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PubMed1998

Erythromycin resistance of Streptococcus pyogenes in Madrid.

BACKGROUND: Erythromycin is considered to be an adequate alternative to penicillin for patients who are allergic to penicillin. Erythromycin-resistant Streptococcus pyogenes strains have been reported in some parts of the world. METHOD: The in vitro activity of erythromycin and other antimicrobial agents was determined in a total of 1310 clinical Streptococcus pyogenes isolates collected in the city of Madrid from January, 1993, through December, 1996. RESULTS: All strains showed susceptibility to penicillin, rifampin, vancomycin and chloramphenicol. Tetracycline resistance was 8.5%. In 36 of the strains (2.7%) MIC was 4 microg/ml for ofloxacin. Clindamycin resistance was observed in only 18 strains (1.4%); this resistance was constitutive in 15 and inducible in 3 strains. Resistance to erythromycin was observed in 14.3% of the strains, showing an increase during the study period (2.0% in 1993 vs. 22.4% in 1996; chi square for linear trend 68.8, P < 0,0001); >90% of them showed the novel resistance phenotype described by Seppälä et al. and 32 of 32 of these strains showed by PCR the 1.4-kb fragment of the mefA gene recently described as the novel macrolide efflux resistance determinant. The erythromycin-resistant strains were isolated more often in pediatric patients (144 of 872) than in adults (44 of 438) (chi square 9.9, P = 0.0016). CONCLUSION: The study emphasizes the need to screen for resistance to macrolides in S. pyogenes and indicates that resistance to erythromycin in S. pyogenes has increased significantly in Madrid.

Adolescent↗
PubMed2002

Streptococcus pyogenes pyomyositis.

Group A beta-hemolytic Streptococcus pyomyositis continues to be an uncommon disease. We present a case of a 7-year-old boy with an M protein type 1, streptococcal pyrogenic exotoxin A and B, Streptococcus pyogenes pyomyositis and streptococcal toxic shock syndrome.

Antibodies↗
PubMed1998

Streptococcus sanguis bacteremia and colorectal cancer.

Streptococcal bacteremia is an uncommon presentation for colorectal malignancy, yet most physicians are aware of the association between Streptococcus bovis infection and these malignancies. Many are unaware, however, that other streptococcal species are associated with colon and rectal cancers. In this case report and brief review, we highlight this association and discuss a case of Streptococcus sanguis bacteremia associated with an early invasive rectal cancer.

Adenocarcinoma↗
PubMed2004

Thoracic spondylitis from a mycotic (Streptococcus pneumoniae) aortic aneurysm: a case report.

STUDY DESIGN: We report on a 54-year-old man with chronic lower back pain after recent streptococcus pneumoniae pulmonary infection, resulting in a mycotic aortic aneurysm and spondylodiscitis of the eighth vertebrae 6 months later. Successful surgical treatment and recurrence-free survival after 4 years are described. SUMMARY OF BACKGROUND DATA: Osteomyelitis by Streptococcus pneumoniae of the spine combined with contained rupture of a mycotic aortic aneurysm into lung and spine has not been reported to date. Mycotic aneurysms with pulmonary fistulas are reported to carry a mortality rate of up to 100%. Few cases have been reported with different operative and conservative strategies. METHODS: The mycotic aortic aneurysm was excised using extracorporeal circulation and replaced by a Dacron graft. The spondylitic section of the eighth thoracic vertebrae was radically resected, and a tricortical bone block from the iliac crest was inserted into the defect. To keep compartments separated, collagen sponges with antibiotic supplementation were used. A triple antibiotic therapy (Metronidazol 3 x 0.5 g/day, Cefotaxim 3 x 2 g/day, and Flucloxacillin 3 x 2 g/day) was prescribed for 6 weeks and changed to Clindamycin for 1 year thereafter. RESULTS: The patient made a good recovery and is free of recurrence 4 years after surgery. CONCLUSIONS: Lower back pain might be a projected pain. Particularly in older patients or in the presence of comorbidities resulting in an immunocompromised status, an aggressive workup may be indicated. Radical resection of inflammatory tissues, sparse use of implant material, and prolonged administration of antibiotics proved a successful strategy in this patient.

Aneurysm, Infected↗
PubMed2005

Subpectoral abscess a rare group A beta-hemolytic Streptococcus infection.

Suppurative complications of group A beta-hemolytic Streptococcus infection can present acutely and progress rapidly if prompt treatment is not initiated. Awareness of uncommon presentations is essential. We report a patient with a rare form of group A beta-hemolytic Streptococcus disease, subpectoral abscess.

Abscess↗
PubMed2003

Group B streptococcus: prevention of early-onset neonatal sepsis.

UNLABELLED: Group B streptococcus (GBS) was recognized as a major pathogen of neonatal disease in the 1970s. With a case-fatality rate of 5% to 20%, prevention of GBS neonatal disease has been an ongoing concern. The Centers for Disease Control and Prevention (CDC), and American College of Obstetricians and Gynecologists (ACOG) published guidelines for preventive strategies in 1996. These strategies, either a risk-based or a culture-based program, have been responsible for reduced incidence of GBS-newborn disease from 1.7 to 0.4 per 1,000 live births in the years 1993 to 1999. However, there has been considerable variability in practice patterns. Reanalysis now shows that a culture-based prevention strategy provides greater reduction in early-onset neonatal disease than a risk-based protocol. The CDC replacement guidelines of August 2002 recommend culture-based GBS prevention; the risk-based strategy is no longer supported. Continued efforts to eradicate GBS-newborn disease require an understanding of the pathogen, colonization, and transmission, GBS sampling and detection methods, and maternal therapy. Until a reliable vaccination against GBS is developed, prevention of neonatal GBS disease will rely upon intrapartum treatment of maternal carriers. TARGET AUDIENCE: Obstetricians & Gynecologists, Family Physicians LEARNING OBJECTIVES: After completion of this article, the reader will be able to define the pathogen, describe the methods of transmission and detection, and outline the current recommendations for maternal group B streptococcus therapy.

Colony Count, Microbial↗
PubMed1991

Intrageneric structure of Streptococcus based on comparative analysis of small-subunit rRNA sequences.

The partial 16S rRNA sequences of 24 Streptococcus species were determined by reverse transcription. A comparative analysis of these sequences and the sequences of seven previously studied streptococcal species revealed the presence of several clusters within the genus. The clusters obtained from the sequence analysis agreed in general with the groups outlined on the basis of the results of nucleic acid hybridization studies, but there were some exceptions. The pyogenic group was extended to include Streptococcus agalactiae, S. parauberis, S. porcinus, and S. uberis. Four oral groups were discerned; these four groups centered on S. mutans, S. salivarius, S. anginosus, and S. oralis. Some species (e.g., S. suis and S. acidominimus) did not cluster with any particular group. Our findings are discussed in the context of data from other genetic and chemotaxonomic studies.

Base Sequence↗
PubMed1995

"Streptococcus milleri" strains displaying a gliding type of motility.

Isolates belonging to the "Streptococcus milleri" species group that appear to exhibit a gliding type of motility, which is expressed as spreading growth on certain types of agar media, are described. These strains resembled a biotype of "S. milleri" that is usually isolated from genitourinary sources and is notable for its ability to ferment a wide array of carbohydrates. This biotype, which is currently included in the species Streptococcus anginosus, has been implicated in cases of neonatal infection. The "S. milleri" isolates which we studied lacked any observable organelles of motility and gave negative results when they were tested in conventional motility test medium stab cultures. Colonies growing on certain agar media, however, spread over the surfaces of plates and increased in area with increasing time of incubation. Chocolate agar supported maximum spreading, while this characteristic was barely discernible on blood agar. Electron microscopy studies revealed that there was more production of extracellular glycocalyx by motile strains than by a nonmotile isolate having a similar biotype. The results of an analysis of 16S rRNA gene sequences suggested that the motile strains are closely related to S. anginosus and represent a distinct rRNA population within the "S. milleri" species complex.

Base Sequence↗
PubMed1998

Phylogenetic diversity of Streptococcus suis strains of various serotypes as revealed by 16S rRNA gene sequence comparison.

The 16S rRNA gene sequences of reference strains of Streptococcus suis serotypes 1-34 and 1/2 were determined. A comparative sequence analysis showed that the degree of sequence similarity between S. suis reference strains ranged from 93.94 to 100%. A dendrogram was constructed from the similarity matrix. Thirty-two strains representing 32 serotypes fell into a major group divided into three clusters. The other strains, S. suis serotypes 32, 33 and 34, were more distant. Biochemical characterization of the six more distant strains, including S. suis serotypes 20, 22, 26, 32, 33 and 34, revealed a profile similar to that of other S. suis serotypes. Comparison of the 16S rRNA gene sequences of S. suis reference strains with sequences of other members of the genus Streptococcus indicated that, with the exception of S. suis serotypes 32, 33 and 34, reference strains did not cluster with any other species in the genus. In conclusion, 16S rRNA gene sequence analysis defined a major group of S. suis reference strains which were very closely related and a higher divergence for S. suis serotypes 32, 33 and 34. However, to date, there is no strong evidence to reclassify strains of these serotypes in another species.

Animals↗
PubMed1984

Inhibition of the synthesis and secretion of extracellular glucosyl- and fructosyltransferase in Streptococcus sanguis by sodium ions.

The influence of Na+ and K+ on the synthesis and secretion of extracellular glucosyltransferase (GTF; EC 2.4.1.5) and fructosyltransferase (FTF; EC 2.4.1.10) by Streptococcus sanguis NCTC 7865 and Streptococcus sanguis Challis NCTC 7868 has been determined. No FTF and little or no mutansucrase (GTF-I) activities were detectable during growth on glucose or sucrose unless the Na+/K+ ratio of the cultures was kept low. Increasing K+ concentrations stimulated the production of FTF and dextransucrase (GTF-S), but all glycosyltransferase activities decreased in high K+ media when the growth pH was maintained with NaOH instead of KOH, indicating that the Na+/K+ ratio effect was due principally to Na+ inhibition. Significant GTF and FTF activities were detected in a putative GTF- mutant of strain Challis grown in high K+ medium but not in high Na+ medium, suggesting that the mutant might be defective in a regulatory gene.

Culture Media↗
PubMed1990

Nucleotide sequence of the Streptococcus mutans gtfD gene encoding the glucosyltransferase-S enzyme.

The nucleotide sequence of the Streptococcus mutans GS-5 gtfD gene coding for the glucosyltransferase which synthesizes water-soluble glucan (GTF-S) has been determined. The complete gene contains 4293 base pairs and the unprocessed protein is composed of 1430 amino acids with a molecular mass of 159814 Da. The amino terminus of the unprocessed protein resembles the signal sequences of other extracellular proteins secreted by S. mutans and that of the GTF-I secreted by Streptococcus downei. In addition, the GTF-S protein exhibits high amino acid similarity with the strain GS-5 enzymes responsible for insoluble glucan synthesis (GTF-I, GTF-SI) previously isolated and sequenced in this laboratory. These results indicate that all three gtf genes evolved from a common ancestral gene.

Amino Acid Sequence↗
PubMed1990

Construction of NotI restriction map of the Streptococcus mutans genome.

Streptococcus mutans and Streptococcus sobrinus are the major causative organisms of human dental caries. Pulsed-field gel electrophoresis (PFG) showed that the restriction enzyme NotI produced ten and six DNA fragments from the genomes of S. mutans strain MT8148 and S. sobrinus strain 6715, respectively. The sizes of the chromosomes of S. mutans and S. sobrinus were each estimated to be about 2200 kb. The NotI restriction map of S. mutans MT8148 genome was constructed by Southern blot analysis with probes that overlapped two adjacent NotI fragments. Several virulence-associated genes of S. mutans were placed on the NotI restriction map. In addition, unique 'fingerprints' of S. mutans chromosomal DNA digested with NotI were produced by PFG, and these may be useful for epidemiological studies.

Base Sequence↗
PubMed1990

Characterization of the product of the gtfS gene of Streptococcus downei, a primer-independent enzyme synthesizing oligo-isomaltosaccharides.

The gtfS gene, coding for a glucosyltransferase which synthesizes water-soluble glucan and previously cloned from Streptococcus downei strain MFe28 (mutans serotype h) into a bacteriophage vector, was subcloned into a plasmid vector. The gtfS gene products expressed in Escherichia coli were compared to the primer-independent, oligo-isomaltosaccharide synthase in Streptococcus sobrinus strain AHT (mutans serotype g) and shown to resemble it closely in molecular mass, isoelectric point, immunological properties, optimum pH and Km values. The glucans produced from sucrose by the gtfS gene products are alpha-1,6-linked linear oligo-isomaltosaccharides without any branching sites. A similar gtfS gene was also detected on chromosomal DNA from S. sobrinus strain AHT.

Blotting, Western↗
PubMed1995

Characterization of Streptococcus suis capsular type 2 haemolysin.

The production of a haemolysin by Streptococcus suis capsular type 2 was investigated. Human group O erythrocytes were the most susceptible, followed by horse, sheep, cow and pig red blood cells, which exhibited similar susceptibilities; rabbit erythrocytes were the least susceptible. The haemolysin was produced at the end of the exponential growth phase. The toxin described in this paper was purified by affinity chromatography using a thiopropyl-Sepharose 6B column. It is an extracellular protein with a molecular mass of 65 kDa. The haemolysin belongs to the family of toxins known as antigenically related cholesterol-binding cytolytic toxins, since it shares common characteristics with other members of this family, such as sensitivity to oxygen and oxidizing agents, activation by reducing agents, inhibition by low concentrations of cholesterol, formation of transmembrane pores and a 'multihit' mechanism of action. In addition, anti-streptolysin antibodies inhibited the haemolytic activity caused by the S. suis haemolysin. Antibodies against the haemolysin could not be detected in pigs experimentally infected with a haemolytic positive strain of S. suis capsular type 2. To our knowledge, this is the only Lancefield group D Streptococcus producing a haemolysin with these characteristics. The role of this haemolysin in the pathogenesis of S. suis infections remains to be investigated.

Animals↗
PubMed2000

Localization and characterization of the ligand-binding domain of the fibrinogen-binding protein (FgBP) of Streptococcus equi subsp. equi.

The group C streptococcus Streptococcus equi subsp. equi possesses a 498-residue major cell-wall-associated protein (FgBP) which binds horse fibrinogen (Fg), reacts with convalescent horse serum and protects against lethal S. equi challenge in a small animal model. In the present study, analysis of a panel of 17 purified N- and C-terminal FgBP truncates by ligand affinity blotting and SDS-PAGE revealed that the region required for maximum binding of Fg extended over the first half of the mature protein. The C-terminal two-thirds of this domain is predicted to be alpha-helical coiled-coil and the N-terminal one-third to possess non-coiled-coil single strands. Residues at the extreme N-terminus and within the coiled-coil region are both required for ligand binding. A high incidence of alpha-helical coiled-coil structure also seems to be responsible in part for the aberrant mobility of FgBP on SDS gels. The efficiency with which FgBP binds Fg from different animal species decreases in the order horse > mouse, pig > rat > sheep, dog, bovine, human. Binding to horse Fg is inversely related to temperature over the range 45-4 degrees C and is independent of Ca2+ ions. MS analysis provided corroborative evidence that FgBP is covalently linked to the cell wall peptidoglycan.

Animals↗
PubMed2000

Investigation of the translation-initiation factor IF2 gene, infB, as a tool to study the population structure of Streptococcus agalactiae.

The sequence of infB, encoding the prokaryotic translation-initiation factor 2 (IF2), was determined in eight strains of Streptococcus agalactiae (group B streptococcus) and an alignment revealed limited intraspecies diversity within S. agalactiae. The amino acid sequence of IF2 from S. agalactiae and from related species were aligned and revealed an interspecies conserved central and C-terminal part, and an N-terminal part that is highly variable in length and amino acid sequence. The diversity and relationships in a collection of 58 genetically distinct strains of S. agalactiae were evaluated by comparing a partial sequence of infB. A total of six alleles were detected for the region of infB analysed. The alleles correlated with the separation of the same strains of S. agalactiae into major evolutionary lineages, as shown in previous work. The partial sequences of infB were furthermore used in phylogenetic analyses of species closely related to S. agalactiae, yielding an evolutionary tree which had a topology similar to a tree constructed using 16S rRNA sequences from the same species.

Alleles↗
PubMed2001

Environmentally regulated genes of Streptococcus suis: identification by the use of iron-restricted conditions in vitro and by experimental infection of piglets.

The identification of environmentally regulated genes of Streptococcus suis by the use of iron-restricted conditions in vitro and by experimental infection of piglets is described. Eighteen unique iron-restriction-induced (iri) genes and 22 unique in-vivo-selected (ivs) genes of Strep. suis were found. None of the ivs genes was exclusively expressed in vivo. Four iri genes were identical to four clones selected in piglets. Two ivs genes were similar to genes for putative virulence factors. One of these ivs genes was identical to the epf gene of virulent Strep. suis serotype 2 strains and the other showed homology to a gene encoding a fibronectin-binding protein of Streptococcus gordonii. Two additional ivs genes showed homology to environmentally regulated genes previously identified by using an in vivo expression technology (IVET) selection system in other bacterial species. One of these showed similarity to the agrA gene of Staphylococcus aureus, a key locus involved in the regulation of numerous virulence proteins. The promoter selection system described in this paper has been successfully used for the identification of many environmentally regulated genes potentially involved in the pathogenesis of Strep. suis infections in piglets.

Animals↗