Displaying publications 1 - 20 of 113 in total

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  1. Zainuddin NH, Chee HY, Ahmad MZ, Mahdi MA, Abu Bakar MH, Yaacob MH
    J Biophotonics, 2018 08;11(8):e201700363.
    PMID: 29570957 DOI: 10.1002/jbio.201700363
    This paper presents the development of tapered optical fiber sensor to detect a specific Leptospira bacteria DNA. The bacteria causes Leptospirosis, a deadly disease but with common early flu-like symptoms. Optical single mode fiber (SMF) of 125 μm diameter is tapered to produce 12 μm waist diameter and 15 cm length. The novel DNA-based optical fiber sensor is functionalized by incubating the tapered region with sodium hydroxide (NaOH), (3-Aminopropyl) triethoxysilane and glutaraldehyde. Probe DNA is immobilized onto the tapered region and subsequently hybridized by its complementary DNA (cDNA). The transmission spectra of the DNA-based optical fiber sensor are measured in the 1500 to 1600 nm wavelength range. It is discovered that the shift of the wavelength in the SMF sensor is linearly proportional with the increase in the cDNA concentrations from 0.1 to 1.0 nM. The sensitivity of the sensor toward DNA is measured to be 1.2862 nm/nM and able to detect as low as 0.1 fM. The sensor indicates high specificity when only minimal shift is detected for non-cDNA testing. The developed sensor is able to distinguish between actual DNA of Leptospira serovars (Canicola and Copenhageni) against Clostridium difficile (control sample) at very low (femtomolar) target concentrations.
    Matched MeSH terms: Leptospira/genetics*
  2. Yuszniahyati Y, Kenneth FR, Daisy Vanitha J
    Med J Malaysia, 2015 Dec;70(6):351-5.
    PMID: 26988208
    OBJECTIVE: The aim of this article was to review published research articles on leptospirosis, in particular the recent incidence of leptospirosis in Malaysia and the currently available diagnostic methods for the detection of leptospirosis.

    METHODS: PubMed, Google Scholar and Google Search databases were searched using the key words Leptospira and leptospirosis. A total of seventy-six references were reviewed including sixty-seven research articles, three annual reports from Ministry of Health and six online newspaper articles. This review includes the following five sub-headings: introduction, leptospirosis transmission, leptospirosis incidents, laboratory diagnosis of leptospirosis and treatment and prevention of leptospirosis.

    RESULTS: An increase in incidents of leptospirosis cases has been seen in recent years in Malaysia. The recent floods have contributed to the rise in the number of reported cases. Current diagnostic approaches such as dark field microscopy, microscopic agglutination test (MAT), Polymerase chain reaction and serological tests are inadequate as the organism is a slow grower.

    CONCLUSION: There is an urgent need to develop newer techniques for rapid detection of leptospirosis. The combination of PCR and ELISA are suggested for rapid and accurate diagnosis of leptospirosis. Studies on the mechanism of pathogenesis of Leptospira are needed for the development of vaccines that are safe for human use.
    Matched MeSH terms: Leptospira
  3. Yusof NY, Muhammad Yusoff F, Muhammad Harish S, Ahmad MN, Khalid MF, Mohd Nor F, et al.
    Microbiol Resour Announc, 2019 Jul 11;8(28).
    PMID: 31296668 DOI: 10.1128/MRA.00015-19
    The Gram-negative pathogenic spirochetal bacteria Leptospira spp. cause leptospirosis in humans and livestock animals. Leptospira kmetyi strain LS 001/16 was isolated from a soil sample associated with a leptospirosis patient in Kelantan, which is among the states in Malaysia with a high reported number of disease cases. Here, we report the complete genome sequence of Leptospira kmetyi strain LS 001/16.
    Matched MeSH terms: Leptospira
  4. Yeoh, S.Y., Anhar, H.S., Chua, S.M., Raja, N.R.O., Nor, F.A.J., Azida, J.W.A.K.
    Medicine & Health, 2018;13(1):272-278.
    MyJurnal
    Diagnosis of ocular leptospirosis is challenging and requires a high index of suspicion of previous leptospiral infection and good laboratory support. This case series focuses on two young females with unilateral conjunctiva granuloma. To the best of our knowledge, these are the first two cases of ocular leptospirosis with conjunctiva granuloma. The definitive diagnosis of ocular leptospirosis was based on laboratory studies in which conjunctival biopsies in these two cases showed positive leptospira DNA. Retrospectively, the history was suggestive as both patients had exposure to leptospira organism. In conclusion, a diagnosis of ocular leptospirosis requires a high clinical suspicion index supported by mandatory laboratory investigations.
    Matched MeSH terms: Leptospira
  5. Yeoh TS, Tang TH, Citartan M
    Biotechnol J, 2023 Mar;18(3):e2200418.
    PMID: 36426669 DOI: 10.1002/biot.202200418
    Leptospirosis is a potentially life-threatening zoonosis caused by pathogenic Leptospira and for rapid diagnostics, direct detection is desirable. LipL32 protein is the most suitable biomarker for direct detection. DNA aptamers are sought to be generated against LipL32 by Systemic Evolution of Ligands via Exponential Enrichment (SELEX). LepDapt-5a is the most potent aptamer candidate among all the candidates, as determined by direct Enzyme-linked Aptasorbent Assay (ELASA). LepDapt-5a was predicted to form a G-quadruplex structure as predicted by QGRS Mapper and validated experimentally by direct ELASA. The diagnostic potential of the aptamer was further tested on a direct and sandwich ELASA platform. A LOD of 106 mL-1 and 105 mL-1 were estimated by direct and sandwich ELASA platforms, respectively, which are within the range associated with leptospiremia levels. The dot blot assay developed was able to attain a LOD of 104 CFU mL-1 against pathogenic Leptospira, which is also within the leptospiremia level. This is the first-ever DNA aptamer and hybrid-heterodimeric aptamer constructed against LipL32. The diagnostic potentiality of the LepDapt-5a DNA aptamer was proven on three major diagnostic platforms, which are direct ELASA, sandwich ELASA, and aptamer-based dot assay.
    Matched MeSH terms: Leptospira/isolation & purification
  6. Yaakob Y, Rodrigues KF, Opook F, William T, John DV
    Malays J Med Sci, 2017 Oct;24(5):44-51.
    PMID: 29386971 DOI: 10.21315/mjms2017.24.5.5
    Background: Synthetic biology is emerging as a viable alternative for the production of recombinant antigens for diagnostic applications. It offers a safe alternative for the synthesis of antigenic principles derived from organisms that pose a high biological risk.

    Methods: Here, we describe an enzyme-linked immunosorbent assay (ELISA) using the synthetic recombinant LipL32 (rLipL32) protein expressed in Escherichia coli for the detection of Leptospira-specific antibodies in human serum samples. The rLipL32-based ELISA was compared with a microscopic agglutination test (MAT), which is currently used as the gold standard for the diagnosis of leptospirosis.

    Results: Our results showed that all the MAT-positive serum samples were positive for Leptospira-specific IgG in an ELISA, while 65% (n = 13) of these samples were also positive for Leptospira-specific IgM. In the MAT-negative serum samples, 80% and 55% of the samples were detected as negative by an ELISA for Leptospira-specific IgM and IgG, respectively.

    Conclusion: An ELISA using the synthetic rLipL32 antigen was able to distinguish Leptospira-specific IgM (sensitivity 65% and specificity 80%) and IgG (sensitivity 100% and specificity 55%) in human serum samples and has the potential to serve as a rapid diagnostic test for leptospirosis.

    Matched MeSH terms: Leptospira
  7. Wan Shahriman Yushdie Wan Yusoff, Maha Abdullah, Fairuz Amran, Zamberi Sekawi, Muhammad Yazli Yuhana, Syafinaz Amin Nordin
    MyJurnal
    Introduction: Leptospirosis is a re-emerging zoonotic disease caused by Leptospira bacteria. The clinical manifes-tations of leptospirosis include mild-fever to a severe or even fatal. Increased levels of inflammatory cytokines pro-duced in response to the Leptospira infection by the host immune system were hypothesized as among the causes of severity in leptospirosis. Besides the classical presentation with the triad of febrile, jaundice, and renal failure, patients with leptospirosis also can pose with predominant sign and symptoms of pulmonary involvement. This study aimed to compare the levels of TNF-α, IL-1b, IL-4, IL-6, IL-8, IL-10, IL-12, IL-13, IL-17A, IL-18, and IL-22 In the plasma of samples of leptospirosis patients with and without pneumonia. Methods: Circulating cytokine levels in plasma were measured in seventeen patients hospitalized and diagnosed with leptospirosis in Malaysia (January 2016 – December 2017) and nineteen healthy individuals as controls. Patients were categorized into leptospirosis without pneumonia (n=12) and with pneumonia (n=5). Cytokine was measured using SimplePlexTM assays (San Jose, CA, USA). Measurement was performed in triplicate and statistical analysis was conducted using Graphpad® Prism v6 (San Diego, CA, USA). Results: Elevation of plasma TNF-α, IL-6, IL-8, IL-10, IL-18, and IL-22 levels were observed among leptospirosis patients with pneumonia compared to without, although no statistical differences were observed between these two groups. Conclusion: There are no significant differences observed between the levels of plasma TNF-α, IL-6, IL-8, IL-10, IL-18, and IL-22 in patients with pneumonia compared to without.
    Matched MeSH terms: Leptospira
  8. Vk C, Ty L, Wf L, Ywy WS, An S, S Z, et al.
    Microbiol Res, 2018 Mar;207:108-115.
    PMID: 29458845 DOI: 10.1016/j.micres.2017.11.015
    Leptospirosis remains one of the most widespread zoonotic diseases caused by spirochetes of the genus Leptospira, which accounts for high morbidity and mortality globally. Leptospiral infections are often found in tropical and subtropical regions, with people exposed to contaminated environments or animal reservoirs are at high risk of getting the infection. Leptospirosis has a wide range of clinical manifestations with non-specific signs and symptoms and often misdiagnosed with other acute febrile illnesses at early stage of infection. Despite being one of the leading causes of zoonotic morbidity worldwide, there is still a gap between pathogenesis and human immune responses during leptospiral infection. It still remains obscure whether the severity of the infection is caused by the pathogenic properties of the Leptospira itself, or it is a consequence of imbalance host immune factors. Hence, in this review, we seek to summarize the past and present milestone findings on the biomarkers of host immune response aspects during human leptospiral infection, including cytokine and other immune mediators. A profound understanding of the interlink between virulence factors and host immune responses during human leptospirosis is imperative to identify potential biomarkers for diagnostic and prognostic applications as well as designing novel immunotherapeutic strategies in future.
    Matched MeSH terms: Leptospira/immunology*; Leptospira/pathogenicity
  9. Vincent AT, Schiettekatte O, Goarant C, Neela VK, Bernet E, Thibeaux R, et al.
    PLoS Negl Trop Dis, 2019 05;13(5):e0007270.
    PMID: 31120895 DOI: 10.1371/journal.pntd.0007270
    The causative agents of leptospirosis are responsible for an emerging zoonotic disease worldwide. One of the major routes of transmission for leptospirosis is the natural environment contaminated with the urine of a wide range of reservoir animals. Soils and surface waters also host a high diversity of non-pathogenic Leptospira and species for which the virulence status is not clearly established. The genus Leptospira is currently divided into 35 species classified into three phylogenetic clusters, which supposedly correlate with the virulence of the bacteria. In this study, a total of 90 Leptospira strains isolated from different environments worldwide including Japan, Malaysia, New Caledonia, Algeria, mainland France, and the island of Mayotte in the Indian Ocean were sequenced. A comparison of average nucleotide identity (ANI) values of genomes of the 90 isolates and representative genomes of known species revealed 30 new Leptospira species. These data also supported the existence of two clades and 4 subclades. To avoid classification that strongly implies assumption on the virulence status of the lineages, we called them P1, P2, S1, S2. One of these subclades has not yet been described and is composed of Leptospira idonii and 4 novel species that are phylogenetically related to the saprophytes. We then investigated genome diversity and evolutionary relationships among members of the genus Leptospira by studying the pangenome and core gene sets. Our data enable the identification of genome features, genes and domains that are important for each subclade, thereby laying the foundation for refining the classification of this complex bacterial genus. We also shed light on atypical genomic features of a group of species that includes the species often associated with human infection, suggesting a specific and ongoing evolution of this group of species that will require more attention. In conclusion, we have uncovered a massive species diversity and revealed a novel subclade in environmental samples collected worldwide and we have redefined the classification of species in the genus. The implication of several new potentially infectious Leptospira species for human and animal health remains to be determined but our data also provide new insights into the emergence of virulence in the pathogenic species.
    Matched MeSH terms: Leptospira/classification*; Leptospira/genetics; Leptospira/isolation & purification; Leptospira/pathogenicity*
  10. Triassi AJ, Wheatley MS, Savka MA, Gan HM, Dobson RC, Hudson AO
    Front Microbiol, 2014;5:509.
    PMID: 25309529 DOI: 10.3389/fmicb.2014.00509
    Despite the urgent need for sustained development of novel antibacterial compounds to combat the drastic rise in antibiotic resistant and emerging bacterial infections, only a few clinically relevant antibacterial drugs have been recently developed. One of the bottlenecks impeding the development of novel antibacterial compounds is the identification of new enzymatic targets. The nutritionally essential amino acid anabolic pathways, for example lysine biosynthesis, provide an opportunity to explore the development of antibacterial compounds, since human genomes do not possess the genes necessary to synthesize these amino acids de novo. The diaminopimelate (DAP)/lysine (lys) anabolic pathways are attractive targets for antibacterial development since the penultimate lys precursor meso-DAP (m-DAP) is a cross-linking amino acid in the peptidoglycan (PG) cell wall of most Gram-negative bacteria and lys plays a similar role in the PG of most Gram-positive bacteria, in addition to its role as one of the 20 proteogenic amino acids. The L,L-diaminopimelate aminotransferase (DapL) pathway was recently identified as a novel variant of the DAP/lys anabolic pathways. The DapL pathway has been identified in the pathogenic bacteria belonging to the genus; Chlamydia, Leptospira, and Treponema. The dapL gene has been identified in the genomes of 381 or approximately 13% of the 2771 bacteria that have been sequenced, annotated and reposited in the NCBI database, as of May 23, 2014. The narrow distribution of the DapL pathway in the bacterial domain provides an opportunity for the development and or discovery of narrow spectrum antibacterial compounds.
    Matched MeSH terms: Leptospira
  11. Tan XT, Amran F, Chee Cheong K, Ahmad N
    BMC Infect Dis, 2014;14:563.
    PMID: 25338815 DOI: 10.1186/s12879-014-0563-7
    Leptospirosis is a zoonotic disease caused by Leptospira species and is distributed globally. Microscopic agglutination test (MAT) is the serological 'gold standard' for diagnosis of leptospirosis but it is time-consuming and labour-intensive. An alternative serological method that is rapid, sensitive and specific is important for early treatment to reduce morbidity and mortality. The use of local Leptospira isolation may improve the sensitivity and specificity of the test because it may varies from one geographical region to another region. The objective of this study was to determine the sensitivity, specificity and cut-off points for an in-house Immunoglobulin M (IgM) enzyme-linked immunosorbent assay (ELISA) using a locally isolated Leptospiral strain IMR/175 as the antigen for the detection of anti-Leptospiral IgM.
    Matched MeSH terms: Leptospira/isolation & purification
  12. Tan TL, Lee LY, Lim WC
    Med J Malaysia, 2018 12;73(6):427-429.
    PMID: 30647223
    The occurrence of Leptospirosis and Escherichia coli coinfection in the post-partum period is a novel case. This report illustrated a previously well woman from a suburban area presented with acute neurological deterioration following a two days history of fever during her puerperal period. Early interventions with fluids, broad spectrum antibiotics and intensive supportive care were given. Despite that, she deteriorated rapidly and developed pulmonary hemorrhage, disseminated intravascular coagulopathy, and multi-organ failure. She succumbed within 12 hours of admission. The knowledge about such fatal co-infections should be disseminated to medical practitioners encountering Leptospirosis infection and general public.
    Matched MeSH terms: Leptospira
  13. Tan DS
    Bull World Health Organ, 1969;40(6):899-902.
    PMID: 5307602
    Epidemiological studies of human leptospirosis have generally been limited to countries with specialized laboratories employing the microscopic-agglutination (MA) test. The sensitized-erythrocyte-lysis (SEL) test is much simpler for routine hospital laboratories to carry out and it has been found valuable in the diagnosis of human leptospirosis. This paper reports the results of studies of the SEL test as an epidemiological tool in serological surveys.The results showed that the significant SEL titre was 1:80 and that the sensitivity of the test depended possibly on the antigen preparation and the amount of complement used. Most of the SEL antibodies were found to persist at significant titres for about 1 year after active infection, but less than half persisted longer than that. The SEL test is therefore useful for detecting recent infections and for indicating that stability of leptospirosis in an area.The endemicity of leptospirosis in West Malaysia was confirmed by the SEL test, based on the employment of 1:80 as the significant titre.
    Matched MeSH terms: Leptospira/immunology
  14. Suut L, Mazlan MN, Arif MT, Yusoff H, Abdul Rahim NA, Safii R, et al.
    Asia Pac J Public Health, 2016 07;28(5):450-7.
    PMID: 27183976 DOI: 10.1177/1010539516648003
    Leptospirosis is an important zoonotic disease globally and is endemic in Malaysia. A study was conducted in the Rejang basin of Sarawak from June 2011 to May 2013 to determine the seroprevalence of leptospirosis among the communities and dominant infecting Leptospira serovars. A total of 508 human sera were analyzed using ELISA and the microscopic agglutination test (MAT). The seroprevalence of leptospirosis in the study area was 37.4%, with the highest prevalence in Kapit division. More women were positive for leptospirosis (59.5%), and the mean age of seropositive individuals was 42.2 (SD = 18.7) years. Antibody titers between 1:50 and 1:1600 were reported, and serovars djasiman (22.1%), shermani (13.2%), and pomona (7.9%) predominated, with varied distribution between geographical locations. This study highlighted the endemicity and diversity of existing Leptospira serovars within the community. This information should be communicated to local health personnel and communities at risk, and rapid diagnostic capability should be made available to local health facilities.
    Matched MeSH terms: Leptospira/genetics; Leptospira/immunology; Leptospira/isolation & purification*
  15. Suppiah J, Chan SY, Ng MW, Khaw YS, Ching SM, Mat-Nor LA, et al.
    J Biomed Sci, 2017 Jun 28;24(1):40.
    PMID: 28659189 DOI: 10.1186/s12929-017-0344-x
    BACKGROUND: Dengue and leptospirosis infections are currently two major endemics in Malaysia. Owing to the overlapping clinical symptoms between both the diseases, frequent misdiagnosis and confusion of treatment occurs. As a solution, the present work initiated a pilot study to investigate the incidence related to co-infection of leptospirosis among dengue patients. This enables the identification of more parameters to predict the occurrence of co-infection.

    METHOD: Two hundred sixty eight serum specimens collected from patients that were diagnosed for dengue fever were confirmed for dengue virus serotyping by real-time polymerase chain reaction. Clinical, laboratory and demographic data were extracted from the hospital database to identify patients with confirmed leptospirosis infection among the dengue patients. Thus, frequency of co-infection was calculated and association of the dataset with dengue-leptospirosis co-infection was statistically determined.

    RESULTS: The frequency of dengue co-infection with leptospirosis was 4.1%. Male has higher preponderance of developing the co-infection and end result of shock as clinical symptom is more likely present among co-infected cases. It is also noteworthy that, DENV 1 is the common dengue serotype among all cases identified as dengue-leptospirosis co-infection in this study.

    CONCLUSION: The increasing incidence of leptospirosis among dengue infected patients has posed the need to precisely identify the presence of co-infection for the betterment of treatment without mistakenly ruling out either one of them. Thus, anticipating the possible clinical symptoms and laboratory results of dengue-leptospirosis co-infection is essential.

    Matched MeSH terms: Leptospira/isolation & purification
  16. Smith CE, Turner LH
    Bull World Health Organ, 1961;24(1):35-43.
    PMID: 20604084
    One of the factors on which the incidence of leptospirosis is dependent is the survival time of shed leptospires in surface water or soil water, and this time is in turn affected by the acidity or alkalinity of the water. The authors have therefore studied the survival of four leptospiral serotypes in buffered distilled water at pH's ranging from 5.3 to 8.0. All survived longer in alkaline than in acid water, and significant differences between the serotypes were found in response to pH. Survival at pH's under 7.0 ranged from 10 to 117 days and at pH's over 7.0 from 21 to 152 days. Survival was also studied in aqueous extracts of soil samples from different areas in Malaya; no correlation was found between pH and survival time.It was also noted that in a group of Malayan ricefields a low incidence of leptospirosis in man was accompanied by a high infection rate among rodents, and when it was found that this phenomenon could not be explained by pH or salinity, attention was turned to the soil. Bentonite clay, similar to the montmorrillonite clay of the ricefields, was found to adsorb about half the leptospires in suspension. The authors recommend that field study of this laboratory observation be undertaken.
    Matched MeSH terms: Leptospira
  17. Slack AT, Khairani-Bejo S, Symonds ML, Dohnt MF, Galloway RL, Steigerwalt AG, et al.
    Int J Syst Evol Microbiol, 2009 Apr;59(Pt 4):705-8.
    PMID: 19329592 DOI: 10.1099/ijs.0.002766-0
    A single Leptospira strain (designated Bejo-Iso9(T)) was isolated from a soil sample taken in Johor, Malaysia. The isolate showed motility and morphology typical of the genus Leptospira under dark-field microscopy. Cells were found to be 10-13 microm in length and 0.2 microm in diameter, with a wavelength of 0.5 microm and an amplitude of approximately 0.2 microm. Phenotypically, strain Bejo-Iso9(T) grew in Ellinghausen-McCullough-Johnson-Harris medium at 13, 30 and 37 degrees C, and also in the presence of 8-azaguanine. Serologically, strain Bejo-Iso9(T) produced titres towards several members of the Tarassovi serogroup, but was found to be serologically unique by cross-agglutinin absorption test and thus represented a novel serovar. The proposed name for this serovar is Malaysia. Phylogenetic analysis of 16S rRNA gene sequences placed this novel strain within the radiation of the genus Leptospira, with sequence similarities within the range 90.4-99.5% with respect to recognized Leptospira species. DNA-DNA hybridization against the three most closely related Leptospira species was used to confirm the results of the 16S rRNA gene sequence analysis. The G+C content of the genome of strain Bejo-Iso9(T) was 36.2 mol%. On the basis of phenotypic, serological and phylogenetic data, strain Bejo-Iso9(T) represents a novel species of the genus Leptospira, for which the name Leptospira kmetyi sp. nov. is proposed. The type strain is Bejo-Iso9(T) (=WHO LT1101(T)=KIT Bejo-Iso9(T)).
    Matched MeSH terms: Leptospira/classification*; Leptospira/genetics; Leptospira/isolation & purification*; Leptospira/physiology
  18. Siti-Nurdyana, A.K., Bahaman, A.R., Sharma, R.S.K., Azlan, C.M., Abdul Razak, M.F.A.
    Jurnal Veterinar Malaysia, 2016;28(2):1-3.
    MyJurnal
    Leptospirosis is recognised as one of the leading zoonotic diseases and rodents have been implicated as one of the natural reservoirs of the disease. The Malayan porcupines (Hystrix brachyura) which are also a rodent could possibly be a carrier of leptospiral organisms. This study was conducted to determine the serological prevalence of leptospiral infection among captive Malayan porcupines and to disclose the possibility of porcupines as a reservoir for leptospiral infection. Fifty serum samples were obtained from the Malayan porcupines kept in captivity at the Wildlife Conservation Centre, Sungai Dusun, Malaysia. The microscopic agglutination test (MAT) was performed on the serum samples to detect the presence of agglutinating antibodies to a panel of 16 Leptospira serovars (Australis, Autumnalis, Ballum, Bataviae, Canicola, Celledoni, Djasiman, Hardjobovis, Hardjopratjino, Hebdomadis, Hurstbridge, Icterohaemorrhagiae, Javanica, Pomona, Pyrogenes and Sejroe). From the serological test, 18% (n=9/50) of the Malayan porcupines tested had leptospiral antibodies to serovars Javanica (8%), Hurstbridge (4%), Ballum (2%), Celledoni (2%) and Hardjoprajitno (2%). It is seen that this study disclosed a high prevalence of leptospiral infection in the Malayan porcupines tested and indicated that the Malayan porcupines could possibly be a source of leptospirosis to other animals including humans and that they might play an important role in the epidemiology of leptospiral infection in the country.
    Matched MeSH terms: Leptospira
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