Identification of pathogenic yeast species by polymerase chain reaction amplification of the RPS0 gene intron fragment

Candida spp. Determination and Th1/Th2 Mixed Cytokine Profile in Oral Samples From HIV+ Patients With Chronic Periodontitis

Background: Chronic periodontitis (CP), caused by bacteria and fungi, appears in up to 66% of HIV-patients. The impact and association of HIV-treatment (HAART) and Candida itself has not been properly evaluated in the development and progression of CP. The immunopathogenesis is characterized by CD4⁺ T-cells activation and the balance between the T-helper 1 (Th1) and T-helper 2 (Th2) or a mixed cytokine profile. Currently, the associated causes of an immune response in HIV-patients with CP is controversial. Our aims were the determination of Candida spp. and cytokine profile in oral samples from HIV-positive patients with CP, considering the CD4⁺ T cells levels and HAART use.

Methods: From 500 HIV-positive patients evaluated, 228 patients were enrolled. Patients were separated in groups: (A) n = 53 (≤200 CD4⁺ T-cells on HAART); (B) n = 57 (≤200 CD4⁺ T-cells without HAART); (C) n = 50 (>200 CD4⁺ T-cells without HAART); (D) n = 68 (>200 CD4⁺ T-cells on HAART). Candida spp. were isolated from the oral biofilm and crevicular fluid in CHROMagar and confirmed by endpoint PCR. Cytokine levels were measured by beads-based immunoassay in saliva by flow cytometry.

Results: 147 patients (64.5%) were positive to Candida spp. and 204 strains were isolated; 138 (67.6%) were C. albicans and the remaining C. non-albicans species (C. glabrata>C. tropicalis>C. krusei>C. dubliniensis). In this study, CHROMagar showed good sensitivity (95%) but poor specificity (68%); since of the 152 samples identified as C. albicans, only 131 were confirmed by PCR; from the 10 samples identified as C. glabrata, only six were confirmed. Finally, of the 42 samples detected as C. tropicalis, only five were confirmed. When evaluating Candida spp. presence, group A and D had higher isolation, while group B had the highest species diversity. Whereas, group C had a significant reduction of Candida spp. Despite the presence of Candida and HAART, we found a Th1/Th2 hybrid profile in the saliva of patients with low CD4⁺ T-cell count (group A).

Conclusion: Abundance and diversity of the Candida spp. detected in HIV-patients with CP could be related to HAART and low CD4⁺ T-cells levels. Also, the immunosuppression might promote a local Th1/Th2 hybrid cytokine profile.

Pectinolytic enzymes-solid state fermentation, assay methods and applications in fruit juice industries: a review

A plethora of solid substrates, cultivation conditions and enzyme assay methods have been used for efficient production and estimation of polygalacturonase and pectin methylesterase enzymes. Recent developments in industrial biotechnology offer several opportunities for the utilization of low cost agro-industrial waste in Solid State Fermentation (SSF) for the pectinolytic enzyme production using fungi. Fruit waste mainly citrus fruit waste alone and along with other agro-industrial waste has been explored in SSF for enzyme production. Agro-industrial waste, due to the economic advantage of low procuring cost has been employed in SSF bioreactors for pectinolytic enzyme production. Acidic pectinases produced by fungi are utilized especially in food industries for clarification of fruit juices. This review focuses on the recent developments in SSF processes utilizing agro-industrial residues for polygalacturonase and pectin methylesterase production, their various assay methods and applications in fruit juice industries.

Molecular evidence on the occurrence of co-infection with Pichia guilliermondii and Wuchereria bancrofti in two filarial endemic districts of India

Background

Lymphatic filariasis (LF), a vector-borne parasitic disease, is endemic in several parts of India and mostly affects the poor or those with a low-income. The disease results in huge numbers of morbidities, disabilities, and deaths every year. Association of co-infection with other pathogens makes the condition more severe. Although co-infection is becoming a growing area of research, it is yet to emerge as a frontier research topic in filarial research specifically. This study reports the occurrence of a fungal infection in a large number of patients suffering from bancroftian filariasis in two districts of West Bengal, India.

Methods

Nocturnal blood samples from filarial patients containing parasites and fungus were initially co-cultured, and further the fungus was isolated and characterized. Molecular identification of the isolate was carried out by PCR-based selective amplification and sequencing of highly-conserved D1/D2 region of 26S rDNA, whereas pathogenicity was determined by amplification of the RPS0 gene. A phylogenetic tree was constructed to study the relationship between the isolate and common pathogenic yeasts. The isolate was studied for antibiotic sensitivity, whereas morphological characterization was performed by microscopic techniques.

Results

The isolate was identified as Pichia guilliermondii and this fungus was found to exist in co-infection with Wuchereria bancrofti in filarial patients. The fungus showed resistance to azole antifungals, griseofulvin, and, amphotericin B, whereas significant susceptibility was evident in cases of nystatin and cycloheximide. A total of 197 out of 222 patients showed this co-infection.

Conclusion

This study revealed, for the first time, that P. guilliermondii exists as a co-infection in microfilaraemic individuals living in a filarial endemic zone. The findings are important and have relevance to human health, especially for filarial patients.

Systematic internal transcribed spacer sequence analysis for identification of clinical mold isolates in diagnostic mycology: a 5-year study

The implementation of internal transcribed spacer (ITS) sequencing for routine identification of molds in the diagnostic mycology laboratory was analyzed in a 5-year study. All mold isolates (n = 6,900) recovered in our laboratory from 2005 to 2009 were included in this study. According to a defined work flow, which in addition to troublesome phenotypic identification takes clinical relevance into account, 233 isolates were subjected to ITS sequence analysis. Sequencing resulted in successful identification for 78.6% of the analyzed isolates (57.1% at species level, 21.5% at genus level). In comparison, extended in-depth phenotypic characterization of the isolates subjected to sequencing achieved taxonomic assignment for 47.6% of these, with a mere 13.3% at species level. Optimization of DNA extraction further improved the efficacy of molecular identification. This study is the first of its kind to testify to the systematic implementation of sequence-based identification procedures in the routine workup of mold isolates in the diagnostic mycology laboratory.

In vitro fungicidal activities of echinocandins against Candida metapsilosis, C. orthopsilosis, and C. parapsilosis evaluated by time-kill studies

Anidulafungin, micafungin, and caspofungin in vitro activities against Candida metapsilosis, C. orthopsilosis, and C. parapsilosis were evaluated by MICs and time-kill methods. All echinocandins showed lower MICs (mean MICs, 0.05 to 0.71 mg/liter) and the highest killing rates (-0.06 to -0.05 CFU/ml/h) for C. metapsilosis and C. orthopsilosis rather than for C. parapsilosis (mean MICs, 0.59 to 1.68 mg/liter). Micafungin and anidulafungin killing rates were greater than those determined for caspofungin. None of the echinocandins had fungicidal activity against C. parapsilosis.