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PubMed2002

Identification of sialyltransferases of Streptococcus agalactiae.

Group B streptococci, Streptococcus agalactiae, produce high-molecular-weight polysaccharides containing N-acetylneuraminic acid. Although the type-specific capsular polysaccharide (CP) synthesis (cps) genes of several S. agalactiae strains have been extensively analyzed, to date, no sialyltransferase activity has been detected from any gene product of the cps gene cluster. Among the cps genes, the cpsK gene products of S. agalactiae types la and Ib showed weak similarity to several bacterial sialyltransferases. In this study, the cpsIaK and cpsIbK gene products were found to show sialyltransferase activity specific for lacto-N-neotetraose and lacto-N-tetraose, respectively. This acceptor specificity seems to reflect the respective CP structure, since the repeating unit of type la CP is sialyllacto-N-neotetraose and that of type Ib CP is sialyllacto-Ntetraose. We also found that the C-terminal regions of CpsKs were almost completely conserved in various S. agalactiae strains.

Journal Article↗
PubMed1995

[Osteoarticular infections caused by Streptococcus agalactiae. Report of 4 cases].

BACKGROUND: Streptococcus agalactiae (group B streptococcus) is a rare etiology of osteoarticular infection in adults. In a literature review (Medline-Embase plus) up until may 1994, we have found only 51 cases. In most patients, diabetes mellitus, liver disease or long-term steroid therapy were documented. METHODS: Four adult patients with osteoarticular infection due to S. agalactiae from two Galician hospitals were studied from January 1988 to October 1994: prepatellar bursitis (one case), septic monoarthritis (2 cases) and psoas abscess associated to cervical spondylodiscitis and oligoarthritis (left sternoclavicular and left hip joints). RESULTS: In the first patient, a young woman with prepatellar bursitis, a previous local trauma was recorded. The second case, a man with septic arthritis of right knee, had degenerative disease of the knees and a prostatic adenocarcinoma. In the third patient, a diabetic woman with septic arthritis of the left shoulder, vulvovaginitis due to Candida albicans was found. The last patient suffered vertebral osteomyelitis of the cervical spine (C3-C4), arthritis of the left sternoclavicular and hip joints and abscess of the ipsilateral psoas. The evolution was favourable in the four cases. CONCLUSIONS: Although uncommon, osteomyelitis and arthritis caused by group B streptococcus should be considered as opportunistic pathogen in adults with debilitating conditions. Early recognition and prompt institution of adequate therapy can help avoid joint destruction and severe complications.

Adult↗
PubMed2006

Streptococcus agalactiae infections in non-pregnant adults: single center experience of a growing clinical problem.

BACKGROUND: Group B beta-hemolytic streptococcus (Streptococcus agalactiae) has been traditionally considered a major pathogen in neonates and pregnant women. However, there is accumulating concern about its significance in non-pregnant adults too. MATERIAL/METHODS: To study Streptococcus agalactiae infections in non-pregnant adults in a 354-bed general tertiary center in Athens, Greece, we analyzed retrospectively collected data from patients with Streptococcus agalactiae isolates during a 5-year period. RESULTS: Sixty-nine strains were isolated from specimens of 65 non-pregnant adults (42 women and 23 men). Thirty-four of them were managed as inpatients and 31 as outpatients. Mean age of the 34 inpatients was 57.7 (range 18-84) years. Nineteen (17 women and 2 men) of the 34 inpatients had the organism isolated from urine. Thirteen of these 19 (68.4%) patients had clinical evidence of urinary tract infection (UTI). Streptococcus agalactiae infections were diagnosed in 26 of 34 inpatients. Besides the 13 inpatients with an UTI, 2 had bacteremia of unknown origin, 2 pneumonia, 2 erysipelas, 1 spondylodiscitis, 1 peritonitis, 2 prostatitis, 1 perirectal abscess, 1 testicular abscess, and 1 diabetic foot infection. Underlying conditions of the 26 inpatients possibly predisposing to infections were neoplasia, diabetes mellitus, heart disease, splenectomy, and corticosteroid treatment. CONCLUSIONS: In keeping with results from other recent studies Streptococcus agalactiae was isolated more frequently than previously believed from non-pregnant adults in our study. In addition, our data suggest that Streptococcus agalactiae may be an underestimated cause of UTI in non-pregnant women.

Adolescent↗
PubMed1976

Infection with Streptococcus agalactiae in a London hospital.

Streptococcus agalactiae is presently the commonest beta-haemolytic streptococcus isolated from clinical material in this hospital. Between October 1974 and March 1975, 81 patients with such infections were seen. Seventeen had urinary tract infections, six had septicaemia, and one neonate had meningitis. Three of those with septicaemia were neonates and two died. The organism was also found to be a cause of pyogenic skin conditions in five patients. Isolates from throat swabs in 12 patients, from sputum in four, and from the female genital tract in 18 were considered part of the normal flora. Human strains of Str. agalactiae were found to be biochemically different from animal strains.

Adult↗
PubMed2006

Abundance of the delta subunit of RNA polymerase is linked to the virulence of Streptococcus agalactiae.

Group B streptococcus (GBS) remains a major cause of morbidity and mortality among newborn children. The bacterium is a commensal organism colonizing the rectum and the gastrointestinal and urogenital tracts of adults, but it can be transmitted to neonates by an ascending infection of the maternal genital tract or during parturition. We previously reported that a transposon insertion disrupting rpoE resulted in the decreased survival of the mutant in the neonatal rat sepsis model of GBS infection. rpoE encodes the delta protein, a subunit of RNA polymerase (RNAP) that has been characterized in Bacillus species. In this study, we confirm the association of the delta protein with purified GBS RNAP and show that it is expressed in strains representing all nine serotypes. Flow cytometric analysis of a reporter strain containing a transcriptional fusion of the rpoE promoter to gfp revealed that, in vitro, this gene is continuously expressed. Analysis of delta expression in the transposon mutant by quantitative Western blotting revealed a 10-fold reduction in relative abundance (which was linked to the attenuation in virulence that was observed for this mutant) compared to that for the wild-type strain. These data suggest that a minimum intracellular concentration of delta is necessary for this organism to cause disease.

Animals↗
PubMed2004

The novel fibrinogen-binding protein FbsB promotes Streptococcus agalactiae invasion into epithelial cells.

Streptococcus agalactiae is a major cause of bacterial sepsis and meningitis in human newborns. The interaction of S. agalactiae with host proteins and the entry into host cells thereby represent important virulence traits of these bacteria. The present report describes the identification of the fbsB gene, encoding a novel fibrinogen-binding protein that plays a crucial role in the invasion of S. agalactiae into human cells. In Western blots and enzyme-linked immunosorbent assay (ELISA) experiments, the FbsB protein was demonstrated to interact with soluble and immobilized fibrinogen. Binding studies showed the N-terminal 388 residues of FbsB and the Aalpha-subunit of human fibrinogen to recognize each other. By reverse transcription (RT)-PCR, the fbsB gene was shown to be cotranscribed with the gbs0851 gene in S. agalactiae. Deletion of the fbsB gene in the genome of S. agalactiae did not influence the binding of the bacteria to fibrinogen, suggesting that FbsB does not participate in the attachment of S. agalactiae to fibrinogen. In tissue culture experiments, however, the fbsB deletion mutant was severely impaired in its invasion into lung epithelial cells. Bacterial invasion could be reestablished by introducing the fbsB gene on a shuttle plasmid into the fbsB deletion mutant. Furthermore, treatment of lung epithelial cells with FbsB fusion protein blocked S. agalactiae invasion of epithelial cells in a dose-dependent fashion. These results suggest an important role of the FbsB protein in the overall process of host cell entry by S. agalactiae.

Bacterial Adhesion↗
PubMed2026

Drug-resistant genes, virulence characteristics, and molecular typing of clindamycin-resistant Streptococcus agalactiae in late pregnancy.

BACKGROUND: Streptococcus agalactiae increases the risk of adverse pregnancy outcomes and neonatal infections. Clindamycin is a key alternative for intrapartum prophylaxis in penicillin-allergic women, but the prevalence of clindamycin-resistant S. agalactiae is increasing, posing a significant clinical challenge. METHODS: A total of 178 strains isolated from tertiary hospitals in Jinan and Qingdao, Shandong Province, China, were characterized using antimicrobial susceptibility testing, whole-genome sequencing, multilocus sequence typing, serotyping, and analysis of resistance and virulence genes. RESULTS: All strains were susceptible to penicillin, ampicillin, linezolid, vancomycin, and tigecycline. In contrast, resistance rates to erythromycin, levofloxacin, and tetracycline were 95.5%, 60.1%, and 56.7%, respectively. Six serotypes and 15 sequence types belonging to eight clonal complexes were identified. Notable regional differences were observed. The Ib-ST10-CC12 lineage dominated in Jinan, whereas V-ST529-CC327 was predominant in Qingdao. The resistance gene mreA was ubiquitous (100%), followed by ermB (80.3%). The key virulence genes cylE, hylB, and pavA, were detected in all strains. fbsA (99.4%), the alpha protein family (98.9%), cfb (98.3%), the Pilus Island gene cluster (94.9%), and lmb (92.7%) were also highly prevalent. The two major clindamycin resistance genes, erm and lnuB, exhibited distinctly different enrichment patterns among S. agalactiae clonal complexes, despite a certain overlap in CC19 and CC327. Specifically, erm was significantly enriched in CC12 (serotype Ib), CC19 (III/V), and CC327 (III/V). In contrast, lnuB was predominantly restricted to CC19 and CC327, where it defined a unique phylogenetic subcluster. Significant differences in resistance and virulence gene profiles were observed across different clonal complexes. CONCLUSION: Clindamycin-resistant S. agalactiae in late-pregnancy women in Shandong Province, China exhibits a broad resistance spectrum, diverse molecular types, and significant regional heterogeneity. These findings underscore the need for continued surveillance and region-specific strategies for preventing neonatal S. agalactiae infections.

Humans↗
PubMed2004

Surface proteins of Streptococcus agalactiae and horizontal gene transfer.

Streptococcus agalactiae is responsible for serious infectious diseases in neonates, immuno-compromised adult patients and causes bovine mastitis in animal hosts. Genome sequencing projects revealed strong indications for horizontal gene transfer events leading to virulence acquisition and genetic diversity in this species. Bacterial surface proteins establish the first contact with host tissues and represent interesting targets for the exchange of virulence properties among different streptococci. This review will focus on horizontal gene transfer events in characterized S. agalactiae surface proteins, mobile genetic elements adjacent to the corresponding genes and will discuss potential mechanisms of transfer.

Adhesins, Bacterial↗
PubMed2004

The fibrinogen receptor FbsA promotes adherence of Streptococcus agalactiae to human epithelial cells.

Streptococcus agalactiae is a major cause of bacterial pneumonia, sepsis, and meningitis in human neonates. During the course of infection, S. agalactiae adheres to a variety of epithelial cells but the underlying mechanisms are only poorly understood. The present report demonstrates the importance of the fibrinogen receptor FbsA for the streptococcal adherence and invasion of epithelial cells. Deletion of the fbsA gene in various S. agalactiae strains substantially reduced their binding of soluble fibrinogen and their adherence to and invasion of epithelial cells, indicating a role of FbsA in these different processes. The adherence and invasiveness of an fbsA deletion mutant were partially restored by reintroducing the fbsA gene on an expression vector. Heterologous expression of fbsA in Lactococcus lactis enabled this bacterium to adhere to but not to invade epithelial cells, suggesting that FbsA is a streptococcal adhesin. Flow cytometry experiments revealed a dose-dependent binding of FbsA to the surface of epithelial cells. Furthermore, tissue culture experiments exhibited an intimate contact of FbsA-coated latex beads with the surfaces of human epithelial cells. Finally, host cell adherence and invasion were significantly blocked in competition experiments with either purified FbsA protein or a monoclonal antibody directed against the fibrinogen-binding epitope of FbsA. Taken together, our studies demonstrate that FbsA promotes the adherence of S. agalactiae to epithelial cells but that FbsA does not mediate the bacterial invasion into host cells. Our results also indicate that fibrinogen-binding epitopes within FbsA are involved in the adherence of S. agalactiae to epithelial cells.

Bacterial Adhesion↗
PubMed2003

Clinical profile of Streptococcus agalactiae native valve endocarditis.

BACKGROUND: Streptococcus agalactiae is an unusual pathogen in adults who are not pregnant. S agalactiae endocarditis is a poorly defined entity because it is uncommon; in contrast to other streptococcal endocarditis, it bears a high mortality rate. The aim of this study was to define its clinical, prognostic, and therapeutic profile on the basis of a series of 9 consecutive patients. METHODS: We conducted a prospective and multicenter study of patients with infectious endocarditis in which 310 episodes were included. RESULTS: S agalactiae grew in 9 patients (3%) who had no valve prosthesis. All patients except 1 had underlying diseases, and all patients had serious complications; the most common complications were major emboli, heart failure, and shock. The valve affected was the mitral valve in 4 patients, the aortic valve in 2 patients, both the mitral and aortic valves in 2 patients, and the tricuspid valve in 1 patient. All episodes were on native valves. Vegetations tended to be large (maximal diameter >10 mm in all patients), very mobile, and pedunculated. An abscess was found in 2 patients, and a perforation of the valve developed in 3 patients. Five patients died (mortality rate, 56%), 3 of whom had received antibiotic therapy alone. The 4 patients who survived underwent combined medical-surgical therapy. CONCLUSION: S agalactiae native valve endocarditis is very aggressive, and early surgery should be considered to prevent the destruction of valves and development of serious complications.

Aged↗
PubMed1977

Streptococcus agalactiae in urinary tract infections.

Streptococcus agalactiae was found to be the cause of approximately 1% of urinary tract infections in a London teaching hospital in the 2 years studied. Of the forty-eight patients with this infection, forty-three were female. In nine patients the infection followed renal transplantation while in nine others it occurred in the presence of chronic renal failure. The rest, who included seven females who developed the infection following hysterectomies, had other clinical conditions which could have predisposed to such infections. The rarity of urinary tract infection by S. agalactiae is in contrast to the high frequency with which the organism colonizes the normal urethra. Serotypes III and II were the predominant isolates in these patients with urinary tract infections; this corresponds to the distribution of the different serotypes in the genito-urinary tract of normal individuals.

Female↗
PubMed1989

An economic justification of "blitz" therapy to eradicate Streptococcus agalactiae from a dairy herd.

Streptococcus agalactiae was identified as the cause of mastitis in a 240-cow dairy herd. Forty-five per cent of the herd had cell counts over 500,000/ml, and 28 per cent had cell counts over 1,000,000/ml. Dry cow therapy was used regularly but teat dipping had not been used for three years. The procedures at milking were modified, teat dipping was introduced, and the herd was divided into two according to cell count. The 120 cows with higher cell counts were treated with 300 mg erythromycin (Erythrocin intramammary; Sanofi Animal Health) preparation per quarter at two consecutive milkings. Towards the end of lactation, all the 90 lactating cows in the herd were again treated with erythromycin. Milk samples were collected from all the cows in the herd 12 months after the initial treatment, and S agalactiae was isolated from only one replacement heifer which had been purchased after the treatments with erythromycin. The butterfat and protein levels in the milk were compared with those of a similar, but untreated, herd for 12 months before and after therapy. The butterfat levels rose sharply after treatment, and financial assessment showed a 41 per cent return on investment in the 12 months following the treatment.

Animals↗
PubMed2000

Structural studies of streptococcus agalactiae hyaluronate lyase.

The bacteria Streptococcus agalactiae, part of normal human flora, produce an enzyme, hyaluronate lyase, which appears to contribute to the invasive capacity of this pathogen by degrading hyaluronan and chondroitin sulfates of the extracellular matrix of host tissues. The native enzyme, the product of the hylB(3502) allele, has a molecular mass of 111 kDa but undergoes an autocatalytic conversion to a smaller enzymatically active 92 kDa form. To initiate the determination of the catalytic mechanism of action of these enzymes, the 111 and 92 kDa enzymes were crystallized by a vapor-diffusion method using polyethylene glycol monomethyl ether 5000 and potassium thiocyanate as precipitating agents. The 111 kDa enzyme crystals are of poor quality and diffract X-rays to a very low resolution. However, the crystals of the truncated 92 kDa enzyme diffract X-rays to 2.1 A resolution. The crystal symmetry is C222(1) and the unit-cell parameters are a = 51.69, b = 157.03, c = 239.20 A (alpha = beta = gamma = 90 degrees ). The V(m) of 2.64 A(3) Da(-1) is consistent with the presence of one molecule of hyaluronate lyase in the asymmetric unit and a crystal solvent content of 53%. An isomorphous ethylmercuricthiosalicylic acid heavy-atom derivative diffraction data set has been obtained in order to solve the structure.

Catalysis↗
PubMedDate not supplied

[Distribution of capsular types and antimicrobial susceptibility of Streptococcus agalactiae causing infections in Argentina].

Streptococcus agalactiae is an endogenous bacterium that has emerged in the last 20 years as an etiological agent in both neonatal and perinatal infections, and in immunocompromised patients. The differentiation of the capsular polysaccharide, the presence of surface proteins c, X, R, and molecular methods allow classification in serotypes and genotypes. This identification is a useful tool for epidemiological purposes and virulence studies in this bacterium. The objective of this work was to study the serotypes and the antimicrobial susceptibility of isolates recovered from invasive diseases in different areas of Argentina. In the analyzed sample a fair predominance of Ia and III serotypes was recovered, followed by II and IV serotypes. All the isolates were found to be sensitive to penicillin. A 6% of resistance to erythromycin and a 4.5% to clindamycin were detected. In three of the isolates, constitutive MLS phenotype (resistance to macrolides, lincosamins and streptogramins) was founded, while in the remaining one, inducible MLS phenotype was detected. These results stress the importance of conducting a surveillance of the prevalent serotypes in our country with the goal of future prevention of this disease with an effective vaccine. The knowledge of the antimicrobial susceptibility profile will be also important to obtain therapeutic success in the treatment.

Argentina↗
PubMed1983

Evaluation of nine teat dip formulations under experimental challenge to staphylococcus aureus and streptococcus agalactiae.

Nine postmilking teat dips were evaluated by an experimental challenge model against either Staphylococcus aureus, Streptococcus agalactiae, or both. Formulations containing .9 and .6% sodium hypochlorite, 1% sodium dichloro-s-triazene-trione, .55% chlorhexidine gluconate, and .35% povidone iodine reduced incidence of Staphylococcus aureus infections 56.8, 28.3, 75.9, 92.5, and 77.9%. Incidence of infections with Streptococcus agalactiae was reduced 48.1 and 63.2% by 1.7 and 1% sodium dichloro-s-triazene-trione formulations. The 1% chlorhexidine gluconate and .35% povidone iodine products reduced Streptococcus agalactiae infections 71.0 and 67.0%. Three experimental 1% iodophor formulations reduced Streptococcus agalactiae infections 28.9, 44.8, and 50.7%. The experimental challenge model was refined further and provided an efficient method to determine efficacy of postmilking teat dips.

Administration, Topical↗
PubMed1987

Growth responses of Staphylococcus aureus and Streptococcus agalactiae to Corynebacterium bovis metabolites.

Staphylococcus aureus and Streptococcus agalactiae growth responses to metabolites of Corynebacterium bovis cultured in media containing polyoxyethylenesorbitan monolaurate, monooleate, or trioleate and milk were determined. Filter sterilized metabolites of 48-h C. bovis cultures in synthetic media were added to cultures of Staph. aureus and Strep. agalactiae. Staphylococcus aureus and Strep. agalactiae were inoculated into 12-h C. bovis milk cultures. Growth responses of Staph. aureus and Strep. agalactiae were not affected by C. bovis metabolites of synthetic media. Staphylococcus aureus growth was inhibited during logarithmic and stationary phases in milk containing mixed cultures of C. bovis compared with growth in pure Staph. aureus cultures. Streptococcus agalactiae growth curves were similar in pure and C. bovis mixed cultures. Fatty acid compositions were not different in sterile milk and milk containing bacterial cultures. Growth responses of Staph. aureus and Strep. agalactiae were not related to concentration of C. bovis metabolites or fatty acid content of media in which C. bovis were cultured.

Corynebacterium↗
PubMedDate not supplied

[Neonatal infection by Streptococcus agalactiae. Multicenter study in the area of Barcelona, Spain].

BACKGROUND: Streptococcus agalactiae or streptococcus group B (SGB) is the main etiologic agent of early neonatal sepsis. A multicenter study was performed with the aim of determining the incidence and characteristics of this disease in our medium and contribute the design of an adequate prevention protocol. METHODS: Ten hospitals and two primary health care centers were implicated in the study; 103 microbiology confirmed episodes of SGB neonatal sepsis (blood and/or LCR positive) were reported from 1994 to 1996. RESULTS: The incidence of early SGB neonatal sepsis was 1.48/1,000 live births with a mortality of 8.7%. The cultures, for detecting the state of the SGB carrier were performed in only 26 (25%) of the patients. At least one of the factors described for risk of perinatal SGB infection was observed in 46% of the mothers, with the most frequent being prolonged amniorrhea (26%), intrapartum fever (17%), and early delivery (14%). At the time of delivery only 10.7% of the mothers received endovenous antibiotherapy. CONCLUSIONS: From these results the following recommendations have been made: a) detection of SGB carriers by the systematic practice of blood cultures in the last weeks of gestation and b) the administration of intrapartum antibiotic prophylaxis in both early births (< 37 weeks) and in all the SGB carriers should be undertaken. With these measures we aim to decrease the neonatal infections by streptococcus group B.

Adult↗