Displaying publications 21 - 40 of 935 in total

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  1. Boey KPY, Zhu P, Tan H, Abdullah MAB, Tang KF, Li MM, et al.
    Transfus Med, 2022 Feb;32(1):82-87.
    PMID: 34862686 DOI: 10.1111/tme.12834
    OBJECTIVE: To evaluate the effects of cryopreservation in post-thaw umbilical cord blood units for the survivability of Gram-positive bacteria strains.

    BACKGROUND: Microbial screening is required for all cord blood units (CBUs). Four gram-positive contaminants were documented to survive cryopreservation poorly and isolation of other contaminants were reported.

    METHODS: Forty-eight contaminated CBUs detected with either Staphylococcus epidermidis, Corynebacterium species, Peptostreptococcus or Streptococcus species before cryopreservation were used in this study. CBUs were processed, DMSO-infused and microbial screened before cryopreservation. Post-thaw microbial screening was achieved using 1 and 10 ml inoculants in BACTEC culture bottles. Positive bottles were subjected for microbial identification and results were compared with those from pre-freeze.

    RESULTS: A higher rate of microbial contamination was found using the 10 ml inoculant. Screening of 11 CBUs did not detect any contaminants while 30 CBUs screened detected more than one unknown contaminants and majority of contaminants were identified to be gram-negative species.

    CONCLUSION: A higher inoculation volume used at post-thaw for microbial screening improves contamination detection but leads to the loss of precious cord blood. Some contaminants did not survive cryopreservation or were not identified due to their low microbial levels. Contrasting contaminants found at post-thaw suggest the improvements made in detection and identification of contaminants over the years.

    Matched MeSH terms: Gram-Positive Bacteria*
  2. Tay ST, Merican AM, Abdul Jabar K, Velayuthan RD, Ayob KA, Lee JL, et al.
    Int J Infect Dis, 2023 Nov;136:77-80.
    PMID: 37660726 DOI: 10.1016/j.ijid.2023.08.025
    We report the isolation of a rare Gram-positive coccobacillary bacterium from synovial fluids of a patient with periprosthetic joint infection on three occasions over an 8-month period. As routine microbiological methods were not able to identify the isolate definitely, sequence analyses of the bacterial 16S ribosomal RNA gene and whole genome were performed. Analysis of the bacterial 16S ribosomal RNA gene showed the highest similarity (98.1%) with that of Falsarthrobacter (previously known as Arthrobacter) nasiphocae, which was first isolated from the nasal cavities of common seals (Phoca vitulina). The genome size of the strain (designated as UM1) is 2.4 Mb. With a high G+C content (70.4 mol%), strain UM1 is phylogenetically most closely related to F. nasiphocae based on whole genome analysis. Strain UM1 was susceptible to vancomycin, linezolid, trimethoprim-sulfamethoxazole, doxycycline, and intermediate to penicillin and ciprofloxacin. Ceftriaxone resistance was noted. The patient who was also on hemodialysis for his end stage kidney disease died approximately 3 weeks following implant removal and fusion with an external fixator. This study describes the first isolation of F. nasiphocae from human clinical samples. The use of emerging technologies has supported more definitive etiological diagnosis associated with rarely encountered organisms in periprosthetic joint infection.
    Matched MeSH terms: Bacteria; Gram-Positive Bacteria
  3. Chuah LF, Nawaz A, Dailin DJ, Oloruntobi O, Habila MA, Tong WY, et al.
    Chemosphere, 2023 Oct;337:139293.
    PMID: 37369285 DOI: 10.1016/j.chemosphere.2023.139293
    Crude oil pollution is one of the most serious environmental issues today, and the clean-up procedure is perhaps the most difficult. Within one to three weeks, the vast majority of oil bacteria may degrade approximately 60% of the crude oil, leaving approximately 40% intact. The by-product metabolites produced during the breakdown of oil are essentially organic molecules in nature. These metabolites inhibit its enzymes, preventing the oil bacteria from further degrading the oil. By combining a variety of different oils with heterotrophic bacteria in a bioreactor, the rate of crude oil biodegradation was accelerated. In this study, two strains of oil-resistant, heterotrophic bacteria (OG1 and OG2-Erythrobacter citreus) and a bacterium that uses hydrocarbons (AR3-Pseudomonas pseudoalcaligenes) were used. Gas chromatography-mass spectroscopy was used to investigate the effectiveness of this consortium of symbiotic bacteria in the biodegradation of crude oil. According to gravimetric and gas chromatography analyses, the consortium bacteria digested 69.6% of the crude oil in the bioreactor, while the AR3 single strain was only able to destroy 61.9% of it. Under the same experimental conditions, consortium bacteria degraded approximately 84550.851 ppb (96.3%) of 16 aliphatic hydrocarbons and 9333.178 ppb (70.5%) of 16 aromatic hydrocarbons in the bioreactor. It may be inferred that the novel consortium of symbiotic bacteria accelerated the biodegradation process and had great potential for use in increasing the bioremediation of hydrocarbon-contaminated locations.
    Matched MeSH terms: Bacteria/metabolism
  4. Lee WX, Basri DF, Ghazali AR
    Molecules, 2017 Mar 17;22(3).
    PMID: 28304328 DOI: 10.3390/molecules22030463
    The antibacterial activity of pterostilbene in combination with gentamicin against six strains of Gram-positive and Gram-negative bacteria were investigated. The minimum inhibitory concentration and minimum bactericidal concentration of pterostilbene were determined using microdilution technique whereas the synergistic antibacterial activities of pterostilbene in combination with gentamicin were assessed using checkerboard assay and time-kill kinetic study. Results of the present study showed that the combination effects of pterostilbene with gentamicin were synergistic (FIC index < 0.5) against three susceptible bacteria strains: Staphylococcus aureus ATCC 25923, Escherichia coli O157 and Pseudomonas aeruginosa 15442. However, the time-kill study showed that the interaction was indifference which did not significantly differ from the gentamicin treatment. Furthermore, time-kill study showed that the growth of the tested bacteria was completely attenuated with 2 to 8 h treatment with 0.5 × MIC of pterostilbene and gentamicin. The identified combinations could be of effective therapeutic value against bacterial infections. These findings have potential implications in delaying the development of bacterial resistance as the antibacterial effect was achieved with the lower concentrations of antibacterial agents.
    Matched MeSH terms: Anti-Bacterial Agents/pharmacology*; Anti-Bacterial Agents/chemistry; Bacteria/drug effects*; Bacteria/ultrastructure; Gram-Negative Bacteria/drug effects; Gram-Negative Bacteria/ultrastructure; Gram-Positive Bacteria/drug effects; Gram-Positive Bacteria/ultrastructure
  5. Carrión O, Gibson L, Elias DMO, McNamara NP, van Alen TA, Op den Camp HJM, et al.
    Microbiome, 2020 06 03;8(1):81.
    PMID: 32493439 DOI: 10.1186/s40168-020-00860-7
    BACKGROUND: Isoprene is the most abundantly produced biogenic volatile organic compound (BVOC) on Earth, with annual global emissions almost equal to those of methane. Despite its importance in atmospheric chemistry and climate, little is known about the biological degradation of isoprene in the environment. The largest source of isoprene is terrestrial plants, and oil palms, the cultivation of which is expanding rapidly, are among the highest isoprene-producing trees.

    RESULTS: DNA stable isotope probing (DNA-SIP) to study the microbial isoprene-degrading community associated with oil palm trees revealed novel genera of isoprene-utilising bacteria including Novosphingobium, Pelomonas, Rhodoblastus, Sphingomonas and Zoogloea in both oil palm soils and on leaves. Amplicon sequencing of isoA genes, which encode the α-subunit of the isoprene monooxygenase (IsoMO), a key enzyme in isoprene metabolism, confirmed that oil palm trees harbour a novel diversity of isoA sequences. In addition, metagenome-assembled genomes (MAGs) were reconstructed from oil palm soil and leaf metagenomes and putative isoprene degradation genes were identified. Analysis of unenriched metagenomes showed that isoA-containing bacteria are more abundant in soils than in the oil palm phyllosphere.

    CONCLUSION: This study greatly expands the known diversity of bacteria that can metabolise isoprene and contributes to a better understanding of the biological degradation of this important but neglected climate-active gas. Video abstract.

    Matched MeSH terms: Bacteria/classification; Bacteria/metabolism
  6. Rahman RNZRA, Latip W, Adlan NA, Sabri S, Ali MSM
    Arch Microbiol, 2022 Nov 12;204(12):701.
    PMID: 36370212 DOI: 10.1007/s00203-022-03316-8
    Waxy crude oil is a problem to the oil and gas industry because wax deposition in pipelines reduces the quality of the crude oil. Currently, the industry uses chemicals to solve the problem but it is not environmentally friendly. As an alternative, the biodegradation approach is one of the options. Previously eleven thermophilic bacteria were isolated and exhibited high ability to degrade hydrocarbon up to 70% of waxy crude oil. However, despite the successful study on these single bacteria strains, it is believed that biodegradation of paraffin wax requires more than a single species. Five consortia were developed based on the biodegradation efficiency of 11 bacterial strains. Consortium 3 showed the highest biodegradation (77.77%) with more long-chain alkane degraded throughout the incubation compared to other consortia. Enhancement of hydrocarbon degradation was observed for all consortia especially in long chain alkane (C18-C40). Consortium 3 exhibited higher alkane monooxygenase, alcohol dehydrogenase, lipase, and esterase activities. Moreover, the dominant bacteria in the consortia were determined by denaturing gradient gel electrophoresis (DGGE), which showed the domination of genera Geobacillus, Parageobacillus, and Anoxybacillus. It can be concluded that the bacterial consortia showed higher biodegradation and improved degrading more long-chain hydrocarbon compared to a single isolate.
    Matched MeSH terms: Bacteria/genetics; Bacteria/metabolism
  7. Chan WT, Garcillán-Barcia MP, Yeo CC, Espinosa M
    FEMS Microbiol Rev, 2023 Sep 05;47(5).
    PMID: 37715317 DOI: 10.1093/femsre/fuad052
    Toxin-antitoxin (TA) systems are entities found in the prokaryotic genomes, with eight reported types. Type II, the best characterized, is comprised of two genes organized as an operon. Whereas toxins impair growth, the cognate antitoxin neutralizes its activity. TAs appeared to be involved in plasmid maintenance, persistence, virulence, and defence against bacteriophages. Most Type II toxins target the bacterial translational machinery. They seem to be antecessors of Higher Eukaryotes and Prokaryotes Nucleotide-binding (HEPN) RNases, minimal nucleotidyltransferase domains, or CRISPR-Cas systems. A total of four TAs encoded by Streptococcus pneumoniae, RelBE, YefMYoeB, Phd-Doc, and HicAB, belong to HEPN-RNases. The fifth is represented by PezAT/Epsilon-Zeta. PezT/Zeta toxins phosphorylate the peptidoglycan precursors, thereby blocking cell wall synthesis. We explore the body of knowledge (facts) and hypotheses procured for Type II TAs and analyse the data accumulated on the PezAT family. Bioinformatics analyses showed that homologues of PezT/Zeta toxin are abundantly distributed among 14 bacterial phyla mostly in Proteobacteria (48%), Firmicutes (27%), and Actinobacteria (18%), showing the widespread distribution of this TA. The pezAT locus was found to be mainly chromosomally encoded whereas its homologue, the tripartite omega-epsilon-zeta locus, was found mostly on plasmids. We found several orphan pezT/zeta toxins, unaccompanied by a cognate antitoxin.
    Matched MeSH terms: Bacteria/genetics; Bacteria/metabolism; Bacterial Proteins/genetics; Bacterial Proteins/metabolism
  8. Chan KG, Yin WF, Lim YL
    Genome Announc, 2014;2(2).
    PMID: 24699957 DOI: 10.1128/genomeA.00246-14
    Here, we report the complete genome sequence of Pseudomonas aeruginosa strain YL84, which was isolated from compost. This strain was found to be a chitinase-producing quorum-sensing bacterium.
    Matched MeSH terms: Bacteria
  9. Gan HY, Gan HM, Savka MA, Triassi AJ, Wheatley MS, Smart LB, et al.
    Genome Announc, 2014;2(3).
    PMID: 24812212 DOI: 10.1128/genomeA.00288-14
    Shrub willow, Salix spp. and hybrids, is an important bioenergy crop. Here we report the whole-genome sequences and annotation of 13 endophytic bacteria from stem tissues of Salix purpurea grown in nature and from commercial cultivars and Salix viminalis × Salix miyabeana grown in bioenergy fields in Geneva, New York.
    Matched MeSH terms: Bacteria
  10. Chan XY, Hong KW, Yin WF, Chan KG
    Sci Rep, 2016 Jan 28;6:20016.
    PMID: 26817720 DOI: 10.1038/srep20016
    Tropical carnivorous plant, Nepenthes, locally known as "monkey cup", utilises its pitcher as a passive trap to capture insects. It then secretes enzymes into the pitcher fluid to digest the insects for nutrients acquisition. However, little is known about the microbiota and their activity in its pitcher fluid. Eighteen bacteria phyla were detected from the metagenome study in the Nepenthes pitcher fluid. Proteobacteria, Bacteroidetes and Actinobacteria are the dominant phyla in the Nepenthes pitcher fluid. We also performed culturomics approach by isolating 18 bacteria from the Nepenthes pitcher fluid. Most of the bacterial isolates possess chitinolytic, proteolytic, amylolytic, and cellulolytic and xylanolytic activities. Fifteen putative chitinase genes were identified from the whole genome analysis on the genomes of the 18 bacteria isolated from Nepenthes pitcher fluid and expressed for chitinase assay. Of these, six clones possessed chitinase activity. In conclusion, our metagenome result shows that the Nepenthes pitcher fluid contains vast bacterial diversity and the culturomic studies confirmed the presence of biocatalytic bacteria within the Nepenthes pitcher juice which may act in symbiosis for the turn over of insects trapped in the Nepenthes pitcher fluid.
    Matched MeSH terms: Bacteria/classification; Bacteria/genetics; Bacteria/metabolism; Genome, Bacterial
  11. Yong D, Ee R, Lim YL, Chang CY, Yin WF, Chan KG
    Genome Announc, 2015;3(3).
    PMID: 25953192 DOI: 10.1128/genomeA.00409-15
    Lysinibacillus fusiformis strain RB21 is a quorum-quenching bacterium that is able to degrade quorum-sensing signaling molecules. Here, we present the first complete genome sequence of L. fusiformis strain RB21. The finished genome is 4.8 Mbp in size, and the quorum-quenching gene was identified.
    Matched MeSH terms: Bacteria
  12. Mohd Nadzir M, Nurhayati RW, Idris FN, Nguyen MH
    Polymers (Basel), 2021 Feb 10;13(4).
    PMID: 33578978 DOI: 10.3390/polym13040530
    Bacterial exopolysaccharides (EPSs) are an essential group of compounds secreted by bacteria. These versatile EPSs are utilized individually or in combination with different materials for a broad range of biomedical field functions. The various applications can be explained by the vast number of derivatives with useful properties that can be controlled. This review offers insight on the current research trend of nine commonly used EPSs, their biosynthesis pathways, their characteristics, and the biomedical applications of these relevant bioproducts.
    Matched MeSH terms: Bacteria
  13. Kim M, Singh D, Lai-Hoe A, Go R, Abdul Rahim R, Ainuddin AN, et al.
    Microb Ecol, 2012 Apr;63(3):674-81.
    PMID: 21990015 DOI: 10.1007/s00248-011-9953-1
    Recent work has suggested that in temperate and subtropical trees, leaf surface bacterial communities are distinctive to each individual tree species and dominated by Alpha- and Gammaproteobacteria. In order to understand how general this pattern is, we studied the phyllosphere bacterial community on leaves of six species of tropical trees at a rainforest arboretum in Malaysia. This represents the first detailed study of 'true' tropical lowland tree phyllosphere communities. Leaf surface DNA was extracted and pyrosequenced targeting the V1-V3 region of 16S rRNA gene. As was previously found in temperate and subtropical trees, each tree species had a distinctive bacterial community on its leaves, clustering separately from other tree species in an ordination analysis. Bacterial communities in the phyllosphere were unique to plant leaves in that very few operational taxonomic units (0.5%) co-occurred in the surrounding soil environment. A novel and distinctive aspect of tropical phyllosphere communities is that Acidobacteria were one of the most abundant phyla across all samples (on average, 17%), a pattern not previously recognized. Sequences belonging to Acidobacteria were classified into subgroups 1-6 among known 24 subdivisions, and subgroup 1 (84%) was the most abundant group, followed by subgroup 3 (15%). The high abundance of Acidobacteria on leaves of tropical trees indicates that there is a strong relationship between host plants and Acidobacteria in tropical rain forest, which needs to be investigated further. The similarity of phyllosphere bacterial communities amongst the tree species sampled shows a significant tendency to follow host plant phylogeny, with more similar communities on more closely related hosts.
    Matched MeSH terms: Bacteria/classification; Bacteria/genetics; Bacteria/isolation & purification*
  14. Tin HS, Palaniveloo K, Anilik J, Vickneswaran M, Tashiro Y, Vairappan CS, et al.
    Microb Ecol, 2018 Feb;75(2):459-467.
    PMID: 28779295 DOI: 10.1007/s00248-017-1043-6
    Decline in forest productivity due to forest conversion is defining the Bornean landscape. Responses of bacterial communities due to land-use changes are vital and could define our understanding of ecosystem functions. This study reports the changes in bacterial community structure in organic soil (0-5 cm; O-Horizon) and organic-mineral soil (5-15 cm; A-Horizon) across Maliau Basin Conservation Area old growth forest (MBOG), Fragment E logged forest (FELF) located in Kalabakan Forest Reserve to Benta Wawasan oil palm plantation (BWOP) using two-step PCR amplicon analysis of bacteria DNA on Illumina Miseq next generation sequencing. A total of 30 soil samples yielded 893,752-OTU reads at ≥97% similarity from 5,446,512 good quality sequences. Soil from BWOP plantation showed highest unshared OTUs for organic (49.2%) and organic-mineral (50.9%) soil. MBOG soil showed a drop in unshared OTUs between organic (48.6%) and organic-mineral (33.9%). At phylum level, Proteobacteria dominated MBOG but shifted to Actinobacteria in logged and plantation soil. Present findings also indicated that only FELF exhibited change in bacterial communities along the soil depth, moving from the organic to the organic-mineral layer. Both layers of BWOP plantation soils deviated from other forests' soil in β-diversity analysis. To our knowledge, this is the first report on transitions of bacterial community structures with different soil horizons in the tropical rainforest including Borneo, Sabah. Borneo tropical soils form a large reservoir for soil bacteria and future exploration is needed for fully understanding the diversity structure and their bacterial functional properties.
    Matched MeSH terms: Bacteria/classification; Bacteria/genetics; Bacteria/isolation & purification*
  15. Liew KJ, Teo SC, Shamsir MS, Goh KM
    Microbiol Resour Announc, 2019 Nov 14;8(46).
    PMID: 31727717 DOI: 10.1128/MRA.01238-19
    Longimonas halophila and Longibacter salinarum are type strains of underexplored genera affiliated with Salisaetaceae Herein, we report the draft genome sequences of two strains of these bacteria, L. halophila KCTC 42399 and L. salinarum KCTC 52045, with the intent of broadening knowledge of this family. Genome annotation and gene mining revealed that both bacteria exhibit amylolytic abilities.
    Matched MeSH terms: Bacteria
  16. Lim YL, Ee R, Yong D, Tee KK, Yin WF, Chan KG
    J Biotechnol, 2015 Nov 20;214:83-4.
    PMID: 26393955 DOI: 10.1016/j.jbiotec.2015.09.018
    Pandoraea pnomenusa RB-38 is a bacterium isolated from a former sanitary landfill site. Here, we present the complete genome of P. pnomenusa RB38 in which an oxalate utilization pathway was identified. The genome analysis suggested the potential of this strain as an effective biocontrol agent against oxalate-producing phytopathogens.
    Matched MeSH terms: Bacteria
  17. Chukwuma OB, Rafatullah M, Tajarudin HA, Ismail N
    PMID: 34204975 DOI: 10.3390/ijerph18116001
    Discovering novel bacterial strains might be the link to unlocking the value in lignocellulosic bio-refinery as we strive to find alternative and cleaner sources of energy. Bacteria display promise in lignocellulolytic breakdown because of their innate ability to adapt and grow under both optimum and extreme conditions. This versatility of bacterial strains is being harnessed, with qualities like adapting to various temperature, aero tolerance, and nutrient availability driving the use of bacteria in bio-refinery studies. Their flexible nature holds exciting promise in biotechnology, but despite recent pointers to a greener edge in the pretreatment of lignocellulose biomass and lignocellulose-driven bioconversion to value-added products, the cost of adoption and subsequent scaling up industrially still pose challenges to their adoption. However, recent studies have seen the use of co-culture, co-digestion, and bioengineering to overcome identified setbacks to using bacterial strains to breakdown lignocellulose into its major polymers and then to useful products ranging from ethanol, enzymes, biodiesel, bioflocculants, and many others. In this review, research on bacteria involved in lignocellulose breakdown is reviewed and summarized to provide background for further research. Future perspectives are explored as bacteria have a role to play in the adoption of greener energy alternatives using lignocellulosic biomass.
    Matched MeSH terms: Bacteria
  18. Sam KK, Lau NS, Furusawa G, Amirul AA
    Genome Announc, 2017 Oct 19;5(42).
    PMID: 29051257 DOI: 10.1128/genomeA.01147-17
    Hahella sp. strain CCB-MM4 is a halophilic bacterium isolated from estuarine mangrove sediment. The genome sequence of Hahella sp. CCB-MM4 provides insights into exopolysaccharide biosynthesis and the lifestyle of the bacterium thriving in a saline mangrove environment.
    Matched MeSH terms: Bacteria; Gammaproteobacteria
  19. Firdose A, Chong NHH, Ramli R, Aqma WS
    Lett Appl Microbiol, 2023 Feb 16;76(2).
    PMID: 36702549 DOI: 10.1093/lambio/ovad013
    The aim of this study was to test the antimicrobial, antiadhesive, and antibiofilm activities of a rhamnolipid extracted from Pseudomonas aeruginosa UKMP14T previously isolated from oil-contaminated soil in Malaysia against ESKAPE (i.e. multidrug resistant) pathogens. Zones of inhibition in an agar well diffusion assay were observed at 50 µg mL-1 concentrations of rhamnolipid for all the ESKAPE bacteria. The MIC and MBC values ranged between 7.81-62.5 µg mL-1 and 31.25-1000 µg mL-1, respectively. Percent killing was recorded to be >90% except for Klebsiella pneumoniae (86.84%). Furthermore, antiadhesion studies showed that there was 76% hindrance in attachment of Enterococcus faecium and 91% in Acinetobacter baumannii at 4 × MIC. The highest inhibition in adhesion was found at 4 × MIC, which was 46% for Ac. baumannii and 62% for Enterococcus faecium. Finally, the antibiofilm capability of the rhamnolipid was determined, which ranged between 25%-76% in Ac. baumannii and 35%-88% in Enterococcus faecium. To the best of our knowledge, this is the first study to include research on antimicrobial, antiadhesive and antibiofilm activities of rhamnolipid from the local isolate Ps. aeruginosa UKMP14T against ESKAPE bacteria. Obtained results suggest that this rhamnolipid can be exploited commercially for the production of novel antibiotics.
    Matched MeSH terms: Bacteria
  20. Tobuse AJ, Ang CW, Yeong KY
    Life Sci, 2022 Aug 01;302:120660.
    PMID: 35642852 DOI: 10.1016/j.lfs.2022.120660
    With the continuous evolution of bacteria, the global antimicrobial resistance health threat is causing millions of deaths yearly. While depending on antibiotics as a primary treatment has its merits, there are no effective alternatives thus far in the pharmaceutical market against some drug-resistant bacteria. In recent years, vaccinology has become a key topic in scientific research. Combining with the growth of technology, vaccine research is seeing a new light where the process is made faster and more efficient. Although less discussed, bacterial vaccine is a feasible strategy to combat antimicrobial resistance. Some vaccines have shown promising results with good efficacy against numerous multidrug-resistant strains of bacteria. In this review, we aim to discuss the findings from studies utilizing reverse vaccinology for vaccine development against some multidrug-resistant bacteria, as well as provide a summary of multi-year bacterial vaccine studies in clinical trials. The advantages of reverse vaccinology in the generation of new bacterial vaccines are also highlighted. Meanwhile, the limitations and future prospects of bacterial vaccine concludes this review.
    Matched MeSH terms: Bacteria; Bacterial Vaccines; Drug Resistance, Bacterial
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