Displaying publications 161 - 180 of 928 in total

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  1. Fulltext Bacterial and fungal keratitis in Upper Egypt: in vitro screening of enzymes, toxins and antifungal activity
    Gharamah AA, Moharram AM, Ismail MA, Al-Hussaini AK
    Indian J Ophthalmol, 2014 Feb;62(2):196-203.
    PMID: 24008795 DOI: 10.4103/0301-4738.116463
    This work was conducted to study the ability of bacterial and fungal isolates from keratitis cases in Upper Egypt to produce enzymes, toxins, and to test the isolated fungal species sensitivity to some therapeutic agents.
    Matched MeSH terms: Anti-Bacterial Agents/therapeutic use*; Bacteria/drug effects; Bacteria/isolation & purification; Bacteria/metabolism; Bacterial Toxins/metabolism*; Eye Infections, Bacterial/drug therapy; Eye Infections, Bacterial/microbiology; Eye Infections, Bacterial/epidemiology*
  2. Fulltext Bacterial communities associated with silage of different forage crops in Malaysian climate analysed using 16S amplicon metagenomics
    Hisham MB, Hashim AM, Mohd Hanafi N, Abdul Rahman N, Abdul Mutalib NE, Tan CK, et al.
    Sci Rep, 2022 May 02;12(1):7107.
    PMID: 35501317 DOI: 10.1038/s41598-022-08819-4
    Silage produced in tropical countries is prone to spoilage because of high humidity and temperature. Therefore, determining indigenous bacteria as potential inoculants is important to improve silage quality. This study aimed to determine bacterial community and functional changes associated with ensiling using amplicon metagenomics and to predict potential bacterial additives associated with silage quality in the Malaysian climate. Silages of two forage crops (sweet corn and Napier) were prepared, and their fermentation properties and functional bacterial communities were analysed. After ensiling, both silages were predominated by lactic acid bacteria (LAB), and they exhibited good silage quality with significant increment in lactic acid, reductions in pH and water-soluble carbohydrates, low level of acetic acid and the absence of propionic and butyric acid. LAB consortia consisting of homolactic and heterolactic species were proposed to be the potential bacterial additives for sweet corn and Napier silage fermentation. Tax4fun functional prediction revealed metabolic pathways related to fermentation activities (bacterial division, carbohydrate transport and catabolism, and secondary metabolite production) were enriched in ensiled crops (p 
    Matched MeSH terms: Bacteria
  3. Bacterial communities associated with the pitcher fluids of three Nepenthes (Nepenthaceae) pitcher plant species growing in the wild
    Chou LY, Clarke CM, Dykes GA
    Arch Microbiol, 2014 Oct;196(10):709-17.
    PMID: 25005571 DOI: 10.1007/s00203-014-1011-1
    Nepenthes pitcher plants produce modified jug-shaped leaves to attract, trap and digest insect prey. We used 16S rDNA cloning and sequencing to compare bacterial communities in pitcher fluids of each of three species, namely Nepenthes ampullaria, Nepenthes gracilis and Nepenthes mirabilis, growing in the wild. In contrast to previous greenhouse-based studies, we found that both opened and unopened pitchers harbored bacterial DNA. Pitchers of N. mirabilis had higher bacterial diversity as compared to other Nepenthes species. The composition of the bacterial communities could be different between pitcher types for N. mirabilis (ANOSIM: R = 0.340, p < 0.05). Other Nepenthes species had similar bacterial composition between pitcher types. SIMPER showed that more than 50 % of the bacterial taxa identified from the open pitchers of N. mirabilis were not found in other groups. Our study suggests that bacteria in N. mirabilis are divided into native and nonnative groups.
    Matched MeSH terms: Bacteria/classification; Bacteria/genetics; Bacteria/isolation & purification*
  4. Bacterial communities in Haemaphysalis, Dermacentor and Amblyomma ticks collected from wild boar of an Orang Asli Community in Malaysia
    Lim FS, Khoo JJ, Tan KK, Zainal N, Loong SK, Khor CS, et al.
    Ticks Tick Borne Dis, 2020 03;11(2):101352.
    PMID: 31866439 DOI: 10.1016/j.ttbdis.2019.101352
    Ticks are hematophagous vectors of arthropod-borne disease agents globally. In Malaysia, despite seroprevalence studies indicating the presence of tick-borne diseases among the indigenous people, the etiological agents of these diseases are still unclear. These indigenous people, also known as the Orang Asli, still live in forested areas with frequent contact with wildlife. Wild boar are ubiquitously found in the forested areas where the Orang Asli communities are located and are commonly hunted as a food supplement. In this study, we aim to determine the tick species parasitizing wild boar from an Orang Asli community, and explore the tick-associated bacterial communities using 16 s rRNA amplicon sequencing on the Ion Torrent PGM™ platform. A total of 72 ticks were collected from three wild boar and were morphologically identified as Haemaphysalis hystricis (n = 32), Dermacentor compactus (n = 15), Amblyomma testudinarium (n = 13), Dermacentor steini (n = 10) and Dermacentor atrosignatus (n = 2). Across all tick samples, 910 bacterial taxa were identified. Although the bacterial communities were not significantly distinct between tick species in beta-diversity analyses, Coxiella, Rickettsia and Francisella were detected at high relative abundance in H. hystricis, D. compactus and D. steini respectively. Many other bacterial genera, including those that have been described in many different tick species, were also identified, including Pseudomonas, Acinetobacter, Staphylococcus and Corynebacterium. Beta-diversity analyses also showed that the bacterial communities were separated based on the animal host from which the ticks were collected from, suggesting that the bacterial communities here may be influenced by the animal skin microflora, host blood or the environment. PCR screening confirmed the presence of Rickettsia sp. related to spotted fever group Rickettsia in some of the ticks. This study provides baseline knowledge of the microbiome of H. hystricis, D. atrosignatus, D. compactus, D. steini and A. testudinarium parasitizing wild boar in this region. The information gained in this study provides the basis to target our efforts in H. hystricis, D. compactus and D. steini for the future investigation of vector competence and the zoonotic potential for the Coxiella, Rickettsia and Francisella detected here, as well as their implications for the risks of tick-borne diseases among the Orang Asli communities.
    Matched MeSH terms: Bacteria/classification; Bacteria/isolation & purification*; Bacterial Infections/microbiology; Bacterial Infections/epidemiology; Bacterial Infections/veterinary*; RNA, Bacterial/analysis
  5. Bacterial community diversity in the rhizosphere of nickel hyperaccumulator plant species from Borneo Island (Malaysia)
    Lopez S, van der Ent A, Sumail S, Sugau JB, Buang MM, Amin Z, et al.
    Environ Microbiol, 2020 04;22(4):1649-1665.
    PMID: 32128926 DOI: 10.1111/1462-2920.14970
    The Island of Borneo is a major biodiversity hotspot, and in the Malaysian state of Sabah, ultramafic soils are extensive and home to more than 31 endemic nickel hyperaccumulator plants. The aim of this study was to characterize the structure and the diversity of the rhizosphere bacterial communities of several of these nickel hyperaccumulator plants and factors that affect these bacterial communities in Sabah. The most abundant phyla were Proteobacteria, Acidobacteria and Actinobacteria. At family level, Burkholderiaceae and Xanthobacteraceae (Proteobacteria phylum) were the most abundant families in the hyperaccumulator rhizospheres. Redundancy analysis based on soil chemical analyses and relative abundances of the major bacterial phyla showed that abiotic factors of the studied sites drove the bacterial diversity. For all R. aff. bengalensis rhizosphere soil samples, irrespective of studied site, the bacterial diversity was similar. Moreover, the Saprospiraceae family showed a high representativeness in the R. aff. bengalensis rhizosphere soils and was linked with the nickel availability in soils. The ability of R. aff. bengalensis to concentrate nickel in its rhizosphere appears to be the major factor driving the rhizobacterial community diversity unlike for other hyperaccumulator species.
    Matched MeSH terms: Bacteria; Proteobacteria; Actinobacteria; Acidobacteria
  6. Fulltext Bacterial community in Haemaphysalis ticks of domesticated animals from the Orang Asli communities in Malaysia
    Khoo JJ, Chen F, Kho KL, Ahmad Shanizza AI, Lim FS, Tan KK, et al.
    Ticks Tick Borne Dis, 2016 07;7(5):929-937.
    PMID: 27132518 DOI: 10.1016/j.ttbdis.2016.04.013
    Ticks are vectors in the transmission of many important infectious diseases in human and animals. Ticks can be readily found in the semi-forested areas such as the settlements of the indigenous people in Malaysia, the Orang Asli. There is still minimal information available on the bacterial agents associated with ticks found in Malaysia. We performed a survey of the bacterial communities associated with ticks collected from domestic animals found in two Orang Asli villages in Malaysia. We collected 62 ticks, microscopically and molecularly identified as related to Haemaphysalis wellingtoni, Haemaphysalis hystricis and Haemaphysalis bispinosa. Bacterial 16s rRNA hypervariable region (V6) amplicon libraries prepared from the tick samples were sequenced on the Ion Torrent PGM platform. We detected a total of 392 possible bacterial genera after pooling and sequencing 20 samples, indicating a diverse bacterial community profile. Dominant taxa include the potential tick endosymbiont, Coxiella. Other dominant taxa include the tick-associated pathogen, Rickettsia, and environmental bacteria such as Bacillus, Mycobacterium, Sphingomonas and Pseudomonas. Other known tick-associated bacteria were also detected, including Anaplasma, Ehrlichia, Rickettsiella and Wolbachia, albeit at very low abundance. Specific PCR was performed on selected samples to identify Rickettsia and Coxiella. Sequence of Rickettsia felis, which causes spotted fever in human and cats, was identified in one sample. Coxiella endosymbionts were detected in three samples. This study provides the baseline knowledge of the microbiome of ticks in Malaysia, focusing on tick-associated bacteria affecting the Orang Asli communities. The role of the herein found Coxiella and Rickettsia in tick physiology or disease transmission merits further investigation.
    Matched MeSH terms: Bacteria/isolation & purification*; DNA, Bacterial/genetics
  7. Bacterial community shift for monitoring the co-composting of oil palm empty fruit bunch and palm oil mill effluent anaerobic sludge
    Zainudin MHM, Ramli N, Hassan MA, Shirai Y, Tashiro K, Sakai K, et al.
    J Ind Microbiol Biotechnol, 2017 06;44(6):869-877.
    PMID: 28197796 DOI: 10.1007/s10295-017-1916-1
    A recently developed rapid co-composting of oil palm empty fruit bunch (OPEFB) and palm oil mill effluent (POME) anaerobic sludge is beginning to attract attention from the palm oil industry in managing the disposal of these wastes. However, a deeper understanding of microbial diversity is required for the sustainable practice of the co-compositing process. In this study, an in-depth assessment of bacterial community succession at different stages of the pilot scale co-composting of OPEFB-POME anaerobic sludge was performed using 454-pyrosequencing, which was then correlated with the changes of physicochemical properties including temperature, oxygen level and moisture content. Approximately 58,122 of 16S rRNA gene amplicons with more than 500 operational taxonomy units (OTUs) were obtained. Alpha diversity and principal component analysis (PCoA) indicated that bacterial diversity and distributions were most influenced by the physicochemical properties of the co-composting stages, which showed remarkable shifts of dominant species throughout the process. Species related to Devosia yakushimensis and Desemzia incerta are shown to emerge as dominant bacteria in the thermophilic stage, while Planococcus rifietoensis correlated best with the later stage of co-composting. This study proved the bacterial community shifts in the co-composting stages corresponded with the changes of the physicochemical properties, and may, therefore, be useful in monitoring the progress of co-composting and compost maturity.
    Matched MeSH terms: Bacteria/classification*; Bacteria/genetics; Bacteria/isolation & purification
  8. Fulltext Bacterial constituents of indoor air in a high throughput building in the tropics
    Li TC, Ambu S, Mohandas K, Wah MJ, Sulaiman LH, Murgaiyah M
    Trop Biomed, 2014 Sep;31(3):540-56.
    PMID: 25382482 MyJurnal
    Airborne bacteria are significant biotic constituents of bioaerosol. Bacteria at high concentrations in the air can compromise indoor air quality (IAQ) and result in many diseases. In tropical environments like Malaysia that extensively utilize air-conditioning systems, this is particularly significant due to continuous recirculation of indoor air and the potential implications for human health. Currently, there is a lack of knowledge regarding the impact of airborne bacteria on IAQ in Malaysia. This study was prompted by a need for reliable baseline data on airborne bacteria in the indoor environment of tropical equatorial Malaysia, that may be used as a reference for further investigations on the potential role played by airborne bacteria as an agent of disease in this region. It was further necessitated due to the threat of bioterrorism with the potentiality of release of exotic pathogenic microorganisms into indoor or outdoor air. Before scientists can detect the latter, a gauge of the common microorganisms in indoor (as well as outdoor) air needs to be ascertained, hence the expediency of this study. Bacterial counts from the broad-based and targeted study were generally in the order of 10(2) colony-forming units (CFU) per m(3) of air. The most prevalent airborne bacteria found in the broad-based study that encompassed all five levels of the building were Gram-positive cocci (67.73%), followed by Gram-positive rods (24.26%) and Gram-negative rods (7.10%). Gram-negative cocci were rarely detected (0.71%). Amongst the genera identified, Kytococcus sp., Micrococcus sp., Staphylococcus sp., Leifsonia sp., Bacillus sp. and Corynebacterium sp. predominated in indoor air. The most dominant bacterial species were Kytococcus sedentarius, Staphylococcus epidermidis and Micrococcus luteus. The opportunistic and nosocomial pathogen, Stenotrophomonas maltophilia was also discovered at a high percentage in the cafeteria. The bacteria isolated in this study have been increasingly documented to cause opportunistic infections in immuno-compromised patients, sometimes with fatal outcomes. Furthermore, some of them are becoming increasingly resistant to antibiotics. Hence, we propose that indoor reservoirs of these bacteria and their associated clinical and more subtle health effects, if any, be investigated further.
    Matched MeSH terms: Bacteria/classification*; Bacteria/isolation & purification*
  9. Fulltext Bacterial contamination of hospital disinfectants
    Keah KC, Jegathesan M, Tan SC, Chan SH, Chee OM, Cheong YM, et al.
    Med J Malaysia, 1995 Dec;50(4):291-7.
    PMID: 8668045
    A study to determine contamination of diluted disinfectants at different points in preparation and use in 6 Malaysian hospitals was done using the in-use test. A growth of > or = 250 organisms/ml was taken as an indication of contamination. A total of 342 (7.9%) of the 4316 freshly diluted samples collected from disinfectant bottles in the pharmacy were found to be contaminated. The bacterial isolates obtained were Pseudomonas spp. (42.4%), Moraxella spp. (22.0%), Flavobacterium spp. (11.6%) and Enterobacter spp. (4.2%). Three hundred and sixty seven out of 2278 ward stock were contaminated. The isolates were Pseudomonas spp. (48.6%), Moraxella spp. (17.8%), Acinetobacter spp. (8.9%) and Flavobacterium spp. (7.0%). Of the 9265 disinfectants in-use, 1519 (16.4%) were contaminated. Among the organisms isolated were Pseudomonas spp. (44.3%), Bacillus spp. (13.0%), Enterobacter spp. (9.5%) and Acinetobacter spp. (7.3%). The results indicated a high level of contamination of diluted disinfectants prepared in the pharmacy, stored and used in the wards. This gave a high index of suspicion that recommendations for cleaning of disinfectant containers before refilling, handling of diluted stock solutions and using of disinfectants were not closely adhered to. Standard disinfection procedures outlined in the disinfection and sterilization policy by the Ministry of Health should therefore be followed.
    Matched MeSH terms: Bacteria/isolation & purification*
  10. Bacterial detection: from microscope to smartphone
    Gopinath SC, Tang TH, Chen Y, Citartan M, Lakshmipriya T
    Biosens Bioelectron, 2014 Oct 15;60:332-42.
    PMID: 24836016 DOI: 10.1016/j.bios.2014.04.014
    The ubiquitous nature of bacteria enables them to survive in a wide variety of environments. Hence, the rise of various pathogenic species that are harmful to human health raises the need for the development of accurate sensing systems. Sensing systems are necessary for diagnosis and epidemiological control of pathogenic organism, especially in the food-borne pathogen and sanitary water treatment facility' bacterial populations. Bacterial sensing for the purpose of diagnosis can function in three ways: bacterial morphological visualization, specific detection of bacterial component and whole cell detection. This paper provides an overview of the currently available bacterial detection systems that ranges from microscopic observation to state-of-the-art smartphone-based detection.
    Matched MeSH terms: Bacteria/cytology*; Bacteria/isolation & purification*
  11. Bacterial disinfection and cell assessment post ultraviolet-C LED exposure for wound treatment
    Sheikh J, Swee TT, Saidin S, Yahya AB, Malik SA, Yin JSS, et al.
    Med Biol Eng Comput, 2021 May;59(5):1055-1063.
    PMID: 33866479 DOI: 10.1007/s11517-021-02360-8
    Ultraviolet-C sourced LED (UVC-LED) has been widely used for disinfection purposes due to its germicidal spectrum. In this study, the efficiencies of UVC-LED for Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus) disinfections were investigated at three exposure distances (1, 1.5, and 2 cm) and two exposure times (30 and 60 s). The respective bacterial inhibition zones were measured, followed by a morphological analysis under SEM. The viabilities of human skin fibroblast cells were further evaluated under the treatment of UVC-LED with the adoption of aforesaid exposure parameters. The inhibition zones were increased with the increment of exposure distances and times. The highest records of 5.40 ± 0.10 cm P. aeruginosa inhibition and 5.43 ± 0.11 cm S. aureus inhibition were observed at the UVC-LED distance of 2 cm and 60-s exposure. Bacterial physical damage with debris formation and reduction in size were visualized following the UVC-LED exposures. The cell viability percentages were in a range of 75.20-99.00% and 82-100.00% for the 30- and 60-s exposures, respectively. Thus, UVC-LED with 275-nm wavelength is capable in providing bacterial disinfection while maintaining accountable cell viability which is suitable to be adopted in wound treatment. Bacterial disinfection and human skin fibroblast cell assessment using UVC-LED.
    Matched MeSH terms: Bacteria
  12. Fulltext Bacterial diversity and composition in the fluid of pitcher plants of the genus Nepenthes
    Takeuchi Y, Chaffron S, Salcher MM, Shimizu-Inatsugi R, Kobayashi MJ, Diway B, et al.
    Syst Appl Microbiol, 2015 Jul;38(5):330-9.
    PMID: 26138047 DOI: 10.1016/j.syapm.2015.05.006
    Pitchers are modified leaves used by carnivorous plants for trapping prey. Their fluids contain digestive enzymes from the plant and they harbor abundant microbes. In this study, the diversity of bacterial communities was assessed in Nepenthes pitcher fluids and the composition of the bacterial community was compared to that in other environments, including the phyllosphere of Arabidopsis, animal guts and another pitcher plant, Sarracenia. Diversity was measured by 454 pyrosequencing of 16S rRNA gene amplicons. A total of 232,823 sequences were obtained after chimera and singleton removal that clustered into 3260 distinct operational taxonomic units (OTUs) (3% dissimilarity), which were taxonomically distributed over 17 phyla, 25 classes, 45 orders, 100 families, and 195 genera. Pyrosequencing and fluorescence in situ hybridization yielded similar estimates of community composition. Most pitchers contained high proportions of unique OTUs, and only 22 OTUs (<0.6%) were shared by ≥14/16 samples, suggesting a unique bacterial assemblage in each pitcher at the OTU level. Diversity analysis at the class level revealed that the bacterial communities of both opened and unopened pitchers were most similar to that of Sarracenia and to that in the phyllosphere. Therefore, the bacterial community in pitchers may be formed by environmental filtering and/or by phyllosphere bacteria.
    Matched MeSH terms: Bacteria/classification*; Bacteria/genetics*
  13. Bacterial diversity associated with empty oil palm fruit bunch compost as revealed by cultivation-independent analyses of PCR-amplified 16S rRNA genes
    Liew PW, Jong BC, Goh CM, Ahmad M
    J Gen Appl Microbiol, 2009 Jun;55(3):233-40.
    PMID: 19590151
    Matched MeSH terms: Bacteria/classification*; Bacteria/genetics; Bacteria/isolation & purification; Genes, Bacterial/genetics
  14. Bacterial dynamics associated with algal antibacterial substances during post harvest desiccation process of Sargassum stolonifolium Phang et Yoshida
    Vairappan CS
    Indian J Exp Biol, 2003 Aug;41(8):837-45.
    PMID: 15248481
    Brown algae of genus Sargassum are known to produce relatively higher amount of alginic acid. Optimal extraction of this algalcolloid for local consumption requires in-depth studies on post-harvest treatment of the algal fronds. Present investigation endeavors to establish the dynamics and inter-relationship of moisture content and bacteria found on the surface of the alga and alginic acid content during post-harvest desiccation of Sargassum stolonifolium Phang et Yoshida. Harvested fronds were subjected to desiccation for 31 days and bacterial dynamics were monitored with relation to moisture content and water activity index (a(w)). There was 85% decrease in moisture content, however, a(w) showed a more gradual decrease. Total bacterial count increased during the first week and attained maximal value on day 7. Thereafter, a drastic decrease was seen until day 14, followed by a gradual decline. Six species of bacteria were isolated and identified, i.e. Azomonas punctata, Azomonas sp., Escherichia coli, Micrococcus sp., Proteus vulgaris and Vibrio alginolyticus. Calculated ratios for increase in alginic acid content and decrease in moisture content were almost the same throughout the desiccation process, implying that extracellular alginase-producing bacteria did not use the alginic acid produced by the algae as its carbon source. It became apparent that drastic decrease in bacterial count after day 7 could not be attributed to salinity, moisture content, a(w) or lack of carbon source for the bacteria. The possible exposure of these bacteria to algal cell sap which is formed due to the rupture of algal cells was seen as the most likely reason for the drop in bacterial population. Scanning electron microscope (SEM) micrograph taken on day 10 of desiccation showed the presence of cracks and localities where bacteria were exposed to algal cell sap. In vitro antibacterial tests were carried out to verify the effect of algal extracts. Separation and purification of crude algal extracts via bioassay guided separation methodology revealed the identity of active compounds (i.e. gylcolipids and free fatty acids) involved in this inherently available antibacterial defense mechanism during algal desiccation.
    Matched MeSH terms: Gram-Negative Bacteria/drug effects; Gram-Negative Bacteria/growth & development; Gram-Positive Bacteria/drug effects; Gram-Positive Bacteria/growth & development
  15. Bacterial endosymbiont inhabiting Leucaena leucocephala leaves and their antioxidant and antidiabetic potential
    Chigurupati S, Vijayabalan S, Selvarajan KK, Alhowail A, Kauser F
    J Complement Integr Med, 2020 Dec 22;18(2):319-325.
    PMID: 34187119 DOI: 10.1515/jcim-2020-0203
    OBJECTIVES: Research on endosymbionts is emerging globally and is considered as a potential source of bioactive phytochemicals. The present study examines the antioxidant and antidiabetic of the endophytic crude extract isolated from Leucaena leucocephala leaves.

    METHODS: Endophytic bacteria were isolated from the leaves of L. leucocephala and 16S rRNA gene sequencing was used to establish their identity. The in vitro antioxidant effect of endophytic crude extract (LL) was evaluated using 2-diphenyl-1-picrylhydrazyl (DPPH) and 2, 2'-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS) free radical scavenging methods. The in vitro antidiabetic properties of LL were evaluated using α-amylase and α-glucosidase enzyme inhibition assay.

    RESULTS: The isolated endophytic bacteria were identified as Cronobacter sakazakii. LL displayed potent free radical scavenging effect against ABTS and DPPH radicals with an inhibitory concentration 50% (IC50) value of 17.49 ± 0.06 and 11.3 ± 0.1 μg/mL respectively. LL exhibited α-amylase and α-glucosidase inhibition with an IC50 value of 23.3 ± 0.08 and 23.4 ± 0.1 μg/mL respectively compared to the standard drug (acarbose). Both glucose loaded normoglycemic rats and STZ induced diabetic rats treated with LL (200 mg/kg) exhibited a considerable reduction in blood glucose levels p<0.01 after 8 h of treatment when compared to normal and diabetic control rats respectively.

    CONCLUSIONS: Thus, the study shows that LL has a wellspring of natural source of antioxidants, and antidiabetic agents and phytoconstituents present in endophytes could be the rich source for bioactive compounds.

    Matched MeSH terms: Bacteria
  16. Bacterial extracellular vesicles in biofluids as potential diagnostic biomarkers
    Su KY, Koh Kok JY, Chua YW, Ong SD, Ser HL, Pusparajah P, et al.
    Expert Rev Mol Diagn, 2022 Dec;22(12):1057-1062.
    PMID: 36629056 DOI: 10.1080/14737159.2022.2166403
    INTRODUCTION: Extracellular vesicles (EVs) are spherical membrane-derived lipid bilayers released by cells. The human microbiota consists of trillions of microorganisms, with bacteria being the largest group secreting microbial EVs. The discovery of bacterial EVs (BEVs) has garnered interest among researchers as potential diagnostic markers, given that the microbiota is known to be associated with various diseases and EVs carry important macromolecular cargo for intercellular interaction.

    AREAS COVERED: The differential bacterial composition identified from BEVs isolated from biofluids between patients and healthy controls may be valuable for detecting diseases. Therefore, BEVs may serve as novel diagnostic markers. Literature search on PubMed and Google Scholar databases was conducted. In this special report, we outline the commonly used approach for investigating BEVs in biofluids, the 16S ribosomal RNA gene sequencing of V3-V4 hypervariable regions, and the recent studies exploring the potential of BEVs as biomarkers for various diseases.

    EXPERT OPINION: The emerging field of BEVs offers new possibilities for the diagnosis of various types of diseases, although there remain issues that need to be resolved in this research area to implement BEVs in clinical applications. Hence, it is important for future studies to take these challenges into consideration when investigating the diagnostic value of BEVs.

    Matched MeSH terms: Bacteria
  17. Fulltext Bacterial flora varies throughout the saltwater crocodile (Crocodylus porosus) gastrointestinal tract
    Siddiqui R, Maciver SK, Anuar TS, Khan NA
    Am J Vet Res, 2023 Aug 01;84(8).
    PMID: 37353216 DOI: 10.2460/ajvr.23.03.0061
    OBJECTIVE: The objective of this study was to determine bacterial flora throughout the gastrointestinal tract of a saltwater crocodile (Crocodylus porosus) using 16S rRNA gene analysis.

    ANIMALS: A convention on international trade in endangered species (CITES) of wild fauna and flora registered crocodile farm, provided a healthy male saltwater crocodile, Crocodylus porosus for this study.

    PROCEDURES: Three samples were taken from the oral cavity, 3 samples from the proximal region of the small intestine (jejunum), and 3 samples from the distal part of the large intestine of the gastrointestinal tract of C. porosus were obtained using sterile cotton swabs. Next, swabs were placed in 15 mL sterile centrifuge tubes, individually, and kept on ice for immediate transportation to the laboratory. This was followed by 16S rRNA gene analysis using specific primers (341F-CCTAYGGGRBGCASCAG, and 806R-GGACTACNNGGGTATCTAAT). Amplicons were sequenced on Illumina paired-end platform, and bacterial gastrointestinal communities, the relative abundance of taxa, and principal component and coordinate analysis were performed.

    RESULTS: The findings revealed that bacterial community structures from differing regions exhibited several differences. The number of observed bacterial operational taxonomic units (OTUs) was 153 in the oral cavity, 239 in the small intestine, and 119 in the large intestine of C. porosus. The small intestine reflects the highest richness. In contrast, the large intestine exhibited the least richness of microbial communities. Relative abundance of taxa showed that Proteobacteria, Bacteroidetes, and Firmicutes were dominant in all 3 sample sites. Pseudomonas differed in the oral cavity and the large intestine, with the latter exhibiting less distribution of Pseudomonas. Stenotrophomonas and Castellaniella were higher in the oral cavity, while the relative abundance of Comamonas and Salmonella was higher in the small intestine. Conversely, the relative abundance of Salmonella and Pannonibacter was augmented in the large intestine.

    CLINICAL RELEVANCE: For the first time, this study demonstrates the bacterial diversity along the segments of the gastrointestinal tract of C. porosus. Bacterial flora varies throughout the gastrointestinal tract. Although further studies using large cohorts are warranted; however, our findings suggest that microbiome composition may have the potential as a biomarker in determining the overall health and well-being of C. porosus.

    Matched MeSH terms: Bacteria/genetics
  18. Fulltext Bacterial identification process using BactFinder© mobile application
    Nadiawati Alias, Nor Hasima Mahmod, Noor Afiza Badaluddin, Mohammad Khairul Asyraf Ridzuan
    Jurnal Inovasi Malaysia, 2019;2(2):1-18.
    MyJurnal
    BactFinder© is an interactive and mobile application built to facilitate bacteria identification. As widely known, bacteria are composed of large domains of prokaryotic microorganisms which are various in types, hence the identification of these bacterial groups requires a systematic and orderly identification process. Through this mobile app, experimental results from biochemical and bacterial morphological tests carried out in the laboratory before hand must be submitted to the application before bacterial identification can be performed. Previously, academics user and students have to refer to many references such as research books and related academic journals in order to finalise their bacteria identification. This process, of course, will take relatively longer time and less effective. This BactFinder© mobile application is equipped with a database of 19 types of biochemical tests including bacteria morphology. The database was built based on Bergey’s Manual of Systematic Bacteriology, Bergey’s Manual of Determinative Bacteriology and other related scientific journals. The BactFinder© mobile app has been proved able to provide fast (± 2 seconds) and precise responses in helping students and academics user in the process of identifying bacteria species in the lab. This application is also suitable for undergraduate, post-graduate and academicians in the field of microbiology, biotechnology and science in general.
    Matched MeSH terms: Bacteria
  19. Bacterial immunity and immunogenesis of normal human salivary IgA and serum IgG2 antiphospholipid autoantibody: a link?
    Cheng HM, Sam CK
    Immunol Lett, 1990 Oct;26(1):7-10.
    PMID: 2276764
    The anti-phospholipid antibody (aPL) in 26 heat-inactivated normal human sera (NHS) was tested for IgG subclass in ELISA. The specific antibody in NHS included all four IgG antibody subclasses, as well as IgA. The incidence of IgG subclasses ranged from 50% (13/26) for IgG1 to 92% (24/26) for IgG2. Specific IgA anti-phospholipid antibody (aPL) was detected by ELISA in 38% (28/73) of normal human saliva. The salivary IgA aPL bound preferentially to anionic phospholipids including cardiolipin, phosphatidylserine and phosphatidic acid but not to phosphatidylcholine or sphingomyelin. Unlike aPL in normal human sera, aPL in saliva was predominantly not associated with the previously described heat-labile inhibitor of aPL. This may indicate a role of salivary IgA aPL in local immunity by binding to cross-reactive bacterial cell surface components including phospholipids.
    Matched MeSH terms: Bacteria/immunology*
  20. Bacterial microbiome of Coptotermes curvignathus (Isoptera: Rhinotermitidae) reflects the coevolution of species and dietary pattern
    King JH, Mahadi NM, Bong CF, Ong KH, Hassan O
    Insect Sci, 2014 Oct;21(5):584-96.
    PMID: 24123989 DOI: 10.1111/1744-7917.12061
    Coptotermes curvignathus Holmgren is capable of feeding on living trees. This ability is attributed to their effective digestive system that is furnished by the termite's own cellulolytic enzymes and cooperative enzymes produced by their gut microbes. In this study, the identity of an array of diverse microbes residing in the gut of C. curvignathus was revealed by sequencing the near-full-length 16S rRNA genes. A total of 154 bacterial phylotypes were found. The Bacteroidetes was the most abundant phylum and accounted for about 65% of the gut microbial profile. This is followed by Firmicutes, Actinobacteria, Spirochetes, Proteobacteria, TM7, Deferribacteres, Planctomycetes, Verrucomicrobia, and Termite Group 1. Based on the phylogenetic study, this symbiosis can be a result of long coevolution of gut enterotypes with the phylogenic distribution, strong selection pressure in the gut, and other speculative pressures that determine bacterial biome to follow. The phylogenetic distribution of cloned rRNA genes in the bacterial domain that was considerably different from other termite reflects the strong selection pressures in the gut where a proportional composition of gut microbiome of C. curvignathus has established. The selection pressures could be linked to the unique diet preference of C. curvignathus that profoundly feeds on living trees. The delicate gut microbiome composition may provide available nutrients to the host as well as potential protection against opportunistic pathogen.
    Matched MeSH terms: Bacteria/classification; Bacteria/genetics; Bacteria/isolation & purification; Bacterial Proteins/genetics; Bacterial Physiological Phenomena*
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