A comparison of PCR and LAMP methods for detecting shiga toxin producing Escherichia coli / Монголын Анагаах Ухаан

Introduction@#PCR to detect and amplificate the virulence genes of STEC is specific and more sensitive, however, it takes five to six hours for whole test procedure and requires special lab instruments such as thermocycler. Loop-mediated isothermal amplification is a simple, rapid, specific and cost-effective nucleic acid amplification method by using four to six primers when compared to PCR, nucleic acid sequence-based amplification, self-sustained sequence replication and strand displacement amplification.@*Materials and Methods@#In our study, we analyzed comparison of PCR and LAMP results on standard strain used quality control strain solution which diluted 1pg/µL DNA, 10 pg/µL DNA, 100 pg/µL DNA, 1 ng/μL DNA, 10 ng/μL DNA, and 100 ng/μL DNA concentration from LB agar cultures. @*Research ethics@#Permission to submit the survey was granted by the Ethics Review Committee of the MNUMS and the survey was conducted in accordance with the rules and regulations. @*Goal@#Detection and comparison of STEC by PCR and LAMP@*Result@#Sensitivity of Stx1 and stx2 genes in PCR results are positive in 10 pg/µL DNA solution and negative in 1pg/µL DNA. In LAMP test results showed that positive for all concentration. It shows that LAMP method sensitivity is 10 times more than PCR. @*Conclusion@#It shows that LAMP method sensitivity is 10 times more than PCR. All in allLAMP test is cost effective test with sensitive for detection STEC.

A comparison of PCR and LAMP methods for detecting shiga toxin producing escherichia coli / Монголын Анагаах Ухаан

Introduction@#PCR to detect and amplificate the virulence genes of STEC is specific and more sensitive, however, it takes five to six hours for whole test procedure and requires special lab instruments such as thermocycler. Loop-mediated isothermal amplification is a simple, rapid, specific and cost-effective nucleic acid amplification method by using four to six primers when compared to PCR, nucleic acid sequence-based amplification, self-sustained sequence replication and strand displacement amplification.@*Goal@#Detection and comparison of STEC by PCR and LAMP@*Materials and Methods@#In our study, we analyzed comparison of PCR and LAMP results on standard strain used quality control strain solution which diluted 1pg/µL DNA, 10 pg/µL DNA, 100 pg/µL DNA, 1 ng/μL DNA, 10 ng/μL DNA, and 100 ng/μL DNA concentration from LB agar cultures. @*Research ethics@#Permission to submit the survey was granted by the Ethics Review Committee of the MNUMS and the survey was conducted in accordance with the rules and regulations.@*Result@#Sensitivity of Stx1 and stx2 genes in PCR results are positive in 10 pg/µL DNA solution and negative in 1pg/µL DNA. In LAMP test results showed that positive for all concentration. It shows that LAMP method sensitivity is 10 times more than PCR. @*Conclusion@#It shows that LAMP method sensitivity is 10 times more than PCR. All in allLAMP test is cost effective test with sensitive for detection STEC.

Estudo do composto STX140, um análogo do estradiol, em linhagens de melanoma humano / STX140 compound study in human melanoma

O câncer de pele pode ser classificado como não melanoma e melanoma. O melanoma apresenta baixa incidência entre os cânceres de pele, porém é a forma mais letal e é considerado um dos tipos mais resistentes ao tratamento. Devido à infiltração de células malignas nos tecidos, vasos linfáticos e vasos sanguíneos, o melanoma invade e se espalha rapidamente. Suas metástases são frequentemente localizadas em linfonodos, cérebro, fígado e outros órgãos. Melanomas metastáticos abrigam múltiplas mutações gênicas e muitos tumores apresentam resistência aos tratamentos, como por exemplo com inibidores BRAF, devido à mutações e ativação de vias paralelas. Ou seja, existe uma necessidade clara da busca de novas opções de tratamento. Em trabalho realizado por nosso grupo, Massaro et al mostraram que o derivado de estradiol 2- Metoxiestradiol induz apoptose em células de melanoma e senescência. Neste sentido, o composto STX140, (um análogo do estradiol com biodisponibilidade superior), que já se mostrou eficaz no combate ao câncer de mama em diversos estudos in vitro e in vivo, será então avaliado para sua ação no melanoma de forma inédita. Este trabalho teve como principal objetivo explorar a ação antitumoral em células de melanoma do composto STX140, especialmente a indução de senescência. Utilizando a cultura de células de melanoma foram realizados os ensaios de: viabilidade celular - IC50, formação de colônias, análise do ciclo celular e caracterização de morte celular por citometria de fluxo, ensaio In vitro scratch, coloração para ß-galactosidase, PCR quantitativo e ELISA. Os resultados mostraram que o composto STX140: diminui a viabilidade celular, inibe a proliferação, formação de colônias e migração em linhagens de melanoma (não resistentes e resistentes ao vemurafenibe, inibidor de BRAF). Além do mais, o composto atuou diminuindo a secreção da interleucina pró-tumoral IL-8 em células resistentes. O STX140 induziu senescência nas células de melanoma que foram positivas para ß-galactosidase, também havendo aumento da expressão de genes chave de vias de senescência (CDKN1A e GADD45A) nas células de melanoma resistentes tratadas com o composto. Em conclusão, o STX140 mostrou ter um potencial antitumoral contra o melanoma, diminuindo sua viabilidade celular, inibindo sua proliferação e migração, induzindo senescência, diminuindo a secreção de interleucina pró- tumoral, com efeito mais acentuado nas linhagens de melanoma resistente

Skin cancer can be classified as non-melanoma and melanoma. Melanoma has a low incidence among skin cancers, but it is the most lethal form and is considered one of the most resistant to treatment. Due to the infiltration of malignant cells into tissues, lymphatic vessels and blood vessels, melanoma invades and spreads rapidly. Its metastases are often located in lymph nodes, brain, liver and other organs. Metastatic melanomas presents multiple gene mutations and many tumors are resistant to treatments, such as with BRAF inhibitors, due to mutations and activation of parallel pathways. In other words, there is a clear need to search for new treatment options. In work carried out by our group, Massaro et al showed that the estradiol derivative 2- Methoxyestradiol induces apoptosis in melanoma cells and senescence. In this sense, the compound STX140, (an estradiol analogue with superior bioavailability), which has already been shown to be effective against breast cancer in vitro and in vivo studies will be then evaluated for its action on melanoma. The main objective of this work is to explore the antitumor action of the compound STX140 in melanoma cells, especially the induction of senescence. Using the melanoma cell culture the following assays were performed: cell viability - IC50, clonogenic, cell cycle analysis and cell death characterization by flow cytometry, wound assay, staining for ß-galactosidase, quantitative PCR and ELISA. Preliminary data from this work showed that the compound STX140: decreases cell viability, inhibits proliferation, colony formation and migration in melanoma cell lines (non-resistant and resistant to vemurafenib, BRAF inhibitor). It also decreased the secretion of pro-tumor interleukin IL-8 in resistant cells. STX140 induced senescence in melanoma cells, that were positive for ß-galactosidase, and there was also increased expression of key genes of senescence pathways (CDKN1A and GADD45A) in resistant melanoma cells treated with the compound. In conclusion, STX140 has been shown to have antitumor potential against melanoma, decreasing its cell viability, inhibiting its proliferation and migration, inducing senescence, decreasing pro-tumor interleukin secretion, with a more pronounced effect on resistant melanoma cell lines

Stx1 and Stx2 subtyping and antimicrobial resistance in Shiga toxin-producing Escherichia coli (STEC) isolates from cattle and sheep feces in the Southeastern region of the State of Goiás, Brazil

ABSTRACT: The present study was aimed at subtyping of Stx1 and Stx2 genes and characterization of antimicrobial resistance in 106 Shiga toxin-producing Escherichia coli (STEC) strains isolated from cattle and sheep feces. PCR was used to determine the subtypes, and the disk-diffusion method was used to evaluate the antimicrobial resistance. Ten antibiotics from five different classes were tested. Among the isolates of bovine origin, two subtypes of Stx1 (Stx1a and Stx1c), and four subtypes of Stx2 (Stx2a, Stx2b, Stx2c, and Stx2d) were identified. In isolates of sheep origin, two subtypes of Stx1 (Stx1a and Stx1c), and four subtypes of Stx2 (Stx2a, Stx2b, Stx2c, and Stx2 g) were identified. The results obtained suggest the presence of high diversity in Stx1 and Stx2 genes. Further, 96.6% (57/59) of bovine fecal strains and 89.4% (42/47) of sheep fecal strains showed resistance to at least one tested antibiotic. In both animal species, most strains were multidrug-resistant (MDR) (67.8% in cattle and 59.6% in sheep), with no significant difference between host animals. Adult animals were eight times more likely to have STEC with greater pathogenic potential. STEC with the highest pathogenic potential were three times more likely to be multidrug-resistant than STEC with the lowest pathogenic potential. The data reported in this study suggests the occurrence of strains with high potential pathogenicity in the region studied. Therefore, the ruminants of this region are carriers of strains that can cause infections in humans.

RESUMO: O presente estudo teve como objetivo subtipar os genes Stx1 e Stx2 e caracterizar a resistência antimicrobiana em 106 isolados de Escherichia coli produtoras de toxinas Shiga (STEC) isoladas de fezes de bovinos e ovinos. A PCR foi utilizada para determinar os subtipos e o método de difusão em disco foi utilizado para avaliar a resistência antimicrobiana. Dez antibióticos de cinco classes diferentes foram testados. Entre os isolados de origem bovina, foram identificados dois subtipos de Stx1 (Stx1a e Stx1c) e quatro subtipos de Stx2 (Stx2a, Stx2b, Stx2c e Stx2d). Nos isolados de origem ovina, foram identificados dois subtipos de Stx1 (Stx1a e Stx1c) e quatro subtipos de Stx2 (Stx2a, Stx2b, Stx2c e Stx2g). Os resultados obtidos sugerem a presença de alta variabilidade nos genes Stx1 e Stx2. Além disso, 96,6% (57/59) dos isolados fecais de bovinos e 89,4% (42/47) dos isolados de ovinos mostraram resistência a pelo menos um antibiótico testado. Em ambas as espécies animais, a maioria das cepas foi multirresistente (MDR) (67,8% em bovinos e 59,6% em ovinos), sem diferença significativa entre as espécies animais do reservatório. Os animais adultos tiveram oito vezes mais chances de apresentar STEC com maior potencial patogênico. STEC com o maior potencial patogênico teve três vezes mais chances de ser multirresistente do que o STEC com o menor potencial patogênico. Os dados relatados neste estudo sugerem a ocorrência de cepas com alto potencial de patogenicidade na região estudada. Portanto, os ruminantes dessa região são hospedeiros de isolados que podem causar infecções em humanos.

Stx1 and Stx2 subtyping and antimicrobial resistance in Shiga toxin-producing Escherichia coli (STEC) isolates from cattle and sheep feces in the Southeastern region of the State of Goiás, Brazil / Subtipagem de Stx1 e Stx2 e resistência antimicrobiana em isolados de Escherichia coli produtoras de toxina Shiga (STEC) de fezes de bovinos e ovinos na região sudeste de Goiás, Brasil

The present study was aimed at subtyping of Stx1 and Stx2 genes and characterization of antimicrobial resistance in 106 Shiga toxin-producing Escherichia coli (STEC) strains isolated from cattle and sheep feces. PCR was used to determine the subtypes, and the disk-diffusion method was used to evaluate the antimicrobial resistance. Ten antibiotics from five different classes were tested. Among the isolates of bovine origin, two subtypes of Stx1 (Stx1a and Stx1c), and four subtypes of Stx2 (Stx2a, Stx2b, Stx2c, and Stx2d) were identified. In isolates of sheep origin, two subtypes of Stx1 (Stx1a and Stx1c), and four subtypes of Stx2 (Stx2a, Stx2b, Stx2c, and Stx2 g) were identified. The results obtained suggest the presence of high diversity in Stx1 and Stx2 genes. Further, 96.6% (57/59) of bovine fecal strains and 89.4% (42/47) of sheep fecal strains showed resistance to at least one tested antibiotic. In both animal species, most strains were multidrug-resistant (MDR) (67.8% in cattle and 59.6% in sheep), with no significant difference between host animals. Adult animals were eight times more likely to have STEC with greater pathogenic potential. STEC with the highest pathogenic potential were three times more likely to be multidrug-resistant than STEC with the lowest pathogenic potential. The data reported in this study suggests the occurrence of strains with high potential pathogenicity in the region studied. Therefore, the ruminants of this region are carriers of strains that can cause infections in humans.(AU)

O presente estudo teve como objetivo subtipar os genes Stx1 e Stx2 e caracterizar a resistência antimicrobiana em 106 isolados de Escherichia coli produtoras de toxinas Shiga (STEC) isoladas de fezes de bovinos e ovinos. A PCR foi utilizada para determinar os subtipos e o método de difusão em disco foi utilizado para avaliar a resistência antimicrobiana. Dez antibióticos de cinco classes diferentes foram testados. Entre os isolados de origem bovina, foram identificados dois subtipos de Stx1 (Stx1a e Stx1c) e quatro subtipos de Stx2 (Stx2a, Stx2b, Stx2c e Stx2d). Nos isolados de origem ovina, foram identificados dois subtipos de Stx1 (Stx1a e Stx1c) e quatro subtipos de Stx2 (Stx2a, Stx2b, Stx2c e Stx2g). Os resultados obtidos sugerem a presença de alta variabilidade nos genes Stx1 e Stx2. Além disso, 96,6% (57/59) dos isolados fecais de bovinos e 89,4% (42/47) dos isolados de ovinos mostraram resistência a pelo menos um antibiótico testado. Em ambas as espécies animais, a maioria das cepas foi multirresistente (MDR) (67,8% em bovinos e 59,6% em ovinos), sem diferença significativa entre as espécies animais do reservatório. Os animais adultos tiveram oito vezes mais chances de apresentar STEC com maior potencial patogênico. STEC com o maior potencial patogênico teve três vezes mais chances de ser multirresistente do que o STEC com o menor potencial patogênico. Os dados relatados neste estudo sugerem a ocorrência de cepas com alto potencial de patogenicidade na região estudada. Portanto, os ruminantes dessa região são hospedeiros de isolados que podem causar infecções em humanos.(AU)

An Stx-EAEC O59:NM[H19] strain isolated from a hemolytic uremic syndrome case in Argentina / Cepa EAEC-Stx O59:NM[H19] aislada de un caso de síndrome urémico hemolítico en Argentina

Abstract Shiga toxin-producing Escherichia coli (STEC) are a heterogeneous group of foodborne pathogens causing a broad spectrum of human disease, from uncomplicated diarrhea to hemolytic uremic syndrome (HUS). In this study, we report an HUS case associated with an O59:NM H19 mstrain, harboring stx2a, iha, lpfAO26, lpfAO113 genes associated with STEC, and aatA, aap, pic, sigA, agg4A genes associated with enteroaggregative E. coli (EAEC), named Stx-EAEC. The strain showed low toxicity on Vero cells, and was resistant to streptomycin and trimethoprim/sulfonamides. The child carried the bacteria for more than 100 days. Since the large outbreak associated with Stx-EAEC O104:H4, many strains with similar profiles have been described. In Germany, an O59:NM[H19] strain, with comparable characteristics to the Argentine strain, was isolated from a bloody diarrhea case. In Argentina, this is the first report of an HUS case associated with a Stx-EAEC infection, and represents a new challenge for the surveillance system. © 2019 Published by Elsevier Espana, S.L.U. on behalf of Asociacion Argentina de Microbiolog´a. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/ licenses/by-nc-nd/4.0/).

Resumen Escherichia coli productor de la toxina Shiga (STEC) es un grupo heterogéneo de patógenos transmitidos por alimentos que causan un amplio espectro de enfermedades humanas, desde diarrea no complicada hasta síndrome urémico hemolítico (SUH). Nosotros informamos de un caso de SUH por O59:NM[H19], que portaba los genes stx2a, iha, lpfAo26, lpfAoii3 asociados con STEC, y los genes aatA, aap, pic, sigA, agg4A de E. coli enteroagregativo (EAEC), llamado EAEC-Stx. La cepa mostró baja citotoxicidad en las células Vero, y fue resistente a estreptomicina y trimetoprima/sulfonamidas. El niño excretó la bacteria durante más de 100 días. Desde el brote asociado con EAEC-Stx O104:H4, se describieron muchas cepas con perfiles similares. En Alemania se aisló una cepa O59:NM[H19] de una diarrea sanguinolenta, con características comparables a la cepa argentina. Este es el primer informe de un caso de SUH asociado a una infección por EAEC-Stx, y representa un nuevo desafío para el sistema de vigilancia. © 2019 Publicado por Elsevier Espana, S.L.U. en nombre de Asociación Argentina de Microbiología. Este es un artículo Open Access bajo la licencia CC BY-NC-ND (http://creativecommons. org/licenses/by-nc-nd/4.0/).

Bioluminescence of Vibrio fischeri: A novel application for PSP quantification

Paralytic Shellfish Poison (PSP) are the most harmful neurotoxins create a serious public health problem. It is important to assess PSP in Shellfish destined for human consumption. However, recommended methods have some limitations for example in the case of Mouse Bioassay (MBA) showed a low sensitivity and reproducibility, and undesirability for ethical reasons; while physico-chemical techniques rest expensive and time-consuming. The main objective of this study, after discovered that PSP inhibited the luminescence of Vibrio fischeri, was the quantification of PSP by using Bioluminescence Inhibition Assay (BIA), and comparing the results obtained with those determined by MBA and LC-MS. Bivalve used were collected from Corniche Martil, Kabila and Oued Laou, along the Mediterranean coast of Morocco in Mars-2015. Results showed a weak correlation between LC-MS and MBA with r = 0.11, while, the correlation between LC-MS and BIA was very strong with r = 0.97, which suggests that, BIA could offer an interesting additional assessment of PSP risk. In addition, after seen its rapidity, ease, reliability, sensitivity, reproducibility and cost effectiveness, it would be eligible to use for monitoring in surveillance programs.

Inhibition of STAT3 signaling induces apoptosis and suppresses growth of lung cancer: good and bad / 한국실험동물학회지

Signal transducer and activator of transcription 3 (STAT3) modulates a variety of genes involved in the regulation of critical functions, including cell proliferation, differentiation, apoptosis, angiogenesis, metastasis, and immunity. For many cancers, elevated levels of STAT3 signaling have been associated with a poor prognosis and the development of chemotherapy resistance. In this study, we investigated the inhibitory effects of a novel small-molecule inhibitor of STAT3, STX-0119, on the cell viability and survival of human lung cancer cells. STX-0119 inhibited activated STAT3 and the expression of STAT3-regulated oncoproteins such as c-Myc, cyclin D1, and survivin in lung cancer cells. STX-0119 also decreased the amount of STAT3 in the nuclear fraction as well as induced apoptosis of these lung cancer cell lines as evidenced by increases in apoptotic cells (Annexin V positive) and poly (ADP-ribose) polymerase (PARP) cleavage. The efficacy of STX-0119 in a mouse xenograft model was confirmed. However, a hematological side effect, which had not been previously reported, was observed. The level of white blood cells was significantly lowered when treated at the dose at which STX-0119 alone showed a significant tumor-suppressive effect. In conclusion, we suggest that STX-0119 may be a potent therapeutic agent against lung cancer. Consideration of the side effect suggests, it is necessary to study whether low-dose STX-0119 is effective for lung treatment with a combination of classic lung cancer therapeutics.

Molecular Detection of the Virulence Genes in Escherichia coli Isolated from Healthy and Diarrheic Calves in Southern Iraq

Aim: To investigate the stx1, stx2, hly, cnf2, sfa/foc, afaI, papC, and afaC virulence-associated genes of pathogenic Escherichia coli, isolated from diarrheic and non-diarrheic calves. Materials and Methods: The genes to be investigated were first isolated from the stool samples obtained from 150 diarrheic and non-diarrheic calves, between the ages of one day and six months, during the period 2016 to 2017. Rectal swabs were aseptically and randomly collected from several herds, from different regions in the province of Basra. Results of Research: The polymerase chain reaction (PCR) results showed that pathogenic E. coli were detected in a total of 34 out of 41 (82.9%) distributed as 23 out of 26 (88.5%) and 11 out of 15 (73.3%) of the diarrheagenic and non-diarrheagenic calves, respectively. The results also showed that stx1, hlyA, and stx2genes showed a higher incidence of distribution in both diarrheagenic and non-diarrheagenic calves, in a percentage rate of 69.6%, 65.2%, 56.5% and 63.6%, 63.6%, 45.5%, respectively. Moreover, eight different virulence gene profiles were established in the present study. Most of the isolates analyzed had at least two or three gene arrangements and only four isolates were seen in a combination of four genes stx1, stx2, hlyA, and afaI. Conclusion: It is concluded that E. coli isolates from healthy and diarrheic calves that carried various virulence genes, of which the most frequent were stx1, stx2, and hlyA. A high percentage of these isolates are found in both diarrheic and non-diarrheic calves.

Distribution of the stx1 and stx2 genes in Escherichia coli isolated from milk cattle according to season, age, and production scale in southwestern region of Goiás, Brazil / Distribuição dos genes stx1 e stx2 em Escherichia coli isoladas de bovinos de leite de acordo com a estação, idade e escala de produção na região sudoeste de Goiás, Brasil

This study determined the distribution of stx1 and stx2 genes in Escherichia coli isolated from dairy herds with regard to animal age, season, and farm production-scale, and analyzed the phylogenetic distribution of the groups A, B1, B2, and D of 276 isolates of bovine feces Shiga toxin-producing E. coli (STEC). The stx1 profile was the most common, detected in 20.4% (202/990) of the isolates, followed by stx2 (4.54%, 45/990) and stx1+stx2 (2.92%, 29/990). The stx1 gene was detected more frequently in calves than in adult animals. In the dry season (winter), the presence of stx1+stx2 profile in cattle feces was higher than in the rainy season (summer), while no significant changes were observed between seasons for the stx1 and stx2 profiles. The most predominant phylogenetic groups in adult animals were B1, A, and D, while groups A and B1 prevailed in calves. Our data highlight the importance of identifying STEC reservoirs, since 7.5% of the tested isolates were positive for stx2, the main profile responsible for the hemolytic-uremic syndrome (HUS). Moreover, these microorganisms are adapted to survive even in hostile environments and can contaminate the food production chain, posing a significant risk to consumers of animal products.(AU)

Esse estudo determinou a distribuição dos genes stx1 e stx2 em Escherichia coli isolados de rebanhos leiteiros em relação a idade, estação e produção, e analisaram a distribuição filogenética dos grupos A, B1, B2 e D de 276 E. coli produtoras de toxina Shiga (STEC). O perfil stx1 foi mais comum, detectado em 20,4% (202/990) dos isolados, seguido de stx2 (4,54%, 45/990) e stx1+stx2 (2,92%, 29/990). O gene stx1 foi detectado mais frequentemente em bezerros que animais adultos. No período de seca (inverno), a presença do perfil stx1+stx2 nas fezes dos bovinos foi mais prevalente que no período chuvoso (verão), apesar de não haver diferença significativa entre estações para os perfis stx1 e stx2. Os grupos filogenéticos mais predominantes em animais adultos foram B1, A e D, enquanto grupos A e B2 prevaleceram em bezerros. Nossos dados enfatizam a importância de se detectar reservatórios de STEC já que 7,5% dos isolados testados foram positivos para stx2, o perfil mais prevalente em casos de síndrome hemolítica-urêmica. Ademais, esses microorganismos são adaptados à sobreviver em ambientes hostis e contaminam a cadeia alimentar, levando a risco significativo para consumidores de alimentos de origem animal.(AU)

Microbiological and serological control of Escherichia coli O157: H7 in kindergarten staff in Buenos Aires city and suburban areas

Shiga toxin (Stx)-producing Escherichia coli (STEC) infections are implicated in the development of the life-threatening hemolytic-uremic syndrome (HUS). Despite the magnitude of the social and economic problems caused by HUS, no licensed vaccine or effective therapy is currently available for human use. Prevention of STEC infections continues being the most important measure to reduce HUS incidence. This is especially true for Argentina where HUS incidence among children is extremely high and shows an endemic pattern. The aim of this work was to investigate serologically adult staff of kindergartens in Buenos Aires city and suburban areas in order to detect possible carriers, and to educate personnel about good practices to reduce HUS transmission. We also assessed the microbiological quality of water and meal samples from the same kindergartens. We tested 67 healthy adults, 13 water supplies and 6 meals belonging to 6 public kindergartens. We analysed hand swabs for isolation of STEC and serum samples for the presence of antibodies against Stx and lipopolysaccharide (LPS) of O157 serogroup. We identified 46 Stx2-positive individuals, but only 7 for O157 LPS. No presence of STEC pathogens was detected in hands of staff, water or meal samples.

Las infecciones bacterianas con Escherichia coli productor de toxina Shiga (Stx) (STEC) están implicadas en el desarrollo del síndrome urémico hemolítico (SUH). A pesar de la magnitud del problema social y económico causado por el SUH, actualmente no existe un tratamiento específico o una vacuna eficaz para uso humano. Por lo tanto, la prevención de las infecciones por STEC es la tarea central para reducir la incidencia del SUH. Esto es especialmente cierto para Argentina en donde el SUH muestra un comportamiento endémico y presenta una incidencia extremadamente alta entre los niños. En efecto, la mediana de casos notificados en menores de 5 años para el periodo 2010-2015 fue 306, mientras que la tasa de notificación fue 8.5 casos cada 100 000 menores/año (http://www.msal.gob.ar/images/stories/boletines/boletin_integrado_vigilancia_N335-SE45.pdf). El objetivo de este trabajo fue analizar serológicamente al personal adulto de jardines de infantes de la ciudad de Buenos Aires y el área suburbana con el fin de detectar portadores, y brindarles formación sobre las buenas prácticas para reducir la transmisión de infecciones con STEC y así evitar el SUH. También se evaluó la calidad microbiológica de las muestras de agua y de la comida elaborada en los mismos jardines. Hemos estudiado 67 adultos, a través del hisopado de manos para la búsqueda de STEC y suero para la presencia de anticuerpos contra Stx y el lipopolisacárido (LPS) de serogrupo O157. También se analizaron 13 suministros de agua y 6 muestras de comida pertenecientes a 6 jardines de infantes públicos. Se identificaron 46 individuos positivos para Stx2, pero solo 7 para LPS-O157. No se detectó presencia de patógenos STEC en las muestras de las manos del personal, ni en los reservorios de agua o muestras de comida.

Association between phage-mediated shiga toxin and molecular distribution of CRISPR in Escherichia coli O26 : H11 or NM / 中华流行病学杂志

Objective To investigate the association between phage-mediated shiga toxin and molecular distribution of CRISPR in Escherichia (E.) coli O26:H11 or NM.Methods A total of 135 E.coli O26:H11 or NM strains were collected from NCBI database.Software CRT and CRISPR Finder were used to extract CRISPR and Excel was used to assign the spacer of unique number and type CRISPR.And the relationship between CRISPR and stx phage was analyzed.Results All the 135 E.coli O26:H11 or NM strains had the CRISPR.For CRISPRI,CRISPR2.1,CRISPR2.2 and CRISPR3-4,19,22,1 and 1 subtypes were found,respectively.According to the four CRISPR sites,the strains could be divided into 40 subtypes.Stx-phage was only observed in the group C of CRISPR.Compared with E.coli of stx-phage negative,E.coli with stx-phage harbored more spacers.Conclusions CRISPR loci was extensively existed in E.coli O26:H11 or NM,and many subtypes were found in these strains.The presence of stx-phage was related to the molecular distribution of CRISPR in E.coli O26:H11 or NM.CRISPR might be a valuable biomarker to identify strains with high virulent potential.

Association between phage-mediated shiga toxin and molecular distribution of CRISPR in Escherichia coli O26 : H11 or NM / 中华流行病学杂志

Objective To investigate the association between phage-mediated shiga toxin and molecular distribution of CRISPR in Escherichia (E.) coli O26:H11 or NM.Methods A total of 135 E.coli O26:H11 or NM strains were collected from NCBI database.Software CRT and CRISPR Finder were used to extract CRISPR and Excel was used to assign the spacer of unique number and type CRISPR.And the relationship between CRISPR and stx phage was analyzed.Results All the 135 E.coli O26:H11 or NM strains had the CRISPR.For CRISPRI,CRISPR2.1,CRISPR2.2 and CRISPR3-4,19,22,1 and 1 subtypes were found,respectively.According to the four CRISPR sites,the strains could be divided into 40 subtypes.Stx-phage was only observed in the group C of CRISPR.Compared with E.coli of stx-phage negative,E.coli with stx-phage harbored more spacers.Conclusions CRISPR loci was extensively existed in E.coli O26:H11 or NM,and many subtypes were found in these strains.The presence of stx-phage was related to the molecular distribution of CRISPR in E.coli O26:H11 or NM.CRISPR might be a valuable biomarker to identify strains with high virulent potential.

Serotipos, perfiles de virulencia y subtipos de stx en Escherichia coli productor de toxina Shiga aislados de productos de pollo / Serotypes, virulence profiles and stx subtypes of Shigatoxigenic Escherichia coli isolated from chicken derived products

Shigatoxigenic Escherichia coli (STEC) is a foodborne pathogen that causes hemolytic uremic syndrome (HUS) and the consumption of chicken products has been related to some HUS cases. We performed a non-selective isolation and characterization of STEC strains from retail chicken products. STEC isolates were characterized according to the presence of stx1, stx2, eae, saa and ehxA; stx subtypes and serotypes. Most of them carried stx2, showing subtypes associated with severe human disease. Although reported in other avian species, the stx2f subtype was not detected. The isolates corresponded to different serotypes and some of them, such as O22:H8, O113:H21, O130:H11, O171:H2 and O178:H19, have also been identified among STEC isolated from patients suffering from diarrhea, hemorrhagic colitis, HUS, as well as from cattle. Considering the virulence profiles and serotypes identified, our results indicate that raw chicken products, especially hamburgers sold at butcheries, can be vehicles for high-risk STEC strains.

Escherichia coli productor de toxina de Shiga (STEC) es un patógeno transmitido por alimentos que causa el síndrome urémico hemolítico (SUH). Algunos casos de SUH están relacionados con el consumo de productos de pollo. Se realizó el aislamiento no selectivo y la caracterización de cepas STEC provenientes de productos de pollo atendiendo a la presencia de stx1, stx2, eae, saa y ehxA, subtipos de stx y serotipos. La mayoría de los aislamientos portaba stx2 y subtipos de stx asociados con enfermedades graves en humanos. Aunque se ha detectado en otras especies aviares, el subtipo stx2f no se encontró. Se detectaron diferentes serotipos, entre ellos O22:H8, O113:H21, O130:H11, O171:H2 y O178:H19, también identificados como STEC aislados de pacientes con diarrea, colitis hemorrágica y SUH, y de ganado bovino. Teniendo en cuenta los perfiles de virulencia y los serotipos identificados, nuestros resultados indican que los productos de pollo crudos, especialmente las hamburguesas que se venden en las carnicerías, pueden ser vehículos de cepas STEC de alto riesgo.

Establishment of a double-antibody sandwich ELISA for the detection of shiga toxin typeⅡin shiga toxin-producing Escherichia coli infection / 中华微生物学和免疫学杂志

Objective To establish a double-antibody sandwich ELISA for the rapid detection of shiga toxin typeⅡ ( StxⅡ) in shiga toxin-producing Escherichia coli ( STEC) infection. Methods A pool of murine hybridomas was used to screen out the optimal antibody pair for the establishment of double-anti-body sandwich ELISA. The established ELISA system was used to detect StxⅡin the culture supernatants of 16 clinical strains of STEC. Specificity and sensitivity of the established ELISA system were also evaluated. Results Two antibodies, S2D8 and S2C6, were successfully screened out, based on which the double-anti-body sandwich ELISA was set up. StxⅡand its variants rather than StxⅠwas detected in the culture super-natants of STEC with a lowest detection limit of 4 ng/ml. Its performance was consistent with that of commer-cial colloidal gold test kit, indicating the characteristics of good specificity and sensitivity. Conclusion The S2D8/S2C6-based ELISA laid a foundation for researches which designates the shiga toxin as a potential can-didate on the diagnosis and therapy of STEC infection.

Alterações na morfologia e na viabilidade no desenvolvimento de embriões bovinos fecundados in vitro com sêmen contaminado experimentalmente à Escherichia coli produtora da toxina Shiga stx2 / Changes in morphology and viability on the development of bovine embryos in vitro fertilized with experimentally contaminated semen to Escherichia coli Shiga toxin producing stx2

O objetivo deste trabalho foi avaliar, por meio de microscopia óptica e eletrônica de transmissão, as alterações na morfologia e a viabilidade do desenvolvimento de embriões bovinos fecundados com sêmen contaminado experimentalmente à Escherichia coli produtora da toxina shiga stx2 (STEC). Para tanto, oócitos foram aspirados de ovários de vacas abatidas e selecionados para maturação in vitro. Após 20-24 horas de maturação, os oócitos foram divididos em 2 grupos. Sendo o primeiro grupo o controle (n = 418), fertilizado com sêmen testado e sem nenhum tipo de contaminante e o segundo, o grupo contaminado (n = 415), fertilizado com sêmen exposto a STEC. Cada sêmen foi tratado pela técnica de gradiente descontínuo de Percoll. Após o período de fecundação, os embriões foram avaliados quanto a sua morfologia e viabilidade, com o auxílio da microscopia óptica e eletrônica. Na ava liação morfológica, os oócitos fecundados com o sêmen contaminado apresentaram retração citoplasmática, falhas na divisão, assimetria de blastômeros, ooplasma granuloso, coloração castanho-escuro, formação de vacúolos, degeneração e rompimento da zona pelúcida. Essas alterações não foram observadas no grupo controle. A avaliação de todos oócitos incluídos mostrou taxas de clivagem de 70,3 e 52,8%, respectivamente, para embriões controle e contaminado (p = 0,0001). Após o 5° dia de desenvolvimento embrionário foram observadas 44,7% de mórulas no grupo controle e 22,4% no grupo contaminado, apresentando diferença significativa (p=0,0001). A presença da STEC interfere na taxa de clivagem dos embriões e também inviabiliza e provoca queda no desenvolvimento embrionário ao estádio de mórula, além de causar alterações morfológicas durante esse desenvolvimento.(AU)

The objective of this study was to evaluate by optical microscopy and transmission electron, changes in morphology and viability of the development of bovine embryos, fertilized with semen experimentally contaminated (STEC). Oocytes were aspirated from ovaries of slaughtered cows and the intact zona pellucida were selected and matured. After 20-24 hours of maturation, the oocytes were divided into 2 groups. The first, control group (n = 4l8),fertilized with semen tested and without any type of contaminant and the second, the infected group (n = 415), fertilized with sperm exposed to STEC. Both semen were treated by the technique of discontinuous Percoll gradient. After the period of fertilization, embryos were evaluated for their morphology and viability by optical and electron microscopy. In morphologic evaluation, the oocytes fertilized with contaminated semen showed cytoplasmic shrinkage, gaps in the division, asymmetry of blastomeres, ooplasm grainy, dark brown color, vacuoles formation, degeneration and zona pellucid disruption. These changes were not observed in the control group. The cleavage rate was 70.3 and 52.8%, respectively, for control and infected groups, significant differences (p = 0.0001). After the 5th day of embryonic development, where it was observed 44.7% of morula in the control group, and 22.4% in the contaminated group, showing a significant difference (p = 0.0001). The presence of STEC interferes with the cleavage rate of embryos and also prevents and causes a decline in embryonic development to the morula stage and cause morphological changes during this development.(AU)

Development of a multiplex loop-mediated isothermal amplification assay to detect shiga toxin-producing Escherichia coli in cattle

A multiplex loop-mediated isothermal amplification (mLAMP) assay was developed for simultaneous detection of the stx1 and stx2 genes and applied for detection of shiga toxin-producing Escherichia coli (STEC) in cattle farm samples. Two target genes were distinguished based on T m values of 85.03 +/- 0.54degrees C for stx1 and 87.47 +/- 0.35degrees C for stx2. The mLAMP assay was specific (100% inclusivity and exclusivity), sensitive (with a detection limit as low as 10 fg/microL), and quantifiable (R 2 = 0.9313). The efficacy and sensitivity were measured to evaluate applicability of the mLAMP assay to cattle farm samples. A total of 12 (12/253; 4.7%) and 17 (17/253; 6.7%) STEC O157, and 11 (11/236; 4.7%) non-O157 STEC strains were isolated from cattle farm samples by conventional selective culture, immunomagnetic separation, and PCR-based culture methods, respectively. The coinciding multiplex PCR and mLAMP results for the types of shiga toxin revealed the value of the mLAMP assay in terms of accuracy and rapidity for characterizing shiga toxin genes. Furthermore, the high detection rate of specific genes from enrichment broth samples indicates the potential utility of this assay as a screening method for detecting STEC in cattle farm samples.

Regulatory effects of Stx phage on the T3SS in E.coli O157 ∶H7 / 中华微生物学和免疫学杂志

Objective To investigate the effects of shiga toxin ( Stx ) phage on the expression of type Ⅲsecretion system (T3SS) in E.coli O157 ∶H7.Methods A standard E.coli O157 ∶H7 strain, EDL933 and a natural Stx phage defective mutant of EDL 933 strain, TUV93-0 were used for this study .The expression of T3SS proteins was compared between EDL 933 and TUV93-0 strains.The expression of five operons ( LEE1-LEE5 ) was evaluated by measuring the green fluorescent protein ( GFP ) in five different plasmids with LEE1-LEE5 promoters, respectively.Results The expression of T3SS proteins in TUV93-0 mutant were significantly increased than those in EDL 933 strain.Moreover, the expression of LEE1, LEE2 and LEE5 were also increased in TUV93-0 mutant.Conclusion The deletion of Stx phage might enhance T3SS expression through the regulation of LEE 1.

Molecular characterization of Shiga Like Toxin-Producing Escherichia Coli (STEC) isolates from broiler and local variety of poultry.

Escherichia coli isolates from different samples of droppings collected from the different farms of broiler and local poultry were characterized to confirm the virulence. E. coli isolates recovered from different farms were examined for presence of genes encoding patho groups such as shiga like toxin producing Escherichia coli (STEC), (stx1/stx2) by Duplex PCR and then analysed the PCR Amplicons by AGE. The three and four isolates of E. coli recovered from local and boiler poultry were STEC because of presence of the stx1 and stx2 genes. Presence of stx1 and stx2 genes clearly indicated these as prime cause of pathogenecity. Further, demonstration of STEC in poultry becomes a public health concern, as poultry are potential reservoir of such agents, which may cause extra intestinal diseases like haemolytic uremic syndrome and thrombocytopenic purpurea by stx1 &2 and these toxins kill vascular endothelial cells.

PCR detection of ‘STX 1’ and ‘STX 2’ toxigenic genes in multiple antibiotic resistant escherichia coli population and phenotypic detection of ESBL producing escherichia coli. isolates from local variety of poultry.

PCR detection of ‘stx 1’ and ‘stx 2’ toxigenic genes in multiple antibiotic resistant Escherichia coli population and Phenotypic detection of ESBL producing Escherichia coli isolated from traditional local variety of poultry was conducted The study revealed that out of 30 samples collected 20 were positive for E.coli All the 20 isolates were subjected for the detection of 2 toxin genes (stx1 & stx2 genes) by PCR. Only 3 isolates (L3, L4 & L5) gave rise to PCR product against its specific primers of stx1. All the isolates were negative for the presence of stx2 gene. Thus 15% of E.coli population under this study is potential isolates and indicates that healthy retail poultry birds are the carrier of E.coli pathogenic strains. The poultry birds may therefore, be considered as a major reservoir of E.coli.