Displaying publications 1 - 20 of 84 in total

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  1. Zainal N, Ser HL, Yin WF, Tee KK, Lee LH, Chan KG
    Antonie Van Leeuwenhoek, 2016 Mar;109(3):467-74.
    PMID: 26786500 DOI: 10.1007/s10482-016-0653-1
    A novel Streptomyces strain, MUSC 119(T), was isolated from a soil collected from a mangrove forest. Cells of MUSC 119(T) stained Gram-positive and formed light brownish grey aerial mycelium and grayish yellowish brown substrate mycelium on ISP 2 medium. A polyphasic approach was used to determine the taxonomic status of strain MUSC 119(T), which shows a range of phylogenetic and chemotaxonomic properties consistent with those of the genus Streptomyces. The cell wall peptidoglycan consisted of LL-diaminopimelic acid. The predominant menaquinones were identified as MK-9(H8), MK-9(H6) and MK-9(H4). The polar lipid profile consisted of phosphatidylinositol, phosphatidylethanolamine, glycolipids, diphosphatidylglycerol and four phospholipids. The predominant cellular fatty acids were anteiso-C15:0, iso-C16:0, and anteiso-C17:0. The cell wall sugars were glucose, mannose, ribose and rhamnose. The phylogenetic analysis based on 16S rRNA gene sequence similarity showed that strain MUSC119(T) to be closely related to Streptomyces rhizophilus JR-41(T) (99.0 % sequence similarity), S. panaciradicis 1MR-8(T) (98.9 %), S. gramineus JR-43(T) (98.8 %) and S. graminisoli JR-19(T) (98.7 %). These results suggest that MUSC 119(T) should be placed within the genus Streptomyces. DNA-DNA relatedness values between MUSC 119(T) to closely related strains ranged from 14.5 ± 1.3 to 27.5 ± 0.7 %. The G+C content was determined to be 72.6 mol  %. The polyphasic study of MUSC 119(T) showed that this strain represents a novel species, for which the name Streptomyces humi sp. nov. is proposed. The type strain of S. humi is MUSC 119(T) (=DSM 42174(T) = MCCC 1K00505(T)).
  2. Yong D, Ee R, Lim YL, Yu CY, Ang GY, How KY, et al.
    J Biotechnol, 2016 Jan 10;217:51-2.
    PMID: 26603120 DOI: 10.1016/j.jbiotec.2015.11.009
    Pandoraea thiooxydans DSM 25325(T) is a thiosulfate-oxidizing bacterium isolated from rhizosphere soils of a sesame plant. Here, we present the first complete genome of P. thiooxydans DSM 25325(T). Several genes involved in thiosulfate oxidation and biodegradation of aromatic compounds were identified.
  3. Yong D, Tee KK, Yin WF, Chan KG
    Front Microbiol, 2016;7:1606.
    PMID: 27790203
    To date, information on plasmid analysis in Pandoraea spp. is scarce. To address the gap of knowledge on this, the complete sequences of eight plasmids from Pandoraea spp. namely Pandoraea faecigallinarum DSM 23572(T) (pPF72-1, pPF72-2), Pandoraea oxalativorans DSM 23570(T) (pPO70-1, pPO70-2, pPO70-3, pPO70-4), Pandoraea vervacti NS15 (pPV15) and Pandoraea apista DSM 16535(T) (pPA35) were studied for the first time in this study. The information on plasmid sequences in Pandoraea spp. is useful as the sequences did not match any known plasmid sequence deposited in public databases. Replication genes were not identified in some plasmids, a situation that has led to the possibility of host interaction involvement. Some plasmids were also void of par genes and intriguingly, repA gene was also not discovered in these plasmids. This further leads to the hypothesis of host-plasmid interaction. Plasmid stabilization/stability protein-encoding genes were observed in some plasmids but were not established for participating in plasmid segregation. Toxin-antitoxin systems MazEF, VapBC, RelBE, YgiT-MqsR, HigBA, and ParDE were identified across the plasmids and their presence would improve plasmid maintenance. Conjugation genes were identified portraying the conjugation ability amongst Pandoraea plasmids. Additionally, we found a shared region amongst some of the plasmids that consists of conjugation genes. The identification of genes involved in replication, segregation, toxin-antitoxin systems and conjugation, would aid the design of drugs to prevent the survival or transmission of plasmids carrying pathogenic properties. Additionally, genes conferring virulence and antibiotic resistance were identified amongst the plasmids. The observed features in the plasmids shed light on the Pandoraea spp. as opportunistic pathogens.
  4. Yap PSX, Tan TS, Chan YF, Tee KK, Kamarulzaman A, Teh CSJ
    J Microbiol Biotechnol, 2020 Jul 28;30(7):962-966.
    PMID: 32627759 DOI: 10.4014/jmb.2006.06009
    Monitoring the mutation dynamics of human severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is critical in understanding its infectivity, virulence and pathogenicity for development of a vaccine. In an "age of mobility," the pandemic highlights the importance and vulnerability of regionalization and labor market interdependence in Southeast Asia. We intend to characterize the genetic variability of viral populations within the region to provide preliminary information for regional surveillance in the future. By analyzing 142 complete genomes from South East Asian (SEA) countries, we identified three central variants distinguished by nucleotide and amino acid changes.
  5. Wong SW, Ting YW, Yong YK, Tan HY, Barathan M, Riazalhosseini B, et al.
    Scand J Clin Lab Invest, 2021 Apr;81(2):147-159.
    PMID: 33528280 DOI: 10.1080/00365513.2021.1876245
    The pathogenesis involving non-alcoholic fatty liver disease (NAFLD) in the context of chronic HBV (CHB) virus infection requires to be understood for developing improved modalities of diagnosis and treatment. We retrospectively investigated the association between NAFLD and CHB virus infection in the context of liver fibrosis. Among the 522 consecutive CHB patients who underwent transient elastography between years 2013 and 2016, we studied 455 subjects in the current investigation. Controlled attenuation parameter (CAP) and liver stiffness measurement (LSM) scores were generally higher in patients with steatosis and fibrosis or cirrhosis. Antiviral treatment had significantly reduced the hepatitis B virus (HBV) viral load. Other liver function markers showed a significant positive correlation with both CAP and LSM scores. Plasma IL-13 was independently associated with increased CAP score where every increase of 1 unit of IL-13 was associated with an increase in CAP score by 0.98 unit. CCL11 was independently associated with LSM with every increase of CCL11 by a unit that, in turn, was associated with an increase of LSM score. We found that there was a high concurrence of NAFLD among patients with CHB virus infection. The presence of metabolic syndrome and chronic inflammation in CHB virus-infected patients were two independent factors that led to the progression of liver cirrhosis, with IL-13 playing the key role in linking the metabolic with the inflammatory components.
  6. Wong PL, Sii HL, P'ng CK, Ee SS, Yong Oong X, Ng KT, et al.
    Influenza Other Respir Viruses, 2020 05;14(3):286-293.
    PMID: 32022411 DOI: 10.1111/irv.12691
    BACKGROUND: Age is an established risk factor for poor outcomes in individuals with influenza-related illness, and data on its influence on clinical presentations and outcomes in the South-East Asian settings are scarce. The aim of this study was to determine the above among adults with influenza-related upper respiratory tract infection at a teaching hospital in Malaysia.

    METHODS: A retrospective case-note analysis was conducted on a cohort of 3935 patients attending primary care at the University Malaya Medical Centre, Malaysia from February 2012 till May 2014 with URTI symptoms. Demographics, clinical characteristics, medical and vaccination history were obtained from electronic medical records, and mortality data from the National Registration Department. Comparisons were made between those aged <25, ≥25 to <65 and ≥65 years.

    RESULTS: 470 (11.9%) had PCR-confirmed influenza virus infection. Six (1.3%) received prior influenza vaccination. Those aged ≥65 years were more likely to have ≥2 comorbidities (P 

  7. Tee KK, Kusagawa S, Li XJ, Onogi N, Isogai M, Hase S, et al.
    PLoS One, 2009;4(8):e6666.
    PMID: 19688091 DOI: 10.1371/journal.pone.0006666
    A growing number of emerging HIV-1 recombinants classified as circulating recombinant forms (CRFs) have been identified in Southeast Asia in recent years, establishing a molecular diversity of increasing complexity in the region. Here, we constructed a replication-competent HIV-1 clone for CRF33_01B (designated p05MYKL045.1), a newly identified recombinant comprised of CRF01_AE and subtype B. p05MYKL045.1 was reconstituted by cloning of the near full-length HIV-1 sequence from a newly-diagnosed individual presumably infected heterosexually in Kuala Lumpur, Malaysia. The chimeric clone, which contains the 5' LTR (long terminal repeat) region of p93JP-NH1 (a previously isolated CRF01_AE infectious clone), showed robust viral replication in the human peripheral blood mononuclear cells. This clone demonstrated robust viral propagation and profound syncytium formation in CD4+, CXCR4-expressing human glioma NP-2 cells, indicating that p05MYKL045.1 is a CXCR4-using virus. Viral propagation, however, was not detected in various human T cell lines including MT-2, M8166, Sup-T1, H9, Jurkat, Molt-4 and PM1. p05MYKL045.1 appears to proliferate only in restricted host range, suggesting that unknown viral and/or cellular host factors may play a role in viral infectivity and replication in human T cell lines. Availability of a CRF33_01B molecular clone will be useful in facilitating the development of vaccine candidates that match the HIV-1 strains circulating in Southeast Asia.
  8. Tee KK, Takebe Y, Kamarulzaman A
    Int J Infect Dis, 2009 May;13(3):307-18.
    PMID: 19010076 DOI: 10.1016/j.ijid.2008.09.005
    Over the past decade, a number of unique zoonotic and non-zoonotic viruses have emerged in Malaysia. Several of these viruses have resulted in significant morbidity and mortality to those affected and they have imposed a tremendous public health and economic burden on the state. Amongst the most devastating was the outbreak of Nipah virus encephalitis in 1998, which resulted in 109 deaths. The culling of more than a million pigs, identified as the amplifying host, ultimately brought the outbreak under control. A year prior to this, and subsequently again in 2000 and 2003, large outbreaks of hand-foot-and-mouth disease due to enterovirus 71, with rare cases of fatal neurological complications, were reported in young children. Three other new viruses - Tioman virus (1999), Pulau virus (1999), and Melaka virus (2006) - whose origins have all been linked to bats, have been added to the growing list of novel viruses being discovered in Malaysia. The highly pathogenic H5N1 avian influenza has also been detected in Malaysia with outbreaks in poultry in 2004, 2006, and 2007. Fortunately, no human infections were reported. Finally, the HIV/AIDS epidemic has seen the emergence of an HIV-1 recombinant form (CRF33_01B) in HIV-infected individuals from various risk groups, with evidence of ongoing and rapid expansion.
  9. Tee KK, Li XJ, Nohtomi K, Ng KP, Kamarulzaman A, Takebe Y
    J Acquir Immune Defic Syndr, 2006 Dec 15;43(5):523-9.
    PMID: 17031320
    A molecular epidemiological investigation was conducted among various risk populations (n = 184) in Kuala Lumpur, Malaysia, in 2003 to 2005, on the basis of nucleotide sequences of protease and reverse transcriptase regions. In addition to circulating HIV-1 strains, including CRF01_AE (57.1%), subtype B (20.1%), and subtype C (0.5%), we detected a candidate with a new circulating recombinant form (CRF). We determined four near-full-length nucleotide sequences with identical subtype structure from epidemiologically unlinked individuals of different risk and ethnic groups. In this chimera, two short subtype B segments were inserted into the gag-RT region in a backbone of CRF01_AE. The recombinant structure was distinct from previously identified CRF15_01B in Thailand. In agreement with the current HIV nomenclature system, this constitutes a novel CRF (CRF33_01B). The overall prevalence of CRF33_01B is 19.0% (35/184). Although the prevalence of CRF33_01B is particularly high among injecting drug users (42.0%, 21/50), it is also detected in a substantial proportion of homo-/bisexual males (18.8%, 3/16) and heterosexuals (9.8%, 9/92). Moreover, unique recombinant forms composed of CRF01_AE and subtype B that have a significant structural relationship with CRF33_01B were detected in 1.6% (3/184) of study subjects, suggesting an ongoing recombination process in Malaysia. This new CRF seems to be bridging viral transmission between different risk populations in this country.
  10. Tee KK, Pon CK, Kamarulzaman A, Ng KP
    AIDS, 2005 Jan 28;19(2):119-26.
    PMID: 15668536
    OBJECTIVES: To investigate the molecular epidemiology of HIV-1 and to screen for the emergence of intersubtype recombinants in Kuala Lumpur, Malaysia.

    DESIGN: A molecular epidemiology study was conducted among HIV-1 seropositive patients attending the University Malaya Medical Center (UMMC) from July 2003 to June 2004.

    METHODS: Protease (PR) and reverse transcriptase (RT) gene sequences were derived from drug resistance genotyping assay of 100 newly diagnosed or antiretroviral-naive patients. These were phylogenetically analysed to determine the subtypes and recombination breakpoint analyses were performed on intersubtype recombinants to estimate the recombination breakpoint(s).

    RESULTS: CRF01_AE predominated in Kuala Lumpur with 65% in both PR and RT genes. B subtype was detected at 14% and 12% in PR and RT genes, respectively. C subtype was present at 1% in both genes. Overall, the concordance of PR and RT genes in discriminating subtypes/circulating recombinant forms (CRF) was high at 96%. In this study, novel CRF01_AE/B intersubtype recombinants were detected at high prevalence (22%), including those isolates with subtype discordance. Thai variants of CRF01_AE and B subtype were involved in the genesis of these unique recombinant forms (URF). Interestingly, 19 CRF01_AE/B intersubtype recombinant isolates shared similar recombination breakpoints in both PR and RT genes. Several distinct URF were also identified.

    CONCLUSION: PR and RT genes can be utilized for subtype/CRF assessment with high degree of agreement, allowing concurrent surveillance of circulating HIV-1 subtypes with antiretroviral drug resistance genotyping tests. The emergence of highly identical CRF01_AE/B intersubtype recombinants suggests the possibility of the appearance of a new circulating recombinant form in Kuala Lumpur.

  11. Tee KK, Kamarulzaman A, Ng KP
    Med Microbiol Immunol, 2006 Jun;195(2):107-12.
    PMID: 16404607
    To assess the prevalence of major drug resistance mutations in antiretroviral (ARV)-treated patients with detectable viral load (VL) in Kuala Lumpur, Malaysia, genotypic resistance testing was performed among treated human immunodeficiency virus type 1 (HIV-1) patients attending the University Malaya Medical Center between July 2003 and November 2004. The reverse transcriptase (RT) and protease genes from 36 plasma samples with detectable VL were examined for major mutations associated with ARV resistance as reported by the International AIDS Society-USA Drug Resistance Mutations Group. The prevalence of patients with at least one major mutation conferring drug resistance to nucleoside RT inhibitors (NRTIs), non-NRTIs (NNRTIs) or protease inhibitors (PIs) was 77.8%. In the RT gene, the frequency of mutations associated with NRTIs and NNRTIs resistance was 52.8 and 63.9%, respectively, with M184V and K103N mutations being selected most frequently by these drugs. A patient with Q151M mutation complex was also detected. Twenty-two percent of the patients had mutations associated with PIs. The following pattern of prevalence of ARV-resistant HIV-1 variants was observed: NNRTI-resistant > NRTI-resistant > PI-resistant. The prevalence of major drug resistance mutations among ARV-treated patients with detectable VL is high in Kuala Lumpur. Genotypic drug resistance testing is therefore important for monitoring patients experiencing ARV regimen failure.
  12. Tee KK, Kamarulzaman A, Ng KP
    AIDS Res Hum Retroviruses, 2006 Feb;22(2):121-4.
    PMID: 16478392
    To assess the prevalence of mutations associated with drug resistance in antiretroviral-naive patients in Kuala Lumpur, Malaysia, genotypic resistance testing was conducted among drug-naive HIV-1 patients attending the University Malaya Medical Center (UMMC) between July 2003 and June 2004. Reverse transcriptase (RT) and protease genes of plasma virions were sequenced from 100 individuals. The majority of the patients were recently diagnosed. Codons 20-255 of the RT and 1-96 of the protease gene were examined for major and minor mutations associated with antiretroviral resistance reported by the International AIDS Society- USA (IAS-USA) Drug Resistance Mutations Group. The prevalence of patients with at least one major mutation conferring drug resistance was 1%, with only one patient having a Y181C amino acid substitution in the RT gene that confers high-level resistance to nevirapine and delavirdine. Minor mutations were detected in high prevalence in the protease gene. Amino acid substitutions I13V, E35D, and M36I were associated with CRF01_AE while L63P, V77I, and I93L were associated with subtype B. Baseline prevalence of major mutations associated with resistance to antiretroviral drugs was low among antiretroviral-naive HIV-1 patients, suggesting that routine drug resistance testing may be unnecessary for all individuals newly diagnosed with HIV or all patients beginning antiretroviral therapy.
  13. Tee KK, Saw TL, Pon CK, Kamarulzaman A, Ng KP
    AIDS Res Hum Retroviruses, 2005 Dec;21(12):1046-50.
    PMID: 16379608
    Earlier studies in the 1990s indicate that human immunodeficiency virus type 1 (HIV-1) subtype B has been the predominant subtype among injecting drug users (IDUs) in Malaysia. More recent studies performed between 2003 and 2004, however, show a high prevalence of unique CRF01_AE/B intersubtype recombinants among IDUs. To determine the subtype distribution among IDUs in Kuala Lumpur prior to the emergence of CRF01_AE/B intersubtype recombinants, the gag-pol or the reverse transcriptase gene was sequenced from IDUs who were diagnosed as HIV positive between 1993 and 2002. Subtype B was present at 50.0% followed by CRF01_AE/B recombinant at 41.7%, with more CRF01_AE/B recombinants detected between 2000 and 2002. All CRF01_AE/B recombinants shared similar recombination patterns. Interestingly, we found that this potential new candidate of circulating recombinant form (CRF) could have emerged as early as the mid-1990s. The results showed evidence of changing HIV-1 molecular epidemiology toward the predominance of CRF01_AE/B intersubtype recombinants among IDUs in Kuala Lumpur.
  14. Tee KK, Chan PQ, Loh AM, Singh S, Teo CH, Iyadorai T, et al.
    J Med Virol, 2023 Feb;95(2):e28520.
    PMID: 36691929 DOI: 10.1002/jmv.28520
    Pteropine orthoreovirus (PRV), an emerging bat-borne virus, has been linked to cases of acute respiratory infections (ARI) in humans. The prevalence, epidemiology and genomic diversity of PRV among ARI of unknown origin were studied. Among 632 urban outpatients tested negative for all known respiratory viruses, 2.2% were PRV-positive. Patients mainly presented with moderate to severe forms of cough, sore throat and muscle ache, but rarely with fever. Phylogenetic analysis revealed that over 90% of patients infected with the Melaka virus (MelV)-like PRV, while one patient infected with the Pulau virus previously found only in fruit bats. Human oral keratinocytes and nasopharyngeal epithelial cells were susceptible to clinical isolates of PRV, including the newly isolated MelV-like 12MYKLU1034. Whole genome sequence of 12MYKLU1034 using Nanopore technique revealed a novel reassortant strain. Evolutionary analysis of the global PRV strains suggests the continuous evolution of PRV through genetic reassortment among PRV strains circulating in human, bats and non-human primate hosts, creating a spectrum of reassortant lineages with complex evolutionary characteristics. In summary, the role of PRV as a common etiologic agent of ARI is evident. Continuous monitoring of PRV prevalence, pathogenicity and diversity among human and animal hosts is important to trace the emergence of novel reassortants.
  15. Tee KK, Bon AH, Chow WZ, Ng KT, Chan KG, Kamarulzaman A, et al.
    Genome Announc, 2017 Jun 29;5(26).
    PMID: 28663289 DOI: 10.1128/genomeA.00459-17
    We report here the first HIV-1 circulating recombinant form (CRF) complex identified among the blood donors in Malaysia. The CRF77_cpx mosaic genome consists of parental subtypes B', C, and CRF01_AE and is structurally related to CRF07_BC. The identification of CRF77_cpx underlines the genetic complexity and mobility of HIV-1 among the blood donors.
  16. Supian NI, Ng KT, Chook JB, Takebe Y, Chan KG, Tee KK
    BMC Infect Dis, 2021 May 17;21(1):446.
    PMID: 34001016 DOI: 10.1186/s12879-021-06148-x
    BACKGROUND: Coxsackievirus A21 (CVA21), a member of Enterovirus C from the Picornaviridae family, has been associated with respiratory illnesses in humans.

    METHODS: A molecular epidemiological investigation of CVA21 was conducted among patients presenting with acute upper respiratory illnesses in the ambulatory settings between 2012 and 2014 in Kuala Lumpur, Malaysia.

    RESULTS: Epidemiological surveillance of acute respiratory infections (n = 3935) showed low-level detection of CVA21 (0.08%, 1.4 cases/year) in Kuala Lumpur, with no clear seasonal distribution. Phylogenetic analysis of the new complete genomes showed close relationship with CVA21 strains from China and the United States. Spatio-temporal mapping of the VP1 gene determined 2 major clusters circulating worldwide, with inter-country lineage migration and strain replacement occurring over time.

    CONCLUSIONS: The study highlights the emerging role of CVA21 in causing sporadic acute respiratory outbreaks.

  17. Rhee SY, Blanco JL, Jordan MR, Taylor J, Lemey P, Varghese V, et al.
    PLoS Med, 2015 Apr;12(4):e1001810.
    PMID: 25849352 DOI: 10.1371/journal.pmed.1001810
    BACKGROUND: Regional and subtype-specific mutational patterns of HIV-1 transmitted drug resistance (TDR) are essential for informing first-line antiretroviral (ARV) therapy guidelines and designing diagnostic assays for use in regions where standard genotypic resistance testing is not affordable. We sought to understand the molecular epidemiology of TDR and to identify the HIV-1 drug-resistance mutations responsible for TDR in different regions and virus subtypes.

    METHODS AND FINDINGS: We reviewed all GenBank submissions of HIV-1 reverse transcriptase sequences with or without protease and identified 287 studies published between March 1, 2000, and December 31, 2013, with more than 25 recently or chronically infected ARV-naïve individuals. These studies comprised 50,870 individuals from 111 countries. Each set of study sequences was analyzed for phylogenetic clustering and the presence of 93 surveillance drug-resistance mutations (SDRMs). The median overall TDR prevalence in sub-Saharan Africa (SSA), south/southeast Asia (SSEA), upper-income Asian countries, Latin America/Caribbean, Europe, and North America was 2.8%, 2.9%, 5.6%, 7.6%, 9.4%, and 11.5%, respectively. In SSA, there was a yearly 1.09-fold (95% CI: 1.05-1.14) increase in odds of TDR since national ARV scale-up attributable to an increase in non-nucleoside reverse transcriptase inhibitor (NNRTI) resistance. The odds of NNRTI-associated TDR also increased in Latin America/Caribbean (odds ratio [OR] = 1.16; 95% CI: 1.06-1.25), North America (OR = 1.19; 95% CI: 1.12-1.26), Europe (OR = 1.07; 95% CI: 1.01-1.13), and upper-income Asian countries (OR = 1.33; 95% CI: 1.12-1.55). In SSEA, there was no significant change in the odds of TDR since national ARV scale-up (OR = 0.97; 95% CI: 0.92-1.02). An analysis limited to sequences with mixtures at less than 0.5% of their nucleotide positions—a proxy for recent infection—yielded trends comparable to those obtained using the complete dataset. Four NNRTI SDRMs—K101E, K103N, Y181C, and G190A—accounted for >80% of NNRTI-associated TDR in all regions and subtypes. Sixteen nucleoside reverse transcriptase inhibitor (NRTI) SDRMs accounted for >69% of NRTI-associated TDR in all regions and subtypes. In SSA and SSEA, 89% of NNRTI SDRMs were associated with high-level resistance to nevirapine or efavirenz, whereas only 27% of NRTI SDRMs were associated with high-level resistance to zidovudine, lamivudine, tenofovir, or abacavir. Of 763 viruses with TDR in SSA and SSEA, 725 (95%) were genetically dissimilar; 38 (5%) formed 19 sequence pairs. Inherent limitations of this study are that some cohorts may not represent the broader regional population and that studies were heterogeneous with respect to duration of infection prior to sampling.

    CONCLUSIONS: Most TDR strains in SSA and SSEA arose independently, suggesting that ARV regimens with a high genetic barrier to resistance combined with improved patient adherence may mitigate TDR increases by reducing the generation of new ARV-resistant strains. A small number of NNRTI-resistance mutations were responsible for most cases of high-level resistance, suggesting that inexpensive point-mutation assays to detect these mutations may be useful for pre-therapy screening in regions with high levels of TDR. In the context of a public health approach to ARV therapy, a reliable point-of-care genotypic resistance test could identify which patients should receive standard first-line therapy and which should receive a protease-inhibitor-containing regimen.

  18. Raihan R, Akbar SMF, Al Mahtab M, Khan MSI, Tabassum S, Tee KK, et al.
    Viral Immunol, 2020 09;33(7):530-534.
    PMID: 32513066 DOI: 10.1089/vim.2019.0198
    Hepatitis B virus (HBV) is a noncytopathic virus and billions of HBV-infected patients live uneventful lives and do not suffer from notable liver damage. However, HBV also causes progressive liver diseases characterized by hepatic inflammation, hepatic fibrosis, and liver cancer in millions of HBV-infected patients. The goal of this study was to evaluate the role of mutant HBV in HBV pathogenesis. In a cohort of 360 chronic HBV-infected patients, mutations at T1762/A1764 of HBV genome were detected in most of the patients with HBV-induced liver cirrhosis and hepatocellular carcinoma. To explore if mutations at T1762/A1764 of HBV genome has any role in progressive liver disease, peripheral blood mononuclear cells (PBMCs) and antigen-presenting dendritic cells (DCs) were isolated from five chronic hepatitis B (CHB) patients with mutations at T1762/A1764 and five comparable patients of CHB without mutations at T1762/A1764. DCs were pulsed with hepatitis B surface antigen (HBsAg). The levels of cytokines produced by PBMCs and DCs as well as nitrite production by DCs were evaluated. Significantly higher levels of interleukin-12, tumor necrosis factor-alpha, interferon-gamma, and transforming growth factor-beta were detected in cultures of PBMCs, DCs, and HBsAg-pulsed DCs from CHB patients with mutations at T1762/A1764 compared with those without mutations (p 
  19. Raihan R, Akbar SMF, Al Mahtab M, Takahashi K, Masumoto J, Tabassum S, et al.
    PLoS One, 2019;14(6):e0218744.
    PMID: 31251754 DOI: 10.1371/journal.pone.0218744
    The direct cytopathic effects of the hepatitis B virus (HBV) on subsequent liver damage are not fully understood in HBV-infected patients. However, associations between the prevalence of various HBV genotypes and the extent of liver damage have been reported from different parts of the world. The purpose of this study was to determine the distribution of HBV genotypes in patients with chronic HBV infection in Bangladesh, a country of 160 million people, of which approximately 3-6 million are chronically infected HBV patients. In addition, whole and partial genome sequencing of HBV was performed to evaluate the relationship between HBV mutations and genotypes. We found that 42% of the patients with low HBV DNA and normal levels of alanine aminotransferase (ALT) had HBV genotype D. In contrast, the HBV genotype C was dominant among patients with high HBV DNA levels (>2000 IU/ml) and elevated ALT and in patients with liver cirrhosis (LC) and hepatocellular carcinomas (HCC). Whole and partial genome sequences of HBV revealed that most patients with LC and HCC had HBV genotype C with mutations at the T1762/A1764 positions. It seems that Bangladesh represents a borderline country, situated within East Asia, which mainly consists of individuals with HBV genotypes B and C, whereas in the western parts of Asia, HBV genotypes A and D are prevalent. Bangladesh is, therefore, an excellent model for the comparison of the pathophysiology of three major HBV genotypes in a single population. The findings of this study suggest a possible association between HBV viral factors and the extent of liver damage in chronic HBV-infected patients.
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