Comparison of API Rapid Strep, Baxter MicroScan Rapid Pos ID Panel, BBL Minitek Differential Identification System, IDS RapID STR System, and Vitek GPI to conventional biochemical tests for identification of viridans streptococci.

Viridans group streptococci (36 stock strains and 167 single patient blood culture isolates) were assessed using API Rapid Strep, Baxter MicroScan Rapid Pos ID Panel, BBL Minitek Differential Identification System, IDS RapID STR System, and Vitek GPI methods. Identification data obtained with these systems were compared with those indicated by conventional biochemical procedures. API, Baxter MicroScan, BBL, IDS, and Vitek corresponded with conventional biochemical identification in 74%, 66%, 65%, 50%, and 61% of the isolates, respectively; using recommended supplemental tests, agreement was augmented in 9%, 11%, 20%, 11%, and 21% of the isolates, respectively. Disagreement with conventional biochemical methods occurred in 14%, 17%, 14%, 32%, and 10% of the commercial techniques, respectively; no identification was possible in 2%, 5%, fewer than 1%, 6%, and 8% of specimens, respectively. BBL, API, and Baxter MicroScan systems provided the most reliable rapid identification, although supplemental testing often was required. Until a higher percentage of correct identification data can be obtained without supplemental procedures, conventional biochemical techniques will remain the methods of choice for identification of viridans streptococci.

Complete structure of the cell surface polysaccharide of Streptococcus oralis C104: a 600-MHz NMR study.

Specific lectin-carbohydrate interactions between certain oral streptococci and actinomyces contribute to the microbial colonization of teeth. The receptor molecules of Streptococcus oralis, 34, ATCC 10557, and Streptococcus mitis J22 for the galactose and N-acetylgalactosamine reactive fimbrial lectins of Actinomyces viscosus and Actinomyces naeslundii are antigenically distinct polysaccharides, each formed by a different phosphodiester-linked oligosaccharide repeating unit. These streptococci all coaggregated strongly with both A. viscosus and A. naesludii strains, whereas S. oralis C104 interacted preferentially with certain strains of the latter species. Receptor polysaccharide was isolated from S. oralis C104 cells and was shown to contain galactose, N-acetylgalactosamine, ribitol, and phosphate with molar ratios of 4:1:1:1. The 1H NMR spectrum of the polysaccharide shows that it contains a repeating structure. The individual sugars in the repeating unit were identified by 1H coupling constants observed in E-COSY and DQF-COSY spectra. NMR methods included complete resonance assignments (1H and 13C) by various homonuclear and heteronuclear correlation experiments that utilize scalar couplings. Sequence and linkage assignments were obtained from the heteronuclear multiple-bond correlation (HMBC) spectrum. This analysis shows that the receptor polysaccharide of S. oralis C104 is a ribitol teichoic acid polymer composed of a linear hexasaccharide repeating unit containing two residues each of galactopyranose and galactofuranose and a residue each of GalNAc and ribitol joined end to end by phosphodiester linkages with the following structure. [----6)Galf(beta 1----3)Galp(beta 1----6)Galf(beta 1----6)GalpNAc(beta 1----3) Galp(alpha 1----1)ribitol(5----PO4-]n

Quantitative determination of the intracellular concentration of the various forms of HPr, a phosphocarrier protein of the phosphoenolpyruvate: sugar phosphotransferase system in growing cells of oral streptococci.

A simple procedure for quantitative estimation of the different phosphorylated forms of the phosphocarrier protein HPr in growing cells of oral streptococci is described. The growth of the cells was rapidly stopped by acidification of the medium and concomitant addition of the ionophore Gramicidin D. This procedure inactivated Enzyme I, HPr(Ser) kinase, HPr(Ser-P) phosphatase, and the enzymes involved in the metabolism of the allosteric effectors as well as the substrates of HPr phosphorylation. The cellular concentrations of HPr (His approximately P), HPr (Ser-P), HPr (His approximately P) (Ser-P), and free HPr were then determined by crossed immunoelectrophoresis.

Sequential 1H NMR assignments and secondary structure of an IgG-binding domain from protein G.

Protein G is a member of a class of cell surface bacterial proteins from Streptococcus that bind IgG with high affinity. A fragment of molecular mass 6988, which retains IgG-binding activity, has been generated by proteolytic digestion and analyzed by 1H NMR. Two-dimensional DQF-COSY, TOCSY, and NOESY spectra have been employed to assign the 1H NMR spectrum of the peptide. Elements of regular secondary structure have been identified by using nuclear Overhauser enhancement, coupling constant, and amide proton exchange data. The secondary structure consists of a central alpha-helix (Ala28-Val44), flanked by two portions of beta-sheet (Val5-Val26 and Asp45-Lys62). This is a fundamentally different arrangement of secondary structure from that of protein A, which is made up of three consecutive alpha-helices in free solution (Torigoe et al., 1990). We conclude that the molecular mechanisms underlying the association of protein A and protein G with IgG are different.

Comparison of albumin receptors expressed on bovine and human group G streptococci.

The albumin receptor expressed by bovine group G streptococci was extracted and affinity purified. The protein was characterized for species reactivity, and monospecific antibodies were prepared to the purified receptor. The bovine group G albumin receptor was compared functionally, antigenically, and for DNA homology with the albumin-binding protein expressed by human group G streptococci. In agreement with previous reports, the albumin-binding activity of human strains was mediated by a unique domain of the type III immunoglobulin G-Fc-binding molecule, protein G. The albumin receptor expressed by bovine group G strains was found to lack any immunoglobulin G-binding potential but displayed a wider profile of species albumin reactivity than protein G. Both albumin receptors could inhibit the binding of the other to immobilized human serum albumin, and each displayed similar binding properties. Antigenic comparison of the two albumin receptors demonstrated a low level of cross-reactivity; however comparison at the DNA level, using an oligonucleotide probe specific for the albumin-binding region of protein G, demonstrated that the two albumin receptors expressed by human and bovine group G streptococcal strains do not display significant homology.

A simple preparative procedure to extract and purify protein G from group G streptococci.

A rapid method for the solubilization of the bacterial type III Fc binding protein, protein G, from a group G streptococcus is described. Treatment of intact bacteria with cyanogen bromide results in the solubilization of a homogeneous Mr approximately 50,000 protein which retains IgG and human serum albumin binding properties. The solubilized protein could be purified to homogeneity by molecular sieving chromatography and retained all of the functional properties of the native protein.

A comparison of different methods of extraction of the M-protein from Streptococcus equi.

The molecular weights of the proteins produced in different extracts of Streptococcus equi were compared on immunoblots with antisera against acid extracted and mutanolysin extracted M-protein. Acid and alkaline extracts of S. equi contained some peptides of similar molecular weight that reacted with antiserum against an acid extracted 41,000 m.w. fragment suggesting that these fragments contained common epitopes. Comparison of the amino acid compositions of the 35,000 m.w. fragment of the alkaline extract and the 41,000 m.w. fragment of the acid extract suggest that these immunologically reactive fragments were probably derived from the same protein. Little cross-reactivity was observed between antisera against S. equi acid extracted protein and the native 58,000 m.w. M-protein. This suggests that conformational epitopes on the native M molecule are not present after acid treatment.

The structural analysis of a levan produced by Streptococcus salivarius SS2.

The structure of a water-soluble levan produced by Streptococcus salivarius SS2 has been determined by means of various chemical and instrumental methods. Methylation and periodate oxidation studies demonstrate that the levan is comprised of D-fructofuranosyl backbone residues linked beta-(2----6) (about 70%) with beta-(2----1) branches (about 30%). 13C-N.m.r. spectral analysis of the polymer is consistent with the structure determined by chemical means.

Purification and partial characterization of a cohaemolysin (CAMP-factor) produced by Streptococcus canis.

A cohaemolysin from the culture supernate of a canine pathogenic group G streptococcus (S. canis) was purified to electrophoretic homogeneity. The purification procedure involved ammonium sulphate precipitation, ultrafiltration, gel filtration and preparative isoelectric focusing. The cohaemolysin consisted of a single polypeptide chain, 18.6 kDa, with an isoelectric point at pH 5.1. The protein reacted with an homologous antiserum, appeared to be trypsin-sensitive and relatively heat-stable. The cohaemolysin did not show any non-specific IgG binding activities.

[Oral Streptococci - a scheme for the identification of Streptococcus mutans]. / Orale Streptokokken - Ein Beitrag zur Identifizierung von Streptococcus mutans.

A reliable simple scheme for the rapid identification of certain species of oral streptococci has been developed and compared with biochemical and physiological results of 45 well known clinical isolates and stock strains. Moreover, a method for the determination of H2O2 production was tested. With selected reactions as for instance acid formation in mannitol and raffinose broth, hydrolysis of arginine and esculin, the production of peroxidase, and the resistance of bacitracin the species S. rattus, S. sobrinus, S. mutans, S. cricetus, S. ferus, S. milleri, S. mitis, S. sanguis, S. mitior, and S. salivarius were differentiated.

Isolations of protein A and protein G from the bacterial surface.

Ten tested cultures each of Staphylococcus aureus (S. aureus) and of Streptococcus belonging to serological group G bound human IgG to a high extent. Protein A could be solubilized from strain Cowan I of S. aureus by lysozyme, mutanolysine, hydroxylammoniumchloride, hot acid extraction or lysostaphin and subsequently purified by affinity chromatography on human IgG-sepharose. The purified protein A preparation had molecular weights between 29,000 and 63,000 D and inhibited binding of 125I-labeled human IgG to S. aureus Cowan I. Protein G could be solubilized from strain 26540 of the G-streptococci with lysozyme or hot acid extraction and purified by affinity chromatography on human IgG-sepharose. The purified protein G revealed a molecular weight of 67,000 D and inhibited binding of human IgG to the G-streptococci.

[The detection of streptococcal cell-wall proteins that form complexes with human macroglobulins]. / Vyiavlenie belkov kletochnoi stenki streptokokkov, obrazuiushchikh kompleksy s makroglobulinami cheloveka.

The composition of the extracts of the cultures of individual streptococcal strains, studied by immunoblotting techniques, has been shown to contain proteins with a molecular weight of 70-80 KD. These proteins have pronounced affinity to human macroglobulins: alpha-macroglobulin, alpha-glycoprotein associated with pregnancy and protein A. The significance of this phenomenon on the cellular and somatic levels is discussed.

Expression and purification of a truncated recombinant streptococcal protein G.

The gene for Protein G from Streptococcus strain G148 was cloned and expressed in Escherichia coli. The regions on the gene corresponding to the albumin-binding domains and the Fab-binding region were then deleted by site-directed mutagenesis. The translation of regions corresponding to the cell-wall- and membrane-binding domains was prevented by introduction of stop codons upstream of these domains. This recombinant DNA sequence codes for a protein (G') that contains repetitive regions and that binds only the Fc portion of IgG, analogously to Protein A. Translation of the sequence produces a protein with an Mr of about 20,000. The nucleotide sequence differs from those published previously [Guss, Eliasson, Olsson, Uhlén, Frej, Jornvall, Flock & Lindberg (1986) EMBO J. 5, 1567-1575; Olsson, Eliasson, Guss, Nilsson, Hellman, Lindberg & Uhlén (1987) Eur. J. Biochem. 168, 319-324]. The protein can be substantially purified on a large scale by chromatography on IgG-Sepharose 4B. Homogeneous Protein G' can be prepared by anion-exchange f.p.l.c. on Mono Q HR. This Protein G' has a pI of 4.19 and SDS/PAGE gives an apparent anomalous Mr of 35,000.

Phenotypic characterization, cellular fatty acid composition, and DNA relatedness of aerococci and comparison to related genera.

Aerococci can be misidentified as streptococci, enterococci, pediococci, lactococci, or leuconostocs. To distinguish the genus and determine if another species is needed in the present taxon, we analyzed 37 aerococci for cellular fatty acids and compared them with 377 strains of gram-positive cocci, including the species type strains from each of the related genera. The cellular fatty acid profile of aerococci was distinguishable from other genera. Two relatively novel fatty acids found in the aerococci were identified as C16:1 omega 9c and C16:1 omega 9t. Eleven strains of aerococci (including a strain originally identified as "Gaffkya" species) were chosen for DNA-DNA reassociation studies with the type strain Aerococcus viridans ATCC 11563; DNAs from eight of these strains were more than 75% related to the type strain and had 1 to 4% divergence in related sequences. The remaining three strains were 60 to 70% related to the type strain, had 7 to 11.5% divergence, and may represent a second species, Aerococcus genospecies 2. beta-Glucuronidase, alpha-galactosidase, and beta-galactosidase were useful in characterizing the aerococci.

Faringitis clínica y estreptococos / Clinical pharyngitis and streptococcus

En este trabajo se hisoparon de 65 niños con diagnóstico clínico de faringitis. Un hisopo se empleó en la coaglutinación directa, Phadirect Strep A, y con el otro se inocularon dos placas: agar enriquecido con sangre humana y agar selectivo para estreptococos con sangre ovina. Ambas se inocularon a 36 oC, la primera en microareofilia y la segunda en anaerobiosis. Los estreptococos hemolíticos aislados se seroagruparon con Phadebact Streptococcus Test. La sensibilidad y especialidad del Phadirect frente al agar sangre humana fue de 93,7% y 95,9% y frente al agar selectivo, sangre ovina, fue de 89,5% y 100%, respectivamente. La incidencia de los distintos serogrupos fue para Estreptococos grupo A (EGA) 29,2%, Estreptococos grupo C (EGC) 26%, Estreptococos grupo G (EGG) 6% y Estreptococos grupo B (EGB) 1,5%. En el 63% de los niños se detectó algunos de estos serogrupos, mientras que la responsabilidad en el cuadro clínico (placas con menos de 30 colonias: portadores) correspondió a EGC (27,6%) y a EGC (13,8%).

Faringitis clínica y estreptococos / Clinical pharyngitis and streptococcus

En este trabajo se hisoparon de 65 niños con diagnóstico clínico de faringitis. Un hisopo se empleó en la coaglutinación directa, Phadirect Strep A, y con el otro se inocularon dos placas: agar enriquecido con sangre humana y agar selectivo para estreptococos con sangre ovina. Ambas se inocularon a 36 oC, la primera en microareofilia y la segunda en anaerobiosis. Los estreptococos hemolíticos aislados se seroagruparon con Phadebact Streptococcus Test. La sensibilidad y especialidad del Phadirect frente al agar sangre humana fue de 93,7% y 95,9% y frente al agar selectivo, sangre ovina, fue de 89,5% y 100%, respectivamente. La incidencia de los distintos serogrupos fue para Estreptococos grupo A (EGA) 29,2%, Estreptococos grupo C (EGC) 26%, Estreptococos grupo G (EGG) 6% y Estreptococos grupo B (EGB) 1,5%. En el 63% de los niños se detectó algunos de estos serogrupos, mientras que la responsabilidad en el cuadro clínico (placas con menos de 30 colonias: portadores) correspondió a EGC (27,6%) y a EGC (13,8%). (AU)

New receptor for human plasminogen on gram positive cocci.

180 bacterial strains representing 17 different species of gram positive cocci were tested for the ability to interact with human plasminogen. Receptors for plasminogen could be detected on 23/24 strains of S. pyogenes, 15/15 strains of S. equisimilis, 14/16 strains of human group G streptococci and 14/14 strains of S. pneumoniae. Eight of nineteen strains representing five species of alpha-hemolytic streptococci were also positive. S. equisimilis demonstrated the highest uptake with a median value of 58 per cent (20%-67%). On the other hand, all strains of S. agalactiae, the majority of S. faecalis and all S. aureus, S. epidermidis and S. saprophyticus strains tested were negative. The concentration of unlabelled plasminogen causing a 50 per cent reduction of bound tracer was between 50 and 150 mM. These estimates of the dissociation constant confirmed the specific nature of the interaction. Binding of plasminogen could be blocked by addition of plasmin-aprotinin complex, suggesting that plasminogen and plasmin bind to the same receptor. Binding was also blocked by the plasminogen fragment kringle 1-3, but not by miniplasminogen, a fragment containing kringle 5 and the B-chain region. As streptokinase interacts mainly with the B-chain of plasmin it is clear that the bacterial receptor for plasminogen is not identical to streptokinase.

DNA-DNA hybridization studies and phenotypic characteristics of strains within the 'Streptococcus milleri group'.

Twenty-five strains resembling 'Streptococcus milleri' were compared by DNA-DNA hybridization, by whole-cell-derived polypeptide patterns on SDS-PAGE, and by biochemical tests. Four homology groups were revealed by DNA-DNA hybridization. DNA homology groups 1, 2 and 3 were closely related and contained the type strains NCDO 2226 (Streptococcus constellatus), NCDO 2227 (Streptococcus intermedius) and NCTC 10713 (Streptococcus anginosus), respectively. DNA homology group 4 consisted of four strains received as variants of Streptococcus intermedius which were found not to be closely related to strains in groups 1-3. The data from SDS-PAGE polypeptide patterns and biochemical tests supported the recognition of three centres of variation within the 'Streptococcus milleri group' corresponding to DNA homology groups 1-3 and indicated that strains of DNA homology group 4 are members of an as yet undescribed species within the viridans streptococci.

Differences in virulence between two strains of Streptococcus suis type II after experimentally induced infection of newborn germ-free pigs.

Fifteen newborn germ-free pigs were inoculated with 2 strains, D-282 and T-15, of Streptococcus suis type II. Some pigs also were preinoculated with Bordetella bronchiseptica, which successfully predisposed them to S suis infection. The 2 streptococcal strains were differentiated by muramidase treatment, which released certain high molecular-weight proteins, termed muramidase-released proteins (MRP), from the cell wall of strain D-282, but not from the cell wall of strain T-15. Only strain D-282 (MRP-positive) induced clinical signs of disease and markedly increased neutrophil numbers in pigs. Streptococci were more frequently isolated from fecal swab specimens obtained from pigs inoculated with strain D-282 (MRP-positive) than from specimens obtained from pigs inoculated with strain T-15 (MRP-negative). Both strains were isolated from nasal swab specimens obtained from all infected pigs. Postmortem examination revealed fibrinopurulent meningitis, polyserositis, and polyarthritis in pigs inoculated with strain D-282; this strain was isolated from the CNS, serosae, visceral organs, heart, and joints. Whereas strains D-282 caused several pathologic changes, strain T-15, isolated from the lungs, caused only pneumonia. Both strains were isolated from the tonsils of all pigs. Virulence differed distinctly between the MRP-positive and the MRP-negative strains.