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  1. MUIR CS, RANSOME GA
    Med J Malaya, 1959 Dec;14:125-34.
    PMID: 14425049
    Matched MeSH terms: Cryptococcus neoformans*
  2. Movahed E, Munusamy K, Tan GM, Looi CY, Tay ST, Wong WF
    PLoS One, 2015;10(9):e0137457.
    PMID: 26360021 DOI: 10.1371/journal.pone.0137457
    The infection of Cryptococcus neoformans is acquired through the inhalation of desiccated yeast cells and basidiospores originated from the environment, particularly from bird's droppings and decaying wood. Three environmental strains of C. neoformans originated from bird droppings (H4, S48B and S68B) and C. neoformans reference clinical strain (H99) were used for intranasal infection in C57BL/6 mice. We showed that the H99 strain demonstrated higher virulence compared to H4, S48B and S68B strains. To examine if gene expression contributed to the different degree of virulence among these strains, a genome-wide microarray study was performed to inspect the transcriptomic profiles of all four strains. Our results revealed that out of 7,419 genes (22,257 probes) examined, 65 genes were significantly up-or down-regulated in H99 versus H4, S48B and S68B strains. The up-regulated genes in H99 strain include Hydroxymethylglutaryl-CoA synthase (MVA1), Mitochondrial matrix factor 1 (MMF1), Bud-site-selection protein 8 (BUD8), High affinity glucose transporter 3 (SNF3) and Rho GTPase-activating protein 2 (RGA2). Pathway annotation using DAVID bioinformatics resource showed that metal ion binding and sugar transmembrane transporter activity pathways were highly expressed in the H99 strain. We suggest that the genes and pathways identified may possibly play crucial roles in the fungal pathogenesis.
    Matched MeSH terms: Cryptococcus neoformans/classification; Cryptococcus neoformans/drug effects; Cryptococcus neoformans/genetics*; Cryptococcus neoformans/isolation & purification; Cryptococcus neoformans/pathogenicity
  3. Chin CS, Cheong YM, Wong YH
    Med J Malaysia, 1989 Sep;44(3):194-8.
    PMID: 2696871
    Thirty six clinical isolates of Cryptococcus neoformans were tested for their susceptibility to 5-fluorocytosine and amphotericin B by the determination of minimum inhibitory concentrations and minimum fungicidal concentrations. 22.2% of the isolates were resistant to 5-fluorocytosine and 36.1% indicated 5-fluorocytosine tolerance. All strains were sensitive to amphotericin B.
    Matched MeSH terms: Cryptococcus neoformans/drug effects*
  4. Movahed E, Tan GM, Munusamy K, Yeow TC, Tay ST, Wong WF, et al.
    Front Microbiol, 2016;7:360.
    PMID: 27047474 DOI: 10.3389/fmicb.2016.00360
    Cryptococcus neoformans is an opportunistic fungus that causes fatal meningoencephalitis especially in AIDS patients. There is an increasing need for discovery of new anti-cryptococcal drugs due to emergence of resistance cases in recent years. In this study, we aim to elucidate the antifungal effect of triclosan against C. neoformans.
    Matched MeSH terms: Cryptococcus neoformans
  5. Tay ST, Lim HC, Tajuddin TH, Rohani MY, Hamimah H, Thong KL
    Med Mycol, 2006 Nov;44(7):617-22.
    PMID: 17071555
    The molecular types and genetic heterogeneity of Cryptococcus neoformans and C. gattii clinical isolates in Malaysia were determined in this study. Of 44 C. neoformans collected between 1980 and 2003, 42 (95.5%) were molecular type VNI, 2 (4.5%) were molecular type VNII. Of 17 C.gattii isolates, 13 (76.5%) were molecular type VGI, and 4 (23.5%) were molecular type VGII. A difference was noted when comparing the molecular types of cryptococcal isolates in the earlier and recent cases of cryptococcosis. While both molecular types VNI and VGI were equally predominant in the earlier cases of cryptococcosis, VNI was the most predominant molecular type isolated from the recent cases. VNII was a new molecular type, isolated from 5.1% of the recent cases. All the bird dropping isolates were molecular type VNI. The genetic heterogeneity of the two predominant molecular types, i.e., VNI, VGI clinical isolates and bird dropping isolates of C. neoformans were further determined by polymerase chain reaction (PCR) fingerprinting method, using (GTG)5 as single primer. Two clusters of cryptococcal isolates were distinguished at 68.5% of similarity, with cluster I consisting of VNI isolates and cluster II consisting of VGI isolates. Each cluster was further subdivided into three subtypes at >/=80% of similarity. Fourteen bird dropping isolates were grouped into a subtype within VN1, sharing 82.7% of similarity with the clinical isolates. A higher degree of similarities, ranging from 93.4-97.6% was noted between 3 bird dropping isolates with the clinical isolates in another subtype. This study demonstrated the existence of various molecular types of C. neoformans isolates in Malaysia and the genetic heterogeneity within the predominant molecular types. The study also provides evidence for genetic relatedness of clinical isolates with bird dropping isolates in the environment.
    Matched MeSH terms: Cryptococcus neoformans/genetics; Cryptococcus neoformans/isolation & purification*
  6. Chan MY, Tay ST
    Mycoses, 2010 Jan;53(1):26-31.
    PMID: 19389064 DOI: 10.1111/j.1439-0507.2008.01654.x
    This study compared the enzymatic activity of clinical isolates of Cryptococcus neoformans, Cryptococcus gattii, environmental isolates of C. neoformans and non-neoformans Cryptococcus. Most of the cryptococcal isolates investigated in this study exhibited proteinase and phospholipase activities. Laccase activity was detected from all the C. neoformans and C. gattii isolates, but not from the non-neoformans Cryptococcus isolates. There was no significant difference in the proteinase, phospholipase and laccase activities of C. neoformans and C. gattii. However, significant difference in the enzymatic activities of beta-glucuronidase, alpha-glucosidase, beta-glucosidase and N-acetyl-beta-glucosaminidase between C. neoformans and C. gattii isolates was observed in this study. Environmental isolates of C. neoformans exhibited similar enzymatic profiles as the clinical isolates of C. neoformans, except for lower proteinase and laccase activities.
    Matched MeSH terms: Cryptococcus neoformans/enzymology; Cryptococcus neoformans/isolation & purification
  7. Othman N, Abdullah NA, Wahab ZA
    PMID: 15916093
    An immunocompetent 5 year-old girl presented with pyrexia of unknown origin associated with headache. Initial investigations showed leukocytosis and an increased erythrocyte sedimentation rate. A Widal-Weil Felix test, blood film for malarial parasites, mycoplasma IgM antibody, cultures from blood and urine, full blood picture, Mantoux test, and chest x-ray were all negative. A lumbar puncture was done as part of a work-up for pyrexia of unknown origin. Cryptococcus neoformans was seen on India ink examination and confirmed on culture. She was treated with 10 weeks of intravenous amphotericin B and 8 weeks of fluconazole. Further immunological tests did not reveal any defect in the cell-mediated immune system. C. neoformans meningitis may present with non-specific symptoms and should be considered in a work-up for pyrexia of unknown origin.
    Matched MeSH terms: Cryptococcus neoformans/isolation & purification; Cryptococcus neoformans/pathogenicity
  8. Liew KL, Jee JM, Yap I, Yong PV
    PLoS One, 2016;11(4):e0153356.
    PMID: 27054608 DOI: 10.1371/journal.pone.0153356
    Cryptococcus neoformans is an encapsulated basidiomycetous yeast commonly associated with pigeon droppings and soil. The opportunistic pathogen infects humans through the respiratory system and the metabolic implications of C. neoformans infection have yet to be explored. Studying the metabolic profile associated with the infection could lead to the identification of important metabolites associated with pulmonary infection. Therefore, the aim of the study was to simulate cryptococcal infection at the primary site of infection, the lungs, and to identify the metabolic profile and important metabolites associated with the infection at low and high multiplicity of infections (MOI). The culture supernatant of lung epithelial cells infected with C. neoformans at MOI of 10 and 100 over a period of 18 hours were analysed using gas chromatography mass spectrometry. The metabolic profiles obtained were further analysed using multivariate analysis and the pathway analysis tool, MetaboAnalyst 2.0. Based on the results from the multivariate analyses, ten metabolites were selected as the discriminatory metabolites that were important in both the infection conditions. The pathways affected during early C. neoformans infection of lung epithelial cells were mainly the central carbon metabolism and biosynthesis of amino acids. Infection at a higher MOI led to a perturbance in the β-alanine metabolism and an increase in the secretion of pantothenic acid into the growth media. Pantothenic acid production during yeast infection has not been documented and the β-alanine metabolism as well as the pantothenate and CoA biosynthesis pathways may represent underlying metabolic pathways associated with disease progression. Our study suggested that β-alanine metabolism and the pantothenate and CoA biosynthesis pathways might be the important pathways associated with cryptococcal infection.
    Matched MeSH terms: Cryptococcus neoformans/physiology*
  9. Tay ST, Tanty Haryanty T, Ng KP, Rohani MY, Hamimah H
    Mycoses, 2006 Jul;49(4):324-30.
    PMID: 16784448
    The in vitro susceptibilities of Malaysian clinical isolates of Cryptococcus neoformans var. grubii and C . gattii to five antifungal drugs (amphotericin B, flucytosine, fluconazole, itraconazole and ketoconazole) were determined using the Etest method. None of the Malaysian isolates was resistant to amphotericin B and ketoconazole. Isolates resistant to flucytosine, fluconazole and itraconazole were observed in this study. Minimum inhibition concentrations (MICs) of > or = 32 microg ml(-1) against flucytosine, > or = 64 microg ml(-1) against fluconazole and > or = 1 microg ml(-1) against itraconazole were noted in four (8.3%), two (4.2%) and one (2.1%) isolates respectively. There was no significant difference in the MICs for both Cryptococcus species (P > 0.05), indicating that C. gattii was as susceptible as var. grubii to all the antifungal drugs tested. No significant difference in the MICs for both Cryptococcus species collected from 1980 to 1990 and 2002 to 2004 were observed (P > 0.05).
    Matched MeSH terms: Cryptococcus neoformans/drug effects*
  10. Tay ST, Chai HC, Na SL, Hamimah H, Rohani MY, Soo-Hoo TS
    Mycopathologia, 2005 Jun;159(4):509-13.
    PMID: 15983736
    The occurrence of Cryptococcus neoformans in bird excreta in Klang valley, Malaysia was determined in this study. Of 544 samples of bird excreta collected from a local zoo, pet shops and public areas, 20 strains of C. neoformans were isolated. All C. neoformans strains were serotype A and thus identified as C. neoformans variety grubii. All did not produce color changes on canavanine-glycine-bromothymol blue agar. All were of alpha-mating types, as determined by a pheromone-specific PCR assay. The antifungal susceptibility testing using agar diffusion method Neo-sensitabs showed that all were susceptible to amphotericin B, fluconazole and itraconazole.
    Matched MeSH terms: Cryptococcus neoformans/drug effects*; Cryptococcus neoformans/isolation & purification*
  11. Choo KK, Chong PP, Ho AS, Yong PV
    Eur J Clin Microbiol Infect Dis, 2015 Dec;34(12):2421-7.
    PMID: 26463450 DOI: 10.1007/s10096-015-2497-4
    The purpose of this investigation was to characterise the interactions of Cryptococcus neoformans with mammalian host alveolar epithelial cells and alveolar macrophages, with emphasis on the roles of the cryptococcal capsule and the host cell cytoskeletons. The adherence and internalisation of C. neoformans into mammalian lung cells and the roles of host cell cytoskeletons in host-pathogen interactions were studied using in vitro models coupled with a differential fluorescence assay, fluorescence staining, immunofluorescence and drug inhibition of actin and microtubule polymerisation. Under conditions devoid of opsonin and macrophage activation, C. neoformans has a high affinity towards MH-S alveolar macrophages, yet associated poorly to A549 alveolar epithelial cells. Acapsular C. neoformans adhered to and internalised into the mammalian cells more effectively compared to encapsulated cryptococci. Acapsular C. neoformans induced prominent actin reorganisation at the host-pathogen interface in MH-S alveolar macrophages, but minimally affected actin reorganisation in A549 alveolar epithelial cells. Acapsular C. neoformans also induced localisation of microtubules to internalised cryptococci in MH-S cells. Drug inhibition of actin and microtubule polymerisation both reduced the association of acapsular C. neoformans to alveolar macrophages. The current study visualises and confirms the interactions of C. neoformans with mammalian alveolar cells during the establishment of infection in the lungs. The acapsular form of C. neoformans effectively adhered to and internalised into alveolar macrophages by inducing localised actin reorganisation, relying on the host's actin and microtubule activities.
    Matched MeSH terms: Cryptococcus neoformans
  12. Tzar, M.N., Suhaila, B., Shamsul, A.S., Azizah, M.
    MyJurnal
    Introduction: Epidemiology of fungal infections in an infectious disease reference centre is different from other institutions. This study aimed to look at the scenario of fungal infections at an infectious disease reference centre in Malaysia. Methods: All positive fungal cultures from an infectious disease reference centre were identified by routine mycology laboratory methods. Patient demographic, laboratory and clinical data were collected and analyzed. Duplicate data were excluded. Results: Middle-aged Malay males were the most common group. However, increased proportions of Chinese, Myanmar and Indonesians reduced the Malay predominance in HIV-positive group. In all patients, Candida species represented 64.1% isolates, followed by Cryptococcus neoformans (14.7%) and Penicillium marneffei (14.7%). Among HIVpositive individuals, C. neoformans (37.9%) was the most common species, followed by P. marneffei (35.6%) and all Candida species (17.2%). In contrast to other non-infectious disease reference centres, common causes of fungaemia included P. marneffei (43.5%), Candida species (25.8%), C. neoformans (24.2%) and H. capsulatum (6.5%). Conclusion: The prevalence of fungal infection at an infectious disease reference centre is different from other non-infectious disease reference centres. This may have an impact on current antifungal practice especially empiric antifungal therapy, patient morbidity and mortality.
    Matched MeSH terms: Cryptococcus neoformans
  13. Choo, K.K., Chin, V.K., Chong, P.P., Ho, S.H., Yong, V.C.
    JUMMEC, 2019;22(2):24-30.
    MyJurnal
    Cryptococcus neoformans is an encapsulated fungal pathogen that causes severe disease primarily in
    immunocompromised patients. Adherence and internalisation of microbial pathogens into host cells often
    begin with engagement of microbes to the surface receptors of host. However, the mechanisms involved
    remain poorly understood. In this study, we investigated the association of cell surface determinants of C.
    neoformans with mammalian cells. Our results showed that treatment with trypsin, but not paraformaldehyde
    or heat killing, could reduce host-cryptococci interaction, suggesting the involvement of cell surface proteins
    (CSPs) of C. neoformans in the interaction. We extended our investigations to determine the roles of CSPs
    during cryptococci-host cells interaction by extracting and conjugating CSPs of C. neoformans to latex beads.
    Conjugation of CSPs with both encapsulated and acapsular C. neoformans increased the association of latex
    beads with mammalian alveolar epithelial cells, alveolar macrophages and monocyte-derived macrophages.
    Further examination on the actin organisation of the host cells implied the involvement of actin-dependent
    phagocytosis in the internalisation of C. neoformans in CSP-conjugated latex beads. We hypothesised that
    CSPs present on the cell wall of C. neoformans mediate the adherence and actin-dependent phagocytosis
    of cryptococci by mammalian cells. Our results warrant further studies on the exact role of CSPs in the
    pathogenesis of cryptococcosis.
    Matched MeSH terms: Cryptococcus neoformans
  14. Chai HC, Tay ST
    Mycoses, 2009 Mar;52(2):166-70.
    PMID: 18643920 DOI: 10.1111/j.1439-0507.2008.01549.x
    The serological responses to Cryptococcus neoformans proteins of blood donors and HIV patients with active cryptococcosis from a tropical region were investigated in this study. Exposure to C. neoformans, an organism ubiquitous in the environment, contributes to the antibody responses observed in the blood donors. IgG responses to cryptococcal proteins were stronger than IgM responses in most sera tested in this study. A 53-kDa cryptococcal protein fragment was identified as the most immunoreactive protein on the IgM immunoblots of both blood donors and patients. Overall, there was no obvious difference in IgG responses of patients when compared with blood donors. Some immunogenic protein fragments (27.5, 76, 78 and 91.5 kDa) were detected at least two times more frequently on IgM immunoblots of patients compared with those of blood donors. It is yet to be investigated whether the proteins identified in this study may have any potential to be used as biomarker for cryptococcosis.
    Matched MeSH terms: Cryptococcus neoformans/immunology*
  15. Tay ST, Rohani MY, Hoo TS, Hamimah H
    Mycoses, 2010 Nov;53(6):509-14.
    PMID: 19627508 DOI: 10.1111/j.1439-0507.2009.01750.x
    This study describes the isolation of Cryptococcus neoformans and Cryptococcus gattii from patients with chronic meningitis who were admitted to 16 Malaysian hospitals, from 2003 to 2004. Of the 96 cryptococcal cases reported over the 2-year period, 74 (77.1%) patients were male and 45 (46.9%) patients were between 30 and 39 years old. Cryptococcosis was uncommon in children. A total of 57 (59.4%) and 23 (24.0%) patients were Malay and Chinese respectively. Human immunodeficiency virus infection was the major underlying disease reported in 36 (37.5%) patients. C. neoformans var. grubii (serotype A and molecular type VNI) was the predominant Cryptococcus species isolated from 88.5% of cryptococcal cases in this country. Cryptococcal cases due to C. neoformans var. grubii were reported from all the five regions in Malaysia, with the most number of cases reported from the central and northern regions. Cryptococcus gattii (all were serotype B and molecular types VGI/II) was isolated from all regions except the southern region. Compared with a study conducted prior to the AIDS era, our findings show substantial changes in the demographical characteristics of patients.
    Matched MeSH terms: Cryptococcus neoformans/isolation & purification*
  16. Lee HG, William T, Menon J, Ralph AP, Ooi EE, Hou Y, et al.
    BMC Infect Dis, 2016 06 16;16:296.
    PMID: 27306100 DOI: 10.1186/s12879-016-1640-x
    BACKGROUND: Central nervous system (CNS) infections are a significant contributor to morbidity and mortality globally. However, most published studies have been conducted in developed countries where the epidemiology and aetiology differ significantly from less developed areas. Additionally, there may be regional differences due to variation in the socio-economic levels, public health services and vaccination policies. Currently, no prospective studies have been conducted in Sabah, East Malaysia to define the epidemiology and aetiology of CNS infections. A better understanding of these is essential for the development of local guidelines for diagnosis and management.

    METHODS: We conducted a prospective observational cohort study in patients aged 12 years and older with suspected central nervous system infections at Queen Elizabeth Hospital, Kota Kinabalu, Sabah, Malaysia between February 2012 and March 2013. Cerebrospinal fluid was sent for microscopy, biochemistry, bacterial and mycobacterial cultures, Mycobacterium tuberculosis polymerase chain reaction (PCR), and multiplex and MassCode PCR for various viral and bacterial pathogens.

    RESULTS: A total of 84 patients with clinically suspected meningitis and encephalitis were enrolled. An aetiological agent was confirmed in 37/84 (44 %) of the patients. The most common diagnoses were tuberculous meningitis (TBM) (41/84, 48.8 %) and cryptococcal meningoencephalitis (14/84, 16.6 %). Mycobacterium tuberculosis was confirmed in 13/41 (31.7 %) clinically diagnosed TBM patients by cerebrospinal fluid PCR or culture. The acute case fatality rate during hospital admission was 16/84 (19 %) in all patients, 4/43 (9 %) in non-TBM, and 12/41 (29 %) in TBM patients respectively (p = 0.02).

    CONCLUSION: TBM is the most common cause of CNS infection in patients aged 12 years or older in Kota Kinabalu, Sabah, Malaysia and is associated with high mortality and morbidity. Further studies are required to improve the management and outcome of TBM.

    Matched MeSH terms: Cryptococcus neoformans/genetics; Cryptococcus neoformans/isolation & purification
  17. Tan, Sin Nee, Lim, Thiam Seong Christopher
    MyJurnal
    Cryptococcal meningitis is a central nervous system infection cause by Cryptococcus neoformans. Although Cryptococcus is found in bird droppings, it has never been reported for those ranchers involved in the niche swiftlet ranching industry despite having close proximity with the bird droppings. We present here a case of a 41-year-old healthy swiftlet rancher who presents with a history of prolonged fever, headache and altered behaviour of a month duration. Cerebral spinal fluid analysis revealed the presence of Cryptococcus. He was treated with intravenous amphotericin B and flucytosine and discharged well with fluconazole consolidation therapy for 8 weeks, followed by maintenance therapy for 1 year. We believe this is the first reported case of Cryptococcal meningitis (CM) occurring in an immunocompetent swiftlet rancher. This case should highlight the needs to wear a proper personal protective equipment inside a swiftlet ranch due to the constant exposure to the potential cryptococcal-rich environment. A high index of suspicion, careful history taking and physical examination focusing on neurologic assessment is key to early diagnosis and timely management of CM.
    Matched MeSH terms: Cryptococcus neoformans
  18. Movahed E, Cheok YY, Tan GMY, Lee CYQ, Cheong HC, Velayuthan RD, et al.
    BMC Immunol, 2018 Nov 08;19(1):32.
    PMID: 30409128 DOI: 10.1186/s12865-018-0269-5
    BACKGROUND: IL-17A has emerged as a key player in the pathologies of inflammation, autoimmune disease, and immunity to microbes since its discovery two decades ago. In this study, we aim to elucidate the activity of IL-17A in the protection against Cryptococcus neoformans, an opportunistic fungus that causes fatal meningoencephalitis among AIDS patients. For this purpose, we examined if C. neoformans infection triggers IL-17A secretion in vivo using wildtype C57BL/6 mice. In addition, an enhanced green fluorescence protein (EGFP) reporter and a knockout (KO) mouse models were used to track the source of IL-17A secretion and explore the protective function of IL-17A, respectively.

    RESULTS: Our findings showed that in vivo model of C. neoformans infection demonstrated induction of abundant IL-17A secretion. By examining the lung bronchoalveolar lavage fluid (BALF), mediastinal lymph node (mLN) and spleen of the IL-17A-EGFP reporter mice, we showed that intranasal inoculation with C. neoformans promoted leukocytes lung infiltration. A large proportion (~ 50%) of the infiltrated CD4+ helper T cell population secreted EGFP, indicating vigorous TH17 activity in the C. neoformans-infected lung. The infection study in IL-17A-KO mice, on the other hand, revealed that absence of IL-17A marginally boosted fungal burden in the lung and accelerated the mouse death.

    CONCLUSION: Therefore, our data suggest that IL-17A is released predominantly from TH17 cells in vivo, which plays a supporting role in the protective immunity against C. neoformans infection.

    Matched MeSH terms: Cryptococcus neoformans
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