Strains Of Sh Research Articles

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

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. 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. 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. 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.

Development of a multiplex PCR detection of Salmonella spp. and Shigella spp. in mussels.

Multiplex PCR amplification of invA and virA genes was developed enabling simultaneous detection in mussels of Salmonella spp. and Shigella spp., respectively. Simultaneous amplification of products of 215 and 275 bp was obtained either by using mixtures of individual strains of Sh. dysenteriae and Salm. typhimurium or spiked contaminated mussels with both bacteria. In the case of the mussels, 10-100 cells of Salmonella spp. and Shigella per millilitre of homogenate were detected by the multiplex PCR following a pre-enrichment step to increase sensitivity and to ensure that detection was based on the presence of cultivable bacteria. Also, the sensitivity and specificity of this method was evaluated. Multiplex PCR amplification was shown to be an effective, sensitive and rapid method for the simultaneous detection of pathogens in mussels.

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, alpha 1-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.

Vero cytotoxin production and presence of VT genes in strains ofEscherichia coliandShigella

Strains of enteropathogenic Escherichia coli (EPEC), enteroinvasive E. coli (EIEC) and Shigella were examined for Vero cytotoxin (VT) production and tested for the presence of VT genes in DNA hybridisation experiments with specific probes for VT1 and VT2. Twenty seven of 104 EPEC strains produced VT and in 26 of the 27 strains VT genes were detected. The VT+ EPEC strains belonged to serogroups O26, O55 and O128. Strains belonging to 8 other EPEC serogroups including strains isolated from 13 outbreaks, were all negative using both techniques, as were the 5 EIEC strains. It is concluded that VT1 and VT2 are not virulence factors in most EPEC infections. VT1 was demonstrated in all Sh. dysenteriae type 1 strains but neither VT1 nor VT2 were detected in strains of Sh. flexneri, Sh. boydii or Sh. sonnei.

Vero cytotoxin production and presence of VT genes in strains of Escherichia coli and Shigella

Strains of enteropathogenic Escherichia coli (EPEC), enteroinvasive E. coli (EIEC) and Shigella were examined for Vero cytotoxin (VT) production and tested for the presence of VT genes in DNA hybridisation experiments with specific probes for VT1 and VT2. Twenty seven of 104 EPEC strains produced VT and in 26 of the 27 strains VT genes were detected. The VT+ EPEC strains belonged to serogroups O26, O55 and O128. Strains belonging to 8 other EPEC serogroups including strains isolated from 13 outbreaks, were all negative using both techniques, as were the 5 EIEC strains. It is concluded that VT1 and VT2 are not virulence factors in most EPEC infections. VT1 was demonstrated in all Sh. dysenteriae type 1 strains but neither VT1 nor VT2 were detected in strains of Sh. flexneri, Sh. boydii or Sh. sonnei.

PLASMID CHARACTERISATION IN THE INVESTIGATION OF AN EPIDEMIC CAUSED BY MULTIPLY RESISTANT SHIGELLA DYSENTERIAE TYPE 1 IN CENTRAL AFRICA

A strain of Shigella dysenteriae type 1 resistant to ampicillin, chloramphenicol, streptomycin, sulphonamides, and tetracyclines has caused an epidemic of shiga dysentery in northeast Zaire. Since November, 1979, it has caused many deaths in an extensive area which now includes neighbouring Rwanda. The strain carries a resistance plasmid of compatibility group X, indistuinguishable from the plasmid previously found in strains from Somalia. This contrasts with multiply resistant strains of Sh. dystenteriae type 1 from Central America and South-East Asia in which resistance is determined by plasmids of compatibility group B.

Colicin Typing of Shigella sonnei by Means of Specific Indicator Strains. An Enlarged Scheme

The scheme of colicin typing of Shigella sonnei includes 26 colicin types. Thirty-three indicator strains were used for typing and 22 of them were prepared by conjugational transfer of col factors from shigellae on recipient strain of E. coli K 13 HfrR nal r or E. coli K 12 ROW. Immune strains of Sh. sonnei or resistant mutants of E.coli K 12 ROW were used as indicator strains only sporadically. Zusammenfassung Das Colicin-Typisierungsschema von Sh. sonnei umfaßt 26 Colicintypen. Für die Typisierung wurden 33 Indikatorstämme verwandt, wovon 22 durch Konjugationsübertragung von Col-Faktoren der Shigellen auf Empfängerstämme von E. coli K 13 HfrR nal r oder E.coli K 12 ROW prepariert wurden. Immunstämme von Sh. sonnei oder resistente Mutanten von E. coli K 12 ROW wurden nur vereinzelt als Indikatorstämme verwandt.

Formation of polyprenol monophosphate glucose in Shigella flexneri

An enzyme synthesizing polyprenol monophosphate glucose from UDPglucose is present in the membrane fraction from Shigella flexneri 2a; UDPgalactose can also be used as the sugar donor. GDPmannose, UDPglucuronic acid and UDP-N-acetylglucosamine were ineffective. Triton X-100 or deoxycholate were required for enzymic activity. Ficaprenol (mainly C 55) phosphate was the most effective lipid acceptor of glucose. The phosphate esters of other polyprenols (phytol, betulaprenol, solanesol and dolichol) were much less effective. Lipid extracts from Sh. flexneri did not stimulate the formation of lipid-linked glucose. No polyprenol phosphate phosphatase was detected in membrane preparations from 2a and Y strains of Sh. flexneri.

An epidemiological study of strains of Shigella sonnei from two related outbreaks.

During the winter of 1967-8 Sonne dysentery affected neighbouring North London primary schools. This was not simply due to cross-infection between the two schools, for two different, unusual strains of Sh. sonnei were distinguished. One was a novel kanamycin-resistant colicine type 7 strain, and as far as we know this was the first school outbreak due to such a strain to be documented. The other strain was kanamycin-sensitive and of colicine type 0 with a rare specific requirement for aspartic acid. There was some evidence to suggest that the kanamycin-resistant strain was more infective for adults and possibly more pathogenic than the kanamycin-sensitive.Studies on the transfer of drug resistance and of colicinogeny revealed that the factor determining colicine type 7 was carried on a transmissible plasmid, a new observation. Various drug resistances were also transmissible experimentally, and some were spontaneously unstable. Non-transferable ampicillin-resistance in the colicine type 7 strain and aspartic acid dependence in the colicine type 0 strain enabled all but one of the isolates to be classified into two distinct lines. No common ancestor was found and it was concluded that although occurring together they must have arisen from separate sources.

Emergence of Shigella sonnei resistant to kanamycin and to nalidixic acid, without exposure to these drugs.

Summary Sh. sonnei resistant to kanamycin in one household and, in another family, to nalidixic acid, is described. Resistance of this organism to these drugs is uncommon. Some individuals within each family excreted sensitive strains of the shigella. There was no history of previous exposure to either drug and the source of the resistant strains is unknown. As far as we know these strains neither arose from nor spread to the community. Kanamycin-resistance was determined by a transferable factor; no transfer of nalidixic acid-resistance could be demonstrated. The supplanting of the prevailing sensitive strains by new drug-resistant strains of Sh. sonnei is unexplained in both families.

Further studies on the antibiotic resistance of Shigella sonnei. II. The acquisition of transferable antibiotic resistance in vivo.

A method is described for the testing of strains of Sh. sonnei for antibiotic resistance, colicine type and drug resistance transfer using a multiple inoculator.The examination of 731 strains of Sh. sonnei isolated from convalescent cases and their family contacts showed that about 5% of individuals were excreting organisms which differed from the infecting strain by a single transferable antibiotic resistance determinant. It is suggested that the acquisition of such resistance may occur in 13% of family incidents.

Further studies on the antibiotic resistance of Shigella sonnei. I. Transferable antibiotic resistance.

SummaryThe incidence of antibiotic resistant strains ofSh. sonneiisolated in the London area is described. Strains were tested for their ability to transfer resistance to Most strains were resistant to sulphonamide and this resistance was transferable.An increasing proportion of strains was resistant to 800 µg./ml. of streptomycin, but transferable streptomycin resistance was less common and often associated with tetracycline resistance.The proportion of strains resistant to tetracycline fluctuated but this resistance was always transferred.Ampicillin resistance was common; only those strains resistant to 500µg./ml. transferred this resistance.Resistance to other antibiotics was very rare.

Some studies on the epidemiology of Sonne dysentery. Changes in colicine type and antibiotic resistance between 1956 and 1965.

The colicine type and antibiotic resistance have been determined on strains ofSh. sonneiderived from 9419 incidents of Sonne dysentery in London between October 1956 and March 1965.The most striking observation has been the appearance of strains with patterns of colicine production and antibiotic resistance new to the area. These changes are best regarded as a result of the interaction and transfer of characters betweenSh. sonneiand other intestinal organisms.The general tendency has been for strains ofSh. sonneito become increasingly resistant to antibiotics but this has not been an uninterrupted process. The proportion of drug-resistant strains at any one time depended on the properties of the current epidemic strain.Spread of Sonne dysentery was essentially local, but some strains ofSh. sonneiwere found to spread much more widely than others. Most, but not all, of the strains resistant to streptomycin and tetracycline possessed only limited powers of spreading.

The survival ofShigella sonneion cotton, glass, wood, paper, and metal at various temperatures

1. Ten strains ofSh. sonneiwere placed upon metal, wood, cotton, paper, and glass and held at −20°, 4°, 15°, 37° and 45° C. Survival of the cells was most extensive when placed at −20° C. and practically none of the strains survived when held at 45° C.2. Slight variations in the survival of different strains was observed when the cells were placed upon glass and cotton. Strain variation was greater when survival time was measured by placingSh. sonneion wood, paper, and metal.

細菌代謝に対するオキシンCu, Co錯塩の影響

Using the standard strains of Sh. flexneri and Staphy. aureus taken from the departmental stock, the author studied the effects of oxine, Cu++, Co++, combination of oxine-Cu++ and that of oxine-Co++ on the growth of bacteria and the glucose metabolism during their growth. The following results were obtained.1) The cooperative inhibition of oxine and Cu++ or oxine and Co++ on the growth was revealed most strikingly when oxine and metal ions came near equal concentrations. Of course, it was necessary to be kept both oxine and metal ions are exceeded a certain concentrations for revealing their inhibitory effects.2) The accumulation of pyruvate and lactate in the media was markedly increased in oxine or Co++ added media, on the other hand the accumulation of the metabolites from glucose was decreased in the case of Cu++ added media compaired with control.3) It was found that the metabolite acumulated slightly much in the media added oxine and Cu++ or oxine and Co++ than control media.

Distribution of mucinolytic activity in strains of Shigella.

SummaryA survey was made to determine the incidence of mucinase production among representative strains of the genus Shigella. With the culture conditions employed, 24 out of 27 strains of Sh. flexneri 2a, 1 of 4 cultures of Sh. flexneri X and 2 of 9 strains of Sh. flexneri Y demonstrated mucino-lytic activity while none of the 214 strains of other serological types of dysentery bacilli were found to be active. Immunization of rabbits with a crude enzyme preparation from a strain of Sh. flexneri 2a yielded an antiserum which neutralized its mucinolytic activity.

Antigenic identity of Shigella alkalescens type I and Kauffmann's Escherichia O group 1.

SummaryAgglutination and agglutinin absorption tests performed with fifteen E. coli strains of Kauffmann's O group 1 and nine strains of Sh. alkalescens demonstrated that their O antigens were indistinguishable.

Antigenic Relationship of Shigella dispar, Types I and II, to Shigella paradysenteriae, Boyd Type P143

Attempts to classify certain paradysentery-like bacteria have indicated a possible antigenic relationship between Shigella dispar and Shigella paradysenteriae, type P143.1 In particular, a culture (No. 2-193) isolated by Major William H. Ewing, Sanitary Corps, United States Army, has been classified on various grounds as Sh. Paradysenteriae, type P143,2Sh. Alkalescens,3,4 and Sh. dispar.2 The present investigation was undertaken to attempt to clarify the relationship between Sh. dispar and type P143.Four serotypes and several subtypes of Sh. dispar were previously reported.5 Representative strains of these were employed. Type P143 was secured through the courtesy of Dr. K. M. Wheeler of the Connecticut Public Health Laboratories as his culture No. 573.6 Antiserums were prepared by immunizing rabbits with living vaccines of this and of the type and subtype strains of Sh. dispar.Cross agglutination tests indicated the existence of antigens common to type P143 and Sh. dispar, types I and II. This was confirm...

Antigenic Relationships of the Species Shigella dispar.

Castellani isolated from the feces of patients with clinical dysentery a bacterium which he named “Bacillus ceylonensis B.” Five years later he reported the isolation from normal human stools of Bacillus madampensis. Both organisms were gram-negative, nonmotile rods, fermenting many carbohydrates, including lactose, with production of acid only, and producing indol. Bacillus ceylonensis B fermented dulcitol, whereas Bacillus madampensis did not. Both fermented sucrose. Andrewes included these 2 species, together with some other lactose-fermenting dysentery-like varieties, in his “Bacillus dispar.” Current terminology places these microorganisms in the genus Shigella. Castellani stated that Bacillus ceylonensis B was a serologically homogeneous species. Glynn and Starkey, working with 15 strains, reported Shigella dispar antigenically heterogeneous. The present investigation was undertaken to study further the antigenic structure of strains designated Shigella dispar or Shigella ceylonensis. Thirty-seven strains of bacteria are included in this preliminary report. Five were received from the American Type Culture Collection; 10 were received from Dr. K. M. Wheeler, and were isolated in Connecticut within the past 4 years; 3 were isolated in Texas in 1942, and were received from Dr. MacDonald Fulton; two were isolated recently in Rhode Island by Dr. C. A. Stuart; the remaining 17 were isolated in a number of different laboratories along the Atlantic seaboard. Eleven strains of Sh. ceylonensis were received, and 26 strains of Sh. dispar. All 37 strains produced acid from dextrose, lactose, maltose, and mannitol; failed to ferment salicin, and were indol positive. Further fermentation reactions are noted in Table I. Antiserums were prepared for 2 strains of Sh. dispar and one of Sh. ceylonensis. Table I presents a summary of the results obtained when the 37 strains were tested for agglutination in the various antiserums. The titers stated are those for the type strains listed, but all organisms grouped together behaved similarly.