New system for detecting vulvovaginal candidiasis

New system for detecting vulvovaginal candidiasis | Image Credit: © New Africa - © New Africa - stock.adobe.com.

According to a recent study published in Biosensors, an integrated and multi-target nucleic acid analysis system effectively identifies vulvovaginal candidiasis (VVC).

VVC, presenting as vulvovaginal inflammation and Candida species presence, is the second most common cause of vaginitis symptoms, with about 75% of healthy adult women experiencing at least 1 VVC episode in their lifetime. Half of all women with a VVC experience will have another experience later in life.

Identifying the presence of Candida species is the most reliable method of diagnosing VVC. This is often accomplished through low-cost and rapid microscopic examination. However, this method has low sensitivity if clinicians are lacking experience or specimens are lacking quality. 

Fungal culturing is another method of identifying Candida species, but this method takes at least 1 to 2 days and is laborious. A rapid and isothermal method called loop-mediated isothermal amplification (LAMP) may also be able to identify Candida species. More data on LAMP is necessary to understand if it may be used to identify different Candida species.

Investigators evaluated the efficacy of an integrated and multi-targeted rapid sample processing and testing (RPT) system for rapidly diagnosing VVC. A rapid sample processing cassette and a rapid nucleic acid analysis device made up the RPT system examined, and it was powered using mains line or battery.

The processing cassette was made using a liquid control unit, heating and vibration unit, small injector, and reagent storage unit. The nucleic acid analysis devise was made using a substrate chip with microfluidic channels and a cover with double-faced adhesive tape.

PrimerExplorer V5 was used to design the mycological typing LAMP primers, with synthesis accomplished by Sangon Biotech. Primers were screened for sensitivity and specificity, and primer validation was accomplished using standard strains of microorganisms. A WarmStart LAMP Kit was used to conduct the LAMP assay.

When comparing the nucleic acid extraction of LAMP and PCR assays, it was found that for the LAMP assay, the cassette had similar sensitivity for detecting Candida albicans and Candida tropicalis as the kit and was more efficient in detecting Candida glabrata and Candida parapsilosis by 1 magnitude. Similar results were found for the PCR assay, showing strong efficacy from the LAMP assay.

The RPT system also showed clinically significant efficacy, being able to detect C. tropicalisat concentrations as low as 3.31 × 102 CFU/mL.C. albicans, C. glabrata, and C. parapsilosis sensitivities with the RPT system were 2.75 × 103 CFU/mL, 4.03 × 102 CFU/mL, and 3.48 × 102 CFU/mL respectively. This indicated strong efficacy using the RPT system.

An RPT system could return a diagnosis within 60 minutes, making it a fast and efficient tool for detecting Candida species. This may make the RPT system valuable for diagnosing VVC in women.

Reference

Jin X, Li M, Mao Z, et al.An integrated and multi-target nucleic acid isothermal analysis system for rapid diagnosis of vulvovaginal candidiasis. Biosensors (Basel). 2023;13(5):559. doi:10.3390/bios13050559