Etiology of bacterial diarrhea in large cities, mid-sized/small cities and rural areas of China / 中华流行病学杂志

Objective: To understand the etiological characteristics of bacterial diarrhea in different areas, including large cities, mid-sized/small cities and rural area, in China. Methods: A cross-sectional surveillance was conducted in 17 provinces of China from 2010 to 2014. The acute diarrhea outpatients were selected from clinics or hospitals in large cities, mid-sized/small cities, including rural-urban fringe zones, and rural areas. The demographical and clinical characteristics of the patients were collected by using questionnaire, and stool samples were taken from them for laboratory detection of 17 kinds of bacteria. The differences in pathogen positive rates (PPR) and pathogen spectrum across the cases from three-type areas were compared. The different infection risk in different cases were analyzed with unconditional logistic regression model. Results: In our study, we enrolled 9 253 cases from large cities, 5 138 cases from rural areas and 13 683 cases from midsized/small cites. The pathogen with largest differences in infection rate across the three-type areas was Shigella (S.) flexneri (rural area: 5.81%, mid-sized/small city: 2.78%, large city: 0.46%), followed by Aeromonas (A.) hydrophila (rural area: 2.14%, mid-sized/small city: 0.96%, large city: 0.48%). Compared with cases in large cities, the cases in mid-sized/small cities and rural areas had higher infection risks for S. flexneri (mid-sized/small city: OR=6.481, 95%CI: 4.666-9.002, rural area: OR=11.304, 95%CI: 8.018-15.938) and A. hydrophila (mid-sized/small city: OR=1.992, 95%CI:1.401-2.832, rural area: OR=4.083, 95%CI: 2.833-5.884). The constituent ratio of diarrheagenic Escherichia coli and Salmonella increased with the urbanization development, while the ratios of Shigella and A. hydrophila had an opposite trend. S. sonnei (60.00%) was the predominant serogroup of Shigella in urban infections, while S. flexneri (77.37%) was the predominant serogroup in rural infections. Conclusion: The differences in pathogen spectrum of bacterial diarrhea were obvious across large cities, mid-sized/small cities and rural areas in China, especially the differences in the infection rates of S. flexneri and A. hydrophila.

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)

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.

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.

Characterization of Shigella spp. by antimicrobial resistance and PCR detection of ipa genes in an infantile population from Porto Velho (Western Amazon region), Brazil

The incidence of Shigella spp. was assessed in 877 infants from the public hospital in Rondônia (Western Amazon region, Brazil) where Shigella represents the fourth cause of diarrhea. Twenty-five isolates were identified: 18 were Shigella flexneri, three Shigella sonnei, three Shigella boydii and one Shigella dysenteriae. With the exception of S. dysenteriae, all Shigella spp. isolated from children with diarrhea acquired multiple antibiotic resistances. PCR detection of ipa virulence genes and invasion assays of bloody diarrhea and fever (colitis) were compared among 25 patients testing positive for Shigella. The ipaH and ipaBCD genes were detected in almost all isolates and, unsurprisingly, all Shigella isolates associated with colitis were able to invade HeLa cells. This work alerts for multiple antibiotic resistant Shigella in the region and characterizes presence of ipa virulence genes and invasion phenotypesin dysenteric shigellosis.

Diferença de patogenicidade entre Escherichia coli enteroinvasora e Shigella flexneri em modelo experimental de infecção intestinal / Diference in pathogenicity between enteroinvasive Escherichia coli and Shigella flexneri in an experimental model of intestinal infection

Neste trabalho, esclarecemos tópicos da patogenicidade de EIEC que sustentam a sua menor virulência quando comparada à S. flexneri, e mostramos a importância das células dendríticas (CD) nesse processo. Estudou-se o comportamento de EIEC e S. flexneri quando em contato com células Caco-2, avaliando-se uma cinética de expressão dos genes envolvidos na invasão e disseminação bacteriana. Em geral, todos os genes foram menos expressos em EIEC, fato corroborado pelo fenótipo de disseminação bacteriana, onde EIEC foi menos eficiente do que Shigella. Também foi avaliada a modulação da resposta inflamatória de células dendríticas intestinais murinas pela produção de citocinas, expressão de moléculas co-estimulatórias e apresentação de antígenos, após desafio das células com as bactérias. Os resultados sugerem que EIEC induz a uma resposta protetora ao hospedeiro, enquanto que Shigella estaria "driblando" o sistema imune, além de provavelmente super-estimular o sistema imune adaptativo, fato que poderia levar a um agravamento da doença. As ações integradas das células Caco-2, células dendríticas e estímulos bacterianos foram estudadas em cocultura celular. Observou-se que EIEC e suas proteínas secretadas induzem a migração das CDs ao compartimento apical da co-cultura; nada foi observado quando o desafio se deu com Shigella...

Opciones de tratamiento en shigelosis / Treatment of shigellosis

La Shigella es una bacteria aeróbica Gram negativa que no fermenta la lactosa. Se considera la primera causa de disentería en nuestro país al igual que en todos los países subdesarrollados. Existen 4 especies que causan enfermedad gastrointestinal: S. dysenteriae (serogrupo A), S. fl exneri (serogrupo B), S. boydii (serogrupo C) y S. sonnei (serogrupo D). La S. fl exneri es la principal causa de shigellosis endémica en los países subdesarrollados. La S. dysenteriae es la que produce una potente citotoxina (toxina shiga), causa una enfermedad más severa, prolongada y fatal. Al mismo tiempo la resistencia antimicrobiana es más frecuente con esta especie.

Brote de shigellosis en una escuela de educación básica / Shigella outbreak in an elementary school

Se analiza un brote de gastroenteritis por shigella sonnei, ocurrido en una escuela básica de una comuna de Santiago, en marzo de 1997. En esta escuela, con una matricula de 1470 niños entre 5 y 14 años de edad, 350 se beneficiaban con el programa de alimentación escolar (pae) y almorzaban en el establecimiento. Treinta y cinco de los 350 niños del pae presentaron simultáneamente gastroenteritis que motivó consulta en un servicio de emergencia, 2 de los cuales presentaron diarrea con sangre requiriendo hospitalización. Durante los cinco días posteriores se registraron 189 nuevos casos en la escuela. Frente a la notificación, se efectuó visita epidemiológica a la escuela, obteniéndose muestras de deposición para estudio de bacterias y virus enteropatógenos en 65 niños sintomáticos y en los tres manipuladores de alimentos. Se identificó s. sonnei en 20,5 porciento de los coprocultivos y todas las cepas tenían el mismo antibiotipo. La búsqueda de virus entéricos (rotavirus, calcivirus) dio resultados negativos. En los manipuladores de alimentos no se detectó enteropatógenos bacterianos ni virales. La presentación del brote plantea una toxiinfección por s. sonnei, iniciada probablemente por ingestión de alimentos (tasa de ataque primario 10 porciento) y luego transmisión persona a persona (tasa de ataque secundario 16,9 porciento) Para controlar el brote se reforzaron medidas de higiene personal y de saneamiento ambiental a través de educación a toda la comunidad escolar y el control sanitario del establecimiento. A partir del quinto día de iniciado el primer caso, se administró cotrimoxazol, durante cinco días, sólo a los casos sintomáticos. El brote se controló al noveno día

Papel de Shigella spp en un estudio controlado de enfermedad diarréica aguda

Para determinar el papel de shigella spp en un sector de la población infantil, se realizó un estudio descriptivo entre 250 pacientes pediátricos con síntomasn característicos de Enfermedad diarréica aguda (EDA) que consultaron al servicio de urgencias de la clínica del niño en la ciudad de Santafé de Bogotá en los meses de enero a abril de 1999. La información clínica, epidemiológica y de laboratorio, incluida en el estudio fue: edad, sexo, tiempo de evolución, sangre en la deposición, fiebre, vómito, grado de deshidratación, dolor abdominal, leucocitos en heces, parásitos y azúcares reductores. Las muestras de heces se incubaron durante 4-6 horas a 37 grados centigrados en un caldo de enriquecimiento para gram negativos (GN). A partir del caldo GN se realizaron subcultivos en los agares convencionales para bacterias entéricas; las colonias sospechosas se identificaron por pruebas bioquímicas y serológicas convencionales. A las cepas identificadas como Shigella se les realizaron pruebas de susceptibilidad antimicrobiana por el método de Bauer & Kirby. El procentaje de Shigella spp encontrado en el estudio fue del 4 por ciento. Un 50 pro ciento correspondió a S. sonnei, un 30 por ciento perteneció a S. dysenteriae y un 20 por ciento a S. flexneri. La suceptibilidad antimicrobiana de Shigella sppp demostró una alta resistencia a trimetoprin sulfametoxazole (90 por ciento),y una alta sensibilidad frente a ciprofloxacina (100 por ciento), imipemem (100 por ciento), ceftriaxona (90 por ciento) y cloramfenicol (70 por ciento). El estudio permite concluir que la incidencia de shigella entre los pacientes de la población pediátrica del centro estuadiado fue del 4 por ciento, con un predominio de shigella sonnei.

Fulminant toxic shigella encephalopathy

Bacillary dysentery due to Shigella is still one of the major causes of acute diarrhoeal disease, especially among children in the developing countries. Often, shigellosis is self-limiting and dose not pose a problem in the treatment of patients successfully. But occasionally, it may cause bacteremia or neurological complications which may be fatal. We report a case of fulminant encephalopathy caused by shigella dysenteriae type I, which has been described to produce an exotoxin which is a neurotoxin

Multirresistencia antimicrobiana en cepas de shigella sp en una comuna semi rural del área norte de Santiago / Antimicrobial multiresistance of shigella sp strains in a semi rural community of north Santiago

Appropriate antimicrobial therapy shortens the duration of Shigellosis and significantly reduces the risk of transmission. Shigella strains resistant to common antimicrobials have increased during the past years, determining the need for a periodic surveillance, to guide effective therapy. Aim: To report the results of a surveillance program in a rural community near Santiago (Colina), for Shigella infections. Material and methods: Between 1995 and 1997, stool samples from 3,534 episodes of diarrhoea, that occurred in Colina, were obtained. Two hundred twenty six Shigella strains were isolated and studied for susceptibility to ampicilin (AM), amoxicillin/clavulanic acid (AMC), cotrimoxazole (STX), chloramphenicol (CAF), tetracycline (TET), furazolidine (FU), ciprofloxacine (CIPR), nalidixic acid (AC NAL), gentamycin (GENT) and cefotaxime (CFTX). Results: Shigella flexnerii represented 134 of 226 Shigella strains isolated. All strains were susceptible to CIPR, AC NAL, GENT and CFTX. Yearly variation of resistance patterns to other antimicrobials were observed for these strains. Resistance to AM varied from 56 to 76 percent, to AMC from 25 to 56 percent, to STX from 21 to 47 percent, to CAF from 36 to 39 percent, to TET from 44 to 78 percent and to FU from 9 to 18 percent. Overall resistance was higher during 1997. All 85 strains of S sonnei were susceptible to CIPR, AC NAL and CFTX. Resistance throughout the years varied from 56 to 88 percent for AM, from 0 to 28 percent for AMC, from 44 to 53 percent for STX, from 11 to 40 percent for CAF, from 11 to 42 percent for TET and from 5 to 11 percent for FU. Overall resistance was also higher during 1997, except for AM and STX. Seven S boydii strains were isolated, only during 1995. All seven were resistant to AM and TET and none were resistant to FU, CIPR, AC NAL and CFTX. One strain was resistant to AMC, STX and CAF. Conclusions: Antimicrobial resistance patterns of Shigella sp isolated in Colina have increased from 1995 to 1997, specially for commonly used antimicrobials. Resistance remains low for furazolidine and all strains remain susceptible to quinolones

Infectious diarrhoea--an update.

Infectious diarrhoea is one of the most common illness affecting mankind. Recent advancement have led to detailed understanding of causative agents and the pathogenesis of the infections. Fluid and electrolyte replacement remains the most important aspect of treatment. The role of antimicrobial agents is discussed.

Shiguelose: diagnóstico e tratamento / Shiguellosis: diagnosis and therapy

É uma doença diarréica aguda infecciosa mundialmente distribuída, causada por um bacilo gram-negativo da família das enterobactérias, transmitido por contato inter-humano, por água e alimentos contaminados, causando diarréia mucopiossanguinolenta, associada à febre, cólicas abdominais, urgência e tenesmo retal. O diagnóstico é baseado na história clínica e exame físico, sendo confirmado principalmente pela coprocultura e, mais raramente, pela hemocultura. Outros exames inespecíficos podem ser usados, como o hemograma e a análise do mucofecal. A sorologia e o PCR podem ser úteis, porém nem sempre facilmente disponíveis. O tratamento visa a correçÝo dos distúrbios hidroeletrolíticos já que a shiguelose costuma ser autolimitada, sendo porém, eventualmente necessário o uso de antimicrobianos. Quando a shiguela isolada se mostra sensível à ampicilina, esta droga tem sido utilizada como primeira escolha; entretanto, nÝo se isolando o agente causal, o sulfametoxazoltrimethopim pode ser indicado. atualmente, os melhores resultados (e com baixos ídices de resistência) têm sido obtidos com o uso das quinolonas, devendo, porém, ser usadas com critério devido ao aparecimento de cepas multirresistentes.

Características gerais de enteropatógenos bacterianos / Bacterial enteropathogens: general characteristics

Este trabalho realiza uma revisäo sobre os principais enteropatógenos bacterianos, enfocando principalmente aspectos de sistemática, fatores de virulência e algumas características fisiológicas

Incidencia de Salmonella, Shigella y Escherichia coli enteropatógena, 1986-1993, en el Instituto Nacional de Pediatría / Incidence of Salmonella, Shigella y enteropathogene Escherichia coli, 1986-1993, at the Instituto Nacional de Pediatría

La gastroenteritis infecciosa constituye uno de los principales problemas de salud en casi todos los países de la América Latina. La Organización Mundial de la Salud reporta a las enfermedades diarreicas como una de las tres principales causas de defunsión en niños menores de 5 años, su etiología puede ser bacteriana, viral o parasitaria. Entre los agentes bacterianos se encuentran con mayor frecuencia especies de Salmonella, Shigella y E. coli enteropatógena y otras de menor frecuencia, como lo son Yersinia, Compylobacter, Plesiomonas, Aeromonas y Vibrio. El presente trabajo se ralizó con el fin de detectar a los agentes infecciosos clásicos (E. coli enteropatógena, Shigella y Salmonella). Durante 8 años se analizaron 22 519 muestras de materia fecal de pacientes del Instituto Nacional de Pediatría, resultado E. coli enteropatógena como la más frecuente con un 7 por ciento, seguida de Salmonella con 6 por ciento y Shigella 3 por ciento. Los serotipos más frecuentes de E. coli fueron 0111, 026 y 055, para Salmonella se observó el serogrupo B y en Shigella el serogrupo B (S. flexneri) también fue el más frecuente. Se observó infección múltiple en un 0.27 por ciento, Salmonella presentó resistencia a ampicilina, cefalotina y cloranfenicol. Shigella fue resistente a ampicilina, cefalotina, piperacilina y trimetoprim/sulfametoxasol