immunosorbent assay kit for Candida mannan antigen for detecting Candida in oral rinse solutions

“…White et al used real-time polymerase chain reaction (PCR) to detect Candida in concentrated oral rinse cultures and reported that 97 (67%) of the 145 clinical samples and 17 (38%) of the 48 healthy control samples were positive for Candida. 3 Liguori et al used a multiplex PCR assay directly for oral rinse solutions and reported that 64 (82.1%) of 78 samples from symptomatic patients were positive for Candida. 7 Our results are compatible with their results.…”

“…It is an opportunistic disease and the incidence of oral candidiasis has increased as a result of the escalation of human immunodeficiency virus infection and the more widespread use of immunosuppressive chemotherapy. 3 In addition, higher incidences of Candida isolation from oral conditions not previously associated with Candida infection have been reported. 3 These include high incidences of Candida in the mouth of patients with lichen planus, burning mouth syndrome, dry mouth, and leukoplakia.…”

“…3 These include high incidences of Candida in the mouth of patients with lichen planus, burning mouth syndrome, dry mouth, and leukoplakia. 3,4,5 The significance of Candida in these patients is uncertain, but it has been attracting increasing interest.…”

“…In recent years, numerous DNA-based methods have been reported to detect oral Candida species. 3,7 However, they are still laborious and costly, and have technical problems such as the risk of contamination. The methods for DNA extraction and detection should be both standardized and simplified to introduce a molecular diagnostic method for the routine examination of oral samples.…”

“…However, many studies have pointed out the low positivity of cultures. 3,6,7 Clinicians and researchers require a reliable and sensitive method to detect oral Candida. In recent years, numerous DNA-based methods have been reported to detect oral Candida species.…”