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PubMed2000

Postantibiotic effects and postantibiotic sub-MIC effects of amoxicillin on Streptococcus gordonii and Streptococcus sanguis.

Amoxicillin is one of the most frequently recommended antibiotics for prophylaxis of infective endocarditis in dental/oral procedures. In this study, the postantibiotic effect (PAE), postantibiotic sub-MIC (PASME) and sub-MIC effect (SME) of amoxicillin on oral streptococci, Streptococcus gordonii and Streptococcus sanguis, which are two of the major etiological agents in infective endocarditis, were investigated. The PAE was induced by 10 x MIC of amoxicillin for 2 h and the antibiotic was eliminated by washing. The PASMEs were studied by addition of 0.1, 0.2 and 0.3 x MICs during the postantibiotic phase of the bacteria, and the SMEs were studied by exposing bacteria to amoxicillin at the sub-MICs only. The PAE of amoxicillin was 2.0 h with S. gordonii DL1 and 0.7 h with S. sanguis MPC1. The PASME and SME of amoxicillin were observed both for S. gordonii DL1 and for S. sanguis MPC1. However, the durations of effects for S. sanguis MPC1 were shorter than those for S. gordonii DL1. The PASME values for both strains increased as the concentration of amoxicillin increased. The PASME values for both strains were substantially longer than the SME values. The present study illustrates the existence of PAE, PASME and SME for amoxicillin against S. gordonii and S. sanguis, thereby extending the pharmacodynamic advantages of amoxicillin for these bacteria in the prophylaxis procedures of infective endocarditis.

Amoxicillin↗
PubMed1980

Beta-haemolytic bacitracin sensitive strains of Streptococcus salivarius: a source of confusion with Streptococcus pyogenes in throat swab cultures.

Thirty strains of Streptococcus salivarius were beta-haemolytic when initially isolated from throat swabs and, because they were also bacitracin sensitive, they could be confused with the pathogenic Streptococcus pyogenes on primary culture plates. These strains were isolated form approximately 3000 throat swab cultures made in 6 mth, during which time 220 Lancefield group A organisms were also detected. Other features of these organisms, including loss of beta-haemolysis on subculture, penicillin resistance in half of the strains and ability to grow on MacConkey bile salt agar, are not shared by Strep. pyogenes, and their demonstration enables strains of the 2 species to be simply distinguished.

Bacitracin↗
PubMed2004

Group B Streptococcus (Streptococcus agalactiae) peritonitis associated with continuous ambulatory peritoneal dialysis (CAPD).

Streptococcus agalactiae typically induces serious infections in pregnant women and newborns. Nonpregnant adult patients can also be infected and mortality rate exceeds 40%. CAPD peritonitis is very rarely induced by S. agalactiae. Seven cases have been described previously and all had a very severe course, which included bacteremia, septic shock and death. A 27-year-old male with end-stage renal disease due to membranoprolipherative glomerulonephritis type I, who was on CAPD for 17 months, was admitted with the clinical and laboratory picture of CAPD peritonitis. Severe abdominal pain, shaking chills and fever 38.5 microC were also observed at presentation. Streptococcus agalactiae was isolated from the peritoneal fluid and blood culture was sterile. Under treatment with ceftazidime and tobramycin (i.p.) and vancomycin (i.v.) cultures became negative after 48 hours, abdominal symptoms resolved after 12 days and WBC count in the dialysate normalized after 14 days. As a possible source of infection the patient's partner was shown to be a vaginal carrier of a clone of S. agalactiae identical to that isolated in the peritoneal fluid. S. agalactiae is a rare cause of CAPD peritonitis with potentially very serious consequences. Anal or genital tract colonization is, in general, the source of contamination with S. agalactiae. The microbiological findings in the case presented here suggest that colonization of the patient or of his close environment may be important in the pathogenesis of S. agalactiae-induced CAPD peritonitis.

Adult↗
PubMed2005

[Severe Streptococcus agalactiae infection of the diabetic foot. A deleterious role of Streptococcus agalactiae?].

INTRODUCTION: Screening strategies among pregnant women have decreased the incidence of group B Streptococcus, which causes severe neonatal infections. The incidence of these infections has increased among diabetic patients, however. OBJECTIVES: To specify the characteristics of diabetic foot infections in which surgical samples have isolated one or several germs including group B Streptococcus, study its risk factors and determine its course. MATERIALS AND METHODS: We retrospectively evaluated the records of all patients admitted to the University Hospital of Geneva from January 1999 through October 2004, with diagnoses of severe foot infection (+/- osteomyelitis) documented during surgery. RESULTS: Twenty-five severe diabetic foot infections were identified, 21 with osteomyelitis. The most common risk factors were age older than 60 years (n=10), chronic renal failure (n=7), severe arteriopathy (n=6), and immune depression (n=2). Most lesions were classified as grade 3 or 4 of Wagner's classification. 80% of the surgical samples were polymicrobial. Blood cultures were positive in 4 patients, one in septic shock. Half the patients (n=13) underwent amputation, despite initially appropriate antibiotic treatment. No patients died but 3 relapsed. CONCLUSION: Group B streptococcal foot infections often occur in fragile patients with immune depression or severe arterial disease. Despite intensive antibiotic therapy and adequate debridement, amputation is often required in diabetic patients because of severe damage to the tissue and poor vascularization.

Adult↗
PubMed1989

Uptake of 14C-xylitol by xylitol-cultured Streptococcus sobrinus ATCC 27352 and Streptococcus mitis ATCC 36249 in vitro.

The effect of three successive cultures in the presence of 6% xylitol on the uptake of 14C-xylitol was studied using resting cells of Streptococcus sobrinus ATCC 27352 and Streptococcus mitis ATCC 36249. In the case of S. mitis, the three successive cultures did not alter the growth inhibition observed in the presence of xylitol. In the case of S. sobrinus, however, growth inhibition decreased. The 14C-xylitol uptake experiments also demonstrated that uptake of xylitol by S. sobrinus was decreased by culture in the presence of xylitol. Previous 14C-xylitol uptake levels were, however, re-established by culturing S. sobrinus in the presence of glucose alone. Culture in the presence of xylitol did not affect 14C-xylitol uptake in the case of S. mitis. These results show that S. sobrinus and S. mitis differ in the ways they handle of exogenous xylitol, and that uptake of xylitol by S. sobrinus could be reversibly regulated by addition xylitol to the growth medium.

Cell Division↗
PubMed1986

Susceptibility of enterococci. I. Inhibitory and bactericidal activity of several chemoantibiotics against Streptococcus faecalis and Streptococcus faecium.

The authors present a microbiological study of 100 strains of Enterococcus (70 strains of Streptococcus faecalis and 30 strains of Streptococcus faecium) tested for susceptibility to the following antibiotics, amoxicillin, ampicillin + flucloxacillin, piperacillin, rifampicin, vancomycin, netilmicin, ofloxacin, and norfloxacin. The assessment of minimum inhibitory and minimum bactericidal concentrations of these substances indicates that all have good inhibitory activity except netilmicin, which is active at higher concentrations; with rifampicin and vancomycin showing very poor bactericidal activity. The bactericidal activity of penicillins was hard to assess because of tolerance and paradoxical effect phenomena. The quinolones showed good inhibitory and bactericidal activity.

Anti-Bacterial Agents↗
PubMed1985

[Typing of Streptococcus faecalis and Streptococcus faecium strains with bacteriophages].

With a set of 17 bacteriophages specific for Streptococcus faecalis and a set of 7 bacteriophages specific for Streptococcus faecium 441 strains of S. faecalis and 53 strains of S. faecium were typed. The species identification was done by means of the API 20 STREP system. For S. faecalis 22 and for S. faecium 12 lysotypes were found. Among S. faecalis strains lysotype V6b was most common (27%), followed by the lysotypes XV (9,5%), XIII1 (7%), II1 (5,7%), and I1 (4,3%). These 5 lysotypes comprised 54% of all 441 strains. 21% of the strains of S. faecalis and 6 from 53 strains of S. faecium were untypable. Strains of S. faecium were most frequently isolated from faeces and in rare cases from urine. To the contrary 50% of the S. faecalis strains were isolated from urine. There was no correlation between special lysotypes and age of the patients or the source of specimen. The results of phage typing of several strains from one patient, and especially of strains from mothers and their newborns suggest the usefulness of the typing system to clarify epidemiological questions.

Adolescent↗
PubMed1966

The resistance to antibiotics of strains of Streptococcus viridans, Streptococcus faecalis, Escherichia coli, Pseudomonas aeruginosa, Proteus and Klebsiella isolated in Poland.

A nation-wide survey has been carried out in Poland into the susceptibility of six genera of bacteria to eight antibiotics. The antibiotic-resistance of streptococci differed from that of the Gram-negative rods studied.Escherichia coli, Klebsiella and Pseudomonas aeruginosa are known to be completely resistant to penicillin. Streptococcus faecalis was much more resistant to antibiotics than Streptococcus viridans (highest resistance to streptomycin - 90.3% and 74.9%, respectively; least resistance to chloramphenicol - 47.3% and 9.1%). More than 90% of all Pseudomonas aeruginosa strains isolated were resistant to all the antibiotics; high resistance was also exhibited by E. coli (94.5% resistant to erythromycin and 59.5% to chloramphenicol), Proteus (92.3% to penicillin and 63.0% to chloramphenicol) and Klebsiella (84.0% to erythromycin and 62.8% to oxytetracycline).

Anti-Bacterial Agents↗
PubMed1983

Trimethylsilyl-sugar profiles of Streptococcus milleri and Streptococcus mitis.

Seventy strains of 'viridans-group' streptococci were analysed gas chromatographically after preparation of trimethylsilyl ethers of their cellular sugars. The resulting profiles were evaluated as a possible aid to taxonomy. Glycerol, glucose, galactose, N-acetyl-glucosamine and N-acetylmuramic acid were found in all strains, in varying amounts. Rhamnose was the major neutral sugar in most strains, other than representatives of Streptococcus mitis, which invariably had ribose and usually anhydroribitol but no rhamnose. One strain of Strep. mitis possessed arabitol. Some strains of Strep. mitis and 'Strep. milleri' were alone in containing N-acetylgalactosamine. A combination of N-acetylgalactosamine and rhamnose in the absence of ribose was diagnostic for strains of 'Strep. milleri'.

Acetylgalactosamine↗
PubMed1976

Interaction of inflammatory cells and oral microorganisms. II. Modulation of rabbit polymorphonuclear leukocyte hydrolase release by polysaccharides in response to Streptococcus mutans and Streptococcus sanguis.

The release of lysosomal hydrolases from polymorphonuclear leukocytes (PMNs) has been postulated in the pathogenesis of tissue injury in periodontal disease. In the present study, lysosomal enzyme release was monitored from rabbit peritoneal exudate PMNs exposed to Streptocccus mutans or Streptococcus sanguis. S. mutans grown in brain heart infusion (BHI) broth failed to promote significant PMN enzyme release. S. sanguis grown in BHI broth, although more effective than S. mutants, was a weak stimulus for promotion of PMN hydrolase release. Preincubation of washed, viable S. mutans in sucrose or in different-molecular-weight dextrans resulted in the ability of the organisms to provoke PMN release reactions. This effect could bot be demonstrated with boiled or trypsinized S. mutans or with viable S. sanguis. However, when grown in BHI broth supplemented with sucrose, but not with glucose, both S. mutans and S. sanguis triggered discharge of PMN enzymes. The mechanism(s) whereby dextran or sucrose modulates PMN-bacterial interaction may in some manner be related to promotion of microbial adhesiveness or aggregation by dextran and by bacterial synthesis of glucans from sucrose.

Animals↗
PubMed1977

Transfection of Streptococcus sanguis by phage deoxyribonucleic acid isolated from Streptococcus mutans.

Streptococcus sanguis ATCC 10556 cells were infected with free phage DNA of S, mutans strain PK 1. Two transformants were isolated which made colonies with large mucoid forms on mitis-salivarius agar. Both transformants had an increased ability to synthesize insoluble glucan and showed an adhesive nature on glass surfaces. These characteristics of the transformants bear a resemblance to S. mutans. These transformants had many physiological characteristics by which they could be recognized as S. sanguis. However, they resembled S. salivarius in forming a large amount of soluble fructan. Furthermore, the transformant cells did not produce ammonia from arginine, whereas their parent cells did.

Bacteriolysis↗
PubMed1977

Molecular basis for the different sucrose-dependent adherence properties of Streptococcus mutans and Streptococcus sanguis.

The enzymatic and adherence properties of Streptococcus mutans GS5 and S. sanguis ST3, both isolated from human carious lesions, have been compared. During growth in sucrose media, S. mutans GS5 adheres to smooth surfaces approximately three times more effectively than dose S. sanguis ST3. However, strain ST3 does not display sucrose-dependent adherence under nongrowth conditions, whereas strain GS5 displays significant adherence. Although both organisms synthesize both water-soluble and -insoluble glucans, the glucosyltransferases from S. mutans GS5 synthesize much more adherent glucan molecules than do the comparable enzymes from S. sanguis ST3. Both cell types bind exogenous glucosyltransferases synthesized by strain ST3 equally well, whereas cells of strain GS5 bind the comparable enzyme fraction that it synthesizes to a greater degree than do cell of S. sanguis ST3. However, in contrast to the results with cells of S. mutans GS5, the absorption of the glucosyltransferase activity synthesized by S. mutans GS5 to the surface of S. sanguis ST3 results in low levels of subsequent sucrose-dependent adherence. These results are discussed in terms of the molecular basis for the sucrose-dependent adherence of the oral streptococci to smooth surfaces.

Adhesiveness↗
PubMed1994

[Parenchymatous abscess in Streptococcus anginosus (Streptococcus milleri) septicemia. Value of their systematic search, apropos of 4 cases].

Streptococcus anginosus, the term suggested to cover a set of streptococci previously known under various names (milleri, MG, anginosus, intermedius, constellatus), is characterized by a propensity to create parenchymatous abscesses, essentially cerebral or hepatic, particularly within the terms of septicemia. These abscesses are sometimes difficult to detect due to a difficult or non-existent symptomatology. The authors report on four cases illustrating the necessity to search for them systematically by cerebral CT scan and abdominal echography or CT scan in all cases of septicemia caused by Streptococcus anginosus.

Aged↗
PubMed2005

Use of partial budgeting to determine the economic benefits of antibiotic treatment of chronic subclinical mastitis caused by Streptococcus uberis or Streptococcus dysgalactiae.

The economic effect of lactational antibiotic treatment of chronic subclinical intramammary infections due to Streptococcus uberis or Streptococcus dysgalactiae was explored by means of partial budgeting. Effects at cow level and herd level were modelled, including prevention of clinical mastitis episodes and the prevention of transmission of infections. Input variables for our deterministic model were derived from literature or based on 2002/2003 dairy prices and farming conditions in The Netherlands. Sensitivity analysis was used to examine the effect of uncertainty around input variables or changes in price estimates. On farms where pathogen transmission was prevented through proper udder health management, 3-d antibiotic treatment during lactation resulted in an average net profit of euro+11.62 over no treatment while 8-d antibiotic treatment had an average negative net result of euro-21.83. Sensitivity analysis showed that profitability depends on the probability of treatment-induced cure, pathogen transmission rates, culling rate, retention pay-off, and costs of antibiotic treatment. Three-day antibiotic treatment of chronic subclinical streptococcal mastitis is economically profitable over a range of input values for cure probabilities, transmission rates and losses due to culling. In contrast, 8-d lactational treatment is only profitable for very valuable animals, on farms where the risk of pathogen transmission is high and/or when the farmer is likely to cull a high percentage of cows with subclinical mastitis. Because bacterial flora, cow characteristics and management differ widely between farms, the economic outcome of lactational treatment of chronic subclinical streptococcal mastitis may be highly farm-dependent.

Animals↗
PubMed1999

The effect of carbon dioxide on susceptibility testing of azithromycin, clarithromycin and roxithromycin against clinical isolates of Streptococcus pneumoniae and Streptococcus pyogenes by broth microdilution and the Etest: Artemis Project-first-phase study.

OBJECTIVE: To evaluate the effect of carbon dioxide on the susceptibility testing, using broth microdilution and the Etest (AB Biodisk, Solna, Sweden), of azithromycin, clarithromycin and roxithromycin against Streptococcus pneumoniae and Streptococcus pyogenes. METHODS: Fresh clinical isolates collected from 36 hospital laboratories in 12 countries were evaluated using the Etest in the presence of carbon dioxide. The isolates were retested under ambient conditions (absence of carbon dioxide) using broth microdilution and/or the Etest. RESULTS: Carbon dioxide falsely elevated azithromycin, clarithromycin and roxithromycin MIC90S for S. pneumoniae, determined by the Etest, approximately 12-fold. Also, the azithromycin MIC90 for S. pyogenes was increased fourfold; the effect was less marked for clarithromycin and roxithromycin. When isolates were retested in the absence of carbon dioxide, using the Etest or microdilution, susceptibilities to azithromycin were comparable to those to clarithromycin (S. pneumoniae, 93.4% versus 91.3%; S. pyogenes, 96.4% versus 95.8%). Both organisms were less susceptible to roxithromycin (S. pneumoniae, 71.3%; S. pyogenes, 85.7%). An internal standard control, consisting of 50 isolates each of S. pneumoniae, S. pyogenes and Haemophilus influenzae, confirmed that azithromycin susceptibility testing resulted in falsely elevated MICs. CONCLUSIONS: Carbon dioxide falsely elevated azithromycin MICs for S. pneumoniae and S. pyogenes, with an apparent reduction in susceptibility. When the in vitro activity of azithromycin and other macrolides against S. pneumoniae and S. pyogenes is being evaluated, awareness of the pH effect is essential.

Journal Article↗
PubMed1980

Prophage-Cured Derivatives of Streptococcus lactis and Streptococcus cremoris.

Prophage curing was achieved in Streptococcus lactis and Streptococcus cremoris, and the cured derivatives were shown to be indicators for their temperate bacteriophages. Relysogenization of these cured derivatives completed the first formal demonstration of the lysogenic state in lactic streptococci.

Journal Article↗
PubMed1981

Carbohydrate Fermentation by Streptococcus cremoris and Streptococcus lactis Growing in Agar Gels.

When lactic streptococci were embedded in agar gels and incubated at 30 degrees C, the end products of carbohydrate fermentation depended on the initial cell density, which determined the subsequent distribution and size of colonies in the gel. With high initial cell densities, microcolonies formed close together and lactose and glucose were converted almost entirely to lactate. However, inoculation with a small number of cells, which then grew to form widely spaced and comparatively large colonies, resulted in up to 30% diversion of end product, usually to formate, ethanol, and acetate. In these "low-colony-density" gel cultures, the initial rate of fermentation was exponential and only lactate was formed. However, this rate then became linear and fermentation became progressively more heterolactic. Streptococcus lactis ML(8) was the only strain among the 10 tested which remained homolactic. Incubation at temperatures either above or below the optimum for growth and metabolism decreased the diversion to end products other than lactate. The change from homo- to heterolactic fermentation appears to be caused by carbohydrate depletion in the vicinity of the colony, so that fermentation is then limited by the diffusion of substrate. Growth of cells on gel surfaces exposed to air resulted in up to 40% diversion of end product from lactate, mainly to CO(2), acetoin, 2,3-butanediol, and acetate. Six of the 12 Streptococcus cremoris strains tested remained homolactic under these aerobic conditions, whereas all 8 of the S. lactis strains tested, including ML(8), were heterolactic.

Journal Article↗
PubMed1981

Conjugal Transfer of Lactose-Fermenting Ability Among Streptococcus cremoris and Streptococcus lactis Strains.

Streptococcus cremoris C3 was found to transfer lactose-fermenting ability to LM2301, a Streptococcus lactis C2 lactose-negative streptomycin-resistant (Lac Str) derivative which is devoid of plasmid deoxyribonucleic acid (DNA); to LM3302, a Lac erythromycin-resistant (Ery) derivative of S. lactis ML3; and to BC102, an S. cremoris B(1) Lac Ery derivative which is devoid of plasmid DNA. S. cremoris strains R1, EB(7), and Z8 were able to transfer lactose-fermenting ability to LM3302 in solid-surface matings. Transduction and transformation were ruled out as mechanisms of genetic transfer. Chloroform treatment of donor cells prevented the appearance of recombinant clones, indicating that viable cell-to-cell contact was responsible for genetic transfer. Transfer of plasmid DNA was confirmed by agarose gel electrophoresis. Transconjugants recovered from EB(7) and Z8 matings with LM3302 exhibited plasmid sizes not observed in the donor strains. Transconjugants recovered from R1, EB(7), and Z8 matings with LM3302 were able to donate lactose-fermenting ability at a high frequency to LM2301. In S. cremoris R1, EB(7), and Z8 matings with LM2301, streptomycin resistance was transferred from LM2301 to the S. cremoris strains. The results confirm genetic transfer resembling conjugation between S. cremoris and S. lactis strains and present presumptive evidence for plasmid linkage of lactose metabolism in S. cremoris.

Journal Article↗