[Streptococcus agalactiae (Streptococcus group B): clinical and bacteriological aspects].
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Microbial Sensitivity Tests↗
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Surface protein of a Streptococcus agalactiae isolate.
A Streptococcus agalactiae isolate of bovine origin was cultured in broth; log-phase cells were washed and radioiodinated and subsequently extracted at low pH in the presence of a nonionic detergent. A protein antigen was purified from concentrated extract by ultracentrifugation, gel filtration, and ion-exchange chromatography. The molecular weight of the protein was estimated at 31,800. The agglutinogenic character of the protein indicated its localization at the cell surface.
Antigens, Bacterial↗
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↗
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↗
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↗
Experimental infection of the bovine udder with the induced L phase of Streptococcus agalactiae.
Two out of 30 strains of Streptococcus agalactiae produced stable L phase variants when passaged on hypertonic agar containing penicillin. Streptococcal L phase variants were inoculated into six quarters of cows. The cows were observed for three months but the L phase was not reisolated and no reversion took place, the cows remaining free from streptococcal infection.
Animals↗
[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↗
[Sensitivity of Streptococcus agalactiae and Staphylococcus aureus strains to antibiotics in Slovakia during 1974].
In 1974, the State Veterinary institutes in the Slovak Socialist Republic studied the sensitivity of 4420 strains of Streptococcus agalactiae and 1056 strains of Staphylococcus aureus to eight antibiotics. The strains were isolated from milk samples obtained from dairy cows suffering from mastitis. 100 per cent of the strains of Streptococcus agalactiae was sensitive to ampicillin, 99.23% to erythromycin, 98.70% to oxytetracycline, 93.02% to bacitracin, 90.77% to chloramphenicol, 41.97% to penicillin, 12.39% to neomycin, 9.73% to streptomycin. As to the strains of Staphylococcus aureus, 98.68 were sensitive to chloramphenicol, 98.50% to ampicillin, 97.92% to erythromycin, 94.98% to oxytetracycline, 93.85% to neomycin, 92.67% to bacitracin, 87.50% to streptomycin, and 46.24% to penicillin. The results are discussed in relation to the use of antibiotics in the treatment of mastitis in dairy cows.
Animals↗
[Sensitivity of Streptococcus agalactiae and Staphylococcus aureus to antibiotics in the Slovak Socialist Republic in the year 1974].
In 1974, the State veterinary institutes in the Slovak Socialist Republic studied the sensitivity of 4420 strains of Streptococcus agalactiae and 1056 strains of Staphylococcus aureus to eight antibiotics. The strains were isolated from milk samples obtained from dairy cows suffering from mastitis. 100 per cent of the strains of Streptococcus agalactiae was sensitive to ampicillin, 99.23% to erythromycin, 98.70% to oxytetracycline, 93.02% to bacitracin, 90.77% to chloramphenicol, 41.97% to penicillin, 12.39% to neomycin, 9.73% to streptomycin. As to the strains of Staphylococcus aureus, 98.68 were sensitive to chloramphenicol, 98.50% to ampicillin, 97.92% to erythromycin, 94.98% to oxytetracycline, 93.85% to neomycin, 92.67% to bacitracin 87.50% to streptomycin, and 46.24% to penicillin. The results are discussed in relation to the use of antibiotics in the treatment of mastitis in dairy cows.
Anti-Bacterial Agents↗
Antibacterial action of lactoperoxidase-thiocyanate-hydrogen peroxide on Streptococcus agalactiae.
Antibacterial activity of lactoperoxidase (LP)-thiocyanate (SCN)-hydrogen peroxide (H2O2) on Streptococcus agalactiae requires that the three reactants must be in contact with the cells simultaneously. Small but assayable amounts of LP adsorb to the cell surface and are not removed by washing. A diffusible antibacterial product of LP-SCN-H2O2 reaction was not found under our experimental conditions. Incubation of S. agalactiae cells with LP-H2O2 and 14C-labeled sodium SCN resulted in the incorporation of SCN into the bacterial protein. Most of the LP-catalyzed, incorporated SCN was released from the bacterial protein. Most of the LP-catalyzed, incorporated SCN was released from the bacterial protein with dithiothreitol. Cells that had their membrane permeability changed by treatment with Cetab or 80% ethanol incorporated more SCN than did untreated cells, i.e., approximately 1 mol of SCN for each mol of sulfhydryl group present in the reaction mixture. Alteration of membrane permeability caused protein sulfhydryls, normally protected by the cytoplasmic membrane, to become exposed to oxidation. The results suggest the LP-H2O2-catalyzed incorporation of SCN into the proteins of S. agalactiae by a mechanism similar to that reported for bovine serum albumin. Removal of reactive protein sulfhydryls from a functional role in membrane transport and in glucolysis in a likely cause of the antibacterial effect for S. agalactiae.
Bacterial Proteins↗
Whole-genome sequence of Streptococcus agalactiae strain GIFTS31 isolated from streptococcosis-infected Nile tilapia in Bangladesh.
Streptococcus agalactiae strain GIFTS31 was isolated from a Nile tilapia infected with streptococcosis in Gazipur, Bangladesh. The draft genome of GIFTS31 comprises 2,039,674 bp with a GC content of 35% and encodes 1,957 predicted protein-coding sequences. The genome sequence provides valuable insights into the pathogenic potential of fish-associated S. agalactiae.
Streptococcus agalactiae↗
Glucose transport in Streptococcus agalactiae and its inhibition by lactoperoxidase-thiocyanate-hydrogen peroxide.
Transport of 2-deoxyglucose or glucose in Streptococcus agalactiae was strongly inhibited if the cells were first exposed to a combination of lactoperoxidase-thiocyanate-hydrogen peroxide (LP-complex). The inhibition was completely reversible with dithiothreitol. N-ethylmaleimide and p-chloromercuribenzoate inhibited sugar transport, and the inhibition was also reversible with dithiothreitol. Sodium fluoride also inhibited sugar transport. Glucolysis was completely inhibited, and dithiothreitol completely reversed the inhibition. Phosphoenolpyruvate-dependent phosphotransferase activity in S. agalactiae was not strongly inhibited by the LP-complex. Interference of the entry of glucose into cells of S. agalactiae by the LP-complex could well account for its growth inhibitory properties with this organism. The inhibition of glucose transport by the LP-complex and its reversibility with dithiothreitol suggest the modification of functional sulfhydryl groups in the cell membrane as a cause of transport inhibition.
Biological Transport, Active↗
Intramammary infections in a dairy herd with a low incidence of Streptococcus agalactiae and Staphylococcus aureus infections.
In a dairy herd with a low incidence of intrammary infections due to Streptococcus agalactiae and Staphylococcus aureus, clinical mastitis remained a serious problem despite good control of nonclinical mastitis through postmilking teat disinfection and antibiotic therapy of known infected quarters at the end of lactation. During the 2-year study, the incidence of clinical mastitis was 0.88 cases/cow-year; 32.2% were caused by streptococcal species other than Str agalactiae and 33.5% by gram-negative organisms. Among all new infections detected, 54.1% were caused by streptococcal species other than Str agalactiae and 25.7% by gram-negative bacteria. Among new infections, 41.6% occurred during the nonlactating period or within a few days of calving. Incidence of clinical mastitis was highest in the 1st month of lactation. Among 84 gram-negative infections, 42.8% were caused by Klebsiella pneumoniae, 20.2% by Escherichia coli, and 23.8% by Enterobacter spp. Among the many serotypes of K pneumoniae and E coli, none was predominant.
Animals↗
[Bacteriological characteristics of Streptococcus agalactiae. Incidence and conditions of appearance of the pigmentation. Sensitivity to antibiotics].
From a bacteriological study of 137 strains of streptococcus agalactiae, it seems that this species is perfectly defined by bacteriological tests, the most characteristic of which is hydrolysis with hippuric acid. The brown pigment of the strains, the conditions for demonstration of which are described and discussed here, may also be an important characteristic for it is rare in streptococci. The pigment was extracted, its nature and role are discussed. The sensitivity to 12 antibiotics was studied; the beta-lactamines were the most commonly active.
Aerobiosis↗
Bovine antibody against Streptococcus agalactiae, type Ia, produced by preparturient intramammary and systemic vaccination.
Four pregnant heifers were immunized by the intramammary route with killed or live Streptococcus agalactiae vaccine, and a 5th heifer was vaccinated by the intramuscular route with killed vaccine. Antibody in the colostrum from vaccinated and non-vaccinated glands was compared. Antibacterial glands was compared. Antibacterial antibody titers of the 4 immunoglobulin classes were determined by indirect fluorescent antibody assay. Although the content of immunoglobulin G1 (IgG1), IgG2, and IgM in the colostrum from the vaccinated glands was not substantially different from the nonvaccinated glands, IgA content was considerably greater in the former. Antibody specific to S agalactiae was isolated from all colostrum samples. The mouse passive protection test and Ouchterlony analysis were used to demonstrate the presence of type-specific antibody to Ia strain used for vaccination. The passive mouse protection test also was useful to compare the protective capacity of specific S agalactiae, type Ia, antibodies of immunoglobulin classes IgG, IgM, and IgA. Increased protective capacity of IgM and IgA over IgG1, on a weight basis, was demonstrated. The present study indicates that S agalactiae preparations, when introduced into the mammary gland, can give rise to local antibody synthesis in the vaccinated glands.
Animals↗
A review of laboratory methods for identification of group B streptococci (Streptococcus agalactiae).
A selected review is presented of the history of Group B streptococcal infections and the laboratory tests used to identify Group B streptococcus (Streptococcus agalactiae), an opportunistic pathogen which causes serious infections in newborn infants and compromised patients in other age groups. Its isolation may be increased by growth in a selective medium. The methods for Group B streptococci identification include the hydrolysis of sodium hippurate, the CAMP reaction, pigment production, and antibiotic disk susceptibility. Also, immunological tests, such as Lancefield's classical precipitin test, immunofluorescence staining, counterimmunoelectrophoresis, and coagglutination are available.
Bacteriological Techniques↗
R plasmids in Streptococcus agalactiae (group B).
Two plasmids determining resistance to tetracycline (RIP500) and to chloramphenicol, erythromycin, lincomycin, and pristinamycin I (RIP501) were isolated from a strain of Streptococcus agalactiae. The frequency-of-resistance loss is very low for RIP500 (<3 x 10(4)) but higher for RIP501 (the efficiency was dependent upon the curing agents and incubation temperature and varied between 0.5 and 96%). Derivatives susceptible to all drugs were also obtained. RIP500 and RIP501 have similar molecular weights (17.9 x 10(6) and 20 x 10(6), respectively) and represent different percentages of total deoxyribonucleic acid (0.4 and 4%, respectively). The number of copies of RIP500 and RIP501 per cell is different, and these plasmids are likely replicated under different kinds of control (stringent and/or relaxed). No plasmid deoxyribonucleic acid was found in a derivative of strain B96 susceptible to all drugs.
Centrifugation, Density Gradient↗
Diagnostic utilization of hemolytically active exosubstances of certain gram-positive bacteria. I. Detection of staphylococcal hemolysins with prepurified preparations of staphylococcal beta-toxin and CAMP-factor of Streptococcus agalactiae.
The authors have modified the one-plate method for the detection of staphylococcal hemolysins. They recommend to use in this method a prepurified form of staphylococcal beta-toxin and of streptococcal CAMP-factor instead of the exclusively beta-tonin-producing strain of Staphylococcus aureus and instead of the intensively CAMP-test positive Streptococcus agalactiae strain, respectively. The authors determined concurrently staphylococcal hemolysins, using a three-plate method in which alpha-antitoxin was employed, to ensure a better evidence of alpha-toxin. A total of 494 staphylococcal strains were examined by both methods. Of this number, 446 Staphylococcus aureus strains were of diverse host origin and 48 were coagulase-negative staphylococcal strains. On the basis of the various hemolytically active staphylococcal toxins, the authors recommend the suggested modification of the one-plate method for their routine detection.
Animals↗