Displaying publications 81 - 100 of 199 in total

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  1. Overview of the distribution of Burkholderia pseudomallei Sequence Types and the Emergence of Sequence Type 1342 in Malaysia
    Teh CSJ, Yap PSX, Zulkefli NJ, Subramaniam P, Sit PS, Kong ZX, et al.
    Transbound Emerg Dis, 2021 Jan 27.
    PMID: 33506647 DOI: 10.1111/tbed.14005
    Burkholderia pseudomallei, a Gram-negative bacterial pathogen that causes melioidosis, is of public health importance in endemic areas including Malaysia. An investigation of the molecular epidemiology links of B. pseudomallei would contribute to better understanding of the clonal relationships, transmission dynamics and evolutionary change. Multi-locus sequence typing (MLST) of 45 clinical B. pseudomallei isolates collected from sporadic meliodosis cases in Malaysia was performed. In addition, a total of 449 B. pseudomallei Malaysian strains submitted to the MLST database from 1964 until 2019 were included in the temporal analysis to determine the endemic sequence types (STs), emergence and re-emergence of ST(s). In addition, strain-specific distribution was evaluated using BURST tool. Genotyping of 45 clinical strains were resolved into 12 STs and the majority were affiliated with ST46 (n=11) and ST1342 (n=7). Concomitantly, ST46 was the most prevalent ST in Malaysia which first reported in 1964. All the Malaysian B. pseudomallei strains were resolved into 76 different STs with 36 of them uniquely present only in Malaysia. ST1342 was most closely related to ST1034, in which both STs were unique to Malaysia and first isolated from soil samples in Pahang, a state in Malaysia. The present study revealed a high diversity of B. pseudomallei in Malaysia. Localised evolution giving rise to the emergence of new STs was observed, suggesting that host and environmental factors play a crucial role in the evolutionary changes of B. pseudomallei.
    Matched MeSH terms: Burkholderia pseudomallei
  2. Reduced susceptibility of Burkholderia pseudomallei following exposure to carbapenem
    Zamani A, Zueter AR, Muhd Besari A, Hasan H, Harun A, Deris ZZ
    Trop Biomed, 2020 Sep 01;37(3):783-790.
    PMID: 33612791 DOI: 10.47665/tb.37.3.783
    Reduced susceptibility in Burkholderia pseudomallei during carbapenem therapy may lead to treatment failure. We isolated a clinical strain that had developed reduced susceptibility to carbapenems while on treatment. After reviewing the patient's clinical notes, the initial isolate (BUPS01/14) was exposed to carbapenem in vitro to mimic the clinical scenario. The stability of susceptibility of the carbapenem-exposed strain (BUPS01/14R) was examined by serial subculture in antibiotic-free broth. Biochemical and morphological comparison was performed by the VITEK® system and electron microscopy. MICs increased 32-fold following carbapenem exposure and became stable in the antibiotic-free environment. On electron microscopic examination, the BUPS01/14R cells were smoother and less wrinkled compared to BUPS01/14 cells. This report highlights a potential anti-melioidosis treatment failure due to the emergence of resistance while on carbapenem monotherapy. Further study of this strain is necessary to understand the mechanism of resistance at a molecular level.
    Matched MeSH terms: Burkholderia pseudomallei
  3. Fulltext Paravertebral Abscess Caused By Bukholderia Pseudomallei In
    Ahmad, S., Azura, L., Duski, S., Aziz, M.Y.
    Malays Orthop J, 2009;3(1):88-90.
    MyJurnal
    A 53-year-old Malay man was admitted with intestinal obstruction, fever and lower limb weakness. Initial clinical impression was myelitis causing paralytic ilues and paraperesis. Blood culture showed Burkholderia pseudomallei infection and subsequent MRI showed paravertebral abscess. This case highlights a rare manifestation of melioidosis involving the spine and difficulties in establishing the diagnosis.

    Matched MeSH terms: Burkholderia pseudomallei
  4. Fulltext Expression and purification of soluble recombinant GST-Tagged BPSL2774 protein from Burkholderia Pseudomallei K96243
    Aisyah Mohamed Rehan, Hanisah Ujang, Siti Marhamah Drahaman, Nor Azurah Mat Akhir, Noraslinda Muhamad Bunnor, Mohd Firdaus Raih
    International Medical Journal Malaysia, 2017;16(11):33-33.
    MyJurnal
    Burkholderia pseudomallei is the causative agent of melioidosis, an
    infectious disease endemic in Southeast Asia and northern Australia. Cases have been
    reported in Pahang, Johor Bahru and Kedah. The disease is difficult to combat as B.
    pseudomallei has shown resistance to various antibiotics and much is still not understood
    about its pathogenicity. It is suggested that investigating the bacterium hypothetical
    proteins may provide potential new targets for the development of antimicrobials. The
    gene of interest in this study, BPSL2774, encoding BPSL2774 hypothetical protein, is a
    target gene that was predicted as essential using transposon-directed insertion site
    sequencing technique (TraDIS). We aimed to express and purify soluble GST-tagged
    BPSL2774 protein at sufficient concentration for future functional assays. (Copied from article).
    Matched MeSH terms: Burkholderia pseudomallei
  5. Fulltext Relapse of chronic melioidosis in a paediatric cystic fibrosis patient: first case report from Malaysia
    Mariappan V, Thavagnanam S, Vellasamy KM, Teh CJS, Atiya N, Ponnampalavanar S, et al.
    BMC Infect Dis, 2018 Sep 05;18(1):455.
    PMID: 30185168 DOI: 10.1186/s12879-018-3371-7
    BACKGROUND: Burkholderia pseudomallei is the causative agent of melioidosis, which is a potentially life threatening disease endemic in Southeast Asian countries. In Malaysia, cystic fibrosis (CF) is an uncommon condition. The association between CF and B.pseudomallei infections has been reported previously. However, this is the first case report of a pediatric melioidosis relapse and co-infection with other Gram-negative bacteria in Malaysia.

    CASE PRESENTATION: A 14-year-old Chinese Malaysian boy presented with a history of recurrent pneumonia, poor growth and steatorrhoea since childhood, and was diagnosed with CF. B. pseudomallei was cultured from his sputum during three different admissions between 2013 and 2016. However, the patient succumbed to end stage of respiratory failure in 2017 despite antibiotics treatment against B.pseudomallei. The isolates were compared using multilocus-sequence typing and repetitive-element polymerase chain reaction (PCR), and confirmed that two of the isolates were of same sequence type, which may indicate relapse.

    CONCLUSIONS: CF patients should be aware of melioidosis in endemic regions, as it is an emerging infectious disease, especially when persistent or recurrent respiratory symptoms and signs of infection occur. The high prevalence rates of melioidosis in Malaysia warrants better management options to improve quality of life, and life expectancy in patients with CF. Travel activities to endemic regions should also be given more consideration, as this would be crucial to identify and initiate appropriate empiric treatment.

    Matched MeSH terms: Burkholderia pseudomallei/drug effects; Burkholderia pseudomallei/genetics; Burkholderia pseudomallei/isolation & purification
  6. Fulltext Functional characterizations of effector protein BipC, a type III secretion system protein, in Burkholderia pseudomallei pathogenesis
    Kang WT, Vellasamy KM, Chua EG, Vadivelu J
    J Infect Dis, 2015 Mar 1;211(5):827-34.
    PMID: 25165162 DOI: 10.1093/infdis/jiu492
    OBJECTIVES: The bsa locus of Burkholderia pseudomallei encodes several proteins that are components of the type III secretion system (TTSS). BipC was postulated as one of the TTSS-3 effector proteins, but its role in the pathogenesis of B. pseudomallei infection is not well understood. Thus, the aim of this study was to determine its role(s) in the virulence of B. pseudomallei pathogenesis.
    METHODS: A bipC TTSS-3-deficient strain of B. pseudomallei and complemented strains were generated to assess the role of BipC as a type III translocation apparatus. Human cell lines and a mouse model of melioidosis were used for in vitro and in vivo assays, respectively.
    RESULTS: A significant 2-fold reduction was demonstrated in the percentage of adherence, invasion, intracellular survival, and phagosomal escape of the bipC mutant. Interestingly, microscopic studies have shown that BipC was capable of delayed B. pseudomallei actin-based motility. The virulence of the mutant strain in a murine model of melioidosis demonstrated that the bipC mutant was less virulent, compared with the wild type.
    CONCLUSION: The results suggested that BipC possesses virulence determinants that play significant roles in host cell invasion and immune evasion.
    KEYWORDS: BipC; Burkholderia pseudomallei; host cell invasion; type III secretion system; type III translocation apparatus; virulence
    Matched MeSH terms: Burkholderia pseudomallei/genetics; Burkholderia pseudomallei/metabolism; Burkholderia pseudomallei/pathogenicity*
  7. Fulltext An unusual case of primary melioidotic prostatic abscess complicated by perianal abscess
    Chee YC, Chee YN
    IDCases, 2018;11:51-52.
    PMID: 29349040 DOI: 10.1016/j.idcr.2018.01.001
    Burkholderia pseudomallei is recognized to cause severe and fatal infections. Most of the infections caused by this facultative intracellular gram-negative bacterium are pneumonia, soft tissue, genito-urinary and central nervous system infection. We report an unusual case of primary prostatic abscess complicated by perianal abscess caused by Burkholderia pseudomallei. Melioidosis related anorectal infections have not been previously reported in the literature.
    Matched MeSH terms: Burkholderia pseudomallei
  8. Fulltext Melioidosis presenting as epididymo-orchitis
    Koh KB
    Singapore Med J, 1995 Aug;36(4):446.
    PMID: 8919168
    We report a rare case of suppurative epididymo-orchitis caused by Pseudomonas pseudomallei in a 56-year-old male. This is a gram negative bacillus found mainly in tropical zones. Diagnosis was reached by culture of the organisms after drainage of the scrotal abscess, and the patient was treated by a course of oral chloramphenicol 500 mg qid for 6 months.
    Matched MeSH terms: Burkholderia pseudomallei
  9. Fulltext Burkholderia pseudomallei suppresses Caenorhabditis elegans immunity by specific degradation of a GATA transcription factor
    Lee SH, Wong RR, Chin CY, Lim TY, Eng SA, Kong C, et al.
    Proc Natl Acad Sci U S A, 2013 Sep 10;110(37):15067-72.
    PMID: 23980181 DOI: 10.1073/pnas.1311725110
    Burkholderia pseudomallei is a Gram-negative soil bacterium that infects both humans and animals. Although cell culture studies have revealed significant insights into factors contributing to virulence and host defense, the interactions between this pathogen and its intact host remain to be elucidated. To gain insights into the host defense responses to B. pseudomallei infection within an intact host, we analyzed the genome-wide transcriptome of infected Caenorhabditis elegans and identified ∼6% of the nematode genes that were significantly altered over a 12-h course of infection. An unexpected feature of the transcriptional response to B. pseudomallei was a progressive increase in the proportion of down-regulated genes, of which ELT-2 transcriptional targets were significantly enriched. ELT-2 is an intestinal GATA transcription factor with a conserved role in immune responses. We demonstrate that B. pseudomallei down-regulation of ELT-2 targets is associated with degradation of ELT-2 protein by the host ubiquitin-proteasome system. Degradation of ELT-2 requires the B. pseudomallei type III secretion system. Together, our studies using an intact host provide evidence for pathogen-mediated host immune suppression through the destruction of a host transcription factor.
    Matched MeSH terms: Burkholderia pseudomallei/genetics; Burkholderia pseudomallei/immunology; Burkholderia pseudomallei/pathogenicity*
  10. Fulltext Detection of Burkholderia pseudomallei toxin-mediated inhibition of protein synthesis using a Caenorhabditis elegans ugt-29 biosensor
    Wong RR, Kong C, Lee SH, Nathan S
    Sci Rep, 2016 06 07;6:27475.
    PMID: 27273550 DOI: 10.1038/srep27475
    Toxins are believed to play a crucial role in Burkholderia pseudomallei pathogenicity, however to date, only a few have been identified. The discovery of additional toxic molecules is limited by the lack of a sensitive indicator of B. pseudomallei toxicity. Previously, from a whole genome transcriptome analysis of B. pseudomallei-infected Caenorhabditis elegans, we noted significant overexpression of a number of worm genes encoding detoxification enzymes, indicating the host's attempt to clear bacterial toxic molecules. One of these genes, ugt-29, a family member of UDP-glucuronosyltransferases, was the most robustly induced phase II detoxification gene. In this study, we show that strong induction of ugt-29 is restricted to infections by the most virulent species among the pathogens tested. We also noted that ugt-29 is activated upon disruption of host protein synthesis. Hence, we propose that UGT-29 could be a promising biosensor to detect B. pseudomallei toxins that compromise host protein synthesis. The identification of bactobolin, a polyketide-peptide hybrid molecule, as a toxic molecule of B. pseudomallei further verifies the utilization of this surveillance system to search for bacterial toxins. Hence, a ugt-29 based reporter should be useful in screening for other molecules that inhibit host protein synthesis.
    Matched MeSH terms: Burkholderia pseudomallei/pathogenicity*
  11. Fulltext Fatal co-infection--melioidosis and leptospirosis
    Hin HS, Ramalingam R, Chunn KY, Ahmad N, Ab Rahman J, Mohamed MS
    Am J Trop Med Hyg, 2012 Oct;87(4):737-40.
    PMID: 22826499 DOI: 10.4269/ajtmh.2012.12-0165
    Co-infection of melioidosis and leptospirosis is uncommon. We report here four such cases, confirmed by blood culture for melioidosis and blood polymerase-chain reaction for leptospirosis, which occurred among rescuers involved in a search and rescue operation for a young man who was suspected to have drowned in Lubuk Yu, a recreational forest in Pahang, Malaysia. Despite treatment, three of the patients died from the co-infection.
    Matched MeSH terms: Burkholderia pseudomallei/isolation & purification*
  12. Fulltext Outbreak of melioidosis and leptospirosis co-infection following a rescue operation
    Mohamed MS, Khair MT, How SH, Rajalingam R, Sahhir K, Norazah A, et al.
    Med J Malaysia, 2012 Jun;67(3):293-7.
    PMID: 23082420 MyJurnal
    We analyzed the epidemiological data of all people who were involved in the search and rescue operation in Lubuk Yu, a natural recreational forest with waterfall and stream. The hospital admission records of the cases who fulfilled the case definition and the environmental samples result taken at Lubuk Yu recreational area were studied. 153 people were exposed to this outbreak, 85 (55.5%) were professional rescuers from various government agencies and 68 (44.5%) were villagers. 21 fulfilled the case definition. Ten cases were confirmed melioidosis, six melioidosis alone and four coinfected with leptospirosis. There were eight deaths in this outbreak, seven were villagers and one professional rescuer. Overall case fatality was 70%. All confirmed melioidosis cases and seven who died had diabetes mellitus. The morbidity rate were higher among the villagers, 23.5% compared to professional rescuers, 5.9%. The case fatality rate were also higher in this group which was 100% compared to 33.3% in professional rescuers. The soil and water samples in Lubuk Yu recreational area were positive for leptospira and Burkholderia pseudomallei. The presence of co-infection and co-morbidities especially diabetes mellitus among the exposed led to the high mortality in this outbreak hence a high index of suspicion is important among the healthcare professionals in the management of melioidosis cases. To avoid similar incident in future, search and rescue operation should be only conducted by professional rescuers with appropriate personal protective equipment. A register of rescuers should be maintained for surveillance and follow up if necessary.
    Matched MeSH terms: Burkholderia pseudomallei/isolation & purification
  13. Development of a multiplex PCR assay for rapid identification of Burkholderia pseudomallei, Burkholderia thailandensis, Burkholderia mallei and Burkholderia cepacia complex
    Koh SF, Tay ST, Sermswan R, Wongratanacheewin S, Chua KH, Puthucheary SD
    J Microbiol Methods, 2012 Sep;90(3):305-8.
    PMID: 22705921 DOI: 10.1016/j.mimet.2012.06.002
    We have developed a multiplex PCR assay for rapid identification and differentiation of cultures for Burkholderia pseudomallei, Burkholderia thailandensis, Burkholderia mallei and Burkholderia cepacia complex. The assay is valuable for use in clinical and veterinary laboratories, and in a deployable laboratory during outbreaks.
    Matched MeSH terms: Burkholderia pseudomallei/genetics*
  14. Burkholderia thailandensis whole cell antigen cross-reacts with B. pseudomallei antibodies from patients with melioidosis in an immunofluorescent assay
    Puthucheary SD, Anuar AS, Tee TS
    Southeast Asian J. Trop. Med. Public Health, 2010 Mar;41(2):395-400.
    PMID: 20578523
    An immunofluorescent assay (IFAT) using whole cell antigen derived from Burkholderia thailandensis used for detection of total antibodies to Burkholderia pseudomallei, was found to compare favorably with a previous published report on a B. pseudomallei IFAT assay. At a 1:20 cut-off titer, the assay had high sensitivity (98.9%) and satisfactory specificity (92.3%), when tested against sera from 94 patients suspected of melioidosis. Sera from 12 patients with culture proven melioidosis gave absolute concordance with the 2 test antigens. No sera from 50 blood donors had a titer of > or =20. Cross-reactivity with patients' sera positive for Chlamydia, Mycoplasma, Legionella and typhoid was not observed, except for 3 sera from typhus patients and one from a patient with leptospirosis. The major advantage of this assay is that the cultivation and preparation of B. thailandensis as antigen can be carried out in any laboratory with basic microbiological set-up. The serodiagnosis of melioidosis can be made safe for medical laboratory personnel, particularly in B. pseudomallei endemic regions.
    Matched MeSH terms: Burkholderia pseudomallei/immunology
  15. Genome-wide prediction and annotation of Burkholderia pseudomallei AraC/XylS family transcription regulator
    Lim BS, Chong CE, Zamrod Z, Nathan S, Mohamed R
    In Silico Biol. (Gedrukt), 2007;7(4-5):389-97.
    PMID: 18391231
    Many members of the AraC/XylS family transcription regulator have been proven to play a critical role in regulating bacterial virulence factors in response to environmental stress. By using the Hidden Markov Model (HMM) profile built from the alignment of a 99 amino acid conserved domain sequence of 273 AraC/XylS family transcription regulators, we detected a total of 45 AraC/XylS family transcription regulators in the genome of the Gram-negative pathogen, Burkholderia pseudomallei. Further in silico analysis of each detected AraC/XylS family transcription regulatory protein and its neighboring genes allowed us to make a first-order guess on the role of some of these transcription regulators in regulating important virulence factors such as those involved in three type III secretion systems and biosynthesis of pyochelin, exopolysaccharide (EPS) and phospholipase C. This paper has demonstrated an efficient and systematic genome-wide scale prediction of the AraC/XylS family that can be applied to other protein families.
    Matched MeSH terms: Burkholderia pseudomallei/genetics*
  16. Fulltext Evaluation of recombinant antigens for diagnosis of melioidosis
    Allwood EM, Logue CA, Hafner GJ, Ketheesan N, Norton RE, Peak IR, et al.
    FEMS Immunol. Med. Microbiol., 2008 Oct;54(1):144-53.
    PMID: 18657105 DOI: 10.1111/j.1574-695X.2008.00464.x
    Burkholderia pseudomallei, the causative agent of melioidosis, is endemic to Southeast Asia and northern Australia. Clinical manifestations of the disease are diverse, ranging from chronic localized infection to acute septicaemia, with death occurring within 24-48 h after the onset of symptoms. Definitive diagnosis of melioidosis involves bacterial culture and identification, with results obtained within 3-4 days. This delayed diagnosis is a major contributing factor to high mortality rates. Rapid diagnosis is vital for successful management of the disease. This study describes the purification and evaluation of three recombinant antigenic proteins, BPSL0972, BipD and OmpA from B. pseudomallei 08, for their potential in the serodiagnosis of melioidosis using an indirect enzyme-linked immunosorbent assay (ELISA) method. The recombinant proteins were evaluated using 74 serum samples from culture-confirmed melioidosis patients from Malaysia, Thailand and Australia. In addition, 62 nonmelioidosis controls consisting of serum samples from clinically suspected melioidosis patients (n=20) and from healthy blood donors from an endemic region (n=18) and a nonendemic region (n=24) were included. The indirect ELISAs using BipD and BPSL0972 as antigens demonstrated poor to moderate sensitivities (42% and 51%, respectively) but good specificity (both 100%). In contrast, the indirect ELISA using OmpA as an antigen achieved 95% sensitivity and 98% specificity. These results highlight the potential for OmpA to be used in the serodiagnosis of melioidosis in an endemic area.
    Matched MeSH terms: Burkholderia pseudomallei/immunology*
  17. Pacemaker infection secondary to burkholderia pseudomallei
    Zainal Abidin I, Syed Tamin S, Huat Tan L, Chong WP, Azman W
    Pacing Clin Electrophysiol, 2007 Nov;30(11):1420-2.
    PMID: 17976112
    Infection is a relatively rare but devastating complication of intracardiac device implantation. Burkholderia pseudomallei is the organism which causes melioidosis, an endemic and lethal infection in the tropics. We describe a case of pacemaker infection secondary to Burkholderia pseudomallei, which was treated by explantation of the device and appropriate antimicrobial therapy.
    Matched MeSH terms: Burkholderia pseudomallei*
  18. Fulltext Computational discovery and RT-PCR validation of novel Burkholderia conserved and Burkholderia pseudomallei unique sRNAs
    Khoo JS, Chai SF, Mohamed R, Nathan S, Firdaus-Raih M
    BMC Genomics, 2012;13 Suppl 7:S13.
    PMID: 23282220 DOI: 10.1186/1471-2164-13-S7-S13
    The sRNAs of bacterial pathogens are known to be involved in various cellular roles including environmental adaptation as well as regulation of virulence and pathogenicity. It is expected that sRNAs may also have similar functions for Burkholderia pseudomallei, a soil bacterium that can adapt to diverse environmental conditions, which causes the disease melioidosis and is also able to infect a wide variety of hosts.
    Matched MeSH terms: Burkholderia pseudomallei/genetics*
  19. Melioidosis imported into Nepal
    Shrestha N, Sharma S, Khanal B, Bhatta N, Dhakal S
    Scand. J. Infect. Dis., 2005;37(1):64-6.
    PMID: 15764193
    This is a report of the first recognized case of melioidosis in Nepal. Illness began 1 month after returning from Malaysia after a 1 y stay. The case highlights the importance of ascertaining the travel history in any patient with a suspected infectious disease in this age of global travel.
    Matched MeSH terms: Burkholderia pseudomallei/isolation & purification
  20. Bacterial expression of the scFv fragment of a recombinant antibody specific for Burkholderia pseudomallei exotoxin
    Su YC, Lim KP, Nathan S
    J. Biochem. Mol. Biol., 2003 Sep 30;36(5):493-8.
    PMID: 14536033
    The scFv antibody towards the Burkholderia pseudomallei exotoxin was previously constructed by phage display and exhibited good specificity towards the exotoxin. We report here the optimization of the scFv expression in an E. coli expression system. Four different E. coli strains (ER2537, TG1, HB2151, and XL1-Blue) were examined for optimal expression of the scFv protein. Two types of carbon source (i.e. 0.2% glucose and 0.2% glycerol) were also tested for their ability to induce the scFv expression. Cells that carried the scFv construct were grown at 30 degrees C and induced with 0.05 mM IPTG. The expression was then monitored by SDS-PAGE, Western blotting, and indirect ELISA. The Western blot profile showed different levels of the scFv expression among the host strains; XL1-Blue exhibited the highest level of the scFv protein expression. Glycerol at a concentration of 0.2% (v/v) significantly increased the scFv protein expression level when compared to 0.2% (w/v) glucose. Further optimization demonstrated that the scFv protein expression in XL1-Blue was the most optimal with a glycerol concentration as low as 0.05%. However, by indirect ELISA, only the scFv protein that was expressed in 0.2% (v/v) glycerol exhibited high specificity towards the Burkholderia pseudomallei exotoxin.
    Matched MeSH terms: Burkholderia pseudomallei/immunology*
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