Displaying publications 1 - 20 of 24 in total

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  1. Hassan Y, Chew SY, Than LTL
    J Fungi (Basel), 2021 Aug 17;7(8).
    PMID: 34436206 DOI: 10.3390/jof7080667
    Candida glabrata is a yeast of increasing medical relevance, particularly in critically ill patients. It is the second most isolated Candida species associated with invasive candidiasis (IC) behind C. albicans. The attributed higher incidence is primarily due to an increase in the acquired immunodeficiency syndrome (AIDS) population, cancer, and diabetic patients. The elderly population and the frequent use of indwelling medical devices are also predisposing factors. This work aimed to review various virulence factors that facilitate the survival of pathogenic C. glabrata in IC. The available published research articles related to the pathogenicity of C. glabrata were retrieved and reviewed from four credible databases, mainly Google Scholar, ScienceDirect, PubMed, and Scopus. The articles highlighted many virulence factors associated with pathogenicity in C. glabrata, including adherence to susceptible host surfaces, evading host defences, replicative ageing, and producing hydrolytic enzymes (e.g., phospholipases, proteases, and haemolysins). The factors facilitate infection initiation. Other virulent factors include iron regulation and genetic mutations. Accordingly, biofilm production, tolerance to high-stress environments, resistance to neutrophil killings, and development of resistance to antifungal drugs, notably to fluconazole and other azole derivatives, were reported. The review provided evident pathogenic mechanisms and antifungal resistance associated with C. glabrata in ensuring its sustenance and survival.
  2. Chew SY, Chee WJY, Than LTL
    J Biomed Sci, 2019 Jul 13;26(1):52.
    PMID: 31301737 DOI: 10.1186/s12929-019-0546-5
    BACKGROUND: Carbon utilization and metabolism are fundamental to every living organism for cellular growth. For intracellular human fungal pathogens such as Candida glabrata, an effective metabolic adaptation strategy is often required for survival and pathogenesis. As one of the host defence strategies to combat invading pathogens, phagocytes such as macrophages constantly impose restrictions on pathogens' access to their preferred carbon source, glucose. Surprisingly, it has been reported that engulfed C. glabrata are able to survive in this harsh microenvironment, further suggesting alternative carbon metabolism as a potential strategy for this opportunistic fungal pathogen to persist in the host.

    MAIN TEXT: In this review, we discuss alternative carbon metabolism as a metabolic adaptation strategy for the pathogenesis of C. glabrata. As the glyoxylate cycle is an important pathway in the utilization of alternative carbon sources, we also highlight the key metabolic enzymes in the glyoxylate cycle and its necessity for the pathogenesis of C. glabrata. Finally, we explore the transcriptional regulatory network of the glyoxylate cycle.

    CONCLUSION: Considering evidence from Candida albicans and Saccharomyces cerevisiae, this review summarizes the current knowledge of the glyoxylate cycle as an alternative carbon metabolic pathway of C. glabrata.

  3. Bnfaga AA, Lee KW, Than LTL, Amin-Nordin S
    J Biomed Sci, 2023 Mar 23;30(1):19.
    PMID: 36959635 DOI: 10.1186/s12929-023-00913-7
    BACKGROUND: Lactobacilli are essential microbiota that maintain a healthy, balanced vaginal environment. Vaginitis is a common infection in women during their reproductive years. Many factors are associated with vaginitis; one of them is the imbalance of microbiota in the vaginal environment. This study aimed to evaluate the antimicrobial properties of Lactobacillus delbrueckii 45E (Ld45E) against several species of bacteria, namely, Group B Streptococcus (GBS), Escherichia coli, Klebsiella spp., and Candida parapsilosis, as well as to determine the concentration of interleukin-17 (IL-17) in the presence of Ld45E.

    METHODS: The probiotic characteristics of Ld45E were evaluated by examining its morphology, pH tolerance, adhesive ability onto HeLa cells, hemolytic activity, antibiotic susceptibility, and autoaggregation ability. Then, the antimicrobial activity of Ld45E was determined using Ld45E culture, cell-free supernatant, and crude bacteriocin solution. Co-aggregation and competition ability assays against various pathogens were conducted. The immunoregulatory effects of Ld45E were analyzed by measuring the proinflammatory cytokine IL-17. A p-value less than 0.05 was considered statistical significance.

    RESULTS: Ld45E is 3-5 mm in diameter and round with a flat-shaped colony. pH 4 and 4.5 were the most favorable range for Ld45E growth within 12 h of incubation. Ld45E showed a strong adhesion ability onto HeLa cells (86%) and negative hemolytic activities. Ld45E was also sensitive to ceftriaxone, cefuroxime, ciprofloxacin, and doxycycline. We found that it had a good autoaggregation ability of 80%. Regarding antagonistic properties, Ld45E culture showed strong antimicrobial activity against GBS, E. coli, and Klebsiella spp. but only a moderate effect on C. parapsilosis. Cell-free supernatant of Ld45E exerted the most potent inhibitory effects at 40 °C against all genital pathogens, whereas bacteriocin showed a robust inhibition at 37 °C and 40 °C. The highest co-aggregation affinity was observed with GBS (81%) and E. coli (40%). Competition ability against the adhesion of GBS (80%), E. coli (76%), Klebsiella (72%), and C. parapsilosis (58%) was found. Ld45E was able to reduce the induction of the proinflammatory protein IL-17.

    CONCLUSIONS: Ld45E possessed antimicrobial and immunoregulatory properties, with better cell-on-cell activity than supernatant activity. Thus, Ld45E is a potential probiotic candidate for adjunct therapy to address vaginal infections.

  4. Boahen A, Than LTL, Loke YL, Chew SY
    Front Microbiol, 2022;13:787119.
    PMID: 35694318 DOI: 10.3389/fmicb.2022.787119
    "Unity in strength" is a notion that can be exploited to characterize biofilms as they bestow microbes with protection to live freely, escalate their virulence, confer high resistance to therapeutic agents, and provide active grounds for the production of biofilms after dispersal. Naturally, fungal biofilms are inherently resistant to many conventional antifungals, possibly owing to virulence factors as their ammunitions that persistently express amid planktonic transition to matured biofilm state. These ammunitions include the ability to form polymicrobial biofilms, emergence of persister cells post-antifungal treatment and acquisition of resistance genes. One of the major disorders affecting vaginal health is vulvovaginal candidiasis (VVC) and its reoccurrence is termed recurrent VVC (RVVC). It is caused by the Candida species which include Candida albicans and Candida glabrata. The aforementioned Candida species, notably C. albicans is a biofilm producing pathogen and habitually forms part of the vaginal microbiota of healthy women. Latest research has implicated the role of fungal biofilms in VVC, particularly in the setting of treatment failure and RVVC. Consequently, a plethora of studies have advocated the utilization of probiotics in addressing these infections. Specifically, the excreted or released compounds of probiotics which are also known as postbiotics are being actively researched with vast potential to be used as therapeutic options for the treatment and prevention of VVC and RVVC. These potential sources of postbiotics are harnessed due to their proven antifungal and antibiofilm. Hence, this review discusses the role of Candida biofilm formation in VVC and RVVC. In addition, we discuss the application of pro-, pre-, post-, and synbiotics either individually or in combined regimen to counteract the abovementioned problems. A clear understanding of the role of biofilms in VVC and RVVC will provide proper footing for further research in devising novel remedies for prevention and treatment of vaginal fungal infections.
  5. Chee WJY, Chew SY, Than LTL
    Microb Cell Fact, 2020 Nov 07;19(1):203.
    PMID: 33160356 DOI: 10.1186/s12934-020-01464-4
    Human vagina is colonised by a diverse array of microorganisms that make up the normal microbiota and mycobiota. Lactobacillus is the most frequently isolated microorganism from the healthy human vagina, this includes Lactobacillus crispatus, Lactobacillus gasseri, Lactobacillus iners, and Lactobacillus jensenii. These vaginal lactobacilli have been touted to prevent invasion of pathogens by keeping their population in check. However, the disruption of vaginal ecosystem contributes to the overgrowth of pathogens which causes complicated vaginal infections such as bacterial vaginosis (BV), sexually transmitted infections (STIs), and vulvovaginal candidiasis (VVC). Predisposing factors such as menses, pregnancy, sexual practice, uncontrolled usage of antibiotics, and vaginal douching can alter the microbial community. Therefore, the composition of vaginal microbiota serves an important role in determining vagina health. Owing to their Generally Recognised as Safe (GRAS) status, lactobacilli have been widely utilised as one of the alternatives besides conventional antimicrobial treatment against vaginal pathogens for the prevention of chronic vaginitis and the restoration of vaginal ecosystem. In addition, the effectiveness of Lactobacillus as prophylaxis has also been well-founded in long-term administration. This review aimed to highlight the beneficial effects of lactobacilli derivatives (i.e. surface-active molecules) with anti-biofilm, antioxidant, pathogen-inhibition, and immunomodulation activities in developing remedies for vaginal infections. We also discuss the current challenges in the implementation of the use of lactobacilli derivatives in promotion of human health. In the current review, we intend to provide insights for the development of lactobacilli derivatives as a complementary or alternative medicine to conventional probiotic therapy in vaginal health.
  6. Boahen A, Chew SY, Neela VK, Than LTL
    Probiotics Antimicrob Proteins, 2023 Dec;15(6):1681-1699.
    PMID: 36881331 DOI: 10.1007/s12602-023-10050-0
    Vaginal dysbiosis advocates burgeoning of devious human vaginal pathobionts like Candida species that possess multiple virulence properties and metabolic flexibility to cause infections. Inevitably, antifungal resistance may emerge due to their innate nature (e.g., biofilm formation), which assists in their virulence as well as the formation of persister cells after dispersal. In consequence, the phenomenon of biofilm involvement in vulvovaginal candidiasis (VVC) and its recurrence is becoming paramount. Lactic acid bacteria and their derivatives have proven to be hostile to Candida species. Here, we throw more light on the potency of the derivatives, i.e., cell-free supernatant (CFS) produced by an indigenously isolated vaginal Lactobacillus strain, Limosilactobacillus reuteri 29A. In the present study, we investigated the antibiofilm and antagonistic effects of L. reuteri 29A CFS, against biofilms of Candida species and in murine model of vulvovaginal candidiasis. In our in vitro biofilm study, the CFS disrupted and inhibited preformed biofilms of C. albicans and C. glabrata. Scanning electron microscopy displayed the destruction of preformed biofilms and impediment of C. albicans morphogenesis by the CFS. Gas chromatography-mass spectrometry analysis showed multiple key compounds that may act singly or synergistically. In vivo, the CFS showed no collateral damage to uninfected mice; the integrity of infected vaginal tissues was restored by the administration of the CFS as seen from the cytological, histopathological, and electron microscopical analyses. The results of this study document the potential use of CFS as an adjuvant or prophylactic option in addressing vaginal fungal infections.
  7. Fish-Low CY, Than LTL, Ling KH, Sekawi Z
    J Proteome Res, 2024 Sep 06;23(9):4027-4042.
    PMID: 39150348 DOI: 10.1021/acs.jproteome.4c00376
    Leptospirosis, a notifiable endemic disease in Malaysia, has higher mortality rates than regional dengue fever. Diverse clinical symptoms and limited diagnostic methods complicate leptospirosis diagnosis. The demand for accurate biomarker-based diagnostics is increasing. This study investigated the plasma proteome of leptospirosis patients with leptospiraemia and seroconversion compared with dengue patients and healthy subjects using isobaric tags for relative and absolute quantitation (iTRAQ)-mass spectrometry (MS). The iTRAQ analysis identified a total of 450 proteins, which were refined to a list of 290 proteins through a series of exclusion criteria. Differential expression in the plasma proteome of leptospirosis patients compared to the control groups identified 11 proteins, which are apolipoprotein A-II (APOA2), C-reactive protein (CRP), fermitin family homolog 3 (FERMT3), leucine-rich alpha-2-glycoprotein 1 (LRG1), lipopolysaccharide-binding protein (LBP), myosin-9 (MYH9), platelet basic protein (PPBP), platelet factor 4 (PF4), profilin-1 (PFN1), serum amyloid A-1 protein (SAA1), and thrombospondin-1 (THBS1). Following a study on a verification cohort, a panel of eight plasma protein biomarkers was identified for potential leptospirosis diagnosis: CRP, LRG1, LBP, MYH9, PPBP, PF4, SAA1, and THBS1. In conclusion, a panel of eight protein biomarkers offers a promising approach for leptospirosis diagnosis, addressing the limitations of the "one disease, one biomarker" concept.
  8. Ng TS, Desa MNM, Sandai D, Chong PP, Than LTL
    Infect Genet Evol, 2016 06;40:331-338.
    PMID: 26358577 DOI: 10.1016/j.meegid.2015.09.004
    Glucose is an important fuel source to support many living organisms. Its importance in the physiological fitness and pathogenicity of Candida glabrata, an emerging human fungal pathogen has not been extensively studied. The present study aimed to investigate the effects of glucose on the growth, biofilm formation, antifungal susceptibility and oxidative stress resistance of C. glabrata. In addition, its effect on the expression of a putative high affinity glucose sensor gene, SNF3 was also investigated. Glucose concentrations were found to exert effects on the physiological responses of C. glabrata. The growth rate of the species correlated positively to the amount of glucose. In addition, low glucose environments were found to induce C. glabrata to form biofilm and resist amphotericin B. Conversely, high glucose environments promoted oxidative stress resistance of C. glabrata. The expression of CgSNF3 was found to be significantly up-regulated in low glucose environments. The expression of SNF3 gene in clinical isolates was found to be higher compared to ATCC laboratory strains in low glucose concentrations, which may explain the better survivability of clinical isolates in the low glucose environment. These observations demonstrated the impact of glucose in directing the physiology and virulence fitness of C. glabrata through the possible modulation by SNF3 as a glucose sensor, which in turn aids the species to adapt, survive and thrive in hostile host environment.
  9. Philip N, Affendy NB, Masri SN, Yuhana MY, Than LTL, Sekawi Z, et al.
    PLoS One, 2020;15(9):e0239069.
    PMID: 32915919 DOI: 10.1371/journal.pone.0239069
    The diagnosis of leptospirosis remains a challenge due to its non-specific symptoms and the biphasic nature of the illness. A comprehensive diagnosis that includes both molecular (polymerase chain reaction (PCR)) and serology is vital for early detection of leptospirosis and to avoid misdiagnosis. However, not all samples could be subjected to both tests (serology and molecular) due to budget limitation, infrastructure, and technical expertise at least in resource-limited countries. We evaluated the usefulness of testing the clinically suspected leptospirosis cases with both techniques on all samples collected from the patients on the day of admission. Among the 165 patient's blood/serum samples tested (from three hospitals in Central Malaysia), 43 (26%) showed positivity by microscopic agglutination test (MAT), 63 (38%) by PCR, while 14 (8%) were positive by both MAT and PCR. For PCR, we tested two molecular targets (lipL32 by qPCR and 16S rDNA or rrs by nested PCR) and detected lipL32 in 47 (29%) and rrs gene in 63 (38%) patients. The use of more than one target gene for PCR increased the detection rates. Hence, a highly sensitive multiplex PCR targeting more than one diagnostic marker is recommended for the early detection of Leptospira in suspected patients. When the frequencies for positivity detected either by MAT or PCR combined, leptospirosis was diagnosed in a total of 92 (56%) patients, a higher frequency compared to when samples were only tested by a single method (MAT or PCR). The results from this study suggest the inclusion of both serology and molecular methods for every first sample irrespective of the days post-onset of symptoms (DPO) collected from patients for early diagnosis of leptospirosis.
  10. Chew SY, Ho KL, Cheah YK, Sandai D, Brown AJP, Than LTL
    Int J Mol Sci, 2019 Jun 28;20(13).
    PMID: 31261727 DOI: 10.3390/ijms20133172
    Flexibility in carbon metabolism is pivotal for the survival and propagation of many human fungal pathogens within host niches. Indeed, flexible carbon assimilation enhances pathogenicity and affects the immunogenicity of Candida albicans. Over the last decade, Candida glabrata has emerged as one of the most common and problematic causes of invasive candidiasis. Despite this, the links between carbon metabolism, fitness, and pathogenicity in C. glabrata are largely unexplored. Therefore, this study has investigated the impact of alternative carbon metabolism on the fitness and pathogenic attributes of C. glabrata. We confirm our previous observation that growth on carbon sources other than glucose, namely acetate, lactate, ethanol, or oleate, attenuates both the planktonic and biofilm growth of C. glabrata, but that biofilms are not significantly affected by growth on glycerol. We extend this by showing that C. glabrata cells grown on these alternative carbon sources undergo cell wall remodeling, which reduces the thickness of their β-glucan and chitin inner layer while increasing their outer mannan layer. Furthermore, alternative carbon sources modulated the oxidative stress resistance of C. glabrata as well as the resistance of C. glabrata to an antifungal drug. In short, key fitness and pathogenic attributes of C. glabrata are shown to be dependent on carbon source. This reaffirms the perspective that the nature of the carbon sources available within specific host niches is crucial for C. glabrata pathogenicity during infection.
  11. Fish-Low CY, Than LTL, Ling KH, Lin Q, Sekawi Z
    J Microbiol Immunol Infect, 2020 Feb;53(1):157-162.
    PMID: 31029530 DOI: 10.1016/j.jmii.2018.12.015
    BACKGROUND: Human leptospirosis, or commonly known as "rat urine disease" is a zoonotic disease that is caused by the bacteria called Leptospira sp. The incidence rate of leptospirosis has been under-reported due to its unspecific clinical symptoms and the limitations of current laboratory diagnostic methods. Leptospirosis can be effectively treated with antibiotics in the early stage, and it is a curable disease but the accuracy to diagnose the infection is rarely achieved.

    METHODS: The present pilot study investigated plasma protein profiles of leptospirosis patients and compared them against two control groups which consisted of dengue patients and healthy individuals. The plasma protein digests were analyzed using shotgun approach by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Protein abundances were estimated from the exponentially modified protein abundance index (emPAI) values. Plasma proteins in leptospirosis patients with at least two-fold differential expression compared to dengue and healthy control groups (p 

  12. Liew WP, Nurul-Adilah Z, Than LTL, Mohd-Redzwan S
    Front Microbiol, 2018;9:1503.
    PMID: 30042748 DOI: 10.3389/fmicb.2018.01503
    The use of probiotic as dietary approach to prevent exposure to food contaminant, aflatoxin B1 (AFB1) has greatly increased. Several studies found that AFB1 binding to the bacterial cell wall is strain-specific. Moreover, the interaction between AFB1 and bacterial cell wall is not well-understood, thus warrants further investigation. This research was conducted to assess the ability of Lactobacillus casei Shirota (Lcs) to bind AFB1 at different concentrations and to determine AFB1 binding efficiency of different Lcs cell components including live cell, heat-treated, and cell wall. In addition, the interaction between AFB1 and Lcs was also evaluated via scanning electron microscopy (SEM) and through an animal study. The binding of AFB1 by all Lcs cell components depends on the concentration of available AFB1. Among all Lcs cell components, the live Lcs cells exhibited the highest binding efficiency (98%) toward AFB1. Besides, the SEM micrographs showed that AFB1 induced structural changes on the bacterial cell surface and morphology including rough and irregular surface along with a curve rod-shaped. In vivo experiment revealed that Lcs is capable to neutralize the toxicity of AFB1 on body weight and intestine through the binding process. The animal's growth was stunted due to AFB1 exposure, however, such effect was significantly (p < 0.05) alleviated by Lcs. This phenomenon can be explained by a significant (p < 0.05) decreased level of blood serum AFB1 by Lcs (49.6 ± 8.05 ng/mL) compared to AFB1-exposed rats without treatment (88.12 ± 10.65 ng/mL). Taken together, this study highlights the potential use of Lcs as a preventive agent against aflatoxicosis via its strong binding capability.
  13. Lim FL, Hashim Z, Than LTL, Md Said S, Hashim JH, Norbäck D
    Int J Tuberc Lung Dis, 2019 11 01;23(11):1171-1177.
    PMID: 31718753 DOI: 10.5588/ijtld.18.0668
    OBJECTIVE: To examine the associations between endotoxin and (1,3)-β-glucan concentrations in office dust and respiratory symptoms and airway inflammation among 695 office workers in Malaysia.METHODS: Health data were collected using a questionnaire, sensitisation testing and measurement of fractional exhaled nitric oxide (FeNO). Indoor temperature, relative air humidity (RH) and carbon dioxide (CO₂) were measured in the offices and settled dust was vacuumed and analysed for endotoxin and (1,3)-β-glucan concentrations. Associations were analysed by two level multiple logistic regression.RESULTS: Overall, 9.6% of the workers had doctor-diagnosed asthma, 15.5% had wheeze, 18.4% had daytime attacks of breathlessness and 25.8% had elevated FeNO (≥25 ppb). The median levels in office dust were 11.3 EU/mg endotoxin and 62.9 ng/g (1,3)-β-glucan. After adjusting for personal and home environment factors, endotoxin concentration in dust was associated with wheeze (P = 0.02) and rhinoconjunctivitis (P = 0.007). The amount of surface dust (P = 0.04) and (1,3)-β-glucan concentration dust (P = 0.03) were associated with elevated FeNO.CONCLUSION: Endotoxin in office dust could be a risk factor for wheeze and rhinoconjunctivitis among office workers in mechanically ventilated offices in a tropical country. The amount of dust and (1,3)-β-glucan (a marker of indoor mould exposure) were associated with Th2 driven airway inflammation.
  14. Balakrishnan SN, Yamang H, Lorenz MC, Chew SY, Than LTL
    Pathogens, 2022 May 25;11(6).
    PMID: 35745472 DOI: 10.3390/pathogens11060618
    Vulvovaginal candidiasis (VVC) is a prevalent gynaecological disease characterised by vaginal wall inflammation that is caused by Candida species. VVC impacts almost three-quarters of all women throughout their reproductive years. As the vaginal mucosa is the first point of contact with microbes, vaginal epithelial cells are the first line of defence against opportunistic Candida infection by providing a physical barrier and mounting immunological responses. The mechanisms of defence against this infection are displayed through the rapid shedding of epithelial cells, the presence of pattern recognition receptors, and the release of inflammatory cytokines. The bacterial microbiota within the mucosal layer presents another form of defence mechanism within the vagina through acidic pH regulation, the release of antifungal peptides and physiological control against dysbiosis. The significant role of the microbiota in maintaining vaginal health promotes its application as one of the potential treatment modalities against VVC with the hope of alleviating the burden of VVC, especially the recurrent disease. This review discusses and summarises current progress in understanding the role of vaginal mucosa and host immunity upon infection, together with the function of vaginal microbiota in VVC.
  15. Rangasamy P, Foo HL, Yusof BNM, Chew SY, Jamil AAM, Than LTL
    PMID: 37314695 DOI: 10.1007/s12602-023-10094-2
    Lactobacilli, the most common group of bacteria found in a healthy vaginal microbiota, have been demonstrated to act as a defence against colonisation and overgrowth of vaginal pathogens. These groups of bacteria have sparked interests in incorporating them as probiotics aimed at re-establishing balance within the urogenital ecosystem. In this study, the safety characteristics of Limosilactobacillus reuteri 29B (L29B) strain were evaluated through whole genome sequencing (WGS) and animal study. Cell culture assay and 16S rDNA analysis were done to evaluate the ability of the strain to colonise and adhere to the mouse vaginal tract, and RAST analysis was performed to screen for potential genes associated with probiotic trait. The histological study on the mice organs and blood analysis of the mice showed there was no incidence of inflammation. We also found no evidence of bacterial translocation. The cell culture assay on HeLa cells showed 85% of adhesion, and there was a significant reduction of Candida strain viability in displacement assay. As for the 16S rDNA analysis, there was a significant amount of L29B colonisation of the vaginal microflora. Taken together, the intravaginal administration of L29B significantly reduced the number Enterobacteriaceae and Staphylococcaceae that were present in mouse vaginal tract. It also improved and promoted a balanced vaginal microflora environment without causing any harm or irritation to mice. Limosilactobacillus 29B (L29B) is safe to be administered intravaginally.
  16. Fish-Low CY, Balami AD, Than LTL, Ling KH, Mohd Taib N, Md Shah A, et al.
    J Infect Public Health, 2020 Feb;13(2):216-220.
    PMID: 31455598 DOI: 10.1016/j.jiph.2019.07.021
    BACKGROUND: Underestimation of leptospirosis cases is happening in many countries. The most common factor of underreporting is misdiagnosis. Considering the limitations of direct detection of pathogen and serological diagnosis for leptospirosis, clinical features and blood tests though non-specific are usually referred in making presumptive diagnosis to decide disease management.

    METHODS: In this single-centre retrospective study, comparative analysis on clinical presentations and laboratory findings was performed between confirmed leptospirosis versus non-leptospirosis cases.

    RESULTS: In multivariate logistic regression evidenced by a Hosmer-Lemeshow significance value of 0.979 and Nagelkerke R square of 0.426, the predictors of a leptospirosis case are hypocalcemia (calcium <2.10mmol/L), hypochloremia (chloride <98mmol/L), and eosinopenia (absolute eosinophil count <0.040×109/L). The proposed diagnostic scoring model has a discriminatory power with area under the curve (AUC) 0.761 (p<0.001). A score value of 6 reflected a sensitivity of 0.762, specificity of 0.655, a positive predictive value of 0.38, negative predictive value of 0.91, a positive likelihood ratios of 2.21, and a negative likelihood ratios of 0.36.

    CONCLUSION: With further validation in clinical settings, implementation of this diagnostic scoring model is helpful to manage presumed leptospirosis especially in the absence of leptospirosis confirmatory tests.

  17. Isa KNM, Jalaludin J, Elias SM, Than LTL, Jabbar MA, Saudi ASM, et al.
    Ecotoxicol Environ Saf, 2021 Sep 15;221:112430.
    PMID: 34147866 DOI: 10.1016/j.ecoenv.2021.112430
    The exposure of school children to indoor air pollutants has increased allergy and respiratory diseases. The objective of this study were to determine the toxicodynamic interaction of indoor pollutants exposure, biological and chemical with expression of adhesion molecules on eosinophil and neutrophil. A self-administered questionnaire, allergy skin test, and fractional exhaled nitric oxide (FeNO) analyser were used to collect information on health status, sensitization to allergens and respiratory inflammation, respectively among school children at age of 14 years. The sputum induced were analysed to determine the expression of CD11b, CD35, CD63 and CD66b on eosinophil and neutrophil by using flow cytometry technique. The particulate matter (PM2.5 and PM10), NO2, CO2, and formaldehyde, temperature, and relative humidity were measured inside the classrooms. The fungal DNA were extracted from settled dust collected from classrooms and evaluated using metagenomic techniques. We applied chemometric and regression in statistical analysis. A total of 1869 unique of operational taxonomic units (OTUs) of fungi were identified with dominated at genus level by Aspergillus (15.8%), Verrucoconiothyrium (5.5%), and Ganoderma (4.6%). Chemometric and regression results revealed that relative abundance of T. asahii were associated with down regulation of CD66b expressed on eosinophil, and elevation of FeNO levels in predicting asthmatic children with model accuracy of 63.6%. Meanwhile, upregulation of CD11b expressed on eosinophil were associated with relative abundance of A. clavatus and regulated by PM2.5. There were significant association of P. bandonii with upregulation of CD63 expressed on neutrophil and exposure to NO2. Our findings indicate that exposure to PM2.5, NO2, T. asahii, P.bandonii and A.clavatus are likely interrelated with upregulation of activation and degranulation markers on both eosinophil and neutrophil.
  18. Chew SY, Brown AJP, Lau BYC, Cheah YK, Ho KL, Sandai D, et al.
    J Biomed Sci, 2021 Jan 02;28(1):1.
    PMID: 33388061 DOI: 10.1186/s12929-020-00700-8
    BACKGROUND: Emergence of Candida glabrata, which causes potential life-threatening invasive candidiasis, has been widely associated with high morbidity and mortality. In order to cause disease in vivo, a robust and highly efficient metabolic adaptation is crucial for the survival of this fungal pathogen in human host. In fact, reprogramming of the carbon metabolism is believed to be indispensable for phagocytosed C. glabrata within glucose deprivation condition during infection.

    METHODS: In this study, the metabolic responses of C. glabrata under acetate growth condition was explored using high-throughput transcriptomic and proteomic approaches.

    RESULTS: Collectively, a total of 1482 transcripts (26.96%) and 242 proteins (24.69%) were significantly up- or down-regulated. Both transcriptome and proteome data revealed that the regulation of alternative carbon metabolism in C. glabrata resembled other fungal pathogens such as Candida albicans and Cryptococcus neoformans, with up-regulation of many proteins and transcripts from the glyoxylate cycle and gluconeogenesis, namely isocitrate lyase (ICL1), malate synthase (MLS1), phosphoenolpyruvate carboxykinase (PCK1) and fructose 1,6-biphosphatase (FBP1). In the absence of glucose, C. glabrata shifted its metabolism from glucose catabolism to anabolism of glucose intermediates from the available carbon source. This observation essentially suggests that the glyoxylate cycle and gluconeogenesis are potentially critical for the survival of phagocytosed C. glabrata within the glucose-deficient macrophages.

    CONCLUSION: Here, we presented the first global metabolic responses of C. glabrata to alternative carbon source using transcriptomic and proteomic approaches. These findings implicated that reprogramming of the alternative carbon metabolism during glucose deprivation could enhance the survival and persistence of C. glabrata within the host.

  19. Chew SY, Ho KL, Cheah YK, Ng TS, Sandai D, Brown AJP, et al.
    Sci Rep, 2019 02 26;9(1):2843.
    PMID: 30808979 DOI: 10.1038/s41598-019-39117-1
    The human fungal pathogen Candida glabrata appears to utilise unique stealth, evasion and persistence strategies in subverting the onslaught of host immune response during systemic infection. However, macrophages actively deprive the intracellular fungal pathogen of glucose, and therefore alternative carbon sources probably support the growth and survival of engulfed C. glabrata. The present study aimed to investigate the role of the glyoxylate cycle gene ICL1 in alternative carbon utilisation and its importance for the virulence of C. glabrata. The data showed that disruption of ICL1 rendered C. glabrata unable to utilise acetate, ethanol or oleic acid. In addition, C. glabrata icl1∆ cells displayed significantly reduced biofilm growth in the presence of several alternative carbon sources. It was also found that ICL1 is crucial for the survival of C. glabrata in response to macrophage engulfment. Disruption of ICL1 also conferred a severe attenuation in the virulence of C. glabrata in the mouse model of invasive candidiasis. In conclusion, a functional glyoxylate cycle is essential for C. glabrata to utilise certain alternative carbon sources in vitro and to display full virulence in vivo. This reinforces the view that antifungal drugs that target fungal Icl1 have potential for future therapeutic intervention.
  20. Wan Yusoff WSY, Abdullah M, Sekawi Z, Amran F, Yuhana MY, Mohd Taib N, et al.
    Eur J Clin Microbiol Infect Dis, 2019 Dec;38(12):2349-2353.
    PMID: 31529307 DOI: 10.1007/s10096-019-03699-5
    Clinical manifestations of leptospirosis range from mild, common cold-like illness, to a life-threatening condition. The host immune response has been hypothesized to play a major role in leptospirosis outcome. Increased levels of inflammatory mediators, such as cytokines, may promote tissue damage that lead to increased disease severity. The question is whether cytokines levels may predict the outcome of leptospirosis and guide patient management. This study aimed to assess the association between Th1-, Th2-, and Th17-related cytokines with the clinical outcome of patients with leptospirosis. Different cytokine levels were measured in fifty-two plasma samples of hospitalized patients diagnosed with leptospirosis in Malaysia (January 2016-December 2017). Patients were divided into two separate categories: survived (n = 40) and fatal outcome (n = 12). Nineteen plasma samples from healthy individuals were obtained as controls. Cytokine quantification was performed using Simple Plex™ assays from ProteinSimple (San Jose, CA, USA). Measurements were done in triplicate and statistical analysis was performed using GraphPad software and SPSS v20. IL-6 (p = 0.033), IL-17A (p = 0.022), and IL-22 (p = 0.046) were significantly elevated in fatal cases. IL-17A concentration (OR 1.115; 95% CI 1.010-1.231) appeared to be an independent predictor of fatality of leptospirosis. Significantly higher levels of TNF-α (p ≤ 0.0001), IL-6 (p ≤ 0.0001), IL-10 (p ≤ 0.0001), IL-12 (p ≤ 0.0001), IL17A (p ≤ 0.0001), and IL-18 (p ≤ 0.0001) were observed among leptospirosis patients in comparison with healthy controls. Our study shows that certain cytokine levels may serve as possible prognostic biomarkers in leptospirosis patients.
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