Distribution of beta haemolytic streptococci in pharyngitis specimens obtained from children

One hundred and nine isolates of beta haemolytic streptococci were recovered from 840 (13%) pharyngeal cultures obtained from children with acute pharyngitis. Seventy-four percent of these were group A, 4% were group B, 9% were group C, 1% were group D, 4.5% were group F, and 5.5% were group G. The significance of non-group A isolates in pharyngitis could not be evaluated in the absence of viral and serological studies. However, these findings demonstrate the predominance of group A beta haemolytic streptococci in acute pharyngitis in children, as compared to findings in adults.     

Arginine metabolism in lactic streptococci.

Streptococcus lactis metabolizes arginine via the arginine deiminase pathway producing ornithine, ammonia, carbon dioxide, and ATP. In the four strains of S. lactis examined, the specific activities of arginine deiminase and ornithine transcarbamylase were 5- to 10-fold higher in galactose-grown cells compared with glucose- or lactose-grown cells. The addition of arginine increased the specific activities of these two enzymes with all growth sugars. The specific activity of the third enzyme involved in arginine metabolism (carbamate kinase) was not altered by the composition of the growth medium. In continuous cultures arginine deiminase was not induced, and arginine was not metabolized, until glucose limitation occurred. In batch cultures the metabolism of glucose and arginine was sequential, whereas galactose and arginine were metabolized concurrently, and the energy derived from arginine metabolism was efficiently coupled to growth. No arginine deiminase activity was detected in the nine Streptococcus cremoris strains examined, thus accounting for their inability to metabolize arginine. All nine strains of S. cremoris had specific activities of carbamate kinase similar to those found in S. lactis, but only five S. cremoris strains had ornithine transcarbamylase activity.     

Autolysis in strains of viridans streptococci.

Seven strains of viridans streptococci of the species Streptococcus sanguis, S. mutans and S. mitis were investigated for autolysis. The effect of pH, salt concentration and temperature on the autolytic process was studied in Na2HPO4/NaH2PO4 buffer. Whole cells and walls of all strains autolysed most rapidly at pH values above 7. Autolysis of whole cells of S. sanguis and one strain of S. mitis (ATCC15909) was maximal in 0-05 TO 0-2 M buffer, while the two S. mutans strains and S. mitis ATCC15912 showed maximal autolysis in 0-5 and 1-0 M buffers. Cultures harvested in the stationary phase of growth possessed only slightly decreased autolytic activity compared with those from the exponential phase. Whole cells autolysed more rapidly at 37 degrees C Than at 45 degrees C and 10 degrees C. Autolysis of isolated walls of three strains of S. mitis (ATCC903, ATCC15909 and ATCC15912) was maximal at pH 7-0 AND 7-5 and in 1-0 M buffers. Streptococcus mitis ATCC15909 also showed maximal lysis in 0-01 M and 0-5 M buffers. An endopeptidase action of the autolytic system of S. mitis ATCC15912 was indicated by the progressive release of soluble amino groups during autolysis of the walls. No release of reducing groups was observed. Several free amino acids were released during autolysis of these walls, alanine, lysine and glutamic acid being in greatest quanitity.     

Distribution of superoxide dismutases, oxidases, and NADH peroxidase in various streptococci

Abstract Managanese-containing superoxide dismutase and NADH oxidase could be detected in all of the 23 strains belonging to different species or serotypes of the genus Streptococcus . NADH peroxidase activity was found in 7 strains. Pyruvate oxidase activity was only detectable in Streptococcus faecalis .     

Role of anaerobic streptococci in human pathology. Report I. Etiological significance of anaerobic streptococci in chronic tonsillitis]

The authors describe a method of isolation of anaerobic streptococci from the blood. A high seeding efficiency of anaerobic streptococci from the depth of the tonsils (75.1%) and from their surface (59.7%) and also from the blood (36%) pointed to the leading role of these microbes in the etiopathogenesis of chronic tonsillitis. In healthy individuals anaerobic streptococci are revealed (by culture method) on the surface of the tonsils but rarely (6%). Str. micros are the most incident in chronic tonsillitis (in 85.3% of cases-from the depth of the tonsils and in 77.5%-from the surface), whereas Str. anaerobius and Str. intermedius occur in individual cases only (8.4-7.5% and 6.3-15%, respectively). Pure culture of Str. micros was found in 36% of cases. Pathogenetic scheme of development of bacteriemia in chronic tonsillitis and rheumatism is presented. The isolated cultures were found to be resistant to the widely-used antibiotics.     

Distribution and serological specificity of sialidase produced by various groups of streptococci

The occurrence of a streptococcal sialidase (designated St-sialidase) in culture fluids of various streptococci was investigated. St-sialidase was found to occur in strains belonging to groups A, B, C, E, G, H, and L, and the unclassified strains, Streptococcus sanguis and Streptococcus uberis. St-sialidase of group A was confined predominantly to types 4 and 22. St-sialidases, extracted from the culture fluids of some selected strains, were antigenic, eliciting the formation of antibody which effectively neutralized the enzymatic activity of the enzyme. Antisera to the St-sialidases of groups A, B, C, E, G, and L, and Streptococcus sanguis were produced in rabbits. The St-sialidases of groups A, B, and E streptococci were serologically distinct and group-specific. The St-sialidases from groups C, G, and L were serologically homologous, but distinct from St-sialidases of the other groups. Antiserum to the enzyme of strain 10557 (S. sanguis) cross-reacted with the St-sialidase of strain 9927 (S. uberis).     

Survey of antimicrobial resistance in lactic streptococci.

A total of 26 strains of Streptococcus cremoris and 12 strains of Streptococcus lactis were challenged with 18 antimicrobial agents and with nisin in the Bauer-Kirby disk susceptibility test. All strains were susceptible to ampicillin, bacitracin, cephalothin, chloramphenicol, chlortetracycline, erythromycin, penicillin G, tetracycline, and vancomycin. All strains were resistant to trimethoprim, and almost all strains were resistant to sulfathiazole. Variability in resistance to gentamicin, kanamycin, lincomycin, nafcillin, neomycin, nisin, rifampin, and streptomycin was observed. MICs of these substances for the less susceptible strains were determined, and high-level resistance factors could not be detected, except in the case of nisin. S. lactis ATCC 7962 was resistant to at least 40-fold-higher concentrations of nisin (greater than 64 micrograms/ml) than most other strains tested. This strain was a potent nisin producer.     

Fractal fluctuations in human respiration.

The present study was designed to characterize respiratory fluctuations in awake, healthy adult humans under resting conditions. For this purpose, we recorded respiratory movements with a strain-gauge pneumograph in 20 subjects. We then used Allan factor, Fano factor, and dispersional analysis to test whether the fluctuations in the number of breaths, respiratory period, and breath amplitude were fractal (i.e., time-scale-invariant) or random in occurrence. Specifically, we measured the slopes of the power laws in the Allan factor, Fano factor, and dispersional analysis curves for original time series and compared these with the slopes of the curves for surrogates (randomized data sets). In addition, the Hurst exponent was calculated from the slope of the power law in the Allan factor curve to determine whether the long-range correlations among the fluctuations in breath number were positively or negatively correlated. The results can be summarized as follows. Fluctuations in all three parameters were fractal in nine subjects. There were four subjects in whom only the fluctuations in number of breaths and breath amplitude were fractal, three subjects in whom only the fluctuations in number of breaths were fractal, and two subjects in whom only fluctuations in breath number and respiratory period were fractal. Time-scale-invariant behavior was absent in the two remaining subjects. The results indicate that, in most cases, apparently random fluctuations in respiratory pattern are, in fact, correlated over more than one time scale. Moreover, the data suggest that fractal fluctuations in breath number, respiratory period, and breath amplitude are controlled by separate processes.     

Shedding of hyaluronate synthase from streptococci.

Hyaluronate synthase was shed into the culture medium from growing streptococci (group C) together with nascent hyaluronate. The mechanism of solubilization was analysed using isolated protoplast membranes. Solubilization increased when membranes were suspended in larger volumes, but it was temperature-independent and was not inhibited by protease inhibitors. Increased hyaluronate chain length enhanced solubilization. The soluble synthase could re-integrate into Streptococcal membranes in a saturable manner. The soluble synthase behaved like an integral membrane protein, although it was not integrated into phospholipid vesicles. In sucrose velocity centrifugation the synthase had a higher sedimentation rate in detergent-free solution, indicating that it existed in an aggregated state.     

Nosocomial transmission of group B streptococci.

The acquisition of group B streptococci by babies in a special-care baby unit and two postnatal wards was investigated over a six-month period using serology and phage typing. Sixty-three culture-positive babies were identified in the postnatal wards, one-third of whom had been born to mothers who were not carrying the organism in the genital tract or anorectal area during labour. A non-maternal source was identified for 14 of these 21 infants: either colonised mothers and babies in the same ward or, on one occasion, a member of the hospital staff. In the special-care baby unit, however, only one instance of nosocomial acquisition of group B streptococci was recorded despite a high prevalence of colonisation in the staff on the unit and the presence of heavily colonised babies. The results of this survey suggest that although sepsis caused by group B streptococci may be the result of nosocomial transmission, this may be prevented by careful attention to hygiene.