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PubMed2002

A PCR-based method for the detection of Streptococcus agalactiae in milk.

Bovine mastitis caused by Streptococcus agalactiae is mainly subclinical and therefore can be diagnosed only in the laboratory. We developed a polymerase chain reaction (PCR)-based method for specific and sensitive detection of S. agalactiae in raw milk. The specificity of the PCR reaction is based on unique S. agalactiae DNA sequences within the 16S subunit of the rRNA genes. Two pairs of sequences were used as positive controls; general streptococci primers, which anneal to conserved areas within the 16S rRNA subunit gene, and primers, which anneal to sequences within bovine mitochondrial DNA. The method of detection includes selective enrichment of S. agalactiae in the milk sample, followed by DNA extraction using a rapid and simple procedure developed for this purpose, and specific PCR reaction with appropriate controls. The method enables the detection of one bacterium in 1 ml of raw milk. The method developed can be easily incorporated as part of routine screening of bulk milk collection tanks for early detection of infected cows in a herd.

Animals↗

PubMed2000

Complementary characterization of a hyaluronic acid splitting enzyme from Streptococcus agalactiae.

A hyaluronic acid splitting enzyme of Streptococcus agalactiae was characterized by splitting mechanism, Michaelis-constant and inhibition type for sulfated hyaluronic acid: The enzyme splits hyaluronic acid as a hyaluronate lyase [EC 4.2.2.1]. The Km = 8 x 10(-4) mg ml-1 was determined with the influence of substrate inhibition constant Kiu = 2 x 10(-6) mg ml-1. Sulfated hyaluronic acid inhibits the enzyme in a partially non-competitive way. The inhibition constant is Ki = 5.47 x 10(-4) mg ml-1. The GBS-hyaluronate lyase cleaves hyaluronic acid as an endoglycosidase. The work is related with the intention to establish a hyaluronate lyase of microbial origin as a therapeutical enzyme replacing bovine hyaluronidase.

Animals↗

PubMed1994

Purification and characterization of hyaluronidase from Streptococcus agalactiae.

Hyaluronidase from two different strains of Streptococcus agalactiae was purified and characterized. The purification was performed successively by chromatography and rechromatography on phenylsepharose, gel filtration with FPLC on Superdex G 200 and isoelectric focusing. The purified hyaluronidase had an isoelectric point of 8.75 and a molecular weight of approximately 116,000 D. It showed maximal enzyme activity at pH 6.30 and 40 degrees C. The Michaelis constant was estimated to be 8.17 x 10(-2) mg/ml. Hyaluronidase was stimulated only by Mg++ and inhibited by Zn++, Al , Cu++ and Fe++ at a final concentration of 10 mmol/l, respectively. The enzyme splitted hyaluronic acid and in low amounts dermatan sulphate and chondroitin sulphate A. Additionally, synthetic polyanions (like polymers of gentisic acid with formaldehyde and hydroxy sulphonic acid with formaldehyde) turned out to be also potent inhibitors of the enzyme.

Hyaluronoglucosaminidase↗

PubMed1997

Streptococcus agalactiae beta gene and gene product variations.

Streptococcus agalactiae (group B streptococci; GBS) are serotyped on the basis of the capsular polysaccharide antigens and subtyped on the basis of the strain-variable and surface-localised c proteins c alpha, c beta, and R proteins. This study compared c beta protein detection and the polymerase chain reaction (PCR) for beta gene detection, by examining 50 clinical GBS strains. The c beta protein was detected by antibody-based immunofluorescence in a GBS whole-cell assay and Western blotting by probing with the anti-c beta antibody or human IgA. Absorption experiments were performed to test for surface-anchoring of c beta; and bacterial supernates were examined to test for c beta production. Primers for the PCR target regions resulted in a 620-bp product that included beta gene-encoding IgA-binding domains. The results demonstrated four categories of GBS with respect to the beta gene and the c beta protein: (1) strains (16 of 50) that harboured the beta gene and regularly expressed normal surface-localised c beta with a M(r) of 120 kDa; (2) strains (5 of 50) that harboured the gene but did not express the protein; (3) strains (2 of 50) that harboured the gene but expressed a c beta that was not surface-localised and had reduced M(r); (4) strains (27 of 50) without beta gene and c beta expression. One strain amongst the third group generated a PCR product of 1330 bp. These results demonstrate considerable strain variability of the beta gene of GBS and of its product the c beta protein.

Adult↗

PubMed2002

[Clinical and demographic profile of patients with gyneco-obstetric disease colonized by Streptococcus agalactiae].

OBJECTIVE: To describe demographics and clinical features in women with vaginal colonization with Streptococcus agalactiae attended in a gyneco-obstetric hospital. METHODS: Descriptive study of 118 women with isolation of Streptococcus agalactiae in cervical swab during January 1992 to December 1998. Major patient features were obtained in retrospective revising their chart and were classified in demographic, gyneco-obstetrical and clinical characteristics. Statistical analyses were performed with descriptive statistics using central tendency measurements and dispersion, frequencies, rates and proportions with all different variables. RESULTS: Mean age was 31 +/- 11 years; 44 (37.3%) received attention because of sterility, 37 (31.4%) were pregnant, 26 (22%) had any other gynecological disease and, 11 (9.3%) were in a group of high pregestational risk. One hundred eleven (94.1%) were sexually active, starting at a mean age of 20.9 +/- 4.3. GBS was the only microorganism isolated in 70 patients (59.3%). A concomitant cervicovaginal infection was identified in 22 (18.6%) patients. A sexual transmitted disease was present in 25 (21.2%) patients, with isolation of human papilomavirus (HPV), M. hominis, C. trachomatis y T. vaginalis. Fifty-five patients had a concomitant illness: 24 with endocrine disease, 12 cardiovascular pathology and 10 with oncologic disease. CONCLUSIONS: Vaginal colonization of mexican women by GBS is low. However, clinical and demographics characteristics are required to identify these women easily, because of the importance of maternal and infant infection by this organism.

Adolescent↗

PubMed1983

Germicidal teat dip in a herd with low prevalence of Streptococcus agalactiae and Staphylococcus aureus mastitis.

Effectiveness of an iodophor teat dip in reducing new intramammary infection and clinical mastitis was tested in a herd free of Streptococcus agalactiae and with a low prevalence of Staphylococcus aureus infections. In this 6-mo study with an average of 152 lactating cows on trial on sampling dates, right rear and left front teats were dipped after each milking while right front and left rear teats were undipped controls. Teat dipping significantly reduced new infections by Staphylococcus aureus, streptococci (other than Streptococcus agalactiae), coagulase-negative staphylococci, and Corynebacterium bovis and reduced clinical cases caused by infections established during the trial. However, the dip did not reduce new infections or clinical mastitis caused by coliform bacteria. Therefore, use of a germicidal dip is recommended for herds with a low prevalence of Streptococcus agalactiae and Staphylococcus aureus, but the practice should not be expected to control coliform mastitis.

Administration, Topical↗

PubMedDate not supplied

[Streptococcus agalactiae in pregnant women. Prevalence at the Posadas Hospital].

Streptococcus agalactiae (Lancefield group B Streptococcus), is the most frequent microorganism involved in neonatal infections through the mother-fetus vertical transmission. It is also responsible for infections in pregnant women, and adults with underlying diseases. The objective of this work was to know the S. agalactiae carrier prevalence in pregnant women who attended to Posadas Hospital, and to study the susceptibility pattern of the isolates to penicillin, erythromycin and clindamycin. From 1203 pregnant women studied, S. agalactiae was recovered in 113, which means a prevalence of 9.39%. Antimicrobial susceptibility was tested to 87 isolates. All of them were susceptible to penicillin, and only 2 isolates were resistant to erythromycin and clindamycin (constitutive MLS mechanism). We emphasize the importance of knowing these last resistance, in the case of beta-lactam antibiotics allergic women.

Adolescent↗

PubMed1987

The economic benefit of treating subclinical Streptococcus agalactiae mastitis in lactating cows.

The economic benefits of treating lactating cows for Streptococcus agalactiae mastitis were studied at a large (689 milking cows) central California dairy. Postcure milk production of case cows (infected, treated, and cured) was compared with production of paired control cows (uninfected) and was matched for yield, days in milk, days in gestation, and parity. A simulation was used to plot expected lactation curves for mastitic cows (infected, not treated) with characteristics similar to those of each control cow, and these curves were compared with actual case-cow lactation curves. The difference in actual and expected production was used to calculate net economic benefits of treatment. Comparison of expected with actual production indicated a net benefit from treatment of $396/cow for cows treated in early lactation and $237 for cows treated in midlactation, but a net loss of $55 for cows treated in late lactation. Lactation number did not have a significant impact on economic benefits of treatment. In contrast to other studies indicating no economic benefit from treating mastitis during lactation, this study's positive results may have been attributable to the high cure rate (98%) and the subclinical form of mastitis being treated. Streptococcus agalactiae mastitis treatment during early and midlactation would appear to be an economically justifiable option for dairy managers.

Animals↗

PubMed2001

Wound erysipelas following appendectomy caused by group B beta-hemolytic Streptococcus (Streptococcus agalactiae).

BACKGROUND: Case description of a patient who developed erysipelas of the surgical wound following appendectomy for acute appendicitis, and literature review of invasive group B streptococcal infections. METHODS: A 65-year-old man with perforated appendicitis underwent urgent appendectomy and drainage. Antibiotic prophylaxis with tobramycin (100 mg) and metronidazole (500 mg) was administered. At surgery, a phlegmon was identified with free perforation of the appendix and purulent peritoneal fluid. Appendectomy, irrigation with 0.9% NaCl solution, and drainage with a Silastic closed-suction drain was performed. A literature search in all languages was performed using MEDLINE, using the search terms surgical site infection, wound infection, group B streptococcus, Streptococcus agalactiae, necrotizing fasciitis, and postoperative infection. RESULTS: Erysipelas of the surgical wound developed on the fourth postoperative day. Intravenous penicillin and amoxicillin/clavulanic acid were administered empirically. Culture of the wound drainage identified Streptococcus agalactiae and a few colonies of Escherichia coli. The broad-spectrum antibiotic was discontinued, and a 10-day course of penicillin was completed. CONCLUSIONS: Erysipelas of the surgical wound is unusual, and infection with group B streptococci is rare compared with infection by group A streptococci. Streptococcus agalactiae is recognized to be increasingly virulent, with an increasing predilection for bacteremic infections in healthy hosts. Although Streptococcus agalactiae remains highly susceptible to antimicrobial agents effective against gram-positive cocci, the changing epidemiology and potentially invasive nature of these infections should have clinicians alert to the possibility of infection caused by group B streptococci.

Aged↗

PubMed2002

Genome sequence of Streptococcus agalactiae, a pathogen causing invasive neonatal disease.

Streptococcus agalactiae is a commensal bacterium colonizing the intestinal tract of a significant proportion of the human population. However, it is also a pathogen which is the leading cause of invasive infections in neonates and causes septicaemia, meningitis and pneumonia. We sequenced the genome of the serogroup III strain NEM316, responsible for a fatal case of septicaemia. The genome is 2 211 485 base pairs long and contains 2118 protein coding genes. Fifty-five per cent of the predicted genes have an ortholog in the Streptococcus pyogenes genome, representing a conserved backbone between these two streptococci. Among the genes in S. agalactiae that lack an ortholog in S. pyogenes, 50% are clustered within 14 islands. These islands contain known and putative virulence genes, mostly encoding surface proteins as well as a number of genes related to mobile elements. Some of these islands could therefore be considered as pathogenicity islands. Compared with other pathogenic streptococci, S. agalactiae shows the unique feature that pathogenicity islands may have an important role in virulence acquisition and in genetic diversity.

Amino Acid Sequence↗

PubMed1976

[Sensitivity of Streptococcus agalactiae and Staphylococcus aureus strains to antibiotics in Slovia during 1975].

The sensibility of 3100 Streptococcus agalactiae strains and 600 Staphylococcus aureus strains to antibiotics was examined in 1975 in the veterinary institute of the Slovak Socialist Republic by the plate diffusion test. The strains were collected from the dairy cow's milk samples. Of the Streptococcus agalactiae strains there were sensible 100% to ampicillin, 99.06% to chloramphenicol, 98.13% to erythromycin, 96.12% to oxytetracycline, 91.11% to bacitracin, 58.12% to penicillin, 23.92% to neomycin, 17.78% to streptomycin. Of the Staphylococcus aureus strains there were sensible 97.48% to erythromycin, 97.14% to chloramphenicol, 95.15% to ampicillin, 94.81% to bacitracin, 93.26% to oxytetracycline, 92.49% to neomycin, 85.37% to streptomycin and 46.02% to penicillin. The results are being more thoroughly analysed and compared in the dicussion.

Animals↗

PubMed1993

Activation of the classical pathway of complement by binding of bovine lactoferrin to unencapsulated Streptococcus agalactiae.

The ability of lactoferrin (Lf) bound to Streptococcus agalactiae to interfere with the deposition of complement components on the bacterial surface was investigated by enzyme-linked immunosorbent assay (ELISA). By using a strain of S. agalactiae which activates the alternative pathway of complement in the absence of antibodies, it was found that pretreatment of bacteria with Lf shortened the lag phase preceding the deposition of C3 on bacteria. The kinetics of C3 deposition was comparable to that obtained by adding antibodies against S. agalactiae to agammaglobulinaemic precolostral calf serum (PCS) heated at 56 degrees for 3 min to inactivate the alternative pathway. Accelerated C3 deposition did not occur in the absence of Ca2+ ions. Deposition of C4 on bacteria occurred only when either antibodies or Lf were added to PCS. These results demonstrate that the interaction of lactoferrin with bacteria activated the classical pathway of complement in the absence of antibodies. The binding of purified C1q to bacteria was promoted in a dose-dependent manner by Lf, suggesting that recruitment of classical pathway of complement resulted from the interaction of C1q with Lf adsorbed to the bacterial surface. Phagocytosis of bacteria opsonized with heated PCS (at 56 degrees for 3 min) and Lf was comparable to that occurring in the presence of heated PCS and antibodies. In conclusion, Lf was able to substitute for antibodies in order to activate the classical pathway of complement and to opsonize unencapsulated S. agalactiae efficiently.

Antibodies, Bacterial↗

PubMed2006

In vitro antimicrobial activity of benzalkonium chloride against clinical isolates of Streptococcus agalactiae.

OBJECTIVES: Despite antibiotic prophylaxis for at-risk mothers during labour and delivery, Streptococcus agalactiae (group B Streptococcus; GBS) still causes substantial morbidity and mortality among newborns. In addition to the well-known side effects of the administration of antibiotics, resistance to drugs recommended for penicillin-allergic pregnant women, such as erythromycin and clindamycin, has increased, thus raising concern about the possibility of inadequate prophylaxis. On this basis we evaluated the antimicrobial activity of benzalkonium chloride against GBS, which has been described as an antimicrobial agent for the topical treatment of vaginal infections. METHODS: A total of 52 GBS from pregnant women have been studied. The capacity of benzalkonium chloride as well as of penicillin, erythromycin, clindamycin, vancomycin, chloramphenicol and tetracycline to inhibit GBS was evaluated using broth macrodilution and microdilution methods, respectively. RESULTS: While all the strains were penicillin- and vancomycin-susceptible, 19.2% were resistant to both erythromycin and clindamycin. In contrast, all GBS isolates were either inhibited or killed by benzalkonium chloride at not only low but also very similar concentrations (MIC90 = 3.12 mg/L). CONCLUSIONS: Benzalkonium chloride might represent an alternative strategy that is useful in reducing vaginal GBS colonization in pregnant women before delivery by topical treatment.

Anti-Infective Agents, Local↗

PubMed2003

Serotypes of Streptococcus agalactiae cultured from dairy milk samples in Québec.

Streptococcus agalactiae remains an important pathogen of dairy herds in Québec, but data about antigenic characteristics of this microorganism are sparse. This study was conducted to determine the variety of S. agalactiae serotypes in dairy herds in Québec. Two hundred and ninety-five isolates cultured from the milk of individual cows from 7 regions of Québec were serotyped. Sixty-two percent of the isolates were untypable. Among the 38% of typeable isolates, serotype III was found most frequently. In conclusion, the heterogeneity found among antigenic determinants of isolates from bovine milk suggests that an immunological method for the detection of S. agalactiae performed directly on bovine milk would not be a practical approach.

Animals↗

PubMed2006

Multiple interactions of FbsA, a surface protein from Streptococcus agalactiae, with fibrinogen: affinity, stoichiometry, and structural characterization.

Streptococcus agalactiae is an etiological agent of several infective diseases in humans. We previously demonstrated that FbsA, a fibrinogen-binding protein expressed by this bacterium, elicits a fibrinogen-dependent aggregation of platelets. In the present communication, we show that the binding of FbsA to fibrinogen is specific and saturable, and that the FbsA-binding site resides in the D region of fibrinogen. In accordance with the repetitive nature of the protein, we found that FbsA contains multiple binding sites for fibrinogen. By using several biophysical methods, we provide evidence that the addition of FbsA induces extensive fibrinogen aggregation and has noticeable effects on thrombin-catalyzed fibrin clot formation. Fibrinogen aggregation was also found to depend on FbsA concentration and on the number of FbsA repeat units. Scanning electron microscopy evidentiated that, while fibrin clot is made of a fine fibrillar network, FbsA-induced Fbg aggregates consist of thicker fibers organized in a cage-like structure. The structural difference of the two structures was further indicated by the diverse immunological reactivity and capability to bind tissue-type plasminogen activator or plasminogen. The mechanisms of FbsA-induced fibrinogen aggregation and fibrin polymerization followed distinct pathways since Fbg assembly was not inhibited by GPRP, a specific inhibitor of fibrin polymerization. This finding was supported by the different sensitivity of the aggregates to the disruptive effects of urea and guanidine hydrochloride. We suggest that FbsA and fibrinogen play complementary roles in contributing to thrombogenesis associated with S. agalactiae infection.

Bacterial Proteins↗

PubMed2004

Favorable outcome of infective endocarditis due to Streptococcus agalactiae after conservative treatment.

Infective endocarditis due to Streptococcus agalactiae is uncommon and carries an ominous prognosis, leading some authors to advocate early surgery. This report describes an 83-year-old woman with community-acquired infective endocarditis due to S. agalactiae. The patient, who had a history of surgery for colon cancer, presented with fever, agitation and general malaise. She achieved a favorable outcome with antibiotic treatment only. For infective endocarditis due to S. agalactiae, appropriate antimicrobial agents should be started as soon as possible, with surgery reserved for those cases of particular indication.

Aged↗

PubMed2001

Macrolide resistance gene mreA of Streptococcus agalactiae encodes a flavokinase.

The mreA gene from Streptococcus agalactiae COH31 gamma/delta, resistant to macrolides and clindamycin by active efflux, has recently been cloned in Escherichia coli, where it was reported to confer macrolide resistance (J. Clancy, F. Dib-Hajj, J. W. Petitpas, and W. Yuan, Antimicrob. Agents Chemother. 41:2719--2723, 1997). Cumulative data suggested that the mreA gene was located on the chromosome of S. agalactiae COH31 gamma/delta. Analysis of the deduced amino acid sequence of mreA revealed significant homology with several bifunctional flavokinases/(flavin adenine dinucleotide (FAD) synthetases, which convert riboflavin to flavin mononucleotide (FMN) and FMN to FAD, respectively. High-performance liquid chromatography experiments showed that the mreA gene product had a monofunctional flavokinase activity, similar to that of RibR from Bacillus subtilis. Sequences identical to those of the mreA gene and of a 121-bp upstream region containing a putative promoter were detected in strains of S. agalactiae UCN4, UCN5, and UCN6 susceptible to macrolides. mreA and its allele from S. agalactiae UCN4 were cloned on the shuttle vector pAT28. Both constructs were introduced into E. coli, where they conferred a similar two- to fourfold increase in the MICs of erythromycin, spiramycin, and clindamycin. The MICs of a variety of other molecules, including crystal violet, acriflavin, sodium dodecyl sulfate, and antibiotics, such as certain cephalosporins, chloramphenicol, doxycycline, nalidixic acid, novobiocin, and rifampin, were also increased. In contrast, resistance to these compounds was not detected when the constructs were introduced into E. faecalis JH2-2. In conclusion, the mreA gene was probably resident in S. agalactiae and may encode a metabolic function. We could not provide any evidence that it was responsible for macrolide resistance in S. agalactiae COH31 gamma/delta; broad-spectrum resistance conferred by the gene in E. coli could involve multidrug efflux pumps by a mechanism that remains to be elucidated.

Amino Acid Sequence↗

PubMed1990

Vertebral osteomyelitis secondary to Streptococcus agalactiae.

Vertebral osteomyelitis due to hematogenous seeding of Streptococcus agalactiae occurred in a 29-year-old farmer. The patient was treated with immobilization and parenteral antibiotics but developed recurrent back pain requiring a posterior spinal fusion. In a review of the literature, Group B streptococcal vertebral osteomyelitis seems not to have been previously reported in an adult.

Adult↗