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PubMed2003

A highly sensitive immuno-PCR assay for detecting Group A Streptococcus.

A highly sensitive hybrid assay, based on immuno polymerase chain reaction (immuno-PCR) and enzyme-linked immunosorbent assay (ELISA) techniques, was developed for the detection of pathogenic Group A Streptococcus (Strep A). Cells were disrupted by sonication and then coated onto the walls of Maxisorp microtiter plates. Next, biotinylated anti-Group A monoclonal antibody (mAb) was bound to the antigen and then linked, via a streptavidin (STV) bridge, to biotinylated reporter DNA. After extensive washing, the denatured reporter DNA was transferred to PCR tubes, amplified, electrophoresed, and used as the signal for detection of bacteria. The minimum detection limit of this assay is the equivalent of approximately one one-thousandth of a Streptococcus pyogenes cell, even in the presence of 100,000 Escherichia coli cells. The combination of multiple antigens per cell and PCR amplification provides the extreme sensitivity in this immuno-PCR assay. No cross-reaction was found with other Streptococcus species. We also directly linked the anti-Group A monoclonal antibody to DNA using succinimidyl 4-[N-maleimidomethyl]-cyclohexane-1-carboxylate (SMCC). The sensitivity using directly linked antibody-reporter DNA was approximately 10 cells. Because this assay could be adapted for detection of many different bacteria in a variety of sample types, we tested the potential for interference from substances that could be present in clinical, food, and environmental samples. Sonicated meat or human plasma did not inhibit detection; however, extracts of concentrated soil samples were somewhat inhibitory. This highly specific, sensitive, and robust assay could be applied to clinical detection of Group A Streptococcus and serves as a model for other immuno-PCR assays.

Antibodies, Monoclonal↗
PubMed2001

Preventing recurrent second trimester group B streptococcus chorioamnionitis by intermittent prophylactic ampicillin.

BACKGROUND: Whereas carrying group B streptococcus during pregnancy is common, second trimester group B streptococcus chorioamnionitis with intact membranes is rare, and recurrence of the latter problem even more so. CASE: A 38-year-old multipara with a history of recurrent second trimester group B streptococcus chorioamnionitis resulting in pregnancy loss was treated, beginning at 14 weeks' gestation, with monthly prophylactic ampicillin therapy throughout pregnancy and delivered a healthy male infant at term. CONCLUSION: In women with recurrent pregnancy loss due to second trimester group B streptococcus chorioamnionitis, an intermittent prophylactic antibiotic regimen throughout pregnancy might increase the probability of successful pregnancy.

Adult↗
PubMed1987

Lectin mediated adhesion of Streptococcus pneumoniae and its specific inhibition in vitro and in vivo.

According to our hypothesis, bacterial lectins play an important role in the organotropy of infectious diseases which is analogous to the metastasis of tumor cells. As a model for proving this, we investigated the specific lectin of Streptococcus pneumoniae, which has N-acetyl-D-glucosamine/D-galactose (GlcNAc-Gal) specificity. In vitro, after incubation with Streptococcus pneumoniae, cryotome sections of various organs from Balb/c-mice showed remarkable quantitative differences of bacterial adhesion to the organ cells. Whereas lungs and meninges were closely settled with bacteria, attachment to other organs (e.g. liver, spleen, brain) was lacking. In vitro lectin-blocking by GlcNAc completely prevented the adherence of Streptococcus pneumoniae to lungs and meninges. Other non-related carbohydrates (e.g. D-mannose, D-xylose) showed no effect. During in vivo experiments with Balb/c-mice, intratracheal application of Streptococcus pneumoniae led to a diffuse settlement of the lung. However, bacterial lectin-blocking with intratracheal GlcNAc administration completely inhibited adhesion to the organ cells of the lung. Therefore blocking of bacterial adhesins with competitive specific monosaccharides can completely prevent bacterial adhesion processes, a fact, which opens therapeutical aspects.

Animals↗
PubMed1999

Nonclostridial gas gangrene due to Streptococcus anginosus in a diabetic patient.

Streptococcus anginosus was recently identified as a distinct species from the other members of Streptococcus milleri group (Streptococcus constellatus, Streptococcus intermedius). We report a rare case of nonclostridial gas gangrene caused by S. anginosus. A 62-year-old diabetic woman was admitted with gas gangrene of the perineal area. She had been taking her oral hypoglycemia medication regularly for 10 years, but the diabetes was inadequately controlled. She was treated with surgical debridement of the necrotic tissue, insulin injection, and antibiotic therapy, and had a satisfactory clinical course.

Diabetes Mellitus, Type 2↗
PubMed2000

[Streptococcus pyogenes: in vitro susceptibility and role of beta-lactamase producing bacteria in the persistence of streptococcal pharyngotonsillitis].

OBJECTIVE: To assess the frequency of association between Streptococcus pyogenes and beta-lactamase-producing-bacteria in the pharyngotonsillitis and the evaluate the in vitro susceptibility. DESIGN: Prospective, descriptive, transverse study. SETTING: The present study was carried out in the Health Center Dr. José Castro Villagrana, in Tlalpan, México, D.F., from Juanary, 1996 to February 1999. PARTICIPANTS: In three hundred and ninety four patients with pharyngotonsillitis diagnosis we isolated the same number of Streptococcus pyogenes, and possible beta-lactamase-producing-bacteria. RESULTS: In 180 patients (45.7%) we isolated at least one possible beta-lactamase-producing-bacteria. Of these, in 138 patients (35%) were confirmed the enzyme presence. In total, we isolated 218 possible beta-lactamase-producing bacteria, and 152 (69.7%) were beta-lactamase positive. We found no significant change in the in vitro susceptibility of group A Streptococcus to penicillin, but erythromycin resistance is relatively common, approximately 10% in this study. CONCLUSIONS: Streptococcus pyogenes was uniformly susceptible to all penicillins and cephalosporins in vitro. Erythromycin treatment should not be promoted as first-line therapy because the consequent increase of bacterial resistance could create difficulty in treating penicillin-allergic patients. Because of the poor activity of trimetoprimsulfametoxazol, this drug no longer can be considered the drug of choice for the management of group A Streptococcal infections.

Adolescent↗
PubMed1997

[Role of group B streptococcus serotype V in materno-fetal infections].

BACKGROUND: The classification of serogroup B streptococci in serotype is based on the structural differences of capsular polysaccharides and on presence or absence of a protein c antigen. They are classified as Ia, Ia/c, Ib/c, II, II/c, III, IV and V. The serotype V, unknown in 1970, seems emerging, and is placed in third position of frequency in some American studies. We have therefore decided to evaluate its frequency in Paris. POPULATION AND METHODS: In a population of 137 pregnant women and 60 neonates carrying streptococcus of serogroup B, the serotype was systematically determined using the test "Group B streptococcus serotyping test" (Dako, Danemark). RESULTS: In the pregnant women population, 12% of the isolated strains were of serotype V, 26% of serotype III, 15% of serotype II, 14% of serotype Ia, and 21% could not be typed. In neonates, it represented 15% of the isolates and took place after the serotype Ia (20%), the serotype III (18%) and the serotype II (15%). None of the neonates had early- or late-onset disease. They were only colonized. Only one mother exhibited, during the per-partum, a positive blood culture with a streptococcus group B of serotype V. CONCLUSION: These results confirm, in Paris, the importance of this serotype previously observed in foreign studies. It represents 11 to 15% of the isolated streptococcus group B in the neonates and can cause early or late-onset disease. However, larger studies are needed to evaluate the exact risk of pathology for the serotype V and its significance in neonatal infectious disease.

Female↗
PubMed1988

Haemolytic streptococcus infection of chronic maxillary sinusitis. An immunological study using the skin window test.

The SWT was performed on 30 patients with chronic haemolytic streptococcus maxillary sinusitis, and 5 controls with no streptococcus in their nose and throat. Foreign and patient's own organism were used as antigen. The lymphoblastic transformation was higher in control streptococcus free patients than in chronic maxillary sinusitis, more when using foreign than patient's own organism. The failure of cellular immune response as a contributory factor to chronicity of maxillary sinusitis is discussed. The possible value of prepared foreign streptococcus vaccine in prevention and treatment is mentioned.

Adolescent↗
PubMed2004

[Fever, malaise and new onset mitral valve insufficiency. Subacute Streptococcus bovis mitral valve endocarditis ].

A 62-year-old patient with low grade fever, fatigue, arthralgia and newly discovered mitral regurgitation was diagnosed with subacute endocarditis. Streptococcus bovis grew from all six blood culture bottles. Streptococcus bovis is known to be associated with gastrointestinal neoplasias. Therefore a colonoscopy was performed and two polyps were removed. Histological analysis revealed a tubulovillous adenoma and a serrated adenoma. Colonoscopy is mandatory for all patients with Streptococcus bovis endocarditis even without any symptoms for colorectal neoplasia. The significance of Streptococcus bovis for the carcinogenesis of colorectal neoplasias and the possible alternative pathway for colorectal carcinomas through serrated adenomas will be discussed.

Diagnosis, Differential↗
PubMed2002

Intracellular and extracellular pHs of Streptococcus mutans after addition of acids: loading and efflux of a fluorescent pH indicator in streptococcal cells.

A pH-sensitive fluorescent dye, 2', 7'-bis-(2-carboxyethyl)-5 and 6-carboxyfluorescein (BCECF), was used to determine intracellular pH (pH(in)). The efflux of BCECF loaded into oral streptococcal cells was determined after incubation of the cells at 35 degrees C for 20 min in the presence and absence of glucose. In the absence of glucose, the fluorescence of intracellular BCECF in Streptococcus mutans, Streptococcus sanguis, Streptococcus salivarius and Streptococcus sobrinus decreased only very slightly, indicating that the dye could be useful for pH(in) determination. In the presence of glucose, however, the fluorescence decreased by 57%. Thus, the pH(in) of S. mutans cells was measured by the BCECF method in the absence of glucose at various acidic pH levels by adding lactic, acetic and hydrochloric acids to the cell suspensions. The pH(in) was almost equal to the extracellular pH (pH(out)) for pH(out) values of between 8 and 5, indicating that protons permeated easily across the S. mutans cell membrane. For pH(out) between 5 and 4, pH(in) was constant at around 5, suggesting that the cell membrane was impermeable to protons, or that a cytoplasmic buffering system functioned. pH(in) decreased at pH(out) values of < 4. The constant pH(in) at acidic pH(out) levels could protect intracellular components, such as proteins, against acidification by sugar fermentation.

Acetic Acid↗
PubMed1996

Disruption of the gene encoding penicillin-binding protein 2b (pbp2b) causes altered cell morphology and cease in exopolysaccharide production in Streptococcus thermophilus Sfi6.

Genetic and biochemical analysis of exopolysaccharide (EPS) production in lactic acid bacteria has been a growing field of interest in the food industry. We previously identified and characterized a gene cluster composed of 13 genes (epsA to epsM) responsible for EPS production in Streptococcus thermophilus Sfi6. Here we report one further gene, pbp2b, that is connected to EPS production. Mutants with a gene disruption in pbp2b were no longer able to produce EPS, exhibited a reduced growth-rate, and their cell morphology was altered. The predicted gene product showed significant homology to the class B penicillin-binding proteins 2b of Streptococcus pneumoniae, Streptococcus sanguis and Streptococcus mitis involved in peptidoglycan synthesis. Upstream of pbp2b, we further identified two genes which showed significant homology to the E. coli folD and urfl, which is an unidentified open reading frame presumed to be involved in DNA repair. Downstream of pbp2b, we identified a gene that showed homology to the Bacillus subtilis and the Escherichia coli recM or recR which, respectively, are involved in the methyl-dependent DNA mismatch repair. In S. thermophilus, pbp2b and recM were transcribed from their own promoters as monocistronic mRNAs and are therefore organized as independent transcriptional units.

Amino Acid Sequence↗
PubMed1999

Identification and characterization of a Streptococcus pyogenes ABC transporter with multiple specificity for metal cations.

Metal ions are crucial trace elements for bacteria infecting the human host. The LraI (lipoprotein receptor-associated antigen I) transporter in Streptococcus spp. belongs to the superfamily of ABC transporters. The transporter consists of a lipoprotein, an ATP-binding protein and a hydrophobic integral membrane protein. Here, we describe a new member of the LraI family in the important human pathogen Streptococcus pyogenes. The system was identified in silico by analysis of the S. pyogenes Genome Sequencing Project. The S. pyogenes operon exhibits an atypical organization compared with equivalents in other Streptococcus spp. The presence and atypical organization of the operon was verified in a number of S. pyogenes strains of different serotypes. Transcriptional analysis of the LraI operon demonstrates a polycistronic transcription attenuated by a stable stem-loop structure, which allows the lipoprotein to be expressed in larger quantities than the other two components. The localization of the native lipoprotein at the bacterial surface was shown by proteolytic digestion of S. pyogenes bacteria and NH2-terminal sequencing of a released lipoprotein fragment. Recombinant lipoprotein was expressed as a GST fusion protein, and studies of molecular interactions with metal radioisotopes demonstrated that the protein has affinity for Zn(II), Fe(III) and Cu(II). Zn(II) and Cu(II) were found to compete for the same binding site, whereas Fe(III) uses a second site. Also, proton-induced X-ray analysis of lipoprotein samples identified iron, copper and zinc. Finally, a mutant strain lacking a functional mtsABC operon was generated and showed reduced uptake of 55Fe and 65Zn compared with the wild-type strain. The operon encoding this novel ABC transporter with multiple specificity for metal cations is designated mtsABC, for metal transporter of Streptococcus.

ATP-Binding Cassette Transporters↗
PubMedDate not supplied

Inhibitory effects of MoAbs against a surface protein antigen in real-time adherence in vitro and recolonization in vivo of Streptococcus mutans.

A surface protein antigen (PAc) of Streptococcus mutans, particularly the A-region of the molecule, has been reported to interact with salivary components on the tooth surface. It might be a candidate antigen inducing the production of antibodies against the adherence of S. mutans to the tooth surface. We investigated the effects of monoclonal antibodies (MoAbs) obtained by immunization of synthetic PAc peptides that completely correspond to the amino acid sequence of part of the A-region. These MoAbs recognize several core B-cell epitopes in the sequence. Two (KH5 and SH2) of these antibodies reacted with both S. mutans and Streptococcus sobrinus, but not with Streptococcus sanguis, Streptococcus salivarius, Porphyromonas gingivalis or Lactobacillus casei. They clearly inhibited the real-time adherence of S. mutans to salivary components in a biosensor. KH5, which showed a real-time inhibition (71%), also significantly prevented the recolonization of S. mutans on the tooth surface in rats. These results suggested that the core B-cell epitope (-Y---L--Y----) recognized by KH5 was the essential sequence in the antigenic epitopes of PAc protein recognized specifically by the inhibitory antibody. Therefore, the amino acid residues were found to be important in the initial attachment of S. mutans to the tooth surface. These results provide for the mechanism of PAc molecule in the initial attachment of S. mutans on the tooth surface and more effective designs for the removal of S. mutans and S. sobrinus from the oral cavity.

Adhesins, Bacterial↗
PubMed1998

Concepts and controversies in the management of group B streptococcus during pregnancy.

BACKGROUND: Group B beta-hemolytic streptococcus colonizes 20 percent of pregnant women. Intrapartum fetal colonization leads to invasive disease in 1 to 2 infants of every 1000 births in the United States, and has a mortality of approximately 6 percent. Several protocols using intrapartum chemoprophylaxis have been devised to improve management of the disease, but confusion continues about details and implementation. This review examined the clinical issues, current management protocols, and advantages and disadvantages of these protocols for group B streptococcus. METHODS: We reviewed the literature and described the epidemiology, detection methods, risk factors, neonatal disease potential of group B streptococcus, and the historical development of management protocols. Two current alternatives, the American College of Obstetricians and Gynecologists' risk-based protocol and the Centers for Disease Control and Prevention's screening-based protocol, are described and compared. RESULTS: The risk-based protocol does not entail antepartum screening, but treats women with certain risk factors during labor. The screening-based protocol includes cultures at 35 to 37 weeks' gestation, and offers intrapartum prophylaxis to all women with positive cultures. Uncultured women with risk factors are treated. Both protocols involve high rates of intrapartum antibiotic use and both may significantly lower rates of neonatal group B streptococcus sepsis (screening-based more than risk-based for both). The risk-based approach is simpler than the screening-based approach. CONCLUSIONS: Practitioners should select one of the two protocols and use it consistently. The differences in efficacy are small; a practitioner may not see a difference in outcomes over the course of his or her career, although more antibiotics will be administered using the screening-based approach.

Anti-Bacterial Agents↗
PubMed2003

Taking antenatal group B Streptococcus seriously: women's experiences of screening and perceptions of risk.

BACKGROUND: Early-onset group B streptococcal disease is a serious cause of neonatal morbidity and mortality. Although screening protocols for group B streptococcus are common, little is known of women's perceptions of this screening and the disease itself. The purpose of this study was to gain an understanding of women's experiences, knowledge, and perceptions about this bacteria and its screening. METHODS: Nine focus group interviews with 35 women explored their experiences and understanding of group B streptococcus screening. Transcribed interview data were interpreted to identify and articulate the women's experiences. RESULTS: Most women had little knowledge or understanding of group B streptococcus, obtaining their information largely from the stories or experiences of friends or family. Women struggled to understand the meaning and implications, both physical and "moral," of the disease for their baby and for themselves, clearly indicating both the subjective and statistical importance of the concept of risk for pregnant women. CONCLUSIONS: Group B streptococcus continues to be poorly understood by pregnant women who try to understand and weigh up its risks and implications so as to make the best decisions about screening. The women participated in screening ultimately, however, since it was seen to be patently "best for baby," relatively easy for them to undergo, and part of routine antenatal care.

Adult↗
PubMed1988

Immunization of pregnant women with a polysaccharide vaccine of group B streptococcus.

Immunization of pregnant women with a polysaccharide vaccine of group B streptococcus is a promising strategy for the prevention of perinatal infections caused by group B streptococci. To explore the feasibility of this strategy, we vaccinated 40 pregnant women at a mean gestation of 31 weeks with a single 50-microgram dose of the Type III capsular polysaccharide of group B streptococcus. The only adverse effect detected was a mild local reaction in nine women (22 percent). Of the 35 women with low or unprotective antibody levels before immunization (less than 2 micrograms per milliliter), 20 (57 percent) responded to the vaccine. The geometric mean antibody level rose from 1.3 to 7.1 micrograms per milliliter four weeks after vaccination (P less than 0.02), and these levels persisted at delivery and three months post partum. Sixty-two percent of the vaccine-induced immunoglobulin in the mothers was IgG, which readily crosses the placenta. Infant antibody levels in cord serum correlated directly with maternal antibody levels at delivery (r = 0.913, P less than 0.001). Of the 25 infants born to women who responded to the vaccine, 80 percent continued to have protective levels of antibody at one month of age and 64 percent had protective levels at three months. Serum samples from infants with greater than or equal to 2 micrograms of antibody to Type III group B streptococcus per milliliter uniformly promoted efficient opsonization, phagocytosis, and bacterial killing in vitro of Type III strains. This effect could be mediated exclusively by the alternative complement pathway. Although this vaccine with an overall response rate of 63 percent is not optimally immunogenic, we conclude that maternal immunization is feasible and can provide passive immunity against systemic infection with Type III group B streptococcus in the majority of newborns. Larger trials with better vaccines will be required to evaluate the safety and clinical effectiveness of this strategy.

Adult↗
PubMed2002

Exploring the pathogenesis of necrotizing fasciitis due to Streptococcus pneumoniae.

Monobacterial necrotizing fasciitis is a rare form of soft tissue infection usually caused by the group A beta-hemolytic Streptococcus. Soft tissue infection is an uncommon clinical manifestation of invasive disease due to Streptococcus pneumoniae. We describe 3 cases of pneumococcal necrotizing fasciitis and explore potential pathogen-specific mechanisms of pathogenesis. The clinical characteristics of necrotizing fasciitis due to S. pneumoniae and group A beta-hemolytic Streptococcus appear to overlap. The similarities include predominant occurrence in elderly adults with underlying chronic illness, predilection for lower extremity infection, progression to toxic shock-like syndrome and a high case fatality rate. No DNA fragments corresponding to speA, speB or speC were amplified by PCR from the 3 pneumococcal isolates. Western immunoblot revealed no evidence of SpeA, SpeB or SpeC protein expression. Evaluation for protease production and cytotoxicity was unrevealing. The similar clinical presentation of pneumococcal necrotizing fasciitis to the disease caused by the group A beta-hemolytic Streptococcus has important therapeutic implications. The molecular mechanisms underlying the pathogenesis are unclear. Prospective population-based studies are required to define the epidemiology of this infection.

Aged↗
PubMed2004

The effect of dietary fish oil on survival after infection with Klebsiella pneumoniae or Streptococcus pneumoniae.

Dietary fish oil is believed to have a beneficial effect in various infections and in autoimmune disorders. This effect may correspond to an altered immune response. In order to discover whether the effect of dietary fish oil is different in various infections, we studied the survival of mice fed fish oil or corn oil supplemented diets and infected in the lungs with either Klebsiella pneumoniae or Streptococcus pneumoniae. 120 NMRI mice were divided into 4 groups, of which 2 groups were fed a fish oil supplemented diet and 2 a corn oil supplemented diet. After 6 weeks the mice were infected in the lungs with Klebsiella pneumoniae (fish oil groups and corn oil groups) or with Streptococcus pneumoniae serotype 3 (both groups). The survival rate was monitored. The experiment was performed twice. The survival of the mice fed fish oil enriched diet and infected with Klebsiella pneumoniae was significantly better compared with the mice fed corn oil enriched diet (p = 0.0001 and p = 0.0013). No difference was found between the mice fed corn oil enriched diet or fish oil enriched diet and infected with Streptococcus pneumoniae serotype 3 (p = 0.74 and p = 0.15). Our results indicate that dietary fish oil has a beneficial effect on survival of mice after experimental pneumoniae when infected with Klebsiella pneumoniae, but not after infection with Streptococcus pneumoniae serotype 3.

Animals↗
PubMed1994

The adherence of three Streptococcus bovis strains to cells of rumen epithelium primoculture under various conditions.

Three Streptococcus bovis strains were tested in biotype assay and examined for the adherence to cells of rumen epithelium primoculture. The adherence pattern of ruminal streptococci in phosphate buffered saline at pH values ranging from 4.1 to 8.5 was determined. Our isolates of Streptococcus bovis strains adhered best at pH 7.0-7.3. To characterize the adhesive determinants, the bacterial cells were exposed to various treatments. Protease treatment dramatically decreased the adherence of all Streptococcus bovis strains, thus suggesting that the determinants responsible for the adherence are largely proteinaceous. Carbohydrates could be also significantly involved in the active sites of bacterial surface because metaperiodate-treated cells adhered much more poorly than control, sodium iodate-treated cells. Addition of carbohydrates (lactose, maltose and saccharose) had no significant effect on the adherence of Streptococcus bovis strains although a slight decrease in the adhesion was detected.

Animals↗