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Introduction: Gastrointestinal infections affect many people annually. The most common bacterial agents involved in these infections are enteropathogenic bacteria and in the continuation of using broad‑spectrum antibiotics, Clostridium difficile‑associated diarrhea is involved, especially in hospitalized patients. The aim of the present study was to investigate the pattern of antibiotic resistance among enteropathogenic bacteria. Materials and Methods: In this cross‑sectional study, 163 samples of patients with diarrhea in Dezful Ganjavian Hospital were examined. The samples were cultured in MacConkey, Hektoen enteric agar and GN broth, and cycloserine cefoxitin fructose agar media and incubated under standard conditions. In order to identify enteropathogenic bacteria, biochemical tests and serological confirmatory tests were used. Antibiotic resistance pattern of the isolates was investigated by Kirby–Bauer disk diffusion susceptibility test. Results: The frequency of pathogenic bacteria includes 41.1% of Shigella flexneri, followed by 41.1% of S. sonnei, 6.7% of Enteropathogenic E. coli, 5.5% of Salmonella enterica Serogroup B, and 5.5% of Shigella dysenteriae. The results revealed a total of 46 patients with orders regarding C. difficile culture, no C. difficile was isolated from the samples. The studied isolates showed the highest resistance to trimethoprim‑sulfamethoxazole, and ceftriaxone (88.3%), and the most effective antibiotic in the treatment of patients was ciprofloxacin with 86% sensitivity. Conclusion: Susceptibility to antibiotics was different among the isolates, which shows that the early identification of the infection agent and the selection of the correct antibiotic treatment are effective in improving the gastrointestinal infection and preventing the spread of the infection. [ABSTRACT FROM AUTHOR]

INTRODUCCIÓN: las gastroenteritis agudas (GEA) constituyen un grave y ocupante problema de Salud Pública. OBJETIVO: resultó de interés buscar bacterias (Salmonella spp. y Shigella spp.) virus (Rotavirus y Adenovirus) y parásitos en heces de niños con diarrea en un Hospital de la provincia de Córdoba, Argentina; para trazar un perfil etiológico en nuestra región. MATERIALES Y MÉTODO: se analizaron 137 muestras de heces de pacientes infanto-juveniles ambulatorios durante un año. RESULTADOS: 31 de las 137 muestras analizadas arrojaron resultados positivos (22,62%; n=137). De los casos positivos (n=31), 61,29% (19; n=31) correspondieron a aislamientos de los géneros Salmonella y Shigella, 9,67% (3; n=31) a diagnóstico de Rotavirus y 22,58% (7; n=31) a diagnóstico de parásitos intestinales. Dos de las muestras clínicas positivas presentaron coinfección (6,45 %); giardiosis y shigelosis y giardiosis y Rotavirus, respectivamente 25,80% de las bacterias estudiadas se presentaron en niños de 3 y 4 años de edad; 9,67% de las parasitosis, en niños de 6 y 7 años de edad y 6,45% Rotavirus, en niños de 1 y 2 años de edad. No hubo diferencias significativas en la distribución por sexo. DISCUSIÓN Y CONCLUSIONES: la vigilancia de las diarreas basada en los diagnósticos microbiológico y parasitológico provee información relevante que complementa el seguimiento clínico y epidemiológico creando un mapeo de la circulación de los agentes etiológicos en una determinada región.

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Background: The use of biologically activated carbon (BAC) in drinking water purification is reviewed. Aim: The study was aimed to determine the efficiency of natural adsorbent with antibacterial effects against the strains of E. coli, Shigella spp. and Faecalis bacteria which are found in stimulated water samples. Methods: This was an analytical laboratory based study. The study was carried out at laboratory of Ahfad University for Women at Omdurman in Khartoum state. Two samples of mango seeds and date’s stone were used to carry out these experiments. Mango and date were brought from the local market (Sug El Arabi ). The general process to produce activated carbon is based on carbonizing and activating the carbon aqueous precursor material. The powder was put in crucible and 1 gram of zinc chloride was added to it. It was incinerated at 350 0C for not less than 3 hours in an oven. It was cooled in a room temperature. Results Activated carbon prepared from mango seeds and date’s stone was found to be very active as antibacterial against E.coli, Shigella and E.faecalis bacteria. The result showed zone of inhibition for each bacteria. The greater zone of inhibition was against E.faecalisdone by both samples. The more effective sample in the three strains was AC from mango seeds. Conclusions: These antibacterial results are good indicators to use natural adsorbent in food processing, sugar purification and food industry.

Background: The importance of accurate diagnosis of infectious diseases is central and crucial to the effectiveness of treatment and prevention of the associated long-term complications of such infections. The objective of this study was therefore to determine the accuracy of the Widal antibody titre test in the diagnosis of typhoid fever relative to the gold standard blood culture technique. Methodology: A total of 40 students attending the Olabisi Onabanjo University Health Services, Ago-Iwoye, Ogun State, Nigeria on account of suspected typhoid fever by positive Widal test (= 1/80) and not on antibiotic therapy, were recruited for the study. Stool and blood samples were collected from each participant and analysed at the medical laboratory of the health center using conventional culture techniques and confirmation of isolates by simplex and multiplex polymerase chain reaction (PCR) amplification assays of hilA (Salmonella enterica), ipaH (Shigella spp), rfc (Shigella flexneri) and wbgZ (Shigella sonnei) genes. Antibiotic susceptibility testing (AST) of isolated bacteria to 10 panel of antibiotics was done using the Kirby Bauer disk diffusion test and interpreted according to the Clinical and Laboratory Standards Institute (CSLI) guideline. Results: Of the 40 patients with suspected typhoid fever by the Widal test, 9 yielded Salmonella enterica giving a 22.5% isolation rate, with Salmonella enterica serovar Typhi (Salmonella Typhi) confirmed as sole bacterium from blood cultures in 5 (12.5%) patients and co-infection of Salmonella and Shigella from stool samples in 4 (10.0%) patients. A total of 52 enteric bacteria isolates were recovered from blood and stool samples of the 40 patients made of Salmonella enterica 9 (17.3%), Shigella spp 20 (38.5%), S. flexneri 9 (17.3%) and S. sonnei 14 (26.9%). All the enteric isolates were multi-drug resistant (MDR), with resistance rates to the antibiotic panel ranging from 33.3%-100%, and all the isolates were resistant to ceftriaxone and pefloxacin. Salmonella isolates were also 100% resistant to nitrofurantoin, ofloxacin and ciprofloxacin; S. flexneri were 100% resistant to nitrofurantoin, amoxicillin, cotrimoxazole, ofloxacin and ciprofloxacin; and S. sonnei were 100% resistant to nitrofurantoin and cotrimoxazole. Conclusion: These results showed that only 12.5% of typhoid fever diagnosis by Widal test had Salmonella Typhi isolated from their blood cultures while Salmonella enterica and Shigella spp were isolated from stool samples of other cases. There is need to adopt culture techniques for laboratory diagnosis of febrile illnesses in order to improve treatment regimen. The fact that AST can also be performed with culture technique could further guide antibiotic prescription and reduce the risk of emergence of resistant bacteria. [ABSTRACT FROM AUTHOR]

Background: Shigella spp. is the cause of dysentery and is widespread worldwide. On the other hand, antibiotic resistance is increasing in this bacterium. Bioinformatics is a new approach to vaccine and drug design involving the selection of appropriate antigens. This study aimed to design a chimeric protein consisting of IpaD, StxB, and TolC proteins from Shigella through a bioinformatics approach as an immunogen candidate. Methods: The sequences of ipaD, stxB, and tolC genes were obtained. Additionally, the immunogenic regions of the associated protein, physicochemical characteristics, protein structures, B and T cells epitopes, and molecular docking were determined using in silico servers. Besides, the chimeric gene was synthesized following sequence optimization by utilizing the codon usage of Escherichia coli ( E. coli). The expression of the recombinant protein was confirmed via SDS-PAGE and Western blot technique. Results: The residues 41-160 of IpaD, 21-89 of StxB, and 40-335 of TolC were selected. According to half-life, instability, and buried indices, IpaD-StxB-TolC was selected as the best arrangement. The Ramachandran plot showed that 97.077% of the amino acids were in the favored area. Linear and conformational epitopes were also present throughout the chimeric protein sequence. Moreover, the C-ImmSim server indicated that IgG and IgM titers could reach desirable values by the third injection .Furthermore, the stability of the mRNA-optimized gene was enhanced, increasing the Codon Adaptive Index (CAI) to 0.9. Finally, the chimeric gene was transferred to E. coli BL21, and the expression of the 60.6 kDa recombinant protein was confirmed. Conclusion: The results indicated that the recombinant protein could act as a proper immunogen candidate against Shigella spp. [ABSTRACT FROM AUTHOR]

Background: Diarrhoea remains one of the leading causes of childhood mortality globally. Recent epidemiological studies conducted in low-middle income countries (LMICs) identified Shigella spp. as the first and second most predominant agent of dysentery and moderate diarrhoea, respectively. Antimicrobial therapy is often necessary for Shigella infections; however, we are reaching a crisis point with efficacious antimicrobials. The rapid emergence of resistance against existing antimicrobials in Shigella spp. poses a serious global health problem. Methods: Aiming to identify alternative antimicrobial chemicals with activity against antimicrobial resistant Shigella, we initiated a collaborative academia-industry drug discovery project, applying high-throughput phenotypic screening across broad chemical diversity and followed a lead compound through in vitro and in vivo characterisation. Results: We identified several known antimicrobial compound classes with antibacterial activity against Shigella. These compounds included the oral carbapenem Tebipenem, which was found to be highly potent against broadly susceptible Shigella and contemporary MDR variants for which we perform detailed pre-clinical testing. Additional in vitro screening demonstrated that Tebipenem had activity against a wide range of other non-Shigella enteric bacteria. Cognisant of the risk for the development of resistance against monotherapy, we identified synergistic behaviour of two different drug combinations incorporating Tebipenem. We found the orally bioavailable prodrug (Tebipenem pivoxil) had ideal pharmacokinetic properties for treating enteric pathogens and was effective in clearing the gut of infecting organisms when administered to Shigella-infected mice and gnotobiotic piglets. Conclusions: Our data highlight the emerging antimicrobial resistance crisis and shows that Tebipenem pivoxil (licenced for paediatric respiratory tract infections in Japan) should be accelerated into human trials and could be repurposed as an effective treatment for severe diarrhoea caused by MDR Shigella and other enteric pathogens in LMICs. Funding: Tres Cantos Open Lab Foundation (projects TC239 and TC246), the Bill and Melinda Gates Foundation (grant OPP1172483) and Wellcome (215515/Z/19/Z).

Globally, it is estimated that there are 2 billion cases of diarrhoeal disease each year, with 525,000 children under the age of 5 years, dying from diarrhoea. This also affects 1 in 5 people in the UK each year. Rapid diagnosis, appropriate treatment and infection control measures are, therefore, particularly important. Currently, Public Health Wales and England Microbiology Division test for five key bacterial gastrointestinal pathogens, i.e. Escherichia coli O157 (VTEC), Shigella dysenteriae, Salmonella spp., Campylobacter spp. and Clostridioides difficile. There is, however, a poor success rate with identification of these pathogens, leaving the patient at risk from untreated infections. This study has developed effective and reliable tools with a high positive outcome for diagnosis of diarrhoeal infection. The study blindly analysed 592 samples, with the most abundant species being Shigella sonnei at 15%, and the top genus Bacteroides at 26%. Campylobacter spp. had an abundance of 4%, Clostridium difficile 3%, and Salmonella spp. 0.2%. There were also significant differences in abundance at genus level, between the Flemish Gut project and diarrhoea samples, with respect to Shigella (0.2%) and Campylobacter (0.1%). The project introduced a novel Shigella spp. (Escherichia) threshold of 5.32% to determine (Escherichia) a healthy or unhealthy community. A DMBiome model was developed to integrate the 5.32% threshold of Shigella spp., the Public Health laboratory tested pathogens, and two emerging enteropathogens. The overall positive outcome was that 89% of all samples were diagnosed with diarrhoea infections, leaving 11% unknown. [ABSTRACT FROM AUTHOR]

there are numerous pathogens of different life form such as bacteria, parasites and viruses that cause diarrheal infectious diseases in humans. the objective of this article is to review the licensed vaccines for viral pathogens such as rotaviruses and bacteria as cholera and typhoid (ti21a, Vi Polysaccharide) and also based on the pathogen, its morphology, immunity triggering and vaccine manufacturing techniques, the progress of vaccines against norovirus, Shigella and enterotoxigenic Escherichia coli. the strategy of ongoing researches has been focused to develop vaccines that would confer immunity against many serotypes of the same pathogen. [ABSTRACT FROM AUTHOR]

The globally increasing incidence of antibiotic resistance in pathogenic microorganisms such as Shigella, a cause of human acute gastrointestinal infections, calls for developing effective alternatives. In this study, the antibiotic resistance pattern, extended-spectrum β-lactamase (ESBL)-production, and molecular characteristics of 70 multidrug-resistant isolates belong to the two most frequent species of Shigella genus, that is, Shigella sonnei (44 isolates) and Shigella flexneri (26 isolates) were investigated. These isolates were used to evaluate both specificity and activity of Shigella-specific bacteriophages, vB_SflS-ISF001, vB_SsoS-ISF002, and a cocktail of both. Twelve out of the 21 tested resistance genes were detected in the isolates. About 59% of S. sonnei and 46% of S. flexneri isolates were identified as ESBL producers. The bacteriophages showed a high efficiency of plating (EOP ≥0.5) in about 75% of the isolates. Moreover, the growth of >85% of the isolates was inhibited by the phage cocktail of vB_SflS-ISF001 and vB_SsoS-ISF002. The phage cocktail was effective against a wide range of ESBL-positive and -negative isolates of S. sonnei and S. flexneri. Therefore, this phage cocktail has the potential to inhibit or significantly decrease the spread of drug-resistant Shigella in humans, food chains, and water/wastewater sanitation systems. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate the presence of Shigella spp. in vegetable salads and verify the antibiotic resistance of the obtained samples. One hundred and sixty samples of ready-to-eat salads were obtained from five places of sale in the city of Lujan, province of Buenos Aires, Argentina, during the months of January 2017 to December 2018. The presence of Shigella spp. and their antibiotic resistance was determined following standard microbiological methods. Shigella was isolated from 13 samples (8.12%) by biochemical analysis and serological typing. Of the 13 isolates, four of Shigella flexneri serotype 2 showed a multidrug resistance to ampicillin, chloramphenicol and trimethoprim-sulfamethoxazole, while the rest showed resistance to a single antibiotic. It can be concluded that prepared salads, ready to consume, possess a high risk of contracting shigellosis because they are consumed without prior treatment. [ABSTRACT FROM AUTHOR]

Introduction: Food safety concerns remain a challenge across nations and among citizens. Microbial contamination of foods and antibiotic resistance constitutes a global threat to food security. The present study assessed microbial quality of "Tuo‐Zaafi" sold in the Tamale metropolis as well as antibiotic resistance of isolates from these products. Results: Samples were collected aseptically and transported to the Spanish laboratory complex of the University for Development Studies, Ghana, for microbial analysis. E. coli which recorded the highest occurrence was detected in 50% of the T.Z samples with bacterial loads ranging from < 100 to 2.3 × 106 cfu/g (4.49 × 105 ± 5.72 × 104 cfu/g). Salmonella spp and Staphylococcus aureus recorded the least occurrence representing 33.3%. There were significant differences in the levels of E. coli, Shigella spp, Salmonella spp, and Staphylococcus aureus (p < .001) across the four zones demarcated. Results of the antibiotic test revealed higher resistance to the antibiotics employed in the present study (81%). Susceptibility of microbes to ciprofloxacin (100%) was the highest, and higher resistance to gentamycin (100%) was observed in this study. Conclusion: The study revealed that T.Z sold in the business district of Tamale could constitute a likely health risk to consumers especially when it is consumed in a cold state. It is hereby recommended that the Food and Drugs Authority (FDA) should enforce food hygiene laws and ensure strict adherence. [ABSTRACT FROM AUTHOR]

Shigella is the major cause of bacillary dysentery worldwide, especially in developing countries. There are several virulence factors essential for the organism to be virulent which are generally present in the virulence plasmid and on chromosomal pathogenicity islands. The present study was undertaken to determine the virulence gene profile of Shigella spp isolated from a clinical specimen and to study their significant association with common clinical symptoms and antimicrobial resistance. Sixty Shigella whole genome sequences, including 22 S. flexneri, 14 S. sonnei, 17 S. boydii and 7 S. dysenteriae were analyzed for the presence of virulence genes. The gene found predominantly in this study were ipaH (90%) followed by sigA (83%), and lpfA (78%) respectively. The virulence genes were significantly higher in S. flexneri, particularly in serotype 2 compared to S. sonnei. Interestingly, a significant association was observed between sigA gene and fever whereas sepA and sigA were found to be associated with diarrhea. Among the studied Shigella isolates, the presence of virulence genes was found higher in isolates resistant to more than three antibiotic classes. The present work revealed the varying incidence of virulence determinants among different Shigella serogroups and shows their contribution to disease severity. [ABSTRACT FROM AUTHOR]

The aim of this study was antimicrobial susceptibilityof some pathogenic bacteria isolated from fresh bovine milk Al-Hilla city. A total of 40 milk samples were collected randomly from Hilla city. Isolation of E. coli, Staphylococcus aureus and Shigella spp. were done by using enrichment media and selective media. The present study showed the levels of contamination with E. coli bacteria were isolate 15(37.5%), Staphylococcus spp. was isolated 18(45%) and Shigella spp. were 8(20%), respectively from bovine fresh milk. Antimicrobial susceptibility testing to E. coli, Staphylococcus aureus and Shigella spp. were conducted for Cephalothin,Imipenem,Gentamycin, Erythromycin, Ciprofloxacin andMeteronidazol respectively. The result of the present study shows that E. coli isolates were sensitive to Ciprofloxacin Imipenemand Gentamycin, respectively. Also in this study the high resistance of E. coli isolate to cephalothin and metronidazole. The present study showed high sensitive of Staphylococcus spp. was observed to gentamycin, Ciprofloxacin and imipenem respectively. Also in our study showed that high resistance to Erythromycin, Cephalothin and metronidazole respectively from bovine fresh milk. In present study, isolate of Shigella spp. showed highly sensitive to gentamycin, ciprofloxacin and imipenem respectively. However, in current study showed that Shigella spp. isolated resistance to Metronidazole and cephalothin respectively from bovine fresh milk. Antimicrobial susceptibility should be conducted before treating bovine milk. Consequently, reduction in transfer of resistant S. aureus, Shigella spp. and E. coli between humans and animals. [ABSTRACT FROM AUTHOR]

The objective of this study was to assess antibiotic resistance and the molecular epidemiology of shigella isolates from a case–control study of diarrhoea, conducted from 2007 to 2012 in children aged less than 5 years in Manhiça district, southern Mozambique. All isolates were tested for antimicrobial susceptibility using the disc diffusion method. Polymerase chain reaction was used to detect different molecular mechanisms of antibiotic resistance. Serotyping was performed using specific antisera. The clonal relationship of Shigella flexneri and Shigella sonnei was assessed by pulsed-field gel electrophoresis (PFGE). Of the 67 shigella isolates analysed, 59 were diarrhoeal cases and eight were controls. S. flexneri (70.1%; 47/67) was the most common species, followed by S. sonnei (23.9%; 16/67). The most prevalent S. flexneri serotypes were 2a (38.3%; 18/47), 6 (19.2%; 9/47) and 1b (14.9%; 7/47). High rates of antimicrobial resistance were observed for trimethoprim-sulfametoxazole (92.5%; 62/67), tetracycline (68.7%; 46/67), chloramphenicol (53.7%; 36/67) and ampicillin (50.7%; 34/67). Multi-drug resistance (MDR) was present in 55.2% (37/67) of the isolates and was associated with a case fatality rate of 8.1% (3/37). PFGE revealed 22 clones (16 S. flexneri and 6 S. sonnei ), among which P1 (31.9%; 15/47), P9 (17%; 8/47) and P2 (10.6%; 5/47) were the most prevalent clones of S. flexneri . In conclusion, S. flexneri was the most prevalent species, with MDR isolates mainly belonging to three specific clones (P1, P9 and P2). The case fatality rate observed among MDR isolates is a matter of concern, indicating the need for appropriate treatment. [ABSTRACT FROM AUTHOR]

Riverbed sediment is a vital component of river ecosystems and plays an important role in many geomorphological and ecological processes. However, when re-suspension occurs, pathogenic bacteria associated with sediment particles may be released into the water column, thus creating a health risk to those who use such water for drinking, household and recreational purposes. The aim of this study was to investigate the presence of bacterial pathogens Salmonella spp. and Shigella spp. in the Apies River and to ascertain whether there was any level of genetic relatedness between river water and riverbed sediment isolates of these pathogenic bacteria. A total of 124 water and sediment samples were collected from a site located on the Apies Rivers upstream of the Daspoort Wastewater Treatment Works, Pretoria, Gauteng, South Africa, between August and November 2014. In order to detect and identify the target bacteria, samples were analysed by culture-dependent and culture-independent techniques (quantitative real-time PCR). Genetic relatedness was established using Sanger sequencing of the invA gene of Salmonella spp. and ipaH of Shigella spp. Results of this study displayed the presence of the target bacteria both in the water and sediment of the river. The phylogenetic tree of Salmonella spp. revealed a ≥ 99% and 99% genetic relatedness between river water and riverbed sediment isolates for Salmonella spp. and Shigella spp., respectively. The degree of genetic relatedness between sediment and water pathogen isolates suggests that these organisms could possibly have a common origin and that there could be possible movement of microorganisms between the water column and the sediments. [ABSTRACT FROM AUTHOR]

Background: Shigellosis is a diarrheal disease caused by Shigella spp. The majority of cases and deaths occur among children less than 5 years old. In severe cases, antibiotic therapy is recommended to lessen the risk of serious complications and death. Prevalence of different Shigella species and their antibiotic resistance patterns are changing over the time. Objectives: The current study aimed at assessing the changes in the prevalence of Shigella species and their antibiotic susceptibility among 0- to 14-year-old children referred to Children’s Medical Center, Tehran, Iran, from 2009 to 2014. Methods: The results of stool cultures were retrospectively analyzed to determine the prevalence of different Shigella species, their antibiotic susceptibility patterns and their changes in the largest university affiliated pediatrics center in Tehran. Results: Among 40 700 stool cultures, 507 cases were positive for Shigella spp. Most cases occurred among children under 5 years old. Shigellosis was more prevalent among males. The most common species were Shigella sonnei and Shigella flexneri. In general, they were most sensitive to cefotaxime and most resistant to cotrimoxazole. Resistance to cefotaxime and nalidixic acid increased annually. Resistance to ampicillin had a descending trend. Resistance to cotrimoxazole remained almost constant. Conclusions: The most common species of Shigella changed from Shigella flexneri to Shigella sonnei over the years. In comparison with the previous studies, resistance to nalidixic acid increased and resistance to ampicillin decreased. The prevalence and antibiotic resistance patterns of Shigella species, at different times and regions are changing. To make appropriate decisions on treatment, it is necessary to monitor the changes. [ABSTRACT FROM AUTHOR]

Shigella spp. causes bloody diarrhea and leads to death, especially in children. Chimeric proteins containing virulence factors can prevent Shigella infection. The purpose of this study is to investigate the immunogenic and protective effect of trivalent chimeric protein containing IpaD-StxB-TolC antigens against shiga toxin, S. dysenteri and S. flexneri in vitro and in vivo conditions. Recombinant vector was transferred to E. coli BL21. The expression of the chimeric protein was confirmed by SDS PAGE and purified using the Ni-NTA column. Mice were immunized with recombinant protein and antibody titer was evaluated by ELISA. 10, 25 and 50 LD 50 of Shiga toxin neutralization was evaluated in vitro (Vero cell line) and in vivo conditions. Also, the challenge of immunized mice with 10, 25 and 50 LD 50 of S. dysentery and S. flexneri was done. The expression and purification of the recombinant protein with 60.6 kDa was done. ELISA showed increased antibody titer against the chimeric protein. MTT assay indicated that 1/8000 dilution of the sera had a 51% of cell viability against the toxin in Vero cell line. The challenge of mice immunized with toxin showed that the mice had complete protection against 10 and 25 LD 50 of toxin and had 40% survival against 50 LD 50. Mice receiving 10 and 25 LD 50 of S. dysenteri and S. flexneri had 100% protection and in 50 LD 50 the survival rate was 60 and 50%, respectively. Organ burden showed that the amount of bacterial colonization in immunized mice was 1 × 104 CFU/mL, which was significantly different from the control group. This study showed that chimeric proteins can create favorable immunogenicity in the host as vaccine candidates. • Shigella spp. causes bloody diarrhea and leads to death, especially in children. • Recombinant vaccines are a new strategy to prevent bacteria that threaten public health and their antibiotic resistance rate is increasing. • Chimeric proteins can create favorable immunogenicity in the host as vaccine candidates. • IpaD, StxB, and TolC antigens can protect mice against high doses of toxins and bacteria. [ABSTRACT FROM AUTHOR]

Introducción: la técnica de secado en perlas de vidrio se reporta como método de conservación microbiana desde hace varios años, pero la información existente es limitada. Con este antecedente, se decidió evaluar su utilidad para conservar bacterias, de origen clínico, en la colección de cultivos microbianos del Instituto Nacional de Higiene, Epidemiología y Microbiología. Métodos: se estudiaron dos cultivos de Shigella spp., mantenidas en refrigeración. Los datos de viabilidad obtenidos durante cuatro años de conservación fueron procesados con el paquete estadístico SPSS versión 15.0. El análisis estadístico incluyó el de la varianza para la comparación de las medias del recobrado de células viables para las variables tiempo de conservación, dilución y mezcla preservante, y el test de Scheffé de comparaciones múltiples post hoc para la discriminación de las medias. Fueron controladas las características fisiológicas y la respuesta a la tinción de Gram de las cepas. Resultados: no se encontraron diferencias significativas entre las mezclas preservantes utilizadas en este ensayo, y pudieron recobrarse ambas cepas durante los cuatro años de estudio. A partir de los seis meses se apreció una disminución del efecto protector en todas las mezclas. Se obtuvo variabilidad en algunos caracteres fisiológicos (indol, dulcitol y manitol), pero no para la respuesta a la tinción de Gram en ambas cepas, la que se mantuvo estable. Conclusiones:: el método resultó apropiado para mantener Shigella spp. por tiempo limitado, pero pudiera utilizarse como alternativa de conservación en laboratorios con limitados recursos a corto plazo, por su sencillez, bajo costo y efectividad, y debe garantizarse la disponibilidad de réplicas por otras técnicas.Introduction: glass bead dehydration technique has been reported as a microbial preservation method for some years, but the available information is limited. Based on this antecedent, it was decided to evaluate its usefulness to preserve bacteria of clinical origin in the collection of microbial cultures at the National Institute of Hygiene, Epidemiology and Microbiology. Methods: a study was conducted of two Shigella spp. cultures kept under refrigeration. The viability datas obtained during four years of preservation were processed with the statistical package SPSS, version 15.0. Statistical processing included analysis of variance for comparison of the mean recovery values of viable cells for the variables preservation time, dilution and preserving mix, and Scheffe's test of post hoc multiple comparisons for means discrimination. Physiological characteristics were controlled, as well as the response of strains to Gram stain. Results: no significant differences were found between the preserving mixes used in the trial, and both strains could be recovered during the four years of the study. The protective effect of all mixes was found to decrease after six months. Variability was obtained for some physiological characters (indol, dulcitol and mannitol), but response to Gram stain remained stable in both strains. Conclusions:: the method was found to be suitable to preserve Shigella spp. for a limited time, but it could be used as a short-term preservation alternative in laboratories with few resources, due to its simplicity, low cost and effectiveness. Availability should be ensured of replicas obtained by other techniques.

INTRODUCTION: Shigella spp. are Gram-negative, nonsporulating, rod-shaped bacteria that belong to the family Enterobacteriaceae and are responsible for shigellosis or bacillary dysentery, an important cause of worldwide morbidity and mortality. METHODS: We studied the antibiotic resistance profiles of 122 Shigella spp. strains (81 S. flexneri, 41 S. sonnei, 1 S. boydii) isolated from patients (female and male from 0 to 80 years of age) presenting diarrhea in different districts of the State of Pará, in the North of Brazil. The antibiotic resistance of the strains, isolated from human fecal samples, was determined by the diffusion disk method and by using the VITEK-2 system. RESULTS: The highest resistance rate found was the resistance rate to tetracycline (93.8%), followed by the resistance rate to chloramphenicol (63.9%) and to trimethoprim/sulfamethoxazole (63.1%). Resistance to at least three drugs was more common among S. flexneri than S. sonnei (39.5% vs. 10%). Six (4.9%) strains were susceptible to all the antibiotics tested. All strains were susceptible to cefotaxime, ceftazidime, ciprofloxacin, nalidixic acid and nitrofurantoin. CONCLUSIONS: High rates of multidrug resistance in Shigella spp. are a serious public health concern in Brazil. It is extremely important to continuously monitor the antimicrobial resistances of Shigella spp. for effective therapy and control measures against shigellosis.INTRODUÇÃO: Shigella spp. são bactérias Gram-negativas, não esporuladas, em forma de bastonete, pertencentes a família Enterobacteriaceae responsáveis pela shigelose ou disenteria bacilar, uma importante causa de mortalidade e morbidade mundial. MÉTODOS: Foi estudado o perfil de resistência a antimicrobianos de 122 amostras de Shigella spp. (81 S. flexneri, 41 sonnei, 1 S. boydii) isoladas de pacientes (sexo feminino e masculino com faixa etária de 0 a 80 anos) com distúrbios gastrointestinais em diferentes municípios no Estado do Pará, Brasil. A resistência antimicrobiana das amostras isoladas de coprocultura, foi determinada pelo método de difusão em disco e pelo sistema Vitek II. RESULTADOS: A maior resistência foi observada em relação à tetraciclina (93,8%), seguida de cloranfenicol (63,9%), e trimetoprimsulfametoxazol (63,1%). Multirresistência a pelo menos três antimicrobianos foi mais comum em S. flexneri comparada a S. sonnei (39,5% vs. 10%). Seis (4,9%) amostras foram sensíveis a todos antimicrobianos testados. Todas as amostras apresentaram sensibilidade a cefotaxima, ceftazidima, ciprofloxacina, ácido nalidixico e nitrofurantoína. CONCLUSÕES: As altas taxas de multirresistência de Shigella spp. são um sério problema de saúde pública no Brasil. Sendo assim, torna-se extremamente importante um monitoramento contínuo da resistência antimicrobiana de Shigella spp. para uma terapia efetiva e medidas de controle contra shigelose.

Justificación y objetivo: En la actualidad, las enfermedades de transmisión alimentaria, incluyendo las diarreas e intoxicaciones, constituyen uno de los problemas de salud pública de mayor importancia a nivel mundial, ya que ocasionan alta morbilidad y mortalidad, generan grandes costos a los servicios de salud, pérdidas económicas, demandas y pérdida de confianza de los consumidores. El objetivo del trabajo es analizar la información disponible en el Centro Nacional de Referencia en Bacteriología del INCIENSA (CNRB), de los brotes de diarrea e intoxicaciones alimentarias ocurridos en 2005, en los que se refirieron muestras clínicas o de alimentos, para identificar los agentes y vehículos de infección asociados. Materiales y métodos:Se realizó el análisis descriptivo de la información epidemiológica y de laboratorio disponible en el CNRB en relación con los brotes de diarrea e intoxicaciones alimentarias ocurridos en 2005. Resultados:Durante el período el CNRB documentó 23 brotes de diarrea e intoxicaciones alimentarias, para un total aproximado de 819 afectados, en su mayoría procedentes de la gran área metropolitana. Trece de los brotes fueron intrafamiliares (diez de ellos debidos a especies y serotipos de Shigella); sin embargo, el mayor número de enfermos se presentó en los brotes comunitarios y los que se produjeron en poblaciones cautivas, asociados a rotavirus, Escherichia coli enterotoxigénica y Clostridium perfringens productor de toxina A, con 518, 138 y 54 enfermos, respectivamente. Conclusión:Estos hallazgos evidencian deficiencias en la cadena de transporte, conservación y manipulación de los alimentos, así como en la higiene personal, y pueden ser de utilidad para la implementación de intervenciones inmediatas.

Although ionising radiation has been shown to kill human pathogens Shigella spp. and Aeromonas spp. on various food products, there is lack of information regarding the relative efficacy of gamma radiation against their free-living planktonic and biofilm-associated cells. The radiation sensitivity (D10 values) of planktonic, glass- and carrot-associated biofilm cells of Shigella spp. and Aeromonas spp. was determined by forming biofilms on sterile glass and carrot surfaces, incubated at 37 °C ( Shigella spp.) and 30 °C ( Aeromonas spp.) for 48 h. No significant difference in the D10 values of planktonic and glass-associated biofilm cells of Shigella spp. and Aeromonas spp. was observed. However, significant increase in the D10 values of carrot-associated biofilm cells as compared to planktonic and glass-associated biofilm cells of Shigella spp. and A. hydrophila A331 was observed, whereas A. salmonicida Y567 showed insignificant difference. SEM analysis further validated the formation of biofilm on the carrot and glass surfaces. The antimicrobial effectiveness of ionising radiation against both Shigella spp. and Aeromonas spp. is affected by growth form, strain and nature of attachment surface. [ABSTRACT FROM AUTHOR]

We have devised a novel isothermal amplification technology, termed endonuclease restriction-mediated real-time multiple cross displacement amplification (ET-MCDA), which facilitated multiplex, rapid, specific and sensitive detection of nucleic-acid sequences at a constant temperature. The ET-MCDA integrated multiple cross displacement amplification strategy, restriction endonuclease cleavage and real-time fluorescence detection technique. In the ET-MCDA system, the functional cross primer E-CP1 or E-CP2 was constructed by adding a short sequence at the 5' end of CP1 or CP2, respectively, and the new E-CP1 or E-CP2 primer was labeled at the 5' end with a fluorophore and in the middle with a dark quencher. The restriction endonuclease Nb.BsrDI specifically recognized the short sequence and digested the newly synthesized double-stranded terminal sequences (5' end short sequences and their complementary sequences), which released the quenching, resulting on a gain of fluorescence signal. Thus, the ET-MCDA allowed real-time detection of single or multiple targets in only a single reaction, and the positive results were observed in as short as 12 min, detecting down to 3.125 fg of genomic DNA per tube. Moreover, the analytical specificity and the practical application of the ET-MCDA were also successfully evaluated in this study. Here, we provided the details on the novel ET-MCDA technique and expounded the basic ET-MCDA amplification mechanism. [ABSTRACT FROM AUTHOR]

In recent years, the importance of Shigella as an enteric pathogen with global impact has been increasingly recognized. In this study, serogroup distribution of Shigella isolated from clinically diagnosed cases of gastroenteritis and acute diarrhea in Tehran, capital of Iran was investigated between December 2002 and November 2003. Fecal specimens and rectal swabs were cultured for Shigella spp. using standard microbiological techniques. The isolates of Shigella were identified by biochemical assay and serological testing. From a total of 302 Shigella isolates, 178, 110, 10 and 4 strains were identified as S.sonnei (58.9%; 95% CI: 53.2-64.5), S. flexneri (36.4%; 95% CI: 31.0-42.2), S.boydii (3.3%), and S. dysenteriae (1.3%), respectively. The peak of infection occurred during summer. Overall, 167 patients (55.3%) were males and 135 (44.7%) were females

The main objective of this study was to isolate enteric pathogenic bacteria from fishes, Shigella spp., Salmonella spp., Coliform and Streptococci, bacteria that might be transmitted to humans after using and consuming fish. Fish samples were collected during March-October 2013-2014 applying electrofishing method alongside Sitnica, Lepenci and Lumbardhi i Prizrenit rivers. Preparation and isolation of Shigella spp., Salmonella spp., Coliform and Streptococci species from fish samples was realized using standard bacteriological procedures. The isolation of enteric bacteria in fish is an indicator of fecal contamination and/or water pollution. From our analyses we found that the level of presence of such bacteria is within the international standard value of 5.0 x 106 CFU/ml that are already approved by many countries. The lack of Salmonella Spp., Shigella spp., Coliform and Streptococci bacteria on the fecal samples of fish can justify the water purity of these rivers according to microbiological aspect, even though there was presence of sewage waste collector, as well as lower water temperatures of these rivers. Also this results could have been impacted from the presence of heavy metals such as Cadmium (Cd) and Plumb (Pb). It is worth mentioning that they values were a bit higher that allowed standards according to the World Health Organization (WHO). As we know, variability of subtypes of different bacterial aspects reflected for research, risk management, and public health strategies. [ABSTRACT FROM AUTHOR]

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Salmonella spp. and Shigella spp. are known as the leading causes of food poisoning worldwide. In this study, we developed a new multiple fluorescent saltatory rolling circle amplification (MF-SRCA) assay for simultaneous and sensitive detection of Salmonella spp. and Shigella spp. in food based on the generation of real-time fluorescence curves that distinguish the positive from the negative samples. In particular, the MF-SRCA can simultaneously detect two or more targets in one reaction, thus reducing time, reagents, and expenditure, and improving detection efficiency. We showed that MF-SRCA assay was capable of detecting DNA at concentrations as low as 20 fg/μL for each pathogen. Using the MF-SRCA method, the limit of detection (LOD) for Salmonella spp. and Shigella spp. was 10 CFU/mL in artificially inoculated skimmed milk, which was 100 times lower than the LOD of multiple qPCR. Moreover, the MF-SRCA assay was shown to reliably and effectively detect Salmonella spp. and Shigella spp. in 62 samples with higher positive detection rates (9.7% and 6.5%), compared with multiple qPCR (8.0% and 4.8%) and the national standard method (6.5% and 3.2%), respectively. Therefore, this MF-SRCA assay provides an accurate, reliable and cost-effective alternative method for simultaneous detection of multiple microorganisms in food. • ►A MF-SRCA assay was developed for simultaneous detection of Salmonella and Shigella. • ►The MF-SRCA assay offers higher sensitivity and lower LOD than multiple qPCR. • ►The positive detection rate is superior to conventional culture methods. • ►This is a convenient and cheap method for detection of multiple pathogens in food. [ABSTRACT FROM AUTHOR]

Background and Objectives: The emergence of extended-spectrum β-lactamase (ESBL)-producing Shigella spp. is of increasing clinical concern specially in children worldwide. The aim of this study was to investigate the occurrence of extended-spectrum β-lactamase producing Shigella spp. in Tehran, Iran. Materials and Methods: The study included all Shigella isolates recovered from pediatric patients aged less than 12 years admitted to a major pediatric hospital in Tehran, Iran, from 2008 to 2010. Bacterial identification, antimicrobial susceptibility testing, extended spectrum β-lactamases (ESBLs) screening and confirmatory tests were performed according to the standard guidelines. Conjugal transfer experiments and plasmid analysis were also carried out. Polymerase chain reaction and sequencing were used to identify the genetic determinants responsible for ESBL production. Results: Four out of 55 Shigella isolates, including three S. sonnei and one S. flexneri, showed an ESBL-positive phenotype. Plasmid transfer of the ESBL phenotype was successful for the S. flexneri isolate only. By PCR and sequencing, one S. sonnei isolate tested positive for the CMY-59 gene, while the other two S. sonnei and the S. flexneri isolates tested positive for the bla CTX-M-15 genes. Conclusion: We found the prevalence of ESBL producing Shigella isolates was higher than detection rates observed in many other countries. Our finding raise concerns about the dissemination of ESBL among the strains of endemic S. sonnei throughout the country, because this species is now the most frequently isolated Shigella species in Iran and shigellosis by such strains in the community can pose a significant threat to patients and presents a challenge for disease management.

Abstract: Southern Israel is inhabited by Bedouins, living in conditions similar to developing countries and Jews, living in conditions similar to developed countries. We determined the epidemiology of Shigella spp. in these populations. We retrospectively reviewed Shigella spp. stool isolations between 2005–2009. Overall, 3295 isolates were analyzed. S. sonnei was isolated in 2057/3295 (62.4%) and S. flexneri in 1058 (32.1%). S. sonnei was isolated in 1567/1707 (91.8%) from Jewish patients and S. flexneri in 931/1542 (60.4%) from Bedouin patients. Ampicillin resistance increased linearly from 217/373 (58.2%) in 2005 to 186/256 (72.7%) in 2009, (P < 0.001). Trimethoprim-sulfamethoxazole resistance decreased linearly from 328/373 (87.9%) in 2005 to 133/256 (51.9%) in 2009 (P < 0.001). Higher resistance of Shigella spp. to ampicilin and trimethoprim-sulfamethoxazole were found in Jewish patients: 1527/1706 (89.5%) versus 977/1542 (63.4%) (P < 0.0001), 1635/1706 (95.8%) versus 1026/1542 (66.5%) (P < 0.0001). The epidemiology of Shigella spp. infections can differ in populations residing in the same geographical area. [Copyright &y& Elsevier]

Background: Shigellosis is a global human health problem causing an important morbidity among travellers returning from tropical areas. This study was aimed to describe the evolution of antimicrobial resistance profile in Shigella spp. isolated between the years 1995-2010 in patients with traveller's diarrhoea (TD) returning from tropical areas. Methods: The levels of antimicrobial resistance were tested in a total of 191 Shigella spp. isolated during the period from 1995 to 2010. Results: A decrease of cases of diarrhoea caused by Shigella has been observed in recent years. A wide spectrum of antibiotic resistance was observed among Shigella spp. These isolates showed high levels of resistance to tetracycline (84%), co-trimoxazole (75.5%), and ampicillin (45.5%). The resistance was low to ciprofloxacin (2.1%), azithromycin (3.9%) and furazolidone (8.4%). According to the period, in the case of ampicillin, amoxicillin plus clavulanic acid, chloramphenicol, values of resistance were significantly decreasing from 1995 -2000 to 2001-2010, (62.5% vs. 28.4%, 19.8% vs. 6.6%, 23.4 vs. 10.4%, respectively). Meanwhile in nalidixic acid and tetracycline the evolution of resistance has increased over time. Conclusions: A decrease in the isolation number of Shigella spp. causing TD has been observed. Differential trends in the evolution of the levels of resistance to the tested antibacterial agents have been observed. [ABSTRACT FROM AUTHOR]

Background and Objectives: The emergence of extended-spectrum β-lactamase (ESBL)-producing Shigella spp. is of increasing clinical concern specially in children worldwide. The aim of this study was to investigate the occurrence of extended-spectrum β-lactamase producing Shigella spp. in Tehran, Iran. Materials and Methods: The study included all Shigella isolates recovered from pediatric patients aged less than 12 years admitted to a major pediatric hospital in Tehran, Iran, from 2008 to 2010. Bacterial identification, antimicrobial susceptibility testing, extended spectrum β-lactamases (ESBLs) screening and confirmatory tests were performed according to the standard guidelines. Conjugal transfer experiments and plasmid analysis were also carried out. Polymerase chain reaction and sequencing were used to identify the genetic determinants responsible for ESBL production. Results: Four out of 55 Shigella isolates, including three S. sonnei and one S. flexneri, showed an ESBL-positive phenotype. Plasmid transfer of the ESBL phenotype was successful for the S. flexneri isolate only. By PCR and sequencing, one S. sonnei isolate tested positive for the CMY-59 gene, while the other two S. sonnei and the S. flexneri isolates tested positive for the blaTEM-1 and blaCTX-M-15 genes. Conclusion: We found the prevalence of ESBL producing Shigella isolates was higher than detection rates observed in many other countries. Our finding raise concerns about the dissemination of ESBL among the strains of endemic S. sonnei throughout the country, because this species is now the most frequently isolated Shigella species in Iran and shigellosis by such strains in the community can pose a significant threat to patients and presents a challenge for disease management. [ABSTRACT FROM AUTHOR]

Among 5938 clinical Shigella spp. isolates, two S. flexneri strains were isolated as those resistant to fluoroquinolones based on the MICs of the following antibiotics: ciprofloxacin, norfloxacin, ofloxacin, sparfloxacin and levofloxacin. S. flexneri 021787 had three substitutions, one in GyrA (Ser83Leu) and two in ParC (Ser80Ile and Arg91Gln). S. flexneri 021895 had four substitutions, two in GyrA (Ser83Leu and Asp87Gly) and two in ParC (Ser80Ile and Arg91Gln). The increased susceptibility of S. flexneri 021787 and S. flexneri 021895 to ciprofloxacin, norfloxacin and ofloxacin in the presence of the uncoupler carbonyl cyamide- m-chlorophenyldrazone implied that energy-dependent active efflux pumps contributed to the resistance against fluoroquinolones. Both S. flexneri 021787 and S. flexneri 021895 were also induced to express tolC (encoding a resistance–nodulation–division transporter), mdfA (encoding a major facilitator superfamily transporter), and ydhE (encoding a multidrug and toxic compound extrusion transporter) in the presence of ciprofloxacin. Thus, these results indicated that chromosome-mediated fluoroquinolone resistance of S. flexneri 021787 and S. flexneri 021895 resulted from the combination of target site mutations and enhanced expression of genes encoding efflux pumps. [ABSTRACT FROM AUTHOR]

In India, the street food trade is a growing sector with its expansion linked with urbanisation and the need of urban populations for both employment and food. However, the microbiological status of popularly consumed raw street foods, general hygienic and vending practices are not known. We visited 75 vendors (50 having fixed stalls and 25 with mobile stalls) operating in three major locations: mandi (open market place), bus terminus and railway station in New Delhi and Patiala City. A total of 150 samples each of coriander sauce, of ready-to-eat salads and coconut slices collected were analysed for Staphylococcus aureus and Shigella spp. Enterotoxigenic Staphylococcus aureus were detected in 91 (60%) samples of coriander sauce, 87 (58%) samples of coconut slices and 129 (86%) samples of ready-to-eat salads. Twenty-three (15%) samples of coconut slices contained Shigella (18 Sh. dysenteraie type 1 and 5 Sh. flexneri 2a), 13 (8%) samples of ready-to-eat salads and 10 (6%) samples of coriander sauce contained Sh. flexneri 2a. Street vendors lacked access to potable water, toilet facilities and operated under poor hygiene conditions. The results of our study suggest that street vended coconut slices, coriander sauce and ready-to-eat salads could be important potential vehicles for food-borne diseases. [ABSTRACT FROM AUTHOR]

Background: Diarrhoea remains one of the leading causes of childhood mortality globally. Recent epidemiological studies conducted in low-middle income countries (LMICs) identified Shigella spp. as the first and second most predominant agent of dysentery and moderate diarrhoea, respectively. Antimicrobial therapy is often necessary for Shigella infections; however, we are reaching a crisis point with efficacious antimicrobials. The rapid emergence of resistance against existing antimicrobials in Shigella spp. poses a serious global health problem., Methods: Aiming to identify alternative antimicrobial chemicals with activity against antimicrobial resistant Shigella , we initiated a collaborative academia-industry drug discovery project, applying high-throughput phenotypic screening across broad chemical diversity and followed a lead compound through in vitro and in vivo characterisation., Results: We identified several known antimicrobial compound classes with antibacterial activity against Shigella . These compounds included the oral carbapenem Tebipenem, which was found to be highly potent against broadly susceptible Shigella and contemporary MDR variants for which we perform detailed pre-clinical testing. Additional in vitro screening demonstrated that Tebipenem had activity against a wide range of other non- Shigella enteric bacteria. Cognisant of the risk for the development of resistance against monotherapy, we identified synergistic behaviour of two different drug combinations incorporating Tebipenem. We found the orally bioavailable prodrug (Tebipenem pivoxil) had ideal pharmacokinetic properties for treating enteric pathogens and was effective in clearing the gut of infecting organisms when administered to Shigella -infected mice and gnotobiotic piglets., Conclusions: Our data highlight the emerging antimicrobial resistance crisis and shows that Tebipenem pivoxil (licenced for paediatric respiratory tract infections in Japan) should be accelerated into human trials and could be repurposed as an effective treatment for severe diarrhoea caused by MDR Shigella and other enteric pathogens in LMICs., Funding: Tres Cantos Open Lab Foundation (projects TC239 and TC246), the Bill and Melinda Gates Foundation (grant OPP1172483) and Wellcome (215515/Z/19/Z)., Competing Interests: EF, PV, DW, BU, AC, AP, NT, PC, AG, BS, SA, SB is affiliated with GSK Global Health. The author has no other competing interests to declare, Cd, TH, MM, SS, DD, Jd, PP, JW, MM, TS, LB No competing interests declared, (© 2022, Fernández Álvaro et al.)