Biofilm production in oralCandidaisolates from HIV-positive individuals from Pune, India

Antimicrobial photodynamic therapy for oral Candida infection in adult AIDS patients: A pilot clinical trial

BACKGROUND

Antimicrobial photodynamic therapy (aPDT) using methylene blue (MB) plus potassium iodide (KI) has been shown to be effective in killing Candida albicans in many in vitro and in vivo studies, however, there are limited reports of clinical investigations. This study aimed to explore the clinical application of aPDT with MB plus KI for the treatment of oral infection caused by C. albicans in adult acquired immune deficiency syndrome (AIDS) patients.

METHODS

A total of 21 adult AIDS patients with C. albicans oral candidiasis were divided into two groups according to MB concentration and received two consecutive aPDT treatments. Immediately before and after the aPDT treatments, C. albicans yeast isolates were recovered to measure the colony-forming units per mL (CFU/mL), biofilm formation, and to analyze the 25S rDNA genotype. Patients were assessed for the clinical recovery of oral lesions and improvement of symptoms.

RESULTS

The Log₁₀ CFU/mL of C. albicans decreased significantly after the second aPDT but not the first aPDT. There was no significant difference between the two MB concentrations. Both aPDT protocols decreased the oral lesions and clinical symptoms with no significant difference after 2-fraction aPDT. The biofilm formation of C. albicans isolates did not change before and after aPDT. The killing efficiency of 2-fraction-aPDT was not associated with either biofilm formation or 25S rDNA genotype.

CONCLUSIONS

Two-fraction-aPDT with MB plus KI could reduce the number of viable C. albicans fungal cells and improve the clinical symptoms of oral candidiasis in adult AIDS patients, regardless of the biofilm formation or 25S rDNA genotype of infected C. albicans isolates.

Microbial interactions and immunity response in oral Candida species

Oral candidiasis are among the most common noncommunicable diseases, related with serious local and systemic illnesses. Although these infections can occur in all kinds of patients, they are more recurrent in immunosuppressed ones such as patients with HIV, hepatitis, cancer or under long antimicrobial treatments. Candida albicans continues to be the most frequently identified Candida spp. in these disorders, but other non-C. albicans Candida are rising. Understanding the immune responses involved in oral Candida spp. infections is a key feature to a successful treatment and to the design of novel therapies. In this review, we performed a literature search in PubMed and WoS, in order to examine and analyze common oral Candida spp.-bacteria/Candida-Candida interactions and the host immunity response in oral candidiasis.

Oral mycobiome identification in atopic dermatitis, leukemia, and HIV patients - a systematic review

INTRODUCTION

Oral mycobiome profiling is important to understand host-pathogen interactions that occur in various diseases. Invasive fungal infections are particularly relevant for patients who have received chemotherapy and for those who have HIV infection. In addition, changes in fungal microbiota are associated with the worsening of chronic conditions like atopic dermatitis (AD). This work aims, through a systematic review, to analyze the methods used in previous studies to identify oral fungi and their most frequent species in patients with the following conditions: HIV infection, leukemia, and atopic dermatitis.

METHODS

A literature search was performed on several different databases. Inclusion criteria were: written in English or Portuguese; published between September 2009 and September 2019; analyzed oral fungi of HIV-infected, leukemia, or AD patients.

RESULTS

21 studies were included and the most identified species was Candida. The predominant methods of identification were morphological (13/21) and sugar fermentation and assimilation tests (11/21). Polymerase chain reaction (PCR) was the most used molecular method (8/21) followed by sequencing techniques (3/21).

CONCLUSIONS

Although morphological and biochemical tests are still used, they are associated with high-throughput sequencing techniques, due to their accuracy and time saving for profiling the predominant species in oral mycobiome.

Virulence factors and genetic variability of vaginal Candida albicans isolates from HIV-infected women in the post-highly active antiretroviral era

Vulvovaginal candidiasis (VVC) in HIV-infected (HIV+) women is a serious public health problem. However, little is known about the virulence mechanisms of vaginal Candida albicans from HIV+ women in the post-highly active antiretroviral therapy (HAART) era. Here, we report a comparative analysis of the expression of key virulence factors and genetic variability of 26 vaginal C. albicans strains isolated from HIV+ women undergoing HAART and 18 from HIV-uninfected (HIV-) women. In general, we observed that C. albicans from HIV+ women receiving HAART showed lower expression of virulence factors compared with C. albicans from HIV- women, except for the proteinase activity which is highly expressed. The results in HIV-women further suggest that virulence factors appear to be expressed in response to the yeast stress, in the presence of an adequate immune response. Furthermore, the RAPD results showed a high heterogeneity among isolates from both groups of women. These findings in HIV+ women using HAART will help to improve the monitoring of vaginal yeast infections and the quality of life of patients.

The Evaluation of the virulence factors of clinical Candida isolates and the anti-biofilm activity of Elettaria cardamomum against multi-drug resistant Candida albicans

Background and Purpose:

Today, treatment of life-threatening fungal infections, caused by Candida species, has become a major problem. In the present study, we aimed to evaluate the antifungal susceptibility patterns of different clinical Candida isolates, determine the virulence factors in multi-drug resistant (MDR) Candida species, and assess the anti-biofilm activity of Elettaria cardamomum against MDR Candida species.

Materials and Methods:

A total of 202 isolates from different Candida species were obtained from three governmental hospitals in Senthamangalam, Tiruchengode, and Namakkal, Tamil Nadu, India. The isolates were identified, using conventional methods. Candida species were tested for virulence factors such as biofilm, protease, and phospholipase activity. The minimum inhibitory concentration (MIC) of Elettaria cardamomum against MDR biofilm-forming C. albicans was determined, using plate and tube methods.

Results:

The identified Candida isolates (n=202) were C. albicans (74/202), C. glabrata (53/202), C. parapsilosis (44/202), C. tropicalis (15/202), and C. dubliniensis (16/202). The isolates were subjected to antifungal susceptibility testing and the virulence factors were determined. In terms of biofilm production, non-C. albicans species such as C. dubliniensis showed 75% activity. Also, regarding protease activity, C. parapsilosis (75%) showed the highest percentage of protease production. In addition, Candida species showed strong positivity for phospholipase activity (62.87%). In the MIC method, the acetonic extract completely inhibited biofilm production at a concentration of 125 µl (56.25 µg). In comparison with the ethanolic extract, the acetonic extract showed major activity against biofilm production.

Conclusion:

Based on the findings, pathogenic C. albicans species were inhibited by the ethanolic and acetonic extracts of E. cardamomum. In recent years, MDR and biofilm-forming pathogenic Candida species have been increasingly detected in clinical settings. Therefore, herbal derivatives might contribute to the treatment of infections without causing any side-effects and prevent the associated mortality.

Estimation of biofilm, proteinase & phospholipase production of the Candida species isolated from the oropharyngeal samples in HIV-infected patients

BACKGROUND & OBJECTIVES

Candida, the most common opportunistic infection in acquired immunodeficiency syndrome (AIDS), attributes its pathogenicity to its virulence factors, mainly the biofilms, the proteinases and the phospholipases. There is a significant interplay of these factors during the HIV infection. This study was aimed to estimate the biofilm, proteinase and phospholipase production in Candida species isolated from the oropharyngeal samples in the HIV-infected patients.

METHODS

A total of 126 consecutive HIV-positive patients were screened for Candida growth using oropharyngeal swabs. Identification was done by Gram staining, germ tube test, chlamydospore identification, chromagar and biochemical tests on Vitek 2. Biofilm production was observed on Sabouraud's dextrose broth with glucose, phospholipase production in egg yolk agar medium and proteinase production in bovine serum albumin agar medium.

RESULTS

Of a total of 126 patients, 53 (42.06%) showed Candida growth: Candida albicans (n=46, 86.8%) was most common followed by the non-albicans Candida (NAC) (n=7, 13.93%). Of a total 33 (62.3%) biofilm positive isolates, significant production was observed in the NAC species (P <0.05). C. albicans reported the highest phospholipase (n=37/41, 90.24%) and proteinase (n=37/43, 86%) activities in a total of 41 (77%) phospholipase positive and 43 (81.1%) proteinase positive isolates.

INTERPRETATION & CONCLUSIONS

Although C. albicans was the most common Candida species identified in HIV positive patients, the emergence of NAC was of special concern. Virulence factors such as biofilms, proteinases and phospholipases were noted in both these groups. Further research is required for better understanding of the pathogenic role of Candida species so as to aid in therapeutic interventions.

Candida species from oral cavity of HIV-infected children exhibit reduced virulence factors in the HAART era

This study aimed to assess, in vitro, the biofilm viability and the phospholipase and protease production of Candida spp. from the saliva of HIV infected children and healthy controls, and to correlate the results with the use of medical data. A total of 79 isolates were analyzed: 48 Candida albicans isolates (33/15) and 20 Candida parapsilosis sensu lato complex isolates (12/8) (from HIV/control patients, respectively), and 8 Candida krusei, 1 Candida tropicalis, 1 Candida dubliniensis and 1 Candida guilliermondii from HIV patients. The XTT (2, 3-bis (2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-Carboxanilide) reduction assay analyzed the biofilm viability. Phospholipase and protease assays were performed using the egg yolk and Bovine Serum Albumin agar plate methods, respectively. All isolates were able to form biofilm with cell viability. Quantitatively, Candida isolates from both groups presented a similar ability to form biofilm (p > 0.05). The biofilm viability activity was higher in C. albicans isolates than in non-albicans Candida isolates (p < 0.05) for both groups. Phospholipase activity was detected in 32 isolates (40.5%) and it was significantly higher in the HIV group (p = 0.006). Protease activity was detected in 66 isolates (84.8%) and most of them were relatively/very strong producers. No statistical association with medical data was found in the HIV group. Although Candida spp. isolates from HIV-positive children presented higher phospholipase production, in vitro they exhibited reduced virulence factors compared to isolates from healthy individuals. This finding may enlighten the role played by immunosuppression in the modulation of Candida virulence attributes.

Comparison Between Biofilm Production, Phospholipase and Haemolytic Activity of Different Species of Candida Isolated from Dental Caries Lesions in Children

INTRODUCTION

C.albicans is the most commonly isolated fungal pathogen in the oral cavity, but isolation of non-albicans Candida is increasing in recent years. We wish to demonstrate the virulence factors of Candida spp. isolated from the dental caries lesion of the children as presence of virulence factors determines the pathogenic potential of any microorganism.

AIM

To compare biofilm production, phospholipase and haemolytic activity of C.albicans with that of non-albicans species of Candida isolated from dental caries lesions of children to evaluate the role of non- albicans species of Candida in formation of dental caries.

MATERIALS AND METHODS

Oral swabs were collected from caries lesion of 100 school children of age 5-10 years with dental caries. Candida isolates were tested for biofilm production, phospholipase and haemolytic activity. Statistical analysis was done by Chi-Square test and Mann-Whitney U test wherever applicable using SPSS version 11.5.

RESULTS

Out of the 100 children with dental caries 37 were positive for Candida by smear or culture and 31 by culture. C.albicans was the most prevalent isolate followed by C.krusei, C.tropicalis and C.albicans. Out of 21 C.albicans isolates, 10 (47.6%) showed phospholipase activity and 18 (85.71%) produced biofilm. Of the 10 non-albicans strains, 5 (50%) showed phospholipase activity and 6 (60%) produced biofilm. All isolates of Candida produced haemolysin (100%).

CONCLUSION

There was no statistically relevant difference between the virulence factor production by C.albicans and non-albicans species of Candida. In other words, our study shows that both C.albicans and non-albicans species of Candida isolated from caries lesions of the children, produce these virulence factors. So we can say that non-albicans species of Candida also are involved in caries formation.