Displaying publications 81 - 100 of 929 in total

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  1. Fulltext Respiratory microorganisms in acute pharyngitis patients: Identification, antibiotic prescription patterns and appropriateness, and antibiotic resistance in private primary care, central Malaysia
    Bo ZM, Tan WK, Chong CSC, Lye MS, Parmasivam S, Pang ST, et al.
    PLoS One, 2022;17(11):e0277802.
    PMID: 36395327 DOI: 10.1371/journal.pone.0277802
    Acute pharyngitis (AP) is a common reason for private primary care consultations, thus providing an avenue for widespread antibiotic intake among the community. However, there is limited data on the antibiotic prescription appropriateness and resistance information in the Malaysian private primary care setting, therefore, this study aimed to investigate the prevalence of isolated viruses and bacteria, antibiotic resistance patterns, antibiotic prescription patterns and appropriateness by general practitioners (GPs) and factors affecting antibiotic resistance and antibiotic prescription patterns. To investigate, a cross-sectional study was conducted among 205 patients presenting with AP symptoms at private primary care clinics in central Malaysia from 3rd January 2016 to 30th November 2016. Throat swabs were collected from 205 AP patients for two purposes: (i) the detection of four common respiratory viruses associated with AP via reverse-transcription real-time PCR (qRT-PCR); and (ii) bacterial identification using matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS). Bacterial isolates were then subjected to antibiotic susceptibility screening and McIsaac scoring was calculated post-prescription based on GP selection of criteria. Generalized estimating equations analysis with multiple logistic regression was conducted to identify factors associated with presence of virus and antibiotic prescription. The results showed that 95.1% (195/205) of patients had at least one of the four viruses, with rhinovirus (88.5%) being the most prevalent, followed by adenovirus (74.9%), influenza A virus (4.6%) and enterovirus (2.1%). A total of 862 non-repetitive colonies were isolated from the culture of throat swabs from 205 patients who were positive for bacteria. From a total of 22 genera, Streptococcus constitutes the most prevalent bacteria genus (40.9%), followed by Neisseria (20%), Rothia (13.0%), Staphylococcus (11%) and Klebsiella (4.9%). Only 5 patients carried group A beta-hemolytic streptococci (GABHS). We also report the presence of vancomycin-resistant S. aureus or VRSA (n = 9, 10.1%) among which one isolate is a multidrug-resistant methicillin-resistant S. aureus (MDR-MRSA), while 54.1% (n = 111) were found to carry at least one antibiotic-resistant bacteria species. Application of the McIsaac scoring system indicated that 87.8% (n = 180) of patients should not be prescribed antibiotics as the majority of AP patients in this study had viral pharyngitis. The antibiotic prescription appropriateness by applying post-prescription McIsaac scoring was able to rule out GABHS pharyngitis in this sample with a GABHS culture-positive sensitivity of 40% (n = 2/5) and specificity of 90% (180/200). In conclusion, antibiotic-resistant throat isolates and over-prescription of antibiotics were observed and McIsaac scoring system is effective in guiding GPs to determine occurrences of viral pharyngitis to reduce unnecessary antibiotic prescription.
    Matched MeSH terms: Anti-Bacterial Agents/pharmacology; Anti-Bacterial Agents/therapeutic use; Bacteria
  2. Insights into complex nanopillar-bacteria interactions: Roles of nanotopography and bacterial surface proteins
    Ishak MI, Jenkins J, Kulkarni S, Keller TF, Briscoe WH, Nobbs AH, et al.
    J Colloid Interface Sci, 2021 Dec 15;604:91-103.
    PMID: 34265695 DOI: 10.1016/j.jcis.2021.06.173
    Nanopillared surfaces have emerged as a promising strategy to combat bacterial infections on medical devices. However, the mechanisms that underpin nanopillar-induced rupture of the bacterial cell membrane remain speculative. In this study, we have tested three medically relevant poly(ethylene terephthalate) (PET) nanopillared-surfaces with well-defined nanotopographies against both Gram-negative and Gram-positive bacteria. Focused ion beam scanning electron microscopy (FIB-SEM) and contact mechanics analysis were utilised to understand the nanobiophysical response of the bacterial cell envelope to a single nanopillar. Given their importance to bacterial adhesion, the contribution of bacterial surface proteins to nanotopography-mediated cell envelope damage was also investigated. We found that, whilst cell envelope deformation was affected by the nanopillar tip diameter, the nanopillar density affected bacterial metabolic activities. Moreover, three different types of bacterial cell envelope deformation were observed upon contact of bacteria with the nanopillared surfaces. These were attributed to bacterial responses to cell wall stresses resulting from the high intrinsic pressure caused by the engagement of nanopillars by bacterial surface proteins. Such influences of bacterial surface proteins on the antibacterial action of nanopillars have not been previously reported. Our findings will be valuable to the improved design and fabrication of effective antibacterial surfaces.
    Matched MeSH terms: Bacteria; Bacterial Adhesion; Bacterial Proteins*
  3. Antibiotics' susceptibility patterns of bacterial isolates causing lower respiratory tract infections in ICU patients at referral hospitals in Namibia
    Simeon P, Godman B, Kalemeera F
    Hosp Pract (1995), 2021 Dec;49(5):356-363.
    PMID: 34436942 DOI: 10.1080/21548331.2021.1973825
    BACKGROUND: Lower respiratory tract infections (LRTIs) are a particular public health concern especially among sub-Saharan African countries. This is especially the case in Namibia, where LRTIs are currently the third leading cause of death, 300 deaths in children under 5 years of age. To reduce the burden of LRTIs on health systems and ensure appropriate patient management, it is critical to know the most prevalent pathogens leading to LRTIs and their susceptibility patterns in the local setting. Consequently, the objective of this study was to formulate cumulative antibiograms for Intensive Care Units (ICUs) of referral hospitals in Namibia to guide future antibiotic use.

    METHODS: A retrospective analytical cross-sectional study was conducted over 2 years. The cumulative antibiograms were constructed in accordance with current guidelines.

    RESULTS: A total of 976 first isolate cultures were obtained from ICUs of the different referral hospitals. K. pneumoniae (8.8%, 8.1%) was a predominant pathogen in Windhoek Central hospital ICU in 2017 and 2018. In Oshakati intermediate hospital ICU, Enterobacter sp. (22.2%) and P. aeruginosa (37.5%) were the common pathogens in 2017 and 2018, respectively. A. baumannii isolates were >90% susceptibility to colistin, carbapenems, and tigecycline in 2017. In 2017, K. pneumoniae isolates were more susceptible to carbapenems (94% and 93.8% among isolates), amikacin (89.3%), and tigecycline (88.7%). In 2018, K. pneumoniae isolates were 100% susceptible amikacin, colistin, and carbapenems. S. maltophilia isolates were more than 80% susceptible to all the tested antibiotics. S. aureus isolates were 100% susceptible to linezolid, rifampicin, teicoplanin, and vancomycin in 2017 and in 2018. Its susceptibility to these antibiotics did not change.

    CONCLUSION: The susceptibility patterns of the common isolated gram-negative pathogens were highly variable. Meropenem in combination with gentamicin is now the recommended antibiotic combination for empiric therapy for patients with LRTIs in Windhoek Central Hospital ICU.

    Matched MeSH terms: Gram-Negative Bacteria/drug effects*
  4. A review on the potential of polyhydroxyalkanoates production from oil-based substrates
    Chien Bong CP, Alam MNHZ, Samsudin SA, Jamaluddin J, Adrus N, Mohd Yusof AH, et al.
    J Environ Manage, 2021 Nov 15;298:113461.
    PMID: 34435568 DOI: 10.1016/j.jenvman.2021.113461
    Polyhydroxyalkanoate (PHA) is a type of polyesters produced in the form of accumulated intracellular granules by many microorganisms. It is viewed as an environmentally friendly bioproduct due to its biodegradability and biocompatibility. The production of the PHA using oil substrates such as waste oil and plant oil, has gained considerable attention due to the high product yield and lower substrate cost. Nevertheless, the PHA fermentation using oil substrate is complicated due to the heterogenous fatty acid composition, varied bio-accessibility and possible inhibitory effect on the bacterial culture. This review presents the current state-of-the-art of PHA production from oil-based substrates. This paper firstly discusses the technical details, such as the choice of bacteria strain and fermentation conditions, characteristic of the oil substrate as well as the PHA composition and application. Finally, the paper discusses the challenges and prospects for up-scaling towards a cleaner and effective bioprocess. From the literature review, depending on the cell culture and the type of PHA produced, the oil platform can have a PHA yield of 0.2-0.8 g PHA/g oil substrate, with PHA content mostly from 40 to 90% of the cell dry weight. There is an on-going search for more effective oil-utilising PHA producers and lower cost substrate for effective PHA production. The final application of the PHA polymer influences the treatment needed during downstream processing and its economic performance. PHA with different compositions exhibits varied decomposition behaviour under different conditions, requiring further insight towards its management towards a sustainable circular economy.
    Matched MeSH terms: Bacteria
  5. The antibacterial activity of fluoroquinolone derivatives: An update (2018-2021)
    Jia Y, Zhao L
    Eur J Med Chem, 2021 Nov 15;224:113741.
    PMID: 34365130 DOI: 10.1016/j.ejmech.2021.113741
    Bacterial infection is amongst the most common diseases in community and hospital settings. Fluoroquinolones, exerting the antibacterial activity through binding to type II bacterial topoisomerase enzymes, DNA gyrase and topoisomerase IV, are mainstays of chemotherapy. At present, fluoroquinolones are the most valuable antibacterial agents used popularly. However, the emergence of more virulent and resistant pathogens by the development of either mutated DNA-binding proteins or efflux pump mechanism for fluoroquinolones results in an urgent demand to develop new fluoroquinolones to withstand the drug resistance and to obtain a broader spectrum of activity. This review aims to outline the recent advances of fluoroquinolone derivatives with antibacterial potential and to summarize the structure-activity relationship (SAR) so as to provide an insight for rational design of more active candidates, covering articles published between January 2018 and June 2021.
    Matched MeSH terms: Anti-Bacterial Agents/pharmacology; Anti-Bacterial Agents/therapeutic use*; Bacteria/drug effects*; Bacterial Infections/drug therapy*
  6. Fulltext A review of recent advances in the decontamination of mycotoxin and inactivation of fungi by ultrasound
    Hashemi Moosavi M, Mousavi Khaneghah A, Javanmardi F, Hadidi M, Hadian Z, Jafarzadeh S, et al.
    Ultrason Sonochem, 2021 Nov;79:105755.
    PMID: 34562735 DOI: 10.1016/j.ultsonch.2021.105755
    Innovative technologies for the pasteurization of food products have increased due to the global demand for higher-quality food products. In this regard, the current article aimed to provide an overview regarding the latest research on US application in the decontamination of fungi in food products and highlight the parameters influencing the effectiveness of this method. Therefore, the related article with inactivation of fungi and mycotoxins by ultrasound among last four years (2018-2021) by using terms such as 'mycotoxin,' 'inactivation,' 'ultrasound,' 'decontamination' among some international databases such as PubMed, Web of Science, Embase and Google Scholar" was retrieved. Ultrasound (US) is considered a non-thermal decontamination method for food products. In US, the release of energy due to the acoustic phenomenon destroys microorganisms. This technology is advantageous as it is inexpensive, eco-friendly, and does not negatively affect food products' food structure and organoleptic properties. The influence of the US on food structure and organoleptic properties dramatically depends on the intensity and energy density applied In addition, it can preserve higher levels of ascorbic acid, lycopene, and chlorophyll in sonicated food products. The treatment conditions, including frequency, intensity, duration, temperature, and processing pressure, influence the effectiveness of decontamination. However, US displays synergistic or antagonistic effects on bacteria, yeasts, molds, and mycotoxins when combined with other types of decontamination methods such as chemical and thermal approaches. Thus, further research is needed to clarify these effects. Overall, the application of US methods in the food industry for decreasing the microbial content of food products during processing has been applied. However, the use of US with other techniques needs to be studied further.
    Matched MeSH terms: Bacteria
  7. Quantitative microbiological risk assessment of complex microbial community in Prawn farm wastewater and applicability of nanoparticles and probiotics for eliminating of antibiotic-resistant bacteria
    Noman E, Al-Gheethi A, Radin Mohamed RMS, Talip B, Al-Sahari M, Al-Shaibani M
    J Hazard Mater, 2021 10 05;419:126418.
    PMID: 34171673 DOI: 10.1016/j.jhazmat.2021.126418
    The current review highlighted the quantitative microbiological risk assessment of Vibrio parahaemolyticus in Prawn farm wastewaters (PFWWs) and the applicability of nanoparticles for eliminating antibiotic-resistant bacteria (ARB). The high availability of the antibiotics in the environment and their transmission into human through the food-chain might cause unknown health effects. The aquaculture environments are considered as a reservoir for the antibiotic resistance genes (ARGs) and contributed effectively in the increasing of ABR. The metagenomic analysis is used to explore ARGs in the non-clinical environment. V. parahaemolyticus is among the pathogenic bacteria which are transmitted through sea food causing human acute gastroenteritis due to available thermostable direct hemolysin (tdh), adhesins, TDH related hemolysin (trh). The inactivation of pathogenic bacteria using nanoparticles act by disturbing the cell membrane, interrupting the transport system, DNA and mitochondria damage, and oxidizing the cellular component by reactive oxygen species (ROS). The chloramphenicol, nitrofurans, and nitroimidazole are among the prohibited drugs in fish and fishery product. The utilization of probiotics is the most effective and safe alternative for antibiotics in Prawn aquaculture. This review will ensure public understanding among the readers on how they can decrease the risk of the antimicrobial resistance distribution in the environment.
    Matched MeSH terms: Anti-Bacterial Agents/pharmacology; Bacteria/genetics
  8. Mechanistic actions and contributing factors affecting the antibacterial property and cytotoxicity of graphene oxide
    Pulingam T, Thong KL, Appaturi JN, Lai CW, Leo BF
    Chemosphere, 2021 Oct;281:130739.
    PMID: 34004516 DOI: 10.1016/j.chemosphere.2021.130739
    Recent advances in the field of nanotechnology contributed to the increasing use of nanomaterials in the engineering, health and biological sectors. Graphene oxide (GO) has great potentials as it could be fine-tuned to be adapted into various applications, especially in the electrical, electronic, industrial and clinical fields. One of the important applications of GO is its use as an antibacterial material due to its promising activity against a broad range of bacteria. However, our understanding of the mechanism of action of GO towards bacteria is still lacking and is often less described. Therefore, a comprehensive overview of bactericidal mechanistic actions of GO and the roles of physicochemical factors including size, aggregation, functionalization and adsorption behavior contributing to its antibacterial activities are described in this review. As the use of GO is expected to increase exponentially in the health sector, the cytotoxicity of GO among the cell lines is also discussed. Thus, this review emphasizes the physicochemical characteristics of GO that can be tailored for optimal antibacterial properties that is of importance to the health industry.
    Matched MeSH terms: Anti-Bacterial Agents/toxicity; Bacteria
  9. Fulltext Geographic Expansion of Banana Blood Disease in Southeast Asia
    Ray JD, Subandiyah S, Rincon-Florez VA, Prakoso AB, Mudita IW, Carvalhais LC, et al.
    Plant Dis, 2021 Oct;105(10):2792-2800.
    PMID: 33973808 DOI: 10.1094/PDIS-01-21-0149-RE
    Blood disease in bananas caused by Ralstonia syzygii subsp. celebesensis is a bacterial wilt causing significant crop losses in Indonesia and Malaysia. Disease symptoms include wilting of the plant and red-brown vascular staining, internal rot, and discoloration of green banana fruit. There is no known varietal resistance to this disease in the Musa genus, although variation in susceptibility has been observed, with the popular Indonesian cooking banana variety Kepok being highly susceptible. This study established the current geographic distribution of Blood disease in Indonesia and confirmed the pathogenicity of isolates by Koch's postulates. The long-distance distribution of the disease followed an arbitrary pattern indicative of human-assisted movement of infected banana materials. In contrast, local or short-distance spread radiated from a single infection source, indicative of dispersal by insects and possibly contaminated tools, water, or soil. The rapid expansion of its geographical range makes Blood disease an emerging threat to banana production in Southeast Asia and beyond.
    Matched MeSH terms: Bacteria
  10. Fulltext Development of Antibacterial, Degradable and pH-Responsive Chitosan/Guar Gum/Polyvinyl Alcohol Blended Hydrogels for Wound Dressing
    Khan MUA, Iqbal I, Ansari MNM, Razak SIA, Raza MA, Sajjad A, et al.
    Molecules, 2021 Sep 30;26(19).
    PMID: 34641480 DOI: 10.3390/molecules26195937
    The present research is based on the fabrication preparation of CS/PVA/GG blended hydrogel with nontoxic tetra orthosilicate (TEOS) for sustained paracetamol release. Different TEOS percentages were used because of their nontoxic behavior to study newly designed hydrogels' crosslinking and physicochemical properties. These hydrogels were characterized using Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and wetting to determine the functional, surface morphology, hydrophilic, or hydrophobic properties. The swelling analysis in different media, degradation in PBS, and drug release kinetics were conducted to observe their response against corresponding media. The FTIR analysis confirmed the components added and crosslinking between them, and surface morphology confirmed different surface and wetting behavior due to different crosslinking. In various solvents, including water, buffer, and electrolyte solutions, the swelling behaviour of hydrogel was investigated and observed that TEOS amount caused less hydrogel swelling. In acidic pH, hydrogels swell the most, while they swell the least at pH 7 or higher. These hydrogels are pH-sensitive and appropriate for controlled drug release. These hydrogels demonstrated that, as the ionic concentration was increased, swelling decreased due to decreased osmotic pressure in various electrolyte solutions. The antimicrobial analysis revealed that these hydrogels are highly antibacterial against Gram-positive (Staphylococcus aureus and Bacillus cereus) and Gram negative (Pseudomonas aeruginosa and Escherichia coli) bacterial strains. The drug release mechanism was 98% in phosphate buffer saline (PBS) media at pH 7.4 in 140 min. To analyze drug release behaviour, the drug release kinetics was assessed against different mathematical models (such as zero and first order, Higuchi, Baker-Lonsdale, Hixson, and Peppas). It was found that hydrogel (CPG2) follows the Peppas model with the highest value of regression (R2 = 0.98509). Hence, from the results, these hydrogels could be a potential biomaterial for wound dressing in biomedical applications.
    Matched MeSH terms: Anti-Bacterial Agents/administration & dosage*; Anti-Bacterial Agents/chemistry; Bacteria/drug effects*
  11. Gene expression of microbial gelatinase activity for porcine gelatine identification
    Shahimi S, Lamri MF, Abd Mutalib S, Mohd Khalid R, Md Tab M, Khairuddin F
    Food Chem, 2021 Sep 01;355:129586.
    PMID: 33773458 DOI: 10.1016/j.foodchem.2021.129586
    In order to invent a porcine gelatine detection device using microbial resources, bacterial enzymes with a preference towards porcine gelatine and their candidate genes were evaluated. Five (n = 5) bacterial strains isolated from hot spring water and wet clay, Malaysia were screened for their gelatinase activity. The gelatinase enzyme was extracted and purified using ammonium sulphate precipitation prior to performing gelatinase assay on porcine, bovine and fish gelatine medium substrates. The G2 strain or Enterobacter aerogenes (Strain EA1) was selected for whole genome sequenced after showing a consistent trend of preference towards porcine gelatine. The gelatinase candidate gene gelEA1_9 was cloned and expressed. Based on one-way analysis of variance (ANOVA) with POST-HOC Duncan test (α = 0.05), the final product of gelEA1_9 was identified as a novel gelatinase. This gelatinase presented no significant difference in activity towards porcine gelatine. Hence, the present study demonstrated an enzyme-substrate interaction for porcine gelatine identification.
    Matched MeSH terms: Bacteria
  12. Fulltext Development and Characterization of Calcium-Alginate Beads of Apigenin: In Vitro Antitumor, Antibacterial, and Antioxidant Activities
    Aldawsari MF, Ahmed MM, Fatima F, Anwer MK, Katakam P, Khan A
    Mar Drugs, 2021 Aug 20;19(8).
    PMID: 34436306 DOI: 10.3390/md19080467
    The objective of this work was to develop sustained-release Ca-alginate beads of apigenin using sodium alginate, a natural polysaccharide. Six batches were prepared by applying the ionotropic gelation technique, wherein calcium chloride was used as a crosslinking agent. The beads were evaluated for particle size, drug loading, percentage yield, and in vitro drug release. Particle size was found to decrease, and drug entrapment efficiency was enhanced with an increase in the polymer concentration. The dissolution study showed sustained drug release from the apigenin-loaded alginate beads with an increase in the polymer proportion. Based on the dissolution profiles, BD6 formulation was optimized and characterized for FTIR, DSC, XRD, and SEM, results of which indicated successful development of apigenin-loaded Ca alginate beads. MTT assay demonstrated a potential anticancer effect against the breast cancer MCF-7 cell lines. The antimicrobial activity exhibited effective inhibition in the bacterial and fungal growth rate. The DPPH measurement revealed that the formulation had substantial antioxidant activity, with EC50 value slightly lowered compared to pure apigenin. A stability study demonstrated that the BD6 was stable with similar (f2) drug release profiles in harsh condition. In conclusion, alginate-based beads could be used for sustaining the drug release of poorly water-soluble apigenin while also improving in vitro antitumor, antimicrobial, and antioxidant activity.
    Matched MeSH terms: Gram-Negative Bacteria/drug effects; Gram-Positive Bacteria/drug effects
  13. Fulltext Crocodylus porosus Gut Bacteria: A Possible Source of Novel Metabolites
    Khan NA, Soopramanien M, Maciver SK, Anuar TS, Sagathevan K, Siddiqui R
    Molecules, 2021 Aug 18;26(16).
    PMID: 34443585 DOI: 10.3390/molecules26164999
    Crocodiles are remarkable animals that have the ability to endure extremely harsh conditions and can survive up to a 100 years while being exposed to noxious agents that are detrimental to Homo sapiens. Besides their immunity, we postulate that the microbial gut flora of crocodiles may produce substances with protective effects. In this study, we isolated and characterized selected bacteria colonizing the gastrointestinal tract of Crocodylusporosus and demonstrated their inhibitory effects against three different cancerous cell lineages. Using liquid chromatography-mass spectrometry, several molecules were identified. For the first time, we report partial analyses of crocodile's gut bacterial molecules.
    Matched MeSH terms: Bacteria/isolation & purification*; Bacteria/metabolism
  14. Microalgal-bacterial granular sludge process for non-aerated aquaculture wastewater treatment
    Fan S, Ji B, Abu Hasan H, Fan J, Guo S, Wang J, et al.
    Bioprocess Biosyst Eng, 2021 Aug;44(8):1733-1739.
    PMID: 33772637 DOI: 10.1007/s00449-021-02556-0
    Microalgal-bacterial granular sludge (MBGS) process has become a focal point in treating municipal wastewater. However, it remains elusive whether the emerging process can be applied for the treatment of aquaculture wastewater, which contains considerable concentrations of nitrate and nitrite. This study evaluated the feasibility of MBGS process for aquaculture wastewater treatment. Result showed that the MBGS process was competent to remove respective 64.8%, 84.9%, 70.8%, 50.0% and 84.2% of chemical oxygen demand, ammonia-nitrogen, nitrate-nitrogen, nitrite-nitrogen and phosphate-phosphorus under non-aerated conditions within 8 h. The dominant microalgae and bacteria were identified to be Coelastrella and Rhodobacteraceae, respectively. Further metagenomics analysis implied that microbial assimilation was the main contributor in organics, nitrogen and phosphorus removal. Specifically, considerable nitrate and nitrite removals were also obtained with the synergy between microalgae and bacteria. Consequently, this work demonstrated that the MBGS process showed a prospect of becoming an environmentally friendly and efficient alternative in aquaculture wastewater treatment.
    Matched MeSH terms: Bacteria/metabolism*
  15. Emerging cold plasma treatment on rice grains: A mini review
    Ikmal Misnal MF, Redzuan N, Firdaus Zainal MN, Raja Ibrahim RK, Ahmad N, Agun L
    Chemosphere, 2021 Jul;274:129972.
    PMID: 33979941 DOI: 10.1016/j.chemosphere.2021.129972
    Future demand of rice is projected to increase with the increase of global population. However, the presence of bacteria, insects, and fungi has resulted in various changes in the physical and chemical characteristics of rice grain. To make it worse, the overuse of post-harvest chemicals (fungicide and pesticide) has caused possible risks to human health through either occupational or non-occupational exposure. For the last few years, cold plasma has been developed as an alternative non-thermal emerging technology for rice grains treatment due to its ability to inactivate or decontaminate pathogens without causing thermal damage and free of any harmful residues. Therefore, this review describes the operational mechanism of cold plasma treatment technology on rice grains, existing reactor system designs, and parameters influenced by the treatment technology (reactor design parameters and treatment process parameters). Possible advanced investigation on future reactor design modification as well as standard operating range of influenced parameters were suggested for improved efficiency and effectiveness of cold plasma treatment.
    Matched MeSH terms: Bacteria
  16. Culturable bacteria in adults of a Southeast Asian black fly, Simulium tani (Diptera:Simuliidae)
    Lee HY, Loong SK, Ya'cob Z, Low VL, Teoh BT, Ahmad-Nasrah SN, et al.
    Acta Trop, 2021 Jul;219:105923.
    PMID: 33878305 DOI: 10.1016/j.actatropica.2021.105923
    Although the microbiome of blood-feeding insects serves an integral role in host physiology, both beneficial and pathogenic, little is known of the microbial community of black flies. An investigation, therefore, was undertaken to identify culturable bacteria from one of Malaysia's most common black flies, Simulium tani Takaoka and Davies, using 16S rDNA sequencing, and then evaluate the isolates for antibiotic resistance and virulence genes. A total of 20 isolates representing 11 bacterial species in four genera were found. Five isolates showed β-hemolysis on Columbia agar, and virulence genes were found in three of these isolates. Some degree of resistance to six of the 12 tested antibiotics was found among the isolates. The baseline data from this study suggest rich opportunities for comparative studies exploring the diversity and roles of the microbiome of S. tani and other Southeast Asian black flies.
    Matched MeSH terms: Bacteria/drug effects; Bacteria/genetics; Bacteria/growth & development*; Bacteria/isolation & purification*; Drug Resistance, Bacterial
  17. Fermentation of blueberry and blackberry juices using Lactobacillus plantarum, Streptococcus thermophilus and Bifidobacterium bifidum: Growth of probiotics, metabolism of phenolics, antioxidant capacity in vitro and sensory evaluation
    Wu Y, Li S, Tao Y, Li D, Han Y, Show PL, et al.
    Food Chem, 2021 Jun 30;348:129083.
    PMID: 33517000 DOI: 10.1016/j.foodchem.2021.129083
    In this study, three potential probiotic strains were selected to ferment blueberry and blackberry juices. The viable cell counts of selected strains were increased by 0.4-0.7 log CFU/mL in berry juices environments after 48-h fermentation. Meanwhile, the contents of cyanindin-3-glucoside and peonidin-3-glucoside decreased over 30%. Heatmap presented an upgrade trend of syringic acid, ferulic acid, gallic acid and lactic acid during fermentation. However, the contents of p-coumaric acid, protocatechuic acid, chlorogenic acid, critic acid and malic acid showed downgrade trend. The metabolism of phenolics probably contributed to the enhancement of the ABTS radical scavenging activity (40%-60%) in fermented berry juices. Moreover, the three strains presented different capacities on changing the quality of berry juices according to the PCA and LDA analysis. The contents of individual organic acids had positive correlations with sensory quality, especially for sourness. Overall, probiotic fermentation could improve the sensory quality of berry juices.
    Matched MeSH terms: Bacteria/metabolism*
  18. Fulltext A Review on Bacterial Contribution to Lignocellulose Breakdown into Useful Bio-Products
    Chukwuma OB, Rafatullah M, Tajarudin HA, Ismail N
    Int J Environ Res Public Health, 2021 Jun 03;18(11).
    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
  19. Self-flocculation of enriched mixed microalgae culture in a sequencing batch reactor
    Gobi S, Gobi K, Lee KT, Vadivelu V
    Environ Sci Pollut Res Int, 2021 Jun;28(21):26595-26605.
    PMID: 33484460 DOI: 10.1007/s11356-021-12615-4
    Microalgae-based biodiesel has gained widespread interest as an alternative energy source. Low-cost microalgae harvesting technologies are important for economically feasible biodiesel production. This study investigated, for the first time, the impact of adaptation period and height to diameter (H/D) ratio of a reactor on the growth and self-flocculation of microalgae, without the addition of bacteria. Six reactors were grouped into three sets of experiments, and each reactor was operated for 30 days at similar operating conditions (volume exchange ratio = 25% and settling time = 30 min). In set 1, two 8-L reactors, H5a (H/D ratio: 5) and H8a (H/D ratio: 8), were operated under batch operation. In set 2, reactors H5b and H8b were operated as sequential batch reactors (SBRs) without an adaptation period. In set 3, the reactors H5c and H8c were operated as SBRs with an adaptation period. The findings showed a threefold improvement in biomass productivity for the higher H/D ratio (H8c) and a reduction in biomass loss for microalgae. The H8c reactor exhibited 95% settling efficiency within 5 days, in comparison to 30 days for the H5c reactor. This study demonstrated that a higher H/D ratio and the introduction of an adaptation period in SBR operation positively influences growth and self-flocculation of enriched mixed microalgae culture.
    Matched MeSH terms: Bacteria
  20. Fulltext Elucidation of Gram-Positive Bacterial Iron(III) Reduction for Kaolinite Clay Refinement
    Jing H, Liu Z, Kuan SH, Chieng S, Ho CL
    Molecules, 2021 May 21;26(11).
    PMID: 34064160 DOI: 10.3390/molecules26113084
    Recently, microbial-based iron reduction has been considered as a viable alternative to typical chemical-based treatments. The iron reduction is an important process in kaolin refining, where iron-bearing impurities in kaolin clay affects the whiteness, refractory properties, and its commercial value. In recent years, Gram-negative bacteria has been in the center stage of iron reduction research, whereas little is known about the potential use of Gram-positive bacteria to refine kaolin clay. In this study, we investigated the ferric reducing capabilities of five microbes by manipulating the microbial growth conditions. Out of the five, we discovered that Bacillus cereus and Staphylococcus aureus outperformed the other microbes under nitrogen-rich media. Through the biochemical changes and the microbial behavior, we mapped the hypothetical pathway leading to the iron reduction cellular properties, and found that the iron reduction properties of these Gram-positive bacteria rely heavily on the media composition. The media composition results in increased basification of the media that is a prerequisite for the cellular reduction of ferric ions. Further, these changes impact the formation of biofilm, suggesting that the cellular interaction for the iron(III)oxide reduction is not solely reliant on the formation of biofilms. This article reveals the potential development of Gram-positive microbes in facilitating the microbial-based removal of metal contaminants from clays or ores. Further studies to elucidate the corresponding pathways would be crucial for the further development of the field.
    Matched MeSH terms: Gram-Positive Bacteria/metabolism*
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