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  1. Fulltext Imported cases of chloramphenicol resistant Salmonella typhi
    Cheong YM, Jegathesan M
    Med J Malaysia, 1992 Dec;47(4):331.
    PMID: 1303490
    Matched MeSH terms: Salmonella typhi/drug effects*
  2. Fulltext First isolates of chloramphenicol resistant S. typhi in Malaysia
    Jegathesan M, Khor SY
    Med J Malaysia, 1980 Jun;34(4):395-8.
    PMID: 7219270
    Four strains of S. typhi isolated in Malaysia were found to show resistance to chloramphenicol and other antibiotics. In two of these strains it was possible to show that this resistance was transferable.
    This problem which is widespread in neighbouring countries and undetected in Malaysia till recently has now been shown to exist in this country. Fears that the incidence of such strains will increase in the future are expressed and the need for vigilance is emphasised.
    Matched MeSH terms: Salmonella typhi/drug effects
  3. Fulltext Plasmid-mediated transferable chloramphenicol and tetracycline resistance in Salmonella typhi (Vi phage type 25) isolated in Peninsular Malaysia
    Koh CL, Lim ME, Wong YH
    Med J Malaysia, 1983 Dec;38(4):320-4.
    PMID: 6599991
    A clinical isolate of Salmonella typhi (Vi phage type 25), resistant to chloramphenicol, streptomycin and tetracycline, was examined for the presence of R plasmids. Results from conjugation, agarose gel electrophoresis and transformation experiments indicated that it harboured a single large self-transmissible R plasmid which coded for both the chloramphenicol and tetracycline resistance traits.
    Matched MeSH terms: Salmonella typhi/drug effects
  4. Effect of reduced graphene oxide-hybridized ZnO thin films on the photoinactivation of Staphylococcus aureus and Salmonella enterica serovar Typhi
    Teh SJ, Yeoh SL, Lee KM, Lai CW, Abdul Hamid SB, Thong KL
    J. Photochem. Photobiol. B, Biol., 2016 Aug;161:25-33.
    PMID: 27203568 DOI: 10.1016/j.jphotobiol.2016.05.013
    The immobilization of photocatalyst nanoparticles on a solid substrate is an important aspect for improved post-treatment separation and photocatalyst reactor design. In this study, we report the simple preparation of reduced graphene oxide (rGO)-hybridized zinc oxide (ZnO) thin films using a one-step electrochemical deposition, and investigated the effect of rGO-hybridization on the photoinactivation efficiency of ZnO thin films towards Staphylococcus aureus (S. aureus) and Salmonella enterica serovar Typhi (S. Typhi) as target bacterial pathogens. Field-emission scanning electron microscopy (FESEM) revealed the formation of geometric, hexagonal flakes of ZnO on the ITO glass substrate, as well as the incorporation of rGO with ZnO in the rGO/ZnO thin film. Raman spectroscopy indicated the successful incorporation of rGO with ZnO during the electrodeposition process. Photoluminescence (PL) spectroscopy indicates that rGO hybridization with ZnO increases the amount of oxygen vacancies, evidenced by the shift of visible PL peak at 650 to 500nm. The photoinactivation experiments showed that the thin films were able to reduce the bacterial cell density of Staph. aureus and S. Typhi from an initial concentration of approximately 10(8) to 10(3)CFU/mL within 15min. The rGO/ZnO thin film increased the photoinactivation rate for S. aureus (log[N/No]) from -5.1 (ZnO) to -5.9. In contrast, the application of rGO/ZnO thin film towards the photoinactivation of S. Typhi did not improve its photoinactivation rate, compared to the ZnO thin film. We may summarise that (1) rGO/ZnO was effective to accelerate the photoinactivation of S. aureus but showed no difference to improve the photoinactivation of S. Typhi, in comparison to the performance of ZnO thin films, and (2) the photoinactivation in the presence of ZnO and rGO/ZnO was by ROS damage to the extracellular wall.
    Matched MeSH terms: Salmonella typhi/drug effects*
  5. Typhoid fever--important issues still remain
    Pang T, Levine MM, Ivanoff B, Wain J, Finlay BB
    Trends Microbiol., 1998 Apr;6(4):131-3.
    PMID: 9587187
    Matched MeSH terms: Salmonella typhi/drug effects
  6. 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
  7. Fulltext Mutagenicity evaluation of Anastatica hierochuntica L. aqueous extract in vitro and in vivo
    Md Zin SR, Mohamed Z, Alshawsh MA, Wong WF, Kassim NM
    Exp Biol Med (Maywood), 2018 Feb;243(4):375-385.
    PMID: 29237294 DOI: 10.1177/1535370217748574
    Anastatica hierochuntica L. ( A. hierochuntica), a folk medicinal plant, was evaluated for mutagenic potential via in vitro and in vivo assays. The in vitro assay was conducted according to modified Ames test, while the in vivo study was performed according to Organisation for Economic Co-operation and Development guideline for mammalian erythrocyte micronucleus assay. Four groups ( n= 5 males and 5 females per group) Sprague Dawley rats were randomly chosen as the negative control, positive control (received a single intramuscular injection of cyclophosphamide 50 mg/kg), 1000 and, 2000 mg/kg A. hierochuntica aqueous extracts. All groups except the positive control were treated orally for three days. Findings of the in vitro assay showed mutagenic potential of AHAE at 0.04 and 0.2 mg/ml. However, no mutagenic effect was demonstrated in the in vivo study up to 2000 mg/kg. No significant reduction in the polychromatic and normochromatic erythrocytes ratio was noted in any of the groups. Meanwhile, high micronucleated polychromatic erythrocytes frequency was seen in cyclophosphamide-treated group only. These findings could perhaps be due to insufficient dosage of A. hierochuntica aqueous extracts to cause genetic damage on the bone marrow target cells. Further acute and chronic in vivo toxicity studies may be required to draw pertinent conclusion on the safety aspect of A. hierochuntica aqueous extracts consumption. Impact statement In this paper, we report on the mutagenicity evaluation of Anastatica hierochuntica aqueous extract. This is a significant research in view of the popularity of this herb consumption by the people across the globe despite of limited scientific evidence on its toxicity potential. This study is intended to encourage more extensive related research in order to provide sufficient evidence and guidance for determining its safe dosage.
    Matched MeSH terms: Salmonella typhi/drug effects
  8. Antibacterial effect of the red sea soft coral Sarcophyton trocheliophorum
    Gomaa MN, Soliman K, Ayesh A, Abd El-Wahed A, Hamza Z, Mansour HM, et al.
    Nat Prod Res, 2016;30(6):729-34.
    PMID: 26186031 DOI: 10.1080/14786419.2015.1040991
    The marine soft corals Sarcophyton trocheliophorum crude extracts possessed antimicrobial activity towards pathogenic bacterial strains, i.e. Bacillus cereus, Salmonella typhi, Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa. Bioassay-guided fractionation indicated that the antimicrobial effect was due to the presence of terpenoid bioactive derivatives. Further biological assays of the n-hexane fractions were carried out using turbidity assay, inhibition zone assay and minimum inhibitory concentration for investigating the growth-inhibition effect towards the Gram-positive and Gram-negative bacteria. The fractions were screened and the structure of the isolated compound was justified by interpretation of the spectroscopic data, mainly mass spectrometry (GC-MS). The structure was assigned as (5S)-3-[(3E,5S)-5-hydroxy-3-hepten-6-yn-1-yl]-5-methyl-2(5H)-furanone and was effective at concentrations as low as 0.20 mg/mL. The above findings, in the course of our ongoing research on marine products, may implicate that the profound anti-microbial activity of the S. trocheliophorum soft corals, inhabiting the red sea reefs, is attributed to the presence of growth-inhibiting secondary metabolites mainly terpenoids.
    Matched MeSH terms: Salmonella typhi/drug effects
  9. Multidrug-resistant strains of Salmonella enterica serotype typhi are genetically homogenous and coexist with antibiotic-sensitive strains as distinct, independent clones
    Thong KL, Bhutta ZA, Pang T
    Int J Infect Dis, 2000;4(4):194-7.
    PMID: 11231181
    OBJECTIVE: The goal of this study was to report the molecular analysis of antibiotic-sensitive and multidrug-resistant (MDR) strains of Salmonella typhi, using pulsed-field gel electrophoresis (PFGE), with a particular emphasis on the coexistence of these strains in a typhoid-endemic region of Karachi, Pakistan.

    METHODS: One hundred isolates of S. typhi in humans (50 MDR and 50 antibiotic-sensitive isolates) from sporadic cases of typhoid fever were analyzed by Vi-phage typing, antibiograms and PFGE.

    RESULTS: The MDR S. typhi strains were resistant to ampicillin, chloramphenicol, and trimethoprim-sulfamethoxazole. Analysis by PFGE showed that 50 MDR isolates of S. typhi had a single, homogenous PFGE profile, which was distinctly different from that of 50 antibiotic-sensitive isolates obtained in the same time frame from the same area. This latter group of isolates showed much greater diversity of PFGE profiles, as has been observed in other endemic regions.

    CONCLUSIONS: Multidrug-resistant and antibiotic-susceptible strains of S. typhi can coexist in endemic areas as epidemiologically independent pathogens and are not in competition for continued persistence and transmission.

    Matched MeSH terms: Salmonella typhi/drug effects*
  10. Travellers take heed: Outbreak of extensively drug resistant (XDR) typhoid fever in Pakistan and a warning from the US CDC
    Saleem Z, Hassali MA
    Travel Med Infect Dis, 2018 10 16;27:127.
    PMID: 30339826 DOI: 10.1016/j.tmaid.2018.10.013
    Matched MeSH terms: Salmonella typhi/drug effects
  11. Fulltext Isolation, Structure Elucidation and In Silico Prediction of Potential Drug-Like Flavonoids from Onosma chitralicum Targeted towards Functionally Important Proteins of Drug-Resistant Bad Bugs
    Khan SA, Khan SU, Fozia, Ullah N, Shah M, Ullah R, et al.
    Molecules, 2021 Apr 02;26(7).
    PMID: 33918531 DOI: 10.3390/molecules26072048
    Admittedly, the disastrous emergence of drug resistance in prokaryotic and eukaryotic human pathogens has created an urgent need to develop novel chemotherapeutic agents. Onosma chitralicum is a source of traditional medicine with cooling, laxative, and anthelmintic effects. The objective of the current research was to analyze the biological potential of Onosma chitralicum, and to isolate and characterize the chemical constituents of the plant. The crude extracts of the plant prepared with different solvents, such as aqueous, hexane, chloroform, ethyl acetate, and butanol, were subjected to antimicrobial activities. Results corroborate that crude (methanol), EtoAc, and n-C6H14 fractions were more active against bacterial strains. Among these fractions, the EtoAc fraction was found more potent. The EtoAc fraction was the most active against the selected microbes, which was subjected to successive column chromatography, and the resultant compounds 1 to 7 were isolated. Different techniques, such as UV, IR, and NMR, were used to characterize the structures of the isolated compounds 1-7. All the isolated pure compounds (1-7) were tested for their antimicrobial potential. Compounds 1 (4',8-dimethoxy-7-hydroxyisoflavone), 6 (5,3',3-trihydroxy-7,4'-dimethoxyflavanone), and 7 (5',7,8-trihydroxy-6,3',4'-trimethoxyflavanone) were found to be more active against Staphylococcus aureus and Salmonella Typhi. Compound 1 inhibited S. typhi and S. aureus to 10 ± 0.21 mm and 10 ± 0.45 mm, whereas compound 6 showed inhibition to 10 ± 0.77 mm and 9 ± 0.20 mm, respectively. Compound 7 inhibited S. aureus to 6 ± 0.36 mm. Compounds 6 and 7 showed significant antibacterial potential, and the structure-activity relationship also justifies their binding to the bacterial enzymes, i.e., beta-hydroxyacyl dehydratase (HadAB complex) and tyrosyl-tRNA synthetase. Both bacterial enzymes are potential drug targets. Further, the isolated compounds were found to be active against the tested fungal strains. Whereas docking identified compound 7, the best binder to the lanosterol 14α-demethylase (an essential fungal cell membrane synthesizing enzyme), reported as an antifungal fluconazole binding enzyme. Based on our isolation-linked preliminary structure-activity relationship (SAR) data, we conclude that O. chitralicum can be a good source of natural compounds for drug development against some potential enzyme targets.
    Matched MeSH terms: Salmonella typhi/drug effects*
  12. 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: Salmonella typhi/drug effects
  13. Fulltext Paradigm Shift in Drug Re-purposing From Phenalenone to Phenaleno-Furanone to Combat Multi-Drug Resistant Salmonella enterica Serovar Typhi
    Mujawar S, Gatherer D, Lahiri C
    Front Cell Infect Microbiol, 2018;8:402.
    PMID: 30488026 DOI: 10.3389/fcimb.2018.00402
    Over recent years, typhoid fever has gained increasing attention with several cases reporting treatment failure due to multidrug resistant (MDR) strains of Salmonella enterica serovar Typhi. While new drug development strategies are being devised to combat the threat posed by these MDR pathogens, drug repurposing or repositioning has become a good alternative. The latter is considered mainly due to its capacity for saving sufficient time and effort for pre-clinical and optimization studies. Owing to the possibility of an unsuccessful repositioning, due to the mismatch in the optimization of the drug ligand for the changed biochemical properties of "old" and "new" targets, we have chosen a "targeted" approach of adopting a combined chemical moiety-based drug repurposing. Using small molecules selected from a combination of earlier approved drugs having phenalenone and furanone moieties, we have computationally delineated a step-wise approach to drug design against MDR Salmonella. We utilized our network analysis-based pre-identified, essential chaperone protein, SicA, which regulates the folding and quality of several secretory proteins including the Hsp70 chaperone, SigE. To this end, another crucial chaperone protein, Hsp70 DnaK, was also considered due to its importance for pathogen survival under the stress conditions typically encountered during antibiotic therapies. These were docked with the 19 marketed anti-typhoid drugs along with two phenalenone-furanone derivatives, 15 non-related drugs which showed 70% similarity to phenalenone and furanone derivatives and other analogous small molecules. Furthermore, molecular dynamics simulation studies were performed to check the stability of the protein-drug complexes. Our results showed the best binding interaction and stability, under the parameters of a virtual human body environment, with XR770, a phenaleno-furanone moiety based derivative. We therefore propose XR770, for repurposing for therapeutic intervention against emerging and significant drug resistance conferred by pathogenic Salmonella strains.
    Matched MeSH terms: Salmonella typhi/drug effects*
  14. Synthesis, spectral analysis and biological evaluation of 2-{[(morpholin-4-yl)ethyl]thio}-5-phenyl/aryl-1,3,4-oxadiazole derivatives
    Ur-Rehman A, Khan SG, Naqvi SAR, Ahmad M, Akhtar N, Bokhari TH, et al.
    Pak J Pharm Sci, 2021 Jan;34(1(Special)):441-446.
    PMID: 34275792
    A series of new derivatives of 4-(2-chloroethyl)morpholine hydrochloride (5) were efficiently synthesized. Briefly, different aromatic organic acids (1a-f) were refluxed to acquire respective esters (2a-f) using conc. H2SO4 as catalyst. The esters were subjected to nucleophillic substitution by monohydrated hydrazine to acquire hydrazides (3a-f). The hydrazides were cyclized with CS2 in the presence of KOH to yield corresponding oxadiazoles (4a-f). Finally, the derivatives, 6a-f, were prepared by reacting oxadiazoles (4a-f) with 5 using NaH as activator. Structures of all the derivatives were elucidated through 1D-NMR EI-MS and IR spectral data. All these molecules were subjected to antibacterial and hemolytic activities and showed good antibacterial and hemolytic potential relative to the reference standards.
    Matched MeSH terms: Salmonella typhi/drug effects
  15. New anti-bacterial halogenated tricyclic sesquiterpenes from Bornean Laurencia majuscula (Harvey) Lucas
    Kamada T, Phan CS, Vairappan CS
    Nat Prod Res, 2019 Feb;33(4):464-471.
    PMID: 29092618 DOI: 10.1080/14786419.2017.1396593
    Three new halogenated tricyclic sesquiterpenes, omphalaurediol (1), rhodolaurenones B (2) and C (3) were isolated together with nine known haloganated sesquiterpenes such as rhodolaurenone A (4), rhodolaureol (5), isorhodolaureol (6), (-)-laurencenone D (7), elatol (8), (+)-deschloroelatol (9), cartilagineol (10), (+)-laurencenone B (11) and 2-chloro-3-hydroxy-α-chamigren-9-one (12) from a population of Bornean red algae Laurencia majuscula. The structures of three new metabolites were determined based on their spectroscopic data (IR, 1D and 2D NMR, and MS). These compounds showed antibacterial activity against three human pathogenic bacteria (Escherichia coli, Salmonella typhi and Vibrio cholera).
    Matched MeSH terms: Salmonella typhi/drug effects
  16. Analysis of plasmid and chromosomal DNA of multidrug-resistant Salmonella enterica serovar typhi from Asia
    Mirza S, Kariuki S, Mamun KZ, Beeching NJ, Hart CA
    J Clin Microbiol, 2000 Apr;38(4):1449-52.
    PMID: 10747124
    Molecular analysis of chromosomal DNA from 193 multidrug-resistant (MDR) Salmonella enterica serovar Typhi isolates from 1990 to 1995 from Pakistan, Kuwait, Malaysia, Bangladesh, and India produced a total of five major different pulsed-field gel electrophoresis (PFGE) patterns. Even within a particular country MDR S. enterica serovar Typhi DNA was found to be in different PFGE groups. Similar self-transferable 98-MDa plasmids belonging to either incompatibility group incHI1 or incHI1/FIIA were implicated in the MDR phenotype in S. enterica serovar Typhi isolates from all the locations except Quetta, Pakistan, where the majority were of incFIA. A total of five different PFGE genotypes with six different plasmids, based on incompatibility and restriction endonuclease analysis groups, were found among these MDR S. enterica serovar Typhi isolates.
    Matched MeSH terms: Salmonella typhi/drug effects*
  17. Multiple drug resistance and the presence of R factors in enteric pathogens
    Sng EH, Lam S
    Med J Malaya, 1971 Jun;25(4):301-4.
    PMID: 4261307
    Matched MeSH terms: Salmonella typhi/drug effects
  18. Fulltext The burden of typhoid fever in Klang Valley, Malaysia, 2011-2015
    Muhammad EN, Abdul Mutalip MH, Hasim MH, Paiwai F, Pan S, Mahmud MAF, et al.
    BMC Infect Dis, 2020 Nov 16;20(1):843.
    PMID: 33198646 DOI: 10.1186/s12879-020-05500-x
    BACKGROUND: Typhoid fever causes global morbidity and mortality and is a significant health burden, particularly in low- and middle-income countries. The direct fecal-oral route is the main transmission mode, but indirect environmental transmission could occur, particularly in urban settings. This study aimed to investigate the burden and trend of typhoid fever, reporting the coverage system between government and private practice and pattern of multidrug-resistant (MDR) typhoid cases in the urban Klang Valley area from 2011 to 2015.

    METHODS: The data from a cross-sectional study retrieved from the e-Notifikasi System, a national reporting system for communicable diseases provided by the Disease Control Division, Ministry of Health Malaysia and secondary data of all the typhoid cases were obtained from the public and private hospitals and laboratories in Klang Valley. Descriptive analysis was performed to examine the sociodemographic characteristics, spatial mapping was conducted to examine trends, and the crude incidence rates of confirmed typhoid cases and percentage of reporting coverage were calculated. Significant differences between MDR and non-MDR Salmonella typhi were determined in the patient's sociodemographic characteristics, which were analyzed using χ2 test. P values Salmonella typhi. Statistical significance was found in gender, citizenship and ethnicity regarding MDR Salmonella typhi (p = 0.004, p = 0.008 and p = 0.034, respectively).

    CONCLUSIONS: The local transmission of typhoid is still prevalent in the Klang Valley despite rapid urbanization and development in recent years. These findings are essential for policy makers to plan and implement focused and effective preventative activities to curb typhoid infection in urban areas.

    Matched MeSH terms: Salmonella typhi/drug effects
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