Browsing by Author "Lin, Chih-Chao"

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An emerging issue of mixed yeast cultures
(2014-08-01)
Yang, Yun-Liang
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Chu, Wen-Li
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Lin, Chih-Chao
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Tsai, Sheng-Hua
;
Chang, Te-Pin
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. Copyright (C) 2013, Taiwan Society of Microbiology. Published by Elsevier Taiwan LLC. All rights reserved.
Comparison of Human and Soil Candida tropicalis Isolates with Reduced Susceptibility to Fluconazole
(2012-04-05)
Yang, Yun-Liang
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Lin, Chih-Chao
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Chang, Te-Pin
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Lauderdale, Tsai-Ling
;
Chen, Hui-Ting
Infections caused by treatment-resistant non-albicans Candida species, such as C. tropicalis, has increased, which is an emerging challenge in the management of fungal infections. Genetically related diploid sequence type (DST) strains of C. tropicalis exhibiting reduced susceptibility to fluconazole circulated widely in Taiwan. To identify the potential source of these wildly distributed DST strains, we investigated the possibility of the presence in soil of such C. tropicalis strains by pulsed field gel electrophoresis (PFGE) and DST typing methods. A total of 56 C. tropicalis isolates were recovered from 26 out of 477 soil samples. Among the 18 isolates with reduced susceptibility to fluconazole, 9 belonged to DST149 and 3 belonged to DST140. Both DSTs have been recovered from our previous studies on clinical isolates from the Taiwan Surveillance of Antimicrobial Resistance of Yeasts (TSARY) program. Furthermore, these isolates were more resistant to agricultural azoles. We have found genetically related C. tropicalis exhibiting reduced susceptibility to fluconazole from the human hosts and environmental samples. Therefore, to prevent patients from acquiring C. tropicalis with reduced susceptibility to azoles, prudent use of azoles in both clinical and agricultural settings is advocated.
Mixed yeast infections in Taiwan
(2018-08-01)
Yang, Yun-Liang
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Chu, Wen-Li
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Lin, Chih-Chao
;
Zhou, Zi-Li
;
Chen, Pei-Ning
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.
Predisposing factors for oropharyngeal colonization of yeasts in human immunodeficiency virus-infected patients: A prospective cross-sectional study
(2013-04-01)
Lin, Jiun-Nong
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Lin, Chih-Chao
;
Lai, Chung-Hsu
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Yang, Yun-Liang
;
Chen, Hui-Ting
Background: Oropharyngeal candidiasis continues to be a major opportunistic infection in human immunodeficiency virus (HIV)-infected patients. The objectives of this study were to investigate the prevalence, associated factors, and microbiologic features for oropharyngeal yeast colonization in HIV-infected patients. Methods: From October to December 2009, consecutive HIV-infected patients older than 18 years were recruited in this study. Demographic information, underlying conditions, and clinical histories were collected. Oropharyngeal swab cultures for yeasts and antifungal drug susceptibilities of the isolates were performed. Results: Of the 105 HIV-infected patients, 54 (51.4%) were colonized with yeasts, including 11 patients (20.4%) with more than one species. Among the 68 isolates, Candida albicans accounted for 73.5%, followed by Candida tropicalis (5.9%), Candida glabrata (5.9%), and Candida dubliniensis (4.4%). There were 7.5% and 6% Candida isolates resistant to fluconazole and voriconazole, respectively. All of the Candida isolates were susceptible to amphotericin B. A higher prevalence of yeast colonization was noted in patients with a CD4 cell count <= 200 cells/mu L (p = 0.032). Multivariate regression analysis showed that intravenous drug use was an independent associated factor for oropharyngeal yeast colonization (odds ratio, 5.35; 95% confidence interval, 1.39-20.6; p = 0.015), as well as protease inhibitor-containing anti-retroviral therapy (odds ratio, 3.59; 95% confidence interval, 1.41-9.12; p = 0.007). Conclusion: Despite previous studies showing that protease inhibitors decreased Candida adhesion to epithelial cells in vitro, the current study found protease inhibitor-containing anti-retroviral therapy predisposed to oropharyngeal yeast colonization in HIV-infected patients. Copyright (C) 2012, Taiwan Society of Microbiology. Published by Elsevier Taiwan LLC. All rights reserved.
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
(2017-01-01)
Wu, Chi-Jung
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Ko, Wen-Chien
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Ho, Mao-Wang
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Lin, Hsi-Hsun
;
Yang, Yun-Liang
Human immuodeficency virus (HIV)-infected patients receiving highly active antiretroviral therapy (HAART) and community-associated methicillin-resistant Staphylococcus aureus (CAMRSA) 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/mm(3). 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.
Rep1p negatively regulating MDR1 efflux pump involved in drug resistance in Candida albicans
(2009-09-01)
Chen, Chia-Geun
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Yang, Yun-Liang
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Tseng, Kuo-Yun
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Shih, Hsin-I
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Liou, Ci-Hong
Overexpression of MDR1 efflux pump is a major mechanism contributing to drug resistance in Candida albicans, the most common human fungal pathogen. To elucidate the regulatory pathway of drug resistance, we have identified a negative regulator of MDR1 and named it Regulator of Efflux Pump 1 (REP1). Overexpression of REPI in Saccharomyces cerevisiae increased susceptibility to fluconazole. Furthermore, null mutations on REP1 decreased the susceptibility to antifungal drugs in C albicans resulting from increased expression of MDR1 mRNA. Hence, Rep1p is involved in drug resistance by negatively regulating MDR1 in C albicans. (c) 2009 Elsevier Inc. All rights reserved.
Species distribution and drug susceptibilities of Candida isolates in TSARY 2010
(2013-06-01)
Yang, Yun-Liang
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Chen, Hui-Ting
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Lin, Chih-Chao
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Chu, Wen-Li
;
Lo, Hsiu-Jung
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. (C) 2013 Elsevier Inc. All rights reserved.
The distribution and drug susceptibilities of clinical Candida species in TSARY 2014
(2016-12)
Zhou, Zi-Li
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Lin, Chih-Chao
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Chu, Wen-Li
;
Yang, Yun-Liang
;
Lo, Hsiu-Jung
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. (C) 2016 Published by Elsevier Inc.
The survey of tinea capitis and scalp dermatophyte carriage in nursing home residents
(2018-02-01)
Lin, Chien-Yio
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Lo, Hsiu-Jung
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Tu, Ming-Gene
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Ju, Yu-Ming
;
Fan, Yun-Chen
Tinea capitis is a contagious dermatophyte infection of scalp and associated hairs. On the other hand, asymptomatic carriage is a status of positive dermatophyte scalp culture, but without signs or symptoms of tinea capitis, and no evidence of hair shaft invasion confirmed by direct microscopy. Tinea capitis and asymptomatic carriage mostly occur in children, but adult females are becoming another population in recent decades. In this study, we focused on the prevalence and related fungi of tinea capitis and asymptomatic carriage in elderly by the shampoo brush method, as well as the source of transmission, in 10 nursing home residents. Two hundred and thirteen residents were screened, and 186 isolates were identified, of which only three were dermatophytes (1.4%). The scalp dermatophyte isolates were identified as Trichophyton rubrum by morphological characters and sequences comparisons in all three cases. After revisiting, these cases were proved to be asymptomatic carriers by negative microscopic and culture examination; however, two cases were found to have concurrent tinea pedis and onychomycosis, which were identified as T. rubrum and Trichophyton interdigitale. The source of the T. rubrum scalp carriage may come from tinea elsewhere on the body of the same subject or from other people in the same institute. Finding and treating the source of carriage, as well as treating scalp carriage patients according to the colony counts, may help prevent disease spreading.
Yeast Oropharyngeal Colonization in Human Immunodeficiency Virus-Infected Patients in Central Taiwan
(2014-06-01)
Ho, Mao-Wang
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Yang, Yun-Liang
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Lin, Chih-Chao
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Chi, Chih-Yu
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Chen, Hui-Ting
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.