Enterotoxin gene profiles of Staphylococcus aureus isolated from environment and patients in a hospital in Shanghai from 2018 to 2021 / 上海预防医学

ObjectiveTo investigate the prevalence of Staphylococcus aureus in a hospital in Jiading District， Shanghai， and to determine the enterotoxin gene profiles of Staphylococcus aureus isolated from patients and environment. MethodsSpecimens were collected from environment and patients from a hospital for Staphylococcus aureus isolation and identification. Furthermore， enterotoxin genes （SEA‒SEE） of Staphylococcus aureus were detected. ResultsA total of 54 Staphylococcus aureus strains were isolated from 780 hospital environmental specimens from 2018 to 2021， with a prevalence of 6.92%. In the armrests in the wards， patient’s pillows/quilts， and bedside cupboards， the prevalence was determined to be 20.00%， 20.00% and 16.67%， respectively. In contrast， in the computer’s mouse and keyboard and work clothes of physicians and nurses， the prevalence was 17.42% and 16.67%， respectively. Meanwhile， from 2018 to 2021， a total of 75 strains were collected from patients， of which 36.00%， 14.67% and 14.67% were from the departments of intensive care medicine （ICU）， neurosurgery and orthopedics， respectively. The prevalence of Staphylococcus aureus enterotoxin genes were 48.15% and 61.33% in the environment and patients， respectively. Furthermore， the prevalence of SEA， SEB， SEC， SED， and SEE genes were 14.67%， 41.33%， 9.33%， 1.33%， 1.33% in patients， respectively ， whereas 20.37%， 25.93%， 1.85 %， 1.85% and 0% in environmental specimens， respectively. In the environmental specimens isolated from comprehensive ICU， the prevalence of enterotoxin genes was 77.27%. In the patient's specimens， Staphylococcus aureus was mostly isolated in sputum. Additionally， the prevalence of enterotoxin genes was high in the patients of departments of respiratory medicine， ICU， and orthopedics. ConclusionPrevalence of Staphylococcus aureus remains moderate in the hospital environment. Enterotoxin genes of Staphylococcus aureus are common， with seb gene as the most common gene， followed by SEA gene. It warrants strengthening the disinfection and control of Staphylococcus aureus in the hospital， especially in the ICU.

Potentially pathogenic Staphylococcus aureus and Listeria spp. in Brazilian unpasteurized cheese production / Staphylococcus aureus e Listeria spp. potencialmente patogênicos na produção de queijos não pasteurizados

This study aimed to identify potentially pathogenic microorganisms (Listeria innocua, L. seeligeri, L. ivanovii, L. monocytogenes, Staphylococcus aureus, and several virulence genes) in unpasteurized cheese production in the northeastern region of the state of São Paulo, Brazil. Listeria species were detected in 68 (64.14%) out of 106 samples of bovine feces, swabs from milkers' and cheese handlers' hands, milking buckets, raw milk, whey, water, cheese processing surface,s and utensils. All the samples collected at one farm were contaminated with Listeria spp. L. innocua, L. seeligeri, L. ivanovii, or L. monocytogenes were not detected in the samples collected in this study. A set of 391 Staphylococcus spp. isolates were obtained in these samples, from which 60 (15.31%) were identified as S. aureus using PCR (Polymerase Chain Reaction). S. aureus carrying virulence genes (eta, hlg, seg, seh, sei) were detected in milk, in swabs from cheese handler's hands, whey, milk, sieves, buckets, and cheese. The hlg gene (encodes gamma hemolysin) was detected in all the S. aureus isolates. These findings show that poor hygienic practice is associated with a higher risk of pathogenic bacteria in milk or cheese, providing useful information for public health authorities to increase food safety surveillance and prevent the dissemination of pathogens.

O objetivo desse estudo foi identificar microrganismos potencialmente patogênicos (Listeria innocua, L. seeligeri, L. ivanovii, L. monocytogenes, Staphylococcus aureus e diversos genes de virulência) na produção de queijos de leite cru na região noroeste do Estado de São Paulo, Brasil. Listeria foram detectadas em 68 (64,14%) das 106 amostras obtidas de fezes bovinas, suabes das mãos de ordenhadores e queijeiros, baldes, leite cru, soro, água, superfícies e utensílios da produção de queijos. Todas as amostras coletadas em uma fazenda estavam contaminadas com Listeria spp. L. innocua, L. seeligeri, L. ivanovii, e L. monocytogenes não foram detectadas nas amostras coletadas nesse estudo. Um conjunto de 391 isolados de Staphylococcus spp. foram obtidos das amostras, e desses 60 (15,31%) foram identificados como S. aureus pela PCR (Polymerase Chain Reaction). S. aureus contendo genes de virulência (eta, hlg, seg, seh, sei) foram detectados em leite, mãos dos ordenhadores, soro, utensílios e queijos. O gene hlg (gama-hemolisina)foi detectado em todos os isolados de S. aureus.Esses resultados demonstram que práticas inadequadas de higiene estão associadas com um maior risco da presença de bactérias patogênicas no leite e queijos crus, fornecendo informações para as autoridades de saúde pública para incrementarem a vigilância e prevenirem a disseminação de patógenos.

Genomic characterization, antimicrobial resistance profiles, enterotoxin, and biofilm production of methicillin-resistant Staphylococcus aureus isolated from clinical and animal products origins in Eastern Turkey / Caracterização genômica perfis de resistência antimicrobiana, produção de enterotoxinas e biofilme Staphylococcus aureus resistente à meticilina isolado de origem clínica e de produtos de origem animal no leste da Turquia

Staphylococcus aureus is an opportunistic and ubiquitous pathogen found in the skin, nares, and mucosal membranes of mammals. Increasing resistance to antimicrobials including methicillin has become an important public concern. One hundred and eight (108) S. aureus strains isolated from a total of 572 clinical and animal products samples, were investigated for their biofilm capability, methicillin resistance, enterotoxin genes, and genetic diversity. Although only one strain isolated from raw retail was found as a strong biofilm producer, the percentage of antimicrobial resistance pattern was relatively higher. 17.59% of S. aureus strains tested in this study were resistant to cefoxitin and identified as methicillin-resistant S. aureus (MRSA) isolates. mecA and mecC harboring S. aureus strains were detected at a rate of 2.79% and 0.93%, respectively. In addition, staphylococcal enterotoxin genes including Sea, Seb, Sec, and Sed genes were found to be 18.5%, 32.4%, 6.5% and 3.7%, respectively. The phylogenetic relationship among the isolates showed relationship between joint calf and cow milk isolates. Multi locus sequence typing (MLST) revealed three different sequence types (STs) including ST84, ST829, and ST6238. These findings highlight the development and spread of MRSA strains with zoonotic potential in animals and the food chain throughout the world.

Staphylococcus aureus é um patógeno dúctil e ubíquo encontrado na pele, narinas e membranas mucosas de mamíferos. O aumento da resistência aos antimicrobianos, incluindo a meticilina, tornou-se uma importante preocupação pública. Cento e oito (108) cepas de S. aureus isoladas de um total de 572 amostras clínicas e de produtos animais foram investigadas por sua capacidade de biofilme, resistência à meticilina, genes de enterotoxinas e diversidade genética. Embora apenas uma cepa isolada do cru tenha sido encontrada como forte produtora de biofilme, a porcentagem do padrão de resistência antimicrobiana foi relativamente maior. Parte das cepas (17,59%) de S. aureus testadas neste estudo eram resistentes à cefoxitina e identificadas como isolados de MRSA. mecA e mecC abrigando cepas de S. aureus foram detectados a uma taxa de 2,79% e 0,93%, respectivamente. Além disso, verificou-se que os genes da enterotoxina estafilocócica, incluindo os genes Sea, Seb, Sec e Sed, eram 18,5%, 32,4%, 6,5% e 3,7%, respectivamente. A relação filogenética entre os isolados mostrou relação entre os isolados de bezerro e leite de vaca. A tipagem de sequência multiloco (MLST) revelou três tipos de sequência diferentes (STs), incluindo ST84, ST829 e ST6238. Essas descobertas destacam o desenvolvimento e a disseminação de cepas de MRSA com potencial zoonótico em animais e na cadeia alimentar em todo o mundo.

Genomic characterization, antimicrobial resistance profiles, enterotoxin, and biofilm production of methicillin-resistant Staphylococcus aureus isolated from clinical and animal products origins in Eastern Turkey

ABSTRACT: Staphylococcus aureus is an opportunistic and ubiquitous pathogen found in the skin, nares, and mucosal membranes of mammals. Increasing resistance to antimicrobials including methicillin has become an important public concern. One hundred and eight (108) S. aureus strains isolated from a total of 572 clinical and animal products samples, were investigated for their biofilm capability, methicillin resistance, enterotoxin genes, and genetic diversity. Although only one strain isolated from raw retail was found as a strong biofilm producer, the percentage of antimicrobial resistance pattern was relatively higher. 17.59% of S. aureus strains tested in this study were resistant to cefoxitin and identified as methicillin-resistant S. aureus (MRSA) isolates. mecA and mecC harboring S. aureus strains were detected at a rate of 2.79% and 0.93%, respectively. In addition, staphylococcal enterotoxin genes including Sea, Seb, Sec, and Sed genes were found to be 18.5%, 32.4%, 6.5% and 3.7%, respectively. The phylogenetic relationship among the isolates showed relationship between joint calf and cow milk isolates. Multi locus sequence typing (MLST) revealed three different sequence types (STs) including ST84, ST829, and ST6238. These findings highlight the development and spread of MRSA strains with zoonotic potential in animals and the food chain throughout the world.

RESUMO: Staphylococcus aureus é um patógeno dúctil e ubíquo encontrado na pele, narinas e membranas mucosas de mamíferos. O aumento da resistência aos antimicrobianos, incluindo a meticilina, tornou-se uma importante preocupação pública. Cento e oito (108) cepas de S. aureus isoladas de um total de 572 amostras clínicas e de produtos animais foram investigadas por sua capacidade de biofilme, resistência à meticilina, genes de enterotoxinas e diversidade genética. Embora apenas uma cepa isolada do cru tenha sido encontrada como forte produtora de biofilme, a porcentagem do padrão de resistência antimicrobiana foi relativamente maior. Parte das cepas (17,59%) de S. aureus testadas neste estudo eram resistentes à cefoxitina e identificadas como isolados de MRSA. mecA e mecC abrigando cepas de S. aureus foram detectados a uma taxa de 2,79% e 0,93%, respectivamente. Além disso, verificou-se que os genes da enterotoxina estafilocócica, incluindo os genes Sea, Seb, Sec e Sed, eram 18,5%, 32,4%, 6,5% e 3,7%, respectivamente. A relação filogenética entre os isolados mostrou relação entre os isolados de bezerro e leite de vaca. A tipagem de sequência multiloco (MLST) revelou três tipos de sequência diferentes (STs), incluindo ST84, ST829 e ST6238. Essas descobertas destacam o desenvolvimento e a disseminação de cepas de MRSA com potencial zoonótico em animais e na cadeia alimentar em todo o mundo.

Perfil del riesgo de brotes alimentarios por intoxicación estafilocócica en Cuba / Risk profile of staphylococcal food poisoning outbreaks in Cuba

Introducción: Staphylococcus ocasiona con frecuencia intoxicaciones alimentarias; en Cuba es una de las principales causas de brotes. Objetivo: analizar el perfil del riesgo de brotes alimentarios por Staphylococcus en Cuba. Métodos: Se realizó un estudio observacional analítico sobre los factores higiénicos y epidemiológicos asociados al riesgo de la intoxicación alimentaria por Staphylococcus en Cuba, en el Instituto Nacional de Higiene Epidemiología y Microbiología, durante el periodo de enero a noviembre de 2018. La información se obtuvo mediante revisión bibliográfica sistémica, análisis de datos del Laboratorio de Referencia Nacional en Microbiología Sanitaria y informes de brotes de la Dirección Nacional de Salud Ambiental. Se estimó el riesgo microbiológico mediante el programa semicuantitativo Ross-Sumner. Resultados: Se identificó como principal peligro Stahylococcus aureus, productores de enterotoxina A y la determinación de aislamientos resistentes a los antimicrobianos, como Stahylococcus aureus meticilina resistentes. Los alimentos más implicados fueron los productos de repostería y la inocuidad se afectó en mayor frecuencia por la contaminación cruzada en el 31,4 por ciento brotes y la inadecuada conservación en 46,1 por ciento. La predicción de personas que enferman por año en la población de interés fue de 6 260. Conclusiones: El riesgo de la ocurrencia de brotes por Staphylococcus se estimó como alto; la vigilancia se recomienda en alimentos que requieren manipulación directa y no se aplica tratamiento térmico antes del consumo, con gestiones de riesgo dirigidas a productores y consumidores(AU)

Introduction: Staphylococcus is a frequent cause of food poisoning. In Cuba it is one of the main causes of outbreaks. Objective: Analyze the risk profile of staphylococcal food poisoning outbreaks in Cuba. Methods: An observational analytical study was conducted about hygienic and epidemiological factors associated to the risk for staphylococcal food poisoning in Cuba. The study was carried out at the National Institute of Hygiene, Epidemiology and Microbiology from January to November 2018. The information was obtained from a systematic bibliographic review, analysis of data from the Medical Microbiology National Reference Laboratory, and outbreak reports from the National Environmental Health Division. Microbiological risk was estimated with Ross-Sumner semi-quantitative software. Results: The main hazard identified was Staphylococcus aureus, enterotoxin A producers and determination of antimicrobial resistant isolates like methicillin-resistant Staphylococcus aureus. The food items most commonly involved were sweets, and safety was most frequently affected by cross-contamination in 31.4 percent of the outbreaks and inadequate preservation in 46.1 percent. Prediction of members of the population of interest becoming ill every year was 6 260. Conclusions: Risk for the occurrence of staphylococcal food poisoning outbreaks was considered to be high; surveillance is recommended of food items requiring direct manipulation and appropriate thermal treatment is not applied before consumption, with risk management actions aimed at manufacturers and consumers(AU)

Detection of virulence factors in coagulase-negative Staphylococcus spp. strains isolated from Emmental cheese / Detecção de fatores de virulência em cepas de Staphylococcus spp. coagulase negativos isoladas de queijo Emmental

Food prepared with products derived from animals are involved in most cases of staphylococcal poisoning; therefore, the research of Staphylococcus spp. in Emmental cheese is more applicable. The objective of this study was to identify coagulase-negative Staphylococcus spp. (CNS) in cheese using biochemical and molecular techniques to detect the presence of nine genes responsible for the production of enterotoxins. From 180 samples analyzed, 204 CNS strains were obtained and identified as being 46 (22.6%) S. saprophyticus strains, 27 (13.2%) S. hominis spp. hominis strains, 22 (10.8%) S. sciuri strains, 21 (10.3%) S. xylosus strains, 19 (9.3%) S. epidermidis strains, 19 (9.3%) S. haemolyticus strains, 17 (8.3%) S. lentus strains, 17 (8.3%) S. warneri strains, 11 (5.4%) S. equorum strains and 5 (2.5%) S. cohnni . Using the PCRm protocol, 14 (6.9%) strains with the presence of the genes on the enterotoxin E (SEE)11 (78.6%), J (SEJ) 1 (7%), C (SEC) 1 (7%) and I (SEI) 1 (7%) were detected. Based on the results, the type of package is not interfered of growth and isolated that Staphylococcus spp. in cheese. It was observed that bacteria capacity to produce coagulase cannot be understood as an indicative of enterotoxigenicity; therefore, the CNS should be considered as a target of importance in the epidemiology of staphylococcal intoxications. It can be concluded that CNS need to be included in bacterial foodborne disease research, since the genes responsible for the production of toxins were detected and none of the studied samples presented Staphylococcus spp. counting above the limits allowed by legislation.(AU)

Os alimentos preparados com produtos de origem animal são os mais envolvidos em casos de intoxicação alimentar estafilocócica; portanto a pesquisa do Staphylococcus spp. em queijos tipo Emmental é relevante. O objetivo foi isolar e identificar espécies de Staphylococcus coagulase negativas (CNS)de queijo Emmental acondicionado em vários tipos de embalagem, por meio de técnicas bacteriológicas e bioquímicas e detectar, por PCR, a presença de nove genes responsáveis pela produção de enterotoxinas. Das 180 amostras, foram isoladas 204 cepas de CNS, que foram identificadas por provas bioquímicas como: 46 (22,6%) S. saprophyticus, 27 (13,2%) S. hominis spp. hominis, 22 (10,8%) S. sciuri, 21 (10,3%) S. xylosus, 19 (9,3%) S. epidermidis , 19 (9,3%) S. haemolyticus , 17 (8,3%) S. lentus , 17 (8,3%) S. warneri , 11(5,4%) S. equorum e 5 (2,5%) S. cohnii . Na PCR multiplex, em 14 (6,9%) isolados foi detectada a presença dos genes para enterotoxina E (SEE), em 11 (78,6%) J (SEJ), em 1 (7%) C (SEC) e em 1 (7%) I (SEI). Com base nos resultados, o tipo de embalagem não interferiu na multiplicação dos Staphylococcus spp. isolados dos queijos. Neste estudo, verificou-se que a capacidade para a produção de coagulase pela bactéria não pode ser concebida como indicativa de enterotoxigenicidade, portanto devem-se considerar os CNS como objeto de importância na epidemiologia das intoxicações estafilocócicas, fazendo-se necessária a atenção com relação à pesquisa dos CNS nos alimentos, uma vez que foram detectados genes responsáveis pela produção de toxinas, e nenhuma das amostras apresentou contagem para Staphylococcus spp. acima do limite permitido pela legislação.(AU)

Toxigenic Profiling of Enterotoxin-Producing Bacillus cereus Isolated from Marketed Raw Chicken Meat and Human Subjects by Triplex and Multiplex PCR

Bacillus cereus incorporates the most important group of endospore-forming micro organism and can cause emetic and diarrheal food poisoning. A total of 42 B. cereus strains isolated from marketed raw chicken meat and human subjects swab samples were assessed by a triplex and multiplex PCR for the presence of enterotoxin genes. The detection rate of nheB, hblA, hblD, cytK, nheA,CER, hblC and entFM enterotoxin genes among all B. cereus strains was 83.33%, 80.95%, 69.04%, 21.42%, 47.61%, 0%, 61.90%, and 92.85% respectively. Enterotoxigenic profiles were determined in enterotoxin-producing strains showed 19 different patterns. The results offer essential information on toxin genes prevalence and toxigenic profiles of B. cereus from sources of origin. The present study was taken into consideration about extreme fitness danger for public health and insuring extra ability in difficulty to food safety amongst all B. cereus group members. Also, there may be need for extensive and continuous tracking of food products embracing both emetic toxin and enterotoxin genes.

Enterotoxin-encoding genes in Staphylococcus aureus from buffalo milk / Genes codificadores de enterotoxinas em Staphylococcus aureus no leite de búfalas

This paper investigated the occurrence of Staphylococcus aureus and the detection of enterotoxin-encoding genes of these strains in milk collected from 30 Murrah buffaloes used to produce dairy products in Brazil. A total of 68 strains of Staphylococcus aureus were found as identified by conventional laboratory tests, and thus screened for sea, seb, sec, sed, see, seg, seh and sei enterotoxin-encoding genes by polymerase chain reaction (PCR). Twelve strains containing enterotoxin-amplified genes were found, with higher expression for the sei and seh genes. These results can be attributed to animal health and inadequate cleaning of the equipment, indicating the need for better quality control in animal production and health lines. The results of this study with the presence of pathogens and their enterotoxigenic potential indicate a source of food poisoning, as well as being a pioneering study in the detection of new enterotoxins for buffalo milk.(AU)

Este estudo investigou a ocorrência de isolados de Staphylococcus aureus e a detecção de genes que codificam a enterotoxigenicidade dessas cepas em leite de búfala utilizado na produção de laticínios no Brasil. As amostras foram coletados em 30 búfalos da raça Murrah, identificado por testes laboratoriais convencionais, foram identificados um total de 68 cepas de S. aureus e rastreados para os genes que codificam a enterotoxina sea, seb, sec, sed, see, seg, seh and sei por reação em cadeia da polimerase (PCR). Doze cepas contendo genes da enterotoxina foram amplificadas, com maior expressão para os genes sei e seh. Esses resultados podem ser atribuídos à saúde animal e à higiene inadequada do equipamento, indicando a necessidade de melhor controle de qualidade nas linhas de produção e saúde animal. Os resultados desta pesquisa, com a presença de patógenos e seu potencial enterotoxigênico, indicam uma fonte de intoxicação alimentar, além de ser uma pesquisa pioneira na detecção de novas enterotoxinas para o leite de búfala.(AU)

Staphylococcus aureus resistentes a meticilina (SARM) y productores de enterotoxina A aislados de portadores nasales asintomáticos entre estudiantes universitarios de México / Methicillin resistant Staphylococcus aureus (MRSA) and enterotoxin A producer isolated from asymptomatic nasal carriage among undergraduate students of Mexico

El objetivo de este estudio fue determinar la frecuencia de S. aureus, incluyendo resistentes a meticilina y la producción de enterotoxina A en fosas nasales de estudiantes universitarios en México. Este fue un estudio transversal realizado en 471 estudiantes universitarios de una ciudad del suroeste de México. Las muestras nasales y los datos sociodemográficos fueron obtenidos de los pacientes. Las cepas fueron identificadas como S. aureus basándose en la morfología, tinción de Gram, prueba de catalasa, prueba de coagulasa y fermentación en agar manitol salado. Las cepas se biotipificaron, se determinó la resistencia a meticilina por difusión en agar y la producción de enterotoxina A por Dot- Blot. La frecuencia de portadores nasales de S. aureus fue 10,40 %; 73,46 % resistentes a meticilina; 36,73 % producen enterotoxina A. En un análisis bivariado, se encontraron diferencias estadísticamente significativas en pacientes que viven cerca de aguas residuales y granjas con el estado de portador de S. aureus, (p=0,01, OR 2,59 [1,06-5,81]; p=0,01, OR 3,18, [1,07- 8,33]). Los portadores nasales muestran una diversidad de cepas de S. aureus, mayormente resistentes a meticilina, pero no todas producen enterotoxina A.

The aim at this study was determine the frequency of S. aureus, including methicillin-resistant and enterotoxin A production in nostrils of university students in Mexico. This was a cross-sectional study conducted in 471 university students from a city in southwestern Mexico. Nasal samples and sociodemographic data were obtained from the patients. Strains were identified as S. aureus based on morphology, Gram stain, catalase test, coagulase test and fermentation on salted mannitol agar. Isolated strains were subjected to biotyping, their methicillin resistance was analyzed using the agar diffusion method and examined their enterotoxin A (SEA) production by a Dot-blot analysis. The nasal carriage rate of S. aureus was 10.40%; 73.46% of the isolates were resistant to methicillin; 36.73% of the strains produced enterotoxin A. In the bivariate analysis, a statistically significant difference was found in patients who lived near sewage and farms with S. aureus carriage (p=0.012, odds ratio 2.59, [ 1.06-5.81]; p=0.009, odds ratio 3.18, [1.07- 8.33]) and the first group also associated with methicillin resistant S. aureus carriage (p=0.020, odds ratio 3.38, [1.30-8.06]). Nasal carriers show a wide variety of strains of S. aureus, mostly MRSA strains, but not all produce enterotoxin A.

Advances in the application of claudins to tumor therapy / 生物工程学报

Claudin proteins are the most crucial components of tight junctions, and play an essential role in maintaining cell polarity, regulating cell permeability and the intercellular ion. In recent years, many studies have shown that abnormality of claudins expression is implicated in the tumor progression. The expression correlates with tumor prognosis and can serve as a biomarker of prognosis and potential therapeutic targets. This review summarizes the current knowledge regarding claudin dysregulation in cancer and highlights the progress in claudin-based treatments.

Characteristic profiles of biofilm, enterotoxins and virulence of Staphylococcus aureus isolates from dairy cows in Xinjiang Province, China

As an important zoonotic pathogen, Staphylococcus aureus has led to serious mastitis and endometritis in infected dairy cows. In this study, a total of 164 strains of S. aureus were isolated from dairy cows in Xinjiang Province, China, and subjected to assays to determine drug susceptibility and biofilm (BF) formation ability. Enterotoxin-related genes were detected, and the transcription levels of genes related to BF formation were determined by using reverse transcription-quantitative polymerase chain reaction. Moreover, the pathogenicity of isolates with different BF formation abilities was determined by measuring their hemolysis activity, half lethal dose (LD₅₀) and organ bacterial load. The results showed that 86.0% of S. aureus isolates could form BF. Among them, 42.1% of the strains had weak BF formation ability, and most strains with a strong BF formation ability were ica gene carriers. The S. aureus isolates displayed multidrug resistance and their drug resistance was positively correlated with their BF formation ability. Moreover, 96.3% of the S. aureus isolates carried enterotoxin genes. Among them, the detection rates of the novel enterotoxin genes were higher than those of conventional enterotoxin genes. Furthermore, isolates with a strong BF formation ability had higher LD50 but lower hemolysis ability and organ bacterial load than those of the isolates with weak or no BF ability. However, isolates without BF ability produced more severe pathological changes than those of isolates with strong BF formation ability. These findings suggest that higher BF ability and presence of novel enterotoxin genes are important characteristics of S. aureus isolates from dairy cows in Xinjiang Province, China, and such isolates may pose potential threats to food safety.

Frequency of Staphylococcus aureus virulence genes in milk of cows and goats with mastitis / Frequência de genes fatores de virulência de Staphylococcus aureus em leite de vacas e cabras com mastite

The present study determined the frequency of Staphylococcus aureus virulence genes in 2,253 milk samples of cows (n=1000) and goats (n=1253) raised in three different geographical regions of the state Pernambuco, Brazil. The presence of genes of virulence factors associated to adhesion to host cells (fnbA, fnbB, clfA and clfB), toxinosis (sea, seb, sec, sed, seg, seh, sei, tsst, hla and hlb), and capsular polysaccharide (cap5 and cap8) was evaluated by PCR. A total of 123 and 27 S. aureus strains were isolated from cows' and goats' milk, respectively. The sec and tsst genes were detected exclusively in goats' isolates, while the seh gene was only identified in cows' isolates. The number of toxin genes per strain showed that goats' isolates are likely more toxic than bovines' isolates. The cap5 genotype predominated in both host species, especially in strains collected from cows raised in the Agreste region. The cap8 genotype is likely more virulent due to the number of virulence genes per strain. The results of the present study demonstrate that S. aureus may pose a potential threat to human health in Brazil, and, therefore, these results should support actions related to mastitis control programs.(AU)

O presente estudo determinou a frequência de genes de virulência de Staphylococcus aureus em 2253 amostras de leite, sendo de vacas n=1000 e de cabras n=1253, procedentes das três regiões geográficas do estado de Pernambuco, Brasil. A presença de genes de fatores de virulência associados à adesão às células hospedeiras (fnbA, fnbB, clfA e clfB), toxinosis (sea, seb, sec, sed, seg, seh, sei, tsst, hla e hlb) e polissacarídeo capsular (cap5 e cap8) foram avaliadas por PCR. Um total de 123 e 27 cepas de S. aureus foram isoladas do leite de vacas e cabras, respectivamente. Os genes sec e tsst foram detectados exclusivamente em isolados de cabras, enquanto o gene seh foi identificado apenas em isolados de vaca. O número de genes de toxina por cepa mostrou que os isolados de cabras são potencialmente mais tóxicos do que os isolados obtidos de bovinos. O genótipo cap5 predominou em ambas as espécies hospedeiras, especialmente em cepas coletadas de vacas criadas na região Agreste. O genótipo cap8 é potencialmente mais virulento devido ao número de genes de virulência por isolado. Os resultados do presente estudo demonstram que S. aureus pode representar uma ameaça potencial para a saúde humana no Brasil e, portanto, estes resultados devem subsidiar ações relacionadas aos programas de controle de mastite.(AU)

Correlation analysis of drug resistance of Salmonella and enterotoxin genes in 132 children with diarrhea in Taizhou area / 中国基层医药

Objective To investigate the drug resistance of Salmonella and enterotoxin gene in diarrhea children of Taizhou.Methods 132 children with Salmonella infection who had fever ,diarrhea and other symptoms and were confirmed by fecal culture were selected .The Salmonella serotype , drug resistance analysis of 10 kinds of antibiotics,and enterotoxin gene (spvA,spvB,rck) were detected.Results 132 cases of Salmonella isolated from blood serological were identified a total of 10 serotypes,Salmonella typhimurium and Salmonella Enteritidis were the most common.In 132 strains of Salmonella ,the highest drug resistance rate was to ampicillin (51.82％) and ampicil-lin/sulbactam(51.52％),and had no resistance to imipenem ,ertapenem.In 132 strains of Salmonella,including sin-gle drug resistance of 27 strains(20.45％),the rest had two or more drugs resistance .In 132 strains of Salmonella, 132 strains were spvA positive(positive rate 100％),38 cases were spvB positive(positive rate 28.79％),45 cases were rck positive(positive rate 34.09％).The incidence rates of fever,dehydration and hematochezia in spvB positive children were significantly higher than those in spvB negative children (χ2 =6.022,6.661,6.978,all P<0.05).The incidence rates of fever and hematochezia in rck positive children were significantly higher than those in rck negative children (χ2 =9.134,12.673,all P<0.05).Conclusion Salmonella infection diarrhea children in the Taizhou area are mainly Salmonella typhimurium and Salmonella enteritidis infection ,the strains are highly resistant strains , enterotoxin spvB gene is correlated with the incidence rates of fever ,dehydration and hematochezia ,and rck gene is correlated with the incidence rates of fever and hematochezia .

Frequência de genes codificadores de toxinas em Staphylococcus aureus isolados de leite de tanques expansão comunitários / Frequency of toxin-encoding genes in Staphylococcus aureus isolated from community milk tanks

A capacidade de produção de toxinas pelo Staphylococcus aureus no leite e produtos derivados está relacionado com surtos de intoxicação alimentar. Objetivou-se nesta pesquisa, estudar a ocorrência de genes que codificam para enterotoxinas estafilocócicas (sea, seb, sed, seg, seh e sei) e toxinas α e ß hemolítica (hla e hlb) em S. aureus isolados de 53 amostras de leite de tanques expansão comunitários no Estado de Alagoas, Brasil. Foram identificados 27 isolados (50,94%) como S. aureus pela amplificação do gene nuc. 13/27 isolados (48,1%) foram positivos para pelo menos um gene das enterotoxinas estudadas, sendo as frequências dos genes sea 33,3%, seh 18,5%, sei 11,1% e sed 7,4%; não entanto não foram identificados os genes seb e seg nestas bactérias. Para as toxinas hemolíticas, 51,9% dos isolados portavam ambos genes (hla e hlb), sendo a frequência para o gene hla de 81,5% e para o gene hlb de 51,9%. A frequência de genes das toxinas avaliadas é alta o que constitui um risco potencial para a saúde pública em especial, as enterotoxinas por serem termoestáveis e estarem asssociados com surtos de intoxicação alimentar.(AU)

The capacity of toxin production by Staphylococcus aureus in milk and dairy products is associated with food poisoning outbreaks. The objective of this research was to study the frequency of genes encoding staphylococcal enterotoxin (sea, seb, sed, seg, seh and sei) and α and ß hemolytic toxins (hla and hlb) in S. aureus isolates from 53 milk samples from community tanks in the State of Alagoas, Brazil. Twenty-seven isolates (50.94%) were identified as S. aureus by nuc gene amplification; 13/27 isolates (48.1%) were positive for at least one gene of the studied enterotoxins and the frequency of genes sea was 33.3%, seh 18.5%, sei 11.1% and sed 7.4%; the seb and sec genes have not been identified in the bacteria. For the hemolytic toxins, 51.9% of isolates harbored both genes (hla and hlb), the frequency of hla gene was 81.5% and 51.9% for the hlb gene. The evaluated toxin-encoding gene frequency is high and constitutes a potential risk for public health, especially staphylococcal enterotoxin genes; because they are heat-stable enterotoxins and have been associated with food poisoning.(AU)

Establishment of a mouse model of IgA nephropathy induced by superantigen staphylococcal enterotoxin B / 中国比较医学杂志

Objective To establish a mouse model of IgA nephropathy and to observe its biochemical and pathological characteristics. Methods Twelve BALB/c mice were randomly divided into the normal group and model group, with 6 mice in each group. Mice in the model group received an intravenous injection of 0. 8 mg/kg superantigen staphylococcal enterotoxin B (SEB) into the tail vein once a week for three weeks. At the end of the 4th week, the mice were sacrificed, and the 24 h-urinary protein, urinary microalbumin, the renal function indicators BUN, Scr and UA were measured, levels of liver function indicators ALT, AST, ALP, and the blood lipid levels of TC, TG, and LDL were determined, the renal morphological changes were examined by pathology using HE, PAS, PASM and Masson staining, and by electron microscopy, the IgA deposition in the renal tissue was observed with immunofluorescence, and the liver and small intestine were observed by pathology using HE staining. Results Compared with the normal group, the mice of model group showed increased 24-hour urinary protein and urinary microalbumin (P<0. 01), increased CREA and UA (P<0. 05), but not significantly changed BUN, TP and ALB. The liver function indicator AST was significantly increased (P<0. 05), but ALT and ALP were not significantly changed. The blood lipid TG was significantly decreased (P<0. 05) and LDL increased (P<0. 01), while the TC was not significantly changed. The kidney tissues had moderate histological changes, and immunofluorescence observation showed granular or massive IgA deposition in the renal glomerular mesangium. The liver tissue had some inflammatory cell infiltration and hepatocyte necrosis. The small intestine showed slender and shortened villi with widened inter-villous space and sloughed off epithelial cells, dilated central lacteal, and lymphocyte infiltration. Conclusions A mouse model of IgA nephropathy can be successfully established by tail vein injection of superantigen staphylococcal entrotoxin B.

Effects of storage temperatures on survival and enterotoxin production of Staphylococcus aureus in Turkish white pickled cheese

Aims: Turkish white pickled cheese is the most consumed cheese type in Turkey and it is an important food to be evaluated in terms of food safety. In this study we investigated the behavior (survival and production of enterotoxin) of Staphylococcus aureus (S. aureus) NCTC 10654 in Turkish white pickled cheeses, which were ripened at 4 °C and 12 °C for 90 days. Methodology and results: Counting of microorganisms was carried out by conventional methods on appropriate media. Detection of enterotoxins was performed by double-sandwich ELISA technique and gene region responsible for enterotoxin production by reverse transcription-PCR (RT-PCR). The counts of S. aureus decreased (p 0.05). Staphylococcal enterotoxin could not be detected in the cheeses during ripening. Staphylococcal enterotoxin (SE) B mRNA was detected in cheese samples on days 1, 15, and 30 of ripening by RT-PCR. The SEB mRNA expression levels had differed according to the storage temperature. Conclusion, significance and impact of study: This study showed that enterotoxin B producing S. aureus decreased in Turkish white pickled cheese stored at different temperatures and it could not produce enterotoxins, possibly due to factors such as type and nature of the cheese, and the conditions of production and activity of the starter culture.

Field epidemiological investigation on a foodborne outbreak caused by Staphylococcus aureus enterotoxin, in Hangzhou, 2014 / 中华流行病学杂志

Objective To identify the cause on a foodbome breakout in a university of Hangzhou in 2014.Methods Data on cases were gathered from the out-patient logs of the university affiliated or neighboring hospitals to describe the disease distribution and epidemiological curves.Case-control and field studies on hazard factors were conducted simultaneously.Results The incubation period was 1.5-5.0 hours,of which the median was 3 during the outbreak.All the cases consumed food from a restaurant called Chen's Snacks nearby their university and suffered from the Staphylococcus aureus enterotoxin.Results from the Staphylococcus enterotoxin testing were positive in 3 stool and 6 food samples,out of the total 18 samples.Conclusion This foodborne outbreak was caused through food poisoning by vermicelli which was contaminated with Staphylococcus aureus.

Field epidemiological investigation on a foodborne outbreak caused by Staphylococcus aureus enterotoxin, in Hangzhou, 2014 / 中华流行病学杂志

Objective To identify the cause on a foodbome breakout in a university of Hangzhou in 2014.Methods Data on cases were gathered from the out-patient logs of the university affiliated or neighboring hospitals to describe the disease distribution and epidemiological curves.Case-control and field studies on hazard factors were conducted simultaneously.Results The incubation period was 1.5-5.0 hours,of which the median was 3 during the outbreak.All the cases consumed food from a restaurant called Chen's Snacks nearby their university and suffered from the Staphylococcus aureus enterotoxin.Results from the Staphylococcus enterotoxin testing were positive in 3 stool and 6 food samples,out of the total 18 samples.Conclusion This foodborne outbreak was caused through food poisoning by vermicelli which was contaminated with Staphylococcus aureus.

Plesiomonas shigelloides exports a lethal cytotoxic-enterotoxin (LCE) by membrane vesicles

ABSTRACT Plesiomonas shigelloides isolated from water in Brazil was previously described as a hemorrhagic heat-labile cytotoxic-enterotoxin producer. We purified this toxin from culture supernatants using ion metallic affinity chromatography (IMAC) followed by molecular exclusion chromatography. The pure toxin presented molecular mass of 50 kDa and isoelectric point (pI) around 6.9 by 2D electrophoresis. When injected intravenously, the purified cytotoxic-enterotoxin induced also severe spasms followed by sudden death of mice. Hence, we entitled it as lethal cytotoxic-enterotoxin (LCE). The presence of membrane vesicles (MVs) on cell surfaces of P. shigelloides was observed by scan electron microscopy (SEM). From these MVs the LCE toxin was extracted and confirmed by biological and serological assays. These data suggest that P. shigelloides also exports this cytotoxic-enterotoxin by membrane vesicles, a different mechanism of delivering extra cellular virulence factors, so far not described in this bacterium.

Construction and identification of lentiviral vector over-expressing Staphyloco-ccus aureus enterotoxin C3 / 中国免疫学杂志

Objective:To construct the lentiviral vector over-expressing Staphylococcus aureus enterotoxin C3 and detect the expression of target gene in vitro.Methods:SEC3 gene were amplificatied by polymerase chain rcaction( PCR).The GV365 lentiviral vectors were digested by AgeⅠenzyme,which was linked to SEC3 gene and then constructed the GV365-SEC3 lentiviral vetor.Positive clones of vectors were identificd by PCR.Then the positive lentiviral vectors were transfected into 293T cells for lentivirus package.The expression of lentiviral vectors was tested by observating cell fluorescence and Western blot.The virus titer was determined by HIV-1 p24 ELISA.Results: SEC3 gene was amplified and successfully bound to the GV365 lentivirus vectors.The sequences of the recombinant plasmid were confirmed correct by PCR and DNA scqucncing.A large mass of green fluorescent cells were observed after transfecting.And the resulting size of 29 kD protein band of protein electrophoresis, which was consistent with the target gene protein.Viral vector titer was 5×108 TU/ml by ELISA detection.Conclusion: Lentiviral vector over-expressing Staphylococcus aureus enterotoxin C3 was successfully constructed,laid the foundation of observing its effect and mechanism against to tumor in vivo and in vitro for later research.