scholarly journals SURVIVAL ASSESSMENT OF PATHOGENIC BACTERIA WITH ANTIBIOTIC RESISTANCE TRAITS FROM FRESH SUMMER ROYAL GRAPE: IN VITRO MICROBIAL CHALLENGE TEST

2020 ◽  
Vol 10 (3) ◽  
pp. 344-349
Author(s):  
Taslima Akter
Keyword(s):  
Antibiotic Resistance ◽  
Pathogenic Bacteria ◽  
Challenge Test ◽  
Microbial Challenge ◽  
Resistance Traits

scholarly journals Assessment of survival of pathogenic bacteria in fresh vegetables through in vitro challenge test

2015 ◽  
Vol 2 (1) ◽  
Author(s):  
Rashed Noor ◽  
Mushfia Malek ◽  
Shohanur Rahman ◽  
Monirunnessa Meghla ◽  
Mrityunjoy Acharjee ◽  
...  
Keyword(s):  
Pathogenic Bacteria ◽  
Challenge Test ◽  
Fresh Vegetables

scholarly journals Edible Seaweeds and Spirulina Extracts for Food Application: In Vitro and In Situ Evaluation of Antimicrobial Activity towards Foodborne Pathogenic Bacteria

Foods ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 1442 ◽  
Author(s):  
Francesco Martelli ◽  
Martina Cirlini ◽  
Camilla Lazzi ◽  
Erasmo Neviani ◽  
Valentina Bernini
Keyword(s):  
Antimicrobial Activity ◽  
Phenolic Compounds ◽  
Pathogenic Bacteria ◽  
Challenge Test ◽  
Algal Species ◽  
Total Phenolic ◽  
Salmonella Spp ◽  
Foodborne Pathogenic Bacteria

Research is more and more focused on studying and selecting food preservatives of natural origin. In this scenario, algae are an excellent source of bioactive compounds, among which are antimicrobials, whose presence is variable depending on the algal species and environmental conditions. The aim of the present study was to obtain, by a food grade approach, antimicrobial extracts from five species already approved as foods and to test their efficacy in vitro (agar well diffusion assay) and in situ (microbial challenge test) towards foodborne pathogenic bacteria. Moreover, the total phenolic compounds of the extracts were determined in order to evaluate possible correlations with the antimicrobial activity. Strains belonging to Salmonella spp., Listeria monocytogenes, Escherichia coli, Staphylococcus aureus, and Bacillus cereus were considered. Overall, the extracts showed a good antimicrobial activity in vitro towards all the tested microorganisms, especially L. monocytogenes (15 mm of inhibition diameter). The effect of inhibition was monitored during 24, 48 and 120 h showing a good persistence in time. Arthrospira platensis exerted the highest efficacy, further revealed towards L. monocytogenes on salmon tartare as bacteriostatic using 0.45% of the extract and bactericidal using 0.90%. The presence of phenolic compounds could be related to the antimicrobial activity but was not revealed as the main component of this activity. The extract with the highest phenolic content (18.79 ± 1.90 mg GAE/g) was obtained from Himanthalia elongata. The efficacy, confirmed also in a food matrix, might open perspectives for their application as food preservative.

scholarly journals Selection of lactic acid bacteria as a probiotic and evaluated its performance on gnotobiotic catfish Clarias sp.

2018 ◽  
Vol 17 (1) ◽  
pp. 68
Author(s):  
Enita Romasni Turnip ◽  
Widanarni, Widanarni ◽  
Anja Meryandini
Keyword(s):  
Growth Rate ◽  
Lactic Acid ◽  
Survival Rate ◽  
Lactic Acid Bacteria ◽  
Aeromonas Hydrophila ◽  
Pathogenic Bacteria ◽  
Challenge Test ◽  
Feed Conversion

<p class="JudulBabdenganNomor">ABSTRACT</p><p class="JudulBabdenganNomor"> </p><p>This study aimed to select lactic acid bacteria (LAB) as a potential probiotic that producing anti‒microbial compounds in order to treat motile aeromonads septicemia diseases caused by <em>Aeromonas hydrophila</em> on catfish <em>Clarias</em> sp. and evaluated its performance on gnotobiotic catfish. The <em>in vitro</em> assay was done to select several LAB isolates based on antagonistic activity against pathogenic bacteria. The selected isolate was tested <em>in vivo</em> to observe their ability to improve growth performances of catfish. The study was conducted with five treatments consists of K‒ (normal catfish without addition probiotic, without challenge test), K+ (normal catfish without addition of probiotic, with challenge test), Np (normal catfish with addition of probiotic and challenge test), G (gnoto catfish without addition of probiotic, with challenge test), and Gp (gnoto catfish with addition of probiotic and challenge test). The results showed that the addition of <em>Pediococcus pentosaceus</em> E2211 as selected probiotic could increase survival rate, specific growth rate, and immune response towards infection of <em>A. hydrophila</em>. The best survival rate after challenge test was obtained in Np and Gp treatments (88.46%), followed by G treatment (65.38%), while the K+ was only 53.84%. The conclusion of this study was <em>P. pentosaceus</em> E2211 potentially used as a probiotic candidate for normal and gnotobiotic catfish. The presence of normal microflora with <em>P. pentosaceus</em> E2211 in Np treatment showed the best probiotic performance with daily growth rate 3.28%, feed conversion ratio 1.79, and total intestinal bacteria reached 10<sup>8</sup> CFU/mL significantly different from other treatments (P&lt;0.05).</p><p>Keywords: <em>Aeromonas hydrophila,</em> catfish, LAB, probiotic, screening</p><p> </p><p> </p><p align="center"><strong>ABSTRAK</strong></p><p>Tujuan penelitian ini adalah menyeleksi bakteri asam laktat (BAL) sebagai probiotik potensial penghasil senyawa antimikrob guna menanggulangi penyakit <em>motile aeromonad septicemia</em> akibat <em>Aeromonas hydrophila</em> pada ikan lele <em>Clarias </em>sp. dan evaluasi kinerjanya pada ikan lele gnotobiotik. Pengujian <em>in vitro </em>dilakukan untuk menyeleksi beberapa isolat BAL sebagai kandidat probiotik berdasarkan aktivitas antagonis terhadap bakteri patogen. Isolat terpilih kemudian diuji <em>in vivo</em> untuk mengetahui kemampuannya dalam meningkatkan performa tumbuh ikan lele.<em> </em>Penelitian ini menggunakan rancangan acak lengkap dengan lima perlakuan, yaitu: K‒ (lele normal tanpa probiotik dan tanpa tanpa diuji tantang), K+ (lele normal tanpa probiotik dan diuji tantang), Np (lele normal diberi probiotik dan diuji tantang), G (lele gnoto tanpa probiotik dan diuji tantang), dan Gp (lele gnoto diberi probiotik dan diuji tantang). Hasil penelitian menunjukkan pemberian probiotik terpilih BAL <em>Pediococcus</em><em> pentosaceus</em> E2211 mampu meningkatkan sintasan, laju pertumbuhan, dan respons imun ikan lele terhadap infeksi <em>A. hydrophila</em>. Sintasan terbaik pascauji tantang diperoleh pada perlakuan Np dan Gp yaitu sebesar 88,46%, diikuti perlakuan G sebesar 65,38%, sementara pada K+ hanya mencapai 53,84%. Kesimpulan dari penelitian ini ialah isolat BAL terpilih <em>P. pentosaceus </em>E2211 berpotensi sebagai kandidat probiotik untuk ikan lele normal dan lele gnotobiotik <em>Clarias </em>sp. Keberadaan mikroflora normal yang berasosiasi dengan <em>P. pentosaceus </em>E2211 pada perlakuan Np menunjukkan kinerja probiotik terbaik dengan nilai laju pertubuhan harian 3,28%, rasio konversi pakan 1,79 dan total bakteri usus mencapai 10<sup>8</sup> CFU/mL yang berbeda signifikan dibanding perlakuan lainnya (P&lt;0,05).</p><p>Kata kunci: <em>A. hydrophila,</em> BAL, ikan lele, probiotik, seleksi</p><p> </p>

scholarly journals Antibiotic resistance modifying ability of phytoextracts in anthrax biological agent Bacillus anthracis and emerging superbugs: a review of synergistic mechanisms

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Mackingsley Kushan Dassanayake ◽  
Teng-Jin Khoo ◽  
Jia An
Keyword(s):  
Drug Resistance ◽  
Antibiotic Resistance ◽  
Bacillus Anthracis ◽  
Pathogenic Bacteria ◽  
Inhibitory Concentration ◽  
Epigallocatechin Gallate ◽  
Resistance Mechanisms ◽  
Synergistic Activity ◽  
Bacterial Drug Resistance

Abstract Background and objectives The chemotherapeutic management of infections has become challenging due to the global emergence of antibiotic resistant pathogenic bacteria. The recent expansion of studies on plant-derived natural products has lead to the discovery of a plethora of phytochemicals with the potential to combat bacterial drug resistance via various mechanisms of action. This review paper summarizes the primary antibiotic resistance mechanisms of bacteria and also discusses the antibiotic-potentiating ability of phytoextracts and various classes of isolated phytochemicals in reversing antibiotic resistance in anthrax agent Bacillus anthracis and emerging superbug bacteria. Methods Growth inhibitory indices and fractional inhibitory concentration index were applied to evaluate the in vitro synergistic activity of phytoextract-antibiotic combinations in general. Findings A number of studies have indicated that plant-derived natural compounds are capable of significantly reducing the minimum inhibitory concentration of standard antibiotics by altering drug-resistance mechanisms of B. anthracis and other superbug infection causing bacteria. Phytochemical compounds allicin, oleanolic acid, epigallocatechin gallate and curcumin and Jatropha curcas extracts were exceptional synergistic potentiators of various standard antibiotics. Conclusion Considering these facts, phytochemicals represents a valuable and novel source of bioactive compounds with potent antibiotic synergism to modulate bacterial drug-resistance.

Vibrio harveyi virulence gene expression in vitro and in vivo during infection in black tiger shrimp Penaeus monodon

2020 ◽  
Vol 139 ◽  
pp. 153-160
Author(s):  
S Peeralil ◽  
TC Joseph ◽  
V Murugadas ◽  
PG Akhilnath ◽  
VN Sreejith ◽  
...  
Keyword(s):  
Gene Expression ◽  
Virulence Genes ◽  
Vibrio Harveyi ◽  
Penaeus Monodon ◽  
Challenge Test ◽  
Virulence Gene ◽  
Economic Losses ◽  
Virulence Gene Expression

Luminescent Vibrio harveyi is common in sea and estuarine waters. It produces several virulence factors and negatively affects larval penaeid shrimp in hatcheries, resulting in severe economic losses to shrimp aquaculture. Although V. harveyi is an important pathogen of shrimp, its pathogenicity mechanisms have yet to be completely elucidated. In the present study, isolates of V. harveyi were isolated and characterized from diseased Penaeus monodon postlarvae from hatcheries in Kerala, India, from September to December 2016. All 23 tested isolates were positive for lipase, phospholipase, caseinase, gelatinase and chitinase activity, and 3 of the isolates (MFB32, MFB71 and MFB68) showed potential for significant biofilm formation. Based on the presence of virulence genes, the isolates of V. harveyi were grouped into 6 genotypes, predominated by vhpA+ flaB+ ser+ vhh1- luxR+ vopD- vcrD+ vscN-. One isolate from each genotype was randomly selected for in vivo virulence experiments, and the LD50 ranged from 1.7 ± 0.5 × 103 to 4.1 ± 0.1 × 105 CFU ml-1. The expression of genes during the infection in postlarvae was high in 2 of the isolates (MFB12 and MFB32), consistent with the result of the challenge test. However, in MFB19, even though all genes tested were present, their expression level was very low and likely contributed to its lack of virulence. Because of the significant variation in gene expression, the presence of virulence genes alone cannot be used as a marker for pathogenicity of V. harveyi.

Sources and mechanisms of combined heavy-metal and antibiotic resistance traits in bacteria

2017 ◽  
Vol 62 (1) ◽  
pp. 101-114 ◽  
Author(s):  
Claudia Tugui ◽  
◽  
Edina Szekeres ◽  
Andreea Baricz ◽  
◽  
...  
Keyword(s):  
Heavy Metal ◽  
Antibiotic Resistance ◽  
Resistance Traits

Preliminary in Vitro Investigations on The Inhibitory Activity of The Original Dietary Supplement Oxidal® on Pathogenic Bacterial Strains

2020 ◽  
Vol 11 ◽  
pp. 37-43
Author(s):  
Prof. Teodora P. Popova ◽  
Toshka Petrova ◽  
Ignat Ignatov ◽  
Stoil Karadzhov
Keyword(s):  
Dietary Supplement ◽  
Broad Spectrum ◽  
Pathogenic Bacteria ◽  
Antimicrobial Agents ◽  
Clinical Effectiveness ◽  
Inhibitory Effect ◽  
Diffusion Method ◽  
Bacterial Strains ◽  
Microbial Strains

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.

THE ACTIVITY OF ESSENTIAL OILS OBTAINED FROM SPECIES AND INTERSPECIES HYBRIDS OF THE Mentha GENUS AGAINST SELECTED PLANT PATHOGENIC BACTERIA

2018 ◽  
Vol 17 (6) ◽  
pp. 167-174 ◽  
Author(s):  
Małgorzata Schollenberger ◽  
Tomasz M. Staniek ◽  
Elżbieta Paduch-Cichal ◽  
Beata Dasiewicz ◽  
Agnieszka Gadomska-Gajadhur ◽  
...  
Keyword(s):  
Essential Oils ◽  
Pseudomonas Syringae ◽  
Pathogenic Bacteria ◽  
Antimicrobial Effect ◽  
Mentha Piperita ◽  
Mentha Spicata ◽  
Plant Essential Oils ◽  
Plant Pathogenic Bacteria ◽  
Interspecies Hybrids

Plant essential oils of six aromatic herb species and interspecies hybrids of the family Lamiaceae – chocolate mint (Mentha piperita × ‘Chocolate’), pineapple mint (Mentha suaveolens ‘Variegata’), apple mint (Mentha × rotundifolia), spearmint (Mentha spicata), orange mint (Mentha × piperita ‘Granada’) and strawberry mint (Mentha × villosa ‘Strawberry’) – were investigated for antimicrobial effects against plant pathogenic bacteria: Agrobacterium tumefaciens, Pseudomonas syringae pv. syringae and Xanthomonas arboricola pv. corylina. The screening was carried out in vitro on agar plates filled with the target organism. All essential oils screened exhibited a higher level of antibacterial activity against A. tumefaciens and X. arboricola pv. corylina than streptomycin used as a standard in all tests. The antimicrobial effect of streptomycin and five mint oils was at the same level for P. syringae pv. syringae. There were no significant differences in the influence of the chocolate mint oil on the growth inhibition of all bacteria tested. Plant essential oils from pineapple mint, apple mint, spearmint and strawberry mint showed the weakest antimicrobial activity against P. syringae pv. syringae and the strongest towards A. tumefaciens and X. arboricola pv. corylina. The essential oils from strawberry mint, pineapple mint, spearmint and apple mint had the strongest effect on A. tumefaciens, and the lowest inhibitory activity was exhibited by the chocolate mint and orange mint essential oils. X. arboricola pv. corylina was the most sensitive to the strawberry mint, pineapple mint and spearmint oils. The chocolate mint oil showed the greatest activity against P. syringae pv. syringae.

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