scholarly journals Phenotypic and Genotypic Characteristics of Enterocin Producing Enterococci against Pathogenic Bacteria

2015 ◽  
Vol 38 (2) ◽  
pp. 209-216 ◽  
Author(s):  
Sandra Mojsova ◽  
Kiril Krstevski ◽  
Igor Dzadzovski ◽  
Zagorka Popova ◽  
Pavle Sekulovski
Keyword(s):  
Antimicrobial Activity ◽  
Pathogenic Bacteria ◽  
Structural Genes ◽  
E Coli ◽  
Technological Potential ◽  
Cheese Industry ◽  
Pcr Method ◽  
Enterocin A ◽  
Genotypic Characteristics ◽  
Enterocin P

AbstractThe study investigated the antimicrobial activity of 13 enterococcal strains (E. faecalis -8, E. faecium-2, E. hirae-2, E. spp.-1) isolated from our traditional cheeses against pathogen microorganisms. Also, it includes the detection of the following enterocin structural genes: enterocin A, enterocin B, enterocin P, enterocin L50A/B, bacteriocin 31, enterocin AS48, enterocin Q, enterocin EJ97 and cytolysin by using PCR method. All isolates inhibited growth of L. monocytogenes and L.innocua. One isolate had a broader antimicrobial activity. None of the isolates showed inhibitory activity against S. enteritidis, E. coli and Y. enterocolitica. The genes enterocin P, cytolysin and enterocin A were the most frequently detected structural genes among the PCR positive strains. No amplification was obtained in two strains E. faecalis-25 and E. faecalis-86. Three different genes were identified in some strains. With the exclusion of strains possessing a virulence factor, such as cytolysin, producers of more than one enterocins could be of a great technological potential as protective cultures in the cheese industry.

Prevalence of bacteriocin activities and bacteriocin-encoding genes in enterococcal clinical isolates in Iran

2012 ◽  
Vol 58 (4) ◽  
pp. 359-368 ◽  
Author(s):  
Maryam Hassan ◽  
Dzung B. Diep ◽  
Yousef Javadzadeh ◽  
Siavash Dastmalchi ◽  
Ingolf F. Nes ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Clinical Isolates ◽  
Proteinase K ◽  
Structural Genes ◽  
High Antimicrobial Activity ◽  
Antimicrobial Substances ◽  
Genes Encoding ◽  
Pcr Method ◽  
Enterocin A ◽  
Bacteriocin Genes

The aim of the project was to isolate and characterize bacteriocin-producing enterococci, as well as determine the prevalence of enterocin structural genes in 187 enterococcal clinical isolates from the northwest of Iran. The isolates were screened for antibacterial activity against 15 different indicator strains. The proteinaceous nature of the antimicrobial substances was confirmed by sensitivity to proteinase K; their stability to heat treatment was tested at 60 °C and 100 °C for 20 and 10 min, respectively. The PCR method was applied to detect previously identified enterocin genes. Our results showed that 38 (20.3%) of the enterococcal isolates were considered to be potential bacteriocinogenic strains. Furthermore, genes encoding diverse bacteriocin are highly distributed among clinical enterococci, and the strains with multi-bacteriocin genes displayed high antimicrobial activity. Enterocin A, enterolysin A, and enterocin L50A/B were the most abundant structural genes detected in bacteriocinogenic strains. This work is the first survey on the prevalence of bacteriocin genes among clinical enterococci in Iran that has isolated a strain with high antimicrobial activity and sensitivity to clinically relevant antibiotics.

scholarly journals The Assessment of antimicrobial activity of cerumen (earwax) and antibiotics against pathogenic bacteria isolated from ear pus samples

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Iffat Naz
Keyword(s):  
Antimicrobial Activity ◽  
Antibacterial Activity ◽  
Pathogenic Bacteria ◽  
Maximum Activity ◽  
Prevalence Data ◽  
Culture Techniques ◽  
E Coli ◽  
Pseudomonas Spp ◽  
Test Organisms ◽  
Staphylococcus Spp

The present study is focused on the assessment of the antimicrobial activity of cerumen and antibiotics against bacteria isolated from ear pus samples. Thus, a total of 50 ear pus samples were collected from infected patients using sterile swabs and were screened using pure culture techniques. Total of 04 different bacterial isolates were identified while, the prevalence data revealed that Pseudomonas spp., were dominant (58%, n = 29) among isolated bacteria followed by Staphylococcus spp., (22%, n = 11), Escherichia coli (14%, n = 7) and Proteus spp., (6%, n = 3). Further, bioassay revealed that Pseudomonas spp., and Staphylococcus spp., were most sensitive to Clindamycin (94.73%) while displayed resistant to Ciprofloxacin and Ampicillin. Similarly, E. coli and Proteus spp., were most sensitive to Ciprofloxacin (92.8-95.21%) as compared to the other antibiotics. Moreover, antibacterial activity of cerumen was also assessed against test organisms and its maximum activity was observed against Pseudomonas spp., (90% equivalent to Clindamycin potency) and Staphylococcus spp., (60% equivalent to Amoxicillin potency) while least effective against E. coli (36%) and Proteus spp., (22%). Thus, it was concluded that the antibacterial activity of cerumen might be due to the presence of potential chemicals i.e. flavonoids and terpenoids.

scholarly journals Antimicrobial effects of fruit sauces on some pathogenic bacteria in vitro and on chicken breast meat

2021 ◽  
Vol 72 (1) ◽  
pp. 2703
Author(s):  
I VAR ◽  
S UZUNLU ◽  
I DEĞIRMENCI
Keyword(s):  
Antimicrobial Activity ◽  
Pathogenic Bacteria ◽  
Diffusion Method ◽  
Chicken Breast ◽  
Type I ◽  
Antimicrobial Effects ◽  
E Coli ◽  
Agar Diffusion

The use of natural food additives is currently a rising trend. In the present study, the aim was to determine the antimicrobial effects of plum, pomegranate, Seville orange and sumac sauces on E. coli O157:H7,E. coli type I,Listeriamonocytogenes, Listeria ivanovii, Salmonella Typhimurium and Staphylococcus aureus. Different concentrations (1%, 10%, 100%, v/v) of the sauces were tested on the studied bacteria in vitro using the agar diffusion and minimal inhibition concentration (MIC) methods. The results showed that the sumac sauce had the highest antimicrobial activity. The Seville orange, plum and pomegranate sauces also exerted antimicrobial activity in descending order. The antimicrobial activity of the fruit sauces was more effective at a concentration of 100% than at 10% and 1%, v/v. The most inhibitory effect was recorded for sumac sauce at a concentration of 100% (v/v) on L.monocytogenesand E. coli O157:H7. The findings of the MIC method aligned with the agar diffusion method. In addition, the in situ(food method) antimicrobial effect of the sauces on the indigenous microflora of chicken breast samples sold in stores was determined. Chicken samples hosting aerobic mesophilic bacteria, coliforms and E. coli were treated for two hours at 4 °C with plum, pomegranate, Seville orange and sumac sauces and were then monitored. The findings revealed that the Seville orange and sumac sauces were the most effective in reducing the indigenous microbial growth on the chicken samples. The plum sauce showed higher antimicrobial activity than pomegranate sauce. The phenolic content and acidity of the samples significantly (P< 0.05) affected the antimicrobial activity both in vitro (agar diffusion and MIC) and in situ (chilled chicken breast). In conclusion, the sumac and Seville orange sauces were found to be the most promising natural antibacterial agents, and their use could be recommended, for example, in catering services to reduce the risk of foodborne illness.

Antimicrobial activity of Commercial essential oils on human pathogens

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.

scholarly journals Increasing the Shelf Life of Milk by Metal Oxide Nanoparticles and Mild Heat

2020 ◽  
Author(s):  
Mahbooubeh Mirhosseini ◽  
Roghayeh Dehestani
Keyword(s):  
Electron Microscopy ◽  
Antimicrobial Activity ◽  
Metal Oxide ◽  
Pathogenic Bacteria ◽  
Morphological Changes ◽  
Synergistic Effects ◽  
Metal Oxide Nanoparticles ◽  
Oxide Nanoparticles ◽  
E Coli ◽  
Mild Heat

Background: The spread of pathogenic microorganisms in food and beverage and their resistance to antibiotics have raised major concerns for public health. The aim of this study was to investigate the antimicrobial activity of various metal oxide nanoparticles (NPs) including zinc oxide (ZnO), magnesium oxide (MgO), and iron oxide (Fe2O3) NPs against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). Furthermore, the antimicrobial activity of these NPs in milk was studied along with mild heat. Methods: In this experimental study, the antibacterial activity of ZnO, MgO, and Fe2O3 NPs were initially evaluated by minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) methods. Later, the antimicrobial effect of these NPs was investigated in milk along with mild heating. To determine the morphological changes in S. aureus and E. coli, electron microscopy scanning was applied before and after the antimicrobial treatments. Results: The MBC and MIC values presented by Fe2O3, ZnO, and MgO NPs against pathogenic bacteria showed that MgO NPs were the most potent substances for inhibiting the growth of S. aureus and E. coli. The results also indicated that use of these NPs had synergistic effects in combination with the heating treatment. Electron microscopy scanning also revealed that treatment with MgO NPs could distort and impair the cell wall of the pathogenic bacteria, leading to the leakage of intracellular components and bacterial death. Conclusion: The results suggest that MgO, ZnO, and Fe2O3 NPs can be applied for industrial food processing as effective antimicrobial compounds to decrease the temperature required for pasteurizing milk.

scholarly journals Killer Activity of Hanseniaspora uvarum Isolated from Dates Vinegar: Partially Purification and Characterization of Killer Toxin

2019 ◽  
Vol 16 (1(Suppl.)) ◽  
pp. 0140
Author(s):  
Hameed Et al.
Keyword(s):  
Antimicrobial Activity ◽  
Pathogenic Bacteria ◽  
Plant Pathogens ◽  
Killer Toxin ◽  
Toxin Production ◽  
Antagonistic Activity ◽  
Killer Activity ◽  
E Coli ◽  
Killer Yeast ◽  
Hanseniaspora Uvarum

This study was conducted to isolate and identify killer yeast Hanseniaspora uvarum from dates vinegar and measurement the ability of this yeast to produce killer toxin. The antimicrobial activity of the concentrated supernatant containing partially purified concentrated killer toxin was also detected against several pathogenic bacteria and yeast species, which includes two types of yeast Rhodotorula mucilaginosa and Candida tropicalis and four human pathogenic bacteria Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeurginosa. In addition, the antagonistic activity of examined yeast have been studied toward four types of fungi, where two are pathogenic for human Trichophyton mentagrophytes and Trichophyton rubrum and two are plant pathogens Fusarium solani and Sclerotinia sclerotiorum. The results of killer toxin production experiments revealed the ability of yeast to produce killer toxin with molecular weight at 18 kDa by 12 % SDS electrophoresis. The optimal conditions for killer toxin production were studied, and their antimicrobial activity was determined. The results revealed that killer toxin production was increased at 4 % NaCl, the highest inhibtion zone was 20 mm for S. aureus, while the lowest inhibition zone was 7 mm for E. coli. Killer activity was increased at pH 4 and the best inhibtion zone obtained was about 16 mm for K. pneumoniae, while 8 mm for E. coli and C. tropicalis. The temperature was also affect the production of killer toxin, where 25 °C is the best temperature for toxin production of examined yeast, The best killer activity was 21 mm for C. tropicalis. The antagonistic activity of killer yeast H. uvarum toward pathogenic fungal growth was determined and showed killer activity about 61.11, 44.44, 33.33 and 24.44 % against T. mentagrophytes, T.  rubrum, F. solani and S. sclerotiorum in comparison to the control.

scholarly journals AKTIVITAS ANTIMIKROBA BAKTERI ASAM LAKTAT YANG DIISOLASI DARI MAKANAN TRADISIONAL FERMENTASI KHAS BATAK “NANIURA”

2019 ◽  
Vol 6 (1) ◽  
pp. 8
Author(s):  
Aloysius Aloysius ◽  
Anjurniza Ulfa ◽  
Anggita Kasih Fianti Situmorang ◽  
Harmileni Harmileni ◽  
Edy Fachrial
Keyword(s):  
Antimicrobial Activity ◽  
Pathogenic Bacteria ◽  
Inhibition Zone ◽  
Fermented Food ◽  
Diffusion Method ◽  
Disc Diffusion ◽  
Disc Diffusion Method ◽  
E Coli ◽  
Gram Staining ◽  
Potential Source

Lactic acid bacteria (LAB) could be isolated from various fermented food products. One potential source of LAB is traditional fermented food. The aim of the study was to isolate and investigate antimicrobial activity of LAB isolated from traditional Batak food, “naniura”. The LAB isolates were characterized by Gram staining, fermentation type and catalase test. The investigation of antimicrobial activity of LAB against pathogenic bacteria were conducted using disc diffusion method. The results showed that 6 isolates of BAL were successfully isolated namely BN1, BN2, BN3, BN4, BN5 and BN6 had characteristics of Gram positive, rod shaped and catalase negative. All selected isolate have heterofermentation type. Four isolates (BN1, BN2, BN5 and BN6) were able to inhibit S. aureus, E. coli and S. typhi with inhibition zone diameters ranging from 6,9 to 12,3 cm. Based on the result, it was concluded that LAB isolated from naniura has potential as a source of probiotics.

scholarly journals Killer Activity of Hanseniaspora uvarum Isolated from Dates Vinegar: Partially Purification and Characterization of Killer Toxin

2019 ◽  
Vol 16 (1) ◽  
pp. 0140
Author(s):  
Hameed Et al.
Keyword(s):  
Antimicrobial Activity ◽  
Pathogenic Bacteria ◽  
Plant Pathogens ◽  
Killer Toxin ◽  
Toxin Production ◽  
Antagonistic Activity ◽  
Killer Activity ◽  
E Coli ◽  
Killer Yeast ◽  
Hanseniaspora Uvarum

This study was conducted to isolate and identify killer yeast Hanseniaspora uvarum from dates vinegar and measurement the ability of this yeast to produce killer toxin. The antimicrobial activity of the concentrated supernatant containing partially purified concentrated killer toxin was also detected against several pathogenic bacteria and yeast species, which includes two types of yeast Rhodotorula mucilaginosa and Candida tropicalis and four human pathogenic bacteria Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeurginosa. In addition, the antagonistic activity of examined yeast have been studied toward four types of fungi, where two are pathogenic for human Trichophyton mentagrophytes and Trichophyton rubrum and two are plant pathogens Fusarium solani and Sclerotinia sclerotiorum. The results of killer toxin production experiments revealed the ability of yeast to produce killer toxin with molecular weight at 18 kDa by 12 % SDS electrophoresis. The optimal conditions for killer toxin production were studied, and their antimicrobial activity was determined. The results revealed that killer toxin production was increased at 4 % NaCl, the highest inhibtion zone was 20 mm for S. aureus, while the lowest inhibition zone was 7 mm for E. coli. Killer activity was increased at pH 4 and the best inhibtion zone obtained was about 16 mm for K. pneumoniae, while 8 mm for E. coli and C. tropicalis. The temperature was also affect the production of killer toxin, where 25 °C is the best temperature for toxin production of examined yeast, The best killer activity was 21 mm for C. tropicalis. The antagonistic activity of killer yeast H. uvarum toward pathogenic fungal growth was determined and showed killer activity about 61.11, 44.44, 33.33 and 24.44 % against T. mentagrophytes, T.  rubrum, F. solani and S. sclerotiorum in comparison to the control.

scholarly journals Phenotypic and Genotypic Characterization of ESBL-, AmpC-, and Carbapenemase-Producing Klebsiella pneumoniae and Escherichia coli Isolates

2019 ◽  
Vol 28 (6) ◽  
pp. 547-551 ◽  
Author(s):  
Hossein Kazemian ◽  
Hamid Heidari ◽  
Roya Ghanavati ◽  
Sobhan Ghafourian ◽  
Fateme Yazdani ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Klebsiella Pneumoniae ◽  
Antimicrobial Agents ◽  
Drug Resistant ◽  
E Coli ◽  
Molecular Tests ◽  
Pcr Method ◽  
Hospital Acquired ◽  
Genotypic Characteristics

Objectives: Drug resistance among gram-negative bacteria is a worldwide challenge. Due to the importance of drug-resistant Klebsiella pneumoniae and Escherichia coli strains in hospital-acquired infections, we aimed to determine the phenotypic and genotypic characteristics of ESBL-, AmpC-, and carbapenemase-producing isolates obtained from hospitalized patients in Tehran and Ilam (Iran). Materials and Methods: In total, 90 K. pneumoniae isolates and 65 E. coli isolates were collected from various infections. Phenotypic identification of bacterial isolates was performed using standard methods. Phenotypic screening of ESBL, AmpC, and carbapenemase enzymes was carried out. Detection of ESBL, AmpC, and carbapenemase genes was also performed by the PCR method. Results: Phenotypic detection tests showed that 36 (40%) K. pneumoniae and 23 (35.4%) E. coli isolates were ESBL producers. Moreover, 18 (20%) and 6 (9.2%) K. pneumoniae and E. coli isolates were AmpC producers, respectively. Modified Hodge test results indicated that 39 (43.3%) K. pneumoniae and 18 (27.7%) E. coli isolates produced carbapenemase. Molecular tests showed that 40% of K. pneumoniae and 36.9% of E. coli isolates were ESBL positive. AmpC was detected in 24.4 and 13.8% of K. pneumoniae and E. coli isolates. Carbapenemase was detected in 34 (37.8%) K. pneumoniae and 13 (20%) E. coli isolates. ­Conclusion: In this study, 3 K. pneumoniae isolates simultaneously carried ESBL, AmpC, and carbapenemase genes. Up-to-date strategies such as combination therapy or utilization of new antimicrobial agents might help to combat such drug-resistant organisms.

scholarly journals Antimicrobial Activity of Selected Essential Oils against Selected Pathogenic Bacteria: In Vitro Study

Antibiotics ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 546
Author(s):  
Nikola Puvača ◽  
Jovana Milenković ◽  
Tamara Galonja Galonja Coghill ◽  
Vojislava Bursić ◽  
Aleksandra Petrović ◽  
...  
Keyword(s):  
Gas Chromatography ◽  
Antimicrobial Activity ◽  
Essential Oil ◽  
Essential Oils ◽  
Pathogenic Bacteria ◽  
Antimicrobial Properties ◽  
In Vitro Study ◽  
Tea Tree ◽  
E Coli

The worldwide problem of infectious diseases has appeared in recent years, and antimicrobial agents are crucial in reducing disease emergence. Nevertheless, the development and distribution of multidrug-resistant (MDR) strains in pathogenic bacteria, such as Escherichia coli, Staphylococcus aureus, Salmonella Typhi and Citrobacter koseri, has become a major society health hazard. Essential oils could serve as a promising tool as a natural drug in fighting the problem with these bacteria. The current study aimed to investigate the antimicrobial effectiveness of tea tree (Melaleuca alternifolia (Maiden and Betche) Cheel), rosemary (Rosmarinus officinalis L.), eucalyptus (Eucalyptus obliqua L’Hér.), and lavender (Lavandula angustifolia Mill) essential oils. The antimicrobial properties of essential oils were screened against four pathogenic bacteria, E. coli, S. aureus, S. Tyhpi, and C. koseri, and two reference bacterial strains, while for the testing, the agar well diffusion method was used. Gas chromatography (GC) and gas chromatography–mass spectrometric (GC–MSD) analyses were performed on essential oils. The obtained results showed that M. alternifolia essential oil is the richest in terpinen-4-ol, R. officinalis and E. oblique essential oils in 1,8-cineole, and L. angustifolia essential oil in α-terpinyl acetate. In addition, the main bioactive compounds present in the essential oil of tea tree are rich in α-pinene (18.38%), limonene (7.55%) and γ-terpinene (14.01%). The essential oil of rosemary is rich in α-pinene (8.38%) and limonene (11.86%); eucalyptus essential oil has significant concentrations of α-pinene (12.60%), p-cymene (3.24%), limonene (3.87%), and γ-terpinene (7.37%), while the essential oil of lavender is rich in linalool (10.71%), linalool acetate (9.60%), α-terpinyl acetate (10.93%), and carbitol (13.05%) bioactive compounds, respectively. The obtained results from the in vitro study revealed that most of the essential oils exhibited antimicrobial properties. Among the tested essential oils, tea tree was discovered to demonstrate the strongest antimicrobial activity. The recorded MIC of S. Typhi was 6.2 mg/mL, 3.4 mg/mL of C. koseri, 3.1 mg/mL of E. coli, and 2.7 mg/mL of E. Coli ATCC 25922, compared to M. alternifolia. Similarly, only S. aureus ATCC 25923 showed antimicrobial activity towards R. officinalis (1.4 mg/mL), E. oblique (2.9 mg/mL), and L. angustifolia (2.1 mg/mL). Based on the obtained results, it is possible to conclude that tea tree essential oil might be used as an ecological antimicrobial in treating infectious diseases caused by the tested pathogens.

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