A Brief History of Shigella.

The history of Shigella, the causative agent of bacillary dysentery, is a long and fascinating one. This brief historical account starts with descriptions of the disease and its impact on human health from ancient time to the present. Our story of the bacterium starts just before the identification of the dysentery bacillus by Kiyoshi Shiga in 1898 and follows the scientific discoveries and principal scientists who contributed to the elucidation of Shigella pathogenesis in the first 100 years. Over the past century, Shigella has proved to be an outstanding model of an invasive bacterial pathogen and has served as a paradigm for the study of other bacterial pathogens. In addition to invasion of epithelial cells, some of those shared virulence traits include toxin production, multiple-antibiotic resistance, virulence genes encoded on plasmids and bacteriophages, global regulation of virulence genes, pathogenicity islands, intracellular motility, remodeling of host cytoskeleton, inflammation/polymorphonuclear leukocyte signaling, apoptosis induction/inhibition, and "black holes" and antivirulence genes. While there is still much to learn from studying Shigella pathogenesis, what we have learned so far has also contributed greatly to our broader understanding of bacterial pathogenesis.

The class II phosphatidylinositol 3-phosphate kinase PIK3C2A promotes Shigella flexneri dissemination through formation of vacuole-like protrusions.

Intracellular pathogens such as Shigella flexneri and Listeria monocytogenes achieve dissemination in the intestinal epithelium by displaying actin-based motility in the cytosol of infected cells. As they reach the cell periphery, motile bacteria form plasma membrane protrusions that resolve into vacuoles in adjacent cells, through a poorly understood mechanism. Here, we report on the role of the class II phosphatidylinositol 3-phosphate kinase PIK3C2A in S. flexneri dissemination. Time-lapse microscopy revealed that PIK3C2A was required for the resolution of protrusions into vacuoles through the formation of an intermediate membrane-bound compartment that we refer to as a vacuole-like protrusion (VLP). Genetic rescue of PIK3C2A depletion with RNA interference (RNAi)-resistant cDNA constructs demonstrated that VLP formation required the activity of PIK3C2A in primary infected cells. PIK3C2A expression was required for production of phosphatidylinositol 3-phosphate [PtdIns(3)P] at the plasma membrane surrounding protrusions. PtdIns(3)P production was not observed in the protrusions formed by L. monocytogenes, whose dissemination did not rely on PIK3C2A. PIK3C2A-mediated PtdIns(3)P production in S. flexneri protrusions was regulated by host cell tyrosine kinase signaling and relied on the integrity of the S. flexneri type 3 secretion system (T3SS). We suggest a model of S. flexneri dissemination in which the formation of VLPs is mediated by the PIK3C2A-dependent production of the signaling lipid PtdIns(3)P in the protrusion membrane, which relies on the T3SS-dependent activation of tyrosine kinase signaling in protrusions.

Bacillary dysentery and meteorological factors in northeastern China: a historical review based on classification and regression trees.

The relationship between the incidence of bacillary dysentery and meteorological factors was investigated. Data on bacillary dysentery incidence in Shenyang from 1990 to 1996 were obtained from Liaoning Provincial Center for Disease Control and Prevention, and meteorological data such as atmospheric pressure, air temperature, precipitation, evaporation, wind speed, and the amount of solar radiation were obtained from Shenyang Meteorological Bureau. Kendall and Spearman correlations were used to analyze the relationship between bacillary dysentery and meteorological factors. The incidence of bacillary dysentery was treated as a response variable, and meteorological factors were treated as predictable variables. Software R 2.3.1 was used to execute the classification and regression trees (CART). The model improved the accuracy of the fitting results. The residual sum square error of the regression tree model was 53.9, while the residual sum square error of the multivariate linear regression model was 107.2. Among all the meteorological indexes, relative humidity, minimum temperature, and pressure one month prior were statistically influential factors in the multivariate regression tree model. CART may be a useful tool for dealing with heterogeneous data, as it can serve as a decision support tool and is notable for its simplicity and ease.

[Incidence of intestinal pathogens in asylum applicants]. / Zum Vorkommen von intestinalen Krankheitserregern bei Asylbewerbern.

UNLABELLED: In Mecklenburg-Vorpommern the Provincial Government has decreed that the laboratory diagnostic examination of applicants for asylum is limited to Salmonella and Shigella. A comprehensive bacteriological and parasitological investigation of 517 applicants for asylum showed a wide pattern of intestinal pathogens. 123 person (23.79%) were infected with pathogenic or facultative pathogenic agents. Regional differences of the extent of distribution and the risks of infestation with pathogens by importation are discussed. CONCLUSION: Limitation of obligatory microbiologic examination to Salmonella and Shigella only is insufficient.

Vacunación contra la shigelosis / Vaccination against shigelosis

Se define como shigelosis a la enfermedad intestinal producida por las diferentes especies del género Shigella, de las cuales el humano es el principal hospedero. Shigella es un bacilo corto, Gram-negativo, de la familia Enterobacteriaceae. La shigelosis se manifiesta en tres formas: 1) disentería clásica (sangre, moco, pus), 2) diarrea acuosa no complicada y 3) una combinación de disentería y diarrea acuosa. La mayoría de los casos de diarrea acuosa no son distinguibles de las que son ocacionadas por otras etiologías. Concluye el documento enfatizando que, no existe hasta el momento actual ninguna vacuna contra Shigella que pueda ser recomendable para la aplicación en población general. Todos los esfuerzos hasta ahora realizados han quedado en pequeños estudios en voluntarios, en los cuales se han obtenido fracasos y en otros ensayos se han vislumbrado posibles vacunas para emplear en el futuro. Dentro de los modelos experimentales de vacunas que hasta el momento hay, se está intentando corregir los posibles errores y por otra parte conjuntar los mecanismos de acción propuestos para cada tipo de vacuna. Finalmente si la shigelosis es un problema de salud pública, principalmente en los países en vías de desarrollo, son importantes los esfuerzos para lograr obtener una vacuna que en lo futuro pueda reducir uno de los principales problemas de morbilidad infantil

Enteric diseases of homosexual men.

Certain enteric ailments are particularly common among homosexual men. They are primarily infectious diseases and include not only such common venereal diseases as gonorrhea and syphilis but also infections not usually regarded as being sexually transmitted. Among the latter are shigellosis, salmonellosis, giardiasis, and amebiasis. Patients' symptoms are non-specific and seldom helpful in diagnosing particular diseases. The practitioner must be prepared to identify a number of infections with similar presentations that may occur singly or together in gay men. Gonorrhea is probably the most common bacterial infection in gay men. Carriage rates as high as 50% have been reported, and extra-genital carriage is common; this necessitates culturing the urethra, rectum, and pharynx. Procaine penicillin G is the treatment of choice for most patients; spectinomycin is probably the drug of choice in penicillin-sensitive patients. In contrast to other venereal diseases, syphilis may have a characteristic protoscopic presentation. Benzathine penicillin G is the treatment of choice for most patients. Lymphogranuloma venereum causes penile lesions and inguinal lymphadenitis in heterosexual men, whereas homosexual men are more prone to proctitis. The disease may mimic Crohn's disease. Recommended treatment includes tetracycline or sulfamethoxazole-trimethoprim. Shigellosis usually presents as an acute diarrheal illness. Patients generally require only supportive treatment with fluids. Herpes simplex viral infection is difficult to diagnose and has several different presentations, including lumbosacral radiculomyelopathy. Symptomatic treatment with sitz baths, anesthetic ointment, and analgesics is recommended. Venereal warts are believed to be caused by the same virus that causes verrucous warts; they are usually found in the anal canal or around the anal orifice. They are commonly treated with 25% podophyllin solution. Parasitic infections include giardiasis, amebiasis, and pinworm infections. Metronidazole may be used in the treatment of symptomatic giardiasis and amebiasis, but it is not approved for the former indication; quinacrine is approved for giardiasis. Pinworm infestation may be treated with pyrantel pamoate or mebendazole. Cure of enteric diseases in homosexual men must be documented.