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PubMed2001

Streptococcus mutans lipoteichoic acid-induced apoptosis in cultured dental pulp cells from human deciduous teeth.

Herein, we suggest that Streptococcus mutans lipoteichoic acid-induced death of dental pulp cells on human deciduous teeth is caused by apoptosis. We provide evidence for the causal role of apoptosis in this process by demonstrating an increase in the proportion of fragmented DNA in such dental pulp cells, which results in a ladder pattern of DNA fragmentation. Additionally, Streptococcus mutans lipoteichoic acid-induced apoptotic cell death is suppressed by caspase inhibitor. Collectively, these findings suggest that Streptococcus mutans lipoteichoic acids may cause apoptosis in human dental pulp cells, and serve as an important factor in pulpitis.

Apoptosis↗
PubMed2000

Mechanism of hyaluronan binding and degradation: structure of Streptococcus pneumoniae hyaluronate lyase in complex with hyaluronic acid disaccharide at 1.7 A resolution.

Hyaluronic acid (HA) is an important constituent of the extracellular matrix; its bacterial degradation has been postulated to contribute to the spread of certain streptococci through tissue. Pneumococci and other streptococci produce hyaluronate lyase, an enzyme which depolymerizes HA, thus hyaluronate lyase might contribute directly to bacterial invasion. Although two different mechanisms for lyase action have been proposed, there was no crystallographic evidence to support those mechanisms. Here, we report the high-resolution crystal structure of Streptococcus pneumoniae hyaluronate lyase in the presence of HA disaccharide product, which ultimately provides the first crystallographic evidence for the binding of HA to hyaluronate lyase. This structural complex revealed a key interaction between the Streptococcus peneumoniae hyaluronate lyase protein and the product, and supports our previously proposed novel catalytic mechanism for HA degradation based on the native Streptococcus peneumoniae hyaluronate lyase structure. The information provided by this complex structure will likely be useful in the development of antimicrobial pharmaceutical agents.

Binding Sites↗
PubMed2002

Characterization and immunogenicity of pyrogenic mitogens SePE-H and SePE-I of Streptococcus equi.

Two pyrogenic mitogens, SePE-H and SePE-I, were characterized in Streptococcus equi, the cause of equine strangles. SePE-H and SePE-I have molecular masses of 27.5 and 29.5 kDa, respectively, and each is almost identical to its counterpart in Streptococcus pyogenes M1. Both genes are adjacent to a gene encoding a phage muramidase of 49.7 kDa and are located immediately downstream from a phage genomic sequence almost identical to a similar phage sequence in S. pyogenes M1. Strong mitogenic responses were elicited by both proteins from horse peripheral blood mononuclear cells. However, although both were pyrogenic for rabbits, only SePE-I was pyrogenic in ponies. Convalescent sera contained antibody to each mitogen and horses recovered from strangles or immunized with SePE-I were resistant to the pyrogenic effect of SePE-I. The immunogenicity of SePE-I suggests that it should be included in new generation strangles vaccines. In isolates of S. equi sepe-I and sepe-H were consistently present but they were absent from the closely related Streptococcus zooepidemicus, suggesting that phage mediated transfer was an important event in the formation of the clonal, more virulent, S. equi from its putative S. zooepidemicus ancestor.

Amino Acid Sequence↗
PubMed2000

A novel IS-like element frequently inserted in a putative virulence regulator in bovine mastitis isolates of Streptococcus dysgalactiae.

Streptococcus dysgalactiae, a Lancefield group C streptococcus, is commonly isolated from bovine mastitis. We recently identified a putative regulon in two S. dysgalactiae strains, 8215 and Epi9, consisting of two consecutive genes, dmg and dem, coding for a possible regulatory protein and an M-like protein with fibrinogen- and IgG-binding-properties, respectively. During these studies a short sequence homologous to an IS element was found to be inserted in the dmg gene of strain 8215. The present investigation describes the complete sequence of this IS-like element, named ISSdy1, which consists of 1218 bp and contains two ORFs, flanked by imperfect repeats. The nucleotide sequence of the IS-like element shows 82% identity to the previously reported sequence of IS199 from Streptococcus mutans V403. The deduced amino acid sequences of the ORFs also revealed high homology to transposases from IS elements in Enterococcus faecium, Escherichia coli, and Shigella dysenteriae, all belonging to the IS3 family. We studied the distribution of ISSdy1 in 57 S. dysgalactiae isolates using PCR analysis with specific primers derived from the IS element. Ninety-eight percent of the isolates contained the ISSdy1 element. Surprisingly, in the majority of studied strains a copy of the IS-like element was found to be inserted in the dmg gene, a putative virulence regulator.

Amino Acid Sequence↗
PubMed1998

Provisional quality control parameters and interpretive criteria for testing susceptibility of Streptococcus pneumoniae and Haemophilus influenzae to quinupristin/dalfopristin (RP59500). Antimicrobial Testing Quality Control Group.

Studies were undertaken to select tentative criteria for susceptibility testing of quinupristin/dalfopristin against Streptococcus pneumoniae and Haemophilus influenzae. Against 612 isolates of Streptococcus pneumoniae, MICs of quinupristin/dalfopristin were < or = 1.0 microg/ml for all but one strain. With a tentative MIC breakpoint of either < or = 1.0 microg/ml or < or = 2.0 microg/ml for susceptible, a disk diffusion zone diameter breakpoint of > or = 19 mm embraced all but two of the susceptible pneumococci; > or = 16 mm included all strains. For Haemophilus influenzae, MICs of quinupristin/dalfopristin clustered near the tentative breakpoints; 91.5% of the MICs were 2.0 to 8.0 microg/ml. This precluded satisfactory performance of the disk diffusion test in discriminating between resistant and susceptible isolates unless MIC breakpoints are modified for this species: clinical experience will be needed before that can be justified. Based on data from a multilaboratory study, the following quality control limits are proposed for Streptococcus pneumoniae ATCC 49619 when testing quinupristin/dalfopristin: 0.25 to 1.0 microg/ml for broth microdilution tests and 19 to 24 mm for disk diffusion tests. For tests of Haemophilus influenzae ATCC 29247, MIC limits are 2.0 to 16 microg/ml; disk tests were very reproducible but are not yet recommended.

Anti-Bacterial Agents↗
PubMed1990

In vitro activity of tosufloxacin (A-60969) and clarithromycin (A-56268, TE-031) against resistant Haemophilus influenzae, Streptococcus pneumoniae and Branhamella catarrhalis isolates.

The activity of tosufloxacin (A-60969), a new oral quinolone, and clarithromycin (A-56268, TE-031), a new oral macrolide, was compared in vitro to that of other oral quinolones and beta-lactam antimicrobial agents against clinical isolates of ampicillin and/or chloramphenicol resistant Haemophilus influenzae, penicillin resistant Streptococcus pneumoniae and beta-lactamase producing Branhamella catarrhalis. Results were compared to those for sensitive isolates. Tosufloxacin was the most active compound against Haemophilus influenzae and was more active than ciprofloxacin or ofloxacin against all strains of Streptococcus pneumoniae. Tosufloxacin was also more active than any of the beta-lactam drugs tested against penicillin resistant or relatively penicillin resistant isolates. Clarithromycin was the most active compound tested against both penicillin sensitive and penicillin resistant Streptococcus pneumoniae, and was as active as ciprofloxacin against Branhamella catarrhalis. In view of the favourable in vitro activity against common bacterial respiratory pathogens, tosufloxacin should be considered for clinical trials in adults with respiratory tract infections, while clarithromycin might be useful in treatment of infection with these organisms in all age groups.

4-Quinolones↗
PubMed2003

Antimicrobial resistance patterns of vancomycin-resistant Streptococcus equinus isolated from animal foods and epidemiological typing of resistant S. equinus by microbial uniprimer kit.

Raw milk samples, and cow and chicken intestines were tested to isolate vancomycin-resistant, gram-positive bacteria. From these samples, we isolated seven vancomycin-resistant Streptococcus equinus, two vancomycin-resistant viridans Streptococcus and two vancomycin-resistant Enterococcus faecium. The MICs of several antibiotics, including vancomycin, against these strains were tested. Seven isolates of S. equinus showed high level resistance to vancomycin and teicoplanin (>100 microg/mL). The cell wall thickness of these strains was compared with that of the sensitive strain by TEM and no differences were obserbed between these strains. We compared the strains of vancomycin-resistant Streptococcus equinus using PCR with Microbial Uniprimer Kit. We concluded that it is necessary to combine other methods in order to cluster and identify all isolates of S. equinus.

Animals↗
PubMed2000

Streptococcus suis meningitis, a poacher's risk.

Streptococcus suis infection is a zoonosis that has been mainly reported in pig-rearing and pork-consuming countries. The most common disease manifestation is meningitis, often associated with cochleovestibular signs. The causative agent is Streptococcus suis serotype 2, found as a commensal in the tonsils of its natural host, the pig. Persons at risk are mostly those with an occupational exposure to domestic pigs or their meat products. A case of meningitis caused by Streptococcus suis in a poacher who had killed and butchered a wild boar is reported. It appears that wild boar hunters are at additional risk of contracting the disease.

Animals↗
PubMed1999

[Streptococcus suis meningitis and neurophysiology of the acoustic system. First case report from Austria].

Meningitis caused by Streptococcus suis was diagnosed in a 63 year old female in Austria. Sixteen months after onset she still suffers from ataxia, disturbance of gait and bilateral hearing impairment. Being a farmer, the patient belongs to a recognized high-risk-group, as most other infected people do. To the best of our knowledge, there has been no report of a human infection by Streptococcus suis in Austria so far. The results of neurophysiological tests excluded a direct lesion to the cochlea during the acute phase of meningitis, and thus, are in contrast to the guinea-pig-model by Kay, who showed suppurative labyrinthitis being the cause of hearing loss. The present knowledge of Streptococcus suis meningitis with respect to neurophysiology, pathogenesis, epidemiology and increasing resistance against antibiotics is discussed.

Agricultural Workers' Diseases↗
PubMed2003

Purification of saliva agglutinin of Streptococcus intermedius and its association with bacterial aggregation and adherence.

Streptococcus intermedius strain 1208-1 cells were aggregated in the presence of saliva. The saliva agglutinin was purified by centrifugation, filtration, and gel filtration. SDS-PAGE analyses indicated that the purified agglutinin consisted of two high-molecular-mass proteins. Aggregation was dependent on calcium over pH 5.5, with 1 mM being the most effective concentration. Boiling inactivated purified agglutinin. S. intermedius strain 3 and Streptococcus mutans strain 1 were aggregated in the purified agglutinin. After adsorption with strain 1208-1 cells, the saliva sample did not exhibit any aggregation activity, and the agglutinin bands were no longer visible by SDS-PAGE. Adherence analyses demonstrated that the purified agglutinin immobilized on the surfaces of polystyrene wells, actinomyces cells, and apatite beads accounted for the binding of streptococcus cells. Agglutinin also effectively inhibited adherence to apatite beads coated with native saliva.

Actinomyces↗
PubMed1997

Cloning, sequence, and expression of the L-(+) lactate dehydrogenase of Streptococcus bovis.

The ldh gene encoding the fructose-1,6-diphosphate-dependent L-(+) lactate dehydrogenase from the ruminal bacterium Streptococcus bovis was cloned and sequenced. A genomic library of S. bovis JB1 DNA was constructed in lambda ZAP II and screened by use of a heterologous probe derived from the cloned Streptococcus mutans ldh gene. Several clones were isolated that contained a common 2.9-kb fragment as determined by restriction analysis. Nucleotide sequence analysis revealed a 987-bp open reading frame with extensive homology to Streptococcus thermophilus and S. mutans ldh nucleic acid and amino acid sequences. Expression of the cloned S. bovis ldh gene in Escherichia coli was confirmed by the ability to complement the ldh mutation of E. coli FMJ39, by using an in-gel activity screen and by enzymatic assay. Increased LDH activity was observed in S. bovis JB1 containing the cloned ldh genes on a multicopy plasmid.

Amino Acid Sequence↗
PubMed2003

Maternal postpartum group B beta-hemolytic streptococcus ventriculoperitoneal shunt infection.

BACKGROUND: Women with cerebrospinal fluid shunts require special management during the course of pregnancy. CASE REPORT: We describe a case of delayed postpartum ventriculoperitoneal shunt infection by Group B streptococcus in a 19-year-old who presented complaining of headache and a fever. The CSF culture from the shunt tap and the distal shunt tip both grew Group B beta-hemolytic streptococcus. CONCLUSION: Women who are colonized with Group B streptococcus and who have cerebrospinal fluid shunts should receive perinatal antibiotic prophylaxis, and may require more extended prophylactic antibiotics with cesarean section deliveries to prevent catheter tip colonization and subsequent shunt infection.

Adult↗
PubMed2002

Clonal relationships among isolates of erythromycin-resistant Streptococcus pyogenes of different geographical origin.

The clonal relationships among 261 erythromycin-resistant Streptococcus pyogenes isolates collected in 1986-1997 from nine countries in Europe and North and South America were studied by using two molecular typing methods: Vir typing and random amplified polymorphic DNA (RAPD) analysis. A total of 49 different Vir genotypes (VTs) and 33 different RAPD patterns were noted among the 261 isolates. Isolates that shared the same VT and RAPD pattern were considered to belong to the same clone. Although as many as 60 different clones were found among the isolates studied, only seven clones, comprising 157 of the 261 (60%) isolates, were found in more than one country. Five of these seven clones expressed the M phenotype known to be associated with the drug efflux mechanism, and only two clones expressed the macrolide-lincosamide-streptogramin B-resistance phenotype. The results indicate a polyclonal spread of erythromycin-resistant Streptococcus pyogenes. Furthermore, predominance of the seven clones indicates that erythromycin-resistant Streptococcus pyogenes of the same clonal origin may be widely distributed and found in several different countries.

Drug Resistance, Bacterial↗
PubMed2003

Multicentre study of the molecular epidemiology, serotypes and antimicrobial susceptibility patterns of invasive Streptococcus pneumoniae invasive isolated from children in the Ille de France area.

Between January 1997 and April 2002, 73 consecutive invasive strains of Streptococcus pneumoniae were isolated from children under 16 years of age in four hospitals in suburban Paris. Their genetic diversity was investigated by serotyping and analysis of pulsed-field gel electrophoresis restriction patterns. Antibiotic susceptibility patterns were analysed by disk susceptibility testing and determination of minimal inhibitory concentrations. The genetic basis of macrolide resistance was investigated by polymerase chain reaction. Studies of penicillin and vancomycin tolerance were performed for each strain. Despite the high prevalence (45.2%) of penicillin-nonsusceptible Streptococcus pneumoniae, resistance to amoxicillin (1.4%) was rare, and no strain was resistant to cefotaxime. Overall, 4.1% of pneumococcal strains were resistant to penicillin. Penicillin or vancomycin tolerance was not detected in any of the 73 strains studied. Of the erythromycin-resistant strains (48%), all but one carried the ermB gene. No strains showing a decreased susceptibility to ciprofloxacin (MIC, >4 mg/l) or overexpressing an efflux pump inhibited by reserpine were isolated. The serotypes found, in order of frequency, were as follows: 18C, 14, 6B, 19F, 19A, 9V, 23F, 1, 7F, 9A, 38. Strains of penicillin-nonsusceptible Streptococcus pneumoniae belonged predominantly to serotypes 14, 6B, 9V, 9A, 23F, 19F and 19A. The seven-valent conjugated vaccine covered 85.5% of the serogroups isolated in children under 2 years of age and 65.6% of the serogroups identified in children over 2 years of age. The genetic analysis showed a high identity for some serotypes, such as 14/9V, 6B and 23F. The use of the seven-valent conjugated vaccine is a critical measure to prevent invasive pneumococci infections in children in the Ille de France area.

Adolescent↗
PubMed2001

Penicillin-susceptible and erythromycin-resistant Streptococcus pneumoniae in children with acute mastoiditis.

Resistance to erythromycin is usually associated with resistance to penicillin in Streptococcus pneumoniae isolates. Over the last few years, however, an increase has been detected in the number of Streptococcus pneumoniae isolates obtained from children with acute otitis media complicated by acute mastoiditis. These isolates are characterized by a penicillin-susceptible and erythromycin-resistant antibiotic profile. This observation prompted a review of the microbiology database and analysis of all Streptococcus pneumoniae isolates with this peculiar antibiotic profile at a university hospital in Madrid, Spain.

Acute Disease↗
PubMed2003

Prevalence of cefotaxime resistance in group B streptococcus isolates from Osaka, Japan.

Streptococcus agalactiae (group B streptococcus; GBS) organisms are a major cause of severe infections, including bacteremia and meningitis in newborns. According to previous reports, GBS organisms are uniformly sensitive to penicillin G (PCG). The susceptibility of 117 strains isolated at Yodogawa Christian Hospital in Osaka, Japan, in 2001 was examined with the WalkAway system, using currently valid National Committee for Clinical Laboratory Standards (NCCLS) interpretive criteria. Twenty-one strains (18%) had intermediate susceptibility and 1 strain (1%) was resistant to PCG. Fifty-one strains (44%) had intermediate susceptibility to ampicillin (ABPC). No ABPC-resistant strain was found. Six GBS strains were selected from the 51 strains showing intermediate susceptibility to ABPC to determine the minimal inhibitory concentrations (MICs). The MICs of the 6 strains were: 1 microgram/ml to ABPC, 0.25 microgram/ml to PCG, 2 micrograms/ml to cefotaxime (CTX), 0.016 microgram/ml to panipenem (PAPM), and more than 4 micrograms/ml to erythromycin (EM). These 6 strains were distinctly resistant to CTX. Peak concentrations in excess of three to ten times the bactericidal concentrations at the site of infection are associated with the best clinical response. In meningitis caused by GBS whose susceptibility is intermediate or resistant to PCG or ABPC, it is difficult to maintain a sufficient therapeutic concentration in cerebrospinal fluid after the administration of these two agents. It is preferable to use PAPM, because the efficacy and safety of PAPM in the treatment of purulent meningitis caused by penicillin-resistant Streptococcus pneumoniae were established in Japan.

Adolescent↗
PubMed2006

Prevalence and persistence of certain serologic types of Streptococcus pyogenes in metropolitan Tokyo.

M-typing was conducted for Streptococcus pyogenes strains isolated within 1 week of admission from patients admitted to the Tokyo Metropolitan Toshima Hospital for scarlet fever in the 23-year period between 1956 and 1978. M12 was detected in the largest number of patients, followed by M6, M4, M3, and M1. T-typing was also conducted for Streptococcus pyogenes strains isolated from healthy schoolchildren in three different parts of the 20-year period between 1977 and 1998. T12 was detected in the largest number of children, followed by T28, T1, T4, and T6. These results suggested that strains of similar types are prevalent in scarlet fever patients and healthy carriers, that these strains become prevalent at intervals of several years, and that they are detected every year, albeit in a small number of persons, indicating that they are endemic. Isolated strains were typed by M-typing and T-typing. The results of typing were identical in more than 90% of cases. Comparison of major Streptococcus pyogenes strains isolated in Tokyo and three other major cities abroad showed that M12 was detected in the largest number of persons in Tokyo and New York and that major types were similar in the four cities.

Adolescent↗
PubMed2001

The emergence of erythromycin-resistant Streptococcus pyogenes in Seoul, Korea.

High frequencies of erythromycin-resistant streptococci were reported in Japan in the mid-1970s, and in Finland in the late 1980s, related to an increase in the consumption of macrolide antibiotics in these countries. The frequency of erythromycin-resistant Streptococcus pyogenes was reported to be only 2% in 1994, but we know that the susceptibility of the strains to antibiotics had not been tested routinely. We studied the resistance rates of Streptococcus pyogenes to various antibiotics in Seoul, Korea, where antibiotics could be purchased without prescription. From January through December, 1998, 92 isolates of group A streptococci were collected from inpatients and outpatients with pharyngotonsillitis or invasive streptococcal infections, from institutions in five different geographic areas of Seoul; one pediatric clinic, three university hospitals, and one general hospital. All isolates were serotyped by T-agglutination, and minimum inhibitory concentrations (MICs) were determined by agar dilution methods, according to the guidelines of the National Committee for Clinical Laboratory Standards (NCCLS). The most common T-serotype was T12 (44.6%), followed by T4 (19.6%). All the isolates tested were susceptible to penicillin, vancomycin, and cefotaxime. However, 38 isolates (41.3%) were resistant to erythromycin, 32 (34.8%) were resistant to clindamycin, and 48 (52.1%) were resistant to tetracycline. Twenty-seven of 41 isolates serotyped T12 and 3 of 18 isolates serotyped T28 were multiresistant to erythromycin, clindamycin, and tetracycline. Almost half of the isolates obtained from the five different areas in Seoul showed erythromycin resistance in Streptococcus pyogenes. Routine monitoring of antibiotic susceptibility tests and further extensive nationwide surveys are needed to determine the frequency and the extent of the spread of resistant strains in various geographic regions in Korea.

Adolescent↗