How microbiological tests reflect bacterial pathogenesis and host adaptation.

Historically, clinical microbiological laboratories have often relied on isolation of pure cultures and phenotypic testing to identify microorganisms. These clinical tests are often based on specific biochemical reactions, growth characteristics, colony morphology, and other physiological aspects. The features used for identification in clinical laboratories are highly conserved and specific for a given group of microbes. We speculate that these features might be the result of evolutionary selection and thus may reflect aspects of the life cycle of the organism and pathogenesis. Indeed, several of the metabolic pathways targeted by diagnostic tests in some cases may represent mechanisms for host colonization or pathogenesis. Examples include, but are not restricted to, Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae, Salmonella enterica, Shigella spp., and enteroinvasive Escherichia coli (EIEC). Here, we provide an overview of how some common tests reflect molecular mechanisms of bacterial pathogenesis.

Epidemiology of Shigella infections and diarrhea in the first two years of life using culture-independent diagnostics in 8 low-resource settings.

Culture-independent diagnostics have revealed a larger burden of Shigella among children in low-resource settings than previously recognized. We further characterized the epidemiology of Shigella in the first two years of life in a multisite birth cohort. We tested 41,405 diarrheal and monthly non-diarrheal stools from 1,715 children for Shigella by quantitative PCR. To assess risk factors, clinical factors related to age and culture positivity, and associations with inflammatory biomarkers, we used log-binomial regression with generalized estimating equations. The prevalence of Shigella varied from 4.9%-17.8% in non-diarrheal stools across sites, and the incidence of Shigella-attributable diarrhea was 31.8 cases (95% CI: 29.6, 34.2) per 100 child-years. The sensitivity of culture compared to qPCR was 6.6% and increased to 27.8% in Shigella-attributable dysentery. Shigella diarrhea episodes were more likely to be severe and less likely to be culture positive in younger children. Older age (RR: 1.75, 95% CI: 1.70, 1.81 per 6-month increase in age), unimproved sanitation (RR: 1.15, 95% CI: 1.03, 1.29), low maternal education (<10 years, RR: 1.14, 95% CI: 1.03, 1.26), initiating complementary foods before 3 months (RR: 1.10, 95% CI: 1.01, 1.20), and malnutrition (RR: 0.91, 95% CI: 0.88, 0.95 per unit increase in weight-for-age z-score) were risk factors for Shigella. There was a linear dose-response between Shigella quantity and myeloperoxidase concentrations. The burden of Shigella varied widely across sites, but uniformly increased through the second year of life and was associated with intestinal inflammation. Culture missed most clinically relevant cases of severe diarrhea and dysentery.

Acute diarrhea with blood: diagnosis and drug treatment / Diarreia aguda com sangue: diagnóstico e tratamento medicamentoso

Abstract Objective To restate the epidemiological importance of Shigella in acute diarrhea with blood, providing an overview of the treatment and stressing the need for the correct indication of antibiotic therapy. Sources of Data A search was carried out in the Medline and Scopus databases, in addition to the World Health Organization scientific documents and guidelines, identifying review articles and original articles considered relevant to substantiate the narrative review. Synthesis of Data Different pathogens have been associated with acute diarrhea with blood; Shigella was the most frequently identified. The manifestations of shigellosis in healthy individuals are usually of moderate intensity and disappear within a few days. There may be progression to overt dysentery with blood and mucus, lower abdominal pain, and tenesmus. Conventional bacterial stool culture is the gold standard for the etiological diagnosis; however, new molecular tests have been developed to allow the physician to initiate targeted antibacterial treatment, addressing a major current concern caused by the increasing resistance of Shigella. Prevention strategies include breastfeeding, hygiene measures, health education, water treatment, and the potential use of vaccines. Conclusions Acute diarrhea is an important cause of mortality in children under 5 years and shigellosis is the leading cause of acute diarrhea with blood worldwide. The current concern is the increase in microbial resistance to the recommended antibiotics, which brings an additional difficulty to therapeutic management. Although no vaccine is yet available against Shigella, several candidates are undergoing clinical trials, and this may be the most cost-effective preventative measure in future.

Resumo Objetivo Reiterar a importância epidemiológica da Shigella na diarreia aguda com sangue, fornecer uma visão geral do tratamento e ressaltar a necessidade da correta indicação da antibioticoterapia. Fontes dos dados Realizada pesquisa nos bancos de dados Medline e Scopus, além de documentos científicos e diretrizes da Organização Mundial da Saúde, com a identificação de artigos de revisão e artigos originais considerados relevantes para fundamentar a revisão do tipo narrativa. Síntese dos dados Diferentes patógenos têm sido associados à diarreia aguda com sangue, a Shigella é o mais frequente. As manifestações da shigelose em indivíduos saudáveis são geralmente de intensidade moderada e desaparecem em poucos dias. Pode haver progressão para disenteria franca com sangue e muco, dor em abdome inferior e tenesmo. A coprocultura bacteriana convencional é o padrão-ouro para o diagnóstico etiológico, porém novos testes moleculares foram desenvolvidos, os quais permitem ao médico iniciar tratamento antibacteriano direcionado, sanar uma grande preocupação atual, devido à crescente resistência da Shigella. Estratégias de prevenção incluem aleitamento, medidas de higiene, educação em saúde, tratamento da água e o potencial uso de vacinas. Conclusões A diarreia aguda é uma importante causa de mortalidade em crianças com menos de cinco anos e a shigelose é a principal causa de diarreia aguda com sangue em todo o mundo. A preocupação atual é o aumento da resistência microbiana aos antibióticos preconizados, o que traz uma dificuldade adicional ao manejo terapêutico. Embora ainda não exista vacina disponível para Shigella, várias candidatas estão em fase de testes clínicos, podem futuramente ser a medida preventiva mais custo-efetiva.

Acute diarrhea with blood: diagnosis and drug treatment.

OBJECTIVE: To restate the epidemiological importance of Shigella in acute diarrhea with blood, providing an overview of the treatment and stressing the need for the correct indication of antibiotic therapy. SOURCES OF DATA: A search was carried out in the Medline and Scopus databases, in addition to the World Health Organization scientific documents and guidelines, identifying review articles and original articles considered relevant to substantiate the narrative review. SYNTHESIS OF DATA: Different pathogens have been associated with acute diarrhea with blood; Shigella was the most frequently identified. The manifestations of shigellosis in healthy individuals are usually of moderate intensity and disappear within a few days. There may be progression to overt dysentery with blood and mucus, lower abdominal pain, and tenesmus. Conventional bacterial stool culture is the gold standard for the etiological diagnosis; however, new molecular tests have been developed to allow the physician to initiate targeted antibacterial treatment, addressing a major current concern caused by the increasing resistance of Shigella. Prevention strategies include breastfeeding, hygiene measures, health education, water treatment, and the potential use of vaccines. CONCLUSIONS: Acute diarrhea is an important cause of mortality in children under 5 years and shigellosis is the leading cause of acute diarrhea with blood worldwide. The current concern is the increase in microbial resistance to the recommended antibiotics, which brings an additional difficulty to therapeutic management. Although no vaccine is yet available against Shigella, several candidates are undergoing clinical trials, and this may be the most cost-effective preventative measure in future.

[Shigella flexneri bacteremia in children: two case report and review of literature]. / Bacteriemia por Shigella flexneri en dos lactantes.

Shigella spp. is the most frequent micro-biological isolation in bacterial diarrhea in Argentina. It causes a watery diarrhea or dysenteric disease. It rarely causes extraintestinal problems. It has an incidence of bacteremia of 0,4-7,3%, and its appearance compels us to look for associated risk factors, as children under one year of age and immunodeficiency, among others. We describe two children with Shigella flexneri bacteremia. They presented with fever and diarrhea. One of them had primary immune deficiency.

Enterobacterial repetitive intergenic consensus (ERIC)-PCR analysis as a reliable evidence for suspected Shigella spp. outbreaks

Background: Shigellosis remains a serious public health problem and an important cause of morbidity and mortality worldwide. The aim of this study was to characterize fliC and the genetic relatedness of Shigella spp. isolated during a one-year period from children in a suspected outbreak in Tehran, Iran. Methods and results: Fifty Shigella spp. were isolated from 3779 stool samples of children with diarrhea (prevalence rate: 1.32%). Among the isolates, 92% were characterized as Shigella sonnei, while 6% and 2% were identified as S. flexneri and S. boydii, respectively. S. dysenteriae was not recovered from the patients. All isolates were negative for fliC except for Shigella standard strains. The enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR) profiles allowed differentiating the 50 isolates into 5 ERIC types, which were grouped into five clusters (ET1-ET5). Computer-assisted clustering of the strains showed a high degree of similarity among the isolates. Conclusion: In conclusion, given the clonal correlation of the Shigella strains isolated in this study and the lack of fliC among them, we propose that probably a single or limited fliC-defected Shigella clone spread and caused the outbreak.(AU)

The other Campylobacters: Not innocent bystanders in endemic diarrhea and dysentery in children in low-income settings.

BACKGROUND: Campylobacter is one of the main causes of gastroenteritis worldwide. Most of the current knowledge about the epidemiology of this food-borne infection concerns two species, C. coli and C. jejuni. Recent studies conducted in developing countries and using novel diagnostic techniques have generated evidence of the increasing burden and importance of other Campylobacter species, i.e. non-C. coli/jejuni. We performed a nested case-control study to compare the prevalence of C. coli/jejuni and other Campylobacter in children with clinical dysentery and severe diarrhea as well as without diarrhea to better understand the clinical importance of infections with Campylobacter species other than C. coli/jejuni. METHODOLOGY/PRINCIPAL FINDINGS: Our nested case-control study of 439 stool samples included dysenteric stools, stools collected during severe diarrhea episodes, and asymptomatic stools which were systematically selected to be representative of clinical phenotypes from 9,160 stools collected during a birth cohort study of 201 children followed until two years of age. Other Campylobacter accounted for 76.4% of the 216 Campylobacter detections by qPCR and were more prevalent than C. coli/jejuni across all clinical groups. Other Campylobacter were also more prevalent than C. coli/jejuni across all age groups, with older children bearing a higher burden of other Campylobacter. Biomarkers of intestinal inflammation and injury (methylene blue, fecal occult test, myeloperoxidase or MPO) showed a strong association with dysentery, but mixed results with infection. MPO levels were generally higher among children infected with C. coli/jejuni, but Shigella-infected children suffering from dysentery recorded the highest levels (26,224 ng/mL); the lowest levels (10,625 ng/mL) were among asymptomatic children infected with other Campylobacter. Adjusting for age, sex, and Shigella infection, dysentery was significantly associated with C. coli/jejuni but not with other Campylobacter, whereas severe diarrhea was significantly associated with both C. coli/jejuni and other Campylobacter. Compared to asymptomatic children, children suffering from dysentery had a 14.6 odds of C. coli/jejuni infection (p-value < 0.001, 95% CI 5.5-38.7) but were equally likely to have other Campylobacter infections-odds ratio of 1.3 (0.434, 0.7-2.4). Children suffering from severe diarrhea were more likely than asymptomatic children to test positive for both C. coli/jejuni and other Campylobacter-OR of 2.8 (0.034, 1.1-7.1) and 1.9 (0.018, 1.1-3.1), respectively. Compared to the Campylobacter-free group, the odds of all diarrhea given C. coli/jejuni infection and other Campylobacter infection were 8.8 (<0.001, 3.0-25.7) and 2.4 (0.002, 1.4-4.2), respectively. Eliminating other Campylobacter in this population would eliminate 24.9% of the diarrhea cases, which is almost twice the population attributable fraction of 15.1% due to C. coli/jejuni. CONCLUSIONS/SIGNIFICANCE: Eighty-seven percent of the dysentery and 59.5% of the severe diarrhea samples were positive for Campylobacter, Shigella, or both, emphasizing the importance of targeting these pathogens to limit the impact of dysentery and severe diarrhea in children. Notably, the higher prevalence of other Campylobacter compared to C. coli/jejuni, their increasing burden during early childhood, and their association with severe diarrhea highlight the importance of these non-C. coli/jejuni Campylobacter species and suggest a need to clarify their importance in the etiology of clinical disease across different epidemiological contexts.

Bacteriemia por Shigella flexneri en dos lactantes / Shigella flexneri bacteremia in children: two case report and review of literature

Resumen Shigella spp. es el aislamiento microbiológico más frecuente en las diarreas bacterianas en Argentina. Clínicamente puede causar desde una diarrea acuosa hasta disentería. En forma infrecuente causa complicaciones extraintestinales, con una incidencia de bacteriemia desde 0,4 a 7,3%; asociado a factores de riesgo como niños menores de un año de edad e inmunodeficiencias, entre otros. Presentamos los casos clínicos de dos lactantes con bacteriemia por Shigella flexneri, que consultaron por fiebre y diarrea, uno de ellos con diagnóstico de inmunodeficiencia primaria.

Shigella spp. is the most frequent micro-biological isolation in bacterial diarrhea in Argentina. It causes a watery diarrhea or dysenteric disease. It rarely causes extraintestinal problems. It has an incidence of bacteremia of 0,4-7,3%, and its appearance compels us to look for associated risk factors, as children under one year of age and immunodeficiency, among others. We describe two children with Shigella flexneri bacteremia. They presented with fever and diarrhea. One of them had primary immune deficiency.

Shigella sp: um problema de saúde pública / Shigella sp: a public health problem

O aumento do consumo de refeições fora de casa está associado ao aumento das Doenças Veiculadas por Alimentos (DVA), que são provenientes do consumo de alimentos e água contaminados, principalmente, devido à falta de higiene no preparo dos alimentos e à ausência, em muitos casos, do tratamento da água usada no preparo destes alimentos. A shigelose é uma DVA que se caracteriza como uma doença inflamatória do trato gastrointestinal causada pela Shigella cujos sintomas e características se assemelham à salmonelose. O gênero Shigella possui quatro espécies: S. dysenteriae, S. flexneri, S. boydii e S. sonnei. Para a realização deste trabalho foi realizado levantamento de artigos publicados em revistas científicas sobre o tema, com o objetivo de verificar a incidência de Shigella em alimentos abordando suas características e danos provocados à saúde.(AU)

Brote de shigelosis en la ciudad de Luján, Argentina / Shigelosis outbreak in the city of Lujan, Argentina

El objetivo del estudio fue describir un brote por Shigella sonnei ocurrido en julio de 2012 en Luján, Buenos Aires, Argentina. Estuvieron afectadas 5 personas que asistieron a una reunión familiar, donde consumieron una rosca vienesa de elaboración artesanal adquirida en un comercio. Todos presentaron fiebre, dolores articulares, escalofríos y diarrea no sanguinolenta con mucus. Se realizaron coprocultivos en los afectados y análisis microbiológicos de los ingredientes. Se aisló y caracterizó S.sonnei de todos los pacientes y de la crema de almendras empleada en la preparación de la rosca vienesa. A los aislamientos se les determinó el perfil de sensibilidad a los antimicrobianos y el genético por electroforesis en campo pulsado. Los resultados demostraron la relación genética de los aislamientos, y esto confirmó la ocurrencia de los casos por exposición a una misma fuente de infección, la crema de almendras. Al ser un ingrediente industrial, de improbable contaminación inicial, la crema de almendras podría haber sufrido una contaminación durante la manipulación en la panadería

The aim of this study was to describe an outbreak of Shigella sonnei that occurred in the city of Lujan, Buenos Aires, Argentina, in July 2012. Five individuals were affected after eating a handmade Viennese-style pastry at a family gathering. All of them presented with fever, joint pain, chills and non-bloody diarrhea containing mucus. Stool cultures were performed in all cases and the samples taken from the pastry ingredients were analyzed microbiologically. S.sonnei was isolated and identified in all the patients involved as well as in the almond cream filling. The isolates were analyzed for determining the antimicrobial susceptibility and genetic profiles by pulsed field gel electrophoresis (PFGE). The results showed the genetic relationship among the isolates, confirming that the cases occurred due to the patients' exposure to the same source of infection, i.e., the almond cream. Being the almond cream an industrially-manufactured ingredient, an initial contamination could have been unlikely; however contamination might have occurred as a result of manipulation in the bakery

Update on molecular epidemiology of Shigella infection.

PURPOSE OF REVIEW: Shigella spp. are important etiologic agents of diarrhea worldwide. This review summarizes the recent findings on the epidemiology, diagnosis, virulence genes, and pathobiology of Shigella infection. RECENT FINDINGS: Shigella flexneri and Shigella sonnei have been identified as the main serogroups circulating in developing and developed countries, respectively. However, a shift in the dominant species from S. flexneri to S. sonnei has been observed in countries that have experienced recent improvements in socioeconomic conditions. Despite the increasing usage of molecular methods in the diagnosis and virulence characterization of Shigella strains, researchers have been unsuccessful in finding a specific target gene for this bacillus. New research has demonstrated the role of proteins whose expressions are temperature-regulated, as well as genes involved in the processes of adhesion, invasion, dissemination, and inflammation, aiding in the clarification of the complex pathobiology of shigellosis. SUMMARY: Knowledge about the epidemiologic profile of circulating serogroups of Shigella and an understanding of its pathobiology as well as of the virulence genes is important for the development of preventive measures and interventions to reduce the worldwide spread of shigellosis.

Relationship among Shigella spp. and enteroinvasive Escherichia coli (EIEC) and their differentiation

Shigellosis produces inflammatory reactions and ulceration on the intestinal epithelium followed by bloody or mucoid diarrhea. It is caused by enteroinvasive E. coli (EIEC) as well as any species of the genus Shigella, namely, S. dysenteriae, S. flexneri, S. boydii, and S. sonnei. This current species designation of Shigella does not specify genetic similarity. Shigella spp. could be easily differentiated from E. coli, but difficulties observed for the EIEC-Shigella differentiation as both show similar biochemical traits and can cause dysentery using the same mode of invasion. Sequencing of multiple housekeeping genes indicates that Shigella has derived on several different occasions via acquisition of the transferable forms of ancestral virulence plasmids within commensal E. coli and form a Shigella-EIEC pathovar. EIEC showed lower expression of virulence genes compared to Shigella, hence EIEC produce less severe disease than Shigella spp. Conventional microbiological techniques often lead to confusing results concerning the discrimination between EIEC and Shigella spp. The lactose permease gene (lacY) is present in all E. coli strains but absent in Shigella spp., whereas β-glucuronidase gene (uidA) is present in both E. coli and Shigella spp. Thus uidA gene and lacY gene based duplex real-time PCR assay could be used for easy identification and differentiation of Shigella spp. from E. coli and in particular EIEC.

Relationship among Shigella spp. and enteroinvasive Escherichia coli (EIEC) and their differentiation

Shigellosis produces inflammatory reactions and ulceration on the intestinal epithelium followed by bloody or mucoid diarrhea. It is caused by enteroinvasive E. coli (EIEC) as well as any species of the genus Shigella, namely, S. dysenteriae, S. flexneri, S. boydii, and S. sonnei. This current species designation of Shigella does not specify genetic similarity. Shigella spp. could be easily differentiated from E. coli, but difficulties observed for the EIEC-Shigella differentiation as both show similar biochemical traits and can cause dysentery using the same mode of invasion. Sequencing of multiple housekeeping genes indicates that Shigella has derived on several different occasions via acquisition of the transferable forms of ancestral virulence plasmids within commensal E. coli and form a Shigella-EIEC pathovar. EIEC showed lower expression of virulence genes compared to Shigella, hence EIEC produce less severe disease than Shigella spp. Conventional microbiological techniques often lead to confusing results concerning the discrimination between EIEC and Shigella spp. The lactose permease gene (lacY) is present in all E. coli strains but absent in Shigella spp., whereas β-glucuronidase gene (uidA) is present in both E. coli and Shigella spp. Thus uidA gene and lacY gene based duplex real-time PCR assay could be used for easy identification and differentiation of Shigella spp. from E. coli and in particular EIEC.

Relationship among Shigella spp. and enteroinvasive Escherichia coli (EIEC) and their differentiation.

Shigellosis produces inflammatory reactions and ulceration on the intestinal epithelium followed by bloody or mucoid diarrhea. It is caused by enteroinvasive E. coli (EIEC) as well as any species of the genus Shigella, namely, S. dysenteriae, S. flexneri, S. boydii, and S. sonnei. This current species designation of Shigella does not specify genetic similarity. Shigella spp. could be easily differentiated from E. coli, but difficulties observed for the EIEC-Shigella differentiation as both show similar biochemical traits and can cause dysentery using the same mode of invasion. Sequencing of multiple housekeeping genes indicates that Shigella has derived on several different occasions via acquisition of the transferable forms of ancestral virulence plasmids within commensal E. coli and form a Shigella-EIEC pathovar. EIEC showed lower expression of virulence genes compared to Shigella, hence EIEC produce less severe disease than Shigella spp. Conventional microbiological techniques often lead to confusing results concerning the discrimination between EIEC and Shigella spp. The lactose permease gene (lacY) is present in all E. coli strains but absent in Shigella spp., whereas ß-glucuronidase gene (uidA) is present in both E. coli and Shigella spp. Thus uidA gene and lacY gene based duplex real-time PCR assay could be used for easy identification and differentiation of Shigella spp. from E. coli and in particular EIEC.

[Bacteraemia due to Shigella flexneri serotype 6 in two patients with AIDS]. / Bacteriemia por Shigellaflexneri serotipo 6 en pacientes con SIDA: Presentación de dos casos clínicos.

Infections due to Shigella usually remain localized to the digestive tract and are self-limited. Bacteremia is a potentially lethal complication that can occur in immunocompromised patients. We describe two episodes of bacteremia caused by Shigella in two adults with AIDS. In both patients, S. flexneri was recovered from stool and blood samples. The isolates belonged to serotype 6, were resistant only to trimethoprim-sulfamethoxazole and showed a similar band profile by pulsed-field gel electrophoresis. Patients received prolonged antimicrobial treatment with a favorable outcome. There were no cases of diarrhea in other individuals admitted to the emergency room. We hypothesized that patient No. 2 was infected at the hospital from patient No. 1. However, we could not establish the way of transmission. Although rare, it is important to take into account the possible occurrence of bacteremia due to Shigella or other bacterial enteropathogens in immunocompromised patients with diarrhea.

Shigella in Brazilian children with acute diarrhoea: prevalence, antimicrobial resistance and virulence genes.

Diarrhoeal disease is still considered a major cause of morbidity and mortality among children. Among diarrhoeagenic agents, Shigella should be highlighted due to its prevalence and the severity of the associated disease. Here, we assessed Shigella prevalence, drug susceptibility and virulence factors. Faeces from 157 children with diarrhoea who sought treatment at the Children's Hospital João Paulo II, a reference children´s hospital in Belo Horizonte, state of Minas Gerais, Brazil, were cultured and drug susceptibility of the Shigella isolates was determined by the disk diffusion technique. Shigella virulence markers were identified by polymerase chain reaction. The bacterium was recovered from 10.8% of the children (88.2% Shigella sonnei). The ipaH, iuc, sen and ial genes were detected in strains isolated from all shigellosis patients; set1A was only detected in Shigella flexneri. Additionally, patients were infected by Shigella strains of different ial, sat, sen and set1A genotypes. Compared to previous studies, we observed a marked shift in the distribution of species from S. flexneri to S. sonnei and high rates of trimethoprim/sulfamethoxazole resistance.

Bacteriemia por Shigellaflexneri serotipo 6 en pacientes con SIDA: Presentación de dos casos clínicos / Bacteraemia due to Shigella flexneri serotype 6 in two patients with AIDS

Infections due to Shigella usually remain localized to the digestive tract and are self-limited. Bacteremia is a potentially lethal complication that can occur in immunocompromised patients. We describe two episodes of bacteremia caused by Shigella in two adults with AIDS. In both patients, S. flexneri was recovered from stool and blood samples. The isolates belonged to serotype 6, were resistant only to trimethoprim-sulfamethoxazole and showed a similar band profile by pulsed-field gel electrophoresis. Patients received prolonged antimicrobial treatment with a favorable outcome. There were no cases of diarrhea in other individuals admitted to the emergency room. We hypothesized that patient No. 2 was infected at the hospital from patient No. 1. However, we could not establish the way of transmission. Although rare, it is important to take into account the possible occurrence of bacteremia due to Shigella or other bacterial enteropathogens in immunocompromised patients with diarrhea.

Las infecciones por Shigella spp., en general, permanecen localizadas en el tracto digestivo y tienen una evolución autolimitada. La bacteriemia es una complicación potencialmente letal que ocurre en pacientes con algún tipo de inmunocompromiso. Presentamos dos casos de bacteriemia causadas por Shigella en dos adultos con SIDA. En ambos pacientes, se recuperó Shigella flex-neri en muestras de deposiciones y sangre. Los aislados correspondieron al serotipo 6, fueron resistentes sólo a cotrimoxazol y mostraron un perfil de bandas similar por PFGE. Los pacientes recibieron tratamiento antimicrobiano prolongado y la evolución fue favorable. No se registraron otros casos de diarrea en individuos admitidos en el servicio de emergencia. La hipótesis fue que el paciente 2 adquirió la infección en el hospital a partir del paciente 1. Sin embargo, no pudimos establecer el modo de transmisión. Aunque poco frecuente, es importante tener presente la ocurrencia de bacteriemia por Shigella spp. o por otros enteropatógenos bacterianos en pacientes inmunocomprometidos con diarrea.

Shigella in Brazilian children with acute diarrhoea: prevalence, antimicrobial resistance and virulence genes

Diarrhoeal disease is still considered a major cause of morbidity and mortality among children. Among diarrhoeagenic agents, Shigella should be highlighted due to its prevalence and the severity of the associated disease. Here, we assessed Shigella prevalence, drug susceptibility and virulence factors. Faeces from 157 children with diarrhoea who sought treatment at the Children's Hospital João Paulo II, a reference children´s hospital in Belo Horizonte, state of Minas Gerais, Brazil, were cultured and drug susceptibility of the Shigella isolates was determined by the disk diffusion technique. Shigella virulence markers were identified by polymerase chain reaction. The bacterium was recovered from 10.8% of the children (88.2% Shigella sonnei). The ipaH, iuc, sen and ial genes were detected in strains isolated from all shigellosis patients; set1A was only detected in Shigella flexneri. Additionally, patients were infected by Shigella strains of different ial, sat, sen and set1A genotypes. Compared to previous studies, we observed a marked shift in the distribution of species from S. flexneri to S. sonnei and high rates of trimethoprim/sulfamethoxazole resistance.

The prevalence of swine enteropathogens in Brazilian grower and finish herds

Diarrhoea among growing and finishing pigs is an important problem in many herds. The prevalence of L. intracellularis, B. pilosicoli, B. hyodysenteriae, Salmonella spp., enterotoxigenic E. coli, Trichuris suis and the occurrence of mixed infection were investigated. Fecal samples for forty-six herds with diarrhea or a history of diarrhea were randomly collected in Minas Gerais state, Brazil. The enteric pathogens were detected by culture (E. coli and Salmonella sp.), PCR (L. intracellularis and Brachyspira spp.) and eggs counts (T. suis). The overall herd prevalence of L. intracellularis, Salmonella enterica serotype Typhimurium and enterotoxigenic E. coli were 19.56%, 6.52%, 10.86% respectively. Mixed infection was diagnosed in 30.43% of herds, and L. intracellularis and Salmonella enterica serotype Typhimurium are main pathogens association (10.87%). B. pilosicoli was diagnosed only in two herds, always associated with mixed infections. B. hyodysenteriae and T. suis were not demonstrated in any sample. These pathogens have been reported world-wide but studies regarding epidemiology in Brazil are few. This study contributes to establish of prevention programs for the control enteropathogens in grower finish herds in Brazil.