Displaying publications 1 - 20 of 72 in total

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  1. Whole-Genome Sequence of Salmonella enterica subsp. enterica Serovar Typhimurium Strain UPM 260, Isolated from a Broiler Chicken in Perak, Malaysia
    Roslan NS, Jabeen S, Mat Isa N, Omar AR, Bejo MH, Ideris A
    Genome Announc, 2017 Nov 16;5(46).
    PMID: 29146857 DOI: 10.1128/genomeA.01272-17
    Salmonella enterica subsp. enterica serovar Typhimurium is one of several well-categorized Salmonella serotypes recognized globally. Here, we report the whole-genome sequence of S Typhimurium strain UPM 260, isolated from a broiler chicken.
    Matched MeSH terms: Salmonella typhimurium
  2. Effect of natural antibacterial clays against single biofilm formation by Staphylococcus aureus and Salmonella Typhimurium bacteria on a stainless-steel surface
    Wan Omar WH, Mahyudin NA, Azmi NN, Mahmud Ab Rashid NK, Ismail R, Mohd Yusoff MHY, et al.
    Int J Food Microbiol, 2023 Jun 02;394:110184.
    PMID: 36996693 DOI: 10.1016/j.ijfoodmicro.2023.110184
    Staphylococcus aureus and Salmonella Typhimurium have a propensity to develop biofilms on food contact surfaces, such as stainless-steel, that persist despite rigorous cleaning and sanitizing procedures. Since both bacterial species pose a significant public health risk within the food chain, improved anti-biofilm measures are needed. This study examined the potential of clays as antibacterial and anti-biofilm agents against these two pathogens on appropriate contact surfaces. Natural soil was processed to yield leachates and suspensions of both untreated and treated clays. Soil particle size, pH, cation-exchange capacity, and metal ions were characterized to assess their importance in bacterial killing. Initial antibacterial screening was performed on nine distinct types of natural Malaysian soil using a disk diffusion assay. Untreated leachate from Kuala Gula and Kuala Kangsar clays were found to inhibit S. aureus (7.75 ± 0.25 mm) and Salmonella Typhimurium (11.85 ± 1.63 mm), respectively. The treated Kuala Gula suspension (50.0 and 25.0 %) reduced S. aureus biofilms by 4.4 and 4.2 log at 24 and 6 h, respectively, while treated Kuala Kangsar suspension (12.5 %) by a 4.16 log reduction at 6 h. Although less effective, the treated Kuala Gula leachate (50.0 %) was effective in removing Salmonella Typhimurium biofilm with a decrease of >3 log in 24 h. In contrast to Kuala Kangsar clays, the treated Kuala Gula clays contained a much higher soluble metal content, especially Al (301.05 ± 0.45 ppm), Fe (691.83 ± 4.80 ppm) and Mg (88.44 ± 0.47 ppm). Elimination of S. aureus biofilms correlated with the presence of Fe, Cu, Pb, Ni, Mn and Zn irrespective of the pH of the leachate. Our findings demonstrate that a treated suspension is the most effective for eradication of S. aureus biofilms with a potential as a sanitizer-tolerant, natural antibacterial against biofilms for applications in the food industry.
    Matched MeSH terms: Salmonella typhimurium*
  3. Mutagenicity Assessment of Homologous Series of Methyl Ester Sulphonates (MES) Using the Bacterial Reverse Mutation (Ames) Test
    Yusof YA, Azizul Hasan ZA, Abd Maurad Z
    Int J Toxicol, 2024;43(2):157-164.
    PMID: 38048784 DOI: 10.1177/10915818231217041
    Methyl ester sulphonate (MES) is an anionic surfactant that is suitable to be used as an active ingredient in household products. Four palm-based MES compounds with various carbon chains, namely C12, C14, C16 and C16/18 MES, were assayed by the in vitro bacterial reverse mutation (Ames) test in the Salmonella typhimurium strains TA98, TA100, TA1535, and TA1537 and the Escherichia coli strain WP2 uvrA, with the aim of establishing the safety data of the compounds, specifically their mutagenicity. The test was also carried out on linear alkylbenzene sulphonate (LAS) for comparison. The plate incorporation method was conducted according to the Organization for Economic Cooperation and Development (OECD) Test Guideline 471. All compounds were tested at five analysable non-cytotoxic concentrations, varying from .001 mg/plate to 5 mg/plate, with and without S-9 metabolic activation. All tested concentrations showed no significant increase in the number of revertant colonies compared to revertant colonies of the negative control. The Ames test indicated that each concentration of C12, C14, C16, C16/18 MES, and LAS used in this study induced neither base-pair substitutions nor frame-shift mutations in the S. typhimurium strains TA98, TA100, TA1535, and TA1537 and the E. coli strain WP2 uvrA. The results showed that C12, C14, C16 and C16/18 MES have no potential mutagenic properties in the presence and absence of S-9 metabolic activation, similarly to LAS. Therefore, the MES is safe to be used as an alternative to petroleum-based surfactants for household cleaning products.
    Matched MeSH terms: Salmonella typhimurium/genetics
  4. False-positive widal test in nontyphoid Salmonella infections
    Pang T, Pothocheary SD
    Southeast Asian J. Trop. Med. Public Health, 1989 Mar;20(1):163-4.
    PMID: 2672364
    Matched MeSH terms: Salmonella typhimurium/isolation & purification
  5. Simple and rapid detection of Salmonella strains by direct PCR amplification of the hilA gene
    Pathmanathan SG, Cardona-Castro N, Sánchez-Jiménez MM, Correa-Ochoa MM, Puthucheary SD, Thong KL
    J Med Microbiol, 2003 Sep;52(Pt 9):773-6.
    PMID: 12909653
    The suitability of a PCR procedure using a pair of primers targeting the hilA gene was evaluated as a means of detecting Salmonella species. A total of 33 Salmonella strains from 27 serovars and 15 non-Salmonella strains from eight different genera were included. PCR with all the Salmonella strains produced a 784 bp DNA fragment that was absent from all the non-Salmonella strains tested. The detection limit of the PCR was 100 pg with genomic DNA and 3 x 10(4) c.f.u. ml(-1) with serial dilutions of bacterial culture. An enrichment-PCR method was further developed to test the sensitivity of the hilA primers for the detection of Salmonella in faecal samples spiked with different concentrations of Salmonella choleraesuis subsp. choleraesuis serovar Typhimurium. The method described allowed the detection of Salmonella Typhimurium in faecal samples at a concentration of 3 x 10(2) c.f.u. ml(-1). In conclusion, the hilA primers are specific for Salmonella species and the PCR method presented may be suitable for the detection of Salmonella in faeces.
    Matched MeSH terms: Salmonella typhimurium/classification; Salmonella typhimurium/genetics; Salmonella typhimurium/isolation & purification
  6. Fulltext Whole-Genome Sequences of Salmonella enterica subsp. enterica Serovar Typhimurium Strains TT6675 and TT9097 Employed in the Isolation and Characterization of a Giant Phage Mutant Collection
    Gan HM, Eng WWH, Barton MK, Adams LE, Samsudin NA, Bartl AJ, et al.
    Genome Announc, 2017 Aug 24;5(34).
    PMID: 28839032 DOI: 10.1128/genomeA.00857-17
    We report here the genome sequences of Salmonella enterica subsp. enterica serovar Typhimurium strains TT6675 and TT9097, which we utilize for genetic analyses of giant bacterial viruses. Our analyses identified several genetic variations between the two strains, most significantly confirming strain TT6675 as a serine suppressor and TT9097 as a nonsuppressor.
    Matched MeSH terms: Salmonella typhimurium
  7. Lacto-fermented garlic sauce improved the quality and extended the shelf life of lamb meat under the chilled condition
    Hajar-Azhari S, Daud N, Muhialdin BJ, Joghee N, Kadum H, Meor Hussin AS
    Int J Food Microbiol, 2023 Jun 16;395:110190.
    PMID: 37030193 DOI: 10.1016/j.ijfoodmicro.2023.110190
    This study evaluated the potential of fermented garlic as a marinated lamb sauce ingredient to improve the quality and shelf life of chilled lamb. Garlic was subjected to Lacto-fermentation for 72 h at 37 °C using Lacticaseibacillus casei. The 1H NMR metabolomics profile showed the presence of eight amino acids and five organic acids in fermented garlic, indicating the attribution to the antioxidant and antimicrobial activities. The FRAP and DPPH assays of fermented garlic revealed antioxidant activities of 0.45 ± 0.09 mmol/100 g DW and 93.85 ± 0.02 %, respectively. Meanwhile, fermented garlic inhibited the growth of Escherichia coli (95 %), Staphylococcus aureus (99 %) and Salmonella Typhimurium (98 %). When fermented garlic was added to the marinade sauce, it successfully reduced the microbial load of lamb meat by 0.5 log CFU/g after 3 days of storage. There were no significant differences in color between the control and marinated lamb after 3 days of marinating in a sauce formulated with fermented garlic. Furthermore, marinated lamb significantly improved water-holding capacity, texture, juiciness, and overall acceptance. These findings indicated a potential addition of fermented garlic in marinade lamb sauce recipes to improve the quality and safety of meat products.
    Matched MeSH terms: Salmonella typhimurium
  8. Genotoxicity evaluation of locally produced dental porcelain--an in vitro study using the Ames and Comet assays
    Noushad M, Kannan TP, Husein A, Abdullah H, Ismail AR
    Toxicol In Vitro, 2009 Sep;23(6):1145-50.
    PMID: 19505568 DOI: 10.1016/j.tiv.2009.05.025
    The aim of this study was to determine the genotoxicity of a locally produced dental porcelain (Universiti Sains Malaysia, Malaysia) using the Ames and Comet assays. In the Ames assay, four genotypic variants of the Salmonella strains (TA98, TA100, TA1537 and TA1535) carrying mutations in several genes were used. The dental porcelain was incubated with these four strains in five different doses both in the presence and absence of metabolic activation (S9) and the result was assessed based on the number of revertant colonies. Concurrently, appropriate positive controls were used so as to validate the test. The average number of revertant colonies per plate treated with locally produced dental porcelain was less than double as compared to that of negative control. In the Comet assay, L929 (CCL-1 ATCC, USA) mouse fibroblast cells were treated with the dental porcelain in three different concentrations along with concurrent negative and positive controls. The tail moment which was used as a measurement of DNA damage was almost equal to that of the negative control, suggesting that the locally produced dental porcelain did not induce any DNA damage. The results indicated that the locally produced dental porcelain is non-genotoxic under the present test conditions.
    Matched MeSH terms: Salmonella typhimurium/drug effects*; Salmonella typhimurium/genetics
  9. 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 typhimurium/classification; Salmonella typhimurium/isolation & purification
  10. Fulltext Mutagenic and cytotoxic properties of three herbal plants from Southeast Asia
    Mohd-Fuat AR, Kofi EA, Allan GG
    Trop Biomed, 2007 Dec;24(2):49-59.
    PMID: 18209708 MyJurnal
    Three popular medicinal plants regarded as improving human sexual function in some parts of Southeast Asia were analysed for their mutagenic properties using modified Ames test (fluctuation test). Extract of one of the plants, Tacca integrifolia Ker-Gawl., was found to be mutagenic using Salmonella typhimurium strains TA98 and TA100. Extract of T. integrifolia, Eurycoma longifolia Jack and Helmintostachys zeylanica (L.) Hook were cytotoxic to human cell lines, Hep2 and HFL1, with IC50 ranging from 11 mug/ml to 55 mug/ml. Extract of E. longifolia was the most cytotoxic with IC50 of 11 mug/ml and 13 mug/ml on Hep2 and HFL1 cell lines respectively. Combined extract of T. integrifolia and H. zeylanica was more cytotoxic than single extract on both Hep2 and HFL1 cell lines while combined extract of E. longifolia and H. zeylanica was more cytotoxic than single extract on Hep2 cell lines. Under the conditions of this study it can be concluded that T. integrifolia is mutagenic and the combined extracts of the medicinal plants was highly cytotoxic.
    Matched MeSH terms: Salmonella typhimurium/drug effects*; Salmonella typhimurium/genetics
  11. Animal salmonellosis in peninsular Malaysia. II. Annual and zoological distribution of Salmonella serotypes over the 10-year period 1966-1975
    Joseph PG, Anwar M, Jegathesan M
    Am J Trop Med Hyg, 1978 May;27(3):562-6.
    PMID: 354419
    A total of 860 Salmonella isolations were made in Peninsular Malaysia from 15 animal species (domestic and wild), eggs, molluscs, flies, and animal feed. The isolations were distributed among 31 serotypes in eight groups. The most common serotype isolated was Salmonella pullorum, followed by S. choleraesuis and S. infantis. S. typhimurium had the widest zoological distribution. The importance of controlling animal salmonellosis is emphasized.
    Matched MeSH terms: Salmonella typhimurium/classification; Salmonella typhimurium/isolation & purification
  12. Fulltext House Sparrows Do Not Constitute a Significant Salmonella Typhimurium Reservoir across Urban Gradients in Flanders, Belgium
    Rouffaer LO, Lens L, Haesendonck R, Teyssier A, Hudin NS, Strubbe D, et al.
    PLoS One, 2016;11(5):e0155366.
    PMID: 27168186 DOI: 10.1371/journal.pone.0155366
    In recent decades major declines in urban house sparrow (Passer domesticus) populations have been observed in north-western European cities, whereas suburban and rural house sparrow populations have remained relatively stable or are recovering from previous declines. Differential exposure to avian pathogens known to cause epidemics in house sparrows may in part explain this spatial pattern of declines. Here we investigate the potential effect of urbanization on the development of a bacterial pathogen reservoir in free-ranging house sparrows. This was achieved by comparing the prevalence of Salmonella enterica subspecies enterica serotype Typhimurium in 364 apparently healthy house sparrows captured in urban, suburban and rural regions across Flanders, Belgium between September 2013 and March 2014. In addition 12 dead birds, received from bird rescue centers, were necropsied. The apparent absence of Salmonella Typhimurium in fecal samples of healthy birds, and the identification of only one house sparrow seropositive for Salmonella spp., suggests that during the winter of 2013-2014 these birds did not represent any considerable Salmonella Typhimurium reservoir in Belgium and thus may be considered naïve hosts, susceptible to clinical infection. This susceptibility is demonstrated by the isolation of two different Salmonella Typhimurium strains from two of the deceased house sparrows: one DT99, typically associated with disease in pigeons, and one DT195, previously associated with a passerine decline. The apparent absence (prevalence: <1.3%) of a reservoir in healthy house sparrows and the association of infection with clinical disease suggests that the impact of Salmonella Typhimurium on house sparrows is largely driven by the risk of exogenous exposure to pathogenic Salmonella Typhimurium strains. However, no inference could be made on a causal relationship between Salmonella infection and the observed house sparrow population declines.
    Matched MeSH terms: Salmonella typhimurium/pathogenicity*; Salmonella typhimurium/physiology
  13. Effects of temperature abuse on the survival, growth, and inactivation of Salmonella typhimurium in goat milk
    Migeemanathan S, Bhat R, Min-Tze L, Wan-Abdullah WN
    Foodborne Pathog Dis, 2011 Nov;8(11):1235-40.
    PMID: 21819211 DOI: 10.1089/fpd.2011.0945
    The growth and survival of Salmonella typhimurium in goat milk samples at different shifting temperatures were evaluated. The growth of S. typhimurium at lower temperatures (5°C, 10°C, and 15°C) exhibited bacteriostatic effects in milk, whereas at ambient temperature (25°C) and at 45°C, this pathogen luxuriantly grew throughout the 12-h stationary phase. At 50°C this pathogen was found to be thermotolerant and could still thrive in the milk. Overall, shifting temperatures from 37°C to 55°C and 60°C clearly indicated S. typhimurium to have reached complete elimination. The results demonstrated that the adaptation and survival of this pathogen directly depend on temperature stress. It is expected that the results will be useful to dairy industries for implementation of good manufacturing practices with a better hazard analysis critical control point approach to predict the microbial risk assessment and also benefit the consumers.
    Matched MeSH terms: Salmonella typhimurium/growth & development; Salmonella typhimurium/physiology*
  14. Anti-proliferative and mutagenic activities of aqueous and methanol extracts of leaves from Pereskia bleo (Kunth) DC (Cactaceae)
    Er HM, Cheng EH, Radhakrishnan AK
    J Ethnopharmacol, 2007 Sep 25;113(3):448-56.
    PMID: 17698306
    The anti-proliferative effects of the aqueous and methanol extracts of leaves of Pereskia bleo (Kunth) DC (Cactaceae) against a mouse mammary cancer cell line (4T1) and a normal mouse fibroblast cell line (NIH/3T3) were evaluated under an optimal (in culture medium containing 10% foetal bovine serum (FBS)) and a sub-optimal (in culture medium containing 0.5% FBS) conditions. Under the optimal condition, the aqueous extract showed a significant (p<0.05) anti-proliferative effect at 200 microg/mL and 300 microg/mL in 4T1 cells and 300 microg/mL in NIH/3T3 cells, whereas the methanol extract did not show any notable anti-proliferative effect in these cell lines, at any of the concentrations tested. Under the sub-optimal condition, the aqueous extract showed a significant (p<0.05) anti-proliferative effect at 200 microg/mL and 300 microg/mL in NIH/3T3 cells, whilst the methanol extract showed a significant (p<0.05) anti-proliferative effect at 200 microg/mL and 300 microg/mL in both cell lines. An upward trend of apoptosis was observed in both 4T1 and NIH/3T3 cells treated with increasing concentrations of the aqueous extract. The level of apoptosis observed at all the concentrations of the aqueous extract tested was consistently higher than necrosis. There was a significant (p<0.05) increase in the level of necrosis observed in the 4T1 cells treated with 300 microg/mL of the methanol extract. Generally, the level of necrosis was noted to be higher than that of apoptosis in the methanol extract-treated cells. The mutagenicity assay performed showed that in the absence of S-9 liver metabolic activation, the extract was not mutagenic up to the concentration of 165 microg/mL . However, in the presence of S-9 liver metabolic activation, the aqueous extract was mutagenic at all the concentrations tested. This study shows that both the aqueous and methanol extracts of the leaves from Pereskia bleo (Kunth) DC (Cactaceae) do not have appreciable anti-proliferative effect on the 4T1 and NIH/3T3 cells as the EC(50) values obtained are greater than 50 microg/mL when tested under optimal culture condition. Moreover, the aqueous extract may form mutagenic compound(s) upon the metabolisation by liver enzymes.
    Matched MeSH terms: Salmonella typhimurium/drug effects; Salmonella typhimurium/genetics
  15. Mutagenicity and preclinical safety assessment of the aqueous extract of Clinacanthus nutans leaves
    Farsi E, Esmailli K, Shafaei A, Moradi Khaniabadi P, Al Hindi B, Khadeer Ahamed MB, et al.
    Drug Chem Toxicol, 2016 Oct;39(4):461-73.
    PMID: 27033971 DOI: 10.3109/01480545.2016.1157810
    CONTEXT: Clinacanthus nutans (CN) is used traditionally for treating various illnesses. Robust safety data to support its use is lacking.

    OBJECTIVE: To evaluate the adverse effects of aqueous extract of CN leaves (AECNL).

    MATERIALS AND METHODS: The oral toxicity of the AECNL was tested following Organisation for Economic Co-operation and Development (OECD) guidelines. Mutagenicity (Ames test) of AECNL was evaluated using TA98 and TA100 Salmonella typhimurium strains.

    RESULTS: No mortality or morbidity was found in the animals upon single and repeated dose administration. However, significant body weight loss was observed at 2000 mg/kg during sub-chronic (90 d) exposure. In addition, increased eosinophil at 500 mg/kg and decreased serum alkaline phosphatase levels at 2000 mg/kg were observed in male rats. Variations in glucose and lipid profiles in treated groups were also observed compared to control. Ames test revealed no evidence of mutagenic or carcinogenic effects at 500 μg/well of AECNL.

    CONCLUSION: The median lethal dose (LD50) of the AECNL is >5000 mg/kg and the no-observed-adverse-effect level is identified to be greater than 2000 mg/kg/day in 90-d study.

    Matched MeSH terms: Salmonella typhimurium/drug effects*; Salmonella typhimurium/genetics
  16. Enhancement of anti-proliferative activities of Metformin, when combined with Celecoxib, without increasing DNA damage
    Ullah A, Ashraf M, Javeed A, Anjum AA, Attiq A, Ali S
    Environ Toxicol Pharmacol, 2016 Jul;45:227-34.
    PMID: 27327526 DOI: 10.1016/j.etap.2016.05.017
    Pathophysiological changes in diabetes like hyperglycemia, oxidative stress, insulin resistance and compensatory hyperinsulinemia predispose cells to malignant transformation and damage DNA repair mechanism. This study was designed to explore the potential synergistic toxic effects of anti-diabetic drug (Metformin), and an analgesic drug (Celecoxib) at cellular level. MTT assay run on Vero cell line revealed that the combinations of Metformin and Celecoxib augment the anti-proliferative effects, whereas Single cell gel electrophoresis spotlighted that Metformin produce non-significant DNA damage with the threshold concentration of 400μg/ml in peripheral blood mononuclear cells (lymphocytes and monocytes), while Celecoxib produced significant (P<0.05) DNA damage (class III comets) above the concentration of 75μg/ml, however the DNA damage or DNA tail protrusions by combinations of both drugs were less than what was observed with Celecoxib alone. Metformin or Celecoxib did not appear mutagenic against any mutant strains (TA 100 and TA 98) but their combination exhibited slight mutagenicity at much higher concentration. The results obtained at concentrations higher than the therapeutic level of drugs and reflect that Metformin in combination with Celecoxib synergistically inhibits the cell proliferation in a concentration dependent pattern. Since, this increase in cytotoxicity did not confer an increase in DNA damage; this combination could be adopted to inhibit the growth of malignant cell without producing any genotoxic or mutagenic effects at cellular level.
    Matched MeSH terms: Salmonella typhimurium/drug effects; Salmonella typhimurium/genetics
  17. Antibiofilm activity and mode of action of DMSO alone and its combination with afatinib against Gram-negative pathogens
    Yahya MFZR, Alias Z, Karsani SA
    Folia Microbiol (Praha), 2018 Jan;63(1):23-30.
    PMID: 28540585 DOI: 10.1007/s12223-017-0532-9
    Biofilms are complex microbial communities that tend to attach to either biotic or abiotic surface. Enclosed in a self-produced extracellular polymeric substance (EPS) matrix, the biofilms often cause persistent infections. The objective of this study was to investigate the antibiofilm activity of dimethyl sulfoxide (DMSO) and afatinib against Gram-negative pathogens. Test microorganisms used in this study were Escherichia coli ATCC 1299, Pseudomonas aeruginosa ATCC 10145, and Salmonella typhimurium ATCC 14028. Biofilms were developed in 96-well microplate at 37°C for 24 h. Following removal of non-adherent cells, analysis of biofilm viability, biofilm biomass, and extracellular polymeric substances (EPS) matrix were performed using resazurin assay, crystal violet assay, and attenuated total reflectance fourier transform infrared (ATR-FTIR) spectroscopy, respectively. Bradford protein assay was conducted to determine the total amount of EPS proteins. The results demonstrated that both 32% DMSO alone and its combination with 3.2 μg/mL afatinib were effective in killing biofilm cells and reducing biofilm biomass. IR spectral variations of EPS matrix of biofilms in the range between 1700 and 900 cm-1 were also observed. Reduction in EPS proteins verified the chemical modifications of EPS matrix. In conclusion, 32% DMSO alone and its combination with 3.2 μg/mL afatinib showed remarkable antibiofilm activities against Gram-negative pathogens. It was suggested that the biofilm inhibition was mediated by the chemical modification of EPS matrix.
    Matched MeSH terms: Salmonella typhimurium/drug effects*; Salmonella typhimurium/physiology
  18. Characterization of drug resistant Salmonella enterica serotype Typhimurium by antibiograms, plasmids, integrons, resistance genes and PFGE
    Benacer D, Thong KL, Watanabe H, Puthucheary SD
    J Microbiol Biotechnol, 2010 Jun;20(6):1042-52.
    PMID: 20622506
    Forty-seven Salmonella Typhimurium (33 zoonotic, 14 clinical) strains were tested for antimicrobial resistance using the standard disk diffusion method. Presence of relevant resistance genes and class 1 integrons were investigated by using PCR. Pulsed-field gel electrophoresis (PFGE) and plasmid profiling were carried out to determine the genomic diversity of Salmonella Typhimurium. Approximately 57.4% of S. Typhimurium were multidrug resistant (MDR) and showed high resistance rates to tetracycline (70.2%), sulphonamides (57.4%), streptomycin (53.1%), ampicillin (29.7%), nalidixic acid (27.6%), kanamycin (23.4%), chloramphenicol (21.2%) and trimethoprim (19.1%). Resistance towards cephalosporins was noted for cephalothin (27.6%), cephradine (21.2%), amoxicillin clavulanic acid (17.0%) and cephalexin (17.0%). Resistance genes, blaTEM, strA, aadA, sul1, sul2, tet(A), tet(B) and tet(C) were detected among the drug resistant strains. Thirty-three strains (70.2%) carried class 1 integrons, which were grouped in 9 different profiles. DNA sequencing identified sat, aadA, pse-1 and dfrA genes in variable regions on class 1 integrons. Thirty-five strains (74.4%) were subtyped to 22 different plasmid profiles, each with 1 - 6 plasmids (2.0 to 95 kb). PFGE subtyped the 47 strains into 39 profiles. In conclusion, high rates of multidrug-resistance were found among the Malaysian Salmonella Typhimurium strains. The emergence of multidrug-resistant Salmonella Typhimurium to cephalosporin antibiotics was also observed. The strains were very diverse and no persistent clone was observed. The emergence of MDR Salmonella Typhimurium is a worldwide problem and this report provides information for the better understanding of the prevalence and epidemiology of MDR S. Typhimurium in Malaysia.
    Matched MeSH terms: Salmonella typhimurium/classification; Salmonella typhimurium/drug effects*; Salmonella typhimurium/genetics*
  19. Fulltext Phytochemical and In Vitro Genotoxicity Studies of Standardized Ficus deltoidea var. kunstleri Aqueous Extract
    Muhammad H, Omar MH, Rasid ENI, Suhaimi SN, Mohkiar FH, Siu LM, et al.
    Plants (Basel), 2021 Feb 11;10(2).
    PMID: 33670296 DOI: 10.3390/plants10020343
    The present study was carried out to assess the genotoxicity potential of Ficus deltoidea var. kunstleri aqueous extract (FDAE) using standard in vitro assays. The DNA damage of V79B cells was measured using the alkaline comet assay treated at 0.1 mg/mL (IC10) and 0.3 mg/mL (IC25) of FDAE together with positive and negative controls. For in vitro micronucleus assay, the V79B cells were treated with FDAE at five different concentrations (5, 2.5, 1.25, 0.625, and 0.3125 mg/mL) with and without S9 mixture. The bacteria reverse mutation assay of FDAE was performed on Salmonella typhimurium strains TA98, 100, 1535, 1537, and Escherichia coli strain WP2uvrA using pre-incubation method in the presence or in the absence of an extrinsic metabolic system (S9 mixture). FDAE at 0.1 and 0.3 mg/mL significantly increased DNA damage in both comet tail and tail moment (p < 0.05). No significant changes were detected in the number of micronucleated cell when compared to control. Tested at the doses up to 5000 µg/plate, the FDAE did not increase the number of revertant colonies for all strains. In conclusion, further investigation needs to be conducted in animal model to confirm the non-genotoxicity activities of FDAE.
    Matched MeSH terms: Salmonella typhimurium
  20. Molecular characterization of Salmonella enterica serovar Typhimurium isolated from human, food, and animal sources in Malaysia
    Ngoi ST, Lindstedt BA, Watanabe H, Thong KL
    Jpn J Infect Dis, 2013;66(3):180-8.
    PMID: 23698477
    Salmonella Typhimurium is an important nontyphoidal Salmonella serovar associated with foodborne diseases in many parts of the world. This organism is the major causative agent of nontyphoidal salmonellosis in Malaysia. We aimed to investigate the genetic profiles of the strains isolated from clinical, zoonotic, and dietary sources in Malaysia using multilocus variable number tandem repeat analysis (MLVA) and pulsed-field gel electrophoresis (PFGE). By focusing on the 5 common variable number tandem repeat (VNTR) loci, we found that PFGE (D = 0.99) was more discriminative than MLVA (D = 0.76). The low MLVA score might be because of a lack of VNTR loci STTR6 (81.0%) and STTR10pl (76.2%). Both subtyping methods suggested that our S. Typhimurium strains were largely endemic with limited genetic variation. Furthermore, we observed that biphasic S. Typhimurium strains were dominant (99%) and multidrug resistance was prevalent (50%) within our sample pool. The most frequently observed phenotypes were resistance to compound sulfonamides (49%), tetracycline (51%), and streptomycin (52%). In this study, we documented the genetic relationship, antimicrobial resistance characteristics, and flagellar-phase dominance among S. Typhimurium strains found in Malaysia.
    Matched MeSH terms: Salmonella typhimurium/classification*; Salmonella typhimurium/genetics*; Salmonella typhimurium/isolation & purification
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