Displaying publications 1 - 20 of 33 in total

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  1. Chan CL, Yew SM, Na SL, Tan YC, Lee KW, Yee WY, et al.
    Genome Announc, 2014;2(2).
    PMID: 24744321 DOI: 10.1128/genomeA.00074-14
    Ochroconis constricta is a soilborne dematiaceous fungus that has never been reported to be associated with human infection. Here we report the first draft genome sequence of strain UM 578, isolated from human skin scraping. The genomic information revealed will contribute to a better understanding of this species.
  2. Chan CL, Yew SM, Ngeow YF, Na SL, Lee KW, Hoh CC, et al.
    BMC Genomics, 2015 Nov 18;16:966.
    PMID: 26581579 DOI: 10.1186/s12864-015-2200-2
    BACKGROUND: Daldinia eschscholtzii is a wood-inhabiting fungus that causes wood decay under certain conditions. It has a broad host range and produces a large repertoire of potentially bioactive compounds. However, there is no extensive genome analysis on this fungal species.

    RESULTS: Two fungal isolates (UM 1400 and UM 1020) from human specimens were identified as Daldinia eschscholtzii by morphological features and ITS-based phylogenetic analysis. Both genomes were similar in size with 10,822 predicted genes in UM 1400 (35.8 Mb) and 11,120 predicted genes in UM 1020 (35.5 Mb). A total of 751 gene families were shared among both UM isolates, including gene families associated with fungus-host interactions. In the CAZyme comparative analysis, both genomes were found to contain arrays of CAZyme related to plant cell wall degradation. Genes encoding secreted peptidases were found in the genomes, which encode for the peptidases involved in the degradation of structural proteins in plant cell wall. In addition, arrays of secondary metabolite backbone genes were identified in both genomes, indicating of their potential to produce bioactive secondary metabolites. Both genomes also contained an abundance of gene encoding signaling components, with three proposed MAPK cascades involved in cell wall integrity, osmoregulation, and mating/filamentation. Besides genomic evidence for degrading capability, both isolates also harbored an array of genes encoding stress response proteins that are potentially significant for adaptation to living in the hostile environments.

    CONCLUSIONS: Our genomic studies provide further information for the biological understanding of the D. eschscholtzii and suggest that these wood-decaying fungi are also equipped for adaptation to adverse environments in the human host.

  3. Gan GG, Kamarulzaman A, Goh KY, Ng KP, Na SL, Soo-Hoo TS
    Med J Malaysia, 2002 Mar;57(1):118-22.
    PMID: 14569730
    We report a case of an invasive infection with non-sporulating Chrysosporium species in a patient who was treated with chemotherapy for relapsed acute lymphoblastic leukemia. This patient presented with a persistent lobar pneumonia, skin lesions, and possible involvement of the central nervous system. The patient responded to treatment with amphotericin B and oral itraconazole.
  4. Kuan CS, Ismail R, Kwan Z, Yew SM, Yeo SK, Chan CL, et al.
    PLoS One, 2016;11(6):e0156119.
    PMID: 27280438 DOI: 10.1371/journal.pone.0156119
    A yeast-like organism was isolated from the skin scraping sample of a stasis dermatitis patient in the Mycology Unit Department of Medical Microbiology, University Malaya Medical Centre (UMMC), Kuala Lumpur, Malaysia. The isolate produced no pigment and was not identifiable using chromogenic agar and API 20C AUX. The fungus was identified as Metschnikowia sp. strain UM 1034, which is close to that of Metschnikowia drosophilae based on ITS- and D1/D2 domain-based phylogenetic analysis. However, the physiology of the strain was not associated to M. drosophilae. This pathogen exhibited low sensitivity to all tested azoles, echinocandins, 5-flucytosine and amphotericin B. This study provided insight into Metschnikowia sp. strain UM 1034 phenotype profiles using a Biolog phenotypic microarray (PM). The isolate utilized 373 nutrients of 760 nutrient sources and could adapt to a broad range of osmotic and pH environments. To our knowledge, this is the first report of the isolation of Metschnikowia non-pulcherrima sp. from skin scraping, revealing this rare yeast species as a potential human pathogen that may be misidentified as Candida sp. using conventional methods. Metschnikowia sp. strain UM 1034 can survive in flexible and diverse environments with a generalist lifestyle.
  5. Kuan CS, Yew SM, Toh YF, Chan CL, Lim SK, Lee KW, et al.
    PLoS One, 2015;10(12):e0145932.
    PMID: 26716988 DOI: 10.1371/journal.pone.0145932
    Peritonitis is the leading complication of peritoneal dialysis, which is primarily caused by bacteria rather than fungi. Peritonitis is responsible for approximately 18% of the infection-related mortality in peritoneal dialysis patients. In this paper, we report the isolation of a rare fungus, Quambalaria cyanescens, from the peritoneal fluid of a man after he switched from continuous ambulatory peritoneal dialysis to nocturnal intermittent peritoneal dialysis. Based on the morphological examination and multigene phylogeny, the clinical isolate was confirmed as Q. cyanescens. This pathogen exhibited low sensitivity to all tested echinocandins and 5-flucytosine. Interestingly, morphological characterization revealed that Q. cyanescens UM 1095 produced different pigments at low temperatures (25°C and 30°C) on various culture media. It is important to monitor the emergence of this rare fungus as a potential human pathogen in the tropics. This study provides insight into Q. cyanescens UM 1095 phenotype profiles using a Biolog phenotypic microarray (PM). Of the 760 nutrient sources tested, Q. cyanescens UM 1095 utilized 42 compounds, and the fungus can adapt to a broad range of osmotic and acidic environments. To our knowledge, this is the first report of the isolation of Q. cyanescens from peritoneal fluid, revealing this rare fungus as a potential human pathogen that may be misidentified using conventional methods. The detailed morphological, molecular and phenotypic characterization of Q. cyanescens UM 1095 provides the basis for future studies on its biology, lifestyle, and potential pathogenicity.
  6. Kuan CS, Cham CY, Singh G, Yew SM, Tan YC, Chong PS, et al.
    PLoS One, 2016;11(8):e0161008.
    PMID: 27570972 DOI: 10.1371/journal.pone.0161008
    Cladophialophora bantiana is a dematiaceous fungus with a predilection for causing central nervous system (CNS) infection manifesting as brain abscess in both immunocompetent and immunocompromised patients. In this paper, we report comprehensive genomic analyses of C. bantiana isolated from the brain abscess of an immunocompetent man, the first reported case in Malaysia and Southeast Asia. The identity of the fungus was determined using combined morphological analysis and multilocus phylogeny. The draft genome sequence of a neurotrophic fungus, C. bantiana UM 956 was generated using Illumina sequencing technology to dissect its genetic fundamental and basic biology. The assembled 37.1 Mb genome encodes 12,155 putative coding genes, of which, 1.01% are predicted transposable elements. Its genomic features support its saprophytic lifestyle, renowned for its versatility in decomposing hemicellulose and pectin components. The C. bantiana UM 956 was also found to carry some important putative genes that engaged in pathogenicity, iron uptake and homeostasis as well as adaptation to various stresses to enable the organism to survive in hostile microenvironment. This wealth of resource will further catalyse more downstream functional studies to provide better understanding on how this fungus can be a successful and persistent pathogen in human.
  7. Kuan CS, Ng KP, Yew SM, Umar Meleh H, Seow HF, How KN, et al.
    Braz J Microbiol, 2023 Sep;54(3):1351-1372.
    PMID: 37351789 DOI: 10.1007/s42770-023-01032-z
    Neoscytalidium dimidiatum and Bipolaris species are fungal plant pathogens that have been reported to cause human diseases. Recently, we have isolated numerous N. dimidiatum and Bipolaris species from the skin scrapings and nails of different patients. In this work, we have sequenced the genome of one strain of N. dimidiatum. The sequenced genome was compared to that of a previously reported Bipolaris papendorfii genome for a better understanding of their complex lifestyle and broad host-range pathogenicity. Both N. dimidiatum UM 880 (~ 43 Mb) and B. papendorfii UM 226 (~ 33 Mb) genomes include 11,015-12,320 putative coding DNA sequences, of which 0.51-2.49% are predicted transposable elements. Analysis of secondary metabolism gene clusters revealed several genes involved in melanin biosynthesis and iron uptake. The arsenal of CAZymes related to plants pathogenicity is comparable between the species, including genes involved in hemicellulose and pectin decomposition. Several important gene encoding keratinolytic peptidases were identified in N. dimidiatum and B. papendorfii, reflecting their potential pathogenic role in causing skin and nail infections. In this study, additional information on the metabolic features of these two species, such as nutritional profiling, pH tolerance, and osmotolerant, are revealed. The genomic characterization of N. dimidiatum and B. papendorfii provides the basis for the future functional studies to gain further insights as to what makes these fungi persist in plants and why they are pathogenic to humans.
  8. Kuan CS, Yew SM, Toh YF, Chan CL, Ngeow YF, Lee KW, et al.
    DNA Res, 2015 Jun;22(3):219-32.
    PMID: 25922537 DOI: 10.1093/dnares/dsv007
    Bipolaris papendorfii has been reported as a fungal plant pathogen that rarely causes opportunistic infection in humans. Secondary metabolites isolated from this fungus possess medicinal and anticancer properties. However, its genetic fundamental and basic biology are largely unknown. In this study, we report the first draft genome sequence of B. papendorfii UM 226 isolated from the skin scraping of a patient. The assembled 33.4 Mb genome encodes 11,015 putative coding DNA sequences, of which, 2.49% are predicted transposable elements. Multilocus phylogenetic and phylogenomic analyses showed B. papendorfii UM 226 clustering with Curvularia species, apart from other plant pathogenic Bipolaris species. Its genomic features suggest that it is a heterothallic fungus with a putative unique gene encoding the LysM-containing protein which might be involved in fungal virulence on host plants, as well as a wide array of enzymes involved in carbohydrate metabolism, degradation of polysaccharides and lignin in the plant cell wall, secondary metabolite biosynthesis (including dimethylallyl tryptophan synthase, non-ribosomal peptide synthetase, polyketide synthase), the terpenoid pathway and the caffeine metabolism. This first genomic characterization of B. papendorfii provides the basis for further studies on its biology, pathogenicity and medicinal potential.
  9. Looi HK, Toh YF, Yew SM, Na SL, Tan YC, Chong PS, et al.
    PeerJ, 2017;5:e2841.
    PMID: 28149676 DOI: 10.7717/peerj.2841
    Corynespora cassiicola is a common plant pathogen that causes leaf spot disease in a broad range of crop, and it heavily affect rubber trees in Malaysia (Hsueh, 2011; Nghia et al., 2008). The isolation of UM 591 from a patient's contact lens indicates the pathogenic potential of this dematiaceous fungus in human. However, the underlying factors that contribute to the opportunistic cross-infection have not been fully studied. We employed genome sequencing and gene homology annotations in attempt to identify these factors in UM 591 using data obtained from publicly available bioinformatics databases. The assembly size of UM 591 genome is 41.8 Mbp, and a total of 13,531 (≥99 bp) genes have been predicted. UM 591 is enriched with genes that encode for glycoside hydrolases, carbohydrate esterases, auxiliary activity enzymes and cell wall degrading enzymes. Virulent genes comprising of CAZymes, peptidases, and hypervirulence-associated cutinases were found to be present in the fungal genome. Comparative analysis result shows that UM 591 possesses higher number of carbohydrate esterases family 10 (CE10) CAZymes compared to other species of fungi in this study, and these enzymes hydrolyses wide range of carbohydrate and non-carbohydrate substrates. Putative melanin, siderophore, ent-kaurene, and lycopene biosynthesis gene clusters are predicted, and these gene clusters denote that UM 591 are capable of protecting itself from the UV and chemical stresses, allowing it to adapt to different environment. Putative sterigmatocystin, HC-toxin, cercosporin, and gliotoxin biosynthesis gene cluster are predicted. This finding have highlighted the necrotrophic and invasive nature of UM 591.
  10. Lotfalikhani A, Khosravi Y, Sabet NS, Na SL, Ng KP, Tay ST
    Trop Biomed, 2018 Dec 01;35(4):1123-1130.
    PMID: 33601859
    Candida glabrata has been reported as the second or third most common yeast species isolated from patients with vaginitis and invasive candidiasis. This study was aimed to determine the genetic diversity, antifungal susceptibility and enzymatic profiles of C. glabrata isolated from vaginal and blood samples in the Medical Microbiology Diagnostic Laboratory, University Malaya Medical Centre. A random amplified polymorphic DNA (RAPD) analysis method, using M13 and (GTG)5 primers, was used for strain differentiation of C. glabrata isolates. Antifungal susceptibility testing of C. glabrata isolates was determined using E-test against amphotericin B, caspofungin, fluconazole and voriconazole and microbroth dilution method against clotrimazole. The enzymic profiles of C. glabrata were determined using APIZYM semi-quantitation kit and egg-yolk agar method. A total of 14 RAPD patterns were identified amongst C. glabrata isolates investigated this study. Susceptibility to amphotericin B, caspofungin, fluconazole and voriconazole was noted. Approximately one third of the isolates demonstrated resistance to clotrimazole (MIC>=1 µg/ml). A single isolate of C. glabrata was resistant to caspofungin (MIC:1.5 µg/ml). Enzymatic activities of acid and alkaline phosphatase, aminopeptidases, esterase and lipase and phospholipase were detected in the C. glabrata isolates. The genetic diversity and antifungal susceptibility profiles of C. glabrata isolates were presented in this study. Continued surveillance and monitoring of the incidence and antifungal resistance in C. glabrata isolates is necessary.
  11. Mohd Nor F, Tan LH, Na SL, Ng KP
    Mycopathologia, 2015 Aug;180(1-2):95-8.
    PMID: 25739670 DOI: 10.1007/s11046-015-9879-0
    Rhodotorula species are increasingly being identified as a cause of fungal infection in the central nervous system, especially in patients with compromised immunity. The diagnosis could easily be missed due to low index of suspicion, as cryptococcus meningitis and cerebral toxoplasmosis are more common amongst immunocompromised hosts. To date, there are six cases of Rhodotorula-related meningitis reported, and three are associated with human immunodeficiency virus infection. In this report, a case of a Malaysian male with underlying human immunodeficiency virus infection who developed Rhodotorula mucilaginosa meningitis is presented. High-grade fever and severe headaches were the complaints presented in three previous case reports. India ink and nigrosin stainings were performed in the two previous reports and both revealed positive results. R. mucilaginosa were isolated from the culture of the patient's cerebrospinal fluid in all three previous reports. Predominant lymphocyte infiltration in the cerebrospinal fluid examination was documented in two reports. CD4 counts were above 100/µl in two previously published reports, while another report documented CD4 count as 56/µl. Amphotericin B and itraconazole are identified to be the first line of antifungal used and as the maintenance therapy, respectively. The possibility of relapse cannot be excluded as it was reported in the first report. It was also revealed that the current case has almost similar clinical presentation and therapeutic outcome as compared to the published reports, but some differences in diagnostic details were to be highlighted.
  12. Ng KP, Yew SM, Chan CL, Soo-Hoo TS, Na SL, Hassan H, et al.
    Eukaryotic Cell, 2012 Jun;11(6):828.
    PMID: 22645233 DOI: 10.1128/EC.00133-12
    Pleosporales is the largest order in the fungal class Dothideomycetes. We report the 36,814,818-bp draft genome sequence and gene annotation of UM1110, a Pleosporales isolate associated with unclassified genera that is potentially a new fungal species. Analysis of the genome sequence led to the finding of genes associated with fungal adhesive proteins, secreted proteases, allergens, and pseudohyphal development.
  13. Ng KP, Ngeow YF, Yew SM, Hassan H, Soo-Hoo TS, Na SL, et al.
    Eukaryotic Cell, 2012 May;11(5):703-4.
    PMID: 22544898 DOI: 10.1128/EC.00074-12
    Daldinia eschscholzii is an invasive endophyte that is most commonly found in plant tissues rich in secondary metabolites. We report the draft genome sequence of D. eschscholzii isolated from blood culture. The draft genome is 35,494,957 bp in length, with 42,898,665 reads, 61,449 contigs, and a G+C content of 46.8%. The genome was found to contain a high abundance of genes associated with plant cell wall degradation enzymes, mycotoxin production, and antifungal drug resistance.
  14. Ng KP, Yew SM, Chan CL, Soo-Hoo TS, Na SL, Hassan H, et al.
    Eukaryotic Cell, 2012 May;11(5):705-6.
    PMID: 22544899 DOI: 10.1128/EC.00081-12
    Cladosporium sphaerospermum is one of the most widely distributed allergens causing serious problems in patients with respiratory tract disease. We report the 26,644,473-bp draft genome sequence and gene annotation of C. sphaerospermum UM843. Analysis of the genome sequence led to the finding of genes associated with C. sphaerospermum's melanin biosynthesis, allergens, and antifungal drug resistance.
  15. Ng KP, Yew SM, Chan CL, Tan R, Soo-Hoo TS, Na SL, et al.
    Genome Announc, 2013 Jan;1(1).
    PMID: 23409267 DOI: 10.1128/genomeA.00148-12
    Herpotrichiellaceae spp. are known to be opportunistic human pathogens. Here, we report the ~28.46-Mb draft genome of Herpotrichiellaceae sp. UM 238, isolated from human skin scraping. The UM 238 genome was found to contain many classes of protective genes that are responsible for fungal adaptation under adverse environmental conditions.
  16. Ng KP, Yew SM, Chan CL, Chong J, Tang SN, Soo-Hoo TS, et al.
    Genome Announc, 2013 Jan;1(1).
    PMID: 23405310 DOI: 10.1128/genomeA.00056-12
    The emergence of the global threat of extensively drug-resistant (XDR) Mycobacterium tuberculosis reveals weaknesses in tuberculosis management and diagnostic services. We report the draft genome sequence of the first extensively drug-resistant Mycobacterium tuberculosis strain isolated in Malaysia. The sequence was also compared against a reference strain to elucidate the polymorphism that is related to their extensive resistance.
  17. Ng KP, Soo-Hoo TS, Na SL, Tay ST, Hamimah H, Lim PC, et al.
    Mycopathologia, 2005 Jun;159(4):495-500.
    PMID: 15983734
    Hortaea werneckii is an environmental dematiaceous fungus found in the halophilic environment. It causes tinea nigra. We report the isolation of H. werneckii from blood and splenic abscess of two patients with acute myelomonocytic leukaemia. H. werneckii grew at room temperature but not at 37 degrees C, it was identified by biochemical tests, growth characteristics and the presence of conspicuous collarette intercalary on dividing yeast cells. The use of specific oligonucleotide primer Hor-F (5'-TGGACACCTTCA TAACTCTTG-3') and Hor-R (5'-TCACAACGCTTAGAGACGG-3') confirmed the two isolates were H. werneckii. The sequence for 281 nucleotide of HW299 and HW403 were 99% identical but differed only in one nucleotide. In vitro anti-fungal susceptibility testing showed that the isolates were resistant to amphotericin B and flucytosine.
  18. Ng KP, Soo-Hoo TS, Na SL, Ang LS
    Mycopathologia, 2002;155(4):203-6.
    PMID: 12650596
    A total of 576 dermatophytes were isolated from patients with a variety of skin infections from January 1993 to May 2000. Ten species of dermatophytes were identified: Epidermophyton floccosum (0.7%), Microsporum audouinii (1.1%), M. canis (3.1%), M. gypseum (0.3%), Trichophyton concentricum (3.5%), T. equinum (0.2%), T. mentagrophytes (36.1%), T. rubrum (53.8%), T. verrucosum (0.2) and T. violaceum (1.0%). The body sites most frequently affected by dermatophytes were the buttocks, nails and trunk. Anthropophilic dermatophytes made up 60.1% of the isolates; the most common species was T. rubrum, T. mentagrophytes and M. canis were the two main zoophilic dermatophytes. T. mentagrophytes was isolated from all body sites except the scalp. M. canis was found to be associated with domestic dogs and was not isolated from ethnic Malays. The only geophilic dermatophyte was M. gypseum, an uncommon dermatophyte associated with tinea pedis.
  19. Ng KP, Saw TL, Na SL, Soo-Hoo TS
    Mycopathologia, 2001;149(3):141-6.
    PMID: 11307597
    A total of 102 Candida species were isolated from blood cultures from January 1997 to October 1999. Using assimilation of carbohydrate test, 52 (51.0%) of the Candida sp. were identified as C. parapsilosis, 25.5% (26) were C. tropicalis. C. albicans made up 11.8% (12), 6.9% (7) were C. rugosa, 3.8% (4) C. glabrata and 1% (1) C. guilliermondii. No C. dubliniensis was found in the study. In vitro antifungal susceptibility tests showed that all Candida species were sensitive to nystatin, amphotericin B and ketoconazole. Although all isolates remained sensitive to fluconazole, intermediate susceptibility was found in 3 C. rugosa isolates. Antifungal agents with high frequency of resistance were econazole, clotrimazole, miconazole and 5-fluorocytosine. Candida species found to have resistance to these antifungal agents were non-C. albicans.
  20. Ng KP, Soo-Hoo TS, Na SL, Gan GG, Sangkar JV, Teh AKH
    Med J Malaysia, 2003 Oct;58(4):608-12.
    PMID: 15190640
    Scopulariopsis brevicaulis is a soil fungus normally associated with onychomycosis. It causes subcutaneous infection in immunocompromised patients and is rarely isolated from blood. A case of systemic Scopulariopsis brevicaulis infection was reported in a patient with acute myeloid leukemia. The patient developed persistent fever that did not respond to wide spectrum antibiotics and amphotericin B. Scopulariopsis brevicaulis was the only pathogen isolated from blood cultures. The fever subsided with itraconazole and there was no recurrence of fungal infection with prolonged maintenance of oral itraconazole.
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