Effectiveness of aqueous and hydroalcoholic extracts of Acanthospermum australe (Loefl) Kuntze against diarrhea-inducing bacteria / Eficácia de extratos aquosos e hidroalcoólicos de Acanthospermum australe (Loefl) Kuntze contra bactérias indutoras de diarreia

Abstract Leaves and roots of Acanthospermum australe (Asteraceae) have been used in Brazilian folk medicine for the treatment of various ailments including diarrhea, skin diseases, blennorrhagia, dyspepsia, parasitic worms and malaria. The aim of study was to characterize the chemical profiles of the aqueous and hydroalcoholic extracts of leaves and roots of A. australe, and to evaluate their antimicrobial activities against diarrhea-inducing bacteria (Enterococcus faecalis, Shigella dysenteriae and Yersinia enterocolitica), as well as their cytotoxic properties. Aqueous leaf extracts were obtained by infusion, while aqueous root extracts were obtained by decoction. The hydroalcoholic leaf and root extracts were prepared by maceration in 90% ethanol for 3 days. Antimicrobial activity was assessed using standard techniques and cytotoxicity was evaluated using Chinese hamster ovary cells CHO-K1. Chemical analysis revealed the presence of tannins, flavonoids, saponins and phenolic compounds in the extracts. Although root extracts were not effective against E. faecalis, leaf extracts at concentrations of 20 mg/mL exhibited bactericidal activities against this microorganism. The hydroalcoholic root extract was unique in presenting a bactericidal effect against S. dysenteriae. None of the extracts showed bacteriostatic or bactericidal activities against Y. enterocolitica. The results presented herein demonstrate that the Gram-positive E. faecalis and the Gram-negative S. dysenteriae were susceptible to A. australe extracts, although bacteriostatic/bactericidal activities were only observed at concentrations considered too high for clinical application. Our results support the ethnopharmacological use of A. australe in the treatment of gastrointestinal disorders, particularly diarrhea caused by infectious bacteria, although further studies are required to determine the anti-diarrhea effects and the toxicities of the extracts in vivo.

Resumo Folhas e raízes de Acanthospermum australe (Asteraceae) têm sido usadas na medicina popular brasileira para o tratamento de várias doenças, incluindo diarreia, doenças de pele, blenorragia, dispepsia, vermes parasitas e malária. O objetivo deste estudo foi caracterizar os perfis químicos dos extratos aquosos e hidroalcoólicos das raízes e folhas de A. australe, e avaliar as suas atividades antimicrobianas contra as bactérias indutoras de diarreia (Enterococcus faecalis, Shigella dysenteriae e Yersinia enterocolitica), bem como sua citotoxicidade. Os extratos aquosos de folhas foram obtidos por infusão, enquanto que os extratos aquosos de raízes foram obtidos por decocção. Os extratos hidroalcoólicos de folhas e raízes foram preparados por maceração em etanol a 90% durante 3 dias. A atividade antimicrobiana foi avaliada utilizando técnicas padrão e a citotoxicidade foi avaliada utilizando células de ovário de hamster chinês CHO-K1. A análise química revelou a presença de taninos, flavonóides, saponinas e compostos fenólicos nos extratos. Apesar de extratos de raiz não foram eficazes contra E. faecalis, extratos de folhas em concentrações de 20 mg/mL apresentaram atividades bactericidas contra este microrganismo. O extrato hidroalcoólico de raiz foi o único a apresentar um efeito bactericida contra S. dysenteriae. Nenhum dos extratos apresentaram atividades bacteriostáticas ou bactericidas contra Y. enterocolitica. Os resultados apresentados demonstram que a bactéria Gram-positiva E. faecalis e a Gram-negativa S. dysenteriae foram suscetíveis aos extratos de A. australe, embora as atividades bacteriostáticos/bactericidas tenham sido apenas observados em concentrações consideradas elevadas para aplicação clínica. Os nossos resultados apoiam a utilização de etnofarmacológica de A. australe no tratamento de perturbações gastrointestinais, especialmente diarreia causadas por bactérias infecciosas, embora sejam necessários mais estudos para determinar os efeitos anti-diarreia e as toxicidades dos extratos in vivo.

Detection of E. coli O157:H7 and Shigella dysenteriae toxins in clinical samples by PCR-ELISA

Shiga toxin producing bacteria are potential causes of serious human disease such as hemorrhagic colitis, severe inflammations of ileocolonic regions of gastrointestinal tract, thrombocytopenia, septicemia, malignant disorders in urinary ducts, hemolytic uremic syndrome (HUS) Shiga toxin 1 (stx1), shiga toxin 2 (stx2), or a combination of both are responsible for most clinical symptoms of these diseases. A lot of methods have been developed so far to detect shiga toxins such as cell culture, ELISA, and RFPLA, but due to high costs and labor time in addition to low sensitivity, they have not received much attention. In this study, PCR-ELISA method was used to detect genes encoding shiga toxins 1 and 2 (stx1 and stx2). To detect stx1 and stx2 genes, two primer pairs were designed for Multiplex-PCR then PCR-ELISA. PCR products (490 and 275, respectively) were subsequently verified by sequencing. Sensitivity and specificity of PCR-ELISA method were determined by using genome serial dilution and Enterobacteria strains. PCR-ELISA method used in this study proved to be a rapid and precise approach to detect different types of shiga toxins and can be used to detect bacterial genes encoding shiga toxins.

Excretion product of shigella dysenteriae (sdyep) induced cell death in early larval stage of zebrafish (danio rerio): acridine orange and ethidium bromide (AO/EB) in vivo staining / Producto de excreción de shigella dysenteriae (pesdy) induce muerte celular en larvas de pez cebra (danio rerio): marcaje in vivo con naranja de acridina y bromuro de etidio (NA/BE)

In the field of studies of acute toxicity induced by bacterial agents, Shiga toxins have been relevant due to the severity of the extra-intestinal diseases they cause. Numerous studies have shown that Shiga toxin induced apoptosis in different cell types; however, this important process has been little studied in vivo experimental models. In this study, the effects of excretion products of Shigella dysenteriae, in which Shiga toxin is present, were investigated on early larval stages of Zebrafish, an animal model with many advantages over other in vivo experimental models traditionally used. Both the collection of eggs and larvae of Zebrafish, and the product from excretion from Shigella dysenteriae (SdyEP) were performed according to laboratory standards. Also, toxicity bioassay, larvae treatment with pure and diluted solution, 10-1, 10-2, 10-3 , 10-4 and 10-5, v/v SdyEP and cell death in vivo using Acridine Orange (AO) and Ethidium Bromide (EB) were applied. The excretion product of Shigella dysenteriae (SdyEP) effect was expressed in terms of larval mortality and dependent dilution rather than incubation time. The larval population surviving treatment with Shigella excretion product presents severe morphological effects. The larval population generally presents notable severe morphological damage, the necrosis state is represented by the opacity of the larvae after being treated for 24 h (b) compared to control. Other changes associated with larval anatomy were also observed; particularly the caudal end curvature was significant into 10%. The use of AO/EB revealed a distribution pattern from fluorescence into green and orange in surviving larvae SdyEP poisoning, there was a large population of dead cells around the anal and caudal region as evidenced by the presence of orange nuclei in greater numbers as controls in the larvae. The results support the application of coloring AO/EB in Zebrafish experimental models for the evaluation of the toxic action of new molecules and new products with therapeutic potential.

En el campo de los estudios de toxicidad aguda inducida por agentes bacterianos, las toxinas Shiga resultan relevantes debido a la severidad de las enfermedades extra-intestinales que causan. Numerosos estudios han demostrado que la toxina Shiga induce la apoptosis en diferentes tipos de células, sin embargo, este importante proceso ha sido poco estudiado en modelos experimentales in vivo. En este estudio, fueron evaluados los efectos del productos de excreción de Shigella dysenteriae (PESdy), sobre estadios larvarios de pez cebra (Danio rerio), un modelo animal con muchas ventajas sobre otros modelos experimentales in vivo utilizados tradicionalmente. Tanto la recolección de los huevos y larvas de pez cebra, así como la obtención del producto de la excreción, se realizaron de acuerdo a los estándares de laboratorio. Poblaciones larvarias, fueron tratadas con distintas soluciones; pura y diluidas, 101, 10-2, 10-3, 10-4 y 10-5, v/v de PESdy. La muerte celular in vivo, usando naranja de acridina (NA) y bromuro de etidio (BE) fue evaluada. El efecto del SdyEP, se expresó como dependiente de la concentracion y del tiempo de exposición. La población de larvas sobrevivientes, presentaron curvatura troncal en un 10%, en relación a los controles. La necrosis se puso en evidencia a través de la opacidad de las larvas después de 24 h. El uso de NA/BE reveló un patrón de distribución de la fluorescencia en verde y naranja en larvas sobrevivientes al tratamiento. Una granpoblación de células muertas, alrededor de la región anal y caudal, se ponen en evidencia por la presencia de núcleos de naranja en mayor número que en los controles. Los resultados apoyan la aplicación de la coloración NA/BE en modelo experimental de pez cebra, para la evaluación de la acción tóxica de nuevas moléculas y nuevos productos de excreción bacterial con potencial terapéutico.

Excretion product of shigella dysenteriae (sdyep) induced cell death in early larval stage of zebrafish (danio rerio): acridine orange and ethidium bromide (ao/eb) in vivo staining / El producto de excreción de la shigella dysenteriae (pesdy) Induce muerte celular en larvas de pez cebra (danio rerio): marcaje in vivo con naranja de acridina y bromuro de etidio (na/be)

In the field of studies of acute toxicity induced by bacterial agents, Shiga toxins have been relevant due to the severity of the extra-intestinal diseases they cause. Numerous studies have shown that Shiga toxin induced apoptosis in different cell types; however, this important process has been little studied in vivo experimental models. In this study, the effects of excretion products of Shigella dysenteriae, in which Shiga toxin is present, we investigated on early larval stages of Zebrafish, an animal model with many advantages over other in vivo experimental models traditionally used. Both the collection of eggs and larvae of Zebrafish, and the product from excretion from Shigella dysenteriae (SdyEP) were performed according to laboratory standards. Also, toxicity bioassay, larvae treatment with pure and diluted solution, 10-1, 10-2, 10-3 , 10-4 and 10-5 v/v SdyEP and cell death in vivo using Acridine Orange (AO) and Ethidium Bromide (EB) were applied. The excretion product of Shigella dysenteriae (SdyEP) effect was expressed in terms of larval mortality and dependent dilution rather than incubation time. The larval population surviving treatment with Shigella excretion product presents severe morphological effects. The larval population generally presents notable severe morphological damage, the necrosis state is represented by the opacity of the larvae after being treated for 24 h (b) compared to control. Other changes associated with larval anatomy were also observed; particularly the caudal end curvature was significant into 10%. The use of AO/EB revealed a distribution pattern from fluorescence into green and orange in surviving larvae SdyEP poisoning, there was a large population of dead cells around the anal and caudal region as evidenced by the presence of orange nuclei in greater numbers as controls in the larvae. The results support the application of coloring AO/EB in Zebrafish experimental...

En el campo de los estudios de toxicidad aguda inducida por agentes bacterianos, las toxinas Shiga resultan relevantes debido a la severidad de las enfermedades extra-intestinales que causan. Numerosos estudios han demostrado que la toxina Shiga induce la apoptosis en diferentes tipos de células, sin embargo, este importante proceso ha sido poco estudiado en modelos experimentales in vivo. En este estudio, fueron evaluados los efectos del productos de excreción de Shigella dysenteriae (PESdy), sobre estadios larvarios de pez cebra (Danio rerio), un modelo animal con muchas ventajas sobre otros modelos experimentales in vivo utilizados tradicionalmente. Tanto la recolección de los huevos y larvas de pez cebra, así como la obtención del producto de la excreción, se realizaron de acuerdo a los estándares de laboratorio. Poblaciones larvarias, fueron tratadas con distintas soluciones; pura y diluidas, 10-1, 10-2, 10-3 , 10-4 and 10-5 v/v de PESdy. La muerte celular in vivo, usando naranja de acridina (NA) y bromuro de etidio (BE) fue evaluada. El efecto del PESdy, se expresó como dependiente de la concentración y del tiempo de exposición. La población de larvas sobrevivientes, presentaron curvatura troncal en un 10 por ciento, en relación a los controles. La necrosis se puso en evidencia a través de la opacidad de las larvas después de 24 h. El uso de NA/BE reveló un patrón de distribución de la fluorescencia en verde y naranja en larvas sobrevivientes al tratamiento. Una gran población de células muertas, alrededor de la región anal y caudal, se ponen en evidencia por la presencia de núcleos de naranja en mayor número que en los controles. Los resultados apoyan la aplicación de la coloración NA/BE en modelo experimental...

Prevention and inhibition of TC-1 cell growth in tumor bearing mice by hpv16 e7 protein in fusion with shiga toxin B-subunit from Shigella dysenteriae

For immunotherapy of human papillomavirus [HPV] -16-associated cervical cancers the E7 protein is considered a prime candidate. However it is a poor inducer of cytotoxic T-cell response, when being used as a singular antigen in protein vaccination. Hence, in this study we focused on the utilization of a vaccine delivery system for prevention or treatment of cervical cancer. In this experimental study, we designed and evaluated a novel fusion protein comprising HPV16 E7 antigen fused to Shiga toxin B-subunit [STxB] as both an antigen vector and an adjuvant. Then we designed two preventive and therapeutic tumor models to investigate the prevention and inhibition of TC-1 cell growth in female C57BL/6 mice, respectively. In each model, mice were immunized with the recombinant protein of E7-STxB or E7 without any adjuvant. We demonstrated that prophylactic immunization of E7-STxB protected mice against TC-1 cells. Also in the therapeutic model, E7-STxB inhibited TC-1 tumor growth inlungs. The results were significant when compared with the immunization of E7 singularly. We concluded that immunization with the E7-STxB protein without any adjuvant could generate anti-tumor effect in mice challenged with TC-1 cells. This research verifies the clinical applications and the future prospects of developing HPV16 E7 therapeutic vaccines fused to immunoadjuvants

Effects of lamivudine on growth of intestinal characteristic bacteria by microcalorimetry in vitro / 药学学报

The study is aimed to investigate the effect of lamivudine on growth and metabolism of three intestinal characteristic bacteria (namely, Bifidobacterium adolescentis, Escherichia coli and Shigella dysenteriae). The growth condition of the three bacteria was quantitatively evaluated by microcalorimetry with four characteristic parameters of the thermal power-time curves, including the growth rate constant (k), thermal power (p), time to peak (t) and calorific value (Q). The results showed that the IC50 value of lamivudine on B. adolescentis was 200 microg x mL(-1), and the IC50 values of lamivudine on S. dysenteriae and E. coli were higher than 3 000 microg x mL(-1) and 6 000 microg x mL(1), respectively. Therefore, lamivudine made different inhibitory effects on the three bacteria, in which the B. adolescentis was most susceptible to lamivudine. This work showed that taking lamivudine chronically is likely to affect the balance of good flora in the intestinal tract, and might increase endotoxin release, leading to inflammation and disease progression in hepatopathy.

Microcalorimetric investigation on the interaction of six alkaloids from rhizoma coptidis / 药学学报

How to identify active constituents of traditional Chinese medicines (TCMs) and study their interactions are key problems in the development of TCMs. The inhibitory effect of six alkaloids from Rhizoma Coptidis (RC) on Shigella dysenteriae (S. dysenteria) growth had been investigated by microcalorimetry in this study. Main active constituents of RC were confirmed by comparing their contributions to the bacteriostatic effect, and the interactions among active constituents were further researched. According to the result, in 0.8 mg-mL-1 extract of RC, the contributions of six active alkaloids including berberine, coptisine, epiberberine, palmatine and the combination of jatrorrhizine and columbamine were 52.83%, 36.31%, 2.49%, 4.27% and 3.21%, respectively. Therefore, berberine and coptisine were the main active constituents of RC that inhibited the growth of S. dysenteria. The study of interactions among the six alkaloids indicated that, 1 there were some contstituents antagonizing the inhibitory effect of RC, 2 there was a synergy effect between berberine and coptisine, 3 there were additive effects between other four alkaloids and the main active constituents. These results may provide some useful references for the establishment of the quality standard for RC and the development of multi-component TCMs.

Detection and drug resistance analysis of extended-spectrum beta-lactamases-producing Shigella in pediatric patients / 中华儿科杂志

<p><b>OBJECTIVE</b>To investigate the occurrence and drug resistance of extended-spectrum beta-lactamases (ESBLs)-producing strains of Shigella in pediatric patients, so as to provide information for clinical treatment.</p><p><b>METHOD</b>A total of 59 strains of Shigella were isolated from stool specimens of hospitalized children with shigellosis from January 2004 to December 2008. The broth dilution test recommended by Clinical and Laboratory Standards Institute (CLSI) was performed to detect the ESBLs producers. Susceptibility test was carried out by agar dilution method. Escherichia coli ATCC25922 and Klebsiella pneumonia ATCC700603 were used as quality control strains.</p><p><b>RESULT</b>Of the 59 isolates, 21 (35.6%) strains were identified as ESBLs producers. All of the 21 strains were detected by cefotaxime and cefotaxime/clavulanic acid, only 5 (23.8%) were detected by ceftazidime and ceftazidime/clavulanic acid. Both ESBLs and non-ESBLs producers showed high resistance to penicillins. The resistance of ESBLs-producing strains to third and fourth-generation cephalosporins, aztreonam was significantly higher than that of non-ESBLs-producing strains, as well as sulphonamides and quinolones. The drugs sensitive to ESBLs producers were imipenem, meropenem, piperacillin/tazobactam, cefoperazone/sulbactam and cefoxitin, with resistance rate of 0.0%, 0.0%, 14.3%, 9.5%, 14.3%, respectively.</p><p><b>CONCLUSION</b>The prevalence of ESBLs-producing Shigella in pediatric patients is at a high level in this area, and the enzyme-producing strains are multidrug resistant. It is recommended that the detection of ESBLs in Shigella should be carried out by microbiological laboratories. Any of the above 5 antibiotics of low resistance should be used according to the patient's condition.</p>

A case of atypical hemolytic uremic syndrome as an early manifestation of acute lymphoblastic leukemia / 소아과

Hemolytic uremic syndrome (HUS) is the most common cause of acute renal failure in children younger than 4 years and is characterized by microangiopathic hemolytic anemia, acute renal failure, and thrombocytopenia. HUS associated with diarrheal prodrome is usually caused by Shiga toxin-producing Escherichia coli O157:H7 or by Shigella dysenteriae, which generally has a better outcome. However, atypical cases show a tendency to relapse with a poorer prognosis. HUS has been reported to be associated with acute lymphoblastic leukemia (ALL) in children. The characteristics and the mechanisms underlying this condition are largely unknown. In this study, we describe the case of an 11-year-old boy in whom the diagnosis of ALL was preceded by the diagnosis of atypical HUS. Thus, patients with atypical HUS should be diagnosed for the possibility of developing ALL.

Serogrupos y susceptibilidad antimicrobiana en cepas de Shigella / Serogroups and antimicrobial susceptibility in Shigella strains

Shigella spp es uno de los agentes causales más importantes de diarrea aguda en los niños. La presente investigación tuvo como objetivo conocer la frecuencia de serogrupos y la susceptibilidad antimicrobiana a los fármacos de elección y a los alternativos. MÉTODOS. Se realizó un estudio descriptivo y retrospectivo entre enero de 2004 y diciembre de 2006 a partir de 34 cepas de Shigella spp. aisladas en heces de niños menores de 5 años ingresados en el Hospital Aleida Fernández Chardiet (Municipio Güines) a causa de enfermedad diarreica aguda. RESULTADOS. Los serogrupos encontrados fueron S sonnei (70,5 por ciento) y S flexneri (29,5 por ciento). Ambos serogrupos mostraron altos niveles de resistencia al trimetoprim-sulfametoxazol y a la ampicilina, ademas en las cepas de S sonnei se encontró resistencia al ácido nalidíxico y en las de S flexneri al cloranfenicol. Todas las cepas mostraron altos porcentajes de sensibilidad a la ceftriaxona, norfloxacina y ciprofloxacina. El 70 por ciento de las cepas de S sonnei fueron multirresistentes. El patrón de multirresistencia (ampicilina, trimetoprim-sulfamtetoxazol y Acido nalidíxico) se encontró en ambos serogrupos. CONCLUSIONES. La determinación y vigilancia de los patrones de resistencia facilita el control de la política de uso de antibióticos en la región estudiada y previene el surgimiento de cepas resistentes a fármacos de nueva generación.

Shigella ssp. is one of the more important causal agents of acute diarrhea in children. Present research has as aim to know serogroups frequency and antimicrobial susceptibility to choice drugs, and to its alternatives. METHODS: A descriptive retrospective study was carried out between January 2004 and December 2006 of 34 strains of Shigella isolated from children lower than 5 years admitted in Aleida Fernßndez Chardiet Hospital in Güines Municipality by acute diarrheic disease. RESULTS: Serogroups included S sonnei (70,5 percent), and S flexeneri (29,5 percent). Both serogroups showed high levels of resistance to Trimethoprim-Sulfamethoxaxole and to Ampicillin and to in strains of S sonnei there was resistance to nalidixic acid, and in that of S flexeneri, to Chloramphenicol. All strains showed high percentages of sensibility to Cephtriaxone, Norphloxacine, and to Cyprophloxacine. The 70 percent of strains of S sonnei were multi-resistant. Multiresistance pattern (Ampicillin, Trimetroprim-Sulfamethoxaxole and nalidixic acid) was present in both serogroups. Assessment and surveillance of resistance patterns allow control of policy on use of antibiotics in study region, and to foresee rise of strains resistant to new generation-drugs.

Antibiotic susceptibility and plasmid profiles of shigella species in Sudan

This study was carried out to determine the antibiotic susceptibility, plasmid profile and conjugative abilities of Shigella species isolated from different towns in Sudan during 2005-2007. Stool specimens were collected in Carry Blair transport medium from patients presenting with diarrhea from different sites in Sudan between the years 2005-2007. All specimens were inoculated on Mac Conkey' s agar and Xylose Lysine Dioxycholate [XLD] [Mast group Ltd. Merseyside UK]. Bacteria was isolated and subjected to different antibiotics to detect sensitivity and transference of resistance. One hundred and fourteen Shigella isolates were included in the study. Eighty [70.1%] were Shigella flexeneri representing the dominant isolate, followed by 20 [17.5%] isolates of Shigella dysenteriae, 9 [7.9%] Shigella sonnei and 5 [4.5%] Shigella boydii. Most of the isolates showed resistance to streptomycin [70%], tetracycline [52%] and co-trimoxazole [43%]. They were highly sensitive to norfioxacin [97%], nalidixic acid [95%], gentamicin [89%] and chloramphenicol [77%]. Multi-drug resistance to two or more antibiotics was apparent in most of the isolates [64, 56.1%]. Fifty nine of the resistant Shigella isolates were studied for their ability to transfer resistance to the donor E. coli K[12] by conjugation. Of these, six were able to transfer resistance to streptomycin, tetracycline and co-trimoxazole. Extraction of the plasmid DNA from both donors and trans-conjugants showed a single type of plasmid with a molecular weight of 4.6 Kb. The transfer of multi-drug resistant plasmids and the emergence of antibiotic Shigella and other bacterial species should raise the awareness and the seriousness of the uncontrolled [unsupervised] use of antibiotics in the medical practice

Prevalence of acute diarrhoea in Kathmandu valley.

This retrospective study was conducted during January to September in the year 1997. Three hundred and forty nine stool samples were collected from diarrhoea patients from different places of Kathmandu valley and examined at National Public Health Laboratory (NPHL), Teku, Kathmandu. Acute diarrhoea becomes epidemic in rainy season and is a major public health problem of the city. In this study, people with poor hygiene practice and poor education were infected more than other people. Among the 349 patients with the gastrointestinal disease, 26.0% were found to have bacterial infection. Out of which, 88 (25.1%), one (0.28%), one (0.28%), and one (0.28%) were found to be Vibrio cholerae 01, Vibrio cholerae 0139, Shigella dysenteriae and Escherichia coli respectively. Cholera cases were found almost throughout the year in the city though the numbers increased during the rainy season. It was highest during July (34.6%) followed by August (32.35%), September 32% and June (6.89%). The uncommon species of Vibrio i.e. Vibrio cholerae 0139 was also found in the study. Higher prevalence was found in urban areas (83.52%) than in rural areas (16.48%). Antimicrobial susceptibility testing of bacterial isolates showed that Ciprofloxacin (97.85%) was found to be the most effective antibiotic followed by Tetracycline (92.34%), Erythromycin (92.34%), Norfloxacin (93.34%), Cholramphenicol, Ampicillim, but Cotrimoxazole were found to be resistant to all isolated Vibrio cholerae.

[ study of sub-MIC ciprofloxacin effects on Shigella dysenteriae]

Shigella dysenteriae causes one of the most acute kinds of diarrhea which could be established as chronic infection with alternative periods of recurrence. Administration of normal doses of antibiotics will suppress microbial infections; however it is possible to control these infections by consumption of sub-MIC doses of certain antibiotics. In this basic study, a strain of Shigella dysenteriae [PTCC:1188] was used. After determination of MIC by microdilution method in Muller-Hinton Broth and MBC in Muller-Hinton Agar, the different dilutions [1/2,1/4,1/8] of MIC were prepared in order to study the sub-MIC effects of ciprofloxacin on some traits of Shigella dysenteriae. The results showed that different sub-MIC dilutions of ciprofloxacin could cause morphological changes in Shigella. The Shigella cells became filamentous in 1/2 MIC whereas this configuration was weaker in 1/4 MIC and 1/8 MIC. Meanwhile, the appearance of colonies was changed significantly due to the higher concentrations of sub-MIC. Some of the biochemical traits were affected by sub-inhibitory concentrations of ciprofloxacin. Ciprofloxacin is a drug of choice for shigellosis. According to the results of this study, treatment of Shigella infections would be possible by lower doses of ciprofloxacin

Occurrence of some enteric pathogens in raw milk and some dairy products

110 samples of dairy products were collected from different localities and farmer's houses [40 raw milk samples, 20 raw cream samples, 30 Kariesh cheese samples and 20 yoghurt samples]. Samples were examined microbiologically for the presence of enteric pathogens. In raw milk, E. coli, Shigella dysenteriae, Salmonella enterica indiana gr. B [04, 12-H, Z-H2 1, 7], Yersinia enterocolitica and klebsilla pneumoniae could be isolated from 27.5%, 7.5%, 2.5%, 5% and 2.5% of examined samples respectively In raw cream, E coil and Shigella dysenteriae could be isolated from 15% and 5% of examined samples respectively. In Kariesh cheese, E. coli, Shigella dysenteriae, Salmonella enterica indiana, yersinia enterocolitica and Kiebsilla pneumoniae could be isolated from 43.3%, 16.6%, 3.3%, 3.3% and 6.6% of examined samples respectively. For yoghurt, E. coil and Yersinia enterocolitica could be isolated from 20% and 10% of examined samples respectively. From different 25 tested strains, 17 strains [68%] were positive for production of enterotoxin [7 strains of E. coli, 3 strains of Shigella dysenteriae, 2 strains of Salmonella enterica indiana, 3 strains of Klebsilla pneumoniae and 2 strains of Yersinia enterocolitica]. The public health importance of isolated organism as well as recommendation for prevention of microbial contamination of dairy products were also discussed

Microcalorimetric studies of the action on four organic acids in Radix isatidis on the growth of microorganisms / 生物工程学报

The actions of four organic acids in Radix isatidis, a traditional Chinese medicinal (TCM) herb, on Escherichia coli, Staphylococcus aureus and Shigella dysenteriae growth were investigated by microcalorimetry. The four organic acids were syringic acid, 2-amino-benzoic acid, salicylic acid and benzoic acid. The power-time curves of Escherichia coli, Staphylococcus aureus and Shigella dysenteriae growth with and without organic acids were acquired, meanwhile the extent and duration of inhibitory effects on the metabolism were evaluated by growth rate constants (k1, k2), maximum heat-output[0] power (P(m)) and peak time (t(m)). The inhibitory activity varied with different drugs. The sequences of anti-microbial activity of the four organic acids on Escherichia coli, Staphylococcus aureus and Shigella dysenteriae were all: syringic acid > 2-amino-benzoic acid > salicylic acid > benzoic acid. And benzoic acid promoted the growth of Staphylococcus aureus and Shigella dysenteriae. This study provides a basis for the further study on Radix Isatidis.

Analysis on incidence of bacillary dysentery in Jinan municipality from 1951 to 2005 / 中华预防医学杂志

<p><b>OBJECTIVE</b>To explore the epidemic characteristics of bacterial dysentery in Jinan municipality, and to provide scientific basis for effective strategy for bacterial dysentery control.</p><p><b>METHODS</b>The epidemiological characteristics of bacillary dysentery in Jinan from 1951 to 2005 were analyzed. A total of 485,333 cases in the span of 50 years were recorded, while the population-based case distribution was less than the total cases due to the data incompleteness during the Cultural Revolution.</p><p><b>RESULTS</b>The incidence of bacillary dysentery in Jinan has been decreasing by years with average incidence rate of 283.10/100,000. The significant differences were observed among the incidence rates of various ages(chi2 = 14.99, P < 0.05). There were four epidemic peaks, and all the incidence rates were about 1000/100,000. Age of onset mainly concentrated in the 0-4 years old, 20-years old and 30-years old. In terms of occupational distribution, workers accounted for 30.31%, the living-scattered children accounted for 22.71%, and the farmers accounted for 17.90%. The incidence focus was from July to September, which accounted for 71.57%. The peak of incidence emerged in August. The highest incidence in urban was 550.94/100,000.</p><p><b>CONCLUSION</b>Through the efforts of several generations of health workers, the incidence of bacillary dysentery in Jinan has been basically brought under control. Further step should be taken for the control of bacterial dysentery in urban areas and the management of bacterial dysentery in rural areas. Moreover, the biological characteristics of F2a should be a focus for the future study.</p>

All blood, No stool: enterohemorrhagic Escherichia coli O157:H7 infection

Enterohemorrhagic Escherichia coli serotype O157:H7 is a pathotype of diarrheagenic E. coli that produces one or more Shiga toxins, forms a characteristic histopathology described as attaching and effacing lesions, and possesses the large virulence plasmid pO157. The bacterium is recognized worldwide, especially in developed countries, as an emerging food-borne bacterial pathogen, which causes disease in humans and in some animals. Healthy cattle are the principal and natural reservoir of E. coli O157:H7, and most disease outbreaks are, therefore, due to consumption of fecally contaminated bovine foods or dairy products. In this review, we provide a general overview of E. coli O157:H7 infection, especially focusing on the bacterial characteristics rather than on the host responses during infection.

Evaluación de la actividad antimicrobiana de bacterias ácido lácticas. Parte I / Evaluation of the antimicrobial activity of lactic acid bacteria. Part I

Se evaluó la actividad antimicrobiana de seis diferentes bacterias  cido lácticas sobre Escherichia coli, Salmonella enteritidis y Shigella dysenteriae, bacterias patógenas del tracto gastrointestinal. Los ensayos determinaron que todas ellas presentaron acción antimicrobiana sobre las bacterias entéricas, destacando Lactobacillus fermentum, quien produjo un efecto bactericida.

The antimicrobial activity of six different lactic acid bacteria was evaluated on Escherichia coli, Salmonella enteritidis and Shigella dysenteriae, pathogenic bacteria of the gastrointestinal tract. Tests determined that all of them presented antimicro bial action on the enteric bacteria, especially Lactobacillus fermentum, that generated a bactericidal effect.