scholarly journals STUDYING THE INFLUENCE OF HIGH-INTENSITY PULSE OPTICAL UV RADIATION OF A XENON LAMP ON PURE CULTURES OF MICROORGANISMS

Author(s):  
В.Ю. ГРЕЧНИКОВА ◽  
И.А. КОНДАКОВА ◽  
Д.В. ГРИГОРЕНКО

Проблема и цель. Целью данного исследования послужило теоретическое и практическое обоснование влияния высокоинтенсивного импульсного оптического УФ-излучения ксеноновой лампы на чистые культуры микроорганизмов – Escherichia coli, Staphylococcus aureus, Salmonella typhimurium, Proteus vulgaris, Klebsiella pneumonia, Hafnia alvei, а также изучение их чувствительности. Методология. Для достижения поставленной цели было проведено исследование с применением импульсной ксеноновой лампы прибора «Заря-1», основанное на использовании высокоинтенсивного импульсного оптического излучения сплошного спектра, генерируемого мощными высокотемпературными плазменными источниками. Проведены исследования бактерицидного действия различного количества импульсов излучения ксеноновой лампы на чистые культуры микроорганизмов. Эффективность воздействия УФ-излучения ксеноновой лампы оценивали путем подсчета количества выросших колоний микроорганизмов на агаризированных питательных средах в опытных и контрольных чашках Петри через 24 часа после их облучения и последующего выдерживания в термостате при температуре t=37 °C. Проведены анализы и сравнение полученного бактерицидного эффекта, обусловленного действием излучения с различными по количеству импульсами, в отношении изучаемых микроорганизмов, причем каждая из культур обладает неодинаковой чувствительностью к ультрафиолетовому излучению. Результаты. По результатам проведенной работы выявлена бактерицидная эффективность одного из вариантов излучения, что определяет исследуемый метод физической дезинфекции, как высоко результативный, опережающий по безопасности и эффективности химический метод и имеющий большие перспективы использования в животноводстве с целью обеззараживания воздуха животноводческих помещений. Заключение. Полученные результаты делают необходимым определение бактерицидного действия УФ-излучения импульсной ксеноновой лампы в отношении других видов микроорганизмов. Problem and purpose. The purpose of this study was the theoretical and practical substantiation of the efect of high-intensity pulsed optical UV radiation of a xenon lamp on pure cultures of microorganisms - Escherichia coli, Staphylococcus aureus, Salmonella typhimurium, Proteus vulgaris, Klebsiella pneumonia, Hafnia alvei, as well as the study of their sensitivity. Methodology. To achieve this purpose, a study was carried out using a pulsed xenon lamp of Zarya-1 device, based on the use of high-intensity pulsed optical radiation of a continuous spectrum, generated by powerful high-temperature plasma sources. There were studies of the bactericidal action of various numbers of xenon lamp radiation pulses on pure cultures of microorganisms. The efectiveness of exposure to UV radiation from a xenon lamp was assessed by counting the number of grown colonies of microorganisms on agar nutrient media in experimental and control Petri dishes 24 hours after their irradiation and subsequent incubation in a thermostat at a temperature of 37° C. Analyzes and comparisons of the obtained bactericidal efect caused by the action of radiation with pulses of diferent number in relation to the studied microorganisms were carried out. Each of the cultures had an unequal sensitivity to ultraviolet radiation. Results. Based on the results of the work carried out, the bactericidal efectiveness of one of the radiation options was revealed, which determines the studied method of physical disinfection as a highly efective chemical method that is ahead in safety and efciency, and has great prospects for animal husbandry when disinfecting the air of livestock buildings. Conclusion. The results obtained make it necessary to determine the bactericidal efect of UV radiation from a pulsed xenon lamp in relation to other types of microorganisms.

2011 ◽  
Vol 6 (6) ◽  
pp. 1934578X1100600 ◽  
Author(s):  
Angel Konakchiev ◽  
Milka Todorova ◽  
Bozhanka Mikhova ◽  
Antonina Vitkova ◽  
Hristo Najdenski

The essential oil of Achillea distans W. et K. flower heads was analyzed by GC and GC-MS. Altogether 43 components in concentrations more than 0.1% were identified representing 93.5% of the oil composition. The main constituents were 1,8-cineole (16.8%), trans-thujone (9.8%), sabinene (8.2%), borneol (7.5%), β-pinene (6.5%), and camphor (5.8%). The oil showed moderate activity against Staphylococcus aureus and Candida albicans, and weak activity against Salmonella typhimurium, Proteus vulgaris, and Escherichia coli.


Author(s):  
Famubo, Joseph A. ◽  
Isiaka, Aishatu ◽  
Abbas, Yusuf B.

The hygiene status of most abattoirs and retail outlets in Nigeria is very poor, and it contributes to the unacceptable level of bacteria load in beef, and poses a health risk to consumers. This study examined the bacteriological analysis of beef production chain in Birnin Kebbi metropolis. A total of 100 samples of meat, water and surface swab in Main Market, GRA, Badariya, Bayan Kara and Rafin Atiku, Birnin Kebbi Central abattoir and retail meat shops were collected aseptically, processed and analyzed. Meat from retail outlets were mostly contaminated by Staphylococcus aureus (24.4%), followed by Escherichia coli (17.3%), Klebsiella pneumonia (9.8%), Salmonella typhimurium (9.1%), Entrobater aerogenes (8.5%), Streptococcus pyogenes (8.1%), Proteus vulgaris (7.8%), Micrococcus luteus (7.8%) and Pseudomonas aeruginosa (7.2%). In the abattoirs contact surfaces, contamination occurred mostly by Staphylococcus aureus (23.4%), Salmonella typhimurium (18.2%), Escherichia coli (16.9%), Entrobater aerogenes (9.1%), Streptococcus pyogenes (7.8%), Klebsiella pneumonia, Proteus vulgaris, and Pseudomonas aeruginosa (6.5% each) and Micrococcus luteus (5.2%). The findings revealed a high bacterial load in both abattoir and retail meat outlets. In order to safeguard the health of the public against the risks of food borne infections, there is a need to educate and advocate good sanitation and meat handling practices in the abattoir and beef retail outlets.


2011 ◽  
Vol 8 (3) ◽  
pp. 1456-1461 ◽  
Author(s):  
Donatus Ebere Okwu ◽  
Fred Uchenna Nnamdi

Phenenthrene alkaloid identified as 1-ethanamino 7 hex-1-yne-5I-one phenanthrene was isolated from the ethanolic extract of the leaves ofBryophyllum pinnatum(syn. B. calcinum kalanchoe pinnata) a versatile Nigeria medicinal plant. The structure was elucidated using NMR, IR, UV and MS spectral data. Antimicrobial studies showed that the isolated compound successfully inhibitedPsuedomonas aeruginosa, Klebsiella pneumonia, Staphylococcus aureus, Escherichia coli, Candida albicansandAspergillus niger. This result authenticates the use ofbryophyllum pinantumin phytomedicine for disease prevention and treatment of infections.


Pathogens ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 110
Author(s):  
Anna K. Riebisch ◽  
Sabrina Mühlen ◽  
Yan Yan Beer ◽  
Ingo Schmitz

Autophagy is a highly conserved and fundamental cellular process to maintain cellular homeostasis through recycling of defective organelles or proteins. In a response to intracellular pathogens, autophagy further acts as an innate immune response mechanism to eliminate pathogens. This review will discuss recent findings on autophagy as a reaction to intracellular pathogens, such as Salmonella typhimurium, Listeria monocytogenes, Mycobacterium tuberculosis, Staphylococcus aureus, and pathogenic Escherichia coli. Interestingly, while some of these bacteria have developed methods to use autophagy for their own benefit within the cell, others have developed fascinating mechanisms to evade recognition, to subvert the autophagic pathway, or to escape from autophagy.


2018 ◽  
Vol 19 (0) ◽  
Author(s):  
Priscila Alves Dias ◽  
Daiani Teixeira Silva ◽  
Cláudio Dias Timm

Resumo Kefir é o produto da fermentação do leite pelos grãos de kefir. Esses grãos contêm uma mistura simbiótica de bactérias e leveduras imersas em uma matriz composta de polissacarídeos e proteínas. Muitos benefícios à saúde humana têm sido atribuídos ao kefir, incluindo atividade antimicrobiana contra bactérias Gram positivas e Gram negativas. A atividade antimicrobiana de 60 microrganismos isolados de grãos de kefir, frente à Escherichia coli O157:H7, Salmonella enterica subsp. enterica sorotipos Typhimurium e Enteritidis, Staphylococcus aureus e Listeria monocytogenes, foi estudada através do teste do antagonismo. A ação antimicrobiana dos sobrenadantes das bactérias ácido-lácticas que apresentaram atividade no teste do antagonismo foi testada. O experimento foi repetido usando sobrenadantes com pH neutralizado. Salmonella Typhimurium e Enteritidis sobreviveram por 24 horas no kefir em fermentação. E. coli O157:H7, S. aureus e L. monocytogenes foram recuperados até 72 horas após o início da fermentação. Todos os isolados apresentaram atividade antimicrobiana contra pelo menos um dos patógenos usados no teste do antagonismo. Sobrenadantes de 25 isolados apresentaram atividade inibitória e três mantiveram essa atividade com pH neutralizado. As bactérias patogênicas estudadas sobreviveram por tempo superior àquele normalmente utilizado para a fermentação do kefir artesanal, o que caracteriza perigo em potencial para o consumidor quando a matéria-prima não apresentar segurança sanitária. Lactobacillus isolados de grãos de kefir apresentam atividade antimicrobiana contra cepas de E. coli O157:H7, Salmonella sorotipos Typhimurium e Enteritidis, S. aureus e L. monocytogenes além daquela exercida pela diminuição do pH.


Author(s):  
Bing Han ◽  
Xiaoyu Han ◽  
Mengmeng Ren ◽  
Yilin You ◽  
Jicheng Zhan ◽  
...  

Diseases caused by harmful microorganisms pose a serious threat to human health. Safe and environment-friendly disinfectants are, therefore, essential in preventing and controlling such pathogens. This study aimed to investigate the antimicrobial activity and mechanism of a novel hydrogen peroxide and silver (H 2 O 2 -Ag + ) complex (HSC) in combatting Staphylococcus aureus ATCC 29213, Escherichia coli O157:H7 NCTC 12900 and Salmonella typhimurium SL 1344. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values against S. aureus were found to be 0.014 % H 2 O 2 -3.125 mg/L Ag + , while 0.028 % H 2 O 2 -6.25 mg/L Ag + for both E. coli and S. typhimurium . Results of the growth curve assay and time-kill trial suggest that the HSC could inhibit the growth of the tested bacteria, as 99.9 % of viable cells were killed following treatment at the 1 MIC for 3 h. Compared with Oxytech D10 disinfectant (0.25 % H 2 O 2 -5 mg/L Ag + ), the HSC exhibited better antibacterial efficacy at a lower concentration (0.045 % H 2 O 2 -10 mg/L Ag + ). The mechanism of antibacterial action of HSC was found including the disruption of the bacterial cell membrane, followed by entry into the bacteria cell to reduce intracellular adenosine triphosphate (ATP) concentration, and inhibit the activity of antioxidases, superoxide dismutase (SOD) and catalase (CAT). The enhanced bactericidal effect of hydrogen peroxide combined with silver indicates a potential for its application in environmental disinfection, particularly in the food industry.


1991 ◽  
Vol 54 (7) ◽  
pp. 496-501 ◽  
Author(s):  
ARTHUR HINTON ◽  
GEORGE E. SPATES ◽  
DONALD E. CORRIER ◽  
MICHAEL E. HUME ◽  
JOHN R. DELOACH ◽  
...  

A Veillonella species and Enterococcus durans were isolated from the cecal contents of adult broilers. Mixed cultures of Veillonella and E. durans inhibited the growth of Salmonella typhimurium and Escherichia coli 0157:H7 on media containing 2.5% lactose (w/v). The growth of S. typhimurium or E. coli 0157:H7 was not inhibited by mixed cultures containing Veillonella and E. durans on media containing only 0.25% lactose or by pure cultures of Veillonella or E. durans on media containing either 0.25% or 2.5% lactose. The mixed cultures of Veillonella and E. durans produced significantly (P<0.05) more acetic, propionic, and lactic acids in media containing 2.5% lactose than in media containing 0.25% lactose. The inhibition of the enteropathogens was related to the production of lactic acid from lactose by the E. durans and the production of acetic and propionic acids from lactic acid by the Veillonella.


2020 ◽  
Vol 39 (03) ◽  
Author(s):  
VĂN HỒNG THIỆN ◽  
LÊ BÍCH TRÂM ◽  
NGUYỄN THANH LAN ◽  
HỒ NGUYỄN HOÀNG YẾN ◽  
LƯU HỒNG TRƯỜNG ◽  
...  

Nghiên cứu này đã xác định được mẫu nghiên cứu thu tại Vườn quốc gia Phú Quốc là loài Homalomena pierreana. Thông qua kỹ thuật sắc ký ghép khối phổ, 10 hợp chất thuộc nhóm sesquiterpene có trong cao chiết ethanol của thân rễ loài H. pierreana đã được xác định. Ngoài ra, cao chiết ethanol từ mẫu nghiên cứu cũng cho thấy khả năng kháng lại 6 chủng vi khuẩn kiểm định là Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Salmonella enteritidis và Salmonella typhimurium.


1981 ◽  
Vol 44 (4) ◽  
pp. 271-274
Author(s):  
ADELLE W. STEWART

The fate of naturally occurring and added bacterial pathogens was determined in “soul foods” purchased at local supermarkets and farm families while the foods were stored under conditions simulating those used for retail distribution, home storage, and preparation before use. Viable count determinations for 10 samples at the end of a 5-day period at 10 C showed considerable decreases in comparison to the inoculum size, indicating that growth was not promoted. Escherichia coli survived in all the food samples but the populations decreased by 1 to 9 log cycles/g of food. Salmonella typhimurium survived in 59% of the food samples. Except for farm family collard greens and sausage (encased), Staphylococcus aureus remained viable in all of the foods tested an d was the only survivor in cracklings (cooked) obtained from both sources. Clostridium perfringens was detected in farm family sweet peas and 23% of the pig offal samples.


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