scholarly journals Searching for Antagonistic Activity of Bacterial Isolates Derived from Food Processing Environments on Some Food-Borne Pathogenic Bacteria

2020 ◽  
Vol 49 (4) ◽  
pp. 415-423
Author(s):  
B. Baráti-Deák ◽  
Cs. Mohácsi-Farkas ◽  
Á. Belák

Bacterial strains with inhibitory effect on Salmonella Hartford, Listeria monocytogenes, Yersinia enterocolitica, and Escherichia coli, respectively, were isolated. Out of the 64 bacteria originated from food processing environments, 20 could inhibit at least one of the tested pathogens, and it was proved that growth decline of the pathogenic bacteria was more remarkable by co-culturing than by using cell-free supernatants of the isolates. Seven different genera (Pseudomonas, Bacillus, Paenibacillus, Macrococcus, Staphylococcus, Serratia, and Rothia) reduced the pathogens’ growth during the time period of analysis, and the strongest inhibitory effect was observed after 24 h between 15 and 30 °C. Sensitivity of the tested human pathogenic bacteria against the inhibitory strains was distinct, as Y. enterocolitica could be inhibited by numerous isolates, while S. Hartford proved to be the most resistant. Our results reveal that the isolated bacteria or their excreted metabolites could hinder pathogen growth when used in sufficient quantities.

2009 ◽  
Vol 6 (4) ◽  
pp. 627-632
Author(s):  
Baghdad Science Journal

In this part of programme , different bacterial isolates mainly Salmonella spp, Shigella spp and Escherichia coli were used for antagonism with Saccharomyces boulardii under different conditions . S.boulardii was grown under aerobic conditions and antagonized with young overnight nutrient broth cultures of test bacterial isolates and other kept in refrigerator for a week after full growth . Young cultures were more susceptible to antagonistic effect of yeast compared to old cultures and on isolates grown on solid medium for 24 hr. S.boulardii grown under aerobic and microaerobic conditions and antagonized with overnight broth cultures of test bacterial isolates , The results revealed that aerobic cultures of yeast had more inhibitory effect on test isolates .Concentration of yeast cells from liquid media GS( prepared from soluble fraction of gluten and mixed with equal volume of corn steep water and GS2%) was found not to be exceeded 109 yeast cell/ ml of suspension due to the large size of yeast cells .Effect of freezing on viability of yeast cells grown in GS and GS2% was negligible and there was no significant differences since the difference was less then half log cycle


2017 ◽  
Vol 1 (2) ◽  
Author(s):  
Mukesh Pimpliskar ◽  
Priyanka Pagare ◽  
Rahul Jadhav

Antagonistic activity of marine bacteria against common human pathogens was studied in this project. Marine animal surface bacterial flora was isolated from selected animal collected from local fishermen. The sample bacteria were isolated by serial dilution followed by spread plate method using marine agar (ZMA). About 11 bacterial isolates were selected and screened for antimicrobial activity through agar well diffusion assay. Among 11 isolates, 7 isolates exerted an inhibitory effect against human pathogenic organisms (E.coli, S.aureus, Klebsiella and Candida sp.). The isolates were then investigated for antibiotic production by cross species signal transfer mediated induction, 2 isolates (Sh-2 and PJR-3) exhibited enhanced activity against human pathogenic organisms (E.coli, S.aureus and Candida sp.). These 2 isolates were characterized phenotypically by morphological techniques (which revealed the strains as gram-positive and gram negative respectively) and physiologically by conventional tests. 


2021 ◽  
Author(s):  
B. Baráti-Deák ◽  
Á. Belák ◽  
Cs. Mohácsi-Farkas

AbstractPreviously isolated Pseudomonas lundensis CP-P-5 had antagonistic activity against Salmonella Hartford, Yersinia enterocolitica, and Escherichia coli. In this study, determination of its antagonistic mechanism and potential field of application in food industry was aimed. Using cellophane-test and microcultures of the test strain's cell-free supernatant mixed with the pathogens, our results showed that cells of P. lundensis CP-P-5 and its concentrated cell-free supernatants were effective against the foodborne bacteria, and the supernatants contained more than one compound responsible for inhibitory activity. Searching for the antagonistic compound, NaOH, protease, and heat treatments were done to the supernatants, and proteolytic activity and siderophore production were also tested using the antagonistic strain. Our results support the potential applicability of P. lundensis CP-P-5 as a bioprotective agent against foodborne pathogens in food processing environments.


2021 ◽  
Vol 4 (2) ◽  
pp. 11-16
Author(s):  
A.H. Jauro ◽  
I. Shu’aibu ◽  
G. Lawan ◽  
M.T. Adamu ◽  
M.Y. Iliyasu ◽  
...  

The development of biofilms by the foodborne pathogens attached to surfaces in the food processing environments results in the deterioration of products, persistence of pathogenic bacteria and transmission of food-associated diseases. In addition, biofilms are more resistant to antimicrobials than their planktonic counterparts which make their elimination from food and the food processing facilities a great challenge. This study aim was to determine the inhibitory effect of food additives on biofilm forming Escherichia coli O157:H7. The isolate obtained was subjected to Gram’s staining and various biochemical identifications and later confirmed by latex agglutination test. Biofilm formation potential was done on Congo red media and the confirmed biofilm former was subjected to biofilm formation at 10℃ and 37℃ for 168hrs. Antimicrobial susceptibility testing, MIC, MBC, and antibiofilm effect was determined following CLSI 2017 guideline. The highest zone of growth inhibition of 31 mm was exhibited by cinnamaldehyde, sodium nitrite with 26 mm and sodium citrate with 13 mm. The MIC 2.5 mg/mL was recorded for sodium citrate, 0.25 mg/mL for sodium nitrite and 0.125 μl/mL for cinnamaldehyde. Strong biofilm was formed at 37 ℃ with 7.82 x 109 CFU/mL viable cells at 168hrs while 6.79 x 109 CFU/mL were obtained at 10 ℃. All the three additives showed antibiofilm effect (at 10℃ and 37℃), cinnamaldehyde exhibited 70%-90.1%, sodium nitrite; 70%-88.2% inhibition and sodium nitrite; 75%-88% inhibition respectively. This study showed that sodium citrate, sodium nitrite and cinnamaldehyde exerted strong antimicrobial and antibiofilm properties indicating their potential as good preservatives.


2020 ◽  
Vol 11 ◽  
pp. 37-43
Author(s):  
Prof. Teodora P. Popova ◽  
Toshka Petrova ◽  
Ignat Ignatov ◽  
Stoil Karadzhov

The antimicrobial action of the dietary supplement Oxidal® was tested using the classic Bauer and Kirby agar-gel diffusion method. Clinical and reference strains of Staphylococcus aureus and Escherichia coli were used in the studies. The tested dietary supplement showed a well-pronounced inhibitory effect against the microbial strains commensurable with that of the broad-spectrum chemotherapeutic agent Enrofloxacin and showed even higher activity than the broad spectrum antibiotic Thiamphenicol. The proven inhibitory effect of the tested dietary supplement against the examined pathogenic bacteria is in accordance with the established clinical effectiveness standards for antimicrobial agents.


Author(s):  
Kai Chen ◽  
Biao Ma ◽  
Jiali Li ◽  
Erjing Chen ◽  
Ying Xu ◽  
...  

Food-borne pathogens have become an important public threat to human health. There are many kinds of pathogenic bacteria in food consumed daily. A rapid and sensitive testing method for multiple food-borne pathogens is essential. Europium nanoparticles (EuNPs) are used as fluorescent probes in lateral flow immunoassays (LFIAs) to improve sensitivity. Here, recombinase polymerase amplification (RPA) combined with fluorescent LFIA was established for the simultaneous and quantitative detection of Listeria monocytogenes, Vibrio parahaemolyticus, and Escherichia coliO157:H7. In this work, the entire experimental process could be completed in 20 min at 37 °C. The limits of detection (LODs) of EuNP-based LFIA–RPA were 9.0 colony-forming units (CFU)/mL for Listeria monocytogenes, 7.0 CFU/mL for Vibrio parahaemolyticus, and 4.0 CFU/mL for Escherichia coliO157:H7. No cross-reaction could be observed in 22 bacterial strains. The fluorescent LFIA–RPA assay exhibits high sensitivity and good specificity. Moreover, the average recovery of the three food-borne pathogens spiked in food samples was 90.9–114.2%. The experiments indicate the accuracy and reliability of the multiple fluorescent test strips. Our developed EuNP-based LFIA–RPA assay is a promising analytical tool for the rapid and simultaneous detection of multiple low concentrations of food-borne pathogens.


2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Olufunmiso O. Olajuyigbe ◽  
Roger M. Coopoosamy

Background.This study was aimed at evaluating the antibacterial activity of the acetone extract ofA. mearnsiiand its interactions with antibiotics against some resistant bacterial strains.Methods.The antibacterial susceptibility testing was determined by agar diffusion and macrobroth dilution methods while the checkerboard method was used for the determination of synergy between the antibiotics and the extract.Results.The results showed that the susceptibility of the different bacterial isolates was concentration dependent for the extract and the different antibiotics. With the exception ofS. marcescens, the inhibition zones of the extract produced by 20 mg/mL ranged between 18 and 32 mm. While metronidazole did not inhibit any of the bacterial isolates, all the antibiotics and their combinations, except for ciprofloxacin and its combination, did not inhibitEnterococcus faecalis. The antibacterial combinations were more of being antagonistic than of being synergistic in the agar diffusion assay. From the macrobroth dilution, the extract and the antibiotics exerted a varied degree of inhibitory effect on the test organisms. The MIC values of the acetone extract which are in mg/mL are lower than those of the different antibiotics which are inμg/mL. From the checkerboard assay, the antibacterial combinations showed varied degrees of interactions including synergism, additive, indifference, and antagonism interactions. While antagonistic and additive interactions were 14.44%, indifference interaction was 22.22% and synergistic interaction was 37.78% of the antibacterial combinations against the test isolates. While the additivity/indifference interactions indicated no interactions, the antagonistic interaction may be considered as a negative interaction that could result in toxicity and suboptimal bioactivity.Conclusion.The synergistic effects of the herbal-drug combinations may be harnessed for the discovery and development of more rational evidence-based drug combinations with optimized efficiency in the prevention of multidrug resistance and therapy of multifactorial diseases.


It is a great concern that extended-spectrum β-lactamase (ESBL) and non-ESBL uropathogenic micro-organisms have been worldwide illustrated to increase multidrug resistance. To study the prevalence and patterns of uropathogens, and antimicrobial susceptibilities profiles of ESBL and non-ESBL producing bacterial infection in a tertiary level health service center of Bangladesh. The prevalence of ESBL producing uropathogens and their antimicrobial resistance patterns were identified in 176 isolates from patients with UTI. ESBL and non-ESBL producing bacterial isolates and their antibiotic sensitivity and resistance patterns were distinguished from the 176 patients of suspected urinary tract infection. The Double-disc diffusion test was done to determine the presence of ESBL-producing bacterial strains. The most widely ESBL positive uropathogen was Escherichia coli (87%), followed by Pseudomonas aeruginosa, (6.8%), Enterococcus spp. (3.4%), Acinetobacter spp. (2.5%) and non-ESBL positive E. coli (41.4), Staphylococcus saprophyticus (25.9%), Pseudomonas aeruginosa (17.2%), Staphylococcus aureus (10.3%), and Klebsiella pneumoniae (5.2%). The current investigation found most frequently Escherichia coli in both ESBL and non-ESBL uropathogenic groups as 87% and 41.4% respectively. Generally, a large number of antibiotic resistance patterns and ESBL producing common bacterial isolates were found in this study which increases the public health problem. Therefore, for safe human life, we ought to be taking appropriate action against the threat.


2015 ◽  
Vol 68 (2) ◽  
pp. 7721-7727
Author(s):  
Piedad M. Montero Castillo ◽  
Antonio Díaz Caballero ◽  
Marlene Durán Lengua

In the food industry, food preservation techniques that do not use chemical products are becoming more common. Therefore, the aim of this research was to evaluate the antagonistic activity (antibiosis) of lactic-acid bacterial strains against pathogenic microorganisms. Lactic-acid bacterial strains were isolated from layered cheese and a commercial product (yogurt); and the same was done with pathogenic bacteria solely from layered cheese. The lactic-acid bacterial strains were identified as species from the Lactobacilli family, while the pathogenic bacteria from layered cheese were identified as Micrococcaceae family species (Staphylococcus aureus). Subsequently, in the same culture medium, bacteria of each species were sowed in order to determine the inhibitory activity ability of the Lactic Acid Bacteria (BAL) As a result, the highly antagonistic activity of the Lactobacilli (inhibition halos were larger than 0.5 centimeters in diameter) against isolated pathogenic microorganisms was demonstrated.


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