A decrease in therapeutic effect of some live lacto- and bifdobacteria-based drugs for veterinary use has been observed for the last 20 years that urges scientists to search for new microorganisms possessing probiotic properties. Many studies in this feld are focused onBacillus subtilisthat is widespread in the environment and non-pathogenic for animals and humans. Results of tests ofBacillus subtilisfor its biological properties and antagonistic activity aimed at optimization of methodical approaches for detection of strain with the highest antagonistic effect on some opportunistic microorganisms and their further use as probiotics are described. Cultural morphological and biochemical characteristics of the tested strains conformed to the species characteristics ofBacillus subtilis.Tested strains were nonpathogenic for white mice. Tests showed that spore biomass could be prepared both in liquid and on solid nutrient media. Methodically, spore biomass preparation in liquid nutrient medium is preferable. The tests showed that spores emerged from anabiosis non-uniformly and it depended on original seed spore storage period. Spore cultures stored less than one year emerged from anabiosis more quickly. It was found that the spores formed more readily when the cultures were aerated with oxygen as well as that lag-phase culture medium had a stimulating effect onBacillus subtilisspore germination.Bacillus subtilisstrains were found to have antagonistic effect onEscherichia coli, SalmonellaandStaphylococcus. Area of growth inhibition of the said bacteria was 15–20 mm. TestedBacillus subtilisstrains could be proposed for use as probiotics.
Upward trend in the number of human yersiniosis cases, caused by bacterium Yersinia enterocolitica, is globally observed nowadays. This microorganism is widely spread in the environment, able to persist for prolonged periods in animal products and propagate under low temperatures. Basic infection sources are meat and meat products. In order to isolate Yersinia enterocolitica from food and feed samples horizontal method for the detection pursuant to GOST ISO 10273-2013 was used. It was noted, that Yersinia enterocolitica isolation is associated with certain difficulties, because the sample contains only small quantities of the agent and only the use of special techniques allows removing the concurrent microflora. It was proposed to use cold enrichment (4 ± 1) °C of the test material before conventional technique is started. The technique was validated pursuant to GOST ISO 16140-2011. As a result, it was established that validated method for Yersinia enterocolitica bacteria detection in food products, performed at the Microbiology Laboratory, is specific. The method sensitivity is 10 CFU/cm3. Intralaboratory reproducibility and repeatability were confirmed by relevant tests. Additional culture step at (4 ± 1) °C allows complete inhibition of non-psychrophilic microorganisms’ growth.
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Иммуногенные свойства изолятов и штаммов Avibacterium paragallinarum серогруппы В РЕЗЮМЕ Инфекционное заболевание кур, вызываемое бактерией Avibacterium рaragallinarum, остается одной из актуальных проблем птицеводческой отрасли, о чем говорят многочисленные сообщения о периодических вспышках инфекционного ринита кур в разных странах мира. Проведенные с 2014 по 2019 г. бактериологические исследования показали, что Российская Федерация эндемична по данному заболеванию, вызываемому Avibacterium paragallinarum серогруппы В. Представлены результаты исследования по изучению иммуногенных свойств антигенов 13 изолятов возбудителя инфекционного ринита кур, выделенных из патологического материала, доставленного в ФГБУ «ВНИИЗЖ» с птицефабрик Российской Федерации и Республики Беларусь. Для этого готовили образцы вакцины, содержащей в своем составе инактивированные формалином клетки Avibacterium рaragallinarum и масляный адъювант. Птиц иммунизировали с последующим контрольным заражением гомологичными и гетерологичными изолятами. Степень проявления клинических признаков заболевания оценивали по методике, предложенной V. E. Soriano. Образец вакцины на основе антигена изолята АрВ08 индуцировал недостаточный иммунный ответ у птиц при инфицировании изолятами АрВ04 и АрВ12. В свою очередь, при заражении изолятом АрВ08 был показан высокий уровень защиты животных. Изоляты АрВ04, АрВ08 и АрВ12 были всесторонне изучены, определены как наиболее перспективные для производства вакцины против инфекционного ринита кур и депонированы в Государственную коллекцию штаммов микроорганизмов ФГБУ «ВНИИЗЖ» под номерами 1116, 5111 и 1818 соответственно. Также была проведена сравнительная оценка иммуногенной активности экспериментальной вакцины против инфекционного ринита кур, включающей антигены штаммов № 1116, 5111 и 1818, с двумя коммерческими препаратами. Экспериментальный препарат показал максимальный процент защиты птиц при заражении гомологичными штаммами Avibacterium рaragallinarum.Ключевые слова: инфекционный ринит кур, изоляты, штаммы, вакцина, контрольное заражение, Avibacterium paragallinarum.Благодарность: Работа выполнена за счет средств ФГБУ «ВНИИЗЖ» в рамках тематики научно-исследовательских работ «Ветеринарное благополучие».
Bacteria of Campylobacter genus are ones of the main zoonotic pathogens causing human and animal diseases. Campylobacter organisms are microaerophiles and, therefore, require low oxygen concentration (3–5%) and high carbon dioxide concentration (3–10%) for their growth. They use amino acids rather than carbons as a source of energy. Classical bacteriological methods for Campylobacter spp. detection are not always successful due to diffi culties in creating optimal conditions for their growth. Therewith, development and implementation of molecular methods for Campylobacter detection and identifi cation are of current importance. Assay for qualitative Campylobacter spp. detection with real-time polymerase chain reaction using CFX-96 thermocycler was optimized. Highly specifi c segment of 16S rRNA gene allowing identifi cation of 6 Campylobacter species: C. jejuni, C. coli, C. lari, C. upsaliensis, C. helveticus и C. hyointestinalis was selected as an amplifi cation target. Optimal magnesium ion concentration (2.5 мМ) and primer annealing temperature (58 °С) were determined. Eighteen reference strains of various bacteria were tested. Only tests of Campylobacter genus strains gave positive results. The method sensitivity was 40 target molecules. The said method was used for testing 76 samples of raw materials of animal origin. Campylobacter spp. genome was detected in 18 samples. Obtained results showed that the optimized variant of real-time polymerase chain reaction based on 16S rRNA gene amplifi cation was a specifi c, sensitive, rapid, reproducible and accurate method for qualitative detection of Campylobacter spp. in samples of raw animal materials.
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