Search

Le Centre National des Shigella de l'Institut Pasteur de Paris enregistre chaque annee une recrudescence du nombre des souches isolees en France et les shigelloses de l'enfant, souvent diagnostiquees dans les pays europeens de l'Est, sont d'une frequence considerable dans lespays en voie de developpement. Par contre les Shigella ne sont qu'exceptionnellement decelees a l'origine des diarrhees infantiles dans nos services hospitaliers de pediatrie et la rarete des publications francaises semble confirmer leur simple incidence dans notre pays. Nous-memes, de 1963 a 1970, sur 775 diarrhees aigues a colibacilles pathogenes, a salmonelles et a germes indetermines, n'avons isole que 7 diarrhees a Shigella , c'est-a-dire moins de 1% de l'ensemble des diarrhees infectieuses.

130 patients with dysenteric syndrome were treated with Poteseptyl (trimethoprim + Superseptyl), among the 70 (54%) Shigella -positive patients. 70% of the infections were caused by

Thirty-four high-risk children admitted to an institution with endemic Shigella flexneri 2a disease were given either streptomycin-dependent S. flexneri 2a or S. sonnei oral vaccine. Fourteen vaccinees in each group remained under surveillance for more than 12 months and one sonnei vaccinee for more than six months. There was no difference in attack rate for S. flexneri 2a diarrhea between the flexneri and sonnei vaccinees (9/14 vs. 9/15). All cases of symptomatic dysentery occurred within nine months after vaccination; despite clinical immunity thereafter, episodic asymptomatic excretion of shigella was observed in 10 of 28 children. The level of immunity induced by streptomycin-dependent S. flexneri 2a oral vaccine was insufficient to prevent disease in this institutional setting.

Shigellosis is a waterborne disease but detection and isolation of Shigella in the water cannot be credibly ascertained even during epidemics. The detection, persistence or survival of Shigella in water is thus quite imperative to control the disease. The present study attempts to study the survival of Shigella in waters of different sources using Shigella boydii 15 ATCC12034 as reference culture. Five microcosms were set up; these were pond water (from two locations), tap water, distilled water and Phosphate Buffer Saline (PBS). Relatively longer bacterial persistence was found in microcosms with pond water as compared to that observed in microcosms with PBS and distilled water. With the initial inoculums of 10 5 cfu/ml, the strain became nonculturable after 9 and 18 days in PBS and pond water, respectively. But with the inoculum size of 10 6 cfu/ml, it survived up to 16 to 22 weeks in pond waters from two different sources. The morphological and biochemical characteristics of the bacteria remained unchanged over this time. Fluorescent microscopy and PCR were carried out to detect the presence of Shigella boydii 15 in the waters after it became nonculturable in conventional nutrient media. The survival of Shigella in water was possibly inoculum’s size dependent; its presence might diminish with time due to lack of nutrients and shifting of physicochemical factors, etc. in water. Key words: Shigella boydii; Survival; Microcosm; Viable; Nonculturable DOI: http://dx.doi.org/10.3329/dujbs.v19i2.8951 DUJBS 2010; 19(2): 103-110

Arm , H. G. (Naval Medical Research Institute, Bethesda, Md.), T. M. Floyd, J. E. Faber, and J. R. Hayes . Use of ligated segments of rabbit small intestine in experimental shigellosis. J. Bacteriol. 89: 803–809. 1965.—Inoculation of ligated segments of small intestine in living rabbits with broth cultures or resting-cell suspensions of recently isolated strains of Shigella caused distension of the segments by accumulation of exudate within 12 hr. Histological changes characteristic of an inflammatory response were similar to those of human bacillary dysentery. Tissue response and accumulation of exudate preceded demonstrable increase in numbers of shigellae inoculated as 2 × 10 10 resting cells. Capability of shigellae to provoke intestinal response was not related to any particular serological group. The active principles concerned with eliciting intestinal response were associated only with preparations containing living organisms. Ability of recently isolated strains to elicit response diminished rapidly during culture on artificial media. The capability was preserved indefinitely by lyophilization soon after isolation from acute bacillary dysentery infections of man. Advantages of using shigellae recently isolated for investigating possible mechanisms of pathogenesis were indicated. During the summer months, the rabbit small intestine was refractory to the activity of shigellae, and positive responses were not observed. Use of ligated segments of rabbit small intestine qualified as an indicator of virulence for the rabbit; and, virulence for the rabbit showed a high degree of correlation with a short period of culture of shigellae on artificial media after isolation from human bacillary dysentery infections.

A fatal ulcerative colitis-like lesion, occurring in association with socioenviron-mental upheaval, is described in 4 Siamang gibbons. Because these animals resided in zoos, it was possible to rule out shigellosis with any degree of certainty in only 1 of the 4 cases. The clinical picture was compatible with acute Shigella dysentery in the remaining 3 animals, but it was remarkable that none of the cagemates or adjacent animals developed diarrhea, and that the apparent precipitating emotional stress was identical in the 3 animals that died.

Four outbreaks of shigellosis recently occurred aboard a Naval vessel (1). Several shigella carriers were found who were considered to be the source of infection in the last two outbreaks. A study of these carriers (with particular reference to their therapy) was undertaken since they constituted a major problem in eradication of the disease. It is obvious that a large number of persistent shigella carriers can be an epidemiological problem. Manson-Bahr (2) reports an individual who excreted dysentery bacilli for a period of three years. In an excellent review, Neter (3) states that carrier rate surveys have varied from 3–80 per cent and that 3 per cent of convalescent carriers excrete organisms for more than three months after the onset of the disease. Watt et al. (4) studied 57 cases of Shigella flexneri infections. Among this group 45 individuals (79 per cent) became convalescent carriers, in 38 of whom the duration of the carrier state was determined.

In our study of the transferable nature of the multiple resistance of Shigella sonnei strains isolated in the period from 1963 to the end of 1967, it was found that at least 63.1% of the multiply resistant strains possessed the transmissible type of resistance. Contrary to expectation, no continuous increase in the percentage of multiply resistant strains was observed; rather the percentage of resistant strains fluctuated. The highest percentage (12%) was observed in 1961, 1962, 1963. In 1966 the percentage decreased to 1.3% and in 1967 increased again to 4.2%. Until June 1968 no single multiply resistant strain has been isolated. There was a decrease rather than an increase in the number of multiply resistant strains of Shigella sonnei. The authors explain this by the fact that in the period of observation no epidemic of shigellosis occurred.

Summary and Conclusion One hundred Egyptian village children were immunized with 1.0 ml. of a Shigella flexneri 3 vaccine, given in three divided doses of 0.3 ml., 0.3 ml. and 0.4 ml. at weekly intervals. A similar group of unvaccinated children were observed as controls. During a six month observation period following vaccination, 25 (26.8 per cent) of the children who received the vaccine were found to be infected with Shig. flexneri 3 organisms as compared with 18 (20.4 per cent) of the children in the control group. The number of infections with other Shigella organisms, and the number of episodes of diarrheal disease, was approximately the same in both groups of children. Immunization with a Shigella flexneri 3 vaccine was not effective in preventing Shigella flexneri 3 infections, or diarrheal disease associated with these organisms, in a group of Egyptian village children living in a highly endemic environment.

Attempts to define mechanisms of host susceptibility to Shigella infection would be facilitated by the development of a suitable small animal model. The natural resistance of common laboratory animals to experimental infection with shigellae has been overcome by a number of methods. Successful infection of mice and guinea pigs can be accomplished by pretreatment with antibiotics to alter intestinal flora sufficiently to minimize its protective effects [1]. However, such infections are almost invariably asymptomatic and thus are of limited value for the study of natural disease. Fatal Shigella infection can be produced in adult guinea pigs by starvation or subcutaneous injection with carbon tetrachloride, provided that calcium carbonate is given before and opium administered after oral challenge [2, 3]. Germfree guinea pigs are also susceptible to shigellosis [4]. Injection of substances adversely affecting the Krebs cycle prior to oral challenge has been reported to induce fatal infection in mice [5]. Studies in guinea pigs indicate that an essential step in the pathogenesis of shigellosis is penetration of the intestinal mucosa by infecting organisms [6]. Since cellular turnover in the intestinal mucosa operates at an exceedingly rapid rate

A total of 1,819 infants with diarrhea were examined in Panama for the presence of enteropathogenic bacteria. Results of the single rectal-swab cultures from these patients revealed a very low prevalence (7.9%) of all pathogens. Enteropathogenic Escherichia coli accounted for 5.3%, Shigella for 1.7%, and Salmonella for 1.2%. Serotypes of the enteropathogens isolated were determined; E. coli 055:B5 was found in 35.4% of the instances of isolation of E. coli. Enteropathogenic E. coli and Salmonella were isolated from infants with diarrhea only, as well as from infants with diarrhea and other symptoms. On the other hand, Shigella infections were not encountered in infants with diarrhea alone. Shigellosis occurred in the more severely ill infants, in whom other symptoms accompanied the diarrhea. When the diarrheal cases were grouped by severity of symptoms, the highest rate of infection (12%) was found in the dehydrated infants. Isolations were all from acute, sporadic cases throughout Panama City, suggesting that the source of infection was not localized.

In the 10 years 1964-1973, 105,832 isolations of shigellae were reported to the Center for Disease Control through a nationwide surveillance system. The number reported increased by approximately 13% annually, from 5852 in 1964, when only 17 centers reported all 4 quarters; to 16,797 in 1973, when 52 centers reported each quarter. The rate of reported isolations varied from 4.6 per 100,000 persons in 1965 to 9.1 per 100,000 in 1973. Shigella sonnei accounted for 64% of all these isolates and for more than 80% of isolates in 1973. The majority of reported cases of shigellosis occurred in young children and in women of childbearing age. During the 10-year surveillance period, 35 epidemics in 25 states were investigated. Two-thirds of these outbreaks were the result of person-to-person spread; investigations of common-source outbreaks showed the importance of both water and foodstuffs, especially salads, as potential vehicles of contamination. Indian reservations, custodial institutions, and day-care centers were identified as special high-risk settings for the transmission of shigellosis. The emergence of R-factor-mediated antimicrobial-resistance patterns in recent years has necessitated antibiotic sensitivity testing to determine the drug of choice for treatment of individual cases. Initial testing of oral vaccines suggests these vaccines will have only limited usefulness in protecting certain high-risk populations. Public health education coupled with improvements in water and sewerage systems remains the most satisfactory means of control.

Summary The relationship of some general environmental factors to the prevalence of Shigella infections and, more specifically, the effects of the availability of water for washing purposes on shigellosis rates were studied. The areas under observation were divided, either by city blocks, parts of blocks, or premises into groups with similar sanitational features. After each environmental grouping was completed, the infection rates for each of the groups was found. Three conclusions which are applicable to diarrheal disease control were drawn from the results. 1. Areas could be defined by using common sanitational standards to indicate potentials for spread of Shigella organisms. 2. Infection rates of a neighborhood were found to vary with the proportion of poor housing in it. 3. Infection rates were highest where water was least available for personal hygiene. Consequently, availability of water for washing purposes must be considered along with purity of water in any diarrheal disease control program.

Statistics showing the distribution of 1,030 Shigella and Salmonella strains isolated from patients of Cook County Hospital during the period between April, 1948 and March, 1953 were given. The course and the physical findings in 477 of these persons before the diagnosis was established was analyzed.

Extract: An immunologic study was carried out on 140 children with infections of the urinary tract. The diagnosis was based on clinical, roentgenologic, urologic, and bacteriologic findings. Of the patients, 37 (26%) had acute infection and the remainder (103 children, 74%) had chronic or recurrent infection. The hemagglutination test was used to measure the antibody levels against the O antigens of the urinary isolates. The patients were studied for a period of 1–7 years. An antibody response was documented in all but 10.7% of the subjects. Multiple antibody responses occurred in 55% and single antibody responses in 34.3% of the patients. There was no significant difference in the antibody responses to commonly encountered serogroups of Escherichia coli and other bacteria less frequently found in urinary tract infection. In 17 subjects, the antibody titer decreased rapidly within 2–8 weeks, and in 9 subjects reinfection with the microorganisms of identical serogroups led to a recall antibody response. It was shown that in 14 subjects (10%), minimal bacteriuria was accompanied by the production of the corresponding O antibodies, and in an additional 7 subjects (5%), asymptomatic bacteriuria, following or preceding overt infection, led to a specific antibody response. Continued production of O antibodies over many months was observed following overt infection even in the absence of persisting bacteriuria; in other patients, however, even prolonged bacteriuria resulting from identical serogroups was not associated with the production of the corresponding O antibodies. It is suggested that determination of the immune response of patients with urinary tract infection may aid in the identification of the etiologic role of urinary isolates, even when present in small numbers; may document infection by two or more antigenically unrelated microorganisms; and may help in the differentiation of relapse and reinfection. Thus, determination of the immune response may be a useful tool in the elucidation of certain aspects of this frequent, but incompletely understood disease. Speculation: Because infectious agents or their antigens must reach cells of the immune apparatus to elicit an antibody response, documentation of the production of specific antibodies may aid in the differentiation between true infection and urinary contamination, between reinfection and relapse, and in ascertaining the clinical signification of minimal bacteriuria. It may be speculated that since titers of O antibodies decrease substantially a few months after recovery from shigellosis and salmonellosis, persistent elevated antibody titers against O antigens of urinary pathogens are associated with continued antigenic stimulation and may reflect continuation of the pathologic processes.

Formal, Samuel B. (Walter Reed Army Institute of Research, Washington, D.C.), E. H. LaBrec, Amos Palmer, and Stanley Falkow . Protection of monkeys against experimental shigellosis with attenuated vaccines. J. Bacteriol. 90: 63–68. 1965.—Two Shigella flexneri 2a strains of reduced virulence were used as oral vaccines to protect monkeys against experimental challenge. One strain, a spontaneous mutant, had lost its ability to cause disease and was unable to penetrate the intestinal epithelium and reach the lamina propria. The other strain was a hybrid obtained by mating virulent S. flexneri 2a with Escherichia coli . This hybrid strain retained the capacity to penetrate the intestinal epithelium but was not able to maintain itself in the lamina propria. Five oral doses of the nonpenetrating mutant strain were required to render monkeys resistant to experimental challenge, but a single dose of the hybrid strain sufficed to protect the animals. There was some evidence that a degree of specificity was involved in the induced resistance, although neither vaccine evoked a consistent serum antibody or a detectable coproantibody response.

Four attenuated strains of Shigella flexneri 2a have been tested for stability and safety as vaccines in man. One strain, a Shigella-Escherichia coli hybrid, was virulent for man in doses of 108 cells, while a mutant strain reverted to virulence when 1010 cells were administered orally. Two vaccine strains, a Shigella mutantE. coli hybrid and a streptomycin-dependent mutant, were safely given to adult males in doses of 5-10 X 1010 cells. Pretreatment with sodium bicarbonate was essential for the assurance of intestinal transit of viable vaccine organisms, and less than one-third of those vaccinated developed rises in humoral antibody. Streptomycin-independent revertants could be recovered only rarely in vivo when the streptomicin-dependent mutant was used, and one revertant found was avirulent. These studies have outlined the important biologic requirements of potential live oral shigella vaccines. Strains must not penetrate the intestinal mucosa and must be stable without reverting to virulence at levels of dosage used.

Thirty-four high-risk children admitted to an institution with endemic Shigella flexneri 2a disease were given either streptomycin-dependent S. flexneri 2a orS. sonnei oral vaccine. Fourteen vaccinees in each group remained under surveillance for more than 12 months and one sonnei vaccinee for more than six months. There was no difference in attack rate for S. flexneri 2a diarrhea between the flexneri and sonnei vaccinees (9/14 vs. 9115). All cases o f symptomatic dysentery occurred within nine months after vaccination; despite clinical immunity thereafter, episodic asymptomatic excretion o f shigella was observed in 10 of 28 c&Tdren. The level o f immunity induced by streptomycin-dependentS, flexneri 2a oral vaccine was insufficient to prevent disease in this institutional setting.

In the island of Curacao Shigellosis is the most common notifiable contagious disease. The causative agents areSh. paradysenteriae, Sh. sonnei andSh. ambigua. After rainfall epidemic outbreaks may be expected.

Formal, Samuel B. (Walter Reed Army Institute of Research, Washington, D.C.), T. H. Kent, H. C. May, A. Palmer, and E. H. LaBrec . Protection of monkeys against experimental challenge with a living attenuated oral polyvalent dysentery vaccine. J. Bacteriol. 91: 17–22. 1966.—Virulent strains of Shigella flexneri 1b, S. flexneri 3, and S. sonnei I were mated with an Hfr strain of Escherichia coli K-12, and hybrids were selected for the xylose marker. One hybrid strain of each of the serotypes was chosen for study of their biological characteristics. Their capacity to cause a fatal enteric infection in starved guinea pigs was reduced, they failed to cause dysentery when fed to monkeys, they caused keratoconjunctivitis in the guinea pig eye, and they penetrated HeLa cells. Two doses of a polyvalent oral vaccine composed of S. flexneri 1b, 2a, and 3, and S. sonnei I hybrid strains were fed to groups of monkeys at an interval of 4 to 7 days, and they, together with controls, were challenged 10 days after the last dose with one or another of the virulent parent dysentery strains. A significant degree of protection was afforded in all vaccinated groups with the exception of one group challenged with S. flexneri 6, a component not included in the vaccine. When animals were challenged with virulent S. flexneri 2a 1 month after oral vaccination, they were also protected. The vaccine produced a rise in serum antibody, but we were not able to detect coproantibody in saline extracts of feces from animals which received the vaccine.

Summary This preliminary study was designed to determine the prevalence of Salmonella and Shigella in human population groups without reference to the presence or absence of frank diarrheal disease. Twelve communities in Guatemala were selected for study, and children 0–10 years of age examined by means of rectal swabs. Data on the external environment were obtained by observation and by compilation of locally available statistics. The high prevalence rates for Shigella were shown to be comparable with rates obtained in selected specific areas of the United States during periods when Shigella infection was determined to be the major cause of diarrheal disease deaths. Although not all of the diarrheal problems in Guatemala are related to shigellosis, the data strongly suggest that organisms of the genus Shigella cause the major portion of diarrheal diseases in the communities studied in Guatemala and that diarrheal diseases caused by Shigella represent a major public health problem in the country. The high rates in Guatemala, as in the United States, were associated with the lack of sanitary facilities, with poor housing, with limited water supply and with poor personal hygiene.