Shigella Phages Isolated during a Dysentery Outbreak Reveal Uncommon Structures and Broad Species Diversity.

In 2016, Michigan experienced the largest outbreak of shigellosis, a type of bacillary dysentery caused by Shigella spp., since 1988. Following this outbreak, we isolated 16 novel Shigella-infecting bacteriophages (viruses that infect bacteria) from environmental water sources. Most well-known bacteriophages infect the common laboratory species Escherichia coli and Salmonella enterica, and these phages have built the foundation of molecular and bacteriophage biology. Until now, comparatively few bacteriophages were known to infect Shigella spp., which are close relatives of E. coli We present a comprehensive analysis of these phages' host ranges, genomes, and structures, revealing genome sizes and capsid properties that are shared by very few previously described phages. After sequencing, a majority of the Shigella phages were found to have genomes of an uncommon size, shared by only 2% of all reported phage genomes. To investigate the structural implications of this unusual genome size, we used cryo-electron microscopy to resolve their capsid structures. We determined that these bacteriophage capsids have similarly uncommon geometry. Only two other viruses with this capsid structure have been described. Since most well-known bacteriophages infect Escherichia or Salmonella, our understanding of bacteriophages has been limited to a subset of well-described systems. Continuing to isolate phages using nontraditional strains of bacteria can fill gaps that currently exist in bacteriophage biology. In addition, the prevalence of Shigella phages during a shigellosis outbreak may suggest a potential impact of human health epidemics on local microbial communities.IMPORTANCEShigella spp. bacteria are causative agents of dysentery and affect more than 164 million people worldwide every year. Despite the need to combat antibiotic-resistant Shigella strains, relatively few Shigella-infecting bacteriophages have been described. By specifically looking for Shigella-infecting phages, this work has identified new isolates that (i) may be useful to combat Shigella infections and (ii) fill gaps in our knowledge of bacteriophage biology. The rare qualities of these new isolates emphasize the importance of isolating phages on "nontraditional" laboratory strains of bacteria to more fully understand both the basic biology and diversity of bacteriophages.

What is the overlap between HIV and shigellosis epidemics in England: further evidence of MSM transmission?

BACKGROUND: Evidence suggests that sexual transmission between men has replaced foreign travel as the predominant mode of Shigella transmission in England. However, sexuality and HIV status are not routinely recorded for laboratory-reported Shigella, and the role of HIV in the Shigella epidemic is not well understood. METHODS: The Modular Open Laboratory Information System containing all Shigella cases reported to Public Health England (PHE) and the PHE HIV and AIDS Reporting System holding all adults living with diagnosed HIV in England were matched using a combination of Soundex code, date of birth and gender. RESULTS: From 2004 to 2015, 88 664 patients were living with HIV, and 10 269 Shigella cases were reported in England; 9% (873/10 269) of Shigella cases were diagnosed with HIV, of which 93% (815/873) were in men. Shigella cases without reported travel history were more likely to be living with HIV than those who had travelled (14% (751/5427) vs 3% (134/4854); p<0.01). From 2004 to 2015, the incidence of Shigella in men with HIV rose from 47/100 000 to 226/100 000 (p<0.01) peaking in 2014 at 265/100 000, but remained low in women throughout the study period (0-24/100 000). Among Shigella cases without travel and with HIV, 91% (657/720) were men who have sex with men (MSM). HIV preceded Shigella diagnosis in 86% (610/720), and 65% (237/362) had an undetectable viral load (<50 copies/mL). DISCUSSION: We observed a sustained increase in the national rate of shigellosis in MSM with HIV, who may experience more serious clinical disease. Sexual history, HIV status and STI risk might require sensitive investigation in men presenting with gastroenteritis.

High rates of quinolone-resistant strains of Shigella sonnei in HIV-infected MSM.

PURPOSE: There is increasing evidence that shigellosis is a predominantly sexually transmitted disease among men who have sex with men (MSM) and that infection with the human immunodeficiency virus (HIV) is a risk factor for shigellosis. METHODS: Retrospective analysis of antibiotic resistance profiles of Shigella species isolated from stool specimens of patients presenting with diarrhea from January 2010 to July 2012 in three German outpatient clinics specialized in HIV care. RESULTS: Among 79 cases of Shigella sonnei, 56 occurred in HIV-infected MSM, while 23 were observed in HIV-negative MSM. High resistance rates (>90%) were found for doxycycline, tetracycline, aminoglycosides, all cephalosporins of first and second generations tested, and trimethoprim/sulfamethoxazole. In total, 54% of cases were resistant to ciprofloxacin. Compared to negative subjects, HIV-infected MSM had a significantly higher rate of quinolone resistance. For ciprofloxacin, the resistance rates were 66 versus 24%, respectively (p = 0.0016). Individual resistance patterns did not indicate that this was due to a limited outbreak. Rates of resistance to other antibiotics than quinolones showed no differences between HIV-infected and HIV-negative cases. No resistance was found for carbapenems or newer cephalosporins such as ceftriaxone. CONCLUSIONS: The high rates of S. sonnei isolates resistant to quinolones and other traditional antibiotics are of concern. Innovative prevention efforts are urgently needed. The empirical use of quinolones in HIV-infected patients presenting with S. sonnei infection is no longer recommended.

Representaciones sociales de la shigelosis: calidad de vida e incidencia de la enfermedad en niños y su entorno familiar en La Plata, Buenos Aires / Social representations of shigellosis: quality of life and incidence of the disease in children and their family environment in La Plata, Buenos Aires

INTRODUCCION: La shigelosis representa una de las principales causas de diarrea con sangre en América del Sur.OBJETIVO: Establecer la incidencia de shigelosis en zonas urbanas, así como el tipo de Shigella y las condiciones de vida asociadas a esta infección.METODOS: Se realizó un análisis cuali-cuantitativo. Se analizaron shigelosis en niños de La Plata (capital de la provincia de Buenos Aires, Argentina) entre enero de 2009 y diciembre de 2010. Los pacientes incluidos fueron niños menores de 15 años ingresados en el servicio de salud pública por diarrea con sangre, en los que se demostró la presencia de Shigella. Las variables seleccionadas fueron la edad del paciente, el tipo de Shigella, el estado socioeconómico de las familias y el acceso a los servicios de alcantarillado y a la red de agua potable.RESULTADOS: 372 pacientes fueron incluidos. Shigella flexneri fue demostrada en el 66,8% de los casos. La incidencia fue de 187 casos/año/100.000 niños menores de 15 años. Los casos se observaron principalmente durante el verano (38,45%) y en la población de hasta 5 años de edad (69,4%). Se observó que el riesgo de shigelosis aumenta 12 veces en aquellos niños que carecen de agua potable (p < 0,00001) y 1,5 veces en la población sin servicio de alcantarillado (p 0,0064). Según el estudio, vivir en el centro de la ciudad protege de la diarrea causada por Shigella, cuyas áreas críticas se identificaron en los suburbios.CONCLUSIONES: La shigelosis presente en las zonas urbanas depende de la calidad de los servicios de agua y alcantarillado. Las políticas destinadas a evitar esfuerzos individuales y a fomentar estrategias comunitarias, para mejorar las redes de servicios públicos, pueden reducir la incidencia de la shigelosis.

INTRODUCTION: Shigellosis represents one of the main causes of bloody diarrhea in SOuth America.OBJECTIVE: To establish the incidence of Shigellosis in urban zones, as well as type of Shigella and living conditions related to the infection.METHODS: A qualitative and quantitative study was performed, analyzing Shigellosis in children of La Plata (capital of the province of Buenos Aires, Argentina) from January 2009 to December 2010. Patients were children younger than 15 years old admitted in public health services with bloody diarrhea, in whom the presence of Shigella was demonstrated. The variables selected were patient age, type of Shigella, family economic statud and access to sewage services and drinking water network.RESULTS: 372 patients were included. Shigella flexneri was found in 66.8% of the cases. The incidence was 187/cases/year/100.000 children younger than 15 years old. The cases were mainly observed during summer (38.45%) and in the population younger than 5 years old (69.4%). The risk of Shigellosis was 12 times higher for children without access to drinking water (p < 0.00001) and 1.5 times higher in the population without sewer service (p 0.0064). According to the study, living in downtown protects from diarrhea caused by Shigella, while hot spot areas were identified in the suburbs.CONCLUSIONS: Shigellosis in urban areas depends on quality of water and sewer services. The policies aimed at preventing individual efforts and encouraging community strategies to improve public utility networks can reduce the incidence of Shigellosis.

Representaciones sociales de la shigelosis: calidad de vida e incidencia de la enfermedad en niños y su entorno familiar en La Plata, Buenos Aires / Social representations of shigellosis: quality of life and incidence of the disease in children and their family environment in La Plata, Buenos Aires

INTRODUCCION: La shigelosis representa una de las principales causas de diarrea con sangre en América del Sur.OBJETIVO: Establecer la incidencia de shigelosis en zonas urbanas, así como el tipo de Shigella y las condiciones de vida asociadas a esta infección.METODOS: Se realizó un análisis cuali-cuantitativo. Se analizaron shigelosis en niños de La Plata (capital de la provincia de Buenos Aires, Argentina) entre enero de 2009 y diciembre de 2010. Los pacientes incluidos fueron niños menores de 15 años ingresados en el servicio de salud pública por diarrea con sangre, en los que se demostró la presencia de Shigella. Las variables seleccionadas fueron la edad del paciente, el tipo de Shigella, el estado socioeconómico de las familias y el acceso a los servicios de alcantarillado y a la red de agua potable.RESULTADOS: 372 pacientes fueron incluidos. Shigella flexneri fue demostrada en el 66,8% de los casos. La incidencia fue de 187 casos/año/100.000 niños menores de 15 años. Los casos se observaron principalmente durante el verano (38,45%) y en la población de hasta 5 años de edad (69,4%). Se observó que el riesgo de shigelosis aumenta 12 veces en aquellos niños que carecen de agua potable (p < 0,00001) y 1,5 veces en la población sin servicio de alcantarillado (p 0,0064). Según el estudio, vivir en el centro de la ciudad protege de la diarrea causada por Shigella, cuyas áreas críticas se identificaron en los suburbios.CONCLUSIONES: La shigelosis presente en las zonas urbanas depende de la calidad de los servicios de agua y alcantarillado. Las políticas destinadas a evitar esfuerzos individuales y a fomentar estrategias comunitarias, para mejorar las redes de servicios públicos, pueden reducir la incidencia de la shigelosis.

INTRODUCTION: Shigellosis represents one of the main causes of bloody diarrhea in SOuth America.OBJECTIVE: To establish the incidence of Shigellosis in urban zones, as well as type of Shigella and living conditions related to the infection.METHODS: A qualitative and quantitative study was performed, analyzing Shigellosis in children of La Plata (capital of the province of Buenos Aires, Argentina) from January 2009 to December 2010. Patients were children younger than 15 years old admitted in public health services with bloody diarrhea, in whom the presence of Shigella was demonstrated. The variables selected were patient age, type of Shigella, family economic statud and access to sewage services and drinking water network.RESULTS: 372 patients were included. Shigella flexneri was found in 66.8% of the cases. The incidence was 187/cases/year/100.000 children younger than 15 years old. The cases were mainly observed during summer (38.45%) and in the population younger than 5 years old (69.4%). The risk of Shigellosis was 12 times higher for children without access to drinking water (p < 0.00001) and 1.5 times higher in the population without sewer service (p 0.0064). According to the study, living in downtown protects from diarrhea caused by Shigella, while hot spot areas were identified in the suburbs.CONCLUSIONS: Shigellosis in urban areas depends on quality of water and sewer services. The policies aimed at preventing individual efforts and encouraging community strategies to improve public utility networks can reduce the incidence of Shigellosis.

Conformational changes in IpaD from Shigella flexneri upon binding bile salts provide insight into the second step of type III secretion.

Shigella flexneri uses its type III secretion apparatus (TTSA) to inject host-altering proteins into targeted eukaryotic cells. The TTSA is composed of a basal body and an exposed needle with invasion plasmid antigen D (IpaD) forming a tip complex that controls secretion. The bile salt deoxycholate (DOC) stimulates recruitment of the translocator protein IpaB into the maturing TTSA needle tip complex. This process appears to be triggered by a direct interaction between DOC and IpaD. Fluorescence spectroscopy and NMR spectroscopy are used here to confirm the DOC-IpaD interaction and to reveal that IpaD conformational changes upon DOC binding trigger the appearance of IpaB at the needle tip. Förster resonance energy transfer between specific sites on IpaD was used here to identify changes in distances between IpaD domains as a result of DOC binding. To further explore the effects of DOC binding on IpaD structure, NMR chemical shift mapping was employed. The environments of residues within the proposed DOC binding site and additional residues within the "distal" globular domain were perturbed upon DOC binding, further indicating that conformational changes occur within IpaD upon DOC binding. These events are proposed to be responsible for the recruitment of IpaB at the TTSA needle tip. Mutation analyses combined with additional spectroscopic analyses confirm that conformational changes in IpaD induced by DOC binding contribute to the recruitment of IpaB to the S. flexneri TTSA needle tip. These findings lay the foundation for determining how environmental factors promote TTSA needle tip maturation prior to host cell contact.

Shigella dysenteriae type 1-specific bacteriophage from environmental waters in Bangladesh.

Shigella dysenteriae type 1 is the causative agent of the most severe form of bacillary dysentery, which occurs as epidemics in many developing countries. We isolated a bacteriophage from surface water samples from Bangladesh that specifically lyses strains of S. dysenteriae type 1. This phage, designated SF-9, belongs to the Podoviridae family and has a 41-kb double-stranded DNA genome. Further screening of water samples for the prevalence of the phage revealed 9 of 71 (12.6%) water samples which were positive for the phage. These water samples were also positive in PCR assays for one or more S. dysenteriae type 1-specific genes, including ipaBCD and stx1, and live S. dysenteriae type 1 was isolated from three phage-positive samples. The results of this study suggest that phage SF-9 may have epidemiological applications in tracing the presence of S. dysenteriae type 1 in environmental waters.

The molecular epidemiology of trimethoprim-sulphamethoxazole- resistance of Shigella flexneri in the Trakya region of Turkey.

Trimethoprim-sulphamethoxazole (SXT) resistance increased among Shigella flexneri isolates in 1995 relative to previous years, in the Trakya region, the European part of Turkey. Since this region is the entrance to Turkey from northern countries, a heavy traffic of travellers passing through should have been importing or exporting the resistant isolates. We studied the genetic basis and epidemiology of this resistance and monitored the clonal changes which have taken place in the meanwhile. During the study period, a total of 70 Shigella spp. were isolated. Of these 58 were S. flexneri, 10 were S. sonnei and two were S. boydii. S. dysenteriae was not isolated. Of S. flexneri isolates 32 were SXT, ampicillin, chloramphenicol and tetracycline resistant (pattern I), while two isolates were found to be resistant only to SXT (Pattern II). Transconjugation experiments revealed that an approximately 80 Kbp self-transmissible plasmid carried the SXT resistance genes in both groups. However, EcoRI and HindIII restriction patterns of the plasmids from resistance pattern I and resistance pattern II were different. Ribotypes of three randomly selected isolates from pattern I were identical and were distinguishable from the ribotype of the isolate from pattern II. We concluded that at least two different clones with different plasmids and resistance patterns were spreading in our territory.