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Fulltext In Vitro Analysis of Metabolites Secreted during Infection of Lung Epithelial Cells by Cryptococcus neoformans

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: Meningitis, Cryptococcal/microbiology
Epidemiology of cryptococcosis in Malaysia

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: Meningitis, Cryptococcal/microbiology*
Fulltext Lessons learned about opportunistic infections in southeast Asia

Nissapatorn V

Southeast Asian J Trop Med Public Health, 2008 Jul;39(4):625-41.
PMID: 19058599

Southeast Asia is a region where the number of people infected with HIV/AIDS is one of the fastest growing in the world. Tuberculosis (TB) has grown along with the HIV epidemic. TB is not only the most common AIDS-defining illness but is also the leading cause of morbidity and mortality in AIDS patients. Cryptococcosis (meningitis or disseminated) is one of the most common opportunistic infections in AIDS patients. Cryptococcal meningitis is the first in the differential diagnosis considered with meningeal irritation. Penicillosis, a unique systemic mycosis, is an important emerging public health problem and has been classified as an AIDS defining illness in endemic areas like Thailand. Pneumocystis carinii (jiroveci) pneumonia has been one of the most important opportunistic infections in AIDS patients. Among parasitic infections, cryptosporidiosis is the most common intestinal protozoan infection relating to diarrhea in AIDS patients and toxoplasmosis is the only parasitic infection of the nervous system with a substantial incidence, up to 14.8%. Cytomegalovirus (CMV) retinitis has a lower prevalence compared to other opportunistic infections. In the era of highly active antiretroviral therapy (HAART), the incidence of opportunistic infections has significantly reduced in the past few years. Subsequently, the phenomena of immune restoration inflammatory syndrome (IRIS) in AIDS patients has been reported in this region as a result of HAART.

Matched MeSH terms: Meningitis, Cryptococcal/microbiology
Fulltext Tuberculous meningitis is a major cause of mortality and morbidity in adults with central nervous system infections in Kota Kinabalu, Sabah, Malaysia: an observational study

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: Meningitis, Cryptococcal/microbiology