Displaying publications 1 - 20 of 40 in total

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  1. Ultrasensitive pathogen detection with a rolling circle amplification-empowered multiplex electrochemical DNA sensor
    Yeap CSY, Chaibun T, Lee SY, Zhao B, Jan Y, La-O-Vorakiat C, et al.
    Chem Commun (Camb), 2021 Nov 16;57(91):12155-12158.
    PMID: 34726213 DOI: 10.1039/d1cc05181d
    We report a highly sensitive and selective multiplex assay by empowering an electrochemical DNA sensor with isothermal rolling circle amplification. The assay could simultaneously detect and discriminate three common entero-pathogens in a single reaction, with femtomolar sensitivity. It is useful for field- or resource-limited settings.
    Matched MeSH terms: Shigella flexneri/isolation & purification*
  2. Development of rapid gold nanoparticles based lateral flow assays for simultaneous detection of Shigella and Salmonella genera
    Yahaya ML, Zakaria ND, Noordin R, Abdul Razak K
    Biotechnol Appl Biochem, 2021 Oct;68(5):1095-1106.
    PMID: 32935878 DOI: 10.1002/bab.2029
    Salmonella and Shigella genera are common pathogens that contaminate foods and beverages. Lateral flow assays (LFA) are commonly used to detect these pathogens. However, most of the developed LFAs are for single detection. Simultaneous detection of pathogens is required to reduce cost and time. In this work, 40 nm gold nanoparticles (AuNPs) were synthesized using the seeding growth method as labeling agent. The AuNPs were characterized and conjugated with mouse anti-Gram negative endotoxin antibody. The nitrocellulose membrane HF135 was immobilized with anti-mouse IgG antibody as a control line and two separate test lines with either anti-Shigella or anti-Salmonella antibody, respectively. Color intensity of test lines was observed for positive samples. A milk sample was used as proof of concept to mimic actual contamination. The limit of detection of the LFA was 3.0 × 106 CFU/mL for multiplex detection of Shigella flexneri and Salmonella Typhi and for both single detections. The result was comparable with the enzyme-linked immunosorbent assay (ELISA) analysis. The produced LFA could differentiate between Shigella flexneri, Shigella boydii, Salmonella Enteritidis, and Salmonella Typhi. The developed LFA was able to identify Shigella flexneri and Salmonella Typhi with good sensitivity in milk samples, thus, beneficial to ensure the safety of food before entering the market.
    Matched MeSH terms: Shigella/isolation & purification*
  3. Fulltext Chemical Profile, Antioxidant Properties and Antimicrobial Activities of Malaysian Heterotrigona itama Bee Bread
    Suleiman JB, Mohamed M, Abu Bakar AB, Nna VU, Zakaria Z, Othman ZA, et al.
    Molecules, 2021 Aug 15;26(16).
    PMID: 34443531 DOI: 10.3390/molecules26164943
    The aim of the study was to determine the chemical profile, antioxidant properties and antimicrobial activities of Heterotrigona itama bee bread from Malaysia. The pH, presence of phytochemicals, antioxidant properties, total phenolic content (TPC) and total flavonoid content (TFC), as well as antimicrobial activities, were assessed. Results revealed a decrease in the pH of bee bread water extract (BBW) relative to bee bread ethanolic extract (BBE) and bee bread hot water extract (BBH). Further, alkaloids, flavonoids, phenols, tannins, saponins, terpenoids, resins, glycosides and xanthoproteins were detected in BBW, BBH and BBE. Also, significant decreases in TPC, TFC, DPPH activity and FRAP were detected in BBW relative to BBH and BBE. We detected phenolic acids such as gallic acid, caffeic acid, trans-ferulic acid, trans 3-hydroxycinnamic acid and 2-hydroxycinnamic acid, and flavonoids such as quercetin, kaempferol, apigenin and mangiferin in BBE using high-performance liquid chromatography analysis. The strongest antimicrobial activity was observed in Klebsilla pneumonia (MIC50 1.914 µg/mL), followed by E. coli (MIC50 1.923 µg/mL), Shigella (MIC50 1.813 µg/mL) and Salmonella typhi (MIC50 1.617 µg/mL). Bee bread samples possess antioxidant and antimicrobial properties. Bee bread contains phenolic acids and flavonoids, and could be beneficial in the management and treatment of metabolic diseases.
    Matched MeSH terms: Shigella/drug effects; Shigella/pathogenicity
  4. Differential expression of cytokine genes in THP-1-derived macrophages infected with mild and virulence strains of Shigella flexneri 2a
    Shabani NRM, Mokhtar M, Leow CH, Lean QY, Chuah C, Singh KKB, et al.
    Infect Genet Evol, 2020 11;85:104532.
    PMID: 32911076 DOI: 10.1016/j.meegid.2020.104532
    Shigella is an intracellular bacterial pathogen that causes bacterial dysentery called shigellosis. The assessment of pro- and anti-inflammatory mediators produced by immune cells against this bacteria are vital in identifying the effectiveness of the immune reaction in protecting the host. In Malaysia, Shigella is ranked as the third most common bacteria causing diarrheal disease among children below 5 years old. In the present study, we aim to examine the differential cytokine gene expressions of macrophages in response to two types of clinical strains of Shigella flexneri 2a (S. flexneri 2a) isolated from patients admitted in Hospital Universiti Sains Malaysia, Kelantan, Malaysia. THP-1-derived macrophages, as the model of human macrophages, were infected separately with S. flexneri 2a mild (SH062) and virulence (SH057) strains for 6, 12, and 24 h, respectively. The gene expression level of inflammatory mediators was identified using real-time quantitative polymerase chain reaction (RT-qPCR). The production of nitric oxide (NO) by the macrophages was measured by using a commercialized NO assay kit. The ability of macrophages to kill the intracellular bacteria was assessed by intracellular killing assay. Induction of tumor necrosis factor-alpha (TNFα), interleukin (IL)-1β, IL-6, IL-12, inducible NO synthase (iNOS), and NO, confirmed the pro-inflammatory reaction of the THP-1-derived macrophages in response to S. flexneri 2a, especially against the SH507 strain. The SH057 also induced a marked increase in the expression levels of the anti-inflammatory cytokine mRNAs at 12 h and 24 h post-infection. In the intracellular killing assay, both strains showed less viable, indicating the generation of pro-inflammatory cytokines in the presence of iNOS and NO was crucial in the stimulation of macrophages for the host defense against shigellosis. Transcription analysis of THP-1-derived macrophages in this study identifies differentially expressed cytokine genes that correlated with the virulence factor of S. flexneri 2a.
    Matched MeSH terms: Shigella flexneri/genetics*; Shigella flexneri/pathogenicity
  5. Designing and evaluation of an antibody-targeted chimeric recombinant vaccine encoding Shigella flexneri outer membrane antigens
    Kazi A, Hisyam Ismail CMK, Anthony AA, Chuah C, Leow CH, Lim BH, et al.
    Infect Genet Evol, 2020 06;80:104176.
    PMID: 31923724 DOI: 10.1016/j.meegid.2020.104176
    Shigellosis is one of the most common diseases found in the developing countries, especially those countries that are prone flood. The causative agent for this disease is the Shigella species. This organism is one of the third most common enteropathogens responsible for childhood diarrhea. Since Shigella can survive gastric acidity and is an intracellular pathogen, it becomes difficult to treat. Also, uncontrolled use of antibiotics has led to development of resistant strains which poses a threat to public health. Therefore, there is a need for long term control of Shigella infection which can be achieved by designing a proper and effective vaccine. In this study, emphasis was made on designing a candidate that could elicit both B-cell and T-cell immune response. Hence B- and T-cell epitopes of outer membrane channel protein (OM) and putative lipoprotein (PL) from S. flexneri 2a were computationally predicted using immunoinformatics approach and a chimeric construct (chimeric-OP) containing the immunogenic epitopes selected from OM and PL was designed, cloned and expressed in E. coli system. The immunogenicity of the recombinant chimeric-OP was assessed using Shigella antigen infected rabbit antibody. The result showed that the chimeric-OP was a synthetic peptide candidate suitable for the development of vaccine and immunodiagnostics against Shigella infection.
    Matched MeSH terms: Shigella flexneri/genetics; Shigella flexneri/immunology*
  6. Fulltext A small RNA decreases the sensitivity of Shigella sonnei to norfloxacin
    Gan IN, Tan HS
    BMC Res Notes, 2019 Feb 21;12(1):97.
    PMID: 30791948 DOI: 10.1186/s13104-019-4124-4
    OBJECTIVES: Shigella is a human pathogen that causes shigellosis, an acute invasive intestinal infection. Recent studies in the model bacterium Escherichia coli (E. coli) provided evidence that small regulatory RNAs (sRNAs) can contribute to antimicrobial resistance or susceptibility. One of the sRNAs is SdsR, which increases sensitivity of E. coli against fluoroquinolone by repressing the drug efflux pump, TolC. However, no reports exist about the effect of SdsR on fluoroquinolone resistance in Shigella sonnei (S. sonnei). In this study, we established the effect of SdsR on the sensitivity of S. sonnei to norfloxacin.

    DATA DESCRIPTION: We tested the effects of SdsR and SdsRv2 on fluoroquinolone resistance in S. sonnei in vivo. SdsRv2 is a synthetic version which promotes higher binding stability to tolC mRNA. Overexpression of either SdsR or SdsRv2 lowers the expression of tolC mRNA. Interestingly, SdsR and SdsRv2 promote the growth of S. sonnei in the presence of a sub-inhibitory concentration of norfloxacin. Mutant carrying SdsRv2 showed the highest growth advantage. This phenotype is opposite to the effect of SdsR reported in E. coli. This study is an example that demonstrates the difference in the phenotypic effect of a highly conserved sRNA in two closely related bacteria.

    Matched MeSH terms: Shigella sonnei/drug effects*
  7. Fulltext The Antibacterial Activity of Dayak Onion (Eleutherine palmifolia (L.) Merr) towards Pathogenic Bacteria
    Harlita TD, Oedjijono, Asnani A
    Trop Life Sci Res, 2018 Jul;29(2):39-52.
    PMID: 30112140 DOI: 10.21315/tlsr2018.29.2.4
    Antibacterial activity of indigenous Dayak onion (Eleutherine palmifolia (L.) Merr) was investigated. The Dayak onion was solvent extracted with n-hexane, ethyl acetate, and ethanol 96% consecutively. Each extract was tested its antibacterial activity towards methicillin-resistant Staphylococcus aureus (MRSA), Bacillus cereus, Shigella sp., and Pseudomonas aeruginosa using disc diffusion method. The test results showed that the n-hexane, ethyl acetate, and ethanol 96% extracts positively inhibited the growth of MRSA, B. cereus, Shigella sp., and P. aeruginosa. The highest inhibition activity of each extract was obtained with 10 mg/mL of extract concentration; whereas the minimum inhibitory concentration (MIC) of each extract was 2 mg/mL. Extract with the highest inhibition activity was ethyl acetate extract against B. cereus (139.58%). TLC evaluation of ethyl acetate extract showed four spots and bioautography indicated that ethyl acetate extract contained four types of compounds with inhibition activity against B. cereus, in which two compounds have higher antibacterial activity than the other two.
    Matched MeSH terms: Shigella
  8. Fulltext Outer membrane proteins analysis of Shigella sonnei and evaluation of their antigenicity in Shigella infected individuals
    Harikrishnan H, Banga Singh KK, Ismail A
    PLoS One, 2017;12(8):e0182878.
    PMID: 28846684 DOI: 10.1371/journal.pone.0182878
    Bacillary dysentery caused by infection with Shigella spp. remains as serious and common health problem throughout the world. It is a highly multi drug resistant organism and rarely identified from the patient at the early stage of infection. S. sonnei is the most frequently isolated species causing shigellosis in industrialized countries. The antigenicity of outer membrane protein of this pathogen expressed during human infection has not been identified to date. We have studied the antigenic outer membrane proteins expressed by S. sonnei, with the aim of identifying presence of specific IgA and IgG in human serum against the candidate protein biomarkers. Three antigenic OMPs sized 33.3, 43.8 and 100.3 kDa were uniquely recognized by IgA and IgG from patients with S. sonnei infection, and did not cross-react with sera from patients with other types of infection. The antigenic proteome data generated in this study are a first for OMPs of S. sonnei, and they provide important insights of human immune responses. Furthermore, numerous prime candidate proteins were identified which will aid the development of new diagnostic tools for the detection of S. sonnei.
    Matched MeSH terms: Shigella sonnei/immunology*; Shigella sonnei/isolation & purification; Shigella sonnei/metabolism
  9. Fulltext Shigella flexneri serotype 1c derived from serotype 1a by acquisition of gtrIC gene cluster via a bacteriophage
    Tang SS, Carlin NI, Talukder KA, Cam PD, Verma NK
    BMC Microbiol, 2016 Jun 27;16(1):127.
    PMID: 27349637 DOI: 10.1186/s12866-016-0746-z
    BACKGROUND: Shigella spp. are the primary causative agents of bacillary dysentery. Since its emergence in the late 1980s, the S. flexneri serotype 1c remains poorly understood, particularly with regard to its origin and genetic evolution. This article provides a molecular insight into this novel serotype and the gtrIC gene cluster that determines its unique immune recognition.

    RESULTS: A PCR of the gtrIC cluster showed that serotype 1c isolates from different geographical origins were genetically conserved. An analysis of sequences flanking the gtrIC cluster revealed remnants of a prophage genome, in particular integrase and tRNA(Pro) genes. Meanwhile, Southern blot analyses on serotype 1c, 1a and 1b strains indicated that all the tested serotype 1c strains may have had a common origin that has since remained distinct from the closely related 1a and 1b serotypes. The identification of prophage genes upstream of the gtrIC cluster is consistent with the notion of bacteriophage-mediated integration of the gtrIC cluster into a pre-existing serotype.

    CONCLUSIONS: This is the first study to show that serotype 1c isolates from different geographical origins share an identical pattern of genetic arrangement, suggesting that serotype 1c strains may have originated from a single parental strain. Analysis of the sequence around the gtrIC cluster revealed a new site for the integration of the serotype converting phages of S. flexneri. Understanding the origin of new pathogenic serotypes and the molecular basis of serotype conversion in S. flexneri would provide information for developing cross-reactive Shigella vaccines.

    Matched MeSH terms: Shigella flexneri/genetics*; Shigella flexneri/immunology; Shigella flexneri/virology*
  10. Alteration in apyrase enzyme attenuated virulence of Shigella flexneri
    BangaSingh KK, Nisha M, Lau HY, Ravichandran M, Salleh MZ
    Microb Pathog, 2016 Feb;91:123-8.
    PMID: 26706344 DOI: 10.1016/j.micpath.2015.12.004
    Virulence of Shigella is attributed to the genes presence in chromosome or in the megaplasmid. The apy gene which is located in the megaplasmid of Shigella species encodes for apyrase enzyme, a pathogenesis-associated enzyme causing mitochondrial damage and host cell death. In this study we constructed an apy mutant of Shigella flexneri by insertional activation using a kanamycin resistant gene cassette. The wild type apy gene of S. flexneri 2a was PCR amplified, cloned and mutated with insertion of kanamycin resistant gene cassette (aphA). The mutated construct (apy: aphA) was subcloned into a conjugative suicidal vector (pWM91) at the unique Sma1 and Sac1 sites. The mutation of the wild apy gene in the construct was confirmed by DNA sequencing. The mutated construct was introduced into wild type S. flexneri 2a by conjugation with Escherichia coli. After undergoing homologous recombination, the wild apy gene was deleted from the construct using the sucrose selection method. Non-functional activity of the apyrase enzyme in the constructed strain by colorimetric test indicated the successful mutation of the apyrase enzyme. This strain with mutated apy gene was evaluated for its protective efficacy using the guinea pig keratoconjunctivitis model. The strain was Sereny negative and it elicited a significant protection following challenge with wild S. flexneri strain. This apy mutant strain will form a base for the development of a vaccine target for shigellosis.
    Matched MeSH terms: Shigella flexneri/enzymology*; Shigella flexneri/genetics; Shigella flexneri/pathogenicity*
  11. Fulltext Antimicrobial activity and the presence of virulence factors and bacteriocin structural genes in Enterococcus faecium CM33 isolated from ewe colostrum
    Nami Y, Haghshenas B, Haghshenas M, Yari Khosroushahi A
    Front Microbiol, 2015;6:782.
    PMID: 26284059 DOI: 10.3389/fmicb.2015.00782
    Screening of lactic acid bacteria (LAB) isolated from ewe colostrum led to the identification and isolation of Enterococcus faecium CM33 with interesting features like high survival rates under acidic or bile salts condition, high tolerance for the simulated gastrointestinal condition, and high adhesive potential to Caco-2 cells. According the inhibition of pathogen adhesion test results, this strain can reduce more than 50% adhesion capacity of Escherichia coli, Shigella flexneri, Klebsiella pneumoniae, Listeria monocytogenes, and Staphylococcus aureus to Caco-2 cells. Based on the antibiotic sensitivity test findings, E. faecium CM33 was susceptible to gentamycin, vancomycin, erythromycin, ampicillin, penicillin, tetracycline, and rifampicin, but resistant to chloramphenicol, clindamycin, and kanamycin. Upon assessment of the virulence determinants for E. faecium CM33, this strain was negative for all tested virulence genes. Furthermore, the genome of this strain was evaluated for the incidence of the known enterocin genes by specific PCR amplification and discovered the genes encoding enterocins A, 31, X, and Q. Based on this study findings, the strain E. faecium CM33 can be considered as a valuable nutraceutical and can be introduced as a new potential probiotic.
    Matched MeSH terms: Shigella flexneri
  12. Fulltext A real-time loop-mediated isothermal amplification assay for rapid detection of Shigella species
    Liew PS, Teh CS, Lau YL, Thong KL
    Trop Biomed, 2014 Dec;31(4):709-20.
    PMID: 25776596 MyJurnal
    Shigellosis is a foodborne illness caused by the genus Shigella and is an important global health issue. The development of effective techniques for rapid detection of this pathogen is essential for breaking the chain of transmission. Therefore, we have developed a novel loop-mediated isothermal amplification (LAMP) assay targeting the invasion plasmid antigen H (ipaH) gene to rapidly detect Shigella species. This assay could be performed in 90 min at an optimal temperature of 64ºC, with endpoint results visualized directly. Notably, the method was found to be more sensitive than conventional PCR. Indeed, the detection limit for the LAMP assay on pure bacterial cultures was 5.9 x 10(5) CFU/ml, while PCR displayed a limit of 5.9 x 10(7) CFU/ml. In spiked lettuce samples, the sensitivity of the LAMP assay was 3.6 x 10(4) CFU/g, whereas PCR was 3.6 x 10(5) CFU/g. Overall, the assay accurately identified 32 Shigella spp. with one enteroinvasive Escherichia coli displaying positive reaction while the remaining 32 non-Shigella strains tested were negative.
    Matched MeSH terms: Shigella/genetics; Shigella/isolation & purification*
  13. Fulltext A pentaplex PCR assay for the detection and differentiation of Shigella species
    Ojha SC, Yean Yean C, Ismail A, Singh KK
    Biomed Res Int, 2013;2013:412370.
    PMID: 23509722 DOI: 10.1155/2013/412370
    The magnitude of shigellosis in developing countries is largely unknown because an affordable detection method is not available. Current laboratory diagnosis of Shigella spp. is laborious and time consuming and has low sensitivity. Hence, in the present study, a molecular-based diagnostic assay which amplifies simultaneously four specific genes to identify invC for Shigella genus, rfc for S. flexneri, wbgZ for S. sonnei, and rfpB for S. dysenteriae, as well as one internal control (ompA) gene, was developed in a single reaction to detect and differentiate Shigella spp. Validation with 120 Shigella strains and 37 non-Shigella strains yielded 100% specificity. The sensitivity of the PCR was 100 pg of genomic DNA, 5.4 × 10(4) CFU/ml, or approximately 120 CFU per reaction mixture of bacteria. The sensitivity of the pentaplex PCR assay was further improved following preincubation of the stool samples in gram-negative broth. A preliminary study with 30 diarrhoeal specimens resulted in no cross-reaction with other non-Shigella strains tested. We conclude that the developed pentaplex PCR assay is robust and can provide information about the four target genes that are essential for the identification of the Shigella genus and the three Shigella species responsible for the majority of shigellosis cases.
    Matched MeSH terms: Shigella/isolation & purification*
  14. Fulltext Temperature-regulated expression of outer membrane proteins in Shigella flexneri
    Harikrishnan H, Ismail A, Banga Singh KK
    Gut Pathog, 2013;5(1):38.
    PMID: 24330657 DOI: 10.1186/1757-4749-5-38
    Bacteria exist widely in a diversity of natural environments. In order to survive adverse conditions such as nutrient depletion, biochemical and biological disturbances, and high temperature, bacteria have developed a wide variety of coping mechanisms. Temperature is one of the most important factors that can enhance the expression of microbial proteins. This study was conducted to investigate how outer membrane proteins (OMPs) of the bacterium Shigella flexneri respond to stress, especially during fever when the host's body temperature is elevated.
    Matched MeSH terms: Shigella flexneri
  15. Fulltext Detection of enterotoxin targeted entFM and hblA genes by inoculating Bacillus cereus (Strain BC1) into ready-to-eat food (RTF) and drink samples using polymerase chain reaction (PCR)
    Nooratiny, I., Sahilah, A.M.
    International Food Research Journal, 2013;20(4):1895-1899.
    MyJurnal
    Detection of enterotoxin by targeting entFM and hblA genes in Bacillus cereus BC1 strain inoculated into ready to eat food (RTF) and drink samples using polymerase chain reaction (PCR) was conducted. The B. cereus BC1 strain was confirmed as a Bacillus diarrhoeal enterotoxin (BDE) when tested by a commercially available Enzyme-linked immunosorbent assay-BDE immunoassay (ELISA-BDE immunoassay, TECRA). In the specificity study, both enterotoxin genes were detected on chromosomal DNA of B. cereus BC1 strain by showing a specific band of 1269 bp (entFM) and 874 bp (hblA), respectively. However, none of the target genes were detected for the other 15 genomic DNA bacteria (B. cereus (ATCC 11779), B. subtilis (ATCC 6633), Campylobacter jejuni (ATCC 29428), C. coli (Jabatan Kimia Malaysia, JKM), Clostridium perfringen (ATCC 13124), Enterobacter sakazaki (ATCC 51329), Escherichia coli (ATCC 43888), E. coli (ATCC 11735), Legionella pneumophila (ATCC 33152), Listeria monocytogenes (ATCC 35967), Salmonella typhi (IMR), S. enteritidis (ATCC 13076), S. typhimurium (ATCC 14028), Shigella flexeneri (ATCC 12022) and Vibrio cholerae bengal (Institute Medical Research (IMR), Malaysia) examined. The detection limit of both genes was 0.1 ng of genomic DNA. Thus, in the presence study it is evidence that the PCR analysis targeting enterotoxin of entFM and hblA genes are suitable and useful in detecting enterotoxic B. cereus in RTFs and drinks contaminated sample.
    Matched MeSH terms: Shigella
  16. Pengesahan bagi mengesan bakteria patogen makanan menggunakan teknologi mikroaturan DNA
    SAWEI J, NORRAKIAH ABDULLAH SANI, AMINAH ABDULLAH, SAHILAH ABD. MUTALIB
    Sains Malaysiana, 2013;42:1715-1720.
    Kajian ini dijalankan untuk mengesahkan kemampuan teknologi DNA mikroaturan cip gen OliproTM FoodPATH bagi mengesan bakteria patogen makanan. Sebanyak 9 jenis DNA bakteria patogen makanan telah digunakan iaitu Bacillus cereus, Escherichia coli O157:H7, Staphylococcus aureus, Vibrio cholerae, Vibrio parahaemolyticus, Listeria monocytogenes, Salmonella spp., Shigella spp. dan Campylobacter spp. Sebanyak 36 kombinasi templat DNA bakteria patogen makanan telah digunakan. Pengesahan bagi mengesan bakteria patogen makanan dilakukan dengan menggunakan kaedah reaksi berantai polimerase (PCR) dan penghibridan Southern-blotting di atas cip gen untuk mengesahkan kemampuannya. Keputusan daripada analisis hibridasi di atas cip gen telah dibandingkan dengan hasil gel elektroforesis 2.0% (w/v). Lima saringan diperlukan untuk menghabiskan 36 kombinasi templat DNA bakteria patogen makanan. Setiap saringan, satu cip gen telah digunakan sebagai kawalan negatif tidak diinokulasikan dengan sebarang kombinasi DNA bakteria patogen makanan. Daripada hasil kajian, didapati bahawa semua kombinasi templat DNA bakteria patogen makanan telah dapat dikesan. Cip yang digunakan sebagai kawalan negatif tidak menunjukkan kehadiran DNA. Oleh itu, daripada kajian ini cip gen OliproTM FoodPATH didapati memberikan keputusan yang lebih baik berbanding dengan 2.0% (w/v) gel elektroforesis.
    Matched MeSH terms: Shigella
  17. Fulltext Characterization of Shigella sonnei in Malaysia, an increasingly prevalent etiologic agent of local shigellosis cases
    Koh XP, Chiou CS, Ajam N, Watanabe H, Ahmad N, Thong KL
    BMC Infect Dis, 2012;12:122.
    PMID: 22606962 DOI: 10.1186/1471-2334-12-122
    Shigellosis is a major public health concern worldwide, especially in developing countries. It is an acute intestinal infection caused by bacteria of the genus Shigella, with a minimum infective dose as low as 10-100 bacterial cells. Increasing prevalence of Shigella sonnei as the etiologic agent of shigellosis in Malaysia has been reported. As there is limited information on the genetic background of S. sonnei in Malaysia, this study aimed to characterize Malaysian S. sonnei and to evaluate the prospect of using multilocus variable-number tandem-repeat (VNTR) analysis (MLVA) for subtyping of local S. sonnei.
    Matched MeSH terms: Shigella sonnei/classification*; Shigella sonnei/genetics; Shigella sonnei/isolation & purification*
  18. A 35 kDa antigenic protein from Shigella flexneri: in silico structural and functional studies
    Yung-Hung RL, Ismail A, Lim TS, Choong YS
    Biochem Biophys Res Commun, 2011 Nov 18;415(2):229-34.
    PMID: 21982766 DOI: 10.1016/j.bbrc.2011.09.116
    Shigella flexneri serotype 2a is a major public health concern in the developing and under-developed countries which contributes to shigellosis endemic and mortality. Thus, there is an urgent need for a rapid diagnostic test for effective therapy and disease management. Previous study showed that a ∼35 kDa antigenic protein from S. flexneri is a potential biomarker. We therefore modelled the three-dimensional structure of the antigen to probe its functionality which could aid in the development of an antigen-based diagnostic. Results showed that the antigen is a transmembrane protein consists of OmpA and OmpA-like domains. The OmpA domain is a beta-barrel embedded in the outer membrane with four surface-exposed extracellular loops. The OmpA-like domain is linked to the OmpA domain with a 17 amino acids linker and located in the periplasmic. Docking of peptidoglycan into the groove of OmpA-like domain might help in catalyzing the bacterial cell wall formation. Both domains are expected to be involved in the virulence, structural stability, pathogenesis and survival of Shigella thus made the 35 kDa protein a suitable shigellosis diagnostic biomarker. This structural elucidation will also enable a better identification of the epitope regions for the development of specific binders to the 35 kDa antigen.
    Matched MeSH terms: Shigella flexneri/immunology*
  19. A 9-year study of shigellosis in Northeast Malaysia: Antimicrobial susceptibility and shifting species dominance
    Banga Singh KK, Ojha SC, Deris ZZ, Rahman RA
    Z Gesundh Wiss, 2011 Jun;19(3):231-236.
    PMID: 21654922
    AIMS: In Malaysia, Shigella spp. is the third most common bacterial agent responsible for childhood diarrhoea. This study was conducted to determine the prevalence and antimicrobial susceptibility patterns of Shigella spp. isolated from patients admitted to the Hospital Universiti Sains Malaysia from January 2001 to December 2009. SUBJECTS AND METHODS: A hospital-based retrospective study was used. Stool samples from patients were cultured using a standard culture method. Shigella spp. isolates were identified by biochemical and serological methods, and the antimicrobial susceptibility pattern was evaluated using the Kirby-Bauer disc-diffusion method. RESULTS: A total of 138 Shigella spp. were isolated from a total of 14,830 routine stool specimens, yielding an isolation rate of 0.93% that corresponded to 9.99% of the 1,381 bacterial pathogens isolated. Of these isolates, S. sonnei was the predominant species, followed by S. flexneri and S. boydii. Seasonal variation was noticed, and no significant differences were detected in the demographic data for S. flexneri and S. sonnei. The susceptibility of all isolated Shigella strains was tested against seven antibiotics. Ceftriaxone (99.1%), ciprofloxacin (98.4%), and nalidixic acid (93.8%) were effective against the Shigella strains, whereas tetracycline and trimethoprim-sulfamethoxazole exhibited high frequencies of resistance (58.4% and 53.8%, respectively). CONCLUSION: This study is important for public health education aimed at reducing the morbidity and mortality associated with Shigella spp. infection. Our results also will be helpful for paediatricians and microbiologists in the selection of appropriate antibiotics for the management of diarrhoea.
    Matched MeSH terms: Shigella
  20. Fulltext Fabrication of silver nanoparticles doped in the zeolite framework and antibacterial activity
    Shameli K, Ahmad MB, Zargar M, Yunus WM, Ibrahim NA
    Int J Nanomedicine, 2011;6:331-41.
    PMID: 21383858 DOI: 10.2147/IJN.S16964
    Using the chemical reduction method, silver nanoparticles (Ag NPs) were effectively synthesized into the zeolite framework in the absence of any heat treatment. Zeolite, silver nitrate, and sodium borohydride were used as an inorganic solid support, a silver precursor, and a chemical reduction agent, respectively. Silver ions were introduced into the porous zeolite lattice by an ion-exchange path. After the reduction process, Ag NPs formed in the zeolite framework, with a mean diameter of about 2.12-3.11 nm. The most favorable experimental condition for the synthesis of Ag/zeolite nanocomposites (NCs) is described in terms of the initial concentration of AgNO(3). The Ag/zeolite NCs were characterized by ultraviolet-visible spectroscopy, powder X-ray diffraction, transmission electron microscopy, scanning electron microscopy, energy dispersive X-ray fluorescence, and Fourier transform infrared. The results show that Ag NPs form a spherical shape with uniform homogeneity in the particle size. The antibacterial activity of Ag NPs in zeolites was investigated against Gram-negative bacteria (ie, Escherichia coli and Shigella dysentriae) and Gram-positive bacteria (ie, Staphylococcus aureus and methicillin-resistant Staphylococcus aureus) by disk diffusion method using Mueller-Hinton agar at different sizes of Ag NPs. All of the synthesized Ag/zeolite NCs were found to have antibacterial activity. These results show that Ag NPs in the zeolite framework can be useful in different biological research and biomedical applications.
    Matched MeSH terms: Shigella dysenteriae/drug effects
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