Caracterización molecular de aislamientos de Shigella sonnei recuperados en el programa de vigilancia por el laboratorio de la enfermedad diarreica aguda en Colombia / Molecular characterization of Shigella sonnei isolates recovered by the Laboratory Surveillance Program for Acute Diarrheal Disease in Colombia

Introducción. En Colombia, Shigella sonnei es uno de los serotipos más frecuentemente aislados (53,4 %) de muestras clínicas humanas asociadas a la enfermedad diarreica aguda. La identificación de patrones de restricción del ADN mediante electroforesis en gel de campo pulsado constituye la base de la vigilancia molecular de S. sonnei . Objetivo. Establecer la base de la vigilancia molecular de S. sonnei en Colombia mediante electroforesis en gel de campo pulsado. Materiales y métodos. Se estudiaron 102 de los 2.048 aislamientos de S. sonnei remitidos por la Red Nacional de Laboratorios entre 1997 y marzo del 2013; la selección se hizo de acuerdo con el patrón de resistencia antimicrobiana, el origen de la muestra y la relación con brotes. Se determinó el patrón genético mediante electroforesis en gel de campo pulsado con las enzimas de restricción XbaI y Blnl, según el protocolo de la red PulseNet International. El análisis de los patrones electroforéticos se hizo con el programa GelCompar II, versión 4.0. Resultados. Se obtuvieron 42 patrones electroforéticos con una similitud de 70 a 100 %. El patrón más frecuente fue COIN08J16X01.0017 (17,6 %), seguido por los patrones COIN04J16X01.0004 (9,8 %) y COIN02J16X01.0002 (5,8 %), y el 66,8 % restante se asoció con otros patrones electroforéticos. El análisis de brotes demostró la relación genética de cada brote con 100 % de similitud en la identificación; el patrón más frecuente en los brotes fue el COIN08J16X01.0017 (17,1 %). Conclusión. Se estableció la base de datos genotípicos de aislamientos de S. sonnei a nivel nacional mediante electroforesis en gel de campo pulsado; se incluyeron los 42 patrones únicos identificados en este estudio.

Introduction: In Colombia, Shigella sonnei is one of the most frequently isolated serotypes (53.4%) in human clinical samples associated with diarrheal acute disease. The identification of DNA restriction patterns by pulsed field gel electrophoresis is the basis for the molecular surveillance of S. sonnei . Objective: To establish the basis for the molecular surveillance of S. sonnei in Colombia using pulsed-field gel electrophoresis. Materials and methods: We studied 102 of 2,048 S. sonnei isolates referred by the National Laboratory Network between 1997 and March, 2013; the selection was made according to the antimicrobial multiresistance profile, the source of samples, and the relation to outbreaks. The genetic profile was determined by pulsed field gel electrophoresis using the restriction enzymes XbaI and BlnI in accordance with the PulseNet International protocol. The electrophoretic patterns were analyzed with the GelCompare II, version 4.0 software. Results: We obtained 42 electrophoretic patterns with a 70% to 100% similarity. The most frequent pattern was COIN08J16X01.0017 with 17.6%, followed by patterns COIN04J16X01.0004 with 9.8%, and COIN02J16X01.0002 with 5.8%, while the remaining 66.8% was associated with other electrophoretic patterns. The analysis of 10 outbreaks demonstrated their genetic relation with a 100% of similarity; the most frequent pattern in outbreaks was COIN08J16X01.0017 with 17.1%. Conclusion: The genotypic database for Shigella sonnei isolates was established using pulsed field gel electrophoresis including the 42 unique patterns identified in this study.

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

Drug resistance profiles and clonality of sporadic Shigella sonnei isolates in Ankara, Turkey

The aims of this study were to investigate drug resistance rates, types of extended spectrum beta lactamases (ESBLs), and molecular epidemiological characteristics of 43 Shigella sonnei isolates. Ampicillin-sulbactam, amoxicillin-clavulanate, chloramphenicol, and ciprofloxacin were the most active antibiotics. Five isolates harbored blaSHV-12, blaTEM-1 and blaCTX-M-15. More than 90% of the isolates had an indistinguishable pulsotype.

Patrones de susceptibilidad antimicrobiana de cepas de Shigella sonnei aisladas durante tres períodos diferentes en la Región Metropolitana, Chile / Antibiotic susceptibility patterns among Shigella sonnei, isolated during three different periods in Región Metropolitana, Chile

Background: Shigella sonnei gastroenteritis improves clinically and microbiologically with antibacterial treatment; however choosing a useful drug is a universal challenge because of in vitro susceptibility of S. sonnei frequently evolves to be resistant. Objective: To evaluate in vitro susceptibility of S. sonnei strains isolated from patients attending at the Chilean Región Metropolitana and to know the evolution that resistant patterns of S. sonnei have experienced. Material: In this study, the antimicrobial susceptibility profile of 277 isolates of Shigella sonnei was compared. The analyzed periods of time were: period I (1995-1997) 85 strains; period II (2004-2006) 92 strains and period III (2008-2009) 100 strains, in Santiago, Chile. The method performed to analyze susceptibility patterns was the disc diffusion (Kirby-Bauer). Results: The strains showed rates of resistance to ampicillin: period I, 85.8%; period II, 53.3%; period III, 100%, trimethoprim/sulfamethoxazole: period I, 50.5%; period, II 46.7%; period III, 100%, chloramphenicol: period I, 36.4%; period II, 12%; period III, 100% and tetracycline: period I, 38.8%; period II, 30.4%; period III, 100%. 98.9% of the strains showed susceptibility to quinolones. Significant differences were observed in patterns of antimicrobial resistance for both individuals and for multidrug resistance (≥ 3 antimicrobials) in the three periods (p < 0.001, χ2 test). Of all resistant strains, 17% were resistant to 1 or 2 antibiotics, while 65.7% showed a pattern of multidrug resistance; 100% of the period III strains presented multidrug resistance. Conclusion: These results showed the temporal resistance dynamics of S. sonnei circulating strains in the Chilean Región Metropolitana. Due to the endemic behavior of shigellosis in Chile, it is urgent to maintain permanent surveillance of antimicrobial resistance profiles to improve both prevention and treatment of shigellosis.

Introducción: La infección entérica producida por Shigella sonnei mejora clínicamente y microbiológicamente con antibioterapia; sin embargo, la elección del antimicrobiano es un problema universal pues la susceptibilidad in vitro de S. sonnei evoluciona frecuentemente hacia la resistencia. Objetivo: Evaluar la susceptibilidad in vitro a antimicrobianos de S. sonnei y conocer la evolución que han experimentado los patrones de resistencia de cepas aisladas de cuadros clínicos en pacientes de la Región Metropolitana, Chile. Material y Métodos: Se comparó el perfil de susceptibilidad a antimicrobianos, de 277 cepas clínicas de S. sonnei aisladas durante tres períodos: período I (1995-1997) 85 cepas; período II (2004-2006) 92 cepas y período III (2008-2009) 100 cepas, en Santiago, Chile. El perfil de susceptibilidad a antimicrobianos se determinó mediante test de difusión en agar. Resultados: Las tasas de resistencia de las cepas en los periodos I, II y III respectivamente fueron: ampicilina: 85,8%; 53,3%; 100%, cotrimoxazol: 50,5%; 46,7%; 100%, cloranfenicol: 36,4%; 12%; 100% y tetraciclina: 38,8%; 30,4%; 100%. El 98,9% de las cepas fue susceptible a quinolonas. Se observó diferencias significativas en los porcentajes de resistencia para antimicrobianos individuales y multi-resistencia (≥ 3 antimicrobianos) en los tres períodos (p < 0,001; Test de χ2). De las cepas resistentes, 17% presentó resistencia a uno ó dos antimicrobianos, 65,7% mostró multi-resistencia antimicrobiana. El 100% de las cepas del período III presentó multi-resistencia. Discusión: Estos resultados evidencian la dinámica temporal de la resistencia en cepas de S. sonnei circulantes en la Región Metropolitana. Dado que en Chile la shigelosis tiene un carácter endémico, es prioritario mantener una vigilancia constante de los perfiles de resistencia a antimicrobianos, para mejorar la prevención y el tratamiento de la shigelosis.

Colicin type 7 produced by majority of Shigella sonnei isolated from Thai patients with diarrhoea

Thirty one out of 153 strains of Shigella sonnei isolated from Thai patients with diarrhoea showed antibacterial activity against S. sonnei by agar well diffusion method. All of them harbor plasmids with the genetic determination of colicin type 7 (Js) gene but without colicin E and colicin U gene. The PCR product obtained from strain 35/44 was shown to be the gene for colicin type 7 lytic protein (cja). The partially purified bacteriocin (PPB) containing colicin type 7 of strain 35/44 was prepared and used for characterization. The antibacterial activity of PPB against a total of 17 selected Gram-positive and Gram-negative bacteria was tested. It was found that PPB of strain 35/44 was active against E. coli O157, S. sonnei and S. boydii. The sensitivity of PPB from this strain to proteinase K, trypsin and α-chymotrypsin suggests the proteinaceous nature of these antimicrobial substances. Therefore, this isolated bacterium can be regarded as bacteriocin producing bacteria. The bacteriocin produced by this isolated S. sonnei was heat stable as evidenced by its ability to maintain the activity at 80 °C for 60 min. In addition, it was stable within a wide range of pH (3-9). The molecular weight of colicin type 7 from isolated S. sonnei strain 35/44 analyzed by SDS-PAGE was 54.4 kDa composing of at least five subunits. It is to our knowledge; the first report of Thai patients with diarrhoea that S. sonnei isolated from them contained colicin type 7.

[ investigation of molecular epidemiology of Shigella soneii isolated from clinical cases in Tehran using RAPD-PCR method]

Bloody diarrhea [Shigellosis] is caused by different species of Shigella and is often seen in children befor than under 15 years old must be aded. less than 15 years of age. This disease is extremely contagious, epidemic and endemic in communities with low level hygiene and in majority of cases is accompanied with hemolytic uremia syndrome and decreased children's growth. As the rate of infection by Shigella soneii among different ranges of age is considered as an indicator of hygiene level, this study was designed to detect the rate of infection by Shigella soneii among different ranges of ages in Tehran by Random Amplified Polymorphic DNA [RAPD-PCR] between 2002-2006. In this study totally 60 isolates of Shigella soneii taken from 36 [60%] boys and 24 [40%] girls were studied. All isolates were primary confirmed as Shigella species by biochemical [Motility, MR, Citrate, H[2]S, Indole, Lysin decarboxylase, Ornitin decarboxylase, ONPG] and serologic tests; then all isolates were finally confirmed as Shigella soneii by Random Amplified Polymorphic DNA [RAPD-PCR] test. Among all 60 patients, the highest rate of infection with Shigella soneii belonged to 1-2 year-old group [36/7%]. Furthermore, the lowest rate of infection belonged to group with more than 9 years of age [1/6%]. This study showed that RAPD PCR method had a relative good discrimination power, and was a good method for typing of Shigella isolates in molecular epidemiological studies according to its high discrimination power, typing ability, reproducibility, low cost, rapidity and easy of use

Fatality due to shigellosis with special reference to molecular analysis vi Shigella sonnet strains isolated from the fatal cases

Shigellosis as a global human health problem is more severe than other forms of gastroenteritis and causes over a million deaths in developing countries worldwide annually. Fatality due to shigellosis is usually due to dehydration and two-third of fatalities are seen among children. The aim of current study was to describe fatal cases of shigellosis due to infection with Shigella sonnei and S.flexneri. We investigated the fatal cases of shigellosis among all children with acute diarrhea admitted to Children's Medical Center, Tehran, Iran. Bacterial isolation and identification was achieved according to standard bacteriological methods. Antibiotic susceptibility tests, plasmid profiling and ribotyping were performed to investigate the clonal relationship among the isolates. Among 1200 children with acute diarrhea, 140 [12.7%] cases had shigellosis. Of these, three patients died. No signs of severe dehydration were observed among the fatal cases. The symptoms were not improved following antibiotic therapy and all three cases died after 24 h of hospitalization despite receiving intensive treatments. Stool cultures yielded S.flexneri and S. sonnei for one and two cases, respectively. The isolates were resistant to streptomycin, ampicillin, and sulfamethoxazole-trimethoprim. 5. sonnei strains were further studied and showed a single pattern of antibiotic susceptibility and ribotyping. Mortality due to species other than 5. dysenteriae is rare, however, in current study we found S. sonnei and S.flexneri as the cause of fatality among pediatric patients during the study

Increased isolation and characterization of Shigella sonnei obtained from hospitalized children in Tehran, Iran.

Shigella flexneri has been the most frequent cause of shigellosis in children in Iran. To evaluate the changes in frequency of serogroups, 302 Shigella species were isolated in 2003 from hospitalized children, aged less than 12 years, with acute diarrhoea in Tehran, Iran. The number of collected S. sonnei, S. flexneri, S. boydii, and S. dysenteriae isolates was 178 (58.9%), 110 (37.4%), 10 (3.3%), and 4 (1.3%) respectively. Most (94%) S. sonnei isolates were resistant to co-trimoxazole. They were, however, relatively or completely sensitive to 15 commonly-used antibiotics. The extracted plasmids showed 12 different profiles with two closely-related patterns constituting 70% of the total isolates. Ribotyping, using PvuII, HindIII or SalI restriction enzymes, generated a single pattern for all S. sonnei isolates. Data suggest that S. sonnei has become the predominant serogroup in children in the hospitals of Tehran.

Epidemiological characterization of resistance and PCR typing of Shigella flexneri and Shigella sonnei strains isolated from bacillary dysentery cases in Southeast Brazil

Shigella spp are Gram-negative, anaerobic facultative, non-motile, and non-sporulated bacilli of the Enterobacteriaceae family responsible for "Shigellosis" or bacillary dysentery, an important cause of worldwide morbidity and mortality. However, despite this, there are very few epidemiological studies about this bacterium in Brazil. We studied the antibiotic resistance profiles and the clonal structure of 60 Shigella strains (30 S. flexneri and 30 S. sonnei) isolated from shigellosis cases in different cities within the metropolitan area of Campinas, State of São Paulo, Brazil. We used the following well-characterized molecular techniques: enterobacterial repetitive intergenic consensus, repetitive extragenic palindromic, and double-repetitive element-polymerase chain reaction to characterize the bacteria. Also, the antibiotic resistance of the strains was determined by the diffusion disk method. Many strains of S. flexneri and S. sonnei were found to be multi-resistant. S. flexneri strains were resistant to ampicillin in 83.3 percent of cases, chloramphenicol in 70.0 percent, streptomycin in 86.7 percent, sulfamethoxazole in 80.0 percent, and tetracycline in 80.0 percent, while a smaller number of strains were resistant to cephalothin (3.3 percent) and sulfazotrim (10.0 percent). S. sonnei strains were mainly resistant to sulfamethoxazole (100.0 percent) and tetracycline (96.7 percent) and, to a lesser extent, to ampicillin (6.7 percent) and streptomycin (26.7 percent). Polymerase chain reaction-based typing supported the existence of specific clones responsible for the shigellosis cases in the different cities and there was evidence of transmission between cities. This clonal structure would probably be the result of selection for virulence and resistance phenotypes. These data indicate that the human sanitary conditions of the cities investigated should be improved.

Experimental study on the antibacterial effect of origanum volatile oil on dysentery bacilli in vivo and in vitro / 华中科技大学学报（医学）（英德文版）

To observe the germistatic and germicidal effects of origanum volatile oil (OVI) on the dysentery bacteria, the abdominal cavity of mice was infected with Shigella sonne (Sh. sonnei) and Shigella flexneri (Sh. flexneri) F2a. After OVI was given to the mice via gastric lavage, the effects of OVI on the infected mice were observed. The minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) for dysentery bacteria were determined in vitro. The results showed that origanum volatile oil showed obvious protective effect on mice infected with Sh. sonnei and Sh. flexneri F2a and it had germistatic and germicidal effects on dysentry bacteria. We are led to conclude that origanum volatile oil is an effective medicine against the infection of dysentery bacteria.

Validation of salmonellosis and shigellosis diagnostic test kits at a provincial hospital in Thailand.

Rapid Diagnosis of salmonellosis and shigellosis was performed using six different diagnostic test kits which recently have been made available commercially. They were Salmo-Dot, Typhi-Dot, Shigel Dot A, B, C, and D test kits for detection of Salmonella spp., group D salmonellae, and groups A, B, C, and D Shigella spp., respectively. The principle of all test kits is a membrane (dot) ELISA using specific monoclonal antibodies to the respective pathogens as the detection reagents. The present study was designed to validate the accuracy of the test kits, at a laboratory in a provincial hospital in Thailand, in comparison with the conventional bacterial culture method alone or with the combined results of the culture and the Western blot analysis (WB) for detecting the respective bacterial lipopolysacchharides (LPS) in specimens. Five hundred rectal swab samples of patients with diarrhea who seeked treatment at the hospital, were evaluated. The diagnostic accuracy of the Salmo-Dot was 91.0% when compared with the conventional bacterial culture method alone but was 100.0% in comparison with the combined results of the culture and the WB. The Typhi-Dot and the Shigel-Dot A, B, C, and D showed 100%, 99.2%, 95.0%, 94.0% and 96.4%, respectively when compared with the culture alone and all were 100% in comparison with the combination of the results of the bacterial culture and the WB. The Shigel-Dot A revealed antigen of type 1 Shigella dysenteriae in several specimens in which the bacteria could not be recovered by the culture method. This difference is important as type 1 Shigella dysenteriae have high epidemic potential and often cause severe morbidity. Unawareness of their presence by the conventional culture may have great impact on disease surveillance for public health. The pathogen detection using the six diagnostic test kits is sensitive, specific, rapid, and relatively simple and less expensive. Several specimens can be tested at the same time without much increase in turn around time. Moreover, these kits produce no contaminated waste as compared with the bacterial culture method. The test kits should be used for rapid screening of specimens of patients with diarrhea especially in areas where culture facilities are inadequate.

Patrones de sensibilidad in vitro y comportamiento clínico de shigella / Susceptibility patterns and clinical presentation of shigella

Shigella mantiene un importante lugar como causa de diarrea en niños con aumento de su resistencia antimicrobiana en los últimos años, lo que dificulta la elección de terapia empírica en cuadros disentéricos. Se estudió la susceptibilidad antimicrobiana in vitro a 163 cepas aisladas entre 1997 y 1999. S. sonnei representó el 63 por ciento de las cepas aisladas. Se observó aumento en los patrones de resistencia de Shigella a los antimicrobianos tradicionales. La resistencia global de las cepas alcanzó a 95 por ciento para ampicilina, 84 por ciento para cloranfenicol, 43,6 por ciento para cotrimoxazol y 3,7 por ciento para furazolidona; no hubo resistencia a ciprofloxacina. De 57 niños hospitalizados por shigelosis, 82,5 por ciento tenían sobre 2 años de edad. Todos presentaron fiebre, 56 por ciento disentería y 8,8 por ciento convulsiones. Seis pacientes con evolución tórpida recibieron ciprofloxacina con éxito clínico. Ciprofloxacina representa una alternativa a evaluar como terapia empírica en niños con disentería de causa bacteriana. Es necesario mantener vigilancia local en la susceptibilidad antimicrobiana de Shigella a fin de guiar su terapia específica

Vigilancia de la resistencia a los antibacterianos en Argentina: programa WHONET, 1995-1996 / Monitoring antimicrobial resistance in Argentina: the WHONET program, 1995-1996

La Organización Mundial de la Salud ha puesto en marcha un programa para la vigilancia de la resistencia a los antibacterianos, denominado WHONET, que se desarrolló en Argentina mediante una red de 23 laboratorios de instituciones hospitalarias públicas y privadas sometidos a programas nacionales e internacionales de control de calidad. Entre enero de 1995 y diciembre de 1996 se determinó por el método de difusión en agar la sensibilidad a los antibacterianos de 16.073 aislados clínicos consecutivos, siguiendo las recomendaciones del Comité Nacional de Estándares para Laboratorios Clínicos (National Committee for Clinical Laboratory Standards: NCCLS) de los Estados Unidos de América. Más de la mitad de los aislados urinarios de Escherichia coli fueron resistentes a la ampicilina, y más de 30 por ciento a la trimetoprima-sulfametoxazol. Cuando se comparó la sensibilidad de los aislados urinarios de pacientes ambulatorios y hospitalizados, se observó una marcada diferencia en los perfiles de actividad (porcentaje de microorganismos resistentes aislados en pacientes hospitalizados frente a pacientes ambulatorios) de la gentamicina (8 por ciento frente a 2 por ciento), la norfloxacina (6 por ciento frente a 2 por ciento) y las cefalosporinas de tercera generación (18 por ciento frente a 10 por ciento). Los aislados de Klebsiella pneumoniae recuperados de hemocultivos presentaron resistencia a las cefalosporinas de tercera generación y a la gentamicina en 71 y 60 por ciento de los casos, respectivamente. La proporción de Staphylococcus aureus resistentes a la oxacilina fue de 39 por ciento. Cerca de la mitad de los aislados de Enterococcus spp. presentaron resistencia de alto nivel a los aminoglucósidos, pero no se detectó resistencia los glicopéptidos. En nuestro medio, la ampicilina y la trimetoprima-sulfametoxazol no fueron apropiadas para el tratamiento de las diarreas; Shigella flexneri presentó mayor porcentaje de aislados resitentes a ambos fármacos (87 y 74 por ciento, respectivamente) que Shigella sonnei (47 y 71 por ciento, respectivamente). Se detectó resistencia a las cefalosporinas de tercera generación en 40 por ciento de los aislados de Salmonella spp. recuperados en hospitales pediátricos. En casos de meningitis bacteriana, las tasas de resistencia de Streptococcus pneumoniae a la penicilina (18 por ciento) y de Haemophilus influenzae a la ampicilina (19 por ciento) se situaron en el rango intermedio de las descritas en países

Frecuencia y biodiversidad de algunas bacterias enteropatógenas aisladas en niños con síndrome diarreico agudo / Frequency and biodiversity of some enteropathogenic bacteria recovered from children with acute diarrheic syndrome

El estudio etiológico de la diarrea aguda en el niño se ve limitado por las técnicas actualmente disponibles con fines clínicos. La aplicación de técnicas de biología molecular en el análisis de deposiciones permite incrementar la detección de enteropatógenos y una caracterización fenotípica más acabada de las cepas aisladas permite describir mejor su diversidad y caracterizar epidemiológicamente los episodios observados en cada temporada estival. En un estudio piloto efectuado en la ciudad de Concepción, se aplicaron en el estudio etiológico de la diarrea en niños entre 0 y 4 años de edad consultantes en un servicio de urgencia, las técnicas convencionales de cultivo e identificación por pruebas bioquímicas según Edwards y Ewing, la búsqueda de genes de virulencia de Escherichia coli enterohemorrágica más el análisis de serotipo, biotipo, antibiotipo y perfil plasmidial de las cepas enteropatógenas aisladas. En 32 (25,3 por ciento) de 127 niños con diarrea de edad entre 5 meses y 4 años de detectó la frecuencia de los siguientes enteropatógenos: Shigella sonnei 13,4 por ciento Shigella flexneri 6,3 por ciento, Yersinia enterocolitica 2,4 por ciento, Shigella boydii 0,8 por ciento, Salmonella typhimurium 1,6 por ciento y Salmonella hadar 0,8 por ciento. La frecuencia de aislamiento aumentó en relación al aumento de la edad desde 0 por ciento en el grupo etario de 4 a 5 meses, 6,3 por ciento en el de 6 a 11 meses, 33,1 por ciento en el de 12 a 23 meses, hasta 68,7 por ciento en el grupo de 24 a 47 meses. Shigella spp. fueron las de mayor frecuencia relativa de aislamiento con 81,1 por ciento. El rendimiento de las determinaciones feno y genotípicas para estudio de biodiversidad fue variable en las especies. Las 8 cepas de S. flexneri se diferenciaron en 6 grupos en base a 3 serotipos, 5 antibiotipos y 5 perfiles plasmidiales. Las 17 cepas de S. sonnei se discriminaron en 11 grupos determinados preferentemente por los patrones plasmidiales. La amplificación aleatoria mediante RAPD en S. flexneri y S. sonnei no aportó mayor grado de biodiversidad que la establecida por las otras determinaciones. El antibiotipo y perfil plasmidial fueron útiles en discriminar en 2 grupos las 3 cepas de Y. enterocolitica, marcadores que además permitieron sugerir que las S. typhimurium aisladas serían una misma cepa

Aislamientos de Shigella y Salmonella durante el período 1990-1994 / Isolation of Shigella and Salmonella during the period 1990-1994

En el siguiente trabajo se comunican los aislamientos de Shigella y Salmonela en pacientes con diarreas agudas que fueron atendidos en el Hospital de Niños Ricardo Gutierrez de la ciudad de Santa Fe en el período 1990-1994. Shigella prevaleció en cada uno de los años estudiados con respecto a Salmonella, y el serogrupo predominante fue flexneri. La recuperación de Salmonella fue similar en cada año, debiéndose destacar un brote intrahospitalario a Salmonella typhimurium. Es importante conocer los agentes más frecuentes para que las medidas de control sean dirigidas y permitan orientar investigaciones futuras relacionadas con las enfermedades diarreicas

Diarreia causada por Shigella: aspectos clinicos e terapeuticos / Diarrhea caused by Shigella: clinical and therapeutical aspects

Os autores estudaram diarreias graves causadas por Shigella sp que foram atendidas no Servico de Emergencias do Hospital Universtario da USP durante tres anos. Esse agente foi isolado de 65 casos de diarreia aguda que corresponderam a 3,1 por cento dos casos graves e 22,3 por cento dos quadros clinicos de disenteria. A S.flexneri foi a mais isolada, seguida pela S.sonnei, na proporcao de 3:1...

Shigella isolates in stool.

A total of 447 Shigella strains were isolated from stool samples during 1989-1991. Of these 270 (60%) were from children. Among the different species and serotypes Sh. flexneri 60 (13.4%) and Sh. sonnei Phage 139 (65%) were the most frequently isolated strains. 154 (34.4%) strains were resistant to three and 179 (40%) to more than three antibiotics. Some strains of Shigella were found to be resistant to furazolidine and neomycin.

Characterization of Shigella sonnei strains from three different geographical locations

Colicin typing, biotyping, phase typing and in vitro antimicabial susceptibility testing were performed on clinical isolates of Shigella sonnei from three different geographical locations. Results of 93 strains from Kuwait, 61 strains from Saudi Arbia and 23 strains from Bangladesh were compared. Of 169 strains of S. sonnei tested, 75% belonged to colicin type 6/11. It was the most common colicin type in all three countries However, differences in antimicrobial susceptibility patterns were observed. The resistance pattern in 62% of resistant strains from Kuwait was tetracycline - trimethoprim/sulpha methoxazole - trimethoprim [TE-TMP/SMZ-TMP]. Saudi Arabian strains were of the same resistance pattern with additional resistance to ampicillin [AM] AM-TE-TMP/SMZ-TMP [34%] which was seem more often than TE-TMP/SMZ-TMP [26%]. Most of the strains [65%] from Bangladesh were sensitive to all the antimicrobial agents against which they were tested. Of the 8 strains which showed resistance, 50% were resistant to tetracycline alone. Study of carbohydrate fermentation of 12 sugars which were incubated for 21 days did not aid in discriminating different biotypes

Enterobacterias como agentes etiológicos de la diarrea en la comunidad / Enterobacteria as etiological agents of diarrhea in the community

Con el fin de identificar, a nivel de la comunidad, los entropatógenos bacterianos que producen diarrea en niños menores de 10 años, tomamos muestras de heces de 204 pacientes con cuadro diarreico de 1 a 7 días de evolución y de un grupo control, sin diarrea, conformado por 48 niños. Evaluamos también la recuperación de los microorganismos empleando o no medio Cary-Blair como medio de transporte e identificamos las categorías de Escherichia coli aisladas empleando pruebas biológicas e inmunológicas. Se destacaron como agentes etiológicos de la diarrea E. coli (58,8 por ciento), E. coli enterotoxigénica, productora de toxina labil (ECET-TL) (5,1 por ciento), Salmonella enteritidis (6,9 por ciento) y Shigella sonnei (5,9 por ciento). Cuando no se usó el medio de transporte de Cary-Blair la sensibilidad en la recuperación de los microorganismos fue del 37 por ciento. Se destaca la importancia de determinar la frecuencia real de las categorías del E. coli en nuestro medio