Displaying publications 21 - 40 of 463 in total

Abstract:
Sort:
  1. Fulltext Draft Genome Sequence of Blood Disease Bacterium A2 HR-MARDI, a Pathogen Causing Banana Bacterial Wilt
    Badrun R, Abu Bakar N, Laboh R, Redzuan R, Bala Jaganath I
    Genome Announc, 2017 Jun 01;5(22).
    PMID: 28572313 DOI: 10.1128/genomeA.00408-17
    Blood disease bacterium A2 HR-MARDI was isolated from banana plants infected with banana blood disease and which were planted in Kuala Kangsar, Malaysia. Here, we report a draft genome sequence of blood disease bacterium A2 HR-MARDI, which could provide important information on the virulence mechanism of this pathogen.
    Matched MeSH terms: Virulence
  2. Molecular characterisation and potential pathogenicity analysis of Acanthamoeba isolated from recreational lakes in Peninsular Malaysia
    Abdul Halim R, Mohd Hussain RH, Aazmi S, Halim H, Ahmed Khan N, Siddiqui R, et al.
    J Water Health, 2023 Sep;21(9):1342-1356.
    PMID: 37756200 DOI: 10.2166/wh.2023.186
    The present study aims to identify the Acanthamoeba genotypes and their pathogenic potential in three recreational lakes in Malaysia. Thirty water samples were collected by purposive sampling between June and July 2022. Physical parameters of water quality were measured in situ while chemical and microbiological analyses were performed in the laboratory. The samples were vacuum filtered through nitrate filter, cultured onto non-nutrient agar and observed microscopically for amoebic growth. DNAs from positive samples were extracted and made to react with polymerase chain reaction using specific primers. Physiological tolerance tests were performed for all Acanthamoeba-positive samples. The presence of Acanthamoeba was found in 26 of 30 water samples by PCR. The highest rate in lake waters contaminated with amoeba was in Biru Lake (100%), followed by Titiwangsa Lake (80%) and Shah Alam Lake (80%). ORP, water temperature, pH and DO were found to be significantly correlated with the presence of Acanthamoeba. The most common genotype was T4. Temperature- and osmo-tolerance tests showed that 8 (30.8%) of the genotypes T4, T9 and T11 were highly pathogenic. The presence of genotype T4 in habitats related to human activities supports the relevance of this amoeba as a potential public health concern.
    Matched MeSH terms: Virulence
  3. Fulltext Aquatic Peptide: The Potential Anti-Cancer and Anti-Microbial Activity of GE18 Derived from Pathogenic Fungus Aphanomyces invadans
    Velayutham M, Priya PS, Sarkar P, Murugan R, Almutairi BO, Arokiyaraj S, et al.
    Molecules, 2023 Sep 21;28(18).
    PMID: 37764521 DOI: 10.3390/molecules28186746
    Small molecules as well as peptide-based therapeutic approaches have attracted global interest due to their lower or no toxicity in nature, and their potential in addressing several health complications including immune diseases, cardiovascular diseases, metabolic disorders, osteoporosis and cancer. This study proposed a peptide, GE18 of subtilisin-like peptidase from the virulence factor of aquatic pathogenic fungus Aphanomyces invadans, which elicits anti-cancer and anti-microbial activities. To understand the potential GE18 peptide-induced biological effects, an in silico analysis, in vitro (L6 cells) and in vivo toxicity assays (using zebrafish embryo), in vitro anti-cancer assays and anti-microbial assays were performed. The outcomes of the in silico analyses demonstrated that the GE18 peptide has potent anti-cancer and anti-microbial activities. GE18 is non-toxic to in vitro non-cancerous cells and in vivo zebrafish larvae. However, the peptide showed significant anti-cancer properties against MCF-7 cells with an IC50 value of 35.34 µM, at 24 h. Besides the anti-proliferative effect on cancer cells, the peptide exposure does promote the ROS concentration, mitochondrial membrane potential and the subsequent upregulation of anti-cancer genes. On the other hand, GE18 elicits significant anti-microbial activity against P. aeruginosa, wherein GE18 significantly inhibits bacterial biofilm formation. Since the peptide has positively charged amino acid residues, it targets the cell membrane, as is evident in the FESEM analysis. Based on these outcomes, it is possible that the GE18 peptide is a significant anti-cancer and anti-microbial molecule.
    Matched MeSH terms: Virulence Factors
  4. Fulltext Genomic characterization, transcriptome analysis, and pathogenicity of the Nipah virus (Indian isolate)
    Mohandas S, Shete A, Sarkale P, Kumar A, Mote C, Yadav P
    Virulence, 2023 Dec;14(1):2224642.
    PMID: 37312405 DOI: 10.1080/21505594.2023.2224642
    Nipah virus (NiV) is a high-risk pathogen which can cause fatal infections in humans. The Indian isolate from the 2018 outbreak in the Kerala state of India showed ~ 4% nucleotide and amino acid difference in comparison to the Bangladesh strains of NiV and the substitutions observed were mostly not present in the region of any functional significance except for the phosphoprotein gene. The differential expression of viral genes was observed following infection in Vero (ATCC® CCL-81™) and BHK-21 cells. Intraperitoneal infection in the 10-12-week-old, Syrian hamster model induced dose dependant multisystemic disease characterized by prominent vascular lesions in lungs, brain, kidney and extra vascular lesions in brain and lungs. Congestion, haemorrhages, inflammatory cell infiltration, thrombosis and rarely endothelial syncitial cell formation were seen in the blood vessels. Intranasal infection resulted in respiratory tract infection characterised by pneumonia. The model showed disease characteristics resembling the human NiV infection except that of myocarditis similar to that reported by NiV-Malaysia and NiV-Bangladesh isolates in hamster model. The variation observed in the genome of the Indian isolate at the amino acid levels should be explored further for any functional significance.
    Matched MeSH terms: Virulence
  5. Fulltext Fungal genotyping - current clinical application
    Harun A
    Malays J Med Sci, 2014 Nov-Dec;21(6):1-2.
    PMID: 25897275
    The emergence of fungal species as opportunistic pathogens has warranted further studies on their pathogenicity, epidemiology, and transmissibility. Fungal genotyping has been employed to study the genetic relatedness within the organism, in order to obtain answers to epidemiological questions (such as in outbreak confirmation) as well as to provide basis for the improvement for patients care. Various fungal genotyping methods have been previously published, which can be chosen depending on the intended use and the capability of individual laboratory.
    Matched MeSH terms: Virulence
  6. Prevalence of Helicobacter pylori cagA, babA2, and dupA genotypes and correlation with clinical outcome in Malaysian patients with dyspepsia
    Osman HA, Hasan H, Suppian R, Hassan S, Andee DZ, Abdul Majid N, et al.
    Turk J Med Sci, 2015;45(4):940-6.
    PMID: 26422871
    BACKGROUND/AIM: The severity of disease outcome in dyspepsia has been attributed to Helicobacter pylori virulence genes. The aim of this study was to determine the distribution of H. pylori virulence genes (cagA, babA2, and dupA) and to determine whether or not there arises a significant correlation with clinical dyspepsia outcomes.

    MATERIALS AND METHODS: H. pylori genotypes cagA, babA2, and dupA were identified by polymerase chain reactions from gastric biopsy samples in 105 H. pylori-positive patients.

    RESULTS: The positive rates for cagA, babA2, and dupA genes in H. pylori dyspeptic patients were 69.5%, 41.0%, and 22.9%, respectivel cagA was more prevalent in Indians (39.7%), babA2 was more prevalent in Malays (39.5%), and dupA detection occurred more frequently in both Indians and Malays and at the same rate (37.5%). The Chinese inhabitants had the lowest prevalence of the three genes. Nonulcer disease patients had a significantly higher distribution of cagA (76.7%), babA2 (74.4%), and dupA (75.0%). There was no apparent association between these virulence genes and the clinical outcomes.

    CONCLUSION: The lower prevalence of these genes and variations among different ethnicities implies that the strains are geographically and ethnically dependent. None of the virulence genes were knowingly beneficial in predicting the clinical outcome of H. pylori infection in our subjects.

    Matched MeSH terms: Virulence/genetics; Virulence Factors/genetics*
  7. Fulltext Gut bacteria influence Blastocystis sp. phenotypes and may trigger pathogenicity
    Rajamanikam A, Isa MNM, Samudi C, Devaraj S, Govind SK
    PLoS Negl Trop Dis, 2023 Mar;17(3):e0011170.
    PMID: 36989208 DOI: 10.1371/journal.pntd.0011170
    Whilst the influence of intestinal microbiota has been shown in many diseases such as irritable bowel syndrome, colorectal cancer, and aging, investigations are still scarce on its role in altering the nature of other infective organisms. Here we studied the association and interaction of Blastocystis sp. and human intestinal microbiota. In this study, we investigated the gut microbiome of Blastocystis sp.-free and Blastocystis sp. ST3-infected individuals who are symptomatic and asymptomatic. We tested if the expression of phenotype and pathogenic characteristics of Blastocystis sp. ST3 was influenced by the alteration of its accompanying microbiota. Blastocystis sp. ST3 infection alters bacterial composition. Its presence in asymptomatic individuals showed a significant effect on microbial richness compared to symptomatic ones. Inferred metagenomic findings suggest that colonization of Blastocystis sp. ST3 could contribute to the alteration of microbial functions. For the first time, we demonstrate the influence of bacteria on Blastocystis sp. pathogenicity. When Blastocystis sp. isolated from a symptomatic individual was co-cultured with bacterial suspension of Blastocystis sp. from an asymptomatic individual, the parasite demonstrated increased growth and reduced potential pathogenic expressions. This study also reveals that Blastocystis sp. infection could influence microbial functions without much effect on the microbiota diversity itself. Our results also demonstrate evidence on the influential role of gut microbiota in altering the characteristics of the parasite, which becomes the basis for the contradictory findings on the parasite's pathogenic role seen across different studies. Our study provides evidence that asymptomatic Blastocystis sp. in a human gut can be triggered to show pathogenic characteristics when influenced by the intestinal microbiota.
    Matched MeSH terms: Virulence
  8. Fulltext Autoantibodies and autoimmune disorders in SARS-CoV-2 infection: pathogenicity and immune regulation
    Darmarajan T, Paudel KR, Candasamy M, Chellian J, Madheswaran T, Sakthivel LP, et al.
    Environ Sci Pollut Res Int, 2022 Aug;29(36):54072-54087.
    PMID: 35657545 DOI: 10.1007/s11356-022-20984-7
    Coronavirus disease 2019 (COVID-19) is an infectious disease associated with the respiratory system caused by the SARS-CoV-2 virus. The aim of this review article is to establish an understanding about the relationship between autoimmune conditions and COVID-19 infections. Although majority of the population have been protected with vaccines against this virus, there is yet a successful curative medication for this disease. The use of autoimmune medications has been widely considered to control the infection, thus postulating possible relationships between COVID-19 and autoimmune diseases. Several studies have suggested the correlation between autoantibodies detected in patients and the severity of the COVID-19 disease. Studies have indicated that the SARS-CoV-2 virus can disrupt the self-tolerance mechanism of the immune system, thus triggering autoimmune conditions. This review discusses the current scenario and future prospects of promising therapeutic strategies that may be employed to regulate such autoimmune conditions.
    Matched MeSH terms: Virulence
  9. Expressions of selected microRNAs in gastric cancer patients and their association with Helicobacter pylori and its cag pathogenicity island
    Rai RP, Syed A, Elgorban AM, Abid I, Wong LS, Khan MS, et al.
    Microb Pathog, 2025 May;202:107442.
    PMID: 40049249 DOI: 10.1016/j.micpath.2025.107442
    BACKGROUND: Helicobacter pylori infection and the resulting inflammation of the stomach are widely recognized as the primary risk factors for the development of gastric cancer (human health). Despite numerous attempts, the correlation between various virulence factors of H. pylori and stomach cancer remains mainly unexplained. The cag pathogenicity island (cagPAI) is a widely recognized indicator of virulence in H. pylori. MicroRNAs play crucial roles in a wide range of biological and pathological processes and dysregulated expressions of miRNAs have been detected in numerous cancer types. However, research on the correlation between H. pylori infection and its cagPAI, as well as the differential expression of microRNAs in gastric cancer, is lacking.

    AIM: The aim of this study was to examine the differential expression of miRNAs in 80 patients with gastric cancer, specifically in connection to the presence of H. pylori and its cag pathogenicity island (cagPAI).

    METHODS: Biopsies of 80 gastric cancer patients were collected and used for H. pylori DNA isolation and tissue miRNA isolation, and further analyzed for cagPAI and miRNA expression and their association.

    RESULTS: Elevated levels of miR-21, miR-155, and miR-223 were detected in malignant tissues. The expression of miR-21 and miR-223 was considerably elevated in biopsies that tested positive for H. pylori, whereas the expression of miR-34a was reduced. H. pylori cagPAI samples that are functionally intact exhibit greater expression of miR-21 and miR-223 compared to cagPAI samples that are partially deleted, in both normal and malignant tissues.

    CONCLUSION: Thus, the novelty of our study lies in its focus on the differential expression of specific miRNAs in relation to the functional integrity of the cagPAI in H. pylori-infected gastric cancer patients, offering a more detailed understanding of the interplay between H. pylori virulence factors and miRNA regulation than previous studies.

    Matched MeSH terms: Virulence/genetics; Virulence Factors/genetics
  10. Nasal methicillin-resistant Staphylococcus aureus in adult atopic dermatitis: Severity and virulence associations-A cross-sectional study
    Jomah AA, Alshammari Y, Al-Fadhli AH, Al-Dhafiri SA, Al Benwan K, Allafi A, et al.
    J Int Med Res, 2026 Oct;54(10):3000605261497554.
    PMID: 42960523 DOI: 10.1177/03000605261497554
    ObjectivesTo investigate the prevalence of nasal methicillin-resistant Staphylococcus aureus (MRSA) colonization among adults with atopic dermatitis and explore its association with disease severity.MethodsThis cross-sectional study included 100 adults (≥18 years) with dermatologist-confirmed atopic dermatitis who attended dermatology outpatient clinics in Kuwait. Patients with nonatopic eczema, major systemic illnesses, or skin malignancy were excluded. Disease severity was assessed using the validated Investigator's Global Assessment for Atopic Dermatitis. Nasal swabs were collected, and S. aureus isolates were identified using culture, Gram staining, and catalase and coagulase tests, followed by confirmation using the VITEK® 2 system. Methicillin resistance (mecA) and selected staphylococcal virulence genes, including the classical (sea, seb, sec, sed, and see) and nonclassical staphylococcal enterotoxins (seg, seh, and sei), Panton-Valentine leukocidin (pvl), and toxic shock syndrome toxin-1 (tsst-1) were determined using polymerase chain reaction. Antimicrobial susceptibility profiles were assessed using the Clinical and Laboratory Standards Institute disk diffusion method.ResultsS. aureus colonization is a key feature of atopic dermatitis and is closely associated with disease activity. This study investigated the prevalence of nasal MRSA colonization among adults with atopic dermatitis and examined its association with disease severity and virulence gene carriage. Overall, 53% of patients were colonized with S. aureus, of whom 71.7% carried MRSA. MRSA colonization was significantly associated with older age and greater disease severity. Virulence gene analysis in MRSA isolates revealed higher frequency of seg and sei, whereas the presence of sea and tsst-1 were significantly associated with more severe atopic dermatitis.ConclusionsAdults with atopic dermatitis showed a high prevalence of nasal MRSA colonization. The predominance of enterotoxin gene cluster genes and the association of sea and tsst-1 with greater disease severity highlight the potential clinical importance of nasal MRSA as a reservoir of virulent strains in atopic dermatitis.
    Matched MeSH terms: Virulence/genetics; Virulence Factors/genetics
  11. Fulltext Microbiological and clinical characteristics of hypervirulent Klebsiella pneumoniae isolated from patients in tertiary centers: a retrospective study
    Khairuddin A, Nik Zuraina NMN, Mohamad Nasir NS, Chua WC, Abdul Halim HS, Yusof W, et al.
    PeerJ, 2025;13:e20198.
    PMID: 41116789 DOI: 10.7717/peerj.20198
    This cross-sectional, retrospective study aimed to investigate the prevalence of hypervirulent Klebsiella pneumoniae (hvKp), its virulence-associated genes, and the clinical manifestations of hvKp infections. HvKp was defined in this study as K. pneumoniae with a positive string test and harboring the serotype K1 or K2 gene. A total of 180 isolates from various clinical specimens were collected from four main hospitals in Kelantan. All isolates were examined for the hypermucoviscous phenotype using the string test, while the presence of capsular serotypes and other virulence genes (rmpA, rmpA2, iucA, magA, and peg-344) was determined by polymerase chain reaction (PCR). Patients' clinical data were collected and analyzed. String test-positive isolates (23.8%, n = 43) were identified as hypermucoviscous K. pneumoniae (hmKp). Capsular serotypes K1 and K2 were detected in 11.1% (n = 20) and 6.1% (n = 11) of isolates, respectively. The prevalence of hvKp was 9.4% (n = 17). All hvKp isolates were positive for rmpA, rmpA2, iucA, and peg-344 genes, while all ten hvKp-K1 serotype isolates were positive for magA, the K1 serotype-specific gene. The associations between all corresponding virulence genes and serotypes K1 and K2 were statistically significant (p
    Matched MeSH terms: Virulence/genetics; Virulence Factors/genetics
  12. Fulltext Draft genome sequencing data of a pathogenic Pantoea stewartii subspecies stewartii strain SQT1 causing bronzing disease of jackfruit in Malaysia
    Ibrahim R, Ismail-Suhaimy NW, Shu-Qing T, Ismail SI, Ina-Salwany MY, Yusof MT, et al.
    Data Brief, 2020 Jun;30:105634.
    PMID: 32395592 DOI: 10.1016/j.dib.2020.105634
    A Gram-negative bacterium, Pantoea stewartii subspecies stewartii (P. stewartii subsp. stewartii) has been recognized as the causative agent for jackfruit bronzing disease in Malaysia. Here, we report the whole genome sequencing dataset of P. stewartii subsp. stewartii strain SQT1 isolated from local infected jackfruit. The paired-end libraries with an insert size of 350 bp was subjected to the Illumina Hiseq 4000, generating a genome size of 4,783,993 bp with a G+C content of 53.7%. A total protein of 4,671 was identified including virulence factors, resistance factors and secretion systems. Pantoea stewartii subsp. stewartii strain DC283 (NCBI accession no. CP017581.1) was used as a reference genome, where the query hit 72% coverage and average sequencing depth of 68. In total, 28,717 nucleotide polymorphisms, 520 small insertion/deletions and 142 structure variants were identified. The complete genome was deposited at the European Nucleotide Archive under the sample accession number ERP119356 and study accession number PRJEB36196.
    Matched MeSH terms: Virulence; Virulence Factors
  13. Characterization of Aquimarina hainanensis isolated from diseased mud crab Scylla serrata larvae in a hatchery
    Midorikawa Y, Shimizu T, Sanda T, Hamasaki K, Dan S, Lal MTBM, et al.
    J Fish Dis, 2020 May;43(5):541-549.
    PMID: 32147853 DOI: 10.1111/jfd.13151
    Mass mortality due to necrosis signs occurred in hatchery-reared zoea stage larvae of the mud crab Scylla serrata in Okinawa, Japan, and a causative bacterium was isolated. In this study, we identified and characterized the bacterium by genome analysis, biochemical properties and pathogenicity. The bacterium was a Gram-negative, non-motile, long rod, forming yellow colonies on a marine agar plate. It grew at 20-33°C (not at 37°C) and degraded chitin and gelatin. Phylogenetic analysis of the 16S rRNA gene sequence identified the bacterium as Aquimarina hainanensis. Genome sequence data obtained from Illumina MiSeq generated 29 contigs with 3.56 Mbp in total length and a G + C content of 32.5%. The predicted 16 chitinase genes, as putative virulence factors, had certain homologies with those of genus Aquimarina. Experimental infection with the bacterium conducted on larvae of four crustacean species, brine shrimp Artemia franciscana, freshwater shrimp Caridina multidentata, swimming crab Portunus trituberculatus and mud crab S. serrata, revealed that this bacterium was highly virulent to these species. The present study suggests that the bacterium caused mass mortality in mud crab seed production was A. hainanensis and can be widely pathogenic to crustaceans.
    Matched MeSH terms: Virulence; Virulence Factors
  14. Phylogenetic comparison between Type IX Secretion System (T9SS) protein components suggests evidence of horizontal gene transfer
    Emrizal R, Nor Muhammad NA
    PeerJ, 2020;8:e9019.
    PMID: 32617187 DOI: 10.7717/peerj.9019
    Porphyromonas gingivalis is one of the major bacteria that causes periodontitis. Chronic periodontitis is a severe form of periodontal disease that ultimately leads to tooth loss. Virulence factors that contribute to periodontitis are secreted by Type IX Secretion System (T9SS). There are aspects of T9SS protein components that have yet to be characterised. Thus, the aim of this study is to investigate the phylogenetic relationship between members of 20 T9SS component protein families. The Bayesian Inference (BI) trees for 19 T9SS protein components exhibit monophyletic clades for all major classes under Bacteroidetes with strong support for the monophyletic clades or its subclades that is consistent with phylogeny exhibited by the constructed BI tree of 16S rRNA. The BI tree of PorR is different from the 19 BI trees of T9SS protein components as it does not exhibit monophyletic clades for all major classes under Bacteroidetes. There is strong support for the phylogeny exhibited by the BI tree of PorR which deviates from the phylogeny based on 16S rRNA. Hence, it is possible that the porR gene is subjected to horizontal transfer as it is known that virulence factor genes could be horizontally transferred. Seven genes (porR included) that are involved in the biosynthesis of A-LPS are found to be flanked by insertion sequences (IS5 family transposons). Therefore, the intervening DNA segment that contains the porR gene might be transposed and subjected to conjugative transfer. Thus, the seven genes can be co-transferred via horizontal gene transfer. The BI tree of UgdA does not exhibit monophyletic clades for all major classes under Bacteroidetes which is similar to the BI tree of PorR (both are a part of the seven genes). Both BI trees also exhibit similar topology as the four identified clusters with strong support and have similar relative positions to each other in both BI trees. This reinforces the possibility that porR and the other six genes might be horizontally transferred. Other than the BI tree of PorR, the 19 other BI trees of T9SS protein components also exhibit evidence of horizontal gene transfer. However, their genes might undergo horizontal gene transfer less frequently compared to porR because the intervening DNA segment that contains porR is easily exchanged between bacteria under Bacteroidetes due to the presence of insertion sequences (IS5 family transposons) that flank it. In conclusion, this study can provide a better understanding about the phylogeny of T9SS protein components.
    Matched MeSH terms: Virulence; Virulence Factors
  15. Fulltext Biofilm architecture of Candida rugosa and effect of amphotericin b, caspofungin, fluconazole and voriconazole on its structure
    Sri Raja Rajeswari Mahalingam, Priya Madhavan, Chong, Pei Pei
    Malaysian Journal of Medicine and Health Sciences, 2019;15(102):2-2.
    MyJurnal
    Introduction: One of the most common aetiology of opportunistic fungal infections in humans is Candida species. The virulence of Candida species is due to repertoire of factors, specifically, the ability to form biofilms. Medical devices such as intravenous catheters, prosthetic heart valves and surgical interventions provide pathogenic microorganisms with a surface to adhere to form biofilm. Fungi present as biofilms are often resistant to antifungal treatment because these biofilms offer a protective barrier that prohibits the drugs to get to the active site of the fungi. The objective of this study is to investigate the biofilm architecture of Candida rugosa (C.rugosa) at different developmental phases and to identify Sessile Minimum Inhibition Concentrations (SMICs) of amphotericin B, caspofungin, fluconazole, and voriconazole for the biofilm of C. rugosa. Methods: Confocal scanning laser microscopy (CSLM) and scanning electron microscopy (SEM) were used to visualize C. rugosa biofilms at different developmental phases. The antifungal susceptibility test was performed using serial doubling dilution. The growth kinetics of Candida biofilms was quantified using XTT reduction assay and crystal violet assay. Results: From the antifungal susceptibility test, the biofilms had SMIC of >16μg/mL for amphotericin B, 6µg/mL for caspofungin, >64μg/mL for fluconazole and >16μg/ mL for voriconazole. From the SEM micrographs, C. rugosa biofilm have a structure composed of an adherent yeast cells and blastopores with hyphal elements. There were significant alterations in the morphology after exposure to antifungal agents. The quantitative measurement of the matrix thickness of embedded yeast cells were obtained from CLSM micrographs. Conclusion: In conclusion, the ability of C. rugosa to form biofilms may attribute to one of the virulence factors that causes reduced susceptibility to antifungal agents.
    Matched MeSH terms: Virulence; Virulence Factors
  16. Fulltext The heterogeneic distribution of Helicobacter pylori cag pathogenicity island reflects different pathologies in multiracial Malaysian population
    Hanafiah A, Razak SA, Neoh HM, Zin NM, Lopes BS
    Braz J Infect Dis, 2020 11 04;24(6):545-551.
    PMID: 33157035 DOI: 10.1016/j.bjid.2020.10.005
    BACKGROUND: Helicobacter pylori harbouring cag-pathogenicity island (cagPAI) which encodes type IV secretion system (T4SS) and cagA virulence gene are involved in inflammation of the gastric mucosa. We examined all the 27 cagPAI genes in 88 H. pylori isolates from patients of different ethnicities and examined the association of the intactness of cagPAI region with histopathological scores of the gastric mucosa.

    RESULTS: 96.6% (n=85) of H. pylori isolates were cagPAI-positive with 22.4% (19/85) having an intact cagPAI, whereas 77.6% (66/85) had a partial/rearranged cagPAI. The frequency of cag2 and cag14 were found to be significantly higher in H. pylori isolated from Malays, whereas cag4 was predominantly found in Chinese isolates. The cag24 was significantly found in higher proportions in Malay and Indian isolates than in Chinese isolates. The intactness of cagPAI region showed an association with histopathological scores of the gastric mucosa. Significant association was observed between H. pylori harbouring partial cagPAI with higher density of bacteria and neutrophil activity, whereas strains lacking cagPAI were associated with higher inflammatory score.

    CONCLUSIONS: The genotypes of H. pylori strains with various cagPAI rearrangement associated with patients' ethnicities and histopathological scores might contribute to the pathogenesis of H. pylori infection in a multi-ethnic population.

    Matched MeSH terms: Virulence/genetics
  17. An overview of the evolution of enterovirus 71 and its clinical and public health significance
    McMinn PC
    FEMS Microbiol Rev, 2002 Mar;26(1):91-107.
    PMID: 12007645
    Since its discovery in 1969, enterovirus 71 (EV71) has been recognised as a frequent cause of epidemics of hand-foot-and-mouth disease (HFMD) associated with severe neurological sequelae in a small proportion of cases. There has been a significant increase in EV71 epidemic activity throughout the Asia-Pacific region since 1997. Recent HFMD epidemics in this region have been associated with a severe form of brainstem encephalitis associated with pulmonary oedema and high case-fatality rates. The emergence of large-scale epidemic activity in the Asia-Pacific region has been associated with the circulation of three genetic lineages that appear to be undergoing rapid evolutionary change. Two of these lineages (B3 and B4) have not been described previously and appear to have arisen from an endemic focus in equatorial Asia, which has served as a source of virus for HFMD epidemics in Malaysia, Singapore and Australia. The third lineage (C2) has previously been identified [Brown, B.A. et al. (1999) J. Virol. 73, 9969-9975] and was primarily responsible for the large HFMD epidemic in Taiwan during 1998. As EV71 appears not to be susceptible to newly developed antiviral agents and a vaccine is not currently available, control of EV71 epidemics through high-level surveillance and public health intervention needs to be maintained and extended throughout the Asia-Pacific region. Future research should focus on (1) understanding the molecular genetics of EV71 virulence, (2) identification of the receptor(s) for EV71, (3) development of antiviral agents to ameliorate the severity of neurological disease and (4) vaccine development to control epidemics. Following the successful experience of the poliomyelitis control programme, it may be possible to control EV71 epidemics if an effective live-attenuated vaccine is developed.
    Matched MeSH terms: Virulence/genetics
  18. Fulltext Leptospiral Infection, Pathogenesis and Its Diagnosis-A Review
    Samrot AV, Sean TC, Bhavya KS, Sahithya CS, Chan-Drasekaran S, Palanisamy R, et al.
    Pathogens, 2021 Feb 01;10(2).
    PMID: 33535649 DOI: 10.3390/pathogens10020145
    Leptospirosis is a perplexing conundrum for many. In the existing literature, the pathophysiological mechanisms pertaining to leptospirosis is still not understood in full. Considered as a neglected tropical zoonotic disease, leptospirosis is culminating as a serious problem worldwide, seemingly existing as co-infections with various other unrelated diseases, including dengue and malaria. Misdiagnosis is also common as non-specific symptoms are documented extensively in the literature. This can easily lead to death, as the severe form of leptospirosis (Weil's disease) manifests as a complex of systemic complications, especially renal failure. The virulence of Leptospira sp. is usually attributed to the outer membrane proteins, including LipL32. With an armament of virulence factors at their disposal, their ability to easily adhere, invade and replicate within cells calls for a swift refinement in research progress to establish their exact pathophysiological framework. As an effort to reconstitute the current knowledge on leptospirosis, the basis of leptospiral infection, including its risk factors, classification, morphology, transmission, pathogenesis, co-infections and clinical manifestations are highlighted in this review. The various diagnostic techniques are also outlined with emphasis on their respective pros and cons.
    Matched MeSH terms: Virulence; Virulence Factors
  19. Fulltext Bacterial Biopolymer: Its Role in Pathogenesis to Effective Biomaterials
    Ghosh S, Lahiri D, Nag M, Dey A, Sarkar T, Pathak SK, et al.
    Polymers (Basel), 2021 Apr 12;13(8).
    PMID: 33921239 DOI: 10.3390/polym13081242
    Bacteria are considered as the major cell factories, which can effectively convert nitrogen and carbon sources to a wide variety of extracellular and intracellular biopolymers like polyamides, polysaccharides, polyphosphates, polyesters, proteinaceous compounds, and extracellular DNA. Bacterial biopolymers find applications in pathogenicity, and their diverse materialistic and chemical properties make them suitable to be used in medicinal industries. When these biopolymer compounds are obtained from pathogenic bacteria, they serve as important virulence factors, but when they are produced by non-pathogenic bacteria, they act as food components or biomaterials. There have been interdisciplinary studies going on to focus on the molecular mechanism of synthesis of bacterial biopolymers and identification of new targets for antimicrobial drugs, utilizing synthetic biology for designing and production of innovative biomaterials. This review sheds light on the mechanism of synthesis of bacterial biopolymers and its necessary modifications to be used as cell based micro-factories for the production of tailor-made biomaterials for high-end applications and their role in pathogenesis.
    Matched MeSH terms: Virulence; Virulence Factors
  20. Fulltext Pediatric brain abscess with fatal outcome caused by hypervirulent Klebsiella pneumoniae, serotype K2-ST65
    En ETS, Ismail N, Nasir NSM, Ismadi YKM, Zuraina NMNN, Hassan SA
    J Infect Public Health, 2023 Jul;16(7):1089-1092.
    PMID: 37224619 DOI: 10.1016/j.jiph.2023.05.015
    Hypervirulent Klebsiella pneumoniae (hvKp) is an emerging pathotype in addition to classical Klebsiella pneumoniae, with its ability to cause life-threatening, community-acquired metastatic infections even in healthy individuals. We presented a case of cerebral abscess preceded by otitis media in a 10-year-old child caused by hvKp. The isolates from blood pus aspirate were later identified as K. pneumoniae capsular serotype K2 and closely related to sequence type (ST65), with multiple hypervirulent genes detected (rmpA, rmpA2, iucA and peg344). She succumbed to death despite surgical drainage and susceptible antibiotic therapy. Clinicians should be cognizant of the rising incidence of hvKp infections in pediatric populations.
    Matched MeSH terms: Virulence/genetics
Related Terms
Filters
Contact Us

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links