ABSTRACT: Background: Drug resistance among Candida species constitutes the most significant problem in the treatment of Candidiasis.Systematic studies on antifungal drug susceptibility which may be useful in deciding clinical strategies are not routinely done in India and other developing countries. Objective: Aim of this study was testing sensitivity of clinical isolates of Candida albicans and non albicans to frequently prescribe antifungal drugs, fluconazole, ketoconazole, Itraconazole, Amphotericin B and Terbinafine. Material and methods: 25 strains of C. albicans and non albicans were tested in vitro for susceptibility to five antifungal agents, by using standard broth macro dilution method (CLSI M 27-A). Results: The present study revealed the percentage and extent of emerging drug resistance and cross resistance among Central Indian clinical isolates of C. albicans and non albicans against azoles and allylamine. In the present study, the total percentage of resistance was found to be 84% (21/25). The drug for which maximum resistance were found was Ketoconazole (64%) followed by Itraconazole (44%) Terbinafine (24%) and lastly Fluconazole (20%). The total percentage of cross resistance was 62% (13/21) and the maximum seen in C. albicans followed by C. glabrata, C. krusei and C. guilliermondi. No resistance was found for polyene drug Amphotericin B. Conclusion: This short study from India has exhibited the increasing frequency of resistance and Cross resistance of C.andida species against azoles and allylamine. We suggest a comprehensive study to determine the extent and degree of antifungal drug resistance among Candida species in India.
Patients with candidemia usually present an acute septic syndrome that is indistinguishable from bacteremia, but they may also exhibit a more indolent course manifested by fever of unknown origin. Major risk factors for candi- demia include intravascular catheters, parenteral hyperal- imentation, and broad-spectrum antibiotics. Empirical antifungal agents may be administrated to patients mani- fested with fever of unknown origin and have above men- tioned risk factors, particularly those who have been treated with broad-spectrum antibiotics. The clinical pres- entation of the patients with sepsis caused by C. albicans and NAC are indistinguishable. However, NAC are often less susceptible to fluconazole than C. albicans is [7,11,12] and may require greater dosage to cure clinically [13,14]. We have conducted a retrospective chart review of patients whose death was associated with candidemia. The goal was to assist decisions to select the most appropriate empirical therapy for patients suspected to have candi- demia. The objective was to determine whether specific risk factors could be identified to help selecting those patients who are more likely infected with C. albicans ver- sus NAC.
Other evidence also suggests that NAC infections war- rant significant concern. Several reports note that NAC species appear to be associated with severe or recurrent cases of VVC [10,13]. Zeng et al. notes that a greater percentage of NAC infections than C. albicans infections is associated with more severe symptoms . Simi- larly, Girgoriou et al. reports that NAC caused more fre- quent vaginal soreness and dyspareunia than C. albicans . The predominant NAC species cited in these studies, C. glabrata, as well as other strains including C. krusei, do not reliably respond to azoles [4,16,20,21]. Therefore, identification is needed to better direct therapy.
ABSTRACT: Candidemia is associated with a high mortality. The most common cause of candidemia is Candida albicans, though infections by non- albicans Candida are being increasingly reported. The present study was conducted to determine the incidence of candidemia, the risk factors and antifungal susceptibility in intensive care unit (ICU). This study was conducted from January 2012 to June 2013 and prospectively included patients admitted in ICU for >48 hours. The blood culture isolates were identified as per standard mycological procedures and DNA (26S rDNA) sequencing. Antifungal susceptibility test was carried out by broth micro- dilution method in accordance with CLSI standards. A total of 48 isolates were identified in 1890 ICU admissions. Majority of the isolates were identified as non-albicans Candida i.e. 38 out of 48 isolates which is 79.2% while only 10 isolates were that of Candida albicans i.e. 20.8%. Among the non albicans species, Candida tropicalis (42.1%) was the predominant one followed by Candida rugosa (26.3%), Candida parapsilosis (15.8%) while Candida pelliculosa, Candida glabrata, Candida lusitaniae and Kodamea ohmeri were identified from one case each i.e. 2.6% and two were Candida auris (5.3%). The association of central venous catheter with non-albicans Candida species was found to be statistically significant (P = 0.01). There was significant resistance among Candida auris and Candida rugosa isolates to commonly used antifungals hence it is important to diagnose the infection during its early course for a good outcome.
EOs have long been used in ethnomedicine as effective and safe antifungal agents; however, good scientific and clinical data that either supports or contravenes the ef- fectiveness of these alternative therapies are still needed before consumers can be sure they will enjoy any bene- fits. Previously we have studied the antimicrobial activity of thyme red, clove, pine, sage, lemon balm, fennel, lav- ender EOs against filamentous fungi . Hence, the ob- jective of this study was to extend the research to evaluate the activity of the same EOs on Candida albi- cans and non-albicans Candida strains, as well as the effects of related EO components, by using two investi- gative tools, such as the broth microdilution method (BM) and the vapour contact assay (VC). EOs selection was based both on ethnomedicinal use and on proved antibacterial and/or antifungal activity of some of these oils [8, 9]. Fluconazole and voriconazole were used as reference drugs to compare EOs activity.
is not possible, so we used effective molecular tests (duplex and multiplex-PCR) for distinguishing them. All strains in C. glabrata complex were C. glabrata, however, one C. dubliniensis and one C. orthopsilosis were isolated from C. albicans complex and C. parapsilosis complex, respectively. Candida orthopsilosis is a rare Candida spe- cies that reported by Tavanti et al.  for the first time. We also identified this species for the first time in Iran in our previous study . In agreement with our previous report, here it was isolated from a patient with fingernail infection. Trichosporon asahii (Trichosporon beigelii) was another uncommon yeast isolated in the present study and identified by PCR-sequencing. This species is con- nected with a wide spectrum of clinical signs, ranging from superficial lesions in immunocompetent individuals to severe systemic and fatal infections in immunocom- promised patients . It is the most prevalent non- Candida cause of fungemia , however, all T. asahii in the present study were isolated from urine samples. We also isolated Pichia terricola from clinical sample for the first time. Pichia genus is found in plants, fruit juices, and soil. It has also been described as a normal flora of throat, skin, and alimentary tract. Some species such as P. anomala can cause serious infections among immuno- suppressed patients mainly in infants , however, we isolated P. terricola from the urine sample of a pregnant female with severe urinary tract infection.
Three cost-effectiveness studies from other countries compared anidulafungin with fluconazole for IC, provid- ing findings that are consistent with our study. Neoh et al.’s study based on an Australian hospital perspective and Reboli et al.’s trial data  indicated that, as com- pared to fluconazole, anidulafungin was associated with an ICER of AU$25,740 per LY gained, which was under the Australian ICER threshold, suggesting that anidula- fungin is a cost-effective agent . Our additional ana- lyses, which applied Reboli et al.’s trial data , showed consistent results (Additional file 1: Table S3) with those in Neoh et al.’s study . Grau et al.’s study from Spain showed that anidulafungin was cost-saving over flucona- zole, with a higher clinical success (74% vs. 57%) at a lower total medical cost (€40,047 vs. €41,350) and that the clinical efficacy of antifungal treatment was the most influential factor in the cost-effectiveness analysis , which is consistent with the results of the sensitivity analyses in the present study (Fig. 2). Auzinger et al.’s study, from the perspective of the United Kingdom National Health Service and Personal and Social Services, showed that anidulafungin was cost-effective as compared to fluconazole (ICER: £813 per LY gained) and cost-saving versus caspofungin and micafungin . However, none of these studies analyzed the cost-effectiveness of antifun- gal treatments for specific species (i.e., C. albicans).
with candidemia due to C. albicans and 67 patients with candidemia due to non-albicans Candida species . Previous exposition to azole agents, duration of central venous catheter implantation and the number of antimi- crobial agents per day were associated with non-albicans Candida infection in multivariate analyses. Conversely, the duration of parenteral nutrition was associated with a reduced risk of non-albicans Candida infection. Finally, 189 candidemic patients (C. albicans: 56%) were included in the international, multicenter, retrospective study of Holley et al. . Factors associated independently with candidemia due to non-albicans Candida species were female gender and duration of central venous catheter implantation using multivariate analysis.
Found in many fermented foods and beverages, yeasts are an inevitable part of the daily diet of humans in most cultures. Yeast-based probiotics are especially desirable because they are naturally resistant to most antibiotics, which allows them to persist in the gastrointestinal (GI) tract during an antibiotic regimen when the bacterial micro- ﬂora may be compromised. The use of Saccharomyces cerevisiae is particularly attractive for probiotic applications and is generally regarded as safe (GRAS) by the U.S. Food and Drug Administration (FDA) (18). Recently published preclinical and clinical studies support the use of probiotics against C. albicans (19), and Saccharomyces boulardii is already commercially available. A probiotic cocktail of yeast and bacteria in combina- tion with prebiotics was found to reduce colonization of C. albicans in preteen children (20). Additionally, recent evidence suggests that vaginal administration of S. cerevisiae in mice signiﬁcantly reduced C. albicans colonization during vulvovaginal candidiasis (VVC) (21). However, there is limited knowledge about the effects of probiotic yeasts on non-albicans Candida strains. Here, we tested the effects of two novel probiotic yeasts, Saccharomyces cerevisiae (strain KTP) and Issatchenkia occidentalis (strain ApC), that were derived from food sources (22). Here, we used multiple readouts, including in vitro and ex vivo assays and analyses of morphological transition and bioﬁlm formation of four non-albicans Candida strains, C. tropicalis, C. krusei, C. glabrata, and C. parapsilosis, to demonstrate the efﬁcacy of probiotic yeast application. We also used Caenorhabditis elegans as a whole-animal infection model to study the effects of exposure to probiotic yeasts. Finally, we demonstrate that the use of probiotic yeasts represents an effective method to control the multidrug-resistant species Candida auris.
13 Read more
problems. Recent literatures have reported the isolation of Candida from the hands of health care workers in intensive care units and cross- infection. Epidemiologic studies showed that Candida non albicans are more frequently isolated from the urine samples than the other clinical samples, this may be probably due to urine composition and or pH. Mixed isolates were found in patients with nosocomial Candiduria. The emergence of Candida non albicans species may represent selection of more resistant species like C. glabrata and C.krusei 33 .
163 Read more
C. albicans and bacteria can coexist within the host (17–19), where the nature of the interspecies interactions can determine the fate of the microbial populations (20) and thus probably the outcome of polymicrobial diseases. C. albicans and Pseudomonas aeruginosa, two species commonly found together in mixed- species, biofilm-related infections (21), interact in many different ways through physical association, killing by secreted factors and signaling events that modulate virulence properties (22–29). P. aeruginosa adheres to and forms biofilms on C. albicans fila- ments (23) and ultimately causes the death of the fungal hypha. A P. aeruginosa quorum-sensing molecule also induces a transition to yeast growth, and yeasts are more resistant to killing by P. aeruginosa (23). Redox-active phenazines produced by P. aeruginosa play a key role in controlling C. albicans when the two species are in close proximity (24, 29). We reported that C. al- bicans growth was antagonized by two P. aeruginosa phenazines, pyocyanin (PYO) and its biosynthetic precursor 5-methyl- phenazinium-1-carboxylate (5MPCA), as well as by a synthetic methylphenazinium analog phenazine methosulfate (PMS), which we have shown to be a surrogate for studying 5MPCA’s antifungal activity (24, 29) (see Fig. S1 in the supplemental mate- rial for chemical structures). Phenazines play important roles in bacterial interactions with fungi in which high concentrations of phenazines inhibit fungal growth (30).
ABSTRACT Biofilm-associated polymicrobial infections, particularly those involving fungi and bacteria, are responsible for sig- nificant morbidity and mortality and tend to be challenging to treat. Candida albicans and Staphylococcus aureus specifically are considered leading opportunistic fungal and bacterial pathogens, respectively, mainly due to their ability to form biofilms on catheters and indwelling medical devices. However, the impact of mixed-species biofilm growth on therapy remains largely un- derstudied. In this study, we investigated the influence of C. albicans secreted cell wall polysaccharides on the response of S. au- reus to antibacterial agents in biofilm. Results demonstrated significantly enhanced tolerance for S. aureus to drugs in the pres- ence of C. albicans or its secreted cell wall polysaccharide material. Fluorescence confocal time-lapse microscopy revealed impairment of drug diffusion through the mixed biofilm matrix. Using C. albicans mutant strains with modulated cell wall poly- saccharide expression, exogenous supplementation, and enzymatic degradation, the C. albicans-secreted ␤ -1,3-glucan cell wall component was identified as the key matrix constituent providing the bacteria with enhanced drug tolerance. Further, antibody labeling demonstrated rapid coating of the bacteria by the C. albicans matrix material. Importantly, via its effect on the fungal biofilm matrix, the antifungal caspofungin sensitized the bacteria to the drugs. Understanding such symbiotic interactions with clinical relevance between microbial species in biofilms will greatly aid in overcoming the limitations of current therapies and in defining potential new targets for treating polymicrobial infections.
12 Read more
C. albicans stimulation of C2BBe1 cells induces a transient CEACAM1 tyrosine phosphorylation. Although we did not ﬁnd any consequences of CEACAM molecule FIG 4 CEACAM1 becomes phosphorylated by C. albicans but does not affect yeast cell adhesion to epithelial monolayers. (A) HeLa cells stably transfected with empty vector, human CEACAM1-4L (CC1), a human CEACAM1-4L deletion mutant lacking the N-terminal IgV-like domain (CC1dN), or human CEACAM6 (CC6) were incubated with C. albicans yeast cells for 60 min. Shown are mean adhered cells as a percentage of input from three individual experiments done in triplicate. (B) For adhesion assays, C2BBe1 cells were carefully washed to remove mucus from the cell monolayer. C. albicans yeast cells were preincubated with cell culture supernatants conditioned by C2BBe1 cells left untreated (C2) or treated with UV-inactivated C. albicans yeast cells for 72 h (C2/Ca) and were allowed to adhere to C2BBe1 cells for 30 min in the presence of the respective preconditioned media. Shown are mean adhered cells as a percentage of input from three individual experiments performed in triplicate. (C and D) To analyze the tyrosine phosphorylation of CEACAM1, C2BBe1 cells were incubated with C. albicans SC5314 yeast cells for the indicated times (n ⫽ 4). Cells were lysed, CEACAM1 was immunoprecipitated, and samples were analyzed by Western blotting for phosphotyrosine and subsequently for CEACAM1 (C). Note that both CEACAM1-4L (upper p-Tyr band) and CEACAM-3L (lower p-Tyr band) isoforms become phosphor- ylated. (D) Phosphotyrosine signals were quantiﬁed: the fold changes after C. albicans treatment compared to untreated cells (100%) are shown in the graph. (E) C2BBe1 cells were incubated with C. albicans germ tubes and analyzed as described for panel C. Statistical analysis was performed with the two-sided paired t test for panels A and B and the two-sided unpaired t test for panel D. Bars in all graphs depict the mean (wide bars) ⫾ SD (narrow bars, if applicable). ns, not signiﬁcant.
16 Read more
Oral infection assays. Oral infections were carried out essentially as described previously (27). C. albicans strains were grown overnight at 30°C in YPD medium with 80 g/ml uridine, reinoculated into fresh medium, and incubated again overnight at 30°C. Cells were harvested by centrifugation, washed twice in phosphate-buffered saline (PBS), counted in a hemocytometer, and then diluted to the appropriate density with PBS. To test the effects of preinduction of hyphae, cells were pregrown in YPD containing 10% bovine serum for 90 min at 37°C. C57BL/6 mice were injected 1 day before infection with cortisone acetate (catalog number C3130; Sigma-Aldrich) to induce immunosuppression. Cortisone acetate was dissolved in PBS with 0.05% (vol/vol) Tween 80 and administered at 225 mg/kg mouse in 0.2 ml. The mice were subsequently injected with additional doses of cortisone acetate 1 and 3 days after infection. Mice were sedated with 0.2 ml of ketamine (100 mg/kg of body weight) and xylazine (10 mg/ kg). A calcium alginate swab (Puritan Medical Products Co., Guilford, ME) saturated with a suspension of 10 6 C. albicans cells/ml was then placed under the tongue for 75 min. Mice were then monitored for
14 Read more
ABSTRACT The phagocytic cells of the innate immune system are an essential ﬁrst line of antimicrobial defense, and yet Candida albicans, one of the most prob- lematic fungal pathogens, is capable of resisting the stresses imposed by the macrophage phagosome, eventually resulting in the destruction of the phago- cyte. C. albicans rapidly adapts to the phagosome by upregulating multiple alter- native carbon utilization pathways, particularly those for amino acids, carboxylic acids, and N-acetylglucosamine (GlcNAc). Here, we report that C. albicans recognizes these carbon sources both as crucial nutrients and as independent signals in its en- vironment. Even in the presence of glucose, each carbon source promotes increased resistance to a unique proﬁle of stressors; lactate promotes increased resistance to osmotic and cell wall stresses, amino acids increased resistance to oxidative and ni- trosative stresses, and GlcNAc increased resistance to oxidative stress and caspofun- gin, while all three alternative carbon sources have been shown to induce resistance to ﬂuconazole. Moreover, we show mutants incapable of utilizing these carbon sources, in particular, strains engineered to be defective in all three pathways, are signiﬁcantly attenuated in both macrophage and mouse models, with additive ef- fects observed as multiple carbon pathways are eliminated, suggesting that C. albi- cans simultaneously utilizes multiple carbon sources within the macrophage phago- some and during disseminated candidiasis. Taking the data together, we propose that, in addition to providing energy to the pathogen within host environments, al- ternative carbon sources serve as niche-speciﬁc priming signals that allow C. albicans to recognize microenvironments within the host and to prepare for stresses associ- ated with that niche, thus promoting host adaptation and virulence.
18 Read more
of SpeB were correlated with increase dispersal. Indeed, srv mu- tant strains were observed to form larger lesions than wild-type strains in a murine subcutaneous infection model (39, 40). In enteropathogenic Escherichia coli, deletion of BfpF, which is re- quired for the production of type IV bundle-forming pili that are necessary for biofilm dispersal, reduced virulence by about 200- fold relative to that of the wild type in a model measuring postin- oculation dose-dependent diarrheal response in human volun- teers (41). There is also some evidence in support of this hypothesis linking dispersal and disease progression in fungal bio- films. For example, genetic evidence in C. albicans suggests that deletion of Nrg1, a known dispersal regulator (20), completely attenuates virulence in a murine model of disseminated candidi- asis (42). However, deletion of Nrg1 has profound effects on the morphology of planktonic cells, so it is not possible to ascribe its effects solely to biofilm dispersal. Finally, it was shown that cells dispersed from wild-type biofilms have greater virulence than standard wild-type planktonic cells in a murine disseminated in- fection model (15).
13 Read more
IMPORTANCE Sexual reproduction is an important mechanism in the evolution of species, since it allows the combination of advantageous traits of individual mem- bers in a population. The pathogenic yeast Candida albicans is a diploid organism that normally propagates in a clonal fashion, because heterozygosity at the mating type locus (MTL) inhibits mating between cells. Here we show that C. albicans cells that have acquired drug resistance mutations during treatment with the commonly used antifungal agent ﬂuconazole rapidly develop further increased resistance by genome rearrangements that result in simultaneous loss of heterozygosity for the mutated allele and the mating type locus. This enables the drug-resistant cells of a population to switch to the mating-competent opaque morphology and mate with each other to combine different individually acquired resistance mechanisms. The tetraploid mating products reassort their merged genomes and, under selective pressure by the drug, generate highly resistant progeny that have retained the ad- vantageous mutated alleles. Parasexual propagation, promoted by stress-induced ge- nome rearrangements that result in the acquisition of mating competence in cells with adaptive mutations, may therefore be an important mechanism in the evolu- tion of C. albicans populations.
21 Read more
Chitin is remasked by an unidentiﬁed, secreted, small heat-stable compound. As farnesol had no impact of chitin remasking, we sought to identify the secreted molecule regulating chitin exposure. To determine whether the secreted factor was a protein or nucleotide, the supernatants were heat inactivated and treated with protei- nase K, DNase, or RNase. However, supernatants devoid of secreted proteins and nucleotides still inhibited chitin exposure under acidic conditions, although pH 4 samples always had slightly more chitin exposure than pH 6 samples (Fig. S4A), suggesting that the secreted factor is a heat stable, nonproteinaceous secreted fac- tor(s). To elucidate the hydrophobicity of the secreted molecule, hydrophobic mole- cules were removed from the supernatants using Amberlite. Supernatants containing only hydrophilic molecules still induced chitin remasking (Fig. S4A). To identify the size of the secreted molecule(s), the supernatants were size fractionated. Due to the size exclusion columns removing nutrients from the medium, ﬁltered supernatants were diluted 1:1 with fresh buffered medium. Diluted supernatants maintained a modest effect on chitin exposure, which was maintained in fractions containing molecules smaller than 3 kDa, although pH 4 samples always had slightly more chitin exposure than pH 6 samples. On the other hand, supernatants containing only molecules larger than 3 kDa showed greater chitin exposure at pH 4 (Fig. S4B). Taken together, the data suggest that a secreted, small, heat-stable non-proteinaceous molecule(s) regulates chitin exposure in response to pH, although other factors may also play a role. Therefore, multiple processes regulate cell wall remasking, with chitin remasking induced by the secretion of an unidentiﬁed secreted, small, heat-stable, non-proteinaceous hydrophilic molecule and glucan exposure regulated by farnesol in a cell density- dependent manner.
19 Read more
To determine the effects of mnt1⌬ mnt2⌬ mutation on the production of hyphal cell wall proteins, we prepared cell walls from hypha-forming cells and subjected them to trypsin digestion and proteome analyses. In C. albicans cell walls, the more abun- dant covalently attached proteins are GPI modified, whereas the least abundant are attached via an alkali-labile linkage (66). Our experiments identified peptides from proteins present in the cell wall through covalent linkage. Proteins missing from the cell wall extracts would be either not expressed (transcription) or not properly incorporated (covalently linked) into the cell wall or lacking amenable trypsin cleavage sites. In the mnt1⌬ mnt2⌬ mu- tant grown in YPT-Glc, there were significant reductions in a wide range of CWPs that would be expected to have major effects on phenotypes such as adhesion, biofilm formation, and invasion of host cells (9, 50, 51). In the presence of GlcNAc, however, the mnt1 ⌬ mnt2 ⌬ mutant showed a cell wall proteome much more similar to that of the wild type. Peptides from the GPI-modified hypha-specific adhesin Hwp1 were not detected by liquid chromatography-tandem mass spectrometry (LC-MS/MS), as also reported by others (67). During hypha formation there is enrichment of carbohydrate-active or cell wall-remodeling en- zymes Cht2, Crh11, Mp65, Pga4, Phr1, Phr2, and Utr2 (49, 67). We have identified six of these proteins in our studies. Actual relative amounts will be dependent upon the methods employed in cell wall purification and MS analysis and most importantly the precise conditions utilized for growth and hypha formation.
15 Read more
Results: A total of 197 (65.6%) out of 300 non-repetitive swabs had positive growth of Candida spp. Candida albicans 125 (63.4%) was the most predominant isolated specie followed by C. tropicalis 35 (17.8%) and C. glabrata 33 (16.8%). Laboratory confirmed candida vaginitis was independently predicted by douching practices (OR 3.2, 95% CI 1.3–7.5 P = 0.007), history of antibiotics use (OR 1.8, 95% CI 1.02–3.0, P = 0.04) and low social economic status (OR 2.04, 95% CI 1.1–3.7 P = 0.02). About two-third of pregnant women with clinical features of vaginitis attending antenatal clinic in Mwanza, Tanzania were confirmed to have Candida vaginitis mainly caused by Candida albicans.