Pathogenic detection and molecular tracing of a bacillary dysentery outbreak by Shigella sonnei in Huainan city / 中华预防医学杂志

Objective: To understand the virulence gene and drug resistance profile of Shigella sonnei outbreak in Huainan city, and conduct pathogenic traceability analysis. Methods: Water samples and feces related to an infectious diarrhea outbreak in Huainan city in August 2020 were collected for multiple pathogen detection. Virulence gene, drug sensitivity, pulse-field gel electrophoresis and whole genome sequencing of Shigella isolates were analyzed respectively. Results: 38 strains of Shigella sonnei were detected in 56 samples of mucilage feces with a positive rate 67.86%, and all serotypes were Shigella sonnei Phase I. Three strains of Shigella sonnei were detected by fluorescence PCR in the Gram-negative (GN) bacterial enrichment solution of terminal water and well water. Virulence genes were ipaH positive (38), ipaH/ial (31) and ipaH/ial/sen positive (1), respectively. The drug resistance spectrum showed that 9 of 14 antibiotics were 100% resistant, and only imipenem, chloramphenicol, ceftazidime and ciprofloxacin were effective drugs. XbaⅠ restriction enzyme map type of 36 isolates was completely consistent, and the ST type analysis of 3 strains was ST152. Whole genome sequencing and analysis verified that the outbreak was caused by a single clonal group of strains, and revealed that the isolates of the outbreak were clustered into a large cluster with 3 Chinese strains and 1 Korean strain in the database, far away from the strains of other countries. Conclusion: The outbreak is caused by a single clone of Shigella sonnei, which are low virulence strains and have multiple drug resistance.

Anti-Bacterial Effect of Lactobacillus rhamnosus Cell-Free Supernatant Possessing Lysozyme Activity Against Pathogenic Bacteria

Recently, there has been a growing demand for natural preservatives because of increased consumer interest in health. In this study, we produced Lactobacillus rhamnosus cell-free supernatant (LCFS) and evaluated and compared its antimicrobial activity with existing natural preservatives against pathogenic microorganisms and in chicken breast meat contaminated with Escherichia coli and Staphylococcus aureus. Lactobacillus rhamnosus cell-free supernatant possessed 30 units of lysozyme activity and contained 18,835 mg/L of lactic acid, 2,051 mg/L of citric acid and 5,060 mg/L of acetic acid. Additionally, LCFS inhibited the growth of fourteen pathogenic bacteria, S. aureus, Bacillus cereus, Listeria monocytogenes, Vibrio parahaemolyticus, Listeria innocua, S. epidermidis, L. ivanovii, E. coli, Pseudomonas aeruginosa, Shigella sonnei, Shi. flexneri, Proteus vulgaris, Pseudomonas fluorescens, and Klebsiella pneumoniae. The antibacterial activity of LCFS was stronger than that of egg white lysozyme (EWL), Durafresh (DF) and grapefruit seed extract (GSE). Additionally, LCFS maintained its antimicrobial activity after heat treatment at 50℃~95℃ and at pH values of 3~9. Moreover, LCFS inhibited the growth of E. coli and S. aureus in chicken breast meat. In conclusion, it is expected that LCFS, which contains both lysozyme and three organic acids, will be useful as a good natural preservative in the food industry.

Long-term Clinical Course of Post-infectious Irritable Bowel Syndrome After Shigellosis: A 10-year Follow-up Study

BACKGROUND/AIMS: A limited number of studies are available regarding the long-term natural history of post-infectious irritable bowel syndrome (PI-IBS). We aimed to investigate the long-term clinical course of PI-IBS. METHODS: A prospective cohort study was conducted from a 2001 shigellosis outbreak in a Korean hospital with about 2000 employees. A cohort of 124 hospital employees who were infected by Shigella sonnei due to contaminated food in the cafeteria, and 105 sex- and age-matched, non-infected, controls were serially followed for their bowel symptoms by questionnaire surveys for 10 years. RESULTS: The Shigella-infected cohort showed significantly higher odds ratio for irritable bowel syndrome (IBS) at 1-year (11.90; 95% CI, 1.49-95.58) and 3-year (3.93; 95% CI, 1.20-12.86) follow-up, compared to their controls. However, corresponding odds ratio for PI-IBS was not significantly increased at 5-year (1.88; 95% CI, 0.64-5.54) and 8-year (1.87; 95% CI, 0.62-5.19) follow-up. At 10-year follow-up survey, the prevalence of IBS was similar for the Shigella-infected cohort and their controls (23.3% versus 19.7%, P = 0.703). Risk factors which were independently associated with PI-IBS among the Shigella-infected cohort included younger age, previous history of functional bowel disorder, and longer duration of diarrhea at baseline. CONCLUSIONS: Patients who were infected by Shigella sonnei experienced significantly increased risk of IBS until 3 years after shigellosis, and modestly increased risk until 8 years, but showed similar risk of IBS with uninfected controls at 10 years post-infection. PI-IBS is quite a chronic disorder, and follows a long-term natural course.

Infection of Extended-Spectrum β-Lactamase Producing Shigella flexneri in Children Attending a Childcare Center in Korea

Shigella is a common cause of bacterial enteritis worldwide. Shigella sonnei accounts for 90% of Shigella infections and Shigella flexneri is rarely reported in Korea. Although the incidence of Shigella infection has decreased, the incidence of organisms with antibiotic resistance has gradually increased in Korea. An outbreak of extended-spectrum β-lactamase (ESBL)-producing S. sonnei in children was reported in Korea; however, ESBL-producing S. flexneri has not yet been reported. We report the first two cases of multidrug-resistant CTX-M-14-producing S. flexneri infections in Korean children.

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.

Shigella sonnei: ¨Est ocurriendo un cambio en nuestro medio? / Shigella sonnei: is a change occurring in our middle?

Objetivos: Determinar los serogrupos de Shigella como agentes etiol¢gicos de diarrea. Dise¤o: Estudio descriptivo, retrospectivo, anal¡tico. Instituci¢n: Instituto de Medicina Tropical, Universidad Nacional Mayor de San Marcos, Lima, Per£, y Hospital Nacional Daniel A. Carri¢n, Callao, Per£. Material biol¢gico : Aislamientos de Shigella sp. en coprocultivos. Intervenciones: Se revis¢ los aislamientos de Shigella sp. en coprocultivos, durante los a¤os 2010 y 2011, en la base de datos WHONET 5.6 del hospital, tanto de pacientes adultos como pedi tricos, ambulatorios, hospitalizados y atendidos en emergencia. Se distribuy¢ la Shigella por serogrupos. Principales medidas de resultados : Frecuencia absoluta y frecuencia relativa de Shigella sp. Resultados: El a¤o 2010 se aisl¢ 64 Shigellas sp.; 41 correspondieron al serogrupo flexneri (64,1 por ciento) y 20 al serogrupo sonnei (31,3 por ciento). En el a¤o 2011 se aisl¢ 90 Shigellas sp.; 36 correspondieron a serogrupo flexneri (40 por ciento) y 50 al serogrupo sonnei (55,6 por ciento). Las diferencias encontradas son estad¡sticamente significativas. Conclusiones: Shigella sonnei fue el serogrupo predominante en nuestro hospital.

Objectives: To determine Shigella serogroups as diarrhea etiological agents. Design: Descriptive, retrospective, analytical study. Setting: Instituto de Medicina Tropical, Universidad Nacional Mayor de San Marcos, Lima, Peru, and Hospital Nacional Daniel A. Carrion, Callao, Peru. Biologic material: Shigella sp. isolates in coprocultures. Interventions: Shigella sp. isolates in coprocultures of outpatient, hospitalized and emergency adult and pediatric patients attended during years 2010 and 2011were reviewed at the hospital WHONET 5.6 database. Shigella were distributed by serogroups. Main outcome measures : Absolute and relative frequency of Shigella sp. Results: Sisty-four Shigellas sp were isolated in 2010; 41 corresponded to flexneri serogroup (64.1 per cent) and 20 to sonnei serogroup (31.3 per cent). Ninety Shigellas sp. were isolated in 2011; 36 corresponded to flexneri serogroup (40 per cent) and 50 to sonnei serogroup (55,6 per cent). Differences were statistically significant. Conclusions: Shigella sonnei was the predominant serogroup at our hospital.

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.

Antagonistic activity expressed by Shigella sonnei: identification of a putative new bacteriocin

Bacteriocins are antibacterial, proteinaceous substances that mediate microbial dynamics. Bacteriocin production is a highly disseminated property among all major lineages of bacteria, including Shigella. In this paper, we addressed the purification and characterisation of a bacteriocin produced by a Shigella sonnei strain (SS9) isolated from a child with acute diarrhoea. The substance was purified through ammonium-sulphate precipitation and sequential steps of chromatography. The intracellular fraction obtained at 75% ammonium sulphate maintained activity following exposure to pH values from 1-11 and storage at -80ºC for more than two years and was inactivated by high temperatures and proteases. The molecular mass of the purified bacteriocin was determined by mass spectrometry to be 18.56 kDa. The N-terminal sequence of the bacteriocin did not match any other antibacterial proteins described. A putative new bacteriocin produced by S. sonnei has been detected. This bacteriocin may represent a newly described protein or a previously described protein with a newly detected function. Considering that SS9 expresses antagonism against other diarrhoeagenic bacteria, the bacteriocin may contribute to S. sonnei virulence and is potentially applicable to either preventing or controlling diarrhoeal disease.

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.

Surveillance of Antimicrobial Susceptibility Patterns among Shigella Species Isolated in China during the 7-Year Period of 2005-2011

BACKGROUND: Shigella is a frequent cause of bacterial dysentery in the developing world. Treatment with antibiotics is recommended for shigellosis, but the options are limited due to globally emerging resistance. This study was conducted to determine the frequency and pattern of antimicrobial susceptibility of Shigella in China. METHODS: We studied the antimicrobial resistance profiles of 308 Shigella spp. strains (260 S. flexneri, 40 S. sonnei, 5 S. boydii, and 3 S. dysenteriae) isolated from fecal samples of patients (age, from 3 months to 92 yr) presenting with diarrhea in different districts of Anhui, China. The antimicrobial resistance of strains was determined by the agar dilution method according to the CSLI guidelines. RESULTS: The most common serogroup in the Shigella isolates was S. flexneri (n=260, 84.4%), followed by S. sonnei (n=40, 13.0%). The highest resistance rate was found for nalidixic acid (96.4%), followed by ampicillin (93.2%), tetracycline (90.9%), and trimethoprim/sulfamethoxazole (80.8%). Among the isolates tested, 280 (91.0%) were multidrug resistant (resistant to > or =2 agents). The most common resistance pattern was the combination of ampicillin, tetracycline, and trimethoprim/sulfamethoxazole (70.8%). Resistance to ampicillin and tetracycline were more common among S. flexneri than among S. sonnei isolates. CONCLUSIONS: S. flexneri is predominant in Anhui, China, and its higher antimicrobial resistance rate compared with that of S. sonnei is a cause for concern. Continuous monitoring of resistance patterns is necessary to control the spread of resistance in Shigella. The recommendations for antimicrobial treatment must be updated regularly based on surveillance results.

CTX-M-55-Type Extended-Spectrum beta-lactamase-Producing Shigella sonnei Isolated from a Korean Patient Who Had Travelled to China

We report a case of CTX-M-55-type extended-spectrum beta-lactamase (ESBL)-producing Shigella sonnei infection in a 27-year-old Korean woman who had traveled to China. The patient was admitted to the hospital due to abdominal pain, watery diarrhea, and fever (39.3degrees C). S. sonnei was isolated from her stool specimens, and the pathogen was found to be resistant to cefotaxime due to CTX-M-55-type ESBL. Insertion sequence (IS)Ecp1 was found upstream of the blaCTX-M-55 gene. The blaCTX-M-55 gene was transferred from the S. sonnei isolate to an Escherichia coli J53 recipient by conjugation. Pulsed-field gel electrophoresis and Southern blotting revealed that the blaCTX-M-55 gene was located on a plasmid of approximately 130 kb.

Diarreia associada a Shigella em crianças e sensibilidade a antimicrobianos / Diarrhea associated with Shigella in children and susceptibility to antimicrobials

OBJETIVO: Avaliar a distribuição e suscetibilidade a antimicrobianos de Shigella isolada de crianças com diarreia aguda e sem diarreia em Teresina (PI). MÉTODOS: Quatrocentas crianças com idade até 60 meses foram estudadas. Fezes foram coletadas de todos os pacientes entre janeiro de 2004 e agosto de 2007. Shigella foi identificada por métodos convencionais e antibiograma e pesquisa de β-lactamase de espectro ampliado (ESBL) foram realizados por difusão em ágar. RESULTADOS: Shigelose foi detectada apenas em crianças com diarreia aguda (26/250; 10,4%), especialmente naquelas entre 6 e 24 meses de idade e nos meses chuvosos. Shigella foi suscetível a ceftriaxona, ciprofloxacina e ácido nalidíxico. Mais da metade das amostras foram resistentes a sulfametoxazol-trimetoprim e ampicilina. ESBL não foi detectada. CONCLUSÕES: S. flexneri é comum em Teresina. A resistência a ampicilina e sulfametoxazol-trimetoprim é preocupante, pois estas drogas são amplamente utilizadas na prática e sulfametoxazol-trimetoprim ainda é recomendada para tratamento de crianças com suspeita de shigelose.

OBJECTIVE: To evaluate the distribution and susceptibility to antimicrobials of Shigella isolated from children with acute diarrhea and without diarrhea in Teresina, state of Piauí, Brazil. METHODS: Four hundred children aged up to 60 months were studied. Stools were collected from all the patients between January 2004 and August 2007. Shigella was identified by conventional methods and antibiogram and extended-spectrum β-lactamase (ESBL) were performed by agar diffusion. RESULTS: Shigellosis was only detected in children with acute diarrhea (26/250; 10.4%), especially in those aged from 6 to 24 months and in the rainy months. Shigella was susceptible to ceftriaxone, ciprofloxacin and nalidixic acid. More than half of the strains were resistant to sulphametoxazole-trimethoprim and ampicillin. ESBL was not detected. CONCLUSIONS: S. flexneri is common in Teresina. The resistance to ampicillin and sulphametoxazole-trimethoprim gives cause for concern, as these drugs are widely used in practice and sulphametoxazole-trimethoprim is also recommended for treating children suspected of having shigellosis.

[ 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

Occurrence of class 2 integrons among multi-drug resistant Shigella sonnei isolated from Tehran, Iran in 2005

Shigellosis is one of the major causes of morbidity in children with diarrhea in Iran. Integrons play an important role in the evolution and dissemination of multidrug resistance in gram-negative bacteria. The occurrence of integrons among Shigella spp. is frequently reported throughout the world. The aim of this study was to assess the occurrence of class 2 integrons among the multi drug resistant S. sonnei isolated from Iranian children in 2005. The study was conducted in two major pediatric hospitals in Tehran, Iran. Fecal specimens and rectal swab collected from patients were cultured and identified as Shigella by the conventional methods. Antimicrobial susceptibility test was performed according to the standard CLSI guideline. Multi-drug resistant isolates of S. sonnei were further examined for the presence of class 2 integron by PCR using specific primers. Amplicons were confirmed by restriction endonuclease analysis. A total of 83 multi-drug resistant S. sonnei strains were isolated. Of these, 45 [54%] exhibited a class 2 integron of 2.1 kbp, and 34 [41%] a class 2 integron of 1.3 kbp. Class 2 integrons were not detected in four isolates. The results showed an increased occurrence of class 2 integron carrying S. sonnei isolated from children in Tehran in 2005

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

An Epidemiological Investigation on an Outbreak of Shigellosis in a Special School for Handicapped in Yeongcheon-si and in a Rehabilitation Facility in Gyeongsan-si, Korea, 2008 / 農村醫學 地域保健

OBJECTIVES: In September 2008, an outbreak of diarrhea occurred among students attending Y school in Yeongcheon-si. Shigella sonnei was cultured from some of the rectal swabs. An epidemiological investigation was carried out to determine the source of the infection and the mode of transmission of the shigellosis outbreak. METHODS: The index case lived in the D rehabilitation facility in Gyeongsan-si and an additional epidemiological investigation was carried out there. The cases could not be questioned due to their mental handicaps. The teachers were interviewed instead. A patient case was defined as a resident with diarrhea more than one time a day from September 18 to September 26, 2008 or a resident with confirmed Shigella sonnei at the Y school or the D rehabilitation facility. RESULTS: The attack rate was 1.2% (8 persons) among 659 persons in the Y school and D rehabilitation facility. Five persons were microbiologically confirmed to have the infection and three persons were diagnosed on the basis of symptoms. Shigella sonnei was cultured from five of the 659 rectal swabs. However, 80 environmental specimens including drinking water, preserved foods, and cooking utensils were negative. All eight patients were Y school students and had been living in group boarding and lodging. Six of them lived in the D rehabilitation facility and two lived in the dormitory at the Y school. Five cases showed pulsed-field gel electrophoresis patterns that were identical for Shigella sonnei. CONCLUSIONS: The results of this study showed that the infection source of the shigellosis outbreak, in the two places, were identical. It is likely that the infections initially spread from a teacher or volunteer and then among the students.