Evaluating the accuracy and diagnostic value of CFW and a new fluorescent reagents, fluorescent brightener 85, for the diagnosis of vulvovaginal candidiasis

A study on the accuracy of a new fluorescent detection method for vaginal fungi

BACKGROUND

To investigate the positive rate and clinical applicability of liquid-based fungal method for detecting of vaginal fungi. We collect the secretions from the posterior vaginal fornix and the vaginal wall of 198 patients with clinically suspected fungi vaginitis patients for study.

METHODS

The vaginal fungi of vaginal discharge were detected by fluorescence method, i.e., by liquid-based thin-layer fungi fluorescence morphology staining detection kit (liquid-based fungal method), saline smear method and fungal culture method.

RESULTS

The positive rate of liquid-based fungal method, saline smear method was 50%, 25.75% respectively. The positive rate of liquid-based fungal method were 50%. The true positive rate of liquid-based fungal method (87.85%) was higher than that of saline smear method (45.79%, P < 0.001), which was easy to miss diagnosis. Moreover, the Kappa (K) of liquid-based fungal method was 0.81, and P < 0.01, which was statistically significant, indicating that the consistency of the two detection methods is good. Of the eight common symptoms of fungal vaginitis, the positive symptom coincidence rate of liquid-based fungal method was consistent with that of fungal culture method. It was also easier to see fungi under a microscope than with saline smear method.

CONCLUSION

The liquid-based fungal method has a high positive coincidence rate and accuracy in the detection of vaginal fungi, and it is convenient to operate and implement steps. Therefore, it may be applied in clinical practice. Or a combination of several detection methods can be used.

Comparison of Fungal Fluorescent Staining and ITS rDNA PCR-based Sequencing with Conventional Methods for Diagnosis of Onychomycosis

Accurate identification of fungal causes for onychomycosis is essential for proper treatment. Presently available laboratory methods show unreliable sensitivity; so there is a requirement for innovative detection techniques. The aim for this work was to assess the efficiencies of fluorescent staining and internal transcribed spacer (ITS) ribosomal DNA (rDNA) polymerase chain reaction (PCR)-based sequencing in comparison to conventional techniques for diagnosis of onychomycosis. Nail specimens obtained from 100 patients with clinically- diagnosed onychomycosis were analyzed. Nail scrapings or clippings were subjected to direct microscopic examination by KOH mount, culture by using Sabouraud’s dextrose agar and histopathological examination with periodic-acid Schiff (PAS). Collected specimens were subsequently examined by fluorescent staining and PCR-based sequencing (30 specimens only) to compare the feasibility, sensitivity and diagnostic accuracy for these two methods. The most frequently isolated fungi were yeasts (39/76: 51.3%), dermatophytes (24/76; 31.6%) and non-dermatophyte molds (NDMs) (13/76; 17.1%). Mixed mycotic infections were recovered from 6% of the collected nail specimens. The positive detection rates were significantly different between KOH examinations (52%), nail plate histology (55%), fungal culture (70%) and fluorescent staining (80%). Considering fungal culture as the gold standard, the most sensitive technique was PCR (100%) followed by fluorescent staining (89%), PAS staining (69%) while the least sensitive technique was KOH mount (53%). Fluorescence staining can be used as a rapid and high-yield technique for identification of fungi in the specimens. PCR-based sequencing was highly sensitive and faster compared to culture. Whenever possible, it enables species identification with higher adequacy.

Evaluating the accuracy and diagnostic value of CFW and a new fluorescent reagents, fluorescent brightener 85, for the diagnosis of vulvovaginal candidiasis

Background

Vulvovaginal candidiasis (VVC) is a common vaginitis in females. The commonly used diagnostic method, 10% potassium hydroxide (KOH) smear microscopy, makes it not very easy to recognize fungi.

Methods

Vaginal secretions were collected from clinically suspected VVC patients and divided into four groups and examined using KOH, CFW (Calcofluor White), FB 85(fluorescent brightener 85), and culture. The data were statistically analyzed.

Results

In total, 110 patients with suspected VVC were recruited. The positive rates of KOH, CFW, FB 85, and the culture method were 68.2%, 64.5%, 61.8%, and 77%, respectively. According to the McNemar test, there was no statistically significant difference between the KOH, CFW, and the FB 85 methods (p > 0.05). However, CFW had a shorter diagnosis time than the KOH method and had a statistically significant difference (p < 0.001). Moreover, CFW has the highest sensitivity, specificity, and accuracy. In morphological recognition, it was easier to recognize fungal structures with CFW and FB 85 than with the KOH.

Conclusions

The fluorescent method is a good method for the diagnosis of VVC. And the fungi can be found more quickly. Similar to CFW, FB 85 is also a potential good fluorescent reagent for the diagnosis of VVC and has potential value for application in clinical fungal infection diseases.