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

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.

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Evaluation of the Role of Staphylococci in the Pathomechanism of Conjunctivitis

10.21203/rs.3.rs-191872/v1 ◽

2021 ◽

Author(s):

Ewa Jasińska ◽

Agnieszka Bogut ◽

Agnieszka Magryś ◽

Alina Olender

Keyword(s):

Antibiotic Resistance ◽

Epithelial Cells ◽

Biofilm Formation ◽

Methicillin Resistance ◽

Microtiter Plate ◽

Host Cells ◽

Diffusion Method ◽

Microtiter Plate Assay ◽

Low Prevalence

Abstract Purpose: Determination of the association between ica genes and phenotypic biofilm formation in staphylococcal isolates involved in conjunctivitis, their antibiotic resistance as well as detection of selected virulence characteristics: adhesion to epithelial cells and in vitro cytotoxicity.Methods: The study included 26 Staphylococcus aureus (SA) and 26 Staphylococcus epidermidis (SE) isolates. The presence of icaAD genes and ica operon was determined by the PCR assay. Phenotypic biofilm formation was verified using the microtiter plate assay. Antibiotic resistance was performed using the disc diffusion method. Staphylococcal ability to attach to host cells was assessed by flow cytometry. Cytotoxicity on epithelial cells was evaluated by LDH assay.Results: The ica genes were detected in 26.9% of SE and in 42.3% of SA isolates. Only 15.3% of isolates (SE) were positive for both the icaAD and the ica operon. Phenotypically, 19.2% of SE isolates were strong biofilm producers, among which three were both icaAD- and ica operon-positive. 26.9% of SA isolates were strong biofilm producers. Methicillin resistance (MR) was detected in 34.6% of SE and 26.9% of SA isolates. 75% of MR isolates were multidrug resistant. SA isolates adhered to host cells more extensively than SE. SA isolates released higher level of LDH than SE.Conclusions: Adherence abilities were commonly observed in staphylococci associated with conjunctivitis. However, low prevalence of isolates positive for a complete and functional ica locus and low prevalence of strong biofilm producers was detected. SA adhered to a greater extent to eukaryotic cells than SE and were more cytotoxic.

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INVESTIGATION OF THE SYNERGISTIC ANTIBACTERIAL ACTION OF COPPER NANOPARTICLES ON CERTAIN ANTIBIOTICS AGAINST HUMAN PATHOGENS

International Journal of Pharmacy and Pharmaceutical Sciences ◽

10.22159/ijpps.2018v10i10.28069 ◽

2018 ◽

Vol 10 (10) ◽

pp. 83

Author(s):

Selvarani Murugan

Keyword(s):

Antibacterial Activity ◽

Copper Nanoparticles ◽

Pathogenic Bacteria ◽

Color Change ◽

Quantitative Information ◽

Inorganic Nanoparticles ◽

Diffusion Method ◽

Human Pathogens ◽

Bacterial Strains ◽

Agar Disc

Objective: Resistance to antibacterial agents by pathogenic bacteria has emerged in recent years and is a major challenge for the healthcare industry. Copper nanoparticles (CuNPs) are known to be one of the multifunctional inorganic nanoparticles with effective antibacterial activity. Hence the present investigation has been focused on synthesizing and evaluating the bactericidal effect of copper nanoparticles.Methods: CuNPs were synthesized by reducing the aqueous solution of copper sulfate with sodium borohydride. The synthesized particles were characterized by x-ray diffractogram (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) techniques to analyze size, morphology and quantitative information respectively. The antibacterial activity of CuNPs was examined by agar well diffusion method. Synergistic effect of CuNPs with broad-spectrum antibiotics was determined by the agar disc diffusion method.Results: Color change of reaction mixture from blue to dark brown indicated the formation of CuNPs. SEM image clearly demonstrated that the synthesized particles were spherical in shape and its size was found to be 17.85 nm. EDS report confirmed the presence of elemental copper in the resultant nanoparticles and its accounts for major proportion (96%) of the mass of nanoparticles. Bacterial effect of CuNPs revealed that Pseudomonas aeruginosa showed the highest antibacterial sensitivity (16.00±1.63 mm), whereas least susceptibility (9.67±0.47 mm) was noticed against Staphylococcus aureus. An enhanced antibacterial activity of commercial antibiotics was also noticed when it combined with CuNPS. A minimum zone of inhibition was increased from 0.67±0.47 mm to 10.66±0.24 mm when the nanoparticles and antibiotics were given together.Conclusion: It was observed that copper nanoparticles exhibited profound activity against all the tested bacterial strains which shows that CuNPs may serve as a better option for use in medicine in the future.

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GC-MS Analysis and Antimicrobial Assessment of Syzygium cumini (L.) Skeels Seed Ethanol Extract

Journal of Pharmaceutical Research International ◽

10.9734/jpri/2021/v33i56b33953 ◽

2021 ◽

pp. 271-283

Author(s):

S. Mabel Parimala ◽

A. Antilin Salomi

Keyword(s):

Bacterial Species ◽

Ethanol Extract ◽

Microtiter Plate ◽

Salmonella Typhi ◽

Fungal Species ◽

Gas Chromatography Mass Spectrometry ◽

Diffusion Method ◽

Syzygium Cumini ◽

Microtiter Plate Assay ◽

Agar Well Diffusion Method

People use plants to treat infections, and this has led to search of antimicrobials from medicinal plants. In this work, we evaluated the ethanol extract of Syzygium cumini seeds for their antibacterial and antifungal activities. Extraction was performed by maceration method using ethanol. The antimicrobial efficacy of the extract was assessed by agar well diffusion method against ten bacterial species, Bacillus cereus, Bacillus subtilis, Enterococcus faecalis, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella typhi, Serratia marcescens, Staphylococcus aureus and Streptococcus mutans, and five fungal species, Aspergillus flavus, Aspergillus fumigatus, Aspergillus niger, Candida albicans and Mucor sp. Minimum inhibitory concentrations (MICs) of the extract were determined by resazurin microtiter plate assay. Phytochemicals in the extract was identified by gas chromatography mass spectrometry (GC-MS) information. In agar well diffusion method, Gram-negative bacteria such as P. aeruginosa and S. marcescens, Gram-positive bacteria such as B. subtilis and E. faecalis and fungi A. fumigatus were more susceptible showing larger zones of inhibition. In resazurin method, low MICs were recorded for bacteria, B. cereus (<7.8 µg) and P. aeruginosa (15.6 µg) and fungi, A. fumigatus (31.2 µg). Fifteen compounds were identified by GC-MS profiling of the extract. The antimicrobial activity of the extract can be rightly related to the secondary metabolites in the ethanol extract of Syzygium cumini seeds.

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Isolation and Identification of Antibiotic-Producing Halophilic Bacteria from Dagh Biarjmand and Haj Aligholi Salt Deserts, Iran

Pharmaceutical Sciences ◽

10.15171/ps.2019.11 ◽

2019 ◽

Vol 25 (1) ◽

pp. 70-77 ◽

Cited By ~ 1

Author(s):

Babak Elyasifar ◽

Sevda Jafari ◽

Somayeh Hallaj-Nezhadi ◽

Florence Chapeland-leclerc ◽

Gwenaël Ruprich-Robert ◽

...

Keyword(s):

Pathogenic Bacteria ◽

Plant Pathogens ◽

Halophilic Bacteria ◽

Pathogenic Fungi ◽

Antibacterial Activities ◽

Biochemical Properties ◽

Diffusion Method ◽

Human Pathogens ◽

Isolation And Identification ◽

Phylogenic Tree

Background: Halophilic bacteria are potent organisms in production of novel bioactive antimicrobial compounds which might be considered in drug innovation and control of plant pathogens. Salt deserts in Semnan province are of the most permanent hypersaline areas in the North of Iran. Despite the importance of these areas, there is no scientific report regarding the biodiversity and potency of their halophilic bacteria. Thus, aforementioned areas were selected to detect the halophilic bacteria. Methods: Here, seven strains were isolated and cultured on their molecular and biochemical properties were characterized. To determine the antibiotic potency of the isolates, agar well diffusion method was conducted. Phylogenetic analysis was done to reveal the isolates relationship with previously known strains. Results: As a result, growth of the strains in the medium containing 5 to 20% (w/v) NaCl determined that the majority of the isolates were moderately halophile. Catalase activity of all strains was positive. The results represented that D6A, Dar and D8B have antimicrobial effects against different plant and human pathogens. Phylogenic tree analysis also showed that two strains of D6A and Dar are belonged to Bacillus subtilis and D8B is belonged to Virgibacillus olivae. The bacteria extracts were evaluated for their antifungal and antibacterial activities on human and Plant pathogenic strains. The MIC of the extract B. subtilis against was found active against human pathogenic fungi and Plant pathogenic bacteria and fungi, ranging from 12.5 to 25 µg/mL. Conclusion: This study highlights the therapeutic and prophylactic potential of B. subtilis extracts as antibacterial and antifungal agents.

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Antimicrobial activity of Commercial essential oils on human pathogens

Research Journal of Pharmacy and Technology ◽

10.52711/0974-360x.2021.00771 ◽

2021 ◽

pp. 4440-4444

Author(s):

B. R. Malathy ◽

Sweetlin Ajitha P ◽

Sangeetha K. S ◽

Swetha Thampy ◽

Kamala G

Keyword(s):

Antimicrobial Activity ◽

Essential Oils ◽

Pathogenic Bacteria ◽

Steam Distillation ◽

Diffusion Method ◽

Human Pathogens ◽

Aromatic Plants ◽

Zone Of Inhibition ◽

E Coli ◽

Development Of Resistance

Essential oils (EOs) are natural extracts from the seeds, stems, roots, flowers, bark and other parts of the plant prepared by steam distillation. They are complex, volatile, natural compounds formed by aromatic plants as secondary metabolites. They are known for their bactericidal, virucidal, fungicidal, sedative, anti-inflammatory, analgesic, spasmolytic and locally anesthetic properties. They are generally composed of a combination of substances like terpenes, phenolics, aldehydes or alcohols. The complex composition and different mechanisms of action of EOs may be an advantage over other antimicrobials to prevent the development of resistance of pathogenic bacteria. With this background, the aim of this study was to evaluate the antimicrobial activity of five essential oils like basil, lime, rosemary, thyme and canada balsam against 14 microbes. The effects of essential oil on the selected microbes were determined by agar well diffusion method. The zone of inhibition was observed and measured in millimeter. Essential oils which showed inhibitory diameter >15 mm were further tested to determine the minimum inhibitory concentration (MIC). S. aureus, E. coli, S. mutans, S. sanguinis, C. albicans and M. furfur were inhibited by all essential oils. K. pneumoniae, P. aeruginosa and E .faecalis were inhibited only by thyme and not by other essential oils. The MIC values ranged from 50% to 0.10%. The least MIC value of 0.10% was shown by thyme and basil to S. aureus, thyme to E.coli and all essential oils against C. albicans except lime.

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Biocide's susceptibility and frequency of biocide resistance genes and the effect of exposure to sub-inhibitory concentrations of sodium hypochlorite on antibiotic susceptibility of Stenotrophomonas maltophilia

10.1101/2021.10.04.463145 ◽

2021 ◽

Author(s):

Safar Ali Alizadeh ◽

Amir Javadi ◽

Farhad Nikkhahi ◽

Mohammad Rostamani ◽

Mehdi Bakht ◽

...

Keyword(s):

Sodium Hypochlorite ◽

Resistance Genes ◽

Antibiotic Susceptibility ◽

Inhibitory Concentration ◽

Microtiter Plate ◽

Multidrug Resistant ◽

Diffusion Method ◽

Dilution Method ◽

Disk Diffusion Method ◽

Microtiter Plate Assay

Background: The overused of biocides in healthcare-facilities poses risk for emergence and spread of antibiotic resistance among nosocomial pathogens. Hospital-acquired infections due to S. maltophilia particularly in the immunocompromised patients have been increased. The objective of this study was to evaluate the susceptibility of S. maltophilia clinical isolates to commonly used biocides in hospitals, as well the frequency of biocides resistance gene among them. This study also intended to assess the effect of exposure of S. maltophilia isolates to sub-inhibitory concentrations of sodium hypochlorite upon the antimicrobial susceptibility patterns. Methods: This study included 97 S. maltophilia isolates. Biofilm formation was determined by microtiter plate assay. The susceptibility tests of five biocides were studied against all S. maltophilia isolates by microbroth dilution method. Susceptibility of isolates to antibiotics by disk diffusion method were compared before and after exposure to sub-inhibitory concentrations of sodium hypochlorite. Presence of qacE, qacEΔ1, SugE genes was screened by PCR. Results: Based on minimum inhibitory and bactericidal concentrations of biocides sodium hypochlorite 5% and ethyl alcohol 70% were the strongest and weakest against S. maltophilia isolates, respectively. The frequency of sugE gene resistance genes was found to be high (90.7%) in our clinical S. maltophilia isolates. None of the isolates carried qacE and qacEΔ1 gene. Exposure to sub-inhibitory concentration of sodium hypochlorite showed significantly change the susceptibility of isolates towards ceftazidime (P = .019), ticarcillin/clavulanate (P = .009). and chloramphenicol (P = .028). Conclusions: This study demonstrated that exposure to sub-inhibitory concentration of sodium hypochlorite leads to reduced antibiotic susceptibility and development of multidrug-resistant S. maltophilia strains.

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ANTIBACTERIAL AND ANTIBIOFILM ACTIVITY OF QUERCUS INFECTORIA GALLS ON ROTHIA DENTOCARIOSA ISOLATED FROM DENTAL CARIES

Asian Journal of Pharmaceutical and Clinical Research ◽

10.22159/ajpcr.2019.v12i10.34725 ◽

2019 ◽

pp. 159-162

Author(s):

AMBULKAR S ◽

TALE V ◽

KHILARI S ◽

PAWAR J

Keyword(s):

Dental Caries ◽

16S Rrna ◽

Microtiter Plate ◽

Diffusion Method ◽

Antibiofilm Activity ◽

Phytochemical Analysis ◽

16S Rrna Sequence ◽

Biofilm Inhibition ◽

Microtiter Plate Assay ◽

Quercus Infectoria

Objective: The present study aimed to study Quercus infectoria gall extract for phytochemical analysis, antibacterial, and antibiofilm activity against Rothia dentocariosa isolated from dental caries. Methods: R. dentocariosa was isolated, characterized, and identified by 16S rRNA sequence and also checked for biofilm formation ability. Phytochemical analysis of Q. infectoria aqueous gall extracts was carried out. Antibacterial and antibiofilm activity was performed using agar well diffusion method and microtiter plate assay, respectively. Results: Bacterial isolate from dental caries was identified as R. dentocariosa by 16s rRNA sequencing technique with accession number MH824681 obtained from NCBI. Phytochemical analysis of Q. infectoria aqueous gall extract revealed the presence of alkaloids, phenol, tannin, glycosides, phenolic compound, and flavonoids. Significant antibacterial activity was observed with 19.00 (±7.07) mm diameter zone of inhibition. The biofilm inhibition assay was performed by microtiter plate method indicated 92.89% inhibition of bacteria at the concentration of 100 mg/mL of aqueous extract. Conclusion: The results indicated the efficacy of Q. infectoria gall extracts that could be explored as an alternative to current treatment.

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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

Journal of Food Research ◽

10.5539/jfr.v2n1p50 ◽

2013 ◽

Vol 2 (1) ◽

pp. 50 ◽

Cited By ~ 4

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 Bacillus cereus PA24, Escherichia coli SKN 541, Enterococcus faecalis 103907 CIP, Staphylococcus aureus ATCC 19095 and Listeria monocytogenes Scott A, using the agar well diffusion method. Bacteriocins of Lactobacillus reuteri 2-20B and Pediococcus acidilactici 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 Lb. reuteri and Pd. acidilactici strains exhibited the widest inhibitory activities whereas CFS of Lb. fermentum exhibited the least inhibitory activity towards the tested pathogens. Bacteriocins of Lb. reuteri 2-20B and Pd. acidilactici 0-11A retained their antibacterial activities over a wide range of pH. Whereas the antimicrobial activity of Lb. reuteri 2-20B was lost after being subjected to temperature of 90°C for 1 h, CFS of Pd. acidilactici 0-11A remained stable after autoclaving at 121°C for 15 min. Again, the antimicrobial activities of both Lb. reuteri 2-20B and Pd. acidilactici 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 Lb. reuteri 2-20B and Pd. acidilactici 0-11A were growth associated and influeced by media composition.

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Antibacterial and anti-hemolytic activity of tannins from Pimenta dioica against methicillin resistant Staphylococcus aureus

Bangladesh Journal of Pharmacology ◽

10.3329/bjp.v12i1.29735 ◽

2017 ◽

Vol 12 (1) ◽

pp. 63

Author(s):

Reham Al-Harbi ◽

Razan Al-wegaisi ◽

Fatma Moharram ◽

Mona Ibrahem Shaaban ◽

Ola Abd El-Rahman

Keyword(s):

Staphylococcus Aureus ◽

Microtiter Plate ◽

High Rate ◽

Assay Method ◽

Diffusion Method ◽

Microtiter Plate Assay ◽

Methicillin Resistant ◽

New Antibiotics ◽

Pimenta Dioica

High rate of resistance among Staphylococcus infection initiates scientists to discover new antibiotics. The objective of this study is to determine the effect of tannins isolated from the Pimenta dioica leaves on Staphylococcus aureus and methicillin resistant S. aureus as well as to evaluate their effect on hemolysin production. The antimicrobial activity of 4,6-(S)-hexahydroxydiphenoyl-(α/β)-D-glucopyranose and casuarinin, pedunculagin and nilocitin tannins from P. dioica was examined using agar diffusion method. Moreover, minimum inhibitory concentrations were evaluated by microtiter plate assay method. Pedunculagin and nilocitin exhibited antibacterial and anti-hemolytic effect against S. aureus. This will open the era for in vivo assessment of such compounds for clinical applications.

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Strain-Specific Transfer of Antibiotic Resistance from an Environmental Plasmid to Foodborne Pathogens

Journal of Biomedicine and Biotechnology ◽

10.1155/2012/834598 ◽

2012 ◽

Vol 2012 ◽

pp. 1-8 ◽

Cited By ~ 18

Author(s):

Eva Van Meervenne ◽

Els Van Coillie ◽

Frederiek-Maarten Kerckhof ◽

Frank Devlieghere ◽

Lieve Herman ◽

...

Keyword(s):

Flow Cytometry ◽

Antibiotic Resistance ◽

Human Health ◽

Resistance Genes ◽

Foodborne Pathogens ◽

Pathogenic Bacteria ◽

Treatment Plant ◽

Diffusion Method ◽

Broad Host Range ◽

Transfer Ratio

Pathogens resistant to multiple antibiotics are rapidly emerging, entailing important consequences for human health. This study investigated if the broad-host-range multiresistance plasmid pB10, isolated from a wastewater treatment plant, harbouring amoxicillin, streptomycin, sulfonamide, and tetracycline resistance genes, was transferable to the foodborne pathogensSalmonellaspp. orE. coliO157:H7 and how this transfer alters the phenotype of the recipients. The transfer ratio was determined by both plating and flow cytometry. Antibiotic resistance profiles were determined for both recipients and transconjugants using the disk diffusion method. For 14 of the 15 recipient strains, transconjugants were detected. Based on plating, transfer ratios were between6.8×10−9and3.0×10−2while using flow cytometry, transfer ratios were between <1.0×10−5and1.9×10−2. With a few exceptions, the transconjugants showed phenotypically increased resistance, indicating that most of the transferred resistance genes were expressed. In summary, we showed that an environmental plasmid can be transferred into foodborne pathogenic bacteria at high transfer ratios. However, the transfer ratio seemed to be recipient strain dependent. Moreover, the newly acquired resistance genes could turn antibiotic susceptible strains into resistant ones, paving the way to compromise human health.

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