Fern extracts potentiate fluconazole activity and inhibit morphological changes in Candida species

Objective: To investigate the antifungal activity of the fern species Lygodium venustum(L. venustum) and Pityrogramma calomelanos(P. calomelanos) against Candida albicans and Candida tropicalis strains.Methods: The microdilution method was used to evaluate the antifungal activity, as well as the modulating effects of ethanolic extracts of these plants in combination with fluconazole. The minimum inhibitory concentration(MIC), minimum fungicide concentration and morphological changes were also determined.Results: The extract obtained from L. venustum presented a MIC > 8 192 mg/m L, while the extract obtained from and P. calomelanos presented a MIC = 8 192 mg/m L, indicating that they present weak antifungal activity. However, combination of the extracts with Fluconazole potentiated the antifungal activity of this drug. At different experimental conditions, such as concentration of the extract and type of strain, the extracts inhibited hyphae and pseudohyphae formation, indicating that these fern species can affect the morphology of the fungi.Conclusions: The extracts obtained from the fern species L. venustum and P. calomelanos dose not present significant antifungal activity. However, P. calomelanos potentiates the activity of fluconazole and both extracts inhibits the morphological changes in Candida species, indicating that they have potential pharmacological activity as modulators of fungal biology. Therefore, novel studies are required to characterize the interference of these extracts in the virulence and pathogenicity of Candida species as well as the potential of fern species to treat fungal infections.

Characterization of oral yeasts isolated from healthy individuals attended in different Colombian dental clinics

The aim of this study was to identify the most frequent yeasts in the oral cavity of adult individuals without immune disorders and to associate the presence of these oral yeasts with different characteristics of each individual. Oral rinse samples were obtained from 96 healthy adults and cultured in Sabouraud dextrose agar media and CHROMagar. Yeasts were identified by sequencing the D1/D2 region of the 28 S rRNA gene. Probable association among the socio-demographic characteristics, body mass index, family and personal medical history,oral hygiene, tobacco and/or alcohol consumption habits and presence of oral fungi was analyzed. Contingency tables and logistic regression were employed to evaluate possible relationships between the presence of oral fungi and mixed colonization with these variables. 57.3% of the healthy individuals had oral yeasts and 21.8% had mixed colonization. The most prevalent yeasts were Candida albicans(52%), C. parapsilosis(17.9%), and C.dubliniensis(7.57%). Yeasts with most frequently mixed colonization were C. albicans and C. parapsilosis. No relationships were found among the variables analyzed. However, the presence of mixed colonization was related to the presence of dental prostheses(P<0.006), dental apparatuses(P=0.016) and O’Leary index(P=0.012). This is the first study that characterized oral yeasts in Colombian healthy individuals, determined the most prevalent oral yeasts C. albicans, C. parapsilosis and C. dublinensis and an association of mixed colonization with the use of dental prostheses and aparatology and poor hygiene.

Isolation and Characterization of Hydrocarbon Utilizing Yeast (HUY) Isolates from Palm Wine

Several studies have reported on the capabilities of different yeasts to utilize hydrocarbons hence the need to ascertain the petroleum hydrocarbon biodegradation potential of yeast isolated from palm wine. The study aimed at isolation, characterization and testing of yeasts from palm wine for biodegradation of petroleum hydrocarbons. Hydrocarbon utilizing yeasts (HUY) were isolated from palm wine, a rich sugar substrate from a non-oil impacted environment using Bacto Bushnell Haas broth. The medium composed of 0.2 g MgSO4, 0.02 g CaCl2, 1 g KH2PO4, 1 g K2HPO4, 0.05 g FeCl2, 1 g/L NH4NO3, pH (7.2 ± 0.2) and mineral salt broth comprising of 4.4 g KH2PO4, 8 g (NH4)2SO4, 2 g Na2HPO4·H2O, MgSO4ܭH2O, 0.1 g FeSO4, 0.01 g/L CaCl2, pH (4.5 ± 0.2) supplemented with palm wine (0.5%) and crude oil (1%). Yeasts isolated from an enriched medium and palm wine showed similarities. Yeast isolates were further screened for hydrocarbon degrading potentials using the Bacto Bushnell Haas broth containing 2, 6-dichlorophenol indophenols as the indicator agent. The isolates were identified using microscopic, macroscopic, fermentation and molecular characteristics as Candida adriatica (ZIM 2468) and Candida taoyuanica (MYA-4700).

Positive sputum culture of Candida spp.as a risk factor for 30-day mortality in patients with hospital-acquired pneumonia:A propensity-score matched retrospective clinical study

Background:Candida species(Candida spp.)are commonly isolated microorganisms from lower respiratory tract(LRT)specimens of patients with hospital-acquired pneumonia(HAP);however,the clinical significance remains controversial.This study aimed to investigate the correlation between Candida spp.in the LRT and the clinical features and prognosis of HAP.Methods:This retrospective analysis included eligible patients with HAP from the database of a prospective study carried out between 2018 and 2019 in nine Chinese hospitals.Data on demographics,clinical characteristics,and prognosis were collected and analyzed.Propensity score matching(PSM)was used to balance the baseline characteristics.Results:A total of 187 HAP patients were enrolled.After PSM of severity score,27 cases with positive sputum culture of Candida spp.were compared with the control group at a ratio of 1:1.The Candida-positive group had more bacterial isolates in blood culture than the Candida-negative group(39.1%[9/23]vs.7.7%[2/26],χ^(2)=6.928,effect size[ES]=0.38,95%CI:0.12-0.61,P=0.008).The proportion of patients with chronic lung diseases was significantly higher in the Candida-positive group(55.6%[15/27]vs.22.2%[6/27],χ^(2)=6.312,ES=0.34,95%CI:0.07-0.59,P=0.012).The 30-day prognosis of HAP was significantly different between the two groups(80.8%[21/26]vs.38.5%[10/26],χ^(2)=9.665,ES=0.43,95%CI:0.19-0.66,P=0.002).Univariable logistic regression analysis showed that LRT Candida spp.colonization was a risk factor for 30-day mortality of HAP(OR=6.720,95%CI:1.915-23.577,P=0.003).Conclusions:Candida spp.in the LRT was associated with 30-day mortality of HAP.Patients with chronic under-lying lung diseases tend to have Candida spp.colonization.

Etiology of invasive candidosis agents in Russia： a multicenter epidemiological survey

A multicenter prospective epidemiological survey on the etiologic agents of invasive candidosis was conducted in Russia in the period of 2012-2014. Samples were collected from 284 patients with invasive candidosis and Candida species isolated by culture. The species were identified by DNA sequencing and MALDI-TOF mass- spectrometry. A total of 322 isolates were recovered, in which 96% of Candida species belonged to six major species, namely, C. albicans （43.2%）, C. parapsilosis （20.2%）, C. glabrata （11.5%）, C. tropicalis （9.6%）, C. krusei （6.2%）, and C. guilliermondii （5.3%）. Most Candida species were isolated from blood samples （83.23%）. Notably, the prevalence rate of C. albicans reduced from 52.38% to 32.79% （2012 vs. 2014） （P = 0.01） whereas that of non-C. albicans increased from 47.62% （2012） to 67.21% （2014） （P〈 0.01）. Species distribution differed among geographical regions; specifically, the prevalence rate of C. albicans as an etiologic agent of invasive candidosis in Siberian Federal region was significantly higher than that in other Federal regions. Results indicated a shift from C. albicans to non-C, albicans. Therefore, a detailed investigation on the contributing factors and appropriate treatment of invasive candidosis is needed.