Strains Of Streptococcus Milleri Research Articles

Purulent Pericarditis Caused by Streptococcus Milleri Strains; the Gained Experience from Nine Reported Cases

Bacterial pericarditis caused by Streptococcus Milleri Group (SMG) strains is a particularly exceptional pathology. All the eight previous reported cases were under the care of medical teams and the seven existed reports in medical journals were more or less from this perspective. Herein, we reported a unique case of a pericardial-cutaneous fistula resulting from a recurrent purulent pericardial effusion caused by SMG strains, which had been treated with open surgical drainage two months before. A thorough review of the surgical treatment options and the results has also been presented.

Bactericidal action of tachyplesin I against oral streptococci.

Tachyplesin I, a polycationic antimicrobial peptide isolated from hemocytes of horseshoe crabs, kills bacteria by disrupting the membrane potential of the cytoplasmic membrane. The present study shows that, among 36 oral streptococcal strains, 12 of 21 Streptococcus sanguis, 3 Streptococcus mutans, 9 Streptococcus salivarius and 3 Streptococcus milleri strains were susceptible to tachyplesin I, whereas 9 S. sanguis strains were resistant. Interestingly, these resistant strains include the clinical isolates from both Kawasaki disease and Behçet patients. According to the time-kill study, tachyplesin I inhibited irreversibly the growth of S. sanguis, S. mutans and S. salivarius strains within 20 min and an S. milleri strain within 80 min. Although it has been suggested that Escherichia coli cultured in rich media were more susceptible to tachyplesin I, the present results show that only 3 S. milleri strains were more sensitized to tachyplesin I in a glucose-supplemented medium, and other tested strains were not. Similarly, only 4 strains were more resistant to tachyplesin I in saline than these were in a rich medium.

Serological and biological characteristics of "Streptococcus milleri" isolates from systemic purulent infections.

Ninety-one Streptococcus milleri strains isolated from various systemic purulent lesions of 68 patients were examined by physiological and serological tests. Most strains formed a smooth colony (66 strains), did not form spontaneous aggregation of cells in BHI broth culture (79), were non-beta-haemolytic (alpha-35 or non-41), and belonged to biotype Ia (49) or Ib (34) and to API taxa S. milleri I (41) or II (38). Almost all of the beta-haemolytic strains as well as two-fifths of the non-beta-haemolytic belonged to API taxon I; strains of API taxa II and III were non-beta-haemolytic and non-haemolytic, respectively. Two-fifths (38) of the isolates belonged to one of eight serotypes, a-g and k, and more than half (47) to Lancefield groups A, C, F or G, the most frequent being type b (19) and group F (33). Fifteen strains carried simultaneously type a/group A, b/C, c/C, e/G, f/F or k/G antigens. Nineteen were neither typable nor groupable. All the 38 serotypable isolates were non-beta-haemolytic and not members of API taxon III, and were serologically and physiologically similar to oral S. milleri. The isolates from various infected sites--sputum, thorax, abdomen, urogenitalia, skin, eye and dental--exhibited distinct combinations of biological and serological properties. These results suggest that serotyping, haemolytic properties and API taxon, and their combinations, would be useful methods to trace oral S. milleri in systemic infections.

Lactose-sensitive and -insensitive cell surface interactions of oral Streptococcus milleri strains and actinomyces

Of 158 oral Streptococcus milleri strains, 46 exhibited cellular coaggregation with the reagent strains of the actinomyces coaggregation groups A, B, and/or E. All but 1 of the 33 serotype b, e, f/F, and k/G strains belonged to streptococcus coaggregation group 2, and only 14 strains of limited seroclasses (g, i, Lancefield group F, or untypeable) appeared to be members of group 5, 3, or 4 (10, 3, and 1 strain, respectively). Thus, S. milleri infrequently exhibits lactose-inhibitable coaggregation with actinomyces.

Estimation of growth parameters for some oral bacteria grown in continuous culture under glucose-limiting conditions

The coexistence of bacteria in natural environments can often be explained in terms of competition for a growth-limiting substrate(s), and the outcome of such competition depends upon relevant growth parameters such as substrate affinity and yield. Dental plaque bacteria are frequently carbon and energy limited. Growth parameters for seven oral Streptococcus species and one Actinomyces viscosus strain were estimated under glucose-limited conditions in continuous culture. In all strains, mixed-acid fermentation occurred at low growth rates, while amounts of lactate increased at higher growth rates. Two important growth parameters, mumax and Y glucose, were very similar in the two serotype c Streptococcus mutans strains (T8 and Ingbritt), one of the serotype d/g Streptococcus mutans strains (OMZ65), and the two Streptococcus milleri strains (699B3 and B448). Two other serotype d/g S. mutans strains (KIR and B13) were divergent from this group and had lower mumax values and a lower Y glucose. The maintenance energy coefficients were lower in the S. mutans serotype c strains, and the highest values were observed in the S. milleri strains. While A. viscosus had a lower mumax, its lower maintenance rate and significantly higher yield indicate that it deals much more efficiently with glucose than do the streptococci. The most striking feature of amino acid utilization was that arginine was completely consumed by S. milleri strains; similarly, A. viscosus used up all available asparagine as did one of the S. milleri strains at faster growth rates. It is suggested that the ability of strains of S. milleri and S. sanguis to utilize arginine in addition to carbohydrate as a source of energy may explain why such organisms increase in proportion in the plaque of subjects consuming diets almost devoid of fermentable carbohydrate.

Incidence and characterization of beta-hemolytic Streptococcus milleri and differentiation from S. pyogenes (group A), S. equisimilis (group C), and large-colony group G streptococci.

The biochemical characteristics of 172 clinical isolates of group A, C, F, or G or "nongroupable" beta-hemolytic streptococci were examined. Among these isolates, 91 were identified as beta-hemolytic strains of Streptococcus milleri. The remaining isolates included 20 Streptococcus pyogenes, 21 Streptococcus equisimilis, 37 large-colony group G streptococci, and 3 unidentified nongroupable isolates. A majority (84%) of the S. milleri strains possessed Lancefield group antigen (3 A, 27 C, 41 F, and 5 G), whereas 15 S. milleri strains (16%) were nongroupable. Serological tests did not differentiate S. milleri isolates with group A, C, or G antigen from S. pyogenes (group A), S. equisimilis (group C), or large-colony group G streptococci. Biochemical tests which were found useful for differentiation included the Voges-Proskauer test, hydrolysis of pyroglutamic acid and beta-D-glucuronide, bacitracin susceptibility, and acid production from ribose. S. milleri represented 56% of the group C, 100% of the group F, and 83% of the nongroupable beta-hemolytic streptococci isolated in our clinical laboratory, whereas the incidence of S. milleri among group A and group G streptococci was estimated to be low. The role of beta-hemolytic S. milleri as a cause of human infection remains obscured by the failure to routinely differentiate S. milleri from other beta-hemolytic streptococci.

Fatty acid composition of Streptococcus milleri.

The cellular fatty acids of 31 strains belonging to the Streptococcus milleri group were analysed by capillary gas-liquid chromatography. Results were compared with findings from biochemical differentiation of the strains into Streptococcus constellatus (two strains), Streptococcus anginosus (16 strains) and Streptococcus intermedius (13 strains). Eight strains of various other streptococci were included as internal references, including three strains of streptococcus morbillorum, three strains of beta-hemolytic streptococci, and two strains of enterococci. The Streptococcus milleri strains formed a very homogeneous group according to fatty acid composition and were easily differentiated from other groups. However, within the group, it was not possible to differentiate Streptococcus constellatus, Streptococcus anginosus and Streptococcus intermedius by fatty acid composition alone.

In-vivo dental plaque-forming ability and relative cariogenicity of the bacteria Streptococcus mitis and Streptococcus sanguis I and II in mono-infected gnotobiotic rats

Sixteen strains of Streptococcus mitis, Streptococcus sanguis I and Strep. sanguis II were tested for cariogenic potential and in-vivo plaque-forming ability in a gnotobiotic WAG/RIJ rat test system. All strains produced far less fissure plaque in vivo than strains of Streptococcus milleri or Streptococcus mutans. There was less extracellular matrix around cells of Strep. mitis or Strep. sanguis than around Strep. mutans, in the fissures. Dense sheets of cells were observed only with Strep. mutans. Some localized colonization of exposed smooth surfaces occurred with most strains. Strep, mitis produced no caries in three tests, low-caries scores in two tests and high-caries scores in one test. A single strain of Strep. mitis produced a highly-cariogenic variant able to ferment raffinose. Strep. sanguis I induced low-levels of caries in 12 tests; one test of NCTC 7865 produced moderate levels of caries, and another test of 311 produced no caries. Strep. sanguis 311 was dextran-negative. Strep. sanguis II strains induced no caries in three tests, low caries scores in six tests and moderate levels of caries with Strep. sanguis 402. No strain of Strep. mitis or Strep. sanguis was able to induce smooth-surface lesions.

Bacteriocin production by Streptococcus milleri.

Bacteriocinlike activity was sought among 58 streptococcal strains using a deferred antagonism technique and 50 indicator strains. Antagonist production was generally increased by glucose supplementation of brain heart infusion agar and reduced by addition of calcium carbonate. Activity due to complete bacteriophage was excluded, as was toxic buildup of lactate, acetate, or ethanol. Hydrogen peroxide activity was responsible for all, or part, of antagonist activity in Streptococcus mutans tested and in nine strains of S. milleri. Virtually all isolates of S. milleri tested were sensitive to the bacteriocinlike activity of S. mutans NCTC 10832.

Occurrence and cultural features of Streptococcus milleri in various body sites.

An investigation was made into the habitat of commensal strains of Streptococcus milleri. These showed distinctive patterns of cultural features, dependent on their sites of origin, which were compared with those prevalent in strains grown from the appendix, 'anal' lesions, and Bartholin's abscesses. A biotype, which showed a marked affinity for the vagina and produced acid from raffinose and melibiose, was identified.

The cultural and biochemical characters of Streptococcus milleri strains isolated from human sources.

A collection of 346 strains of Streptococcus milleri from a variety of human sources was examined culturally and biochemically, and for the presence of Lancefield group antigens. Most of the strains were non-haemolytic and ungroupable, but 25% were beta haemolytic and 19% were alpha haemolytic; 28% possessed a group antigen (A, 5%; C, 6%, F, 14%, G, 3%). These antigens were present in 69% of beta-haemolytic but in only 13% of alpha-haemolytic or non-haemolytic strains; beta haemolysis occurred in 82% of group-F strains, 43% of other groupable strains and 11% of ungroupable strains.The following reactions were given by > 80% of S. milleri strains: hydrolysis of arginine and aesculin, a positive Voges-Proskauer reaction, and acidification of trehalose, lactose, salicin and sucrose. A minority of strains showed enhancement of growth by CO(2), bile tolerance, NaCl tolerance, and ability to acidify other sugars, notably mannitol, raffinose and melibiose. Departures from the modal pattern of biochemical reactions showed a weak correlation with the type of haemolysis and the presence or absence of a group antigen but were not sufficiently systematic for clear-cut subdivisions to be recognized within the species.S. milleri therefore appeared to comprise a ;central' group of non-haemolytic strains that rarely formed a Lancefield-group antigen, in which the aesculin reaction was nearly always positive, lactose was usually acidified, and a considerable minority showed enhancement of growth by CO(2) and bile tolerance. Deviations from this pattern were of two main types. (1) ;Loss' of one or more of these reactions, which tended to be associated with beta-haemolysis and presence of a group antigen. In these respects, alpha-haemolytic strains tended to occupy an intermediate position. (2) ;Gain' of the ability to acidify additional sugars, notably raffinose and melibiose or mannitol; this occurred mainly among otherwise typical non-haemolytic strains that were rarely groupable.Only 12% of isolations from the bloodstream of patients suffering from systemic infections were beta haemolytic and only 18% possessed a group antigen, but a considerably greater proportion of those from visceral abscesses were beta haemolytic (28%). Among isolations from superficial lesions in some body sites there were considerably greater proportions of beta-haemolytic and groupable strains; thus, nearly one-half of those isolated from the abdomen other than the female genital tract were beta-haemolytic and over one-half were groupable. On the other hand, strains from the teeth and gums were nearly always non-haemolytic and ungroupable, and most vaginal isolations were of non-haemolytic strains with a wide sugar-fermentation pattern.