The use of rhizobium and mycorrhizae in soil containing rhizobiophage to improve growth and nodulation of cowpea

The interaction between leguminous plants and rhizosphere microorganisms is essential because it can either enhance or inhibit the beneficial effects of individual species. Phages are one of the biotic factors with a negative impact on the beneficial bacteria in soil rhizosphere. In the current study, phage showed lytic activity against Bradyrhizobium sp. Vigna (tal16) with an icosahedral head at a 43.44 nm diameter and a long non-contractile tail, measuring 99.85 nm. This phage belongs to the Siphoviridae family, found in the Met El-Ez area of Dakalia Governorate in Egypt. The results revealed that the presence of phage in soil affected nodulation and growth parameters. Mycorrhizal inoculation aggravated the negative effects of this phage. Cowpea grown in soil containing phage VB_BrV_SD4 showed a reduction in the nodule number, nitrogenase activity, and total N of 40-50 %; however, mycorrhizal inoculation augmented this negative effect with a reduction percentage to 20-28 %. Mycorrhizal inoculation also improved total chlorophyll, carotenoids, legume amount, and the seed protein content.

Characterization of a Coliphage AS1 isolated from sewage effluent in Pakistan / Caracterização de um colifago AS1 isolado de efluente de esgoto no Paquistão

The emergence of multi-drug resistant (MDR) bacterial strains, which are posing a global health threat has developed the interest of scientists to use bacteriophages instead of conventional antibiotics therapy. In light of an increased interest in the use of phage as a bacterial control agent, the study aimed to isolate and characterize lytic phages from sewage effluent. During the current study, bacteriophage AS1 was isolated from sewage effluent against E.coli S2. The lytic activity of phageAS1 was limited to E.coli S2 strain showing monovalent behavior. The calculated phage titer was 3.5×109 pfu/ml. PhageAS1 was stable at a wide range of pH and temperature. The maximum stability was recorded at 37ºC and pH 7.0, while showing its normal lytic activity at temperature 60ºC and from pH 5.0 to 11.0 respectively. At temperature 70ºC, phage activity was somewhat reduced whereas, further increase in temperature and decrease or increase in pH completely inactivated the phage. From the current study, it was concluded that waste water is a best source for finding bacteriophages against multi-drug resistant bacterial strains and can be used as bacterial control agent.

O surgimento de cepas bacterianas multirresistentes (MDR), que representam uma ameaça global à saúde, desenvolveu o interesse dos cientistas em usar bacteriófagos em vez da terapia convencional com antibióticos. Diante do crescente interesse no uso de fago como agente de controle bacteriano, o estudo visou isolar e caracterizar fagos líticos de efluente de esgoto. Durante o estudo atual, o bacteriófago AS1 foi isolado de efluente de esgoto contra E. coli S2. A atividade lítica de phageAS1 foi limitada à cepa E. coli S2, apresentando comportamento monovalente. O título de fago calculado foi de 3,5 x 109 ufp/ml. PhageAS1 foi estável em uma ampla faixa de pH e temperatura. A estabilidade máxima foi registrada a 37ºC e pH 7,0, enquanto mostrou atividade lítica normal em temperatura de 60ºC e pH 5,0 a 11,0, respectivamente. Na temperatura de 70ºC, a atividade do fago foi um pouco reduzida, enquanto o aumento adicional da temperatura e a diminuição ou aumento do pH inativaram completamente o fago. Com base no estudo atual, concluiu-se que a água residual é a melhor fonte para encontrar bacteriófagos contra cepas bacterianas multirresistentes e pode ser usada como agente de controle bacteriano.

Characterization of a Coliphage AS1 isolated from sewage effluent in Pakistan

Abstract The emergence of multi-drug resistant (MDR) bacterial strains, which are posing a global health threat has developed the interest of scientists to use bacteriophages instead of conventional antibiotics therapy. In light of an increased interest in the use of phage as a bacterial control agent, the study aimed to isolate and characterize lytic phages from sewage effluent. During the current study, bacteriophage AS1 was isolated from sewage effluent against E.coli S2. The lytic activity of phageAS1 was limited to E.coli S2 strain showing monovalent behavior. The calculated phage titer was 3.5×109 pfu/ml. PhageAS1 was stable at a wide range of pH and temperature. The maximum stability was recorded at 37ºC and pH 7.0, while showing its normal lytic activity at temperature 60ºC and from pH 5.0 to11.0 respectively. At temperature 70ºC, phage activity was somewhat reduced whereas, further increase in temperature and decrease or increase in pH completely inactivated the phage. From the current study, it was concluded that waste water is a best source for finding bacteriophages against multi-drug resistant bacterial strains and can be used as bacterial control agent.

Resumo O surgimento de cepas bacterianas multirresistentes (MDR), que representam uma ameaça global à saúde, desenvolveu o interesse dos cientistas em usar bacteriófagos em vez da terapia convencional com antibióticos. Diante do crescente interesse no uso de fago como agente de controle bacteriano, o estudo visou isolar e caracterizar fagos líticos de efluente de esgoto. Durante o estudo atual, o bacteriófago AS1 foi isolado de efluente de esgoto contra E. coli S2. A atividade lítica de phageAS1 foi limitada à cepa E. coli S2, apresentando comportamento monovalente. O título de fago calculado foi de 3,5 x 109 ufp/ml. PhageAS1 foi estável em uma ampla faixa de pH e temperatura. A estabilidade máxima foi registrada a 37ºC e pH 7,0, enquanto mostrou atividade lítica normal em temperatura de 60ºC e pH 5,0 a 11,0, respectivamente. Na temperatura de 70ºC, a atividade do fago foi um pouco reduzida, enquanto o aumento adicional da temperatura e a diminuição ou aumento do pH inativaram completamente o fago. Com base no estudo atual, concluiu-se que a água residual é a melhor fonte para encontrar bacteriófagos contra cepas bacterianas multirresistentes e pode ser usada como agente de controle bacteriano.

Characterization of a Coliphage AS1 isolated from sewage effluent in Pakistan / Caracterização de um colifago AS1 isolado de efluente de esgoto no Paquistão

The emergence of multi-drug resistant (MDR) bacterial strains, which are posing a global health threat has developed the interest of scientists to use bacteriophages instead of conventional antibiotics therapy. In light of an increased interest in the use of phage as a bacterial control agent, the study aimed to isolate and characterize lytic phages from sewage effluent. During the current study, bacteriophage AS1 was isolated from sewage effluent against E.coli S2. The lytic activity of phageAS1 was limited to E.coli S2 strain showing monovalent behavior. The calculated phage titer was 3.5×109 pfu/ml. PhageAS1 was stable at a wide range of pH and temperature. The maximum stability was recorded at 37ºC and pH 7.0, while showing its normal lytic activity at temperature 60ºC and from pH 5.0 to11.0 respectively. At temperature 70ºC, phage activity was somewhat reduced whereas, further increase in temperature and decrease or increase in pH completely inactivated the phage. From the current study, it was concluded that waste water is a best source for finding bacteriophages against multi-drug resistant bacterial strains and can be used as bacterial control agent.

O surgimento de cepas bacterianas multirresistentes (MDR), que representam uma ameaça global à saúde, desenvolveu o interesse dos cientistas em usar bacteriófagos em vez da terapia convencional com antibióticos. Diante do crescente interesse no uso de fago como agente de controle bacteriano, o estudo visou isolar e caracterizar fagos líticos de efluente de esgoto. Durante o estudo atual, o bacteriófago AS1 foi isolado de efluente de esgoto contra E. coli S2. A atividade lítica de phageAS1 foi limitada à cepa E. coli S2, apresentando comportamento monovalente. O título de fago calculado foi de 3,5 x 109 ufp/ml. PhageAS1 foi estável em uma ampla faixa de pH e temperatura. A estabilidade máxima foi registrada a 37ºC e pH 7,0, enquanto mostrou atividade lítica normal em temperatura de 60ºC e pH 5,0 a 11,0, respectivamente. Na temperatura de 70ºC, a atividade do fago foi um pouco reduzida, enquanto o aumento adicional da temperatura e a diminuição ou aumento do pH inativaram completamente o fago. Com base no estudo atual, concluiu-se que a água residual é a melhor fonte para encontrar bacteriófagos contra cepas bacterianas multirresistentes e pode ser usada como agente de controle bacteriano.

Characterization of a Coliphage AS1 isolated from sewage effluent in Pakistan / Caracterização de um colifago AS1 isolado de efluente de esgoto no Paquistão

The emergence of multi-drug resistant (MDR) bacterial strains, which are posing a global health threat has developed the interest of scientists to use bacteriophages instead of conventional antibiotics therapy. In light of an increased interest in the use of phage as a bacterial control agent, the study aimed to isolate and characterize lytic phages from sewage effluent. During the current study, bacteriophage AS1 was isolated from sewage effluent against E.coli S2. The lytic activity of phageAS1 was limited to E.coli S2 strain showing monovalent behavior. The calculated phage titer was 3.5×109 pfu/ml. PhageAS1 was stable at a wide range of pH and temperature. The maximum stability was recorded at 37ºC and pH 7.0, while showing its normal lytic activity at temperature 60ºC and from pH 5.0 to 11.0 respectively. At temperature 70ºC, phage activity was somewhat reduced whereas, further increase in temperature and decrease or increase in pH completely inactivated the phage. From the current study, it was concluded that waste water is a best source for finding bacteriophages against multi-drug resistant bacterial strains and can be used as bacterial control agent.(AU)

O surgimento de cepas bacterianas multirresistentes (MDR), que representam uma ameaça global à saúde, desenvolveu o interesse dos cientistas em usar bacteriófagos em vez da terapia convencional com antibióticos. Diante do crescente interesse no uso de fago como agente de controle bacteriano, o estudo visou isolar e caracterizar fagos líticos de efluente de esgoto. Durante o estudo atual, o bacteriófago AS1 foi isolado de efluente de esgoto contra E. coli S2. A atividade lítica de phageAS1 foi limitada à cepa E. coli S2, apresentando comportamento monovalente. O título de fago calculado foi de 3,5 x 109 ufp/ml. PhageAS1 foi estável em uma ampla faixa de pH e temperatura. A estabilidade máxima foi registrada a 37ºC e pH 7,0, enquanto mostrou atividade lítica normal em temperatura de 60ºC e pH 5,0 a 11,0, respectivamente. Na temperatura de 70ºC, a atividade do fago foi um pouco reduzida, enquanto o aumento adicional da temperatura e a diminuição ou aumento do pH inativaram completamente o fago. Com base no estudo atual, concluiu-se que a água residual é a melhor fonte para encontrar bacteriófagos contra cepas bacterianas multirresistentes e pode ser usada como agente de controle bacteriano.(AU)

In-Vitro Adhesion and Invasion Properties of Salmonella Typhimurium Competing with Bacteriophage in Epithelial Cells and Chicken Macrophages

This study was designed to assess the role of bacteriophage P22 in the adhesion, invasion, intracellular survival of, and cellular immune response to Salmonella Typhimurium in intestinal epithelial INT-407 and chicken macrophage-like HD11 cells. The ability of S. Typhimurium to adhere, invade, and survive to INT-407 and HD11cells was evaluated under Salmonella infection alone (control), phage treatment followed by Salmonella infection (PS), Salmonella infection followed by phage treatment (SP), and a combination treatment with Salmonella and phage (S+P). The number of S. Typhimurium associated on INT-407 cells was reduced from 4.2 to 2.7 log cfu/cm2 by phage treatment (SP). The number of intracellular S. Typhimurium within INT-407 cells was significantly reduced to below the detection limit (0.7 log cfu/cm2) compared with the control (3.4 log cfu/cm2). S. Typhimurium remained inside HD11 cells at 49% and 17% levels in the absence and presence of phages, respectively, at 24 h post-infection (hpi). The expression levels of IFN-g, IL-10, IL-1b, IL-6, IL-8, iNOS, and IL-12 increased in HD11 cells regardless the absence and presence of phages, while those of IL-16, TLR2-1, TLR3, and TLR7 were decreased at 0 and 24 hpi. This study sheds new light on our understanding of the role of phages in Salmonella adhesion, invasion, survival, and cellular immune responses.

In-Vitro Adhesion and Invasion Properties of Salmonella Typhimurium Competing with Bacteriophage in Epithelial Cells and Chicken Macrophages

This study was designed to assess the role of bacteriophage P22 in the adhesion, invasion, intracellular survival of, and cellular immune response to Salmonella Typhimurium in intestinal epithelial INT-407 and chicken macrophage-like HD11 cells. The ability of S. Typhimurium to adhere, invade, and survive to INT-407 and HD11cells was evaluated under Salmonella infection alone (control), phage treatment followed by Salmonella infection (PS), Salmonella infection followed by phage treatment (SP), and a combination treatment with Salmonella and phage (S+P). The number of S. Typhimurium associated on INT-407 cells was reduced from 4.2 to 2.7 log cfu/cm2 by phage treatment (SP). The number of intracellular S. Typhimurium within INT-407 cells was significantly reduced to below the detection limit (0.7 log cfu/cm2) compared with the control (3.4 log cfu/cm2). S. Typhimurium remained inside HD11 cells at 49% and 17% levels in the absence and presence of phages, respectively, at 24 h post-infection (hpi). The expression levels of IFN-g, IL-10, IL-1b, IL-6, IL-8, iNOS, and IL-12 increased in HD11 cells regardless the absence and presence of phages, while those of IL-16, TLR2-1, TLR3, and TLR7 were decreased at 0 and 24 hpi. This study sheds new light on our understanding of the role of phages in Salmonella adhesion, invasion, survival, and cellular immune responses.(AU)

Isolation of Dickeya dadantii strains from potato disease and biocontrol by their bacteriophages

One of the most economically important bacterial pathogens of plants and plant products is Dickeya dadantii. This bacterium causes soft rot disease in tubers and other parts of the potato and other plants of the Solanaceae family. The application of restricted host range bacteriophages as biocontrol agents has recently gained widespread interest. This study purposed to isolate the infectious agent of the potato and evaluate its biocontrol by bacteriophages. Two phytopathogenic strains were isolated from infected potatoes, identified based on biochemical and 16S rRNA gene sequencing, and submitted to GenBank as D. dadantii strain pis3 (accession no. HQ423668) and D. dadantii strain sip4 (accession no. HQ423669). Their bacteriophages were isolated from Caspian Sea water by enriching the water filtrate with D. dadantii strains as hosts using spot or overlay methods. On the basis of morphotypes, the isolated bacteriophages were identified as members of the Myoviridae and Siphoviridae families and could inhibit the growth of antibiotic resistant D. dadantii strains in culture medium. Moreover, in Dickeya infected plants treated with bacteriophage, no disease progression was detected. No significant difference was seen between phage-treated and control plants. Thus, isolated bacteriophages can be suggested for the biocontrol of plant disease caused by Dickeya strains..(AU)

Control of Listeria monocytogenes growth in soft cheeses by bacteriophage P100

The purpose of this study was to determine the effect of bacteriophage P100 on strains of Listeria monocytogenes in artificially inoculated soft cheeses. A mix of L. monocytogenes 1/2a and Scott A was inoculated in Minas Frescal and Coalho cheeses (approximately 10(5) cfu/g) with the bacteriophage added thereafter (8.3 x 10(7) PFU/g). Samples were analyzed immediately, and then stored at 10 ºC for seven days. At time zero, 30 min post-infection, the bacteriophage P100 reduced L. monocytogenes counts by 2.3 log units in Minas Frescal cheese and by 2.1 log units in Coalho cheese, compared to controls without bacteriophage. However, in samples stored under refrigeration for seven days, the bacteriophage P100 was only weakly antilisterial, with the lowest decimal reduction (DR) for the cheeses: 1.0 log unit for Minas Frescal and 0.8 log units for Coalho cheese. The treatment produced a statistically significant decrease in the counts of viable cells (p < 0.05) and in all assays performed, we observed an increase of approximately one log cycle in the number of viable cells of L. monocytogenes in the samples under refrigeration for seven days. Moreover, a smaller effect of phages was observed. These results, along with other published data, indicate that the effectiveness of the phage treatment depends on the initial concentration of L. monocytogenes, and that a high concentration of phages per unit area is required to ensure sustained inactivation of target pathogens on food surfaces.(AU)

Bacteriophage amplification assay for detection of Listeria spp. using virucidal laser treatment

A protocol for the bacteriophage amplification technique was developed for quantitative detection of viable Listeria monocytogenes cells using the A511 listeriophage with plaque formation as the end-point assay. Laser and toluidine blue O (TBO) were employed as selective virucidal treatment for destruction of exogenous bacteriophage. Laser and TBO can bring a total reduction in titer phage (ca. 10(8) pfu/mL) without affecting the viability of L. monocytogenes cells. Artificially inoculated skimmed milk revealed mean populations of the bacteria as low as between 13 cfu/mL (1.11 log cfu/mL), after a 10-h assay duration. Virucidal laser treatment demonstrated better protection of Listeria cells than the other agents previously tested. The protocol was faster and easier to perform than standard procedures. This protocol constitutes an alternative for rapid, sensitive and quantitative detection of L. monocytogenes.

Fagoterapia: uma opção de controle biológico para a salmonelose aviária / Phage therapy: an option of biological control for avian salmonelosis

Com a grande expansão da indústria avícola, a salmonelose tornou-se fator limitante na criação de aves, pois as perdas econômicas estão presentes em todas as fases. O aumento mundial da resistência bacteriana tornou necessária a buscapor alternativas para controle desta doença fazendo ressurgir a fagoterapia como opção. O presente artigo revisa o fenômeno da bacteriofagia voltado para sua aplicação no controle da salmonelose aviária, usando como modelo os conhecimentos sobre o bacteriófago P22.

With the enormous expansion in the poultry industry, salmonellosis became a limiting factor on avian production, because ofthe important economic losses during the production stages. The world wide increase in bacterial resistance stimulated the searchfor alternative strategies to control the disease and so phagoteraphy has been reconsidered as a therapeutic option. This article reviews the phenomenon of bacteriophagia focusing on its usefor the control of avian salmonellosis, using the P22 bacteriophageas a model.

Fagoterapia: uma opção de controle biológico para a salmonelose aviária / Phage therapy: an option of biological control for avian salmonelosis

Com a grande expansão da indústria avícola, a salmonelose tornou-se fator limitante na criação de aves, pois as perdas econômicas estão presentes em todas as fases. O aumento mundial da resistência bacteriana tornou necessária a buscapor alternativas para controle desta doença fazendo ressurgir a fagoterapia como opção. O presente artigo revisa o fenômeno da bacteriofagia voltado para sua aplicação no controle da salmonelose aviária, usando como modelo os conhecimentos sobre o bacteriófago P22.(AU)

With the enormous expansion in the poultry industry, salmonellosis became a limiting factor on avian production, because ofthe important economic losses during the production stages. The world wide increase in bacterial resistance stimulated the searchfor alternative strategies to control the disease and so phagoteraphy has been reconsidered as a therapeutic option. This article reviews the phenomenon of bacteriophagia focusing on its usefor the control of avian salmonellosis, using the P22 bacteriophageas a model.(AU)

GENÔMICA E CARACTERIZAÇÃO FENOTÍPICA DE BACTERIÓFAGOS LÍTICOS PARA BIOCONTROLE DE SALMONELLA ENTERICA

Salmonella spp. é um dos principais patógenos envolvidos em surtos de doenças transmitidas por alimentos (DTA). É um dos agentes patogênicos de maior prevalência em produtos avícolas em diversos países, com distribuição mundial e destacada relevância em saúde pública. Não obstante, a resistência bacteriana aos antimicrobianos representa risco à saúde humana e animal, devido à dificuldade terapêutica e pela possibilidade de transmissão horizontal dos genes de resistência entre diferentes bactérias. Desta maneira, ressalta-se a necessidade de novas ferramentas para tratamento frente a estes patógenos. Dentre elas, destacam-se o controle biológico com uso de bacteriófagos, que são vírus bacterianos, intracelulares obrigatórios, hospedeiro-específico, que infectam somente procariotos. A utilização de bacteriófagos é uma alternativa à antibioticoterapia que, além da prevenção, também pode ser considerada complementar ao uso de terapias convencionais. Assim, no Capítulo 1 testamos a suscetibilidade bacteriana ao bacteriófago P22 a diferentes sorovares de Salmonella enterica. Verificamos que o fago P22 teve ação de lítica ao infectar cepas distintas de Salmonella. No Capítulo 2, selecionamos 12 sorovares de Salmonella enterica (S.Anatum, S. Agona, S. Brandenburg, S. Bredeney, S. Infantis, S. Lexington, S. Panama, S. Rissen, S. Schwarzengrund, S. Tennessee, S. Enteritidis ATCC 13076 e S. Typhimurium ATCC 14028) como bactérias hospedeiras para o isolamento e caracterização fenotípica de bacteriófagos líticos com ação frente a essas bactérias. Foi isolado, caracterizado e sequenciado um novo bacteriófago, ainda não descrito, denominado Salmonella Phage UPF_BP1, que tem o genoma circular, DNA fita dupla, 39.902 pb, pertence à ordem Caudovirales e à família Podoviridae. Nenhuma das proteínas hipotéticas do Salmonella Phage UPF_BP1 mostrou semelhança significativa com fatores conhecidos ou envolvidos na patogenicidade bacteriana. O novo fago confirmou ação lítica frente às cepas testadas, demonstrando ser possível utilizá-lo em futuras aplicações no biocontrole e fagoterapia de Salmonella enterica. Entretanto vale ressaltar que também isolamos outro bacteriófago, denominado 5:2, que está em fase de seqüenciamento genético.

Salmonella spp. it is one of the main pathogens involved in disease outbreaks foodborne (DTA). It is one of the pathogens most prevalent in poultry products in several countries, with world and highlighted important public health distribution. However, bacterial resistance to antimicrobials is a risk to human and animal health due to therapeutic difficulties and the possibility of horizontal transmission of resistance genes between different bacteria. Thus, it emphasizes the need for new tools for treatment against these pathogens. Among them, there is the biological control with the use of bacteriophages, which are bacterial viruses, intracellular binding, host-specific, infecting only prokaryotes. The use of bacteriophage is an alternative to antibiotic therapy, in addition to prevention, it can also be considered supplementary to the use of conventional therapies. Thus, in Chapter 1 we tested the bacterial susceptibility to bacteriophage P22 to different serotypes of Salmonella enterica. We found that the P22 phage lytic action had to infect different strains of Salmonella. In Chapter 2, we selected 12 serotypes of Salmonella enterica (S. Anatum, S. Agona, S. Brandenburg, S. Bredeney, S. Infantis, S. Lexington, S. Panama, S. Rissen, S. Schwarzengrund, S. Tennessee S. Enteritidis ATCC 13076 and S. Typhimurium ATCC 14028) as host bacteria for the isolation and phenotypic characterization of bacteriophage lytic action opposite to these bacteria. It was isolated, characterized and sequenced a new bacteriophage, not yet described, called Salmonella phage UPF_BP1, which has the circular genome, double-stranded DNA, 39,902 bp., Caudovirales belongs to the order and Podoviridae family. None of the hypothetical Salmonella phage UPF_BP1 proteins showed significant similarity with known or factors involved in bacterial pathogenicity. The new phage lytic action confirmed front of the strains tested, proving to be able to use it in future applications in biocontrol and phage therapy of Salmonella enterica. However it is noteworthy that also isolate another bacteriophage, named 5: 2, which is in genetic sequencing phase.

UTILIZAÇÃO DE BACTERIÓFAGOS AMBIENTAIS NO CONTROLE DE BIOFILMES DE Salmonella spp. EM SUPERFÍCIES UTILIZADAS NA INDÚSTRIA DE PROCESSAMENTO E COMERCIALIZAÇÃO DE FRANGO DE CORTE E DERIVADOS

O biofilme representa uma importante fonte de contaminação de alimentos, podendo estar presente em vários pontos da cadeia de processamento da carne de frango. O controle do biofilme na indústria alimentícia necessita de métodos alternativos, a fim de superar a resistência a desinfetantes comuns e garantir um alimento livre de resíduos químicos. Os objetivos deste estudo foram avaliar a influência das superfícies de inox, vidro e PVC sobre a formação de biofilmes de Salmonella spp. em diferentes momentos, e avaliar a ação lítica de um pool de bacteriófagos sobre biofilmes destas bactérias. A maioria das amostras foi classificada como fracas produtoras de biofilme, e os sorovares Heidelberg e Enteritidis apresentaram um número significativamente maior de amostras formadoras. As superfícies de inox e vidro favoreceram significativamente a formação de biofilme em três e cinco períodos, respectivamente. O pool de bacteriófagos reduziu a formação de biofilme nas superfícies de inox, vidro e PVC, e seu período de ação concentrou-se principalmente em 3h, porém estes resultados não foram estatisticamente significantes. Nossos achados sugerem que o sorovar e a superfície envolvidos podem interferir significativamente na produção de biofilme, porém através dos métodos utilizados neste estudo, não podemos confirmar a ação de bacteriófagos sobre biofilmes de Salmonella spp. nas superfícies de vidro, inox e PVC.

Biofilm is a major source of food contamination and may be present in various parts of the chicken meat processing chain. The control of biofilm in the food industry needs alternative methods in order to overcome resistance to disinfectants and ensure food free of chemical residues. The objective of this study was to evaluate the influence of the surfaces of stainless steel, glass and PVC in the biofilm formation by Salmonella spp. at different times and evaluate the action of a pool of bacteriophages against this bacterial biofilms. Most samples were classified as weak biofilm producers. Heidelberg and Enteritidis serotypes showed a significantly higher number of samples capable to produce biofilm. The surfaces of stainless steel and glass significantly favored the biofilm formation in three and five periods, respectively. The bacteriophage pool reduced biofilm formation on the surfaces of stainless steel, glass and PVC and its action period focused mainly at 3h. Our findings suggests that there is a difference in the production of biofilms by different serotypes of Salmonella spp., as well as significantly interference of the surfaces in the production of biofilms by this bacteria, however more studies should be conducted in order to characterize the bacteriophage action in the control of biofilms.

Phage amplification assay as rapid method for Salmonella detection

The application of rapid methods is crucial for the HACCP program implantation in food industry. In this context, Phage Amplification Assay is a good candidate because is based on the interactions of phage and their host bacteria. This method using phage P22 was applied with to detect Salmonella cells in chicken breast. Samples of 25 g of chicken breast were diluted and the appropriate dilutions were used in phage amplification assay for Salmonella detection. After 3-4 h of incubation, it was observed a phage titre of approximately 10(4) pfu mL-1, indicating that there were Salmonella cells which were naturally present in the meat. The presence of Salmonella cells were verified by using direct plating on XLD agar and by conventional enrichment procedure. The colonies suspected to be Salmonella were serologically tested and were identified as belonging to the serogroups B (S. typhimurium group) and D (S. enteritidis group). It can be concluded that this method provides a rapid and alternative application for Salmonella detection in food samples reducing both time and laboratory work to 3-4 hours.

A aplicação de métodos rápidos é crucial para a implantação de programas de HACCP em indústrias de alimentos. Neste contexto, o método de amplificação de bacteriófagos é um instrumento de diagnóstico importante porque está baseado na interação dos bacteriófagos com suas células hospedeiras. Este método, usando o bacteriófago P22, foi aplicado para detectar Salmonella em peito de frango. Amostras de 25 g de peito de frango foram diluídas e as diluições apropriadas foram usadas no método de amplificação de bacteriófagos na detecção de Salmonella. Após 3-4 horas de incubação, foi observado uma titulação de partículas virais de, aproximadamente, 10(4) ufp mL-1 (unidades formadoras de placas virais), indicando a presença de células de Salmonella na carne de frango. A comprovação da presença de Salmonella neste produto foi verificada usando-se plaqueamento direto em ágar XLD e procedimento de enriquecimento convencional. As colônias suspeitas de Salmonella foram sorologicamente testadas e identificadas como pertencendo aos sorogrupos B (grupo de S. typhimurium) e D (grupo de S. enteritidis). Portanto, concluiu-se que este método pode ser aplicado, na detecção de Salmonella em alimentos, porque fornece rápido e conclusivo resultado, reduzindo o tempo de análise e o trabalho laboratorial para 3-4 horas.

Phage amplification assay as rapid method for Salmonella detection

The application of rapid methods is crucial for the HACCP program implantation in food industry. In this context, Phage Amplification Assay is a good candidate because is based on the interactions of phage and their host bacteria. This method using phage P22 was applied with to detect Salmonella cells in chicken breast. Samples of 25 g of chicken breast were diluted and the appropriate dilutions were used in phage amplification assay for Salmonella detection. After 3-4 h of incubation, it was observed a phage titre of approximately 10(4) pfu mL-1, indicating that there were Salmonella cells which were naturally present in the meat. The presence of Salmonella cells were verified by using direct plating on XLD agar and by conventional enrichment procedure. The colonies suspected to be Salmonella were serologically tested and were identified as belonging to the serogroups B (S. typhimurium group) and D (S. enteritidis group). It can be concluded that this method provides a rapid and alternative application for Salmonella detection in food samples reducing both time and laboratory work to 3-4 hours.

A aplicação de métodos rápidos é crucial para a implantação de programas de HACCP em indústrias de alimentos. Neste contexto, o método de amplificação de bacteriófagos é um instrumento de diagnóstico importante porque está baseado na interação dos bacteriófagos com suas células hospedeiras. Este método, usando o bacteriófago P22, foi aplicado para detectar Salmonella em peito de frango. Amostras de 25 g de peito de frango foram diluídas e as diluições apropriadas foram usadas no método de amplificação de bacteriófagos na detecção de Salmonella. Após 3-4 horas de incubação, foi observado uma titulação de partículas virais de, aproximadamente, 10(4) ufp mL-1 (unidades formadoras de placas virais), indicando a presença de células de Salmonella na carne de frango. A comprovação da presença de Salmonella neste produto foi verificada usando-se plaqueamento direto em ágar XLD e procedimento de enriquecimento convencional. As colônias suspeitas de Salmonella foram sorologicamente testadas e identificadas como pertencendo aos sorogrupos B (grupo de S. typhimurium) e D (grupo de S. enteritidis). Portanto, concluiu-se que este método pode ser aplicado, na detecção de Salmonella em alimentos, porque fornece rápido e conclusivo resultado, reduzindo o tempo de análise e o trabalho laboratorial para 3-4 horas.

Phage amplification assay as rapid method for Salmonella detection

The application of rapid methods is crucial for the HACCP program implantation in food industry. In this context, Phage Amplification Assay is a good candidate because is based on the interactions of phage and their host bacteria. This method using phage P22 was applied with to detect Salmonella cells in chicken breast. Samples of 25 g of chicken breast were diluted and the appropriate dilutions were used in phage amplification assay for Salmonella detection. After 3-4 h of incubation, it was observed a phage titre of approximately 10(4) pfu mL-1, indicating that there were Salmonella cells which were naturally present in the meat. The presence of Salmonella cells were verified by using direct plating on XLD agar and by conventional enrichment procedure. The colonies suspected to be Salmonella were serologically tested and were identified as belonging to the serogroups B (S. typhimurium group) and D (S. enteritidis group). It can be concluded that this method provides a rapid and alternative application for Salmonella detection in food samples reducing both time and laboratory work to 3-4 hours.

A aplicação de métodos rápidos é crucial para a implantação de programas de HACCP em indústrias de alimentos. Neste contexto, o método de amplificação de bacteriófagos é um instrumento de diagnóstico importante porque está baseado na interação dos bacteriófagos com suas células hospedeiras. Este método, usando o bacteriófago P22, foi aplicado para detectar Salmonella em peito de frango. Amostras de 25 g de peito de frango foram diluídas e as diluições apropriadas foram usadas no método de amplificação de bacteriófagos na detecção de Salmonella. Após 3-4 horas de incubação, foi observado uma titulação de partículas virais de, aproximadamente, 10(4) ufp mL-1 (unidades formadoras de placas virais), indicando a presença de células de Salmonella na carne de frango. A comprovação da presença de Salmonella neste produto foi verificada usando-se plaqueamento direto em ágar XLD e procedimento de enriquecimento convencional. As colônias suspeitas de Salmonella foram sorologicamente testadas e identificadas como pertencendo aos sorogrupos B (grupo de S. typhimurium) e D (grupo de S. enteritidis). Portanto, concluiu-se que este método pode ser aplicado, na detecção de Salmonella em alimentos, porque fornece rápido e conclusivo resultado, reduzindo o tempo de análise e o trabalho laboratorial para 3-4 horas.

Phage typing strains of Staphylococcus aureus resistant to antibiotics, isolated from milk / Fagotipagem de cepas de Staphylococcus aureus resistentes a antibióticos, isoladas de leite

In this study, 201 strains of S. aureus were isolated from crude milk and submitted to antibiotic resistance by the disc diffusion method using impregnated paper discs with the following antibiotics: amikacin, ampicillin, cephalotin, cephoxitin, chloramphenicol, clindamycin, oxacylin, penicillin, tetracycline, tobramycin and vancomycin. With the exception of 88 (43.8%), 90 (44.8%), 24 (11.9%) e 40 (19.9%) resistant strains to penicillin, ampicillin, chloramphenicol and tetracycline, respectively, it was verified that most of the 201 strains (95% or more) showed sensitivity to the others tested antibiotics. The strains resistant to these four antibiotics were phage-typified with the basic international set of phages for S. aureus of human and bovine origin and showed predominant sensitivity to the phage of the groups III and III/No Classified from the human basic set and to the phage groups III, IV and to the association III/IV from the bovine set.

A partir de amostras de leite cru foram isoladas 201 cepas de S. aureus, as quais foram submetidas a provas de resistência a antibióticos pelo método dos discos impregnados com os seguintes antibacterianos: amicacina, ampicilina, cefalotina, cefoxitina, cloranfenicol, clindamicina, oxacilina, penicilina, tetraciclina, tobramicina e vancomicina. Com exceção de 88 (43,8%), 90 (44,8%), 24 (11,9%) e 40 (19,9%) cepas resistentes à penicilina, ampicilina, cloranfenicol e tetraciclina, respectivamente, a maioria das 201 cepas (95% ou mais) foi sensível aos antibióticos utilizados. As cepas resistentes a estes quatro antibióticos foram fagotipadas, empregando-se os Conjuntos Básicos Internacionais de bacteriófagos para cepas de origem humana e bovina, verificando-se que houve predomínio de cepas sensíveis a fagos dos grupos III e III/NC do conjunto básico humano e a fagos dos grupos III, IV e da associação III/IV do conjunto bovino.