Use of coagglutination for serotyping Shigella dysenteriae and Shigella boydii

The coagglutination test was used to identify Shigella boydii and Shigella dysenteriae. A trial was carried out with 13 native rabbit antisera to S. boydii and 10 antisera to S. dysenteriae, as well as with coagglutinating reagents prepared from these antisera. The use of coagglutinating reagents was shown to ensure the complete specificity of the results, to prevent the adsorption of diagnostic antisera and to decrease their consumption 50 times. The importance of the coagglutination test for the identification of shigellae is discussed.     

Plasmid-mediated bacteriocin production by Shigella flexneri isolated from dysenteric diarrhoea and their transformation into Escherichia coli

AIMS: To determine the production of bacteriocin by Shigella flexneri strains, to relate their production to the presence of dysenteric diarrhoea and to asses the genetic determination of the bacteriocin. METHODS AND RESULTS: One hundred and sixteen strains of Sh. flexneri were isolated from patients with diarrhoea and 49 of them produced bacteriocin active against several Escherichia coli and abacteriocinogenic Sh. flexneri strains. The extrachromosomal DNA isolated from bacteriocinogenic Sh. flexneri strains were used as a substrate to transform E. coli HB-101 cells by means of electroporation. CONCLUSIONS: Only the Sh. flexneri strains isolated from dysenteric diarrhoea produced bacteriocin. It was demonstrated that a plasmid of approx. 3 kb was responsible for the genetic determination of these anti-bacterial substances. Significance and IMPACT OF THE STUDY: A 3-kb plasmid that harboured information for the production of bacteriocin by Sh. flexneri strains was described. The production of this bacteriocin may be related to dysenteric diarrhoea produced by these bacterial strains.     

Tendencies in the epidemic process of dysentery in Ryazan

In shigellosis caused by Sh. sonnei and Sh. flexneri the epidemic process was found to have considerable difference in the tendencies and pace of its development. Shigellosis which dominated in the etiological structure at the period following 1966 was dysentery caused by Sh. sonnei; it showed the tendency towards a decrease in morbidity rate. Dysentery caused by Sh. flexneri was second in respect to the frequency of its occurrence after 1966 and showed the tendency towards increase. The simultaneous circulation of Sh. sonnei and Sh. flexneri, the differences in the epidemiology of these types of shigellosis make it imperative that they be studied separately, taking into ccount their etiological selectivity to the main routes of transmitting the infection.     

Nature of the epidemic process in Sonne and Flexner dysenteries and the causes of its induction

A comparative study of the epidemic process in Sh. sonnei and Sh. flexneri dysentery in different regions of the USSR revealed that the morbidity level of Sh. sonnei dysentery changed simultaneously in the regions under study at intervals of 2-3 years. Sh. flexneri dysentery showed morbidity rises occurring at intervals 6-8 years, and their occurrence did not coincide with the periods of elevated morbidity in Sh. sonnei dysentery. The data obtained in the cohort analysis and in the study of recurrent morbidity suggest that Sh. flexneri dysentery produces more pronounced postinfection immunity than Sh. sonnei dysentery, and the immunological factor probably affects the dynamics of the epidemic of these Shigella infections.     

Manifestations of the cyclic nature of the epidemic process in dysentery

Different forms of dysentery, especially those caused by Sh. sonnei and Sh. flexneri, have been found to differ considerably in their cyclic recurrence. The development cycles of the epidemic processes of dysentery have an objective character, occur in the presence of any tendencies in the morbidity rate, and depend on the natural factors. Thus, the cycles of increase and decrease in morbidity are 3, 6, 9, 12 years for dysentery caused by Sh. sonnei and 6, 7, 8 years for dysentery caused by Sh. flexneri.     

Phage conversion of escherichia and shigella antigens. I. Phage conversion of type I antigen of Sh. flexneri in entrophatogenic E. coli O129]

The authors realized conversion of type I Sh. flexneri in enteropathogenic E. coli O129 with converting moderate phage phi I Sh. flexneri. Phage phi I lysogenized 7.3--42.7% of the cells of antigenic E. coli variant O129 which lost type V antigen; conversion of the type I antigen of Sh. flexneri was revealed in the agglutination and adsorption of agglutinins tests. As a result, E. coli strain was obtained with the O-antigen identical to the O-antigen of Sh. flexneri Ia.     

Phage conversion of the antigens in Escherichiae and Shigellae. 2. Conversion of the somatic antigen in Shigella flexneri with the moderate E. coli 0129 phage]

The authors studied the converting activity of the moderate EF5 phage isolated from the lysogenic E. coli 0129 strain. It was shown that this phage converted the O-antigen with the detection of the type antigen V in the strains of Sh. flexneri of the serological type la and y-variant. The converted cultures contained the type antigen V and were identical by the antigenic properties to one another and the Sh. flexneri of the serological type 5 and E. coli 0129. A conclusion was drawn that phages converting the antigens of Sh. flexneri could be encountered in escherichia and could modify the antigens in Sh. flexneri and escherichia possessing the antigenic factor 3,4.     

Surface components of shigellae involved in adhesion and haemagglutination

Strains of Shigella species were studied for their ability to adhere and agglutinate mammalian erythrocytes. Shigella dysenteriae and Sh. flexneri exhibited haemagglutinating (HA) properties when cultured in Casamino Acids-Yeast Extract (CYE) broth in the presence of 1 mmol 1^-1 calcium chloride, but other shigellae did not show this property under the same culture conditions. Repeated subcultivation of Sh. boydii, Sh. sonnei and HA negative strains of Sh. dysenteriae and Sh. flexneri in CYE broth medium induced adhesive and haemagglutinating properties that were inhibited by sodium periodate. HA activities of Shigella spp. were also inhibited by N -acetylneuraminic acid, α₁-glycoprotein and fetuin, but not by protease. Electron microscopy of Sh. dysenteriae 1, Sh. flexneri 2a, Sh. boydii 12 and Sh. sonnei 1 grown in CYE broth showed the presence of an extracellular slime layer that promoted agglutination of erythrocytes. The slime layer extracted from the cell surface of Shigella spp. showed HA properties, whereas lipopolysaccharide (LPS) obtained from the same strains, except Sh. dysenteriae 1, did not agglutinate erythrocytes. This evidence suggests that the cell surface haemagglutinin is a loosely bound slime layer which is expressed in CYE broth medium.     

Acid tolerance of Shigella sonnei and Shigella flexneri

AIMS: Determination of the behaviour of Shigella sonnei and Sh. flexneri under acid conditions. METHODS AND RESULTS: The growth and survival of Shigella spp. (9 isolates) in acidified Brain Heart Infusion (BHI) (pH 5.0-3.25 with pH intervals of 0.25) was determined after 6, 24 and 30 h incubation at 37 degrees C. Subsequently, survival of shigellae was studied in apple juice and tomato juice stored at 7 degrees C and 22 degrees C for up to 14 days and in strawberries and a fresh fruit salad, kept at 4 degrees C for 4 and 48 h. CONCLUSIONS: The minimum pH for growth in acidified BHI for Sh. flexneri and Sh. sonnei was, respectively, pH 4.75 and pH 4.50. Survival in fruit juices and fresh fruits depended upon their pH, the type of strain and the incubation temperature. Shigella spp. Survived for up to 14 days in tomato juice and apple juice stored at 7 degrees C. The shortest survival time (2-8 d) was observed in apple juice at 22 degrees C. Sh. sonnei but not Sh. flexneri was recovered after 48 h from strawberries and fruit salad kept at 4 degrees C. SIGNIFICANCE AND IMPACT OF THE STUDY: Acid foods, especially if kept at refrigeration temperatures, support survival of Shigella spp. and may cause Shigella food poisoning.     

一株有争议的志贺氏菌的抗原分析与血清型检定

对中国医学细菌保藏管理中心所存,1935年国外分离,国内检定结果不一的一株志贺氏菌51331进行了详细的抗原分析,确定为福氏志贺氏菌X变种。 该菌能与国内外出品的福氏3型特异血清发生交叉凝集的原因,主要是由于上述诊断用血清中交叉反应性抗体尚未吸收纯净,至少没用类似51331这样的菌株参与成品血清检定的缘故。因此,建议在生产福氏3型特异血清时,应用本菌种参与检定以提高制品质量。本菌种作为诊断血清检定时用的菌种是十分有价值的。     

The immunochemistry of Shigella flexneri lipopolysaccharides. A quantitative analysis of their monosaccharide constituents

1. The lipopolysaccharides of a representative selection of Shigella flexneri serotypes all contain the same constituents as Salmonella chemotype VII, namely, aldoheptose phosphate, 3-deoxy-2-oxo-octonate, O-phosphorylethanolamine, d-galactose, d-glucose, N-acetyl-d-glucosamine and l-rhamnose. 2. The presence of all the Salmonella basal sugars in Sh. flexneri lipopolysaccharides is consistent with the view that the latter contain a basal structure or core which is similar to the common basal structure of Salmonella lipopolysaccharides. 3. Although the Sh. flexneri lipopolysaccharides belong to one chemotype, there appear to be quantitative differences in the composition of their O-specific side chains. The repeating units of Sh. flexneri serotypes 1a, 2a, 3a, 4a, and variant X contain d-glucose, N-acetyl-d-glucosamine and l-rhamnose in the proportions 1:1:2 respectively. The analogous repeating units of serotypes 5a and 6 contain an additional mole of d-glucose and d-galactose respectively and that of variant Y 1 mole of d-glucose less.     

Analysis of merodiploid strains of Sh. flexneri that have lost virulence]

Episome F'13 introduced into the genome of a virulent Sh. flexneri strain brought about changes in a number of properties of the recipient strain. The expression of these properties was not connected with the chromosome area allelic to the plasmid genome. These changes seem to be induced by the mobilization of the chromosome genes of E. coli. The loss of virulence in Sh. flexneri strains carrying episome F'13 seemed to be the consequence of two reasons: the overlapping of kcpA gene by its dominant avirulent allele and abnormal synthesis of cell wall lipopolysaccharide due to the transfer of the mobilized genes from the donor strain F'13. When the preliminary mapping of genes on the chromomome was made with the use of plasmids, it was found necessary to use F-episomes which had no influence on the changes occurring in the phenotypic characteristics of the recipient.     

痢疾杆菌不同群、型间交叉保护性试验研究

本文对痢疾杆菌不同群、型间的交叉保护作用进行了观察。试验模型为恒河猴,将其分为４组,第一、三组分别为感染过福氏１ａ和宋内菌并已康复的猴;第四组为用双价菌苗株ＦＳ（福氏２ａ和宋内）免疫的猴体,剂量依次为４×１０１０、６．５×１０１０、６×１０１０,共１６．５×１０１０活菌,第二组为空白对照。所有４组皆用福氏２ａ２５８００×１０８活菌攻击。从发病率来看,不同菌群与菌型间没有明显的交叉保护作用;从发病程度看则一组显著低于对照组,三组与对照组无显著差异,此结果表明痢疾杆菌Ｂ群内存在交叉保护作用,但较同型保护作用弱。     

Batch process solar disinfection is an efficient means of disinfecting drinking water contaminated with Shigella dysenteriae type I

AIMS: The mortality and morbidity rate caused by Shigella dysenteriae type I infection is increasing in the developing world each year. In this paper, the possibility of using batch process solar disinfection (SODIS) as an effective means of disinfecting drinking water contaminated with Sh. dysenteriae type I is investigated. METHODS: Phosphate-buffered saline contaminated with Sh. dysenteriae type I was exposed to simulated solar conditions and the inactivation kinetics of this organism was compared with that of Sh. flexneri, Vibrio cholerae and Salmonella typhimurium. SIGNIFICANCE: Recovery of injured Sh. dysenteriae type I may be improved by plating on medium supplemented with catalase or pyruvate. Sh. dysenteriae type I is very sensitive to batch process SODIS and is easily inactivated even during overcast conditions. Batch process SODIS is an appropriate intervention for use in developing countries during Sh. dysenteriae type I epidemics.     

The modulation of hela cells secretory patterns by invasive Shigella spp. and enteroinvasive E. coli bacterial cells and their soluble components

Considering the important role of cytokines in the initiation and evolution of the inflammatory process induced by Shigella and EIEC strains, the purpose of this study was the characterization of the secretory patterns of HeLa cells induced by Shigella ssp. and EIEC strains and to link the obtained results with the invasiveness level of bacterial strains on this cellular line. During this study there were analyzed two EIEC strains and 12 strains of the following Shigella species: 2 Sh. flexneri 2a, 2 Sh. flexneri 3a, 2 Sh. flexneri 4a, 2 Sh. boydii, 2 Sh. sonnei strains isolated in Romania during 2005 from children with dysentery and diarrhoea and confirmed for their invasive ability by Sereny test. The level of the main pro and anti-inflammatory cytokines, IL-1 beta, IL-6, IL-10, IL-13, IL-17 and TNF-alpha induced by whole bacterial cultures as well as by their soluble mediators was determined by an ELISA test. Our results showed that HeLa cells can be used not only for the qualitative and quantitative assessment of Shigella and EIEC strains invasion ability, but also as a simple work procedure for the investigation of an in vitro complex crosstalk communication mechanisms that involves physical interactions between bacterial cells and epithelial cells (adhesins and complementary receptors) and pro- and anti-inflammatory molecules regulation.The majority of the analyzed Shigella serogroups, with the exception of Shigella sonnei and EIEC strains, inhibited the inflammatory response by reducing the expression of majority of pro-inflammatory cytokines, i.e., IL-1 beta, IL-6, TNF-alpha and IL-17. The reduced cost of the in vitro procedure, the possibility of results interpretation and the strict regulations concerning the use of animals for experimental purposes are the main reasons that support the implementation of such an in vitro test in the research labs.     

Use of data on Shigella contamination and immunity indices for studying the activity of the epidemic process in dysentery

The comparative study of the monthly distribution of characteristics indicating the levels of contamination with Sh. sonnei and Sh. flexneri separately, as well as the seasonal dynamics of the corresponding antibodies, in the years with high and low morbidity levels has been made with the use the indirect hemagglutination test. The possibility of using these characteristics for the evaluation of the activity of the epidemic process in dysentery caused by Sh. sonnei is shown.     

Characteristics of the action of the biologically active factor from virulent Shigella flexneri strains in a study on mice and a cell culture]

The authors subjected to further study the biologically active factor revealed by them earlier in the virulent Sh. flexneri cultures by using the genetically bound triad of Sh. flexneri 5a-222 cultures and the corresponding couple of Sh. flexneri 2a-516. There was shown correlation of the strains virulence determined by the keratoconjunctival test, with the presence of genetically-determined production of the biologically active factor detectable in the culture filtrate, which produced toxic action of the continuous cell cultures in the virulen Sh. flexneri strains of different serovars (2a and 5a), and lethal action in intravenous injection to mice. Comparative study of toxicity of the preparations of the endotoxin, free endotoxin, and neurotoxin types showed the biologically active factor to resemble the neurotoxin, differing from it in the toxic action and thermolability. Filtrates of the virulent and genetically characterised avirulent strains differed in the protein and lipids content, this permitting to suggest participation of the protein and lipid complex in the toxic action of the biologically active factor.     

食蟹猴肠道志贺氏菌感染情况的调查

本文对 337只食蟹猴肠道志贺氏菌进行调查 ,其感染率为 1 1 %。对所分离到的 2 7株志贺氏菌进行生化、血清学鉴定 ,分属三个群 ,八种血清型 ,痢疾志贺氏菌、福氏志贺氏菌、宋内氏志贺氏菌所占比例分别为 1 0 8%、86 5%、2 7% ,以福氏志贺氏 2a型居多 ,占 59 5%。对八种志贺氏菌血清型菌株进行药敏试验 ,结果表明 ,不同血清型菌株对同一种抗菌药物的敏感性、耐药性均有差异。提示不同血清型的菌株均可自然感染食蟹猴 ,在治疗时 ,对感染不同血清型志贺氏菌的食蟹猴区别用药 ,以提高治愈率 ,避免因用药不当所造成的经济损失。     

Increase in drug resistance among Shigella dysenteriae,Sh flexneri,and Sh boydii.

Two thousand three hundred and seventy strains of Shigella dysenteriae, Sh flexneri, and Sh boydii isolated in England and Wales from 1974 to 1978 were tested for resistance to 12 antimicrobial drugs. Eighty per cent of strains were resistant to one or more drugs, with sulphonamide resistance occurring most frequently. Resistance to streptomycin, tetracycline, ampicillin, and chloramphenicol increased during the period, as did the incidence of multiple resistance. Most infections due to Sh dysenteriae, Sh flexneri, and Sh boydii are acquired abroad, and the increasing incidence of drug resistance among these organisms contrasts with the decreasing incidence of resistance among the indigenous Sh sonnei. These findings may indicate the need for better control of antibiotic use, particularly in developing countries.     

Media with yeast RNA for isolating Shigella flexneri from feces]

The authors demonstrated a considerable, in comparison with the control, increase of the biomass of Sh. flexneri causative agent, when growing in meat-peptone broth with 1-4 mg of NaRNA, and of the number of colonies in the feces of the patients and of healthy persons artificially contaminated with Sh. flexneri when inoculated in Ploskirev's agar or Endo medium with 4 mg/ml of NaRNA. Using media with NaRNA for laboratory diagnosis of dysentery is recommended.