Antifungal Resistance Profile, Biofilm Formation, and Virulence Factor Production in Candida krusei Isolates From HIV-Infected Patients in Cameroon.

Background Fungal infections mainly caused by Candida krusei are increasing rapidly and represent a serious public health problem in human immunodeficiency virus (HIV)-infected patients. This study aimed to investigate the antifungal susceptibility profile and virulence factors in C. krusei isolated from HIV-infected patients. Methodology Isolates were identified by biochemical and molecular methods. The antifungal resistance profile was established based on the antifungal susceptibility test performed using the Sensititre YeastOne™ (Thermo Fisher Scientific, Waltham, MA) microdilution technique. The production of phospholipase and proteinase was detected by standard methods. Biofilm formation was performed by the microtiter plate method. Results A total of 73 isolates of C. krusei were recovered from stool, oral swabs, vaginal swabs, and urine samples. The highest number of C. krusei isolates (49, 67.05%)was recovered from stool samples. A total of 32.56% of the C. krusei isolates were multidrug-resistant (MDR). The patients living with HIV and not receiving antiretroviral treatment displayed the highest number of C. krusei isolates (29, 39.76%), whereas the patients living with HIV on antiretroviral therapy exhibited the lowest number of C. krusei isolates (2, 2.72%). All isolates were categorized as strong biofilm producers. Among the production of hydrolytic enzymes, 25 (58.13%) and 24 (55.81%) of C. krusei isolates were classified as strong phospholipase and proteinase producers, respectively. Conclusion The C. krusei isolates obtained in this study were MDR and strongly expressed biofilm formation and both phospholipase and proteinase hydrolytic enzymes. The results show how pathogenic C. krusei is in the HIV-infected population and will contribute toward the management of C. krusei-related infections, which may help improve the life quality of people living with HIV.

Multilocus sequence typing (MLST) analysis reveals many novel genotypes and a high level of genetic diversity in Candida tropicalis isolates from Italy and Africa.

BACKGROUND: Candida tropicalis is a human pathogenic yeast frequently isolated in Latin America and Asian-Pacific regions, although recent studies showed that it is also becoming increasingly widespread throughout several African and south-European countries. Nevertheless, relatively little is known about its global patterns of genetic variation as most of existing multilocus sequence typing (MLST) data come from Asia and there are no genotyped African isolates. OBJECTIVES: We report detailed genotyping data from a large set of C. tropicalis isolates recovered from different clinical sources in Italy, Egypt and Cameroon in order to expand the allele/genotype library of MLST database (https://pubmlst.org/ctropicalis), and to explore the genetic diversity in this species. METHODS: A total of 103 C. tropicalis isolates were genotyped using the MLST scheme developed for this species. All isolates were also tested for in vitro susceptibility to various antifungals to assess whether certain genotypes were associated with drug-resistance. RESULTS AND CONCLUSIONS: A total of 104 different alleles were detected across the MLST-loci investigated. The allelic diversity found at these loci resulted in 51 unique MLST genotypes of which 36 (70.6%) were novel. Global optimal eBURST analysis identified 18 clonal complexes (CCs) and confirm the existence of a specific Italian-cluster (CC36). Three CCs were also statistically associated with fluconazole resistance, which was elevated in Cameroon and Egypt. Our data show high genetic diversity in our isolates suggesting that the global population structure of C. tropicalis is still poorly understood. Moreover, its clinical impact in Italy, Egypt and Cameroon appears to be relevant and should be carefully considered.

In Vitro Antifungal Susceptibility of Environmental Isolates of Cryptococcus spp. from the West Region of Cameroon.

BACKGROUND: Cryptococcus neoformans is responsible of cryptococcosis, a life-threatening infection that affects healthy and immunocompromised individuals. It is the first cause of adult acute meningitis in some sub-Saharan African countries with a mortality rate of about 100% in cases of inappropriate therapy. This study aimed at examining the occurrence and the antifungal patterns of Cryptococcus isolates from pigeon droppings and bat guanos in the west region of Cameroon. METHODS: A total of 350 samples were randomly collected from three selected localities of west region of Cameroon. The identification was performed based on capsule production assessed by Indian ink preparation. Additional tests performed were urea broth, glycine and tryptophan assimilation tests. The antifungal susceptibility test was performed by the broth microdilution method. RESULTS: Mycological analysis led to the identification of 98 isolates, of which 57 isolates of C. neoformans var. gattii and 41 isolates of C. neoformans var. neoformans. All the isolates showed resistance to antifungals tested except nystatin which showed MIC mean values ranging between 0.5 µg/mL and 0.65 µg/mL. CONCLUSION: The prevalence of C. neoformans in pigeons and bats excreta in the west region of Cameroon is 28.57 %. C. neoformans var. gattii and C. neoformans var. neoformans are the main serotypes. Isolates found to be resistant to fluconazole and ketoconazole. Our results emphasize the need for further study on the molecular epidemiology in comparison with clinical isolates.