Background: Helicobacter pylori is a Gram-negative bacillus that colonises only the mucus layer of the human stomach and is implicated in gastric diseases. Virulent H. pylori harbouring cag-pathogenicity island (cagPAI) which encodes... more
Background: Helicobacter pylori is a Gram-negative bacillus that colonises only the mucus layer of the human stomach and is implicated in gastric diseases. Virulent H. pylori harbouring cag-pathogenicity island (cagPAI) which encodes genes for type IV secretion system (T4SS) and CagA protein is one of the major virulence determinants involved in disease development. We examined the entire cagPAI genes in 95 H. pylori isolates from a multiracial population and examined the intactness of cagPAI region with histopathological scores of the gastric mucosa. Results: 95.8% of H. pylori isolates were cagPAI-positive with 23.2% having an intact cagPAI, whereas 72.6% had a partial/rearranged cagPAI. In our study, cag2 and cag4 were found to be significantly higher in H. pylori isolated from Malays, whereas cag4 was predominant in Chinese isolates. We also detected cag24 in significantly high proportion in isolates from the Malays and the Indians compared to the Chinese isolates. The intactnes...
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To find out the prevalence and antimicrobial susceptibility of Vibrio parahaemolyticus in seafoods and environmental sources. The study was carried out at the Center of Excellence for Food Safety Research, University Putra Malaysia;... more
To find out the prevalence and antimicrobial susceptibility of Vibrio parahaemolyticus in seafoods and environmental sources. The study was carried out at the Center of Excellence for Food Safety Research, University Putra Malaysia; Universiti Kebangsaan Malaysia; Medical Molecular Biology Institute; and University Kebansaan Malaysia Hospital, Malaysia between January 2006 and August 2008. One hundred and forty-four isolates from 400 samples of seafood (122 isolates) and seawater sources (22 isolates) were investigated for the presence of thermostable direct hemolysin (tdh+) and TDH-related hemolysin (trh+) genes using the standard methods. The E-test method was used to test the antimicrobial susceptibility. The study indicates low occurrence of tdh+ (0.69%) and trh+ isolates (8.3%). None of the isolates tested posses both virulence genes. High sensitivity was observed against tetracycline (98%). The mean minimum inhibitory concentration (MIC) of the isolates toward ampicillin incre...
Research Interests: Malaysia, Tropical Medicine, Infectious Diseases, Animals, Bacteria, and 11 moreSeafood, Microbial Sensitivity Tests, Molecular diagnosis of pathogens, Vibrio parahaemolyticus, Immunology And Biotechnology Of Parasites, Water Microbiology, Viral and Bacterial Pathogenesis, Bacteriology and Infectious Diseases, Tissue Culture and Hybridoma Technology, 9. Producing microbial antibiotics in vitro., and Medical and Health Sciences
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Gut dysbiosis has been associated with many chronic diseases, such as obesity, inflammatory bowel disease, and cancer. Gut dysbiosis triggers these diseases through the activation of the immune system by the endotoxins produced by gut... more
Gut dysbiosis has been associated with many chronic diseases, such as obesity, inflammatory bowel disease, and cancer. Gut dysbiosis triggers these diseases through the activation of the immune system by the endotoxins produced by gut microbiota, which leads to systemic inflammation. In addition to pre-/pro-/postbiotics, many natural products can restore healthy gut microbiota composition. Tocotrienol, which is a subfamily of vitamin E, has been demonstrated to have such effects. This scoping review presents an overview of the effects of tocotrienol on gut microbiota according to the existing scientific literature. A literature search to identify relevant studies was conducted using PubMed, Scopus, and Web of Science. Only original research articles which aligned with the review’s objective were examined. Six relevant studies investigating the effects of tocotrienol on gut microbiota were included. All of the studies used animal models to demonstrate that tocotrienol altered the gut...
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Background: The emergence of multidrug-resistant Helicobacter pylori has undermined eradication strategies to prevent the development of gastric cancer. This study was conducted to estimate the prevalence of secondary antibiotic... more
Background: The emergence of multidrug-resistant Helicobacter pylori has undermined eradication strategies to prevent the development of gastric cancer. This study was conducted to estimate the prevalence of secondary antibiotic resistance of H. pylori in urban multicultural areas in Malaysia. Methods: From January 2017 to December 2021, gastric biopsies from 218 patients with a history of H. pylori eradication failure were sent to our laboratory for antibiotic susceptibility testing. A minimal inhibitory concentration was determined for six antibiotics, namely metronidazole, clarithromycin, levofloxacin, amoxicillin, tetracycline, and rifampicin using the E-test method. Two multidrug-resistant H. pylori strains identified in this study were subjected to whole genome sequencing. Results: Eradication failure was observed to be significantly higher in the Malaysian Chinese patients than in the Malaysian Indian and Malay patients. H. pylori were successfully isolated from 51 patients (...
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New Delhi metallo-β-lactamase-1 (NDM-1) is a relatively recent carbapenemase enzyme that inactivates all β-lactam antibiotics with the exception of aztreonam. This study aims to ascertain the baseline prevalence and antibiotic... more
New Delhi metallo-β-lactamase-1 (NDM-1) is a relatively recent carbapenemase enzyme that inactivates all β-lactam antibiotics with the exception of aztreonam. This study aims to ascertain the baseline prevalence and antibiotic susceptibility patterns of NDM-1-producing Enterobacteriaceae in a tertiary medical center in Malaysia. Over a period of one year, all Enterobacteriaceae isolates from all clinical specimens with reduced susceptibility to at least one carbapenem and resistance to at least one third generation cephalosporin were subjected to antibiotic susceptibility testing by disk diffusion and molecular detection of the NDM-1 gene by single-target PCR followed by gel electrophoresis. A total of 13,098 Enterobacteriaceae isolates were screened and 63 (0.48%) had reduced susceptibility to at least one carbapenem. Of this 63, 18 (29%) were NDM-1-positive. Of this 18, 16 (89.0%) were Klebsiella pneumoniae, one (5.5%) was Escherichia coli and one (5.5%) was Klebsiella ornithinoly...
Research Interests: Microbiology, Biology, Medicine, Humans, Pubmed, and 11 moreMicrobial genetic and drug resistance, Enterobacteriaceae, Antibiotics, Prevalence, Microbial Sensitivity Tests, Aztreonam, Cross Sectional Studies, Klebsiella Oxytoca, Beta Lactamases, Klebsiella pneumoniae, and reverse transcriptase polymerase chain reaction
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Helicobacter pylori strains secrete a vacuolating cytotoxin (VacA), plays an important role for the development of peptic ulcer disease and gastro-duodenal diseases. vacA gene is responsible to regulate the activity of the vacuolating... more
Helicobacter pylori strains secrete a vacuolating cytotoxin (VacA), plays an important role for the development of peptic ulcer disease and gastro-duodenal diseases. vacA gene is responsible to regulate the activity of the vacuolating cytotoxin. The objective of this study was molecular detection of vacA gene and observes the vacuolating activity on human gastric adenocarcinoma (AGS) cells. H. pylori vacA gene was determined by polymerase chain reaction. Vacuolation activity of VacA toxin in broth culture filtrates was assessed in AGS cells and quantified by neutral uptake assay. Different concentration dosages of VacA and incubation time were used in the measurement of the vacuolating activity on AGS cells. The results showed that VacA toxin could stimulate vacuolating activity on AGS cells with minimum concentration 1.0 μg/ml from both of s1m1 and s1m2 alleles (vacA gene). The toxin produced optimal reaction at 5.0 μg/ml with significant differences observed between the alleles. T...
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Serratia marcescens is a well-known cause of nosocomial infections and outbreaks, particularly in immunocompromised patients with severe underlying disease. An outbreak due to S. marcescens infection was detected from 13 to 22 February... more
Serratia marcescens is a well-known cause of nosocomial infections and outbreaks, particularly in immunocompromised patients with severe underlying disease. An outbreak due to S. marcescens infection was detected from 13 to 22 February 2001 at the intensive care unit (ICU) of our institution. We used pulsed-field gel electrophoresis (PFGE) typing to analyse the outbreak strains involved. A total of 25 isolates were included in this study: 12 isolates from infected patients, nine isolates from insulin solution, one isolate from sedative solution (midazolam and morphine infusion) and one isolate from frusemide solution. Two isolates from other wards which were epidemiologically-unrelated were also included. The S. marcescens from patients, insulin solution and sedative solution showed an identical PFGE fingerprint pattern. The isolate from the frusemide solution had a closely-related PFGE pattern to the outbreak strain with one band difference. Attempts were made in the present study ...
Research Interests: Microbiology, Medicine, Disease Outbreaks, Humans, Pubmed, and 10 moreDNA fingerprinting, Intensive Care Unit, Serratia marcescens, Pulsed field gel electrophoresis (PFGE), Microbial Sensitivity Tests, Gel electrophoresis, Intensive Care Units, Outbreak, Medical and Health Sciences, and Cross Infection
Research Interests: Microbiology, Biology, Helicobacter pylori, Medicine, Antibiotic Resistance, and 15 moreBiological Sciences, Humans, Mutation, Female, Male, Clarithromycin, Aged, Middle Aged, Adult, Microbial Sensitivity Tests, Base Sequence, Metronidazole, Cohort Studies, Molecular Sequence Data, and Medical and Health Sciences
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Research Interests: Microbiology, Molecular Biology, Medical Microbiology, Biology, Medicine, and 11 morePlant diseases, Coinfection, Journal of Virological Methods, Time Factors, Cost Benefit Analysis, Vitis, Multiplex, Sensitivity and Specificity, Viral Load, real time polymerase chain reaction, and multiplex polymerase chain reaction
Antibiotic resistance is increasing worldwide, and it has been regarded as the main factor reducing the efficacy ofHelicobacter pyloritherapy. The aim of this study was to determine the phenotype and genotype of antibiotic-resistant... more
Antibiotic resistance is increasing worldwide, and it has been regarded as the main factor reducing the efficacy ofHelicobacter pyloritherapy. The aim of this study was to determine the phenotype and genotype of antibiotic-resistant strains ofH. pyloriin the Malaysian population and to evaluate the impact of antibiotic resistance to eradication outcome. One hundred and sixty-oneH. pyloriisolates were analysed in this study. Metronidazole, clarithromycin, fluoroquinolone, amoxicillin and tetracycline susceptibilities were determined by Etest. PCR followed by DNA sequencing was carried out to determine mutations. The medical records of the patients infected with resistant strains were reviewed to determine the eradication outcome. Metronidazole resistance was encountered in 36.6 % ofH. pyloriisolates, whereas clarithromycin and fluoroquinolone resistance was observed in 1.2 and 1.9 % of isolates, respectively. All strains tested were susceptible to amoxicillin and tetracycline. Frame...
Research Interests: Microbiology, Medical Microbiology, Biology, Helicobacter pylori, Adolescent, and 15 moreMedicine, Biological Sciences, Humans, Mutation, Female, Male, Polymerase Chain Reaction, Clarithromycin, Aged, Middle Aged, Adult, Amoxicillin, Microbial Sensitivity Tests, Metronidazole, and Medical and Health Sciences
The objective of this study was to compare the rates of bacterial contamination of expressed breast milk (EBM) obtained by manual expression and breast pumps in mothers of very low birthweight (VLBW) infants (<1501 g). This was a... more
The objective of this study was to compare the rates of bacterial contamination of expressed breast milk (EBM) obtained by manual expression and breast pumps in mothers of very low birthweight (VLBW) infants (<1501 g). This was a randomized, controlled study carried out on 28 mothers of such babies and 92 specimens of EBM were collected: 41 specimens from 13 mothers assigned to the manual group and 51 specimens from 15 mothers in the breast-pump group. EBM was cultured quantitatively by the Miles and Misra method. Breast milk expressed by breast pumps (86.3% or 44/51 specimens) had a significantly higher rate of bacterial contamination than milk expressed by the manual method (61.0% or 25/41 specimens) (P= 0.005). When breast milk was expressed in the hospital, there was no significant difference in contamination rates between the two methods. When breast milk was expressed at home, the rates of bacterial contamination by staphylococci (P= 0.003) and Gram-negative bacilli (P= 0.002) were significantly higher in the breast-pump group than the manual group. In conclusion, the rate of bacterial contamination of EBM of mothers of VLBW infants was high, especially when EBM was obtained by the breast pump or when expression was carried out at home.
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Background and aim: Polymorphisms of Helicobacter pylori cagA and vacA genes do exist and may contribute to differences in H. pylori infection and gastroduodenal diseases among races in the Malaysian population. This study was conducted... more
Background and aim: Polymorphisms of Helicobacter pylori cagA and vacA genes do exist and may contribute to differences in H. pylori infection and gastroduodenal diseases among races in the Malaysian population. This study was conducted to characterize the polymorphisms in H. pylori cagA and vacA in Malaysian population.Methods: A total of 110 H. pylori isolates were genotyped by PCR and sequenced for cagA and PCR‐RFLP for vacA.Results: East Asian cagA was predominantly detected (64.5%), whereas vacA s1m1 and s1m2 alleles were detected in 60.9 and 37.3% of strains, respectively. A statistical association between cagA type with patients’ ethnicity (p < .0001) and age group >50 years old (p = .027) was identified. vacA alleles showed significant association with age group >50 years old (p = .017) and increased neutrophil activity in gastric mucosa (p = .028 and p = .016 for moderate and marked activity, respectively). Further identification of vacA polymorphism revealed th...
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Research Interests: Microbiology, Epidemiology, Malaysia, Biology, Medicine, and 11 moreMolecular Epidemiology, Humans, Staphylococcus aureus, Research article, TYPING, Public health systems and services research, Methicillin Resistance, Pulsed field gel electrophoresis (PFGE), Methicillin Resistant Staphylococcus Aureus, Cross Infection, and Staphylococcal infections
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Alternative therapies and vaccination are essential to combat the emergence of multidrug-resistant Helicobacter pylori and to prevent the development of gastroduodenal diseases. This review aimed to systematically review recent studies on... more
Alternative therapies and vaccination are essential to combat the emergence of multidrug-resistant Helicobacter pylori and to prevent the development of gastroduodenal diseases. This review aimed to systematically review recent studies on alternative therapies, i.e., probiotics, nanoparticles, and natural products from plants, as well as recent progress in H. pylori vaccines at the preclinical stage. Articles published from January 2018 to August 2022 were systematically searched using PubMed, Scopus, Web of Science, and Medline. After the screening process, 45 articles were eligible for inclusion in this review. Probiotics (n = 9 studies) and natural products from plants (n = 28 studies) were observed to inhibit the growth of H. pylori, improve immune response, reduce inflammation, and reduce the pathogenic effects of H. pylori virulence factors. Natural products from plants also showed anti-biofilm activity against H. pylori. However, clinical trials of natural products from plant...
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Just over a million people died globally in 2019 due to antibiotic resistance caused by ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and... more
Just over a million people died globally in 2019 due to antibiotic resistance caused by ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species). The World Health Organization (WHO) also lists antibiotic-resistant Campylobacter and Helicobacter as bacteria that pose the greatest threat to human health. As it is becoming increasingly difficult to discover new antibiotics, new alternatives are needed to solve the crisis of antimicrobial resistance (AMR). Bacteria commonly found in complex communities enclosed within self-produced matrices called biofilms are difficult to eradicate and develop increased stress and antimicrobial tolerance. This review summarises the role of antimicrobial peptides (AMPs) in combating the silent pandemic of AMR and their application in clinical medicine, focusing on both the advantages and disadvantages of AMPs as antibiofilm agents. It is known that ma...
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The emergence of multidrug-resistant H. pylori poses a public healthcare threat, particularly in low- and middle-income countries. Recently, the World Health Organization has classified clarithromycin-resistant H. pylori as high priority... more
The emergence of multidrug-resistant H. pylori poses a public healthcare threat, particularly in low- and middle-income countries. Recently, the World Health Organization has classified clarithromycin-resistant H. pylori as high priority in the research and discovery of novel antibiotics. This study was aimed to systematically review the prevalence of primary antibiotic resistance in H. pylori in Southeast Asian countries (SEAC) and to review current studies of antimicrobial peptides against H. pylori. We systematically searched through electronic databases of studies conducted on antimicrobial resistance of H. pylori in SEA countries. Furthermore, we searched articles that conducted studies on antimicrobial peptides, naturally occurring host’s defense molecules, against H. pylori. After a series of screening processes, 15 studies were included in our systematic review. Our analysis revealed that primary resistance of H. pylori to metronidazole, clarithromycin, and levofloxacin were...
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Conference Proceedings 2nd Asia Pacific Pharmacy Education (PharmED) Workshop ISSN 2045-080X Vol. 3, Issue 1, 2012 MOLECULAR ANALYSIS AND GENETIC STUDIES ON VIBRIO PARAHAEMOLYTICUS ISOLATED FROM SEAFOOD AND COSTAL WATER IN MALAYSIA Saleh... more
Conference Proceedings 2nd Asia Pacific Pharmacy Education (PharmED) Workshop ISSN 2045-080X Vol. 3, Issue 1, 2012 MOLECULAR ANALYSIS AND GENETIC STUDIES ON VIBRIO PARAHAEMOLYTICUS ISOLATED FROM SEAFOOD AND COSTAL WATER IN MALAYSIA Saleh Mutahar Y. Al-Othrubi1, Alfizah Hanafiah1, Son Radu2, Ramelah Muhamed1 1UKM Centre for Graduate Management and UKM Hospital-Clinical Microbiology; Malaysia, 2UPM, the Centre of Excellence for Food Safety Research (CEFSR), Faculty of Food Sciences and Biotechnology, Malaysia ABSTRACT Vibrio parahaemolyticus is a gram negative curved-rod bacterium that is widely distributedVibrio parahaemolyticus is a gram negative curved-rod bacterium that is widely distributed in the marine environment. This organism is frequently isolated from raw seafoods, particularly shellfish. Consumption of raw or undercooked seafood contaminated with V. parahaemolyticus may lead to development of acute gastroenteritis characterised by diarrhoea, headache, vomiting, nausea, an...
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Bacterial culture and biochemical testing (CBtest) have been the cornerstone of pathogen identification in the diagnostic microbiology laboratory. With the advent of Sanger sequencing and later, next-generation sequencing, 16S rRNA... more
Bacterial culture and biochemical testing (CBtest) have been the cornerstone of pathogen identification in the diagnostic microbiology laboratory. With the advent of Sanger sequencing and later, next-generation sequencing, 16S rRNA next-generation sequencing (16SNGS) has been proposed to be a plausible platform for this purpose. Nevertheless, usage of the 16SNGS platform has both advantages and limitations. In addition, transition from the traditional methods of CBtest to 16SNGS requires procurement of costly equipment, timely and sustainable maintenance of these platforms, specific facility infrastructure and technical expertise. All these factors pose a challenge for middle-income countries, more so for countries in the lower middle-income range. In this review, we describe the basis for CBtest and 16SNGS, and discuss the limitations, challenges, advantages and future potential of using 16SNGS for bacterial pathogen identification in diagnostic microbiology laboratories of middle-...
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Research Interests: Microbiology, Biology, Helicobacter pylori, Medicine, Virulence, and 3 moreGenotype, CagA, and Gastric mucosa
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ABSTRACTH. pyloriinfection is a global public health problem associated with some gastrointestinal diseases in children, especially in developing countries, since prevalence ofH. pyloriis low in the developed world. Both noninvasive... more
ABSTRACTH. pyloriinfection is a global public health problem associated with some gastrointestinal diseases in children, especially in developing countries, since prevalence ofH. pyloriis low in the developed world. Both noninvasive (stool antigen test, urea breath test, and blood test) and invasive (histology, rapid urease test, and microbiological culture) tests have been utilized to detectH. pyloriinfection. However, a single test is not reliable enough and does not provide accurate enough data to determineH. pyloriinfection among children. Risk factors ofH. pyloriinfection in children were related to ethnicities, household properties, geographic location, living conditions, water sources, type of housing, presence/absence of sewage systems, and garbage collection within the living environment. These risk factors were usually associated with the socioeconomic status of the family. This review article aims to determine the gaps in the knowledge of the epidemiology, risk factors, a...
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Multidrug-resistant (MDR) Acinetobacter baumannii has increasingly emerged as an important nosocomial pathogen. The aim of this study was to determine the resistance profiles and genetic diversity in A. baumannii clinical isolates in a... more
Multidrug-resistant (MDR) Acinetobacter baumannii has increasingly emerged as an important nosocomial pathogen. The aim of this study was to determine the resistance profiles and genetic diversity in A. baumannii clinical isolates in a tertiary medical center in Malaysia. The minimum inhibitory concentrations of carbapenems (imipenem and meropenem), cephalosporins (ceftazidime and cefepime), and ciprofloxacin were determined by E-test. PCR and sequencing were carried out for the detection of antibiotic resistance genes and mutations. Clonal relatedness among A. baumannii isolates was determined by REP-PCR. Sequence-based typing of OXA-51 and multilocus sequence typing were performed. One hundred twenty-five of 162 (77.2%) A. baumannii isolates had MDR phenotype. From the 162 A. baumannii isolates, 20 strain types were identified and majority of A. baumannii isolates (66%, n = 107) were classified as strain type 1 and were positive for ISAba1-blaOXA-23 and ISAba1-blaADC and had mutat...
Research Interests: Malaysia, Biology, Medicine, Gene expression, Biological Sciences, and 15 moreHumans, Cephalosporins, Dna Gyrase, Isoenzymes, Carbapenems, Microbial Sensitivity Tests, Acinetobacter baumannii, Ciprofloxacin, Acinetobacter Infections, Beta Lactamases, microbial drug resistance, meropenem, Cefepime, Medical and Health Sciences, and Cross Infection
Research Interests: Histology, Helicobacter pylori, Adolescent, Medicine, Biopsy, and 15 moreHumans, Female, Feasibility Studies, Male, Aged, Middle Aged, Adult, Reproducibility of Results, Host Pathogen Interactions, Sensitivity and Specificity, Stomach, Urease, Medical and Health Sciences, multiplex polymerase chain reaction, and rapid urease test
Comprehensive immunophenotyping cluster of differentiation (CD) antigens in gastric adenocarcinoma, specifically between Helicobacter pylori-infected and -uninfected gastric cancer patients by using DotScan(™) antibody microarray has not... more
Comprehensive immunophenotyping cluster of differentiation (CD) antigens in gastric adenocarcinoma, specifically between Helicobacter pylori-infected and -uninfected gastric cancer patients by using DotScan(™) antibody microarray has not been conducted. Current immunophenotyping techniques include flow cytometry and immunohistochemistry are limited to the use of few antibodies for parallel examination. We used DotScan(™) antibody microarray consisting 144 CD antibodies to determine the distribution of CD antigens in gastric adenocarcinoma cells and to elucidate the effect of H. pylori infection toward CD antigen expression in gastric cancer. Mixed leukocytes population derived from gastric adenocarcinoma patients were immunophenotyped using DotScan(™) antibody microarray. AGS cells were infected with H. pylori strains and cells were captured on DotScan(™) slides. Cluster of differentiation antigens involved in perpetuating the tolerance of immune cells to tumor cells was upregulated in gastric adenocarcinoma cells compared to normal cells. CD279 which is essential in T cells apoptosis was found to be upregulated in normal cells. Remarkably, H. pylori-infected gastric cancer patients exhibited upregulated expression of CD27 that important in maintenance of T cells. Infection of cagA+ H. pylori with AGS cells increased CD antigens expression which involved in cancer stem cell while cagA- H. pylori polarized AGS cells to express immune-regulatory CD antigens. Increased CD antigens expression in AGS cells infected with cagA+ H. pylori were also detected in H. pylori-infected gastric cancer patients. This study suggests the tolerance of immune system toward tumor cells in gastric cancer and distinct mechanisms of immune responses exploited by different H. pylori strains.