Antimicrobial photodynamic therapy: photodynamic antimicrobial effects of malachite green on Staphylococcus, enterobacteriaceae, and Candida.

OBJECTIVE: This study investigated in vitro the photodynamic antimicrobial effects of the photosensitizer malachite green on clinical strains of Staphylococcus, Enterobacteriaceae, and Candida. MATERIALS AND METHODS: Thirty-six microbial strains isolated from the oral cavity of patients undergoing prolonged antibiotic therapy, including 12 Staphylococcus, 12 Enterobacteriaceae, and 12 Candida strains, were studied. The number of cells of each microorganism was standardized to 10(6) cells/mL. Twenty-four assays were carried out for each strain according to the following experimental conditions: gallium-aluminum-arsenide laser and photosensitizer (n = 6, L+P+), laser and physiologic solution (n = 6, L+P-), photosensitizer (n = 6, L-P+), and physiologic solution (n = 6, L-P-). Next, cultures were prepared on brain-heart infusion agar for the growth of Staphylococcus and Enterobacteriaceae, and on Sabouraud dextrose agar for the growth of Candida, and incubated for 48 h at 37 degrees C. The results are reported as the number of colony-forming units (CFU/mL) and were analyzed with analysis of variance and the Tukey test. RESULTS: The Staphylococcus, enterobacterial, and Candida strains were sensitive to photodynamic therapy with malachite green (L+P+). A reduction of approximately 7 log(10) for Staphylococcus, 6 log(10) for enterobacteria, and 0.5 log(10) for the genus Candida. Significant statistical differences were observed between the L+P+ groups and the control groups (L-P-). CONCLUSION: The Staphylococcus, Enterobacteriaceae, and Candida strains studied were sensitive to photodynamic therapy with malachite green.

Frequency of Candida spp. in the oral cavity of Brazilian HIV-positive patients and correlation with CD4 cell counts and viral load.

The aim of this study was to evaluate the prevalence of Candida spp., and particularly C. dubliniensis, among oral isolates from Brazilian HIV-positive patients correlating these results with CD4 cell counts and viral load. Forty-five individuals (23 female and 22 male) diagnosed as HIV-positive by ELISA and Western-blot, under anti-retroviral therapy for at least 1 year and without oral candidosis signals were included in the study. The control group was constituted by 45 healthy individuals, matched to the test group in relation to age, gender, and oral conditions. Oral rinses were collected and the identification was performed by phenotypic tests. The existence of C. dubliniensis among the isolates was analyzed using a validated multiplex PCR assay. Candida spp. were detected at significantly higher number in the oral cavity of HIV-positive patients in relation to the controls (P = 0.0008). C. albicans was the most frequently isolated species in both groups. In the HIV group, C. glabrata, C. lipolytica, C. krusei, C. guilliermondii, and C. parapsilosis were also identified. In the control group, we additionally identified C. tropicalis and C. dubliniensis. Two isolates (1.9%, 2/108) from control individuals were identified as C. dubliniensis and this species was not verified in the HIV group. Candida spp. counts were statistically lower (P = 0.0230) in the oral cavity of patients with low viral load (<400 copies/mm(3)). Candida spp. counts did not differ statistically among groups with different levels of CD4 cells counts (P = 0.1068).