Mixed yeast infections in Taiwan.

Clinically significant yeast isolates were collected via Taiwan Surveillance of Antimicrobial Resistance of Yeasts (TSARY) in 2014, and mixed infections were investigated. Among 44 out of 1092 specimens containing multiple species, 17, 11, 5, 3, and 8 were from urine, sputum, blood, ascites, and 6 others, respectively. There predominant combinations of mixed infection were 14 Candida albicans/Candida glabrata, 13 C. albicans/Candida tropicalis, and 9 C. glabrata/C. tropicalis. Furthermore, we also detected fluconazole resistant isolates Candida norvegensis and Candida krusei. Hence, it is important to accurately identify the species with different drug susceptibilities when they are in the same specimen.

Prevalence of and risk factors for methicillin-resistant Staphylococcus aureus colonization among human immunodeficient virus-infected outpatients in Taiwan: oral Candida colonization as a comparator.

Human immuodeficency virus (HIV)-infected patients receiving highly active antiretroviral therapy (HAART) and community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) have increased in recent years in Taiwan. This study was undertaken to determine the prevalence of and risk factors for nasal and oral S. aureus and MRSA colonization among contemporary HIV-infected populations. Clinical variables for S. aureus and MRSA colonization among HIV-infected outpatients from three hospitals were analyzed and compared with those for oral Candida colonization. Genetic characteristics of MRSA isolates were analyzed. A total of 714 patients were screened for nasal S. aureus colonization, and a subset of 457 patients were also screened for oral S. aureus colonization. Of all patients, 79.4% were receiving HAART, and their mean CD4 count was 472 cells/mm3. The colonization rates in the oral cavity, nasal cavity, and at either site were 18.8%, 31.7%, and 36.8%, respectively, for S. aureus, and 3.1%, 4.4%, and 5.5%, respectively, for MRSA. These rates were all much lower than the previously reported rate of oral Candida colonization (52.4%). By multivariate analysis, a suppressed viral load (<200 copies/mL) protected against oral S. aureus, MRSA, and Candida colonization, and recent use of antibacterial agents protected against oral and nasal S. aureus colonization. Recent incarceration increased the risk of nasal MRSA colonization, while recent hospitalization, tuberculosis, older age, and intravenous drug use increased the risk of oral Candida colonization. Candida spp. did not augment S. aureus or MRSA colonization in the oral cavity. Most of the 41 MRSA isolates recovered belonged to the SCCmec IV/pvl-negative (51.2%) and VT/pvl-positive (26.8%) ST59 local prevalent CA-MRSA clones. Distinct carriage rates demonstrated here suggested that mucosal immunity against colonization might differ in terms of microbes and sites. A decreased risk in oral carriage of MRSA and Candida might be a benefit of HAART.

Fruits as the vehicle of drug resistant pathogenic yeasts.

OBJECTIVE: We investigated the diversity and drug susceptibility of pathogenic yeasts on fruit surfaces. METHOD: Fruits were purchased from supermarkets and washed with buffer. The pellets were re-suspended in medium after centrifugation. The cell suspensions were plated onto CHROMagar Candida medium. Yeasts were identified by ribosomal DNA sequencing and their drug susceptibilities were determined by broth microdilution assay. RESULTS: Of 184 isolates, comprised of 55 species, from 22 different types of fruits, 29 species, including Candida famata, Candida fermentati, Candida guilliermondii, Candida intermedia, Candida krusei, Candida orthopsilosis, Candida parapsilosis, Candida pelliculosa, Candida tropicalis, and others have been reported to cause diseases in humans. In addition to C. krusei, intrinsically resistant to fluconazole, all Rhodotorula and Rhodosporidium species were resistant to fluconazole. One each of C. tropicalis isolate was belonged to diploid sequence type (DST)149 and DST225, genotypes also detected in isolates from humans. Furthermore, the DST225 isolate was less susceptible to azole drugs. The susceptibilities to azole drugs for clinical and agricultural usage were associated to each other. CONCLUSION: It is important to be aware of the existence of pathogenic yeasts, especially drug-resistant ones, on the fruit surfaces, a potential route for pathogenic yeasts to be transmitted to humans.

The distribution and drug susceptibilities of clinical Candida species in TSARY 2014.

The species distribution and drug susceptibilities of 1106 Candida isolates collected in Taiwan Surveillance of Antimicrobial Resistance of Yeasts (TSARY) in 2014 were determined. Candida albicans is still the dominant species, accounting for 35.9%, followed by 28.3% C. glabrata, 26.6% C. tropicalis, 5.2% C. parapsilosis, 1.0% C. krusei, and 3.0% of 13 other species. Interestingly, the prevalence of candidemia caused by C. glabrata in the present study is significantly higher than that in previous three surveys (39/220 vs. 54/471, P=0.025). We found that 31 (2.8%), 24 (2.2%), 1 (0.09%), and 0 isolates were resistant to fluconazole, voriconazole, anidulafungin, and amphotericin B, respectively. There is a significant increase in fluconazole (P=0.00002) and voriconazole (P=0.00006) resistant rates when compared to the isolates collected in 2010. Importantly, all the 24 voriconazole resistant isolates identified were also resistant to fluconazole. Hence, cross-resistance among azole-type drugs is an emerging issue for managing fungal infections.

Zebrafish Egg Infection Model for Studying Candida albicans Adhesion Factors.

Disseminated candidiasis is associated with 30-40% mortality in severely immunocompromised patients. Among the causal agents, Candida albicans is the dominant one. Various animal models have been developed for investigating gene functions in C. albicans. Zebrafish injection models have increasingly been applied in elucidating C. albicans pathogenesis because of the conserved immunity, prolific fecundity of the zebrafish and the low costs of care systems. In this study, we established a simple, noninvasive zebrafish egg bath infection model, defined its optimal conditions, and evaluated the model with various C. albicans mutant strains. The deletion of SAP6 did not have significant effect on the virulence. By contrast, the deletion of BCR1, CPH1, EFG1, or TEC1 significantly reduced the virulence under current conditions. Furthermore, all embryos survived when co-incubated with bcr1/bcr1, cph1/cph1 efg1/efg1, efg1/efg1, or tec1/tec1 mutant cells. The results indicated that our novel zebrafish model is time-saving and cost effective.

Ndt80p is involved in L-sorbose utilization through regulating SOU1 in Candida albicans.

Ndt80p, a known transcriptional factor, regulates various targets involved in stress responses, filamentous growth, and virulence in Candida albicans. Potential targets of Ndt80p have been identified at the transcriptional level. The present study was conducted to identify genes regulated by Ndt80p from the protein level. We found that the levels of Ahp1p, Fma1p, Hsp21p, Rfa2p, Snz1p, Sod1p, Sou1p, Trp99p, orf19.251, orf19.1862, and orf19.5620, were affected by the null mutation of NDT80 by two-dimensional polyacrylamide gel-electrophoresis analysis. Among the 11 proteins, all but Sou1p and Rfa2p are suggested to be involved in known functions of Ndt80p. Here, we demonstrate that Ndt80p plays a role in l-sorbose utilization through regulating SOU1 in C. albicans.

Yeast oropharyngeal colonization in human immunodeficiency virus-infected patients in central taiwan.

A prospective, cross-sectional study was conducted at a medical center in central Taiwan to understand the prevalence, associated factors, and microbiologic features for oropharyngeal yeast colonization in human immunodeficiency virus-infected outpatients. Oral yeast colonization was detected in 127 (45 %) patients, including 21 (16.5 %) colonized by more than one species. Of the 154 isolates, Candida albicans was the most common species (114, 74 %), followed by Candida dubliniensis (10, 6.5 %), Candida glabrata (10, 6.5 %), Candida tropicalis (7, 4.5 %), and 13 others. We found that receiving antituberculous drug (p = 0.046) or atazanavir (p = 0.045) was two predictors for patients colonized by non-C. albicans species (p = 0.005) and risking mixed yeast colonization (p = 0.009). Even though our data showed that clinical antifungal drugs remained effective in vitro against the colonizing yeasts, the increased mixed yeast colonization indicates a potential issue for controlling mixed infections in hospital settings.

An emerging issue of mixed yeast cultures.

BACKGROUND: Different yeast species have different susceptibilities to commonly prescribed antifungal drugs. Thus, it is important to accurately determine the species of pathogenic yeasts, especially when more than one species are in a specimen. METHODS: Clinically significant yeast isolates were collected via the Taiwan Surveillance of Antimicrobial Resistance of Yeasts from July to September in 2010. The identifications of isolates were assessed in the core laboratory at the National Health Research Institutes. RESULTS: Of the 1127 isolates recovered, 1088 were of Candida genus, accounting for 96.53% of the total isolates, followed by Cryptococcus (15, 1.33%), Trichosporon (12, 1.06%), Kodamaea (4, 0.35%), Pichia (4, 0.35%), and three others. In all, 38 out of 1116 (3.4%) specimens had mixed yeast cultures. One ascites specimen had three species, Candida albicans, Candida glabrata, and Candida tropicalis. In the remaining 37 specimens, 16 had a combination of C. albicans and C. glabrata, eight C. albicans and C. tropicalis, five C. glabrata and C. tropicalis, three Candida krusei and C. tropicalis, and five with different combinations. CONCLUSION: The high prevalence of cultures with mixed yeasts may be an emerging issue. Thus, to determine mixed yeast cultures in the same specimen, we highly recommend CHROMagar Candida medium to culture yeast isolates directly from the specimen.

Genotype analysis based on intergenic spacer 1 sequences of Trichosporon asahii collected in Taiwan.

Among 32 Trichosporon asahii isolates collected in four rounds of the Taiwan Surveillance of Antimicrobial Resistance of Yeasts (TSARY) studies, conducted in 1999, 2002, 2006, and 2010, five different intergenic spacer 1 (IGS1) genotypes were detected. Genotype 1 was the most common (43.8%), followed by genotypes 3 (28.1%), 7 (12.5%), 5 (9.4%), and 4 (6.3%). Interestingly, genotype 7 was more prevalent in Taiwan than in other areas (P = 0.01); while we did not find a significant association between IGS1 genotype and susceptibility to antifungal drugs, we did note that the majority of isolates of T. asahii were susceptible to both fluconazole and voriconazole, consistent with previous reports. A higher proportion of isolates (P = 0.05) collected in 2010 (4/12, 33.3%) had high amphotericin B MICs (≥ 2 mg/l) than those collected in the previous three TSARYs (1/21, 5%). Hence, the new data of genotypes and drug susceptibilities in the present study may contribute to the epidemiology of T. asahii.

Species distribution and drug susceptibilities of Candida isolates in TSARY 2010.

Susceptibilities to antifungal drugs of 1083 Candida isolates collected in Taiwan Surveillance of Antimicrobial Resistance of Yeasts in 2010 were determined. There were 422 (39%) C. albicans, 270 (24.9%) C. tropicalis, 258 (23.8%) C. glabrata, 87 (8%) C. parapsilosis, 18 (1.7%) C. krusei, and 28 (2.6%) of 13 other species. In the present study, we have applied species-specific clinical breakpoints for common species and epidemiological cutoff values for rare species. We found that majority of isolates were susceptible to tested drugs. A total of 15, 3, 2, and 0 isolates were not susceptible to fluconazole, voriconazole, amphotericin B, and anidulafungin, respectively. We found that three of the four fluconazole non-susceptible C. albicans isolates were resistant to voriconazole. Hence, there is an issue of cross-resistance among azole-type drugs.