Displaying publications 21 - 40 of 130 in total

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  1. Trends in the antibiotic resistance patterns of enteric Fever isolates - a three year report from a tertiary care centre
    Gupta V, Singla N, Bansal N, Kaistha N, Chander J
    Malays J Med Sci, 2013 Jul;20(4):71-5.
    PMID: 24043999
    BACKGROUND: The incidence of multidrug resistant enteric fever is increasing alarmingly. This study was planned to determine the rate of isolation of Salmonella spp. and to compare the isolates for their epidemiological parameters and antimicrobial susceptibility patterns at our center.

    METHODS: The study was conducted over a span of three years with a total of 8142, 8134, and 8114 blood culture samples processed for the years 2008, 2009, and 2010 respectively. The minimum inhibitory concentration (MIC) for ciprofloxacin and chloramphenicol was determined using an agar dilution method. The MIC for ciprofloxacin was also confirmed by Epsilon-test (E -test) strips.

    RESULTS: Of the total 302 Salmonella spp. isolated, 257 were Salmonella enterica serotype Typhi (85.1%) and 45 (14.9%) were S. enterica serotype Paratyphi A. The majority of the isolates recovered were from the pediatric age group (54.6%) and males (60.6%). Complete susceptibility was observed to chloramphenicol, cefotaxime, ceftriaxone, and azithromycin over the last two years (2009 and 2010), with an increase in resistance to nalidixic acid (100%) and ciprofloxacin (13.6%).

    CONCLUSION: In our study, we found augmentation of resistance to nalidixic acid and fluoroquinolones and complete sensitivity to ceftriaxone along with reemergence of chloramphenicol sensitivity for Salmonella isolates. This report emphasises the necessity of continuous surveillance of antibiograms of enteric fever isolates in an area.

    Matched MeSH terms: Salmonella typhi
  2. Fulltext New advances in the diagnosis of typhoid and detection of typhoid carriers
    Ismail A
    Malays J Med Sci, 2000 Jul;7(2):3-8.
    PMID: 22977383 MyJurnal
    For effective management of typhoid, diagnosis of the disease must be done with speed and accuracy. Development of such a test would require antigens that are specific for typhoid diagnosis. Attempts at finding the specific antigen have been carried out throughout the years. The finding of such an antigen can lead to carrier detection as well. Candidate antigens have been used in the development of antigen or antibody detection tests with variation in sensitivity and specificity. Further characterization and understanding of the candidate antigens combined with use of innovative technologies will allow for the ideal test for typhoid and typhoid carriers to be within reach.
    Matched MeSH terms: Salmonella typhi
  3. Fulltext Typhoid and malaria co-infection - an interesting finding in the investigation of a tropical Fever
    Sulaiman W
    Malays J Med Sci, 2006 Jul;13(2):64-5.
    PMID: 22589607 MyJurnal
    Malaysia is endemic for both these diseases and one should not be too surprised when faced with a diagnosis of co-infection of typhoid and malaria, as have been described in India and Canada. Here we describe one such case of Salmonella typhi and Plasmodium vivax infection.
    Matched MeSH terms: Salmonella typhi
  4. Extensively drug-resistant typhoid fever in Pakistan
    Rasheed MK, Hasan SS, Babar ZU, Ahmed SI
    Lancet Infect Dis, 2019 03;19(3):242-243.
    PMID: 30833059 DOI: 10.1016/S1473-3099(19)30051-9
    Matched MeSH terms: Salmonella typhi
  5. Salmonella serotypes isolated from man in Malaysia over the 10-year period 1973-1982
    Jegathesan M
    J Hyg (Lond), 1984 Jun;92(3):395-9.
    PMID: 6376627
    The results of serotyping of 10 953 salmonella isolates from humans over a 10-year period, 1973-82 at the Bacteriology Division, Institute for Medical Research, Malaysia are presented. A total of 104 serotypes from 22 'O' groups were encountered; 95 isolates were considered untypable. The three most predominant serotypes, namely Salmonella typhi, S. typhimurium and S. weltevreden together accounted for 54.1% of all isolates whilst the 25 most frequent serotypes accounted for 93.6% of the total. Whilst the commoner serotypes occurred regularly throughout the study period, the rarer ones tended to appear only in one year, when they might be associated with an outbreak, and never again. The pattern of serotypes, though quite similar to the one seen in neighbouring Singapore, is different from those experienced in other places such as Hong Kong, Jakarta, Bangladesh and Manchester.
    Matched MeSH terms: Salmonella typhi/classification; Salmonella typhi/isolation & purification; Salmonella typhimurium/classification; Salmonella typhimurium/isolation & purification
  6. Phage types of Salmonella typhi isolated in Malaysia over the 10-year period 1970-1979
    Jegathesan M
    J Hyg (Lond), 1983 Feb;90(1):91-7.
    PMID: 6822730
    The pattern of phage types of 2553 strains of Salmonella typhi isolated over the 10-year period 1970-9 was studied. During the period 29 different phage types were encountered, not including the categories of 'untypable strains', 'degraded Vi-strains' and Vi negative strains. For the period as a whole, the commonest phage types encountered were A (20.9%), E1 (14.8%), D1 (10.3%), degraded Vi positive strains (10.3%), untypable Vi strains (7.3%), C4 (7.1%), D2 (4.4%), E2 (3.9%) and type 25 (2.6%). There were phage types which appeared in the early years of the period and then disappeared (types B2, D9 and D1-N). Others only made their appearance in recent years (K1 and 53). Notable differences were also seen in the predilection of some phage types for certain geographical areas.
    Matched MeSH terms: Salmonella typhi/classification*; Salmonella typhi/isolation & purification
  7. Salmonella enterica serovar Typhi cutF is upregulated during environmental stress
    Lau KL, Ong EB, Zainudin ZF, Samian MR, Ismail A, Najimudin N
    J Gen Appl Microbiol, 2013;59(3):239-44.
    PMID: 23863294
    Matched MeSH terms: Salmonella typhi/genetics; Salmonella typhi/growth & development; Salmonella typhi/metabolism; Salmonella typhi/physiology*
  8. Rapid serologic diagnosis of pediatric typhoid fever in an endemic area: a prospective comparative evaluation of two dot-enzyme immunoassays and the Widal test
    Bhutta ZA, Mansurali N
    Am J Trop Med Hyg, 1999 Oct;61(4):654-7.
    PMID: 10548305
    We evaluated the diagnostic sensitivity and specificity of two dot-enzyme-linked immunoassays (Typhidot and Typhidot-M; Malaysian Biodiagnostic Research SDN BHD, Kuala Lumpur, Malaysia), assessing IgG and IgM antibodies against the outer membrane protein (OMP) of Salmonella typhi, and the Widal test in comparison with blood culture in a consecutive group of children with suspected typhoid fever. Of 97 children with suspected typhoid fever, the disease was confirmed bacteriologically in 46 (47%), whereas 25 (26%) were considered to have typhoid fever on clinical grounds. An alternative diagnosis was made in 26 (27%). The Typhidot and Typhidot-M were superior to the Widal test in their diagnostic sensitivity and specificity, although values (sensitivity = 85-94% and specificity = 77-89%) were significantly lower than in other regional reports. The lower specificity of the Typhidot in our series may represent regional differences in the genomic structure and plasticity of the OMP of S. typhi and merits further evaluation of these tests in diverse geographic locations.
    Matched MeSH terms: Salmonella typhi/immunology; Salmonella typhi/isolation & purification*
  9. Longevity of antibody responses to a Salmonella typhi-specific outer membrane protein: interpretation of a dot enzyme immunosorbent assay in an area of high typhoid fever endemicity
    Choo KE, Davis TM, Ismail A, Ong KH
    Am J Trop Med Hyg, 1997 Dec;57(6):656-9.
    PMID: 9430522
    The objective of this study was to investigate the longevity of positive dot enzyme immunosorbent assay (dot EIA) results for IgM and IgG to a Salmonella typhi outer membrane protein in Malaysian children with enteric fever. The patients were children one month to 12 years of age with clinical evidence of typhoid fever, positive blood or stool cultures for S. typhi, and/or a positive Widal test result who were admitted over a two-year period to General Hospital (Kota Bharu, Malaysia). These patients received standard inpatient treatment for enteric fever including chloramphenicol therapy for 14 days. Dot EIA tests were performed as part of clinical and laboratory assessments on admission, at two weeks, and then at 3, 6, 9, 12, 15, 18, and 21 months postdischarge. Assessment of the longevity of positive dot EIA IgM and IgG titers was done by Kaplan-Meier analysis. In 94 evaluable patients, 28% were dot EIA IgM positive but IgG negative on admission, 50% were both IgM and IgG positive, and 22% were IgM negative and IgG positive. Mean persistence of IgM dot EIA positivity was 2.6 months (95% confidence interval = 2.0-3.1 months) and that of IgG was 5.4 months (4.5-6.3 months). There were no significant differences between the three subgroups. Thus, positive IgM and IgG results determined by dot EIA within four and seven months, respectively, following documented or suspected enteric fever in a child from an endemic area should be interpreted with caution. In other clinical situations, the dot EIA remains a rapid and reliable aid to diagnosis.
    Matched MeSH terms: Salmonella typhi/immunology*
  10. Fulltext Typhoid fever in children--a retrospective study of 54 cases from Malaysia
    Yap YF, Puthucheary SD
    Singapore Med J, 1998 Jun;39(6):260-2.
    PMID: 9803814
    Typhoid fever, which is endemic in Malaysia, affects all age groups and it has been stated that classical features described in textbooks were absent in children. The aim of this study was to find out whether this was true in the local setting and hence a retrospective study was undertaken.
    Matched MeSH terms: Salmonella typhi/isolation & purification*
  11. Fulltext Crystal structure of an antigenic outer-membrane protein from Salmonella Typhi suggests a potential antigenic loop and an efflux mechanism
    Guan HH, Yoshimura M, Chuankhayan P, Lin CC, Chen NC, Yang MC, et al.
    Sci Rep, 2015 Nov 13;5:16441.
    PMID: 26563565 DOI: 10.1038/srep16441
    ST50, an outer-membrane component of the multi-drug efflux system from Salmonella enterica serovar Typhi, is an obligatory diagnostic antigen for typhoid fever. ST50 is an excellent and unique diagnostic antigen with 95% specificity and 90% sensitivity and is used in the commercial diagnosis test kit (TYPHIDOT(TM)). The crystal structure of ST50 at a resolution of 2.98 Å reveals a trimer that forms an α-helical tunnel and a β-barrel transmembrane channel traversing the periplasmic space and outer membrane. Structural investigations suggest significant conformational variations in the extracellular loop regions, especially extracellular loop 2. This is the location of the most plausible antibody-binding domain that could be used to target the design of new antigenic epitopes for the development of better diagnostics or drugs for the treatment of typhoid fever. A molecule of the detergent n-octyl-β-D-glucoside is observed in the D-cage, which comprises three sets of Asp361 and Asp371 residues at the periplasmic entrance. These structural insights suggest a possible substrate transport mechanism in which the substrate first binds at the periplasmic entrance of ST50 and subsequently, via iris-like structural movements to open the periplasmic end, penetrates the periplasmic domain for efflux pumping of molecules, including poisonous metabolites or xenobiotics, for excretion outside the pathogen.
    Matched MeSH terms: Salmonella typhi/genetics; Salmonella typhi/metabolism; Salmonella typhi/physiology*
  12. Fulltext Delineation of B-cell Epitopes of Salmonella enterica serovar Typhi Hemolysin E: Potential antibody therapeutic target
    Chin CF, Lai JY, Choong YS, Anthony AA, Ismail A, Lim TS
    Sci Rep, 2017 05 19;7(1):2176.
    PMID: 28526816 DOI: 10.1038/s41598-017-01987-8
    Hemolysin E (HlyE) is an immunogenic novel pore-forming toxin involved in the pathogenesis of typhoid fever. Thus, mapping of B-cell epitopes of Salmonella enterica serovar Typhi (S. Typhi) is critical to identify key immunogenic regions of HlyE. A random 20-mer peptide library was used for biopanning with enriched anti-HlyE polyclonal antibodies from typhoid patient sera. Bioinformatic tools were used to refine, analyze and map the enriched peptide sequences against the protein to identify the epitopes. The analysis identified both linear and conformational epitopes on the HlyE protein. The predicted linear GAAAGIVAG and conformational epitope PYSQESVLSADSQNQK were further validated against the pooled sera. The identified epitopes were then used to isolate epitope specific monoclonal antibodies by antibody phage display. Monoclonal scFv antibodies were enriched for both linear and conformational epitopes. Molecular docking was performed to elucidate the antigen-antibody interaction of the monoclonal antibodies against the epitopes on the HlyE monomer and oligomer structure. An in-depth view of the mechanistic and positional characteristics of the antibodies and epitope for HlyE was successfully accomplished by a combination of phage display and bioinformatic analysis. The predicted function and structure of the antibodies highlights the possibility of utilizing the antibodies as neutralizing agents for typhoid fever.
    Matched MeSH terms: Salmonella typhi/genetics; Salmonella typhi/immunology*
  13. Fulltext Evaluation of in-vitro antioxidant and antibacterial properties of Commelina nudiflora L. extracts prepared by different polar solvents
    Kuppusamy P, Yusoff MM, Parine NR, Govindan N
    Saudi J Biol Sci, 2015 May;22(3):293-301.
    PMID: 25972750 DOI: 10.1016/j.sjbs.2014.09.016
    The study explored on the commonly available weed plant Commelina nudiflora which has potential in-vitro antioxidant and antimicrobial activity. The different polar solvents such as ethanol, chloroform, dichloromethane, hexane and aqueous were used for the soxhlet extraction. The extracts were identified pharmacologically as important bioactive compounds and their potential free radical scavenging activities, and antimicrobial properties were studied. C. nudiflora extracts were monitored on their in-vitro antioxidant ability by DPPH and ABTS radical scavenging assay. Aqueous extract shows significant free radical scavenging activity of 63.4 mg/GAE and 49.10 mg/g in DPPH and ABTS respectively. Furthermore, the aqueous crude extract was used in antibacterial studies, which shows the highest inhibitory activity against Pseudomonas aeruginosa, Escherichia coli and Salmonella typhi. Among all the extracts, aqueous extract of C. nudiflora has significant control over free radical scavenging activity and inhibition of the growth of food pathogenic bacteria. Also, the aqueous extract contains abundance of phenolics and flavonoids higher than other extracts. This study explored weed plant C. nudiflora as a potential source of antioxidant and antibacterial efficacy and identified various therapeutic value bioactive compounds from GC-MS analysis.
    Matched MeSH terms: Salmonella typhi
  14. Synthesis of cephradine metal complexes and its anti-bacterial evaluation
    Iqbal Hussain, Syed Salman, Sarwat Iftikhar, Samin Jan, Junaid Akhter, Muhammad Ramzan, et al.
    Sains Malaysiana, 2018;47:749-754.
    Cephradine belongs to the first generation cephalosporin having a broad range of anti-bacterial activities. In the
    present work, Cephradine wasreacted with different metal salts. These metal salts were Iron, Copper, Cobalt and Nickel
    salts. All the complexes of Cephradine metals were synthesized at room temperature using a mechanical vibrator.
    The reactions yielded the coordinated complexes within 5-10 min with improved product yield. The synthesized
    complexes were analyzed for their antibacterial power using disc diffused assay. All the Cephradine complexes showed
    powerful antibacterial activity. The Co, Cu, Ni and Sn complexes showed good antibacterial activities 18.5 mm by Cu
    complexes against S. typhi, 17 mm against B. subtillus 16.5 mm against S. aureus, 16 mm against S. coccus. Similarly
    Sn complexes exhibited 17 mm zone of inhibition against S. coccus and 15.5 mm against B. subtillus. Cobalt and Ni
    complexes also shed significant inhibition activities against bacterial pathogenic bacterial strains. The study is of
    particular importance and new, using mechanical vibrator for the first time. The product yield is also comparatively
    good with short reaction time.
    Matched MeSH terms: Salmonella typhi
  15. Genome size variation among recent human isolates of Salmonella typhi
    Thong KL, Puthucheary SD, Pang T
    Res. Microbiol., 1997 Mar-Apr;148(3):229-35.
    PMID: 9765803
    We performed genome size estimation of 17 recent human isolates of Salmonella typhi from geographically diverse regions using pulsed-field gel electrophoresis (PFGE) after digestion of chromosomal DNA with restriction endonucleases XbaI (5'-TCTAGA-3'), AvrII (5'-CCTAGG-3') and SpeI (5'-ACTAGT-3'), and summation of the sizes of restriction fragments obtained. All 17 isolates had circular chromosomes, and genome sizes differed by as much as 959 kb, ranging from 3,964 to 4,923 kb (mean genome size = 4,528 kb). The data obtained confirm the usefulness of PFGE in studies of bacterial genome size and are in agreement with recent results indicating considerable genetic diversity and genomic plasticity of S. typhi. The variation in genome sizes noted may be relevant to the observed biological properties of this important human pathogen, including its virulence.
    Matched MeSH terms: Salmonella typhi/genetics*; Salmonella typhi/isolation & purification
  16. Fulltext War against COVID-19: looming threat of XDR typhoid battle in Pakistan
    Tanveer M, Ahmed A, Siddiqui A, Rehman IU, Hashmi FK
    Public Health, 2021 09;198:e15-e16.
    PMID: 34187703 DOI: 10.1016/j.puhe.2021.05.019
    Matched MeSH terms: Salmonella typhi
  17. Fulltext Variable carbon catabolism among Salmonella enterica serovar Typhi isolates
    Chai LC, Kong BH, Elemfareji OI, Thong KL
    PLoS One, 2012;7(5):e36201.
    PMID: 22662115 DOI: 10.1371/journal.pone.0036201
    Salmonella enterica serovar Typhi (S. Typhi) is strictly a human intracellular pathogen. It causes acute systemic (typhoid fever) and chronic infections that result in long-term asymptomatic human carriage. S. Typhi displays diverse disease manifestations in human infection and exhibits high clonality. The principal factors underlying the unique lifestyle of S. Typhi in its human host during acute and chronic infections remain largely unknown and are therefore the main objective of this study.
    Matched MeSH terms: Salmonella typhi/isolation & purification; Salmonella typhi/metabolism*
  18. Fulltext Variable Responses to Carbon Utilization between Planktonic and Biofilm Cells of a Human Carrier Strain of Salmonella enterica Serovar Typhi
    Kalai Chelvam K, Yap KP, Chai LC, Thong KL
    PLoS One, 2015;10(5):e0126207.
    PMID: 25946205 DOI: 10.1371/journal.pone.0126207
    Salmonella enterica serovar Typhi (S. Typhi) is a foodborne pathogen that causes typhoid fever and infects only humans. The ability of S. Typhi to survive outside the human host remains unclear, particularly in human carrier strains. In this study, we have investigated the catabolic activity of a human carrier S. Typhi strain in both planktonic and biofilm cells using the high-throughput Biolog Phenotype MicroArray, Minimum Biofilm Eradication Concentration (MBEC) biofilm inoculator (96-well peg lid) and whole genome sequence data. Additional strains of S. Typhi were tested to further validate the variation of catabolism in selected carbon substrates in the different bacterial growth phases. The analyzes of the carbon utilization data indicated that planktonic cells of the carrier strain, S. Typhi CR0044 could utilize a broader range of carbon substrates compared to biofilm cells. Pyruvic acid and succinic acid which are related to energy metabolism were actively catabolised in the planktonic stage compared to biofilm stage. On the other hand, glycerol, L-fucose, L-rhamnose (carbohydrates) and D-threonine (amino acid) were more actively catabolised by biofilm cells compared to planktonic cells. Notably, dextrin and pectin could induce strong biofilm formation in the human carrier strain of S. Typhi. However, pectin could not induce formation of biofilm in the other S. Typhi strains. Phenome data showed the utilization of certain carbon substrates which was supported by the presence of the catabolism-associated genes in S. Typhi CR0044. In conclusion, the findings showed the differential carbon utilization between planktonic and biofilm cells of a S. Typhi human carrier strain. The differences found in the carbon utilization profiles suggested that S. Typhi uses substrates mainly found in the human biliary mucus glycoprotein, gallbladder, liver and cortex of the kidney of the human host. The observed diversity in the carbon catabolism profiles among different S. Typhi strains has suggested the possible involvement of various metabolic pathways that might be related to the virulence and pathogenesis of this host-restricted human pathogen. The data serve as a caveat for future in-vivo studies to investigate the carbon metabolic activity to the pathogenesis of S. Typhi.
    Matched MeSH terms: Salmonella typhi/genetics; Salmonella typhi/pathogenicity*; Salmonella typhi/physiology*
  19. Fulltext Non-protein coding RNA genes as the novel diagnostic markers for the discrimination of Salmonella species using PCR
    Nithya R, Ahmed SA, Hoe CH, Gopinath SC, Citartan M, Chinni SV, et al.
    PLoS One, 2015;10(3):e0118668.
    PMID: 25774907 DOI: 10.1371/journal.pone.0118668
    Salmonellosis, a communicable disease caused by members of the Salmonella species, transmitted to humans through contaminated food or water. It is of paramount importance, to generate accurate detection methods for discriminating the various Salmonella species that cause severe infection in humans, including S. Typhi and S. Paratyphi A. Here, we formulated a strategy of detection and differentiation of salmonellosis by a multiplex polymerase chain reaction assay using S. Typhi non-protein coding RNA (sRNA) genes. With the designed sequences that specifically detect sRNA genes from S. Typhi and S. Paratyphi A, a detection limit of up to 10 pg was achieved. Moreover, in a stool-seeding experiment with S. Typhi and S. Paratyphi A, we have attained a respective detection limit of 15 and 1.5 CFU/mL. The designed strategy using sRNA genes shown here is comparatively sensitive and specific, suitable for clinical diagnosis and disease surveillance, and sRNAs represent an excellent molecular target for infectious disease.
    Matched MeSH terms: Salmonella typhi/genetics; Salmonella typhi/isolation & purification; Salmonella typhi/chemistry
  20. Fulltext Prodigiosin inhibits bacterial growth and virulence factors as a potential physiological response to interspecies competition
    Yip CH, Mahalingam S, Wan KL, Nathan S
    PLoS One, 2021;16(6):e0253445.
    PMID: 34161391 DOI: 10.1371/journal.pone.0253445
    Prodigiosin, a red linear tripyrrole pigment, has long been recognised for its antimicrobial property. However, the physiological contribution of prodigiosin to the survival of its producing hosts still remains undefined. Hence, the aim of this study was to investigate the biological role of prodigiosin from Serratia marcescens, particularly in microbial competition through its antimicrobial activity, towards the growth and secreted virulence factors of four clinical pathogenic bacteria (methicillin-resistant Staphylococcus aureus (MRSA), Enterococcus faecalis, Salmonella enterica serovar Typhimurium and Pseudomonas aeruginosa) as well as Staphylococcus aureus and Escherichia coli. Prodigiosin was first extracted from S. marcescens and its purity confirmed by absorption spectrum, high performance liquid chromatography (HPLC) and liquid chromatography-tandem mass spectrophotometry (LC-MS/MS). The extracted prodigiosin was antagonistic towards all the tested bacteria. A disc-diffusion assay showed that prodigiosin is more selective towards Gram-positive bacteria and inhibited the growth of MRSA, S. aureus and E. faecalis and Gram-negative E. coli. A minimum inhibitory concentration of 10 μg/μL of prodigiosin was required to inhibit the growth of S. aureus, E. coli and E. faecalis whereas > 10 μg/μL was required to inhibit MRSA growth. We further assessed the effect of prodigiosin towards bacterial virulence factors such as haemolysin and production of protease as well as on biofilm formation. Prodigiosin did not inhibit haemolysis activity of clinically associated bacteria but was able to reduce protease activity for MRSA, E. coli and E. faecalis as well as decrease E. faecalis, Salmonella Typhimurium and E. coli biofilm formation. Results of this study show that in addition to its role in inhibiting bacterial growth, prodigiosin also inhibits the bacterial virulence factor protease production and biofilm formation, two strategies employed by bacteria in response to microbial competition. As clinical pathogens were more resistant to prodigiosin, we propose that prodigiosin is physiologically important for S. marcescens to compete against other bacteria in its natural soil and surface water environments.
    Matched MeSH terms: Salmonella typhi/drug effects; Salmonella typhi/growth & development
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