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PubMed1975

Asymptomatic epidemic acquisition of group A Streptococcus: antibody response to extracellular and type-specific antigens.

The antibody response of 40 institutionalized children involved in an epidemic associated with asymptomatic pharyngeal acquisition of a group A, M-11, T-11 typeable Streptococcus was studied. Titers of antibody to streptolysin O and to deoxyribonuclease B determined in sera collected from patients within two weeks of positive throat cultures were significantly higher than those in sera of controls (P smaller than 0.001). However, there was no rise in antibody titers in sera obtained from these patients after an interval of three weeks. Type-specific antibody to the group A Streptococcus (type M-11) was assayed in the sera of 24 patients. No detectable antibody activity was found either in the initial sera or in sera collected eight months after the epidemic. Thus, the asymptomatic nature of this epidemic could not be attributed to the presence of detectable type-specific antibody in this population at the time of the epidemic. These observations suggest that asymptomatic pharyngeal acquisition of group A Streptococcus may occur in epidemic fashion in certain populations and may not be associated with evidence of an antibody response to the streptococcal organism.

Antibodies, Bacterial↗
PubMed1983

Estimation of the protective level of human IgG antibody to the type-specific polysaccharide of group B Streptococcus type Ia.

Human IgG antibody to the type-specific polysaccharide antigen of group B Streptococcus type Ia in the sera of mice was measured by enzyme-linked immunosorbent assay, previously standardized by quantitative precipitation, 24 hr after passive immunization with human serum or affinity-chromatographed antibody. The concentrations of antibody needed to protect mice against 90% lethal dose challenge varied with the bacterial inoculum and ranged from 0.25 to 1 microgram/ml using five strains of group B Streptococcus type Ia. Affinity-chromatographed antibody gave results comparable to serum, indicating the specificity of the antibody and the absence of other humoral factors in protection with this serum. Sera from 11 infected infants and their mothers had concentrations of antibody of less than or equal to 0.17 micrograms/ml, below the protective level delineated in the experimental model. Twelve percent of 50 adult women and 36% of 25 women colonized with group B Streptococcus type Ia had antibody levels of greater than or equal to 1 microgram/ml.

Adult↗
PubMed1993

Development of infection with Streptococcus bovis and Aspergillus sp. in irradiated mice after glycopeptide therapy.

The use of ofloxacin and glycopeptides was evaluated for the treatment of infections arising in C3H/HeN female mice irradiated with 8.3 Gy from a 60Co source. The 21 day regimen began 72 h after irradiation when each of five sets of experimental animals received three antimicrobial therapy regimens and a saline-treated control group. With 40 mice in each group, 20 were used to monitor survival, 20 for the recovery of bacteria from the liver culture. Treatment groups were oral ofloxacin 20 mg/kg/day; oral or intramuscular vancomycin 50 mg/kg/day; oral teicoplanin 50 mg/kg/day; ofloxacin and vancomycin; ofloxacin and teicoplanin; or saline. Bacteria recovered from saline treated mice were Enterobacteriaceae and Streptococcus spp. By comparison, fewer Enterobacteriaceae were isolated from ofloxacin treated mice and fewer Streptococcus spp. in both vancomycin and teicoplanin treated mice. However, glycopeptide-treated mice developed infection with Aspergillus fumigatus and glycopeptide resistant Streptococcus bovis. Mortality rates within 60 days of irradiation were 100% in all treatment and control groups with the exception of ofloxacin which was 25%-35%. These data suggest that glycopeptide therapy increases rates of systemic infection with fungi and antibiotic resistant bacteria in irradiated mice.

Animals↗
PubMed1995

Treatment with various antibiotics of experimental endocarditis caused by penicillin-resistant Streptococcus sanguis.

BACKGROUND: Streptococcus sanguis currently accounts for one-half of viridans streptococci. Treatment has become complicated due to the increase in resistance to penicillin and cephalosporins. The aim of the study was to assess the efficacy of various antibiotics as monotherapy and in association with gentamicin, in a experimental model of infective endocarditis in rabbits. The effects were compared with a control group and a group given classical penicillin-gentamicin treatment. MATERIAL AND METHODS: Infective endocarditis was induced in 180 rabbits with a clinical isolate of Streptococcus sanguis. Treatment was started 48 h after infection, and lasted 5 days. The animals were divided into nine groups of 20 rabbits: G1, untreated controls; G2, penicillin-gentamicin; G3, clindamycin-gentamicin; G4, imipenem; G5, imipenem-gentamicin; G6, teicoplanin; G7, teicoplanin-gentamicin; G8, vancomycin and G9, vancomycin-gentamicin. Response to therapy was evaluated by mortality curves, as negative blood cultures, concentration of S. sanguis in aortic vegetations and rate of sterilization of vegetations. RESULTS: Vegetation weight was significantly lower in treated groups than in controls; lower weights were found in G5, 6, and 9. G9 sterilized 75% of the vegetations. Death occurred in 25% of the control group and in 4.76% of G6 and 7. Blood cultures became negative most rapidly in G9. CONCLUSIONS: Combined treatment with vancomycin-gentamicin may be highly efficacious in patients with endocarditis caused by penicillin-resistant Streptococcus sanguis. Other combinations, such as imipenem-gentamicin and teicoplanin-gentamicin, may be also advantageous.

Animals↗
PubMed2006

Ventricular peritoneal shunt infection resulting from group B streptococcus.

OBJECTIVE: To report, to our knowledge, the first case of a ventricular peritoneal shunt infection by group B streptococcus occurring in infancy. DESIGN: Descriptive case report. SETTING: Neonatal intensive care unit in a tertiary referral military hospital. PATIENT: A 3-month-old, former preterm infant with a case of postoperative ventricular peritoneal shunt infection by group B streptococcus occurring in infancy. INTERVENTIONS: The infant's shunt infection was treated with a prolonged course of antibiotics, shunt removal, and eventual shunt replacement. He developed a persistently enlarging third ventricular region cyst, which ultimately required endoscopic surgical fenestration. MEASUREMENTS AND MAIN RESULTS: Currently, at 25 months of age, the patient has some moderate developmental delays but is otherwise healthy and making progress with no evidence of any recurrent infection CONCLUSIONS: Group B streptococcus should be considered as a potential pathogen in ventricular peritoneal shunt infections in infants even outside of the immediate neonatal period. Providers caring for infants should be especially cognizant of the potential risk for nosocomial infections in former premature neonates, especially following high-risk surgical procedures. Prompt recognition of ventricular peritoneal shunt infections and management to include early shunt removal and appropriate antibiotic coverage are recommended in an effort to optimize outcome.

Cross Infection↗
PubMed1999

A study of small-colony, beta-haemolytic, Lancefield group C streptococci within the anginosus group: description of Streptococcus constellatus subsp. pharyngis subsp. nov., associated with the human throat and pharyngitis.

beta-Haemolytic, Lancefield group C streptococci within the anginosus-species group were shown by genetic and phenotypic criteria to be heterogeneous and to constitute two distinct taxa related at subspecies level to Streptococcus constellatus and Streptococcus anginosus, respectively. The first group, referred to here as DNA group 1, comprised six strains with 86-100% intragroup overall genomic DNA relatedness; five of the strains were originally isolated from the human throat and one was from an abdominal mass. They shared 61-77% DNA relatedness (delta Tm values = 1.2-1.5 degrees C) with reference strains of S. constellatus and were clearly differentiated from S. constellatus (now named Streptococcus constellatus subsp. constellatus) by the ability to produce beta-N-acetylgalactosaminidase, beta-N-acetylglucosaminidase, beta-D-fucosidase, beta-D-galactosidase and beta-D-glucosidase. The name S. constellatus subsp. pharyngis is proposed for these strains on the grounds that they are genetically and phenotypically distinct and exhibit a predeliction for the human throat, being isolated also from cases of pharyngitis. The DNA G + C content is 35-37 mol%. The type strain is MM9889aT (= NCTC 13122T). The second group (DNA group 2) was formed by five beta-haemolytic, Lancefield group C strains originally isolated from various human infections. DNA group 2 strains (81-100% intragroup DNA relatedness) shared 60-72% DNA relatedness (delta Tm values = 2.1-4.1 degrees C) with S. anginosus strains NCTC 10713T and MAS 283 but were not clearly differentiated phenotypically from S. anginosus, showed no clear pattern of clinical association, and therefore are not formally proposed as a new subspecies here.

Bacterial Typing Techniques↗
PubMed2001

Streptococcus ovis sp. nov., isolated from sheep.

Seven strains of an unknown Gram-positive catalase-negative chain-forming coccus-shaped organism isolated from clinical specimens from sheep were characterized by phenotypic and molecular taxonomic methods. Comparative 16S rRNA gene sequencing studies demonstrated that the bacterium represents a new sub-line within the genus Streptococcus. The unknown bacterium was readily distinguished from recognized streptococcal species by biochemical tests and electrophoretic analysis of whole-cell proteins. Based on phylogenetic and phenotypic evidence, it is proposed that the unknown bacterium be classified as Streptococcus ovis sp. nov. The type strain of Streptococcus ovis is CCUG 39485T (= LMG 19174T).

Animals↗
PubMed2002

Isolation from a shea cake digester of a tannin-degrading Streptococcus gallolyticus strain that decarboxylates protocatechuic and hydroxycinnamic acids, and emendation of the species.

A facultatively anaerobic, mesophilic, non-motile, non-sporulating bacterium, designated strain B7, was isolated from an anaerobic digester fed with shea cake rich in tannins and aromatic compounds, after enrichment on tannic acid. The coccoid cells (less than 2 microm in diameter) occurred in pairs or short chains and stained gram-positive. Strain B7 fermented a wide range of carbohydrates (cellobiose, fructose, galactose, glucose, lactose, maltose, mannitol, melibiose, raffinose and trehalose), grew optimally at pH 7.0 and had a G+C content of 40.4+/-0.3 mol%. Strain B7 was closely related to Streptococcus gallolyticus ACM 3611T, a member of the Streptococcus bovis rRNA cluster, with a sequence similarity of 98% and a DNA hybridization value of 86 mol%. Isolate B7 hydrolysed tannic acid and decarboxylated gallic acid to pyrogallol, traits also observed in S. gallolyticus ACM 3611T. In addition, both strains decarboxylated protocatechuic acid to catechol, p-coumaric acid to 4-vinylphenol, caffeic acid to 4-vinylcatechol and ferulic acid to 4-vinylguaiacol. An unsubstituted para-hydroxyl group on the benzene ring was required for decarboxylation. Glucose addition markedly increased the conversion rate. As these traits were not described previously, emendation of the description of the species Streptococcus gallolyticus is proposed.

Anaerobiosis↗
PubMed1982

The acquisition of Streptococcus mutans by infant monkeys (Macaca fascicularis) and its relationship to the initiation of dental caries.

The acquisition and transmission of Streptococcus mutans by 16 consecutively born infant monkeys (Macaca fascicularis) was studied. The 16 infant monkeys were weaned in four groups and caged together to form a commune. Transmission from mother to infant occurred infrequently. Streptococcus mutans was isolated from nine of the mothers but only from the dental plaque of two infant monkeys at weaning at which time the predominant streptococci were S. sanguis and S. mitior. One further animal was colonized by S. mutants during the formation of the commune, but only after it was caged with an infant harbouring the same organism. For 46 d after the completion of the commune, the monkeys were fed a starch-based diet during which time S. mutans of serotypes c, e or h were isolated from the faeces of all 16 animals and from the dental plaque taken from the developmental groove of the first deciduous molar of 11 animals. Faecal transmission appeared to be an important factor in the spread of S. mutans between monkeys in the commune. The monkeys were then fed a caries-promoting high sucrose diet resulting in a rapid increase in the proportion of S. mutans in the plaque and in the faeces. Streptococcus mutans serotype e was more frequently isolated from both plaque and faeces and its predominance may in part be due to the production of a bacteriocin active in vitro against S. mutans serotype h and other species of oral streptococci isolated from monkey dental plaque. The proportion of S. mutans in the developmental groove 8 d after the introduction of the high sucrose diet was significantly related to both the caries status of the groove and the total caries score 6 months later. The results suggest that, in this model of human dental caries, S. mutans is the major bacterial factor in the initiation of tooth decay.

Aging↗
PubMed1998

Streptococcus pyogenes protein F promotes invasion of HeLa cells.

Although the Gram-positive bacterium Streptococcus pyogenes (group A streptococcus) has been considered an extracellular pathogen which adheres to human mucosal epithelium, the streptococcus possesses invasive capacity for cultured human epithelial cells. This study provides genetic and functional evidence supporting the conclusion that protein F is capable of mediating entry of S. pyogenes into HeLa cells. Using Tn916 insertion mutagenesis or an isogenic S. pyogenes strain with a defined mutation in the gene encoding protein F (prtF), it was observed that the invasive capacity was affected by the levels of surface-exposed protein F, but not by those of M protein. In addition, heterologous expression of protein F on Enterococcus faecalis conferred upon the bacteria an efficient invasive phenotype. Several assays demonstrated that both the fibronectin-binding domains of protein F, UR and RD2, were involved in host-cell invasion. In addition, coinfection experiments of HeLa cells with S. pyogenes and an Escherichia coli K-12 strain expressing an afimbrial adhesin AFA-I showed that the uptake of S. pyogenes did not permit internalization of the E. coli cells.

Adhesins, Bacterial↗
PubMed2002

cis-Acting elements that regulate the low-pH-inducible urease operon of Streptococcus salivarius.

Differential expression of the Streptococcus salivarius 57.I urease operon in response to pH is effected by repression of transcription from a proximal promoter, PUREI: To localize the cis-acting elements involved in the regulation of the urease operon, the intact promoter region and its derivatives were generated and fused to a promoterless chloramphenicol acetyltransferase (cat) gene. The promoter-cat fusions were established in the lacZ gene of S. salivarius by using a newly constructed integration vector. CAT-specific activities were examined in batch-grown cells at pH 7.5 and 5.5. The results indicated that a 21 bp region immediately 5' to the -35 element was required for efficient repression of PureI at neutral pH and that the 39 bp (-57 to -95) 5' to this region contained sequences required for optimal expression of PUREI: A potential secondary repressor-binding site was tentatively identified further upstream of the -35 element (-96 to -115). To further analyse the cis-acting elements, base changes were introduced into two AT-rich repeats within the primary repressor-binding site. One such derivative, S. salivarius M1, with five base substitutions immediately 5' to the -35 element, expressed 20-fold more CAT-specific activity at neutral pH than the strain carrying wild-type PureI-cat. Also, the pH sensitivity of strain M1 was greatly reduced, suggesting that this AT-rich region is crucial for repression of the urease operon. Deletion of three consecutive 15- or 16-base segments from -52 to -96 in the S. salivarius M1 background resulted in lower activities compared to strain M1, confirming the presence of sequences required for optimal expression of the operon. All of the PureI-cat fusions were also integrated into the gtfG gene of Streptococcus gordonii DL1, a non-ureolytic oral Streptococcus sp. Repression of PureI was observed at neutral pH in S. gordonii and the effects of the various mutations of the repressor-binding site largely paralleled those seen in S. salivarius, suggesting that the cis-elements may be a target for a global regulatory circuit that controls gene expression in streptococci in response to pH.

5' Flanking Region↗
PubMed2002

Expression of fibronectin-binding protein FbpA modulates adhesion in Streptococcus gordonii.

Fibronectin binding is considered to be an important virulence factor in streptococcal infections. Adhesion of the oral bacterium Streptococcus gordonii to immobilized forms of fibronectin is mediated, in part, by a high molecular mass wall-anchored protein designated CshA. In this study, a second fibronectin-binding protein of S. gordonii is described that has been designated as FbpA (62.7 kDa). This protein, which is encoded by a gene located immediately downstream of the cshA gene, shows 85 and 81% identity to the fibronectin-binding proteins PavA, of Streptococcus pneumoniae, and FBP54, of Streptococcus pyogenes, respectively. Purified recombinant FbpA bound to immobilized human fibronectin in a dose-dependant manner, and isogenic mutants in which the fbpA gene was inactivated were impaired in their binding to fibronectin. This effect was apparent only for cells in the exponential phase of growth, and was associated with reduced surface hydrophobicity and the surface expression of CshA. Cells in the stationary phase of growth were unaffected in their ability to bind to fibronectin. By utilizing gene promoter fusions with cat (encoding chloramphenicol O-acetyltransferase), it was demonstrated that cshA expression was down-regulated during the exponential phase of growth in the fbpA mutant. Expression of fbpA, but not cshA, was sensitive to atmospheric O2 levels, and was found to be up-regulated in the presence of elevated O2 levels. The results suggest that FbpA plays a regulatory role in the modulation of CshA expression and, thus, affects the adhesion of S. gordonii to fibronectin.

Bacterial Adhesion↗
PubMed1976

The elimination of urease activity in Streptococcus faecium as evidence for plasmid-coded urease.

A strain of Streptococcus faecium from the sheep rumen showed spontaneous loss of urease activity when subcultured at the normal rumen temperature of 38 degrees C, although in mixed cultures in vivo or in vitro loss of urease was not apparent. The rate of loss of urease in pure cultures was increased at incubation temperatures above 38 degrees C, but loss was never complete. However, at temperatures below 38 degrees C loss was greater, and at 22 or 18 degrees C the urease was completely eliminated. Incubation with sodium dodecyl sulphate (0-002%) or ethidium bromide (2-5 X 10(-5)M) caused complete loss of urease activity. The urease activity was also eliminated when the streptococcus was grown aerobically, and this loss of activity was irreversible. It is suggested that the urease activity is controlled by a plasmid gene and that aeration, low growth temperature and chemical agents 'cure' the streptococcus of the plasmid. Attempts to demonstrate the presence of covalently closed circular extrachromosomal DNA by caesium chloride-ethidium bromide equilibrium density-gradient centrifugation were unsuccessful.

Aerobiosis↗
PubMed2004

Streptococcus minor sp. nov., from faecal samples and tonsils of domestic animals.

Nine isolates, which were obtained from tonsils, anal swabs and faeces of dogs and from tonsils of a cat and a calf, constituted a homogeneous but unidentified taxon after screening with tRNA intergenic length polymorphism analysis and whole-cell protein fingerprinting. 16S rDNA sequence analysis classified representative strains in the genus Streptococcus. Highest sequence similarity (95.9 %) was obtained with Streptococcus ovis. Growth characteristics, biochemical features, DNA-DNA hybridization and DNA G+C contents of selected strains demonstrated that they represent a single, novel streptococcal species. The name Streptococcus minor sp. nov. is proposed for the novel species; the type strain (ON59(T)=LMG 21734(T)=CCUG 47487(T)) was isolated from a dog tonsil.

Animals↗
PubMed2005

Streptococcus castoreus sp. nov., isolated from a beaver (Castor fiber).

A previously undescribed, Gram-positive, catalase-negative, Streptococcus-like organism originating from a European beaver (Castor fiber) was subjected to a taxonomic study. The organism displayed beta-haemolytic activity and gave a positive reaction with Lancefield group A antisera. Based on the results of biochemical testing, the organism was tentatively identified as a member of the genus Streptococcus, but it did not correspond phenotypically to any recognized species of this genus. Comparative 16S rRNA gene sequencing studies confirmed this assignment, with the bacterium forming a hitherto unknown subline within the genus. Sequence divergence values of greater than 3 % from other reference streptococcal species, however, demonstrated that the unidentified coccus-shaped organism represents a hitherto unknown species. Based on phenotypic and molecular phylogenetic evidence, it is therefore proposed that the unknown organism from a beaver be classified as a novel species, Streptococcus castoreus sp. nov. The type strain is M605815/03/2(T) (=CCUG 48115(T)=CIP 108205(T)).

Animals↗
PubMed2004

Autolysin-targeted LightCycler assay including internal process control for detection of Streptococcus pneumoniae DNA in clinical samples.

The development and clinical evaluation of a LightCycler PCR assay, including an internal process control (IPC), to detect the Streptococcus pneumoniae autolysin gene in clinical samples is reported. The assay was developed to provide a second target for use in conjunction with existing pneumolysin PCR assays to increase the reliability of non-culture PCR diagnosis of pneumococcal infection. Primers amplify a 173 bp fragment of the autolysin gene (lytA), which is detected by fluorescence-labelled hybridization probes. An IPC was designed to check for the presence of PCR inhibitors and loss of assay sensitivity. The IPC product was amplified by the lytA primers and detected by a second set of hybridization probes. The analytical specificity of the autolysin PCR assay was 100% against 39 other bacterial species tested; these included related streptococci and other organisms. The assay, which could reliably detect 50 fg purified pneumococcal DNA per reaction, was capable of distinguishing between S. pneumoniae and atypical Streptococcus mitis and Streptococcus oralis strains known to contain the lytA gene. Using DNA extracts from a panel of EDTA bloods from patients with blood-culture-confirmed pneumococcal infection, the autolysin PCR had a sensitivity of 42.9%, which was similar to a previously reported TaqMan pneumolysin PCR (43.8%) run in parallel. Total agreement was shown between the autolysin assay and the pneumolysin TaqMan assay when used to test 23 culture-negative clinical samples, of which eight were positive by PCR, adding valuable clinical information. A specific autolysin-based LightCycler assay has been developed to complement pneumolysin PCR for the detection of S. pneumoniae in clinical samples. This should be a particularly useful tool for the rapid and sensitive diagnosis of pneumococcal meningitis, even after an antibiotic has been administered. However, poor sensitivity on blood samples limits its usefulness in other bacteraemic infections.

DNA, Bacterial↗
PubMed1995

Colonization of the oral cavity of mice by an unidentified streptococcus.

While studying the oral bacterial biota of mice, we observed an unidentified streptococcus (TG) that eventually became the dominant species of the oral cavities of all other mice in our animal facility. We found that the strain is indigenous to Jackson Laboratory mice but is absent in animals from Charles River Laboratories. TG was also transmitted from artificially contaminated BALB/c mice to the oral cavities of 4 other mouse strains. Streptococcus sp. TG stimulated the secretory and systemic immune systems of artificially contaminated Charles River BALB/c mice but did not provoke clinical symptoms. The increase in antibody level to TG did not prevent its colonization and persistence in these mice. In mice from Jackson Laboratory, the secretory and systemic immune response to TG was significantly lower. In vitro, Streptococcus sp. TG inhibited murine oral lactobacilli and staphylococci, probably due to the production of hydrogen peroxide.

Animals↗
PubMed2005

Mutacin production in Streptococcus mutans genotypes isolated from caries-affected and caries-free individuals.

Relationships between genetic diversity and mutacin production in Streptococcus mutans were evaluated in 319 clinical isolates from eight caries-affected and eight caries-free individuals. The isolates were submitted to mutacin typing and AP-PCR (arbitrarily primed polymerase chain reaction) assay. The mutacin production was detected for 12 Streptococcus sp. indicator strains. Results showed significant variations in the mutacin production profiles and the inhibitory spectra of both groups. A possible association was seen between mutacin activity and the distinct patterns of Streptococcus sp. colonization in the two groups. Genotyping by AP-PCR using the primers OPA-02 and OPA-13 revealed 101 distinct genotypes against 48 phenotypes identified by mutacin typing. No correlation was observed between the inhibitory spectra of mutacin and genotypic similarities based on AP-PCR analyses. According to our results, strains of the same S. mutans genotype showed different mutacin profiles, suggesting a high degree of interstrain diversity. In conclusion, mutacin production seems to be of clinical importance in the colonization of S. mutans and is highly diversified in the S. mutans species.

Adolescent↗