Hyaluronic capsule as one of the factors of hemolytic streptococcal pathogenicity]

Experiments were conducted on albino mice. It was shown that treatment of streptococci with testicular hyaluronidase or a single administration of the enzyme to infected animals failed to inhibit the infectious process. Injection of hyaluronidase solution to every 3 or 4 hours depressed the development of the process and increased the percentage of survived animals during its first stages. A marked intensification of the hyaluronidase action inhibiting the infectious process was observed under conditions of a moderately active or passive immunity and also in the case of preliminary treatment of streptococci with homologous immune serum. The data obtained permit to regard the hyaluronic capsule in the hemolytic streptococci as one of the pathogenicity factors of this microbial species providing survival of the causative agent after its entrance into the macroorganism.     

IgA-specific proteins of pathogenic bacteria

Data on structure and specificity of bacterial IgA receptors (IgA-binding M-like proteins Arp4 and Sir22 from hemolytic streptococci of serogroup A, β-antigen from hemolytic streptococci of serogroup B, and SSL family proteins from Staphylococcus aureus) are surveyed in this review. The principal conclusion derived from comparison is the fact that all bacterial receptors bind the same site in the IgA molecule overlapping with the binding site of endogenous human IgA receptor CD89. We assume that this site, consisting of spatially close amino acid strands Leu257-Gly259 in domain Cα2 and Pro440-Phe443 in domain Cα3, is subject to conformational rearrangement induced by the binding of antigen in the IgA active site.     

Abolition of Swarming of Proteus by p-Nitrophenyl Glycerin: Application to Blood Agar Media

Comparative plate counts were made of Staphylococcus aureus and Streptococcus pyogenes growing on blood agar supplemented with individual chemicals to abolish the swarming of Proteus. B-phenylethanol, sodium azide, and p-nitrophenyl glycerin (PNPG) were used as anti-swarm agents. Each anti-swarm agent effectively abolished swarming for 24 h, but azide failed to control swarming for longer periods of incubation. In addition, azide displayed growth inhibition towards the staphylococci and streptococci resulting in no hemolysis and reduced viable cell numbers with the streptococci. Phenylethanol showed reduced viable cell numbers with the streptococci and unreliable hemolytic reactions. At 0.1 to 0.3 mM, PNPG proved to be a superior anti-swarm agent in that it showed no growth inhibition and allowed normal hemolysis, but abolished swarming for extended periods of time. When laboratory strains of Streptococcus pneumoniae, Klebsiella pneumoniae, Pseudomonas aeruginosa. Listeria monocytogenes, and Vibrio cholerae were screened on a blood agar medium containing 0.1 mm PNPG, they displayed similar growth and hemolytic characteristics to the identical medium without PNPG.     

An inhibitor typing scheme applicable to Lancefield group E streptococci

A previously described inhibitor typing scheme for hemolytic streptococci has been utilized to test 12 well-characterized strains of group E streptococci. These strains were differentiated into five inhibitor production (P) types and four inhibitor sensitivity (S) types: seven different strain "fingerprints" (combinations of P-type and S-type) being demonstrated. Inhibitor production by group E streptococci was increased under conditions of anaerobic incubation. The inhibitor fingerprints were stable on repeated testing of strains and it is suggested that the scheme is of value both for the labelling of serologically untypable strains and for subdividing strains belonging to existing serotypes.     

New gene cluster for lantibiotic streptin possibly involved in streptolysin S formation

Streptolysin S (SLS) is a serum-extractable and oxygen-stable hemolysin produced by Group A Streptococcus. A SLS-deficient mutant in which transposon Tn 916 was inserted in a locus distinct from the sag gene cluster [Nizet et al. (2000) Infect. Immun. 68, 4245-4254] was obtained by filter mating of the transposon-harbouring Enterococcus faecalis strain and Streptococcus pyogenes BL(T). This mutant, N22, had completely lost the hemolytic activity, in consequence of insertion of a single Tn 916 into a hitherto-unknown lantibiotic gene cluster composed of 10 open reading frames. The arrangement and sequence of this lantibiotic gene cluster were similar to those of nisin and subtilin, and so we designated this new lantibiotic as streptin. The bactericidal activity of streptin was abolished on treatment with trypsin or proteinase K. The different host range and nucleotide sequence clearly distinguished streptin from streptococcins. Streptin was not hemolytic and its bacteriocin activity was independent of carrier oligonucleotides effective for SLS. The fact that N22 also lost the anti-bacterial activity against indicator streptococci reveals that the factor(s) required for lantibiotic formation plays an important role in SLS formation as well.     

Further Studies of Some “Nontypable” Group A Streptococci

Thirty-two strains of group A hemolytic streptococci which could not be M typed with the available typing sera in Nashville, Tenn., were reinvestigated at the Streptococcus Reference Laboratory in Colindale, England, in order to estimate the efficacy of other antisera not available in Nashville and newer techniques (the opacity factor inhibition test) of typing strains not isolated in England. Fifty percent were eventually typed and all but four contained enough M protein to suggest that they would have been typed had the appropriate typing sera been available. The results indicate that group A streptococci truly lacking M protein were seldom isolated from the Nashville children from whom the streptococci were cultured. Several factors responsible for nontypability were considered, including the nonavailability of the necessary type-specific antisera and loss of M protein due to a change from Matt to glossy colonial types in the laboratory.     

Sensitivity of the wound microflora of oncological patients to some new antibiotics]

Sensitivity of the microflora of the oncological patients' wounds to the new antibiotics, such as gentamicin, kanamycin, oxacillin, ampicillin and lincomycin was studied with the help of the disc method. The discs with the above antibiotics were prepared under laboratory conditions in accordance with the respective instructions in the WHO. Sensitivity of 429 bacterial cultures, including 98 cultures of pathogenic staphylocci, 45 cultures of Enterococci, 43 hemolytic streptococci, 143 cultures of Escherichia, 50 cultures of Ps. aeruginosa and 50 cultures of Proteus was determined. The studies showed that gentamicin was the most active antibiotic aganist all the microbial species isolated from the surgical and other wounds of oncological patients. It may be used in treatment of the infections caused by association of the microbes belonging to different species, as well as in treatment of purulent processes before elucidating their etiology, 16.7 per cent of the Enterococcal isolates were resistant to gentamicin. Monomycin, kanamycin, oxacillin, lincomycin and macrolide antibiotics at present are sufficiently active against pathogenic staphylococci and hemolytic streptococci.     

Streptococcal immunotherapy of a chemically induced murine fibrosarcoma: Effect of dose,route, sham surgery,and splenectomy on adjuvant action

Summary Adjuvant immunotherapy with hemolytic streptococci abates the growth of a syngeneic methylcholanthrene (MCA)-induced fibrosarcoma propagated in C3H/HeJ mice. Interperitoneal (IP) administration of streptococci either prior to or after tumor inoculation reduced neoplastic outgrowth. While subcutaneous (SC) administration of streptococci prior to tumor inoculation did not influence tumor outgrowth, SC treatment afterwards was effective. Thus, therapeutic effects of streptococcal vaccine depend upon the route and/or timing of administration.Surgery performed shortly before tumor inoculation abrogated host response to streptococci. On the other hand, surgery performed 3 days after tumor inoculation did not alter the adjuvant action of streptococcal vaccines. The failure of attempts to achieve an immunotherapeutic effect in splenectomized hosts suggests that the spleen was essential for the action of the streptococcal vaccine. Present address: Department of Surgery, The University of Texas Medical School at Houston, 6431 Fannin, Room 6240, Houston, Texas 77030, USA     

Bacterial fora of patients treated with bleomycin]

Microflora of the pharynx, nose, sputum and excrements was investigated. It was found that bleomycin therapy may induce or aggravate the shifts in microbiocenosis of the pharynx and sputum in the direction of pathogenization (increase in the number of Staph. aureus, hemolytic streptococci, enterobacteria). A tendency to elimination of bifidobacteria and appearance of Proteus in the excrements was observed. Complications associated with the treatment are rarely of infectious origin.     

Production of Double Zones of Hemolysis by Certain Strains of Hemolytic Streptococci of Groups A, B, C, and G on Heart Infusion Agar

This report describes the appearance of a double zone of hemolysis around surface colonies of certain strains of streptococci of groups A, B, C, and G incubated aerobically on sheep blood-Heart Infusion Agar. The occurrence of the altered hemolytic pattern was related to peroxide production by the organism. Anaerobic conditions and the incorporation of catalase into the agar abolished the double-zone pattern and caused reversion of the organisms to a beta-hemolytic pattern. The double-zone pattern can be confused with alpha hemolysis on surface growth.     

Novel Twin Streptolysin S-Like Peptides Encoded in the sag Operon Homologue of Beta-Hemolytic Streptococcus anginosus

Streptococcus anginosus is a member of the anginosus group streptococci, which form part of the normal human oral flora. In contrast to the pyogenic group streptococci, our knowledge of the virulence factors of the anginosus group streptococci, including S. anginosus, is not sufficient to allow a clear understanding of the basis of their pathogenicity. Generally, hemolysins are thought to be important virulence factors in streptococcal infections. In the present study, a sag operon homologue was shown to be responsible for beta-hemolysis in S. anginosus strains by random gene knockout. Interestingly, contrary to pyogenic group streptococci, beta-hemolytic S. anginosus was shown to have two tandem sagA homologues, encoding streptolysin S (SLS)-like peptides, in the sag operon homologue. Gene deletion and complementation experiments revealed that both genes were functional, and these SLS-like peptides were essential for beta-hemolysis in beta-hemolytic S. anginosus. Furthermore, the amino acid sequence of these SLS-like peptides differed from that of the typical SLS of S. pyogenes, especially in their propeptide domain, and an amino acid residue indicated to be important for the cytolytic activity of SLS in S. pyogenes was deleted in both S. anginosus homologues. These data suggest that SLS-like peptides encoded by two sagA homologues in beta-hemolytic S. anginosus may be potential virulence factors with a different structure essential for hemolytic activity and/or the maturation process compared to the typical SLS present in pyogenic group streptococci.     

Patterns in the epidemic process of scarlet fever in various territories differing in respect of climate and geography]

Observations carried out in Ashkhabad and Petrozavodsk permitted to reveal specific features of the epidemic process in scarlet fever at the territories differing in climato-geographic respect. This was expressed in a different level of morbidity, differences in the character of periodicity, seasonality and age structure of morbidity. Along with this there were noted differences in the spread of the carrier state of hemolytic streptococcus and of their biological properties, and also in the process of immunity formation in the population. The data obtained suggest that one of the causes of epidemiological differences in scarlet fever detected in the southern and the northern districts were peculiarities of the immunological reactivity of the population and a difference in the carrier state of the highly toxigenic streptococci.     

Expression of recombinant Streptolysin O and specific antibody production

Streptolysin O (SLO), an oxygen-labile cytolysin, is the cholesterol-binding exotoxin of hemolytic streptococci. Besides microbiological and pathological interests, this cytolysin has been used as a tool for permeabilization of biomembranes. SLO serves as a diagnostic reagent for determination of anti-SLO antibody titer in streptococcal infection. Availability of highly purified SLO, however, has been limited by low yield in streptococcal culture and purification process. Present subcloning of mature-type full-length SLO gene into an expression vector having strictly controllable araBAD promoter enabled efficient production of the cytolysin. Further, anti-SLO antibody with high specificity was obtained by immunizing with purified SLO protein.     

Septicaemic infections in pigs,caused by haemolytic streptococci of new Lancefield groups designated R,S and T

Pyogenic streptococci isolated from outbreaks and from sporadic infections in pigs and piglets were characterized by the almost unique combination of the properties of -haemolysis on horse blood agar and acid production from inulin. Three new serological groups were recognized, each with a single antigen different from those of any of the Lancefield groups. These antigens are polysaccharides located in the cell wall. About half the number of haemolytic streptococcal strains isolated from pigs were group R or group S streptococci, a few strains were group T streptococci, and the remaining strains were group L streptococci,S. equisimilis, group E streptococci, or group P streptococci, in this order of frequency. Only one out of about 150 haemolytic strains could not be identified serologically. Group R and group T streptococci differ from group S streptococci by acid production from raffinose. Infections with group R streptococci appeared to occur independently of age, whereas infections with group S streptococci were almost entirely confined to piglets.     

Interrelationships between the virulence and the presence of M-protein in hemolytic streptococcus group A]

Experiments on mice demonstrated that of hemolytic streptococci A M types 2, 3, 12, 22, 46, and 49 characteristic is the absence of parallelism between their virulence for mice and the presence of M+-colonies in the microbial population. There was also a greater virulence for mice of M-variants. The established changes in serological properties of the cultures passaged in vitro were brought to the acquisition of polyagglutinability by the passage cultures, and to the loss of type-specific protection by the immune sera against these cultures. A possibility of acquisition by passage cultures of a factor determining their high virulence for mice, nonidentical to M-protein, is discussed.     

Presumptive Identification of Group A, B, and D Streptococci

A battery of five tests was used for presumptive identification of the pathogenic streptococci. The non-serological methods included determination of hemolysis for all strains, bacitracin susceptibility for group A streptococci, hippurate hydrolysis by group B streptococci, and bile-esculin reaction for group D streptococci. Enterococcal group D streptococci were differentiated from non-enterococcal group D streptococci by 6.5% NaCl tolerance. Two other categories of streptococci resulted: beta-hemolytic streptococci non-groups A, B, or D; and alpha- or nonhemolytic streptococci, not enterococci, not further identified (viridans streptococci). The tests were used as a battery and not as single entities. In this manner more than 99% of the group A, 99% of the group B, 81% of the beta-hemolytic streptococci non-group A, B, or D, 99% of the group D enterococci, 97% of the group D non-enterococci, and 94% of the viridans streptococci were correctly identified.     

Glucitol is present in the group-specific polysaccharide of groupB Streptococcus

The group-specific polysaccharide of group BStreptococcus was found to contain 13% glucitol, a previously unrecognized component. The alditol was present in all types and strains of groupB tested but was not found in any other hemolytic streptococci. Glucitol was present in the same relative proportion in the groupB-specific polysaccharide prepared by three different methods. It could not be separated from the group-specific polysaccharide by immunoprecipitation with antisera to the groupB-specific polysaccharide or by ion-exhange chromatography on diethylaminoethyl cellulose.     

Identification of a novel insertion sequence element in Streptococcus agalactiae. bspeller@imib.rwth-aachen.de

Gain and loss of bacterial pathogenicity is often associated with mobile genetic elements. A novel insertion sequence (IS) element designated ISSa4 was identified in Streptococcus agalactiae (group B streptococci). The 963bp IS element is flanked by 25bp perfect inverted repeats and led to the duplication of a 9bp target sequence at the insertion site. ISSa4 contains one open reading frame coding for a putative transposase of 287 aa and exhibits closest similarities to insertion elements of the IS982 family which has previously not been identified in streptococci. Analysis of different S. agalactiae strains showed that the copy number of ISSa4 in S. agalactiae varies significantly between strains. The S. agalactiae strain with the highest copy number of ISSa4 was nonhemolytic and harbored one copy inserted in cylB, which encodes the membrane-spanning domain of the putative hemolysin transporter (Spellerberg et al., 1999. Identification of genetic determinants for the hemolytic activity of Streptococcus agalactiae by ISS1 transposition. J. Bacteriol. 181, 3212-3219). Determination of the distribution of ISSa4 in different S. agalactiae strains revealed that ISSa4 could be detected only in strains isolated after 1996, which might indicate a recent acquisition of this novel insertion element by S. agalactiae.     

Phenotypic characterization of tannin–protein complex degrading bacteria from faeces of goat

Tannin–protein complex degrading bacteria after enrichment were isolated from unadapted goat faecal samples. Based on the morphological, hemolytic and biochemical characters, the isolates were categorized in two groups comprising GF1–GF4 and GF5–GF6. All the isolates were gram-positive cocci, catalase negative belonging to different strains of Group D streptococci, Enterococcus faecalis. Among six isolates, GF1 was the most resistant that could tolerate up to 4% of tannic acid in the medium with no significant change in the morphology. Tannase activity was detected in all the isolates, indicating their tannin degrading potential while gallate decarboxylase activity was detected only in three isolates GF1, GF2 and GF6.     

In Vitro Bactericidal and Bacteriolytic Activity of Ceragenin CSA-13 against Planktonic Cultures and Biofilms of Streptococcus pneumoniae and Other Pathogenic Streptococci

Ceragenin CSA-13, a cationic steroid, is here reported to show a concentration-dependent bactericidal/bacteriolytic activity against pathogenic streptococci, including multidrug-resistant Streptococcus pneumoniae. The autolysis promoted by CSA-13 in pneumococcal cultures appears to be due to the triggering of the major S. pneumoniae autolysin LytA, an N-acetylmuramoyl-L-alanine amidase. CSA-13 also disintegrated pneumococcal biofilms in a very efficient manner, although at concentrations slightly higher than those required for bactericidal activity on planktonic bacteria. CSA-13 has little hemolytic activity which should allow testing its antibacterial efficacy in animal models.