Seroprevalence of Hepatitis B and C in Healthy Malaysian Adults: A Preliminary Report

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Prerequisite Evaluation of Anaerobic Settings for Gut Microbiome Functional Studies

Colon cancer-associated gut bacteria were mostly identified via next-generation sequencing in gut microbiome profiling studies. Anaerobic culture systems can be used to culture colon cells with these gut bacteria to further confirm the tumorigenic properties of these bacteria. Nevertheless, it is unclear how colon cells will grow in an anaerobic environment, as most cells are cultured aerobically. Therefore, we investigated the survival and viability of HT-29, a colon cancer cell line in an anaerobic culture system, and compared it to the usual culture condition in an aerobic setup. Interestingly, we found that HT-29 was able to grow in the anaerobic setup. Its viability was similar for both culture conditions, with only a slower growth rate observed in the anaerobic setup. Furthermore, gene expression studies showed that the cells were not under severe anaerobic stress even when exposed to the oxygen-deprived environment.This study provided results on some baseline parameters of an anaerobic colon cell culture system, and will be useful for journal readers who wish to investigate functional properties of anaerobic bacteria

Dengue epidemic in Malaysia: Not a predominantly urban disease anymore

BACKGROUND: Dengue infection has been an important and serious public health concern in Malaysia ever since its first reported case here in 1902. Nevertheless, to our knowledge, no nationwide investigation has been carried out to determine the actual magnitude of dengue endemicity in the Malaysian population. In this study, we describe a cross sectional seroepidemiology study of dengue IgG seroprevalence in the Malaysian adult population. FINDINGS: From 1000 subjects (35-74 years old), 91.6% subjects were found to be dengue seropositive. Age is found to be a significant risk factor associated with dengue seroposivity, where the seroprevalence increased with every 10 year increase in age. Nevertheless, gender and ethnicity did not have an effect. Interestingly, there were similar seroprevalence rates between urban and rural samples, showing that dengue is presently not confined to urban areas in Malaysia. CONCLUSIONS: High dengue IgG seropositivity found in the population is an indication that dengue might be endemic in Malaysia for a long time into the future. Public awareness, proper vector control and vigilant surveillance are critical to keep the infection rates low and to prevent outbreaks

The heterogeneic distribution of Helicobacter pylori cag pathogenicity island reflects different pathologies in multiracial Malaysian population

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

Impact of reduced vancomycin susceptibility on the therapeutic outcome of MRSA bloodstream infections

<p>Abstract</p> <p>Background</p> <p>The aim of this study was to determine whether clinical outcome of patients with methicillin-resistant <it>Staphylococcus aureus </it>(MRSA) bacteraemia was correlated with vancomycin susceptibility of the corresponding strains.</p> <p>Methods</p> <p>A retrospective study on MRSA bacteraemia was performed at a teaching hospital between January 1998 and October 2005 by linking vancomycin susceptibility profiles of patients' isolates with hospitalization data.</p> <p>Results</p> <p>A total of 20 out of 209 MRSA bacteraemia patients were treated with vancomycin for at least 5 days with adequate trough levels, and fulfilled the study's inclusion and exclusion criteria. Twenty-two <it>S. aureus </it>isolates from these patients' blood cultures were identified as MRSA, including two <it>hetero</it>-VISA from separate patients and two VISA with vancomycin MIC of 4 mg/L from one patient. Between patients who showed 'good' vancomycin response and patients who did not, there was a significant difference (p < 0.01) in their corresponding MRSAs' vancomycin susceptibility expressed by 'area under curve' (AUC) of population analysis. Significant correlations were found between AUC and initial vancomycin therapeutic response parameters of 'days till afebrile' (<it>r </it>= 0.828, p < 0.01) and 'days till CRP ≦ 30% of maximum' (<it>r </it>= 0.627, p < 0.01)</p> <p>Conclusion</p> <p>Our study results caution healthcare personnel that early consideration should be given to cases with a poor vancomycin treatment response that could signify the involvement of MRSA with reduced susceptibility to vancomycin.</p

Highly porous chitosan beads embedded with silver-graphene oxide nanocomposites for antibacterial application

Incorporation of silver nanomaterial into polymer matrix can further accomplished their potential usage in real life applications. In our previous study, silver nanoparticles (AgNPs) and silver-graphene oxide nanocomposites (AgGO) were prepared via a rapid microwave-assisted method. Hereby, the as-synthesized AgNPs or AgGO was dispersed in a chitosan solution. Subsequently, the resultant mixture solution was further coagulated in a coagulation bath containing sodium hydroxide via a neutralization process. This resulted in the formation of spherical-shaped chitosan beads. The structure of the beads showed that the chitosan beads embedded with AgGO exhibited a more porous structure as compared to the plain chitosan beads. Furthermore, the chitosan beads containing AgNPs or AgGO were tested for their antibacterial activity against Escherichia coli and Staphylococcus aureus. The antibacterial results indicated that the silver nanomaterial contained chitosan beads could effectively inhibit the growth of both E. coli and S. aureus as compared to the bare chitosan beads. The produced chitosan nanocomposite envisioned that can be potentially employed for water disinfection purpose

Toxin gene profiling of methicillin-susceptible Staphylococcus aureus (MSSA) isolated from a Malaysian teaching hospital

Entero- and exfoliative toxin gene profiling of 237 methicillin-susceptible Staphylococcus aureus (MSSA) isolated from Universiti Kebangsaan Malaysia Medical Centre (UKMMC) were carried out via PCR amplification. Among the tested toxin genes, sei was found to be the most prevalent (54.9%)

Functional analysis of cag pathogenicity island diversity in helicobacter pylori isolated from multi-ethnic patients in Malaysia

cagPAI is an important pathogenic marker contributing to disease severity caused by H. pylori infection, encoding proteins for type four secretion systems (T4SS) and the pro-inflammatory cytokines (IL-8) induction in infected host. The heterogeneity of cagPAI genes results in different clinical outcomes in H. pylori infection. The aim of this study was to investigate the functional diversity of cagPAI genes in clinical H. pylori strains isolated from patients with gastroduodenal diseases. Among the isolates investigated, 6 out of 27 (22.2%) harbor intact cagPAI, 3 strains (11.1%) have complete absence of cagPAI, and 18 strains (66.7%) contain a partially deleted island. IL-8 concentration is observed significantly higher among cagPAI-positive isolates (P = 0.045). Of note, IL-8 secretion in the gastric cells infected with H. pylori strains isolated from Malay patients was significantly higher than the gastric cells infected with the strains from non-Malay patients (P = 0.046). The secretion of IL-8 appears in similarly high among intact and partially deleted cagPAI isolates. East Asian cagA isolates induce a notably higher level of IL-8 than that of Western cagA. Inflammatory activities are observed and IL-8 concentration in the milder stage was found in significantly higher quantities than in the severe stage (P = 0.027). The ‘hummingbird’ phenotype was observed to cause severe effects in infected cells with cagPAI-intact H. pylori. The genetic variability of cagPAI isolates from multi-ethnicity patients may have unique implications for disease outcomes with respect to proinflammatory secretion

Heterogeneous vancomycin-intermediate Staphylococcus aureus (HVISA) at a tertiary hospital in Malaysia

Methicillin-resistant Staphylococcus aureus remains a global problem. The emergence of reduced susceptibility to Vancomycin in MRSA strains, leads to treatment failure and prolonged hospital stay. Therefore, we aimed to determine the strains with reduced susceptibility among MRSA clinical isolates. S. aureus isolates were collected from identified clinical samples. Antibiotic susceptibility was tested using the Kirby-Bauer method. MRSA strains were confirmed using PCR for mecA gene and subjected to the Epsilometer test (Etest®) for determination of Vancomycin minimum inhibitory concentration (MIC). Isolates with intermediate or reduced susceptibility were subjected to broth microdilution (BMD) and further confirmed by population analysis-area under curve (PAP-AUC) testing. Disc diffusion tests showed that all isolates (n = 105; 100%) were susceptible to Rifampicin, followed by Trimethoprim/Sulfamethoxazole. Meanwhile, a high resistance rate was demonstrated against Penicillin (n = 93; 88.6%). Among all isolates, only 26.0% (n = 27) were MRSA. According to the Vancomycin MIC value by Etest®, only two strains (A3, A106) had intermediate susceptibility, and one strain (A30) had reduced susceptibility to Vancomycin (MIC 3 μg/mL). No susceptibility to Vancomycin was identified among strains using the BMD method. According to the PAP-AUC method, it was confirmed that strain A3 was a heterogeneous VISA strain. Vancomycin Etest®, is a reliable screening test for VISA detection. Vancomycin BMD result was not in agreement with the Vancomycin Etest® result. PAP-AUC, the gold standard test used to detect Vancomycin resistance, should be conducted whenever possible for further confirmation and epidemiological record

Development of Corynebacterium glutamicum as staphylococcal-targeting chassis via the construction of autoinducing peptide (AIP)-responsive expression system

Despite increasing reports of antimicrobial activities of commensal and non-pathogenic bacteria such as Corynebacterium spp., previous studies on bioengineered therapeutics traditionally employed probiotics and food-grade bacteria which limits further advancements into microbial therapeutics research. In this study, Corynebacterium glutamicum, a generally recognised as safe (GRAS) and model bacterium was employed as a new chassis for the development of bioengineered corynebacterial chassis tailored towards Staphylococcus sp. via autoinducer peptide (AIP)-based quorum sensing (QS) interactions. To develop C. glutamicum as a staphylococcal-targeting chassis, the bacteria were transformed with the pResponse plasmid harboring AIP-responding accessory regulatory proteins agrAC and red fluorescent protein (RFP) genes under the control of the PaceA and P3 promoter, respectively, which was expected to stimulate the production of fluorescence signals in the presence of AIPs. Fluorescence activity of the C. glutamicum pResponse strain was compared to control C. glutamicum pRFP strain containing only the P3-RFP gene without the agrAC gene cassette. Using AIP-I as the input biomolecule, C. glutamicum pResponse strain fluoresced under different concentrations of AIP-I whereas no fluorescence was observed in the control C. glutamicum pRFP strain. When tested with S. aureus culture supernatant, the pResponse strain exhibited increasing fluorescence over the incubation period with the highest fluorescence signal of 183 relative fluorescence units (R.F.U) was observed at the 48 h point thereby demonstrating a functional QS-responsive protein expression system in bioengineered C. glutamicum. These findings demonstrated the feasibility and promising potential of developing bioengineered C. glutamicum as a staphylococcalresponsive and -targeting chassis