scholarly journals Partial Characterization of Bacteriocins Produced by Lactobacillus reuteri 2-20B and Pediococcus acidilactici 0-11A Isolated from Fura, a Millet-Based Fermented Food in Ghana

2013 ◽  
Vol 2 (1) ◽  
pp. 50 ◽  
Author(s):  
James Owusu-Kwarteng ◽  
Kwaku Tano-Debrah ◽  
Fortune Akabanda ◽  
Dennis S. Nielsen ◽  
Lene Jespersen
Keyword(s):  
Pathogenic Bacteria ◽  
Lactobacillus Reuteri ◽  
Proteolytic Enzymes ◽  
Bacteriocin Production ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Diffusion Method ◽  
Pediococcus Acidilactici ◽  
Media Composition ◽  
Wide Range

Cell-free supernatants (CFS) produced by 369 LAB strains previously isolated from fura and identified based on sequencing of their 16S rRNA genes were screened for their antagonistic activities against pathogenic bacteria including<em> Bacillus cereus</em> PA24, <em>Escherichia coli </em>SKN 541, <em>Enterococcus faecalis</em> 103907 CIP, <em>Staphylococcus aureus</em> ATCC 19095 and <em>Listeria</em> <em>monocytogenes</em> Scott A, using the agar well diffusion method. Bacteriocins of <em>Lactobacillus</em> <em>reuteri</em> 2-20B and <em>Pediococcus acidilactici</em> 0-11A were further evaluated for their stability when subjected to a range of pH conditions, enzymatic and heat treatments. Growth and bacteriocin production rates as well as influence of media composition on bacteriocin production were also evaluated. Cell free supernatants of <em>Lb</em>. <em>reuteri</em> and <em>Pd</em>. <em>acidilactici</em> strains exhibited the widest inhibitory activities whereas CFS of <em>Lb</em>. <em>fermentum</em> exhibited the least inhibitory activity towards the tested pathogens. Bacteriocins of <em>Lb</em>. <em>reuteri</em> 2-20B and <em>Pd</em>. <em>acidilactici</em> 0-11A retained their antibacterial activities over a wide range of pH. Whereas the antimicrobial activity of <em>Lb</em>. <em>reuteri</em> 2-20B was lost after being subjected to temperature of 90°C for 1 h, CFS of <em>Pd</em>. <em>acidilactici</em> 0-11A remained stable after autoclaving at 121°C for 15 min. Again, the antimicrobial activities of both <em>Lb</em>. <em>reuteri</em> 2-20B and <em>Pd</em>. <em>acidilactici</em> 0-11A were lost when the CFSs were subjected to the action of proteolytic enzymes but remained active under the actions of catalase, lipase and a-amylase. Production of bacteriocins by both <em>Lb</em>. <em>reuteri</em> 2-20B and <em>Pd</em>. <em>acidilactici</em> 0-11A were growth associated and influeced by media composition.

HIGH VAGINAL SWABS;

2017 ◽  
Vol 24 (04) ◽  
pp. 622-626
Author(s):  
Shamas Pervaiz ◽  
Faiza Sarwar ◽  
Abdul Rauf ◽  
Muhammad Saifullah
Keyword(s):  
Pathogenic Bacteria ◽  
Vaginal Discharge ◽  
Care Center ◽  
Diffusion Method ◽  
Sensitivity Testing ◽  
Gram Negative ◽  
Health Care Center ◽  
Sensitivity Pattern ◽  
Wide Range ◽  
Vaginal Swabs

Normal vaginal flora contains a wide range of microorganisms. Hydrogen peroxideproduced by Lactobacillus strains plays a vital role in maintaining the microenvironment of thevagina and in the inhibition of overgrowth of potentially pathogenic bacteria. Bacterial vaginosisBV is the main reason of vaginal discharge. Many gram positive and gram negative rods i.e.E.coli, Klebsiella, Proteus, Acinetobacter and Pseudomonas spp. are major contributors inbacterial vaginosis. Aim: The present study was conducted to elucidate the frequency of variousgram-negative rods in high vaginal swabs and sensitivity pattern of bacteria to antibiotics thatare currently used. Study Design: Cross sectional study. Setting: Department of Obstetricsand Gynecology of Benazir Bhutto Hospital Rawalpindi, a tertiary health care center for thepeople of Rawalpindi. Period: January 2015 to May 2016. Material and Methods: A total of220 High vaginal swabs (HVS) were collected both from indoor and outdoor patients presentingwith symptoms of vaginal discharge aged between 20 to 65 years. Swabs were inoculated onblood, Chocolate and MacConkey’s agar. After overnight incubation plates were examined forgrowth, colonial morphology, final confirmation was done on the basis of biochemical testingand API 20-E system (BioMerieux, France) up to species level. Antibiotic sensitivity testing wasdone by (modified Kirby-Bauer’s) disc diffusion method using amikacin, ampicillin, amoxicillinclavulanic acid, imipenem, ceftazidime, tigecycline, ciprofloxacin, sulzone and cefixime. Afterovernight incubation plates were examined to read the susceptibility zone. Results: Out of 220HVS samples, 100 samples showed bacterial growth and confirmed as Gram negative bacilli.Age wise distribution of infection showed highest rates b/w age 20-30 was 36% followed by 31-40 (23%), 41-50 (25%) and 11% above 50 years of age. Bacteria isolated from HVS were E.coli(53%), Klebsiella (22%), Pseudomonas (12%), citrobacter (6%), Proteus (5%) and Acinetobacter(2%) respectively. Highly sensitive antibiotics against bacteria were imipenem (96%), sulzone(90%) and Ciprofloxacin (88%), whereas least affective antibiotics against gram negative rodswere penicillins (ampicillin, amoxicillin-clavulanic acid), amikacin due to indiscriminate use ofantibiotics. Conclusion: High prevalence of gynecological infections demands that the patientswho have vaginosis must be investigated regularly and carefully through culture and identificationof causative bacteria. Emergence of antibiotic resistance must be controlled in order to avoidimproper use, frequent abuse, insufficient dosages, trouble-free availability of antibiotics andtreatment schedule must be designed subsequent to proper laboratory investigations.

scholarly journals Prevalence and molecular detection of fluoroquinolone-resistant genes (qnrA and qnrS) in Escherichia coli isolated from healthy broiler chickens

2018 ◽  
pp. 1720-1724 ◽  
Author(s):  
Shahin Mahmud ◽  
K. H. M. Nazmul Hussain Nazir ◽  
Md. Tanvir Rahman
Keyword(s):  
Escherichia Coli ◽  
Broiler Chickens ◽  
Molecular Detection ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Diffusion Method ◽  
Isolation And Identification ◽  
E Coli ◽  
Pcr Targeting ◽  
Apparently Healthy

Aim: The present study was carried out to determine the prevalence and molecular detection of fluoroquinolone-resistant Escherichia coli carrying qnrA and qnrS genes in healthy broiler chickens in Mymensingh, Bangladesh, and also to identify the genes responsible for such resistance. Materials and Methods: A total of 65 cloacal swabs were collected from apparently healthy chickens of 0-14 days (n=23) and 15-35 days (n=42) old. The samples were cultured onto Eosin Methylene Blue Agar, and the isolation and identification of the E. coli were performed based on morphology, cultural, staining, and biochemical properties followed by polymerase chain reaction (PCR) targeting E. coli 16S rRNA genes. The isolates were subjected to antimicrobial susceptibility test against five commonly used antibiotics under fluoroquinolone (quinolone) group, namely gatifloxacin, levofloxacin, moxifloxacin, ofloxacin, and pefloxacin by disk diffusion method. Detection of qnrA and qnrS genes was performed by PCR. Results: Among the 65 cloacal samples, 54 (83.08%) were found to be positive for E. coli. Antibiotic sensitivity test revealed that, of these 54 isolates, 18 (33.33%) were found to be resistant to at least one fluoroquinolone antibiotic. The highest resistance was observed against pefloxacin (61.11%). By PCR, of 18 E. coli resistant to fluoroquinolone, 13 (72.22%) were found to be positive for the presence of qnrS. None of the isolates were found positive for qnrA. Conclusion: Fluoroquinolone-resistant E. coli harboring qnrS genes is highly prevalent in apparently healthy broiler chickens and possesses a potential threat to human health.

scholarly journals Survey of bacteria associated with western corn rootworm life stages reveals no difference between insects reared in different soils

2018 ◽  
Author(s):  
Dalton C. Ludwick ◽  
Aaron C. Ericsson ◽  
Lisa N. Meihls ◽  
Michelle L.J. Gregory ◽  
Deborah L. Finke ◽  
...  
Keyword(s):  
Pest Management ◽  
Life Stage ◽  
Diabrotica Virgifera Virgifera ◽  
Western Corn Rootworm ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Corn Rootworm ◽  
Life Stages ◽  
Wide Range ◽  
Different Soils

AbstractWestern corn rootworm (Diabrotica virgifera virgifera LeConte) is a serious pest of maize (Zea mays L.) in North America and parts of Europe. With most of its life cycle spent in the soil feeding on maize root tissues, this insect is likely to encounter and interact with a wide range of soil and rhizosphere microbes. Our knowledge of the role of microbes in pest management and plant health remains incomplete. An important component of an effective pest management strategy is to know which microorganisms are present that could play a role in life history or management. For this study, insects were reared in soils from different locations. Insects were sampled at each life stage to determine the possible core bacteriome. Additionally, soil was sampled at each life stage and resulting bacteria were identified to determine the contribution of soil to the rootworm bacteriome, if any. We analyzed the V4 hypervariable region of bacterial 16S rRNA genes with Illumina MiSeq to survey the different species of bacteria associated with the insects and the soils. The bacterial community associated with insects was significantly different from that in the soil. Some differences appear to exist between insects from non-diapausing and diapausing colonies while no significant differences in community composition existed between the insects reared on different soils. Despite differences in the bacteria present in immature stages and in male and female adults, there is a possible core bacteriome of approximately 16 operational taxonomic units (i.e., present across all life stages). This research may give insights into how resistance to Bt develops, improved nutrition in artificial rearing systems, and new management strategies.

scholarly journals Daqu Fermentation Selects for Heat-ResistantEnterobacteriaceaeand Bacilli

2018 ◽  
Vol 84 (21) ◽  
Author(s):  
Zhiying Wang ◽  
Pan Li ◽  
Lixin Luo ◽  
David J. Simpson ◽  
Michael G. Gänzle
Keyword(s):  
Solid State ◽  
Heat Resistance ◽  
Pathogenic Bacteria ◽  
Starter Culture ◽  
Genomic Islands ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Content Type ◽  
Genetic Elements ◽  
Heat Resistant

ABSTRACTDaqu is a spontaneous solid-state cereal fermentation used as saccharification and starter culture in Chinese vinegar and liquor production. The evolution of microbiota in this spontaneous fermentation is controlled by the temperature profile, which reaches temperatures from 50 to 65°C for several days. Despite these high temperatures, mesophilicEnterobacteriaceae(includingCronobacter) and bacilli are present throughout Daqu fermentation. This study aimed to determine whether Daqu spontaneous solid-state fermentation selects for heat-resistant variants of these organisms. Heat resistance inEnterobacteriaceaeis mediated by the locus of heat resistance (LHR). One LHR-positive strain ofKosakonia cowaniiwas identified in Daqu, and it exhibited higher heat resistance than the LHR-negativeK. cowaniiisolated from malted oats. Heat resistance inBacillusendospores is mediated by thespoVA2moboperon. Out of 10 Daqu isolates of the speciesBacillus licheniformis,Brevibacillus parabrevis,Bacillus subtilis,Bacillus amyloliquefaciens, andBacillus velezensis, 5 did not containspoVA2mob, 3 contained one copy, and 2 contained two copies. The presence and copy number of thespoVA2moboperon increased the resistance of spores to treatment with 110°C. To confirm the selection of LHR- andspoVA2mob-positive strains during Daqu fermentation, the copy numbers of these genetic elements in Daqu samples were quantified by quantitative PCR (qPCR). The abundance of LHR and thespoVA2moboperon in community DNA relative to that of total bacterial 16S rRNA genes increased 3-fold and 5-fold, respectively, during processing. In conclusion, culture-dependent and culture-independent analyses suggest that Daqu fermentation selects for heat-resistantEnterobacteriaceaeand bacilli.IMPORTANCEDaqu fermentations select for mobile genetic elements conferring heat resistance inEnterobacteriaceaeand bacilli. The locus of heat resistance (LHR), a genomic island conferring heat resistance inEnterobacteriaceae, and thespoVA2moboperon, conferring heat resistance on bacterial endospores, were enriched 3- to 5-fold during Daqu fermentation and maturation. It is therefore remarkable that the LHR and thespoVA2moboperon are accumulated in the same food fermentation. The presence of heat-resistantKosakoniaspp. andBacillusspp. in Daqu is not of concern for food safety; however, both genomic islands are mobile and transferable to pathogenic bacteria or toxin-producing bacteria by horizontal gene transfer. The identification of the LHR and thespoVA2moboperon as indicators of fitness ofEnterobacteriaceaeand bacilli in Daqu fermentation provides insights into environmental sources of heat-resistant organisms that may contaminate the food supply.

scholarly journals Cold-Active Shewanella glacialimarina TZS-4T nov. Features a Temperature-Dependent Fatty Acid Profile and Putative Sialic Acid Metabolism

2021 ◽  
Vol 12 ◽  
Author(s):  
Muhammad Suleman Qasim ◽  
Mirka Lampi ◽  
Minna-Maria K. Heinonen ◽  
Berta Garrido-Zabala ◽  
Dennis H. Bamford ◽  
...  
Keyword(s):  
Phylogenetic Analysis ◽  
Sialic Acid ◽  
Sea Ice ◽  
Acid Metabolism ◽  
Elevated Temperatures ◽  
Consensus Sequence ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Wide Range ◽  
Cold Active

Species of genus Shewanella are among the most frequently identified psychrotrophic bacteria. Here, we have studied the cellular properties, growth dynamics, and stress conditions of cold-active Shewanella strain #4, which was previously isolated from Baltic Sea ice. The cells are rod-shaped of ~2μm in length and 0.5μm in diameter, and they grow between 0 and 25°C, with an optimum at 15°C. The bacterium grows at a wide range of conditions, including 0.5–5.5% w/v NaCl (optimum 0.5–2% w/v NaCl), pH 5.5–10 (optimum pH 7.0), and up to 1mM hydrogen peroxide. In keeping with its adaptation to cold habitats, some polyunsaturated fatty acids, such as stearidonic acid (18:4n-3), eicosatetraenoic acid (20:4n-3), and eicosapentaenoic acid (20:5n-3), are produced at a higher level at low temperature. The genome is 4,456kb in size and has a GC content of 41.12%. Uniquely, strain #4 possesses genes for sialic acid metabolism and utilizes N-acetyl neuraminic acid as a carbon source. Interestingly, it also encodes for cytochrome c3 genes, which are known to facilitate environmental adaptation, including elevated temperatures and exposure to UV radiation. Phylogenetic analysis based on a consensus sequence of the seven 16S rRNA genes indicated that strain #4 belongs to genus Shewanella, closely associated with Shewanella aestuarii with a ~97% similarity, but with a low DNA–DNA hybridization (DDH) level of ~21%. However, average nucleotide identity (ANI) analysis defines strain #4 as a separate Shewanella species (ANI score=76). Further phylogenetic analysis based on the 92 most conserved genes places Shewanella strain #4 into a distinct phylogenetic clade with other cold-active marine Shewanella species. Considering the phylogenetic, phenotypic, and molecular characterization, we conclude that Shewanella strain #4 is a novel species and name it Shewanella glacialimarina sp. nov. TZS-4T, where glacialimarina means sea ice. Consequently, S. glacialimarina TZS-4T constitutes a promising model for studying transcriptional and translational regulation of cold-active metabolism.

scholarly journals Antimicrobial Potential of Rhizospheric Bacteria Streptobacillus sp.

2021 ◽  
Author(s):  
Jay Kishor Prasad ◽  
Riddha Dey ◽  
Richa Raghuwanshi
Keyword(s):  
Pathogenic Bacteria ◽  
Antagonistic Activity ◽  
Diffusion Method ◽  
Disc Diffusion Method ◽  
Biochemical Tests ◽  
Good Source ◽  
Rhizospheric Bacteria ◽  
Wide Range ◽  
And Staphylococcus Aureus ◽  
Agar Well Diffusion Method

Rhizospheric bacteria exhibiting antagonistic effects are a good source for the production of antibiotics. The antibiotics produced are naturally bactericidal or bacteriostatic in nature. In the present investigation, thirty-five rhizospheric bacteria were isolated from different soil samples. Agar well diffusion method, streak agar method, disc diffusion method and biochemical tests were performed to screen the ten antibiotic-producing bacteria. Among them, strain JRR34 selected on the basis of primary antagonistic activity was identified as Streptobacillus sp. Media optimisation was done to ensure maximum production of secondary metabolites. Streptobacillus sp. JRR34 showed good inhibitory activity against Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus. The ethyl crude extract of Streptobacillus sp. JRR34 rhizobacteria possessing good antagonistic activity against a wide range of pathogenic bacteria can be a vital source of novel antibiotics.

scholarly journals Isolation of Probiotic Lactobacilli from Indigenous Yogurt and Cheese and Their Antagonistic Roles Against Foodborne Pathogens

2021 ◽  
Vol 22 (5) ◽  
Author(s):  
Elnaz Ahmadnejad ◽  
Samaneh Dolatabadi
Keyword(s):  
Human Health ◽  
Pathogenic Bacteria ◽  
Acid Tolerance ◽  
Microtiter Plate ◽  
Bacteriocin Production ◽  
Diffusion Method ◽  
Bile Salt Hydrolase ◽  
Human Pathogens ◽  
Organic Acid Production ◽  
Microtiter Plate Assay

Background: Probiotic bacteria are one of the useful dietary supplements for human health. The main reason for selecting probiotics is the lack of prolonged side effects. Objectives: This study aimed to isolate lactobacilli from traditional yogurt and cheese samples collected in Neyshabur city, Khorasan Razavi, Iran, and to characterize them using specific biochemical and molecular assays. Methods: The probiotic potency of bacteria was tested by resistance to acid, bile, NaCl, and organic acid production. Moreover, the antagonistic effects of the isolates were investigated against enteric pathogenic bacteria using the well diffusion method. Bacteriocin production was also investigated using the microtiter plate assay. Results: Four Lactobacillus spp. with > 99% homology to L. reuteri, L. plantarum, and L. acidophilus, were isolated with probiotic potency. The quantitative measurements used in the study with the statistical analysis resulted in the interpretation of good effects against Clostridium perfringens, Salmonella typhi, Staphylococcus aureus, and Listeria monocytogenes. Our isolates exhibited bile salt hydrolase activity, excellent NaCl and acid tolerance (pH = 3), and bacteriocin production. Conclusions: Our results showed that Lactobacillus strains isolated from Neyshabur traditional cheese could be considered good potential probiotic strains and had more antagonistic activity against human pathogens when compared to other samples. Their antibacterial activity was associated with both bacteriocin and organic acids production, but they should be further investigated for their human health benefits.

scholarly journals A Comparative Study: Taxonomic Grouping of Alkaline Protease Producing Bacilli

2017 ◽  
Vol 66 (1) ◽  
pp. 39-56
Author(s):  
Nilgun Tekin ◽  
Arzu Coleri Cihan ◽  
Basar Karaca ◽  
Cumhur Cokmus
Keyword(s):  
16S Rrna ◽  
Alkaline Protease ◽  
Phylogenetic Analyses ◽  
Molecular Techniques ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Protease Production ◽  
Rrna Gene ◽  
Wide Range ◽  
Its Pcr

Alkaline proteases have biotechnological importance due to their activity and stability at alkaline pH. 56 bacteria, capable of growing under alkaline conditions were isolated and their alkaline protease activities were carried out at different parameters to determine their optimum alkaline protease production conditions. Seven isolates were showed higher alkaline protease production capacity than the reference strains. The highest alkaline protease producing isolates (103125 U/g), E114 and C265, were identified as Bacillus licheniformis with 99.4% and Bacillus mojavensis 99.8% based on 16S rRNA gene sequence similarities, respectively. Interestingly, the isolates identified as Bacillus safensis were also found to be high alkaline protease producing strains. Genotypic characterizations of the isolates were also determined by using a wide range of molecular techniques (ARDRA, ITS-PCR, (GTG)5-PCR, BOX-PCR). These different techniques allowed us to differentiate the alkaliphilic isolates and the results were in concurrence with phylogenetic analyses of the 16S rRNA genes. While ITS-PCR provided the highest correlation with 16S rRNA groups, (GTG)5-PCR showed the highest differentiation at species and intra-species level. In this study, each of the biotechnologically valuable alkaline protease producing isolates was grouped into their taxonomic positions with multi-genotypic analyses.

scholarly journals Assessment of antibiotic- and disinfectant-resistant bacteria in hospital wastewater, south Ethiopia: a cross-sectional study

2015 ◽  
Vol 9 (02) ◽  
pp. 149-156 ◽  
Author(s):  
Sintayehu Fekadu ◽  
Yared Merid ◽  
Hunachew Beyene ◽  
Wondu Teshome ◽  
Solomon Gebre-Selassie
Keyword(s):  
Pathogenic Bacteria ◽  
Cross Sectional Study ◽  
Diffusion Method ◽  
Resistant Bacteria ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Hospital Wastewater ◽  
Sectional Study ◽  
Cross Sectional ◽  
Wide Range

Introduction: Large quantities of antimicrobials are used in hospitals for patient care and disinfection. Antibiotics are partially metabolized and residual quantities reach hospital wastewater, exposing bacteria to a wide range of biocides that could act as selective pressure for the development of resistance. Methodology: A cross-sectional study was conducted between December 2010 and February 2011 on hospital wastewater. A total of 24 composite samples were collected on a weekly basis for bacteriological analysis and susceptibility testing. Indicator organisms and pathogenic and potentially pathogenic bacteria were found and isolated on selective bacteriologic media. Disinfectant activity was evaluated by use-dilution, and minimum inhibitory concentration (MIC) was determined by the agar dilution method. Similarly, antibiotic susceptibility tests were performed using the Kirby-Bauer disk diffusion method. Results: Pathogenic (Salmonella, Shigella, and S. aureus) and potentially pathogenic (E. coli) bacteria were detected from effluents of both hospitals. Dilution demonstrated tincture iodine to be the most effective agent, followed by sodium hypochlorite; the least active was 70% ethanol. MIC for ethanol against S. aureus and Gram-negative rods from Yirgalem Hospital (YAH) showed 4 and 3.5 log reduction, respectively. Salmonella isolates from YAH effluent were resistant to ceftriaxone, tetracycline, and doxycycline. Isolates from Hawassa University Referral Hospital (HURH) effluent were resistant to the above three antibiotics as well as gentamycin. Conclusions: Hospital effluents tested contained antibiotic-resistant bacteria, which are released into receiving water bodies, resulting in a threat to public health.

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