Oral colonization by Candida species and associated factors in HIV-infected patients in Ahvaz, southwest Iran

Antifungal Susceptibility and Candida sp. Biofilm Production in Clinical Isolates of HIV-Positive Brazilian Patients under HAART Therapy

The aim of the present study was to characterize biofilms formed by Candida spp. clinical isolates (n = 19), isolated from the oral mucosa of HIV-positive patients. For characterizing the biofilms formed by several Candida sp. strains, isolated from HIV-positive patients, in terms of formed biomass, matrix composition and antifungal susceptibility profile, clinical isolates (n = 19) were collected from oral mucosa and identified. The biofilm of the samples was cultured with fluconazole (1250 mg/L), voriconazole (800 mg/L), anidulafungin (2 mg/L) or amphotericin B (2 mg/L). Afterwards, the quantification of the total biomass was performed using crystal violet assay, while the proteins and carbohydrates levels were quantified in the matrix. The results showed a predominance of C. albicans, followed by C. krusei. Around 58% of the Candida spp. biofilm had susceptibility to fluconazole and voriconazole (800 mg/L), 53% to anidulafungin and 74% to amphotericin B. C. krusei presented both the lowest and the highest biofilm matrix contents in polysaccharides and proteins. The low resistance to antifungal agents reported here was probably due to the fact that none of the participants had a prolonged exposure to these antifungals. A predominance of less virulent Candida spp. strains with low or no resistance to antifungals was observed. This can be attributed to a low fungal selective pressure. This most probably happened due to a low fungal selective pressure but also due to a good adherence to HAART therapy, which guarantees a stable and stronger immune patient response.

Exploring the diversity of uncommon oral yeast species and associated risk factors among substance abusers in southwestern Iran

Yeast species are a group of coexistent microorganisms in the oral cavity that can cause opportunistic infections in vulnerable individuals, including addicts. This study aimed to identify the yeast species profile responsible for oral yeast colonization (OYC) and the associated risk factors in patients with substance use disorder (SUD) in Ahvaz, Iran. Oral samples were collected from drug users hospitalized in 12 addiction treatment centers, and the related clinical information was mined. Oral yeast species were identified using 21-plex PCR and sequencing of the internal transcribed spacer region (ITS1-5.8S-ITS2). A total of 244 yeast strains were identified from 245 individuals with substance abuse. Candida albicans was the most common species (37.7%) and non-albicans Candida was responsible for 57.7% of OYC, primarily C. dubliniensis (33.2%) and C. glabrata (11.9%). Moreover, uncommon oral yeasts constituted 5.3% of species, including Saccharomyces cerevisiae, Clavispora lusitaniae, Pichia kluyveri, Geotrichum candidum, Magnusiomyces capitatus, Hanseniospora opuntiae, Wickerhamomyces subpelliculosus, Trichosporon asahii, and Aureobasidium pullulans. Importantly, OYC exhibited associations with such factors as duration of drug use, daily drug consumption rate, opioid utilization, oral drug administration, and the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) score. The present study is the pioneering investigation revealing the prevalence and diversity of oral yeast species, along with associated risk factors, in individuals with SUD in southwestern Iran. Furthermore, it underscores the importance of developing efficient and cost-effective diagnostic methods tailored for resource-constrained settings.

Meyerozyma guilliermondii species complex: review of current epidemiology, antifungal resistance, and mechanisms

Meyerozyma guilliermondii has been accepted as a complex composed of Meyerozyma guilliermondii, Meyerozyma carpophila, and Meyerozyma caribbica. M. guilliermondii is a saprophyte detected on human mucosa and skin. It can lead to serious infections in patients with risk factors like chemotherapy, immunodeficiency, gastrointestinal or cardiovascular surgery, and oncology disorders. Most deaths related to M. guilliermondii infections occur in individuals with malignancy. In recent decades, incidence of M. guilliermondii infections is increased. Sensitivity of this microorganism to conventional antifungals (e.g., amphotericin B, fluconazole, micafungin and anidulafungin) was reduced. Prophylactic and empirical uses of these drugs are linked to elevated minimal inhibitory concentrations (MICs) of M. guilliermondii. Drug resistance has concerned many researchers across the world. They are attempting to discover appropriate solution to combat this challenge. This study reviews the most important mechanisms of resistance to antifungals developed by in M. guilliermondii species complex.

Neglected mycobiome in HIV infection: Alterations, common fungal diseases and antifungal immunity

Human immunodeficiency virus (HIV) infection might have effects on both the human bacteriome and mycobiome. Although many studies have focused on alteration of the bacteriome in HIV infection, only a handful of studies have also characterized the composition of the mycobiome in HIV-infected individuals. Studies have shown that compromised immunity in HIV infection might contribute to the development of opportunistic fungal infections. Despite effective antiretroviral therapy (ART), opportunistic fungal infections continue to be a major cause of HIV-related mortality. Human immune responses are known to play a critical role in controlling fungal infections. However, the effect of HIV infection on innate and adaptive antifungal immunity remains unclear. Here, we review recent advances in understanding of the fungal microbiota composition and common fungal diseases in the setting of HIV. Moreover, we discuss innate and adaptive antifungal immunity in HIV infection.

HIV-infected patients rarely develop invasive fungal diseases under good immune reconstitution after ART regardless high prevalence of pathogenic filamentous fungi carriage in nasopharynx/oropharynx

PURPOSE

We aimed to investigate the prevalence and risk factors of filamentous fungi (FF) carriage in human immunodeficiency virus (HIV)-infected patients in Guangdong province, along with its subsequent incidence of invasive fungal disease (IFD).

METHODS

Seven hundred and sixteen HIV-infected individuals from the outpatient clinic and 293 sex-matched healthy controls were recruited prospectively from May 1 to August 31, 2017. Fungi were isolated from oropharyngeal and nasopharyngeal swabs, then identified by morphological and molecular biological techniques. Logistic regression analysis was used to identify risk factors of pathogenic FF carriage. Pathogenic FF carriers were followed up through the end of 2019.

RESULTS

Of the 716 included HIV-infected patients, 602 (84.1%) were male, the median age was 34 (27-42) years, and the median CD4+ count was 385 (254-542) cells/μl. Pathogenic FF were isolated in 119 (16.6%) cases with HIV infection and 40 (13.7%) healthy controls. Mucorales were found in 3 HIV-infected individuals and Talaromyces marneffei in 2 HIV-infected individuals, but not in healthy controls. History of cured opportunistic infections (OIs; OR, 1.97; 95% CI, 1.23-3.13, p = 0.004), and smoking (OR, 1.55; 95%CI, 1.03-2.32, p = 0.035) were independent risk factors of pathogenic FF carriage in HIV-infected individuals. A total of 119 pathogenic FF carriers with HIV infection were followed. During follow-up, 119 (100%) cases received antiretroviral therapy (ART) for at least 28 months, 107 (90%) cases had CD4+ counts>200 cells/μl, and none developed IFD.

DISCUSSION

Pathogenic FF carriage is common in HIV-infected individuals but may not develop IFD in those who achieved immune reconstitution. Smoking and cured OIs history increase the risk of pathogenic FF carriage. Smoking abstinence and ART adherence are especially important for these patients.

Epidemiology, prevalence, and associated factors of oral candidiasis in HIV patients from southwest Iran in post-highly active antiretroviral therapy era

Background

Oral candidiasis (OC) is one of the most common opportunistic fungal infections among people living with HIV/AIDS (PLWHA). The prevalence of OC and Candida profiles among HIV-infected patients might be changing in the era of Highly Active Antiretroviral Therapy (HAART). This study aimed to identify Candida spp., determine OC prevalence and associated risk factors for PLWHA.

Materials and methods

Oral candidiasis prevalence was explored in oral swabs of 276 patients who referred for consultation at Behavioral Diseases Counseling Center (BDCC). Clinical symptoms, culture and molecular assays were used for OC detection. In statistical analysis, we assessed socio-demographic characteristics, clinical information and treatment history of some infections.

Results

The overall prevalence of OC was 41%. Candida albicans (64.6%) was the most common species, followed by C. glabrata (26.5%) and C. dubliniensis (19.5%). Candida famata, C. africana, and C. stellatoidea as the first fungi isolated from OC in PLWHA from southwest Iran. In 36.3% of patients, mixed cultures of more than one species were observed. Body mass index (BMI) (OR = 0.947; CI = 0.89–0.99; p = 0.045) and CD4 count ≤ 200 cells/mm3 (OR = 4.365; CI = 1.73–10.98; p = 0.002) were the predictors of OC in the final model of multiple logistic regression analysis. Education level, addiction status, sexual behaviors, chest X-ray, other infections and WHO clinical stage were other important risk factors for OC.

Conclusion

Oral candidiasis remains a significant opportunistic infection in post-HAART era among PLWHA. Despite the increasing prevalence of NAC species, C. albicans (64.6%) was still the predominant species. Our results showed that low BMI with OC indicates treatment failure (i.e., failure to increase CD4 count or suppress viral load). Also, low CD4 counts (≤200 cells/mm3) in HIV patients show an impaired immune status, and our findings emphasize that OC can be a clinical indicator of HIV infection in individuals who do not know their HIV status or have failed treatment.

Transcription Factors of CAT1, EFG1, and BCR1 Are Effective in Persister Cells of Candida albicans-Associated HIV-Positive and Chemotherapy Patients

Background

Biofilm is an accumulation of cells, which are formed on mucosal surfaces of the host as well as on medical devices. The inherent resistance of Candida strains producing biofilms to antimicrobial agents is an important and key feature for biofilm growth, which can lead to treatment failure. This resistance is due to the regulatory increase of the output pumps, the presence of extracellular matrix, and the existence of persister cells. Persister cells are phenotypic variants that have MICs similar to antibiotic-sensitive populations and are able to tolerate high doses of antibiotics. The current study investigated the possible role of EFG1, BCR1, and CAT1 in the establishment or maintenance of persister cells in Candida albicans strains that produce biofilms.

Methods

After identifying Candida isolates by molecular methods, C. albicans isolates were confirmed by sequencing. Isolation of persister cells and determination of their MIC were performed by microdilution method. Then, RNA extraction and cDNA synthesis were performed from 60 C. albicans isolates under promoting and inducing conditions. Afterward, the mean expression of BCR1, EFG1, and CAT1 genes in both persister and non-persister groups was calculated using real-time qPCR. Phylogeny tree of persister and non-persister group isolates was drawn using ITS fragment.

Results

A total of 77 persister isolates were taken from the oral cavity of HIV patients as well as from patients undergoing chemotherapy. Biofilm intensity in persister isolates separated from HIV-infected patients was different from the non-persister group. The mean fold change of BCR1 (10.73), CAT1 (15.34), and EFG1 (2.41) genes in persister isolates was significantly higher than these genes in isolates without persister.

Conclusion

It can be concluded that the most important factor in the production of persister cells is biofilm binding and production, not biofilm development or mature biofilm production, which was found in the expression of BCR1 gene without change in the expression of EFG1 gene in the persister group. Also, catalase plays an essential role in the production of persister in C. albicans biofilm producers with ROS detoxification.

EFSA Panel on Biological Hazards (BIOHAZ), Koutsoumanis K, Allende A, Alvarez‐Ordóñez A, Bolton D, Bover‐Cid S, Chemaly M, Davies R, De Cesare A, Hilbert F, Lindqvist R, Nauta M, Peixe L, Ru G, Simmons M, Skandamis P, Suffredini E, Cocconcelli PS, Fernández Escámez PS, Maradona MP, Querol A, Sijtsma L, Suarez JE, Sundh I, Vlak J, Barizzone F, Hempen M, Herman L. Update of the list of QPS-recommended biological agents intentionally added to food or feed as notified to EFSA 13: suitability of taxonomic units notified to EFSA until September 2020

The qualified presumption of safety (QPS) approach was developed to provide a regularly updated generic pre-evaluation of the safety of biological agents, intended for addition to food or feed, to support the work of EFSA's Scientific Panels. It is based on an assessment of published data for each agent, with respect to its taxonomic identity, the body of knowledge, safety concerns and antimicrobial resistance. Safety concerns identified for a taxonomic unit (TU) are, where possible, confirmed at strain or product level, and reflected by 'qualifications'. In the period covered by this statement, no new information was found that would change the status of previously recommended QPS TUs. Of the 36 microorganisms notified to EFSA between April and September 2020, 33 were excluded; seven filamentous fungi (including Aureobasidium pullulans based on recent taxonomic insights), one Clostridium butyricum, one Enterococcus faecium, three Escherichia coli, one Streptomyces spp. and 20 TUs that had been previously evaluated. Three TUs were evaluated; Methylorubrum extorquens and Mycobacterium aurum for the first time and Bacillus circulans was re-assessed because an update was requested in relation to a new mandate. M. extorquens and M. aurum are not recommended for QPS status due to the lack of a body of knowledge in relation to use in the food or feed chain and M. aurum, due to uncertainty concerning its pathogenicity potential. B. circulans was recommended for QPS status with the qualifications for 'production purposes only' and 'absence of cytotoxic activity'.