Caracterización de Escherichia coli D7111 productora de ß-LACTAMASA TEM-176 / Characterization of Escherichia coli D7111 producing the ß-LACTAMASA TEM-176

RESUMEN El presente reporte es la descripción original de bla TEM-176. Se caracterizaron los mecanismos de resistencia a antimicrobianos de un aislamiento de Escherichia coli enterotoxigénica, determinándose la resistencia a 22 antimicrobianos categorizados en 15 grupos diferentes mediante difusión en agar, estableciéndose grupo filogenético, mecanismos de resistencia y presencia de integrones de Clase 1 y 2 mediante PCR. Integrones y genes de resistencia a β-lactámicos fueron secuenciados. El aislamiento del grupo filogenético A, mostró resistencia o sensibilidad disminuida a ampicilina, amoxicilina más ácido clavulánico, ácido nalidíxico, ciprofloxacino, estreptomicina, kanamicina, tetraciclina, trimetoprim, sulfisoxazol, cotrimoxazol, azitromicina y nitrofurantoina, detectándose la presencia de bla TEM, aadA1/2, aphA1, sul3, tet(A) y un integron de Clase 2 conteniendo un gen dfrA1. La resistencia a quinolonas se relacionó con la substitución Ser83Ala. La secuencia de TEM mostró la substitución Ala222Val, la cual a la fecha no había sido descrita, reportándose como una nueva β-lactamasa, con el nombre de bla TEM-176.

ABSTRACT The present report is the original description of bla TEM-176. The mechanisms of resistance to antimicrobial agents were determined in an enterotoxigenic Escherichia coli, determining the susceptibility to 22 antimicrobials classified in 15 different groups by agar diffusion and establishing the phylogenetic group, mechanisms of resistance and presence of Class 1 and 2 integrons. Integrons and β-lactam resistance genes were sequenced. The isolate, belonging to phylogenetic group A, showed the presence of resistance or diminished susceptibility to a ampicillin, amoxicillin plus clavulanic acid, nalidíxic acid, ciprofloxacin, streptomycin, kanamycin, tetracycline, trimethoprim, sulfisoxazole, cotrimoxazole, azithromycin and nitrofurantoin, carrying bla TEM, aadA1/2, aphA1, sul3, tet(A) and a Class 2 integron containing a dfrA1 gene. Quinolone resistance was related to the substitution Ser83Ala. The TEM sequencing showed the presence of the new substitution Ala222Val, which led to the description of the new β-lactamase bla TEM-176.

Caracterización de Escherichia coli D7111 productora de ß-LACTAMASA TEM-176 / Characterization of Escherichia coli D7111 producing the ß-LACTAMASE TEM-176

RESUMEN El presente reporte es la descripción original de bla TEM-176. Se caracterizaron los mecanismos de resistencia a antimicrobianos de un aislamiento de Escherichia coli enterotoxigénica, determinándose la resistencia a 22 antimicrobianos categorizados en 15 grupos diferentes mediante difusión en agar, estableciéndose grupo filogenético, mecanismos de resistencia y presencia de integrones de Clase 1 y 2 mediante PCR. Integrones y genes de resistencia a β-lactámicos fueron secuenciados. El aislamiento del grupo filogenético A, mostró resistencia o sensibilidad disminuida a ampicilina, amoxicilina más ácido clavulánico, ácido nalidíxico, ciprofloxacino, estreptomicina, kanamicina, tetraciclina, trimetoprim, sulfisoxazol, cotrimoxazol, azitromicina y nitrofurantoina, detectándose la presencia de bla TEM, aadA1/2, aphA1, sul3, tet(A) y un integron de Clase 2 conteniendo un gen dfrA1. La resistencia a quinolonas se relacionó con la substitución Ser83Ala. La secuencia de TEM mostró la substitución Ala222Val, la cual a la fecha no había sido descrita, reportándose como una nueva β-lactamasa, con el nombre de bla TEM-176.

ABSTRACT The present report is the original description of bla TEM-176. The mechanisms of resistance to antimicrobial agents were determined in an enterotoxigenic Escherichia coli, determining the susceptibility to 22 antimicrobials classified in 15 different groups by agar diffusion and establishing the phylogenetic group, mechanisms of resistance and presence of Class 1 and 2 integrons. Integrons and β-lactam resistance genes were sequenced. The isolate, belonging to phylogenetic group A, showed the presence of resistance or diminished susceptibility to a ampicillin, amoxicillin plus clavulanic acid, nalidíxic acid, ciprofloxacin, streptomycin, kanamycin, tetracycline, trimethoprim, sulfisoxazole, cotrimoxazole, azithromycin and nitrofurantoin, carrying bla TEM, aadA1/2, aphA1, sul3, tet(A) and a Class 2 integron containing a dfrA1 gene. Quinolone resistance was related to the substitution Ser83Ala. The TEM sequencing showed the presence of the new substitution Ala222Val, which led to the description of the new β-lactamase bla TEM-176.

Escherichia coli enterotoxigénica y enteroagregativa: prevalencia, patogénesis y modelos múridos / Enterotoxigenic and enteroaggregative Escherichia coli: prevalence, pathogenesis and murine models

Resumen Los patotipos de Escherichia coli enterotoxigénica (ETEC) y enteroagregativa (EAEC) son importantes agentes etiológicos causantes de diarrea en niños menores de cinco años de México y países en desarrollo, en quienes causan numerosas muertes. Ambos se han asociado con retraso en el crecimiento infantil y son los principales agentes causales de la "diarrea del viajero". La patogénesis de ambas bacterias se inicia cuando estas se adhieren al epitelio intestinal mediante fimbrias, denominadas factores de colonización en las cepas ETEC aisladas de humano y fimbrias de adherencia agregativa en las cepas de EAEC. Una vez que ETEC se adhiere al enterocito produce una o ambas de sus toxinas e induce la secreción de iones de cloruro, sodio y agua al lumen intestinal, produciendo su característica diarrea acusa. EAEC se une al epitelio intestinal formando una biopelícula, induce la producción de moco, libera sus toxinas y promueve inflamación. Modelos de infección de EAEC y ETEC con ratones C57BL/6 silvestres y deficientes del ligando de CD40 (con microbiotas intactas), respectivamente, revelaron que la desnutrición y la dieta baja en cinc incrementan la infección de EAEC causando retraso en el crecimiento y que ETEC coloniza, persiste e induce respuesta inmune humoral local y sistémica.

Abstract Enterotoxigenic (ETEC) and enteroaggregative Escherichia coli (EAEC) pathotypes are important etiological agents causative of diarrhea in children younger than 5 years of age in Mexico and in developing countries, where they cause numerous deaths. Both have been associated with delayed growth in children and are the main causative agents of traveler's diarrhea. The pathogenesis of both bacteria starts by adhering to the intestinal epithelium by means of fimbriae, called colonization factors in human ETEC isolates and aggregative adherence fimbriae in EAEC isolates. Once ETEC adheres to the enterocyte, it produces one or both of its toxins and induces the secretion of chloride and sodium ions and water into the intestinal lumen, producing its characteristic watery diarrhea. EAEC binds to the intestinal epithelium forming a biofilm, induces the production of mucus, releases its toxins and promotes inflammation. EAEC and ETEC infection models with wild-type C57BL/6 and CD40 ligand-deficient mice (with intact microbiota), respectively, revealed that undernutrition and low-zinc diet increases EAEC infection, causing growth retardation, and that ETEC colonizes, persists and induces local and systemic humoral immune response.

Surveillance for enterotoxigenic & enteropathogenic Escherichia coli isolates from animal source foods in Northwest Iran

Background & objectives: Diarrhoeagenic Escherichia coli strains are common agents of diarrhoea particularly in developing countries. Food products of animal origin are considered as common carriers of E. coli. This study was undertaken to identify enterotoxigenic Escherichia coli (ETEC) and enteropathogenic E. coli (EPEC) pathotypes in animal-source foods (ASF). Methods: A total of 222 ASF samples were investigated. Based on the culture and biochemical tests, 109 E. coli isolates were identified. Duplex-polymerase chain reaction assay was used to detect ETEC and EPEC. The target genes selected for each category were the lt and st for the ETEC, and eae and bfp for the EPEC isolates. Results: The occurrence of E. coli in dairy and meat products was 45 and 52.5 per cent, respectively. Among the E. coli isolates, two ETEC, one typical EPEC and three atypical EPEC were detected in meat samples, whereas only one typical EPEC and one atypical EPEC were detected in dairy samples. Interpretation & conclusions: Our results showed presence of ETEC and EPEC strains in ASFs. The milk without pasteurization and traditional dairy products produced in unhygienic conditions are most likely the main sources of E. coli pathotypes and other zoonotic pathogens and thus can be considered a potential hazard to the health of the community.

Piglet colibacillosis diagnosis based on multiplex polymerase chain reaction and immunohistochemistry of paraffin-embedded tissues

Enterotoxigenic Escherichia coli (ETEC) causes diarrhea in pigs, referred to as colibacillosis. The aim of this study was to optimize multiplex polymerase chain reaction (PCR) and immunohistochemistry (IHC) analyses of paraffin-embedded material to detect pathogenic E. coli strains causing colibacillosis in pigs. Multiplex PCR was optimized for fimbriae (F18, F4, F6, F5, and F41) and toxins (types A and B heat-stable toxins [STaP and STb], heat-labile toxin [LT], and type 2 Shiga toxin [ST(x2e)]), and IHC was optimized for an anti-E. coli polyclonal antibody. Samples (132) from pigs received between 2006 and 2014 with clinical and histopathological diagnoses of colibacillosis were analyzed. E. coli was detected by IHC in 78.7%, and at least one virulence factor gene was detected in 71.2%. Pathogenic strains of ETEC with at least one fimbria and one toxin were detected in 40% of the samples in multiplex PCR. The most frequent virulence types were F18-STaP (7.5%), F18-STaP-STb (5.7%), and F4-STaP (3.8%). A statistically significant association was noted between virulence factors F4, F18, STaP, and STb and positive immunostaining results. Colibacillosis diagnosis through multiplex PCR and IHC of paraffin-embedded tissues is a practical approach, as samples can be fixed and stored for long periods before analysis.

Antimicrobial susceptibility profile of enterotoxigenic and enteropathogenic Escherichia coli isolates obtained from fecal specimens of children with acute diarrhea / Perfil de suscetibilidade a drogas antimicrobianas de amostras de Escherichia coli enterotoxigênica e enteropatogênica isoladas de espécimes fecais de crianças com doença diarreica aguda

ABSTRACT Among the diseases which etiopathogenesis is associated with Escherichia coli, acute diarrhea stands out. Studies on the characterization of the antimicrobial susceptibility profile contribute to the selection of appropriate empirical antimicrobial therapy. In this study, the antimicrobial susceptibility profile of 98 enterotoxigenic E. coli (ETEC) and enteropathogenic E. coli (EPEC) strains isolated from fecal specimens of children with acute diarrhea was evaluated. The resistance rates to ampicillin, sulfamethoxazole/trimethoprim, amoxicillin/clavulanate, and nalidixic acid were high, ranging from 34.7% to 10.2%. The result of this research recommends the use of cefotaxime and ceftriaxone for the empirical treatment of children with acute diarrhea which the etiology suggested is ETEC or EPEC.

RESUMO Entre as doenças cuja etiopatogenia está associada à Escherichia coli, destaca-se a doença diarreica aguda. Estudos que visam à caracterização do perfil de suscetibilidade antimicrobiana contribuem para o delineamento de antibioticoterapia empírica eficaz. Neste estudo, foi avaliado o perfil de suscetibilidade a antimicrobianos de 98 amostras de E. coli enterotoxigênica (ETEC) e E. coli enteropatogênica (EPEC) isoladas de crianças com doença diarreica. As frequências de resistência a ampicilina, sulfametoxazol-trimetoprima, amoxicilina-clavulanato e ácido nalidíxico foram elevadas, variando entre 34,7% e 10,2%. Esta pesquisa recomenda o emprego de cefotaxima e ceftriaxona para o tratamento empírico de crianças com quadro de diarreia cuja etiologia sugerida seja ETEC ou EPEC.

Construction of a live attenuated Salmonella strain expressing FanC protein to prevent bovine enterotoxigenic Escherichia coli and evaluation of its immunogenicity in mice

To construct a novel vaccine candidate against bovine enterotoxigenic Escherichia coli (ETEC), FanC, the major subunit of K99 fimbriae adhesion, was inserted into secretion plasmid pYA3560 containing a β-lactamase secretion system. This was then transformed into Δasd Δcrp Salmonella (S.) Typhimurium and designated as JOL950. Secretion of recombinant fanC fimbrial antigens was confirmed by immunoblot analysis. Groups of mice were inoculated with single or double doses of JOL950. Another group was used as a negative control. Compared to control mice, all immunized mice had significantly higher levels (p < 0.05) of serum immunoglobulin (Ig)G, and secretory IgA against FanC. The IgG2a and IgG1 titer assays revealed that immunization highly induced IgG2a compared to that of IgG1, indicating that T helper-1- related cell-mediated immune responses may be elicited by JOL950. The results show that both systemic and mucosal immunities against selected fimbrial antigens of bovine ETEC expressed by a live attenuated S. Typhimurium strain are prominently produced in mice immunized with JOL950 via an oral route.

Epidemiological Investigation on an Outbreak of Enterotoxigenic E. coli among the Baseball Club Students of High School in Ulsan City, 2014 / 農村醫學 地域保健

OBJECTIVES: An outbreak of food poisoning occurred among the baseball club students at a high school in Ulsan city in 2014. An epidemiological investigation was carried out to examine the infection source and the transmission route of pathogen, and to prevent a recurrence. METHODS: A questionnaire survey was conducted for 26 male students and 2 food handlers. Rectal swabs were examined in 7 students and the 2 food handlers, and an environmental investigation was performed. A retrospective cohort study was used to evaluate the association between risk factors and disease. RESULTS: The attack rate was 35.7% (10 persons/28 persons) from June 9 to 14, and Enterotoxigenic E. coli ST/LT was isolated from 7 among 28 persons. The study revealed that no food was a significant risk factor for the outbreak. There were no connection between environmental factors and the outbreak. CONCLUSIONS: The major risk factors for this outbreak were presumed to be the contaminated ice cube and ice making machines and eating ice cube from the machines. More strict personal and environmental hygiene need to be enforced to prevent such outbreaks.

The study of using siRNA technology to silence expression of LT gene of Enterotoxigenic Escherichia coli / 国际检验医学杂志

The distinctive LT siRNAs were designed according to the LT sequence .During the process of cultivation ,siRNA targeting the LT gene ,non‐specific control siRNA ,negative control siRNA and culture medium were added into siRNA group (siRNA‐LT1 group , siRNA‐LT2 group) ,siRNA‐coa3 group ,siRNA‐NC group and blank control group ,respectively ,and three times in each group (1 nmol each time) .After siRNA added at the first time ,bacteria was collected in 45 min (A) ,90 min (B) and 135 min (C) time points .The expression of mRNA in three time points (A ,B and C) were detected by real‐time fluorescence quantitative PCR .The protein level of LT in siRNA‐LT1 group ,siRNA‐LT2 group and blank control group were detected by Western blot in three time points .Results The results of real‐time fluorescence quantitative PCR showed that inhibition of siRNA‐LT1 on the expression of LT mRNA at the three time points(A ,B and C)were 70 .9% ,70 .1% ,72 .5% respectively ,and inhibition of siRNA‐LT2 on the ex‐pression of LT mRNA at the three time points(A ,B and C)were 70 .1% ,69 .2% and 70 .5% respectively .In the three time points (A ,B and C)the inhibition rate of the expression of LT mRNA in siRNA‐LT1 group and siRNA‐LT2 group were statistically lower than that in the siRNA‐NC group ,siRNA‐coa3 group and blank control group (P<0 .05) .The results of Western blot showed that in siRNA‐LT1 group the inhibitory rate of expression of LT protein in the three time points were 43 .1% ,18 .4% and 5 .0% ,re‐spectively ;in the siRNA‐LT2 group were 38 .2% ,15 .4% and 30 .1% ,respectively .Conclusion The specific siRNA could inhibit the expression of LT gene in vitro .

A CssA, CssB and LTB chimeric protein induces protection against Enterotoxigenic Escherichia coli

OBJECTIVES: Enterotoxigenic Escherichia coli (ETEC), a major cause of diarrhea in children under 5, is an important agent for traveler's diarrhea. Heat-labile enterotoxin (LT) and colonization factors (CFs) are two main virulence mechanisms in ETEC. CS6 is one of the most prevalent CFs consisting of two structural subunits viz., CssA, CssB, necessary for attachment to the intestinal cells. METHODS: In the present research, a chimeric trivalent protein composed of CssB, CssA and LTB was constructed. The chimeric gene was synthesized with codon bias of E. coli for enhanced expression of the protein. Recombinant proteins were expressed and purified. Mice were immunized with the recombinant protein. The antibody titer and specificity of the immune sera were analyzed by ELISA and Western blotting. Efficiency of the immune sera against ETEC was evaluated. RESULTS: Antibody induction was followed by immunization of mice with the chimeric protein. Pretreatment of the ETEC cells with immunized animal antisera remarkably decreased their adhesion to Caco-2 cells. DISCUSSION: The results indicate efficacy of the recombinant chimeric protein as an effective immunogen, which induces strong humoral response as well as protection against ETEC adherence and toxicity. .

A surveillance of enteropathogens in piglets from birth to seven days of age in Brazil / Levantamento dos enteropatógenos de leitões do nascimento a sete dias de idade no Brasil

The purpose of the study was to evaluate the real importance of anaerobic enteropathogens and rotavirus in contrast to more common agents as cause of diarrhea in piglets within the first week of life. Sixty 1- to 7-day-old piglets, 30 diarrheic and 30 non-diarrheic (control), from 15 different herds were selected, euthanized and necropsied. Samples of the jejunum, ileum, colon, cecum and feces were collected from the piglets and analyzed to determine the presence of the following enteropathogens: enterotoxigenic Escherichia coli (ETEC), Clostridium perfringens types A and C, Clostridium difficile, rotavirus and Isospora suis. Among diarrheic piglets, 23.3% were positive for C. difficile, 70% for C. perfringens type A cpb2+, 14.3% for rotavirus and 10% for ETEC. Among non-diarrheic control piglets, 10% were positive for C. difficile, 76.7% for C. perfringens type A cpb2+, 0% for rotavirus, 3.3% for ETEC and 3.3% for I. suis. C. perfringens type C was not detected in any of the animals. Histological lesions characteristic of C. difficile, E. coli and rotavirus were observed. However, no C. perfringens type A suggestive lesions were detected. There was a positive correlation between mesocolon edema and the presence of C. difficile toxins. Although C. perfringens type A cpb2+ was the most frequently detected enteropathogen, there was no association between its presence and diarrhea or macro or microscopic changes. C. difficile and Rotavirus were the most relevant pathogens involved with neonatal diarrhea in this study, and histopathology associated with microbiological test proved to be the key to reach a final diagnosis.

O objetivo do presente estudo foi avaliar a real importância de enteropatógenos anaeróbios e rotavirus em comparação à outros agentes mais comuns como causa de diarreia em leitões até cinco dias de idade. Leitões com 0 a 7 dias de vida, 30 diarreicos e 30 não diarreicos (controles) de 15 granjas diferentes foram eutanasiados e necropsiados. Amostras de jejuno, íleo, colon e ceco foram coletadas e submetidas à detecção dos seguintes enteropatógenos: Escherichia coli enterotoxigênica (ETEC), Clostridium perfringens, Clostridium difficile, rotavirus e Isospora suis. Entre os animais diarréicos, 23.3% foram positivos para C. difficile, 70% para C. perfringens tipo A cpb2+, 14.3% para rotavirus e 10% para ETEC. Entre os leitões não-diarréicos, 10% foram positivos para C. difficile, 76.7% para C. perfringens tipo A cpb2+, 3.3% para ETEC e 3.3% for I. suis. C. perfringens tipo C não foi detectado em nenhum animal. Lesões histológicas características de C. difficile, E. coli e rotavirus foram observadas. Por outro lado, nenhuma lesão sugestiva de C. perfringens foi detectada. Foi possível observar uma correlação positiva entre edema de mesocolon e presença das toxinas A/B. Apesar de C. perfringens tipo A cpb2+ ter sido o patógeno mais encontrado, nenhuma associação com lesões foi encontrada. C. difficile e Rotavirus foram os agentes mais relevantes associados à diarreia neonatal, e ficou demonstrada a relevância de associação de histopatologia com testes de detecção microbiológica para se firmar um diagnóstico.

Field evaluation of Enterotoxigenic Escherichia coli-specific bacteriophage (PhiCJ19) as a feed additive / 대한수의학회지

Field efficacy of enterotoxigenic Escherichia coli-specific phage (PhiCJ19) as a feed additive was evaluated in weaning piglets. Fifty-four piglets at 3~4 weeks old were allocated in three different groups and two of them were fed with bacteriophage at different concentrations (10(6) PFU/kg feed and 10(8) PFU/kg feed, respectively) for 30 days. Body weight and feed intake were measured at 10 days interval and body condition and fecal score were inspected every day. Based on the measurement, feed conversion rate (FCR) and average daily gain (ADG) of each group during 30 days were analyzed. The analysis suggests that the bacteriophage may help the improvement of FCR and ADG at 10(8) PFU/kg of bacteriophage feeding group in 30 days. A result from analysis of fecal score indicates that the bacteriophage also may help to relieve the intermittent diarrhea in post-weaning stage. Those results suggest that bacteriophage might help the growth of piglets in post-weaning stage.

Enterotoxins, colonization factors, serotypes and antimicrobial resistance of enterotoxigenic Escherichia coli (ETEC) strains isolated from hospitalized children with diarrhea in Bolivia

Enterotoxigenic Escherichia coli (ETEC) is recognized as the main cause of bacterial diarrhoea among children in Asia, Africa and Latin America but less investigated in Bolivia. OBJECTIVE: To determine the relation between enterotoxins, CFs and serotypes as well as the antimicrobial resistance patterns in a set of ETEC isolates collected from hospitalized children with acute diarrhea. In the present study we characterized 43 ETEC strains isolated from 2002 to 2006 from hospitalized children (0-5 years) with acute diarrhea in Bolivia. The strains were analyzed for heat-labile (LT) and heat-stable (ST) enterotoxins and colonization factor (CF) profiles, as well as for serogroups and antimicrobial resistance using phenotypic (ELISA, dot blot, slide agglutination and disc diffusion) and genotypic (Multiplex PCR) methods. Among the ETEC isolates tested, 30 were positive for LT, 3 for STh and 10 for LT/STh. Sixty-five percent (28/43) of the strains expressed one or more CF. The most common CFs were CS17 (n = 8) and CFA/I (n = 8). The phenotypical and genotypical results for toxins and CFs were congruent except for CS21 that was amplified in 10 of the strains by multiplex PCR, but CS21 pili was only detected phenotypically in four of these strains. The ETEC strains had diverse O and H antigens and the most common types were O8:H9 LT CS17 (n = 6; 14 percent) and O78:HNM LT-ST CFA/I (n = 4; 9 percent). The analysis of antibiotic resistance showed that 67 percent (n = 29/43) of the strains were resistant to one or several of the antimicrobial agents tested. Presence of CFs was associated with antibiotic resistance. CONCLUSION: The most common toxin profile was LT 70 percent, LT/STh 23 percent and STh 7 percent. High antimicrobial resistance to ampicillin among serogroups O6, O8 and O78 were the most common.

Clinical Characteristics and Etiology of Travelers' Diarrhea among Korean Travelers Visiting South-East Asia

The morbidity of travelers' diarrhea (TD) is still high. This study examined the incidence of common pathogens and characteristics of TD among Korean travelers who visited South-East Asian countries. We performed a prospective study involving 479 Korean travelers with diarrheal disease from February 2009 to April 2009 and stool samples were examined and questionnaire surveys were done after arrival. Enterotoxigenic Escherichia coli (ETEC) was found in 36.0% of TD cases, as were the following: Enteroaggregative Escherichia coli (EAEC) in 27.0%, Vibrio parahaemolyticus in 13.1%, and Norovirus in 11.5%. The detected rate of classic TD was higher in men (P = 0.007), in patients who had a shorter duration trip (P = 0.023) and in patients who drank more than 1 liter of water per day (P = 0.037). Positive stool culture rates were higher in men (P = 0.005), in hospitalized patients (P = 0.013). and in those who consumed impure water or raw foods (P = 0.033). A higher severity of disease corresponded to a significantly higher culture positivity rate (P = 0.029). We should consider the possibility of other pathogens in addition to ETEC in patients with TD who visit South-East Asia. Travelers need to educate about risk factors associated with TD.

Protective effects of a transgenic carrot vaccine on piglet diarrhea / 대한수의학회지

The study evaluated whether a transgenic carrot vaccine could induce a K88-specific immune response in sows and whether the resultant maternal antibody could protect piglets against enterotoxigenic Escherichia coli (ETEC) K88ac infection. Sows (n = 15) selected randomly from a farm in Korea were assigned to three groups (n = 5 per group: control [untreated]), group A (orally inoculated with a non-transgenic and transgenic carrot vaccines at 2 and 4 weeks ante partum, respectively), and group B (conventionally vaccinated according to the manufacturer's instructions). After 7 days of lactation, 5 piglets selected randomly from each group were challenged with 1 x 1010 colony forming units/mL ETEC K88ac. Group C had the lowest mean fecal consistency score on post-challenge days 1 and 7. Histiologically, On post-challenge day 7, group C showed an increased duodenum and ileum villus:crypt ratio, compared to group A in the duodenum, with group B displaying the highest ratio. Groups B and C had more increased villus width than group A in the jejunum. Group C displayed the greatest increase in villus width in the ileum. The colostrums and serum from groups B and C displayed higher concentrations of IgA and IgG against ETEC K88, compared to group A. Based on the results, it was concluded that the transgenic carrot vaccine in sow per oral may have an effect on preventing piglet diarrhea as good as commercial recombinant vaccine.

Effect of stress on production of heat labile enterotoxin by Escherichia coli.

Enterotoxigenic Escherichia coli (ETEC) is an important pathogen responsible for secretory diarrhoea. The production of heat labile enterotoxin (LT), by ETEC, is largely responsible for the pathogenesis of diarrhoea. In the present study we investigated the effect of stress factors such as temperature, pH, osmotic stress and nutritional limitation on the production of LT by ETEC using in-house GMI-ELISA. Four strains of E. coli consisting, one standard strain MTCC 723 and three clinical isolates were used in the study. Maximum amount of LT (OD 3.285) was produced at 37 0 C followed by 40 0 C (OD 3.305). Growth of E. coli in medium with pH 8.6 resulted in maximum amount of LT production (OD 3.489). LT was not detectable when bacteria were grown in medium with pH ≤7.2 and ≥ 9.2. Sodium chloride concentration of 0.2 M stimulated maximum amount of LT production. Maximum amount of LT was produced when the bacteria were grown in medium containing 2.5g/l of glucose. All the stress factors had a significant effect on the LT production by E. coli , though quantitative differences in the various strains were observed.

Estudio de correlación entre cepas Escherichia coli sorbosa negativa y su capacidad de producir enterotoxinas / Study of correlation between negative sorbose E. coli strains and their enterotoxin-producing capacity

Se estudiaron 50 cepas de Escherichia coli sorbosa negativas, aisladas de niños con diarreas líquidas de aparición espontánea. La identificación hasta especie se realizó por métodos convencionales, incluidos los marcadores fenotípicos sorbosa y sorbitol. Las técnicas de reacción en cadena de la polimerasa e hibridación de ADN, fueron realizadas para confirmar la capacidad de producción de enterotoxinas. Se obtuvo muy buena correlación entre las cepas de Escherichia coli sorbosa negativas y su capacidad de elaborar enterotoxinas termolábil y termoestable. El estudio demostró un alto porcentaje de estas cepas con fragmentos de genes codificadores, 94 y 44 % respectivamente, predominando la enterotoxina termoestable. Se obtuvieron los principales biotipos primarios de importancia taxonómica y epidemiológica. Se demostró que el método de la sorbosa posee cualidades que lo distinguen como marcador fenotípico, con 100 % de sensibilidad y 88 % de especificidad, revelándose como método de diagnóstico presuntivo práctico y de gran utilidad para los Laboratorios de Microbiología Clínica.

Fifty negative sorbose Escherichia coli strains isolated from children who suffered spontaneously occurring fluid diarrheas were studied. Identification up to the level of species was performed by conventional methods including phenotypical markers known as sorbose and sorbitol. The PCR and DNA gene hybridization were applied to confirm the enterotoxin-producing capacity. A good correlation between negative sorbose Escherichia coli and their capacity of producing heat-labile and heat -stable enterotoxin was observed. The study showed a high percentage of these strains with encoding gene fragments, 94 and 44% respectively, being heat-stable enterotoxin the predominant. The main primary biotypes of taxonomic and epidemiological importance were obtained. It was demonstrated that the sorbose method has certain qualities that make it stand out as a phenotypical marker, with 100% sensitivity and 88% specificity, and as a practical presumptive diagnostic method that is very useful for Clinical Microbiology Laboratories.

Sorogrupos de Escherichia coli enterotoxigênica isolada de coproculturas, no período de 1983 a 1987, no município de São Paulo / Enterotoxigenic Escherichia coli serogroups in isolates from stool cultures made from 1983 to 1987 in the municipality of Säo Paulo, Brazil

Durante o quinquênio 1983-1987 foram isoladas, na Seção de Bacteriologia do Instituto Adolfo Lutz, 87 cepas de Escherichia coli enterotoxigênica, a partir 5629 coproculturas. A média percentual de positividade nestes 5 anos foi de 1,54%. Entre as 87 cepas produtoras de toxina termoestável, 31(35,63%) produziram também toxina termolábil, com relação ao antígeno fator de colonização I e II (antígeno fimbriado F2 e F3), 43 (49,43%) cepas apresentaram um desses fatores. A utilização de 33 soros somáticos permitiu a identificação sorológica de 61 (70,11%) das 87 cepas estudadas. Os sorogrupos 0:6, 0:153, 0:78, 0:27 e 0:139 foram os mais frequentes (AU).

Competitive inhibition of adherence of ETEC and EPEC to intestinal epithelial cells by purified adhesin of bifidobacterium adolescentis 1027 / 解放军医学杂志

Objective To observe competitive inhibition of adherence of enterotoxigenic Escherichia coli (ETEC) and enteropathogenic Escherichia coli (EPEC) to intestinal epithelial cells by purified adhesin derived from bifidobacterium adolescentis 1027. Methods The number of bacteria adherent to intestinal epithelial cell line Lovo was counted and the results were analyzed by comparison. Results The purified adhesin in the concentration of 10?g/ml, 20?g/ml and 30?g/ml could significantly inhibit the adhesion of ETEC and EPEC to intestinal epithelial cell line Lovo. The higher the concentration of adhesin the higher inhibition rate was observed. Concentrations lower than 10?g/ml had no such effect. Conclusion The purified adhesin of bifidobacterium adolescentis 1027 could inhibit the adhesion of ETEC and EPEC to intestinal epithelial cell line Lovo, and the effect was dose-dependent.