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  1. Fulltext Effects of Selected Herbicides on Growth and Nitrogen Fixing Activity of Stenotrophomonas maltophilia (Sb16)
    Nahi A, Othman R, Omar D, Ebrahimi M
    Pol J Microbiol, 2016 Aug 26;65(3):377-382.
    PMID: 29334074 DOI: 10.5604/17331331.1215618
    A study was carried out to determine the effects of paraquat, pretilachlor and 2, 4-D on growth and nitrogen fixing activity of Stenotrophomonas maltophilia (Sb16) and pH of Jensen's N-free medium. The growth of Sb16 and pH of medium were significantly reduced with full (X) and double (2X) doses of tested herbicides, but nitrogen fixing activity was decreased by 2X doses. The nitrogenase activity had the highest value in samples treated with 1/2X of 2, 4-D on fifth incubation day, but 2X of 2, 4-D had the most adverse effect. An inhibition in the growth and nitrogenase activity was recovered on the last days of incubation.
    Matched MeSH terms: Stenotrophomonas maltophilia/drug effects*; Stenotrophomonas maltophilia/enzymology; Stenotrophomonas maltophilia/growth & development*; Stenotrophomonas maltophilia/metabolism
  2. Fulltext Iron and Virulence in Stenotrophomonas Maltophilia: All We Know So Far
    Kalidasan V, Joseph N, Kumar S, Awang Hamat R, Neela VK
    Front Cell Infect Microbiol, 2018;8:401.
    PMID: 30483485 DOI: 10.3389/fcimb.2018.00401
    Stenotrophomonas maltophilia is a multi-drug-resistant global opportunistic nosocomial pathogen, which possesses a huge number of virulence factors and antibiotics resistance characteristics. Iron has a crucial contribution toward growth and development, cell growth and proliferation, and pathogenicity. The bacterium found to acquire iron for its cellular process through the expression of two iron acquisition systems. Two distinct pathways for iron acquisition are encoded by the S. maltophilia genome-a siderophore-and heme-mediated iron uptake system. The entAFDBEC operon directs the production of the enterobactin siderophore of catecholate in nature, while heme uptake relies on hgbBC and potentially hmuRSTUV operon. Fur and sigma factors are regulators of S. maltophilia under iron-limited condition. Iron potentially act as a signal which plays an important role in biofilm formation, extracellular polymeric substances (EPS), extracellular enzymes production, oxidative stress response, diffusible signal factor (DSF) and siderophore production in S. maltophilia. This review summarizes the current knowledge of iron acquisition in S. maltophilia and the critical role of iron in relation to its pathogenicity.
    Matched MeSH terms: Stenotrophomonas maltophilia/genetics; Stenotrophomonas maltophilia/growth & development; Stenotrophomonas maltophilia/metabolism*; Stenotrophomonas maltophilia/pathogenicity
  3. Modified DNase tube test to detect DNase activity in Stenotrophomonas maltophilia
    Neela V, Thomas R, Rankouhi SZR, Karunanidhi A, Shueh CS, Hamat RA, et al.
    J Med Microbiol, 2012 Dec;61(Pt 12):1792-1794.
    PMID: 22956752 DOI: 10.1099/jmm.0.049403-0
    Matched MeSH terms: Stenotrophomonas maltophilia/enzymology*
  4. Stenotrophomonas maltophilia: pathogenesis model using Caenorhabditis elegans
    Thomas R, Hamat RA, Neela V
    J Med Microbiol, 2013 Nov;62(Pt 11):1777-1779.
    PMID: 23988629 DOI: 10.1099/jmm.0.063230-0
    Matched MeSH terms: Stenotrophomonas maltophilia/pathogenicity*
  5. Fulltext Twitching motility of Stenotrophomonas maltophilia under iron limitation: In-silico, phenotypic and proteomic approaches
    V K, Neela VK
    Virulence, 2020 Dec;11(1):104-112.
    PMID: 31957553 DOI: 10.1080/21505594.2020.1713649
    This study investigates the twitching ability of 28 clinical and five environmental strains of S. maltophilia grown under iron-depleted condition through in-silico, phenotypic and proteomics approaches. Rapid Annotations using Subsystem Technology (RAST) analysis revealed the presence of 21 targets of type IV pilus shared across S. maltophilia strains K279a, R551-3, D457 and JV3. The macroscopic twitching assay showed that only clinical isolates produced a zone of twitching with a mean of 22.00 mm under normal and 25.00 mm under iron-depleted conditions. (p = 0.002). Environmental isolates did not show any significant twitching activity in both conditions tested. Isobaric Tags for Relative and Absolute Quantification (ITRAQ) analysis showed altered expression of twitching motility protein PilT (99.08-fold change), flagellar biosynthesis protein FliC (20.14-fold change), and fimbrial protein (0.70-fold change) in response to iron-depleted condition. Most of the strains that have the ability to twitch under the normal condition, exhibit enhanced twitching during iron limitation.
    Matched MeSH terms: Stenotrophomonas maltophilia/metabolism*
  6. Simple, time saving pulsed-field gel electrophoresis protocol for the typing of Stenotrophomonas maltophilia
    Shueh CS, Neela V, Hussin S, Hamat RA
    J Microbiol Methods, 2013 Aug;94(2):141-143.
    PMID: 23756145 DOI: 10.1016/j.mimet.2013.06.001
    We developed a time-saving and cost-efficient Pulsed Field Gel Electrophoresis (PFGE) method for the typing of Stenotrophomonas maltophilia by modifying the conventional procedures. Our modifications related to the cell suspension preparation, lysis of bacterial cells in plugs, washing steps, and consumption of restriction enzyme. Although few rapid PFGE protocols on Gram-negative bacteria are available, the use of comparatively large amounts of costly reagents prompted us to look for other alternative. Hence, by considering the speed, simplicity, and relatively low cost, the modified protocol may be of more practical value than other established protocols in investigating S. maltophilia nosocomial outbreaks.
    Matched MeSH terms: Stenotrophomonas maltophilia/classification; Stenotrophomonas maltophilia/genetics; Stenotrophomonas maltophilia/isolation & purification*
  7. Fulltext Extracellular enzyme profiling of Stenotrophomonas maltophilia clinical isolates
    Thomas R, Hamat RA, Neela V
    Virulence, 2014 Feb 15;5(2):326-30.
    PMID: 24448556 DOI: 10.4161/viru.27724
    Matched MeSH terms: Stenotrophomonas maltophilia/enzymology*; Stenotrophomonas maltophilia/isolation & purification
  8. Fulltext In vitro antibacterial and antibiofilm activities of chlorogenic acid against clinical isolates of Stenotrophomonas maltophilia including the trimethoprim/sulfamethoxazole resistant strain
    Karunanidhi A, Thomas R, van Belkum A, Neela V
    Biomed Res Int, 2013;2013:392058.
    PMID: 23509719 DOI: 10.1155/2013/392058
    The in vitro antibacterial and antibiofilm activity of chlorogenic acid against clinical isolates of Stenotrophomonas maltophilia was investigated through disk diffusion, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), time-kill and biofilm assays. A total of 9 clinical S. maltophilia isolates including one isolate resistant to trimethoprim/sulfamethoxazole (TMP/SMX) were tested. The inhibition zone sizes for the isolates ranged from 17 to 29 mm, while the MIC and MBC values ranged from 8 to 16  μg mL(-1) and 16 to 32  μg mL(-1). Chlorogenic acid appeared to be strongly bactericidal at 4x MIC, with a 2-log reduction in viable bacteria at 10 h. In vitro antibiofilm testing showed a 4-fold reduction in biofilm viability at 4x MIC compared to 1x MIC values (0.085 < 0.397 A 490 nm) of chlorogenic acid. The data from this study support the notion that the chlorogenic acid has promising in vitro antibacterial and antibiofilm activities against S. maltophilia.
    Matched MeSH terms: Stenotrophomonas maltophilia/drug effects*; Stenotrophomonas maltophilia/metabolism
  9. Fulltext Whole-Genome Sequence of Stenotrophomonas maltophilia ZBG7B Reveals Its Biotechnological Potential
    Chan KG, Chong TM, Adrian TG, Kher HL, Hong KW, Grandclément C, et al.
    Genome Announc, 2015;3(6).
    PMID: 26659682 DOI: 10.1128/genomeA.01442-15
    Stenotrophomonas maltophilia ZBG7B was isolated from vineyard soil of Zellenberg, France. Here, we present the draft genome sequence of this bacterial strain, which has facilitated the prediction of function for several genes encoding biotechnologically important enzymes, such as xylosidase, xylanase, laccase, and chitinase.
    Matched MeSH terms: Stenotrophomonas maltophilia
  10. Fulltext Stenotrophomonas maltophilia in Malaysia: molecular epidemiology and trimethoprim-sulfamethoxazole resistance
    Neela V, Rankouhi SZ, van Belkum A, Goering RV, Awang R
    Int J Infect Dis, 2012 Aug;16(8):e603-7.
    PMID: 22698885 DOI: 10.1016/j.ijid.2012.04.004
    Stenotrophomonas maltophilia is a recently identified nosocomial pathogen in Malaysia. Despite limited pathogenicity, its rate of isolation has increased in recent years. The aim of this study was to investigate the antibiotic susceptibility patterns, antibiotic resistance determinants, and the epidemiology of S. maltophilia at the largest tertiary care hospital in Malaysia.
    Matched MeSH terms: Stenotrophomonas maltophilia/drug effects*; Stenotrophomonas maltophilia/genetics*; Stenotrophomonas maltophilia/isolation & purification
  11. Fulltext Antibacterial and Antibiofilm Activities of Nonpolar Extracts of Allium stipitatum Regel. against Multidrug Resistant Bacteria
    Karunanidhi A, Ghaznavi-Rad E, Hamat RA, Pichika MR, Lung LTT, Mohd Fauzi F, et al.
    Biomed Res Int, 2018;2018:9845075.
    PMID: 30105271 DOI: 10.1155/2018/9845075
    The present study assessed the in vitro antibacterial and antibiofilm potential of hexane (ASHE) and dichloromethane (ASDE) extracts of Allium stipitatum (Persian shallot) against planktonic cells and biofilm structures of clinically significant antibiotic resistant pathogens, with a special emphasis on methicillin-sensitive Staphylococcus aureus (MSSA), methicillin-resistant S. aureus (MRSA), and emerging pathogens, Acinetobacter baumannii and Stenotrophomonas maltophilia. Antibacterial activities were determined through disk diffusion, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), time-kill kinetics, and electron microscopy. Antibiofilm activity was assessed by XTT [2,3-bis(2-methoxy-4-nitro-5-sulfo-phenyl)-2H-tetrazolium-5-carboxanilide] reduction assay and by confocal laser scanning microscopy (CLSM). The zone of inhibition ranged from 13 to 33 mm, while the MICs and MBCs ranged from 16 to 1024 μg mL-1. Both ASHE and ASDE completely eradicated overnight cultures of the test microorganisms, including antibiotic resistant strains. Time-kill studies showed that the extracts were strongly bactericidal against planktonic cultures of S. aureus, MRSA, Acinetobacter baumannii, and S. maltophilia as early as 4 hours postinoculation (hpi). ASHE and ASDE were shown to inhibit preformed biofilms of the four biofilm phenotypes tested. Our results demonstrate the potential therapeutic application of ASHE and ASDE to inhibit the growth of gram-positive and gram-negative biofilms of clinical significance and warrant further investigation of the potential of A. stipitatum bulbs against biofilm-related drug resistance.
    Matched MeSH terms: Stenotrophomonas maltophilia/drug effects
  12. Isolation and identification of biocellulose-producing bacterial strains from Malaysian acidic fruits
    Voon WW, Rukayadi Y, Meor Hussin AS
    Lett Appl Microbiol, 2016 May;62(5):428-33.
    PMID: 27002476 DOI: 10.1111/lam.12568
    Biocellulose (BC) is pure extracellular cellulose produced by several species of micro-organisms that has numerous applications in the food, biomedical and paper industries. However, the existing biocellulose-producing bacterial strain with high yield was limited. The aim of this study was to isolate and identify the potential biocellulose-producing bacterial isolates from Malaysian acidic fruits. One hundred and ninety-three bacterial isolates were obtained from 19 local acidic fruits collected in Malaysia and screened for their ability to produce BC. A total of 15 potential bacterial isolates were then cultured in standard Hestrin-Schramm (HS) medium statically at 30°C for 2 weeks to determine the BC production. The most potent bacterial isolates were identified using 16S rRNA gene sequence analysis, morphological and biochemical characteristics. Three new and potent biocellulose-producing bacterial strains were isolated from soursop fruit and identified as Stenotrophomonas maltophilia WAUPM42, Pantoea vagans WAUPM45 and Beijerinckia fluminensis WAUPM53. Stenotrophomonas maltophilia WAUPM42 was the most potent biocellulose-producing bacterial strain that produced the highest amount of BC 0·58 g l(-1) in standard HS medium. Whereas, the isolates P. vagans WAUPM45 and B. fluminensis WAUPM53 showed 0·50 and 0·52 g l(-1) of BC production, respectively.
    Matched MeSH terms: Stenotrophomonas maltophilia
  13. Fulltext Microbiota of Palm Oil Mill Wastewater in Malaysia
    Bala JD, Lalung J, Al-Gheethi AAS, Hossain K, Ismail N
    Trop Life Sci Res, 2018 Jul;29(2):131-163.
    PMID: 30112146 MyJurnal DOI: 10.21315/tlsr2018.29.2.10
    This study was aimed at identifying indigenous microorganisms from palm oil mill effluent (POME) and to ascertain the microbial load. Isolation and identification of indigenous microorganisms was subjected to standard microbiological methods and sequencing of the 16S rRNA and 18S rRNA genes. Sequencing of the 16S rRNA and 18S rRNA genes for the microbial strains signifies that they were known as Micrococcus luteus 101PB, Stenotrophomonas maltophilia 102PB, Bacillus cereus 103PB, Providencia vermicola 104PB, Klebsiella pneumoniae 105PB, Bacillus subtilis 106PB, Aspergillus fumigatus 107PF, Aspergillus nomius 108PF, Aspergillus niger 109PF and Meyerozyma guilliermondii 110PF. Results revealed that the population of total heterotrophic bacteria (THB) ranged from 9.5 × 105 - 7.9 × 106 cfu/mL. The total heterotrophic fungi (THF) ranged from 2.1 × 104 - 6.4 × 104 cfu/mL. Total viable heterotrophic indigenous microbial population on CMC agar ranged from 8.2 × 105 - 9.1 × 106 cfu/mL and 1.4 × 103 - 3.4 × 103 cfu/mL for bacteria and fungi respectively. The microbial population of oil degrading bacteria (ODB) ranged from 6.4 × 105 - 4.8 × 106 cfu/mL and the oil degrading fungi (ODF) ranged from 2.8 × 103 - 4.7 × 104 cfu/mL. The findings revealed that microorganisms flourish well in POME. Therefore, this denotes that isolating native microorganisms from POME is imperative for effectual bioremediation, biotreatment and biodegradation of industrial wastewaters.
    Matched MeSH terms: Stenotrophomonas maltophilia
  14. Fulltext A Combination of Trimethoprim-sulfamethoxazole and Ceftazidime Showed Good In Vitro Activity against Stenotrophomonas maltophilia
    Ismail N, Zam Z, Hassan SA, Rahman ZA
    Malays J Med Sci, 2017 Mar;24(2):21-27.
    PMID: 28894400 DOI: 10.21315/mjms2017.24.2.3
    BACKGROUND: Stenotrophomonas maltophilia has emerged as an important nosocomial pathogen, capable of causing a wide spectrum of infections. Treatment is difficult because it is resistant to many antimicrobial agents, thus reducing the treatment options. The aims of this study were to describe the antimicrobial susceptibility patterns and synergistic effect of selected antimicrobial combinations against S. maltophilia isolates.

    METHODS: This was a descriptive cross-sectional study undertaken in the Hospital Universiti Sains Malaysia from April 2011 to March 2012. S. maltophilia isolated from various clinical specimens were included in the study. Antimicrobial susceptibility testing was done using the epsilometer test (E-test) and interpreted according to the guidelines of the Clinical and Laboratory Standards Institute. In the synergy test, the isolates were tested against six different antimicrobial combinations.

    RESULTS: In total, 84 S. maltophilia isolates were collected and analysed. According to the E-test, the antimicrobial susceptibility of trimethoprim-sulfamethoxazole (TMP-SMX), tigecycline, and ciprofloxacin was 100%, 91.1%, and 88.9% respectively. The antimicrobial combination of TMP-SMX and ceftazidime showed the highest synergistic effect.

    CONCLUSION: TMP-SMX remains the antimicrobial of choice to treat S. maltophilia infection. TMP-SMX and ceftazidime was the most effective combination in vitro.

    Matched MeSH terms: Stenotrophomonas maltophilia
  15. Fulltext The antibacterial properties of Malaysian tualang honey against wound and enteric microorganisms in comparison to manuka honey
    Tan HT, Rahman RA, Gan SH, Halim AS, Hassan SA, Sulaiman SA, et al.
    BMC Complement Altern Med, 2009;9:34.
    PMID: 19754926 DOI: 10.1186/1472-6882-9-34
    Antibiotic resistance of bacteria is on the rise, thus the discovery of alternative therapeutic agents is urgently needed. Honey possesses therapeutic potential, including wound healing properties and antimicrobial activity. Although the antimicrobial activity of honey has been effectively established against an extensive spectrum of microorganisms, it differs depending on the type of honey. To date, no extensive studies of the antibacterial properties of tualang (Koompassia excelsa) honey on wound and enteric microorganisms have been conducted. The objectives of this study were to conduct such studies and to compare the antibacterial activity of tualang honey with that of manuka honey.
    Matched MeSH terms: Stenotrophomonas maltophilia/drug effects
  16. Fulltext The effect of dietary bacterial organic selenium on growth performance, antioxidant capacity, and Selenoproteins gene expression in broiler chickens
    Dalia AM, Loh TC, Sazili AQ, Jahromi MF, Samsudin AA
    BMC Vet Res, 2017 Aug 18;13(1):254.
    PMID: 28821244 DOI: 10.1186/s12917-017-1159-4
    BACKGROUND: Selenium (Se) is an essential trace mineral in broilers, which has several important roles in biological processes. Organic forms of Se are more efficient than inorganic forms and can be produced biologically via Se microbial reduction. Hence, the possibility of using Se-enriched bacteria as feed supplement may provide an interesting source of organic Se, and benefit broiler antioxidant system and other biological processes. The objective of this study was to examine the impacts of inorganic Se and different bacterial organic Se sources on the performance, serum and tissues Se status, antioxidant capacity, and liver mRNA expression of selenoproteins in broilers.

    RESULTS: Results indicated that different Se sources did not significantly (P ≤ 0.05) affect broiler growth performance. However, bacterial organic Se of T5 (basal diet +0.3 mg /kg feed ADS18 Se), T4 (basal diet +0.3 mg /kg feed ADS2 Se), and T3 (basal diet +0.3 mg /kg feed ADS1 Se) exhibited significantly (P ≤ 0.05) highest Se concentration in serum, liver, and kidney respectively. Dietary inorganic Se and bacterial organic Se were observed to significantly affect broiler serum ALT, AST, LDH activities and serum creatinine level. ADS18 supplemented Se of (Stenotrophomonas maltophilia) bacterial strain showed the highest GSH-Px activity with the lowest MDA content in serum, and the highest GSH-Px and catalase activity in the kidney, while bacterial Se of ADS2 (Klebsiella pneumoniae) resulted in a higher level of GSH-Px1 and catalase in liver. Moreover, our study showed that in comparison with sodium selenite, only ADS18 bacterial Se showed a significantly higher mRNA level in GSH-Px1, GSH-Px4, DIO1, and TXNDR1, while both ADS18 and ADS2 showed high level of mRNA of DIO2 compared to sodium selenite.

    CONCLUSIONS: The supplementation of bacterial organic Se in broiler chicken, improved tissue Se deposition, antioxidant status, and selenoproteins gene expression, and can be considered as an effective alternative source of Se in broiler chickens.

    Matched MeSH terms: Stenotrophomonas maltophilia/metabolism
  17. Fulltext Effect of Sodium Selenite, Selenium Yeast, and Bacterial Enriched Protein on Chicken Egg Yolk Color, Antioxidant Profiles, and Oxidative Stability
    Muhammad AI, Mohamed DAA, Chwen LT, Akit H, Samsudin AA
    Foods, 2021 Apr 16;10(4).
    PMID: 33923439 DOI: 10.3390/foods10040871
    The chicken egg is one of nature's flawlessly preserved biological products, recognized as an excellent source of nutrients for humans. Selenium (Se) is an essential micro-element that plays a key role in biological processes. Organic selenium can be produced biologically by the microbial reduction of inorganic Se (sodium selenite). Therefore, the possibility of integrating Se enriched bacteria as a supplement in poultry feed can provide an interesting source of organic Se, thereby offering health-related advantages to humans. In this study, bacterial selenoproteins from Stenotrophomonas maltophilia was used as a dietary supplement with other Se sources in Lohman brown Classic laying hens to study the egg yolk color, egg yolk and breast antioxidant profile, oxidative stability, and storage effect for fresh and stored egg yolk at 4 ± 2 °C for 14-days. The results showed that dietary Se supplementation significantly (p < 0.05) improved egg yolk color, the antioxidant profile of egg yolk, and breast meat (total carotenoid and phenol content). When the Se treated groups were compared to control groups, there was a significant (p < 0.05) decrease in total cholesterol in fresh and stored egg yolk and breast muscle. In hens that were fed ADS18-Se, the primary oxidation products (MDA) concentrations in the eggs, breast, and thigh muscle, and plasma were significantly (p < 0.05) lower. However, the MDA content increased (p < 0.05) with an extended storage time in egg yolk. In comparison to inorganic Se and basal diets, egg yolk from hens fed organic Se remained fresh for two weeks. The egg yolk color, antioxidant profile, and oxidative status of egg yolk and tissue improve with dietary Se organic supplementation (ADS18 > Se-Yeast). The source of supplemented organic Se is critical for egg enrichment and antioxidant properties. As a result, ''functional eggs'' enriched with organic Se becomes possible to produce.
    Matched MeSH terms: Stenotrophomonas maltophilia
  18. Fulltext High Genetic Diversity among Stenotrophomonas maltophilia Isolates from Single Hospital: Nosocomial Outbreaks or Genotypic Profile Changes during Subcultures
    Güvenir M, Otlu B, Tunc E, Aktas E, Suer K
    Malays J Med Sci, 2018 Mar;25(2):40-49.
    PMID: 30918454 DOI: 10.21315/mjms2018.25.2.5
    Background: Stenotrophomonas maltophilia is a non-fermentative gram-negative bacillus which is widely recognised as an important nosocomial pathogen causing pneumonia, blood-stream, wound and urinary tract infections, particularly in immunosuppressed patients. The aim of this study was to evaluate a nosocomial outbreak of by S. maltophilia in an intensive care unit of a tertiary hospital and evaluate unexpected multiclonality.

    Methods: A total of 11 isolates from respiratory cultures in intensive care unit of a 24 bed tertiary hospital obtained over a one months period and one isolate obtained from the nebuliser during environmental screening were investigated. The bacteria were identified by Phoenix 100 system. The clonal relatedness was evaluated by PFGE and semi-automated repetitive sequence-based PCR. Genotyping tests were repeated for 10 serial subcultures.

    Results: PFGE and DiversiLab yielded 10 genotypic profiles for 12 isolates. Four to eight different genotypes were observed from 10 subcultures of the same isolate.

    Conclusion: We conclude that, high genetic diversity and supposed multiclonal appearance of the outbreak isolates may be due to changing profiles during subcultures most probably depending on hypermutation.

    Matched MeSH terms: Stenotrophomonas maltophilia
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