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PubMed1977

Subacute bacterial endocarditis due to Streptococcus mutans.

A case of subacute bacterial endocarditis due to Streptococcus mutans is presented. The case was successfully treated by intravenous and oral penicillin. Streptococcus mutans is a member of the viridans streptococcal group with properties similar to enterococcal streptococci. Since the enterococci are resistant to penicillin, and isolates of Streptococcus mutans are usually sensitive to penicillin, it is important that medical technologists and microbiologists accurately identify these organisms. The combination of the following characteristics: 1) lack of Group D antigen, 2) acid formation in mannitol broth, 3) failure to hydrolyze hippurate, and 4) formation in five per cent sucrose broth of gelatinous adherent deposits on walls and bottom of tube, distinguish Streptococcus mutans from enterococcal streptococci.

Adult↗
PubMed1995

Isolation and characterization of coaggregation-defective (Cog-) mutants of Streptococcus gordonii DL1 (Challis).

Streptococcus gordonii DL1 (Challis) bears coaggregation-mediating surface adhesins which recognize galactoside-containing surface polysaccharides on Streptococcus oralis 34, Streptococcus oralis C104, and Streptococcus SM PK509. Fifty-nine spontaneously-occurring coaggregation-defective (Cog-) mutants of S. gordonii DL1 unable to coaggregate with partner streptococci were isolated. Six representative Cog- mutants were characterized by their coaggregation properties with four Actinomyces naeslundii strains (T14V, PK947, PK606, PK984), Veillonella atypica PK1910, and Propionibacterium acnes PK93. The six representative Cog- mutants showed altered coaggregation with their streptococcal partners, A. naeslundii PK947, and P. acnes PK93. Based on the coaggregation phenotypes of these mutants, a model for the lactose-inhibitable coaggregation between S. gordonii DL1 and its partner bacteria is proposed. The potential use of these mutants in studies of oral biofilms is discussed.

Adhesins, Bacterial↗
PubMed1995

Neonatal infection with Streptococcus milleri.

Streptococcus milleri is a known commensal of the female genitourinary tract, but its pathogenicity in neonates has been reported in only a few cases. During a period of one year in an obstetrical unit, Streptococcus milleri was isolated from nine neonates and from one foetus after a spontaneous abortion. In seven of the nine newborns, neonatal infection was assessed and Streptococcus milleri was the lone pathogen involved, associated with positive blood or vaginal cultures in four mothers. Because Streptococcus milleri requires special conditions for identification, it is probably underestimated as a cause of neonatal infection and septic abortion.

Female↗
PubMed1983

Rapid identification of Streptococcus pyogenes by flow cytometry.

Flow cytometry combined with immunofluorescence of Streptococcus pyogenes was used to assay bacteria suspended in buffer solution and in saliva derived from throat swabs of healthy volunteers. The method allowed the enumeration of as few as 5 X 10(3) and 5 X 10(4) CFU per milliliter of buffer and saliva respectively. Controls including Streptococcus salivarius instead of Streptococcus pyogenes or buffer instead of specific antibodies confirmed the specificity of the detection of Streptococcus pyogenes in the samples. The results suggest that flow cytometry may serve as a basis for an automated reliable method for the diagnosis of streptococcal infections.

Culture Media↗
PubMed1995

Carriage of Streptococcus pyogenes among infants and toddlers attending day-care facilities in closed communities in southern Israel.

Infants and toddlers attending ten day-care facilities in closed communities in southern Israel were tested monthly for pharyngeal carriage of Streptococcus pyogenes and associated respiratory morbidity. Overall, the prevalence of Streptococcus pyogenes was 2.7% in infants and 8.4% in toddlers, reaching 8.5% and 17.8% in the two groups, respectively by midwinter. In 4 of 61 (6.6%) infants and 15 of 67 (22.4%) toddlers, the organism was recovered in more than one month (range 2 to 5 months). Streptococcus pyogenes in the pharynx was only associated with rhinitis during the spring and summer but not with other respiratory symptoms. During the study period, a mean of 0.9 strains were isolated in day-care facilities attended by infants, while a mean of 2.1 strains were found in toddlers. Young children attending day-care facilities show early acquisition of Streptococcus pyogenes in the pharynx.

Carrier State↗
PubMed2001

Determining the frequency of resistance of Streptococcus pneumoniae to ciprofloxacin, levofloxacin, trovafloxacin, grepafloxacin, and gemifloxacin.

Newer fluoroquinolones have good activity against Streptococcus pneunoniae and may be useful clinically for the treatment of pneumonia. Although resistance among Streptococcus pneumoniae has been reported, it is rare. The frequency of single-step resistance and the emergence of resistance were compared in serial transfer of 49 clinical isolates of penicillin-sensitive and -resistant Streptococcus pneumoniae to ciprofloxacin, levofloxacin, trovafloxacin, grepafloxacin, and gemifloxacin. Single-step resistance frequencies to four times the minimum inhibitory concentration were 2.73 x 10(-6) (+/- 8.46 x 10(-6)) for ciprofloxacin, 1.78 x 10(-7) (+/- 4.62 x 10(-7)) for trovafloxacin, 5.45 x 10(-7) (+/- 1.24 x 10(-6)) for grepafloxacin, 6.78 x 10(-7) (+/- 1.38 x 10(-6)) for gemifloxacin, and 9.23 x 10(-8) (+/- 4.47 x 10(-7)) for levofloxacin. In serial transfer experiments, all isolates became resistant to clinically relevant levels of all fluoroquinolones after eight passages. The resistance occurred most rapidly with ciprofloxacin followed by grepafloxacin, gemifloxacin, trovafloxacin, and levofloxacin. These results show that strains with decreased susceptibility to fluoroquinolones occur frequently in cultures of Streptococcus pneumoniae, and this organism can readily become resistant to clinically relevant concentrations of fluoroquinolones in vitro.

Anti-Infective Agents↗
PubMed2002

Prevalence, determinants, and molecular epidemiology of Streptococcus pneumoniae isolates colonizing the nasopharynx of healthy children in Rome.

The aim of this study was to determine the factors favouring Streptococcus pneumoniae nasopharyngeal colonization of healthy children attending daycare centres and to describe the circulation of penicillin-nonsusceptible strains using molecular techniques. A single nasopharyngeal swab was obtained from 610 children attending daycare centres in the southeast area of Rome. Streptococcus pneumoniae isolates were serotyped, and antibiotic susceptibility was assayed by the E test. The genetic determinants of erythromycin resistance were detected by a duplex polymerase chain reaction, and the penicillin-nonsusceptible isolates were typed by pulsed-field gel electrophoresis. The overall carriage rate of Streptococcus pneumoniae was 14.9%. Living with more than three persons in the same household was the only risk factor statistically associated with carriage. Sixteen of 85 (18.8%) strains were nonsusceptible to penicillin, and 44 (52%) were resistant to erythromycin. Of the erythromycin-resistant strains, the vast majority showed a high level of resistance and carried the erm(B) gene. The penicillin-nonsusceptible strains belonged to six different serotypes; molecular typing showed that in only one case (2 strains) was there a circulation of the same clone in the same daycare centre. In view of the high rate of resistant Streptococcus pneumoniae strains, risk factors for carriage of resistant strains were evaluated. Children who received macrolides in the previous month had a higher risk of being colonized by macrolide-resistant strains as well as by strains resistant to both penicillin and erythromycin. Limiting the use of antibiotics in children seems the most appropriate measure to control the spread of antibiotic-resistant strains.

Anti-Bacterial Agents↗
PubMed1999

Review of 17 cases of pneumonia caused by Streptococcus pyogenes.

Streptococcus pyogenes is an uncommon cause of community-acquired pneumonia and there have been few recent specific accounts of the condition. To describe the current nature of this disease in the UK, data was gathered on patients with clinical pneumonia from whom Streptococcus pyogenes was cultured principally from blood or other relevant normally sterile sites. In the Harrogate and Northallerton districts of North Yorkshire, pneumonia accounted for nine (20%) cases and a quarter of all deaths in a complete sequence of 45 patients with Streptococcus pyogenes bacteraemia detected during the 16-year-period 1981-1996. An analysis is presented of those cases together with eight recent cases from counties York, Durham and Isle of Wight during 1995-1997. Of the total 17 cases, nine occurred in women and eight in men; the age range was 30-92 years. The organism was isolated from blood culture in 15 (88%) patients. Eight (47%) patients died, five within 1 day of hospitalisation. Fourteen (82%) cases occurred in the winter months October to March, including all the fatal cases and all eight in which a clinical 'viral' prodrome was observed. Predisposing medical or surgical conditions were present in 65% of the patients. Major complications included septicaemia, pleural reaction, shock, pulmonary cavitation, osteomyelitis and metastatic abscesses. Seven serotypes of Streptococcus pyogenes were encountered, with M-type 1 predominating (the cause in 60% of cases). All infections were community acquired; two small clusters of fatal pneumonia were seen.

Adult↗
PubMed1995

Prenatal screening for group B Streptococcus. II. Impact of antepartum screening and prophylaxis on neonatal care.

OBJECTIVES: Our purpose was to evaluate the current practice of antimicrobial prophylaxis of preterm and low-birth-weight infants and to determine the impact of intrapartum fever, group B Streptococcus carriage, intrapartum antimicrobial therapy, and duration of membrane rupture on neonatal therapy. STUDY DESIGN: A total of 1356 members of the American Academy of Pediatrics were asked their practice regarding neonatal screening and antimicrobial prophylaxis. Respondents were asked to define how maternal fever, group B Streptococcus carriage, intrapartum antimicrobial therapy, and prolonged membrane rupture would affect their decisions regarding neonatal therapy. RESULTS: A total of 982 responses were obtained (72.4%). Routine antimicrobial prophylaxis is given to asymptomatic preterm neonates by 33.7% of pediatricians. Prophylaxis is inconsistently given at 32 to 36 weeks but is nearly universal after intrapartum fever, regardless of intrapartum therapy. If empiric intrapartum prophylaxis was given before a preterm birth, both the incidence (47.1% vs 29.1%) and frequency of prolonged neonatal therapy (30.1% vs 17.4% > or = 7 days) would be increased. Knowledge of maternal group B Streptococcus carriage would lead to a 2.6-fold increase in treatment (75.1% vs 29.1%) and 1.8-fold increase in the incidence of prolonged therapy of preterm infants (30.9% vs 17.4%), with 45.3% giving antibiotics for > or = 1 week if intrapartum treatment had been instituted. Surprisingly, 18% of pediatricians would treat term neonates without any risk factors other than maternal group B streptococcal carriage, and 32.7% would continue treatment for > or = 7 days. The majority of pediatricians (82.6%) felt that intrapartum prophylaxis would reduce early-onset group B streptococcal sepsis, but only 46.0% felt overall neonatal sepsis would be decreased by such therapy. CONCLUSIONS: Antepartum screening and intrapartum prophylaxis against group B Streptococcus by obstetricians may lead to an increased incidence and duration of treatment of preterm and term neonates by the pediatrician. The efficacy, cost, and risk of such treatment in broadly applied screening and treatment programs should be considered before a standard of care is established.

Antibiotic Prophylaxis↗
PubMed1985

Inhibition of [3H]-thymidine uptake in human gingival fibroblasts by extracts from human dental plaque, oral bacteria of the Streptococcus and Actinomyces species.

Extracts from human dental plaque, Streptococcus mutans, Streptococcus salivarius, Streptococcus faecalis, Streptococcus sanguis, Actinomyces israelli and Actinomyces odontolyticus inhibited [3H]-thymidine uptake by primary human gingival fibroblast cell lines as previous work has shown in respect of HeLa cells. The results show that a variety of oral bacteria, not usually considered to be periodontal pathogens, elaborate factors that adversely affect fibroblasts.

Actinomyces↗
PubMed1986

Effect of monoclonal antibodies against lipoteichoic acid from the oral bacterium Streptococcus mutans on its adhesion and plaque-accumulation in vitro.

Five monoclonal antibodies directed against Streptococcus mutans strain JBP lipoteichoic acid (LTA) were characterized. They were all similarly reactive with the immunizing LTA-containing extract, with intact Strep. mutans JBP cells and with LTA purified from Lactobacillus casei. Immobilized anti-LTA antibodies removes LTA from LTA-containing extracts. The binding of antibodies to LTA was inhibited by the aqueous extract but not by the organic extract of de-acylated LTA, indicating reactivity with the polyglycerol-phosphate portion of the molecule. Antibodies were reactive with all serotypes of Strep. mutans, as well as with strains of Streptococcus salivarius, Streptococcus sanguis and L. casei, but not with LTA-negative species Streptococcus mitis or Actinomyces viscosus. Anti-LTA antibodies at doses of 0.3 or 3.0 micrograms/ml, had no effect on the adherence of Strep. mutans JBP to experimental salivary pellicles formed on hydroxyapatite, but enhanced adherence 150-300 per cent at 30 micrograms/ml. There was no effect of anti-LTA antibodies in a chemostat model which measured sucrose-dependent plaque accumulation by Strep. mutans. The results argue against a major role for LTA in Strep. mutans adherence or plaque accumulation in vitro.

Adhesiveness↗
PubMed1995

Detection of binding of denatured salivary alpha-amylase to Streptococcus sanguis.

Native alpha-amylase, either solubilized, or immobilized and tested with an overlay immunotechnique, was bound in a species-specific manner to Streptococcus mitis and to one of the Streptococcus gordonii strains. However, only insignificant amounts of alpha-amylase were bound to Streptococcus sanguis and all other strains tested. When alpha-amylase was denatured before immobilization, Streptococcus sanguis bound strongly to the protein while binding of other strains was insignificant.

Bacterial Adhesion↗
PubMed1991

Group A streptococcus endocarditis: report of five cases and review of literature.

Group A streptococcus is an uncommon cause of infective endocarditis. We report five probable cases during a 10-year period (1980-1989) from a 750-bed community-teaching hospital. None of the patients were drug abusers. Group A streptococcus is the cause of infective endocarditis in between 0 and 5% cases in reported series. Since the introduction of penicillin 69 cases of group A streptococcus endocarditis have been reported in the literature. Clinical details of 14 patients, none of whom were drug abusers, are available. Included are our five cases. Eight patients had no underlying valve lesions. The overall mortality was 21% but only 15% for patients treated approximately. Among the 25 reported IV drugs abusers with group A streptococcus endocarditis and known valve involvement, right-sided heart valves were involved in 19 and left sided in six. The overall mortality was 9%.

Aged↗
PubMed1995

Superiority of conventional culture technique over rapid detection of group A Streptococcus by optical immunoassay.

An optical immunoassay (OIA) has been reported to be more sensitive than conventional culture for the detection of Group A Streptococcus, eliminating the need for culture. We attempted to confirm the sensitivity and specificity through a laboratory quantitation study and a clinical trial. OIA did not detect Group A Streptococcus below 10(5) colony forming units (CFU). Culture detected Streptococcus to 10(2) CFU from the inoculated swab. In the clinical study, throat swabs were obtained from 77 patients in an outpatient clinic. Compared with culture, the sensitivity of OIA was 78% and the specificity was 90%. These results demonstrate that OIA was less sensitive than culture in seeded experiments and missed 22% of positives in clinical practice. Our study, contrary to previous reports, suggests that OIA is not sensitive enough to be used as the sole assay for Group A Streptococcus pharyngitis.

Adult↗
PubMed2004

Endophthalmitis caused by Streptococcus pneumoniae.

PURPOSE: To investigate clinical settings, management strategies, antibiotic sensitivities, and visual acuity outcomes of endophthalmitis caused by Streptococcus pneumoniae. DESIGN: Retrospective, observational case series. METHODS: Records were reviewed of all patients with culture-positive endophthalmitis caused by Streptococcus pneumoniae treated at the Bascom Palmer Eye Institute between January 1, 1989 and December 31, 2003. MAIN OUTCOME MEASURES: Visual acuity and antibiotic sensitivities. RESULTS: Twenty-seven eyes of 27 patients met study inclusion criteria. The median follow-up was 7 months (range, 3 months to 10 years). Clinical settings included acute postoperative (10 eyes), corneal stitch abscess (5), corneal ulcer (3), bleb-associated (4), post-trauma (3), and endogenous (2). Eighteen cases (67%) were acute-onset (less than 3 weeks from event), with a median interval between event and presentation of endophthalmitis of 5 days (range, 1 day to 16 days). Nine cases (33%) were delayed-onset (median, 27 months; range, 3 to 121 months). Initial visual acuity was hand motions or better in 11 cases (41%). Initial therapeutic procedures included vitreous tap and injection of intravitreal antibiotics in 15 eyes (56%), pars plana vitrectomy and injection of intravitreal antibiotics in 10 eyes (37%), and evisceration in 2 eyes (7%). Seventeen (68%) of 25 eyes received intravitreal dexamethasone. Twelve patients (48%) received additional doses of intraocular antibiotics, and 11 patients (44%) underwent secondary surgical intervention within one week of diagnosis. The Streptococcus pneumoniae isolates showed sensitivity patterns as follows: 27/27 vancomycin, 13/13 clindamycin, 6/6 cefazolin, 11/11 ciprofloxacin, 14/14 moxifloxacin, 24/26 (92%) ofloxacin, 12/14 (86%) levofloxacin, 13/14 (93%) gatifloxacin, and 1/13 (8%) gentamicin. The organism was sensitive to at least one antibiotic administered initially in all cases. Final visual acuity was 20/400 or better in 8/27 (30%) cases, but 10 eyes (37%) had a final vision of no light perception. CONCLUSION: Despite prompt treatment with appropriate antibiotics, endophthalmitis caused by Streptococcus pneumoniae is associated with a poor visual prognosis.

Adolescent↗
PubMed2005

Comparison of early-onset neonatal sepsis caused by Escherichia coli and group B Streptococcus.

OBJECTIVE: The purpose of this study was to compare maternal characteristics and neonatal morbidity and mortality rates that are associated with early-onset neonatal sepsis that is caused by group B Streptococcus and Escherichia coli. STUDY DESIGN: This was a retrospective review of newborn infants with a positive blood culture (and/or cerebrospinal fluid) that was positive for either E coli or group B Streptococcus during the first week of life. Data were abstracted from maternal and neonatal medical records. RESULTS: Among 28,659 deliveries during the study period, 102 episodes of early-onset neonatal sepsis were identified, 61 of which were caused by group B Streptococcus and 41 of which were caused by E coli. E coli sepsis cases had a lower birth weight, a higher percentage with 5-minute Apgar score <7, and a longer stay in the hospital neonatal intensive care unit and required mechanical ventilation more frequently. Death after early-onset neonatal sepsis with E coli was also more frequent. CONCLUSION: Early-onset sepsis with E coli is associated with more morbidity and a higher mortality rate compared with early-onset group B Streptococcus.

Apgar Score↗
PubMed2005

Clinical, phenotypic, and genotypic evidence for Streptococcus sinensis as the common ancestor of anginosus and mitis groups of streptococci.

In 2002, we reported the discovery of a novel species of viridans streptococcus, Streptococcus sinensis. Recently, we reported the isolation of two more strains of S. sinensis. Clinically, S. sinensis is a definite cause of infective endocarditis, a characteristic mainly pertaining to the mitis group of streptococci. Phenotypically, two of the three S. sinensis isolates were Lancefield group F, a characteristic of the anginosus group. However, none of the three strains possess the caramel smell typical of this group of streptococci. Biochemically, S. sinensis was identified in 56% of the time as members of the anginosus group, and in 33% of the time as members of the mitis group. These clinical and phenotypic properties should be governed by the presence/absence or expressivity of particular genes in the S. sinensis genome. Genotypically, phylogenetic analysis using 16S rRNA gene sequences showed that S. sinensis branched out as the first branch in the anginosus group, implying that it is the ancestor of the other members of this group. However, the bootstrap value for S. sinensis clustered with members of the anginosus group is only 47%, meaning that it is often not clustered with members of this group, but the mitis group. Furthermore, the differences in the 16S rRNA gene sequences between S. sinensis and Streptococcus intermedius (3.7%) and those between S. sinensis and Streptococcus gordonii (3.6%) are almost the same. All these indicated that it is very likely that S. sinensis is the common ancestor of the anginosus and mitis groups of streptococci. Complete genome sequencing of S. sinensis and comparative genomics studies on the S. sinensis genome and genomes of members in the anginosus and mitis groups should reveal clues to the underlying genotypic differences that govern the different phenotypic properties of the two groups of streptococci, such as why streptococci of the anginosus group are prone to cause abscess formation but not infective endocarditis as compared to other viridans streptococci.

Genotype↗
PubMed2005

Anticariogenic activity of macelignan isolated from Myristica fragrans (nutmeg) against Streptococcus mutans.

The occurrence of dental caries is mainly associated with oral pathogens, especially cariogenic Streptococcus mutans. Preliminary antibacterial screening revealed that the extract of Myristica fragrans, widely cultivated for the spice and flavor of foods, possessed strong inhibitory activity against S. mutans. The anticariogenic compound was successfully isolated from the methanol extract of M. fragrans by repeated silica gel chromatography, and its structure was identified as macelignan by instrumental analysis using 1D-NMR, 2D-NMR and EI-MS. The minimum inhibitory concentration (MIC) of macelignan against S. mutans was 3.9 microg/ml, which was much lower than those of other natural anticariogenic agents such as 15.6 microg/ml of sanguinarine, 250 microg/ml of eucalyptol, 500 microg/ml of menthol and thymol, and 1000 microg/ml of methyl salicylate. Macelignan also possessed preferential activity against other oral microorganisms such as Streptococcus sobrinus, Streptococcus salivarius, Streptococcus sanguis, Lactobacillus acidophilus and Lactobacillus casei in the MIC range of 2-31.3 microg/ml. In particular, the bactericidal test showed that macelignan, at a concentration of 20 microg/ml, completely inactivated S. mutans in 1 min. The specific activity and fast-effectiveness of macelignan against oral bacteria strongly suggest that it could be employed as a natural antibacterial agent in functional foods or oral care products.

Anti-Bacterial Agents↗