A taxonomic study of the genus Haemophilus, with the proposal of a new species

The haemolytic activity of Haemophilus species

The importance of the species of blood employed for detection of haemolysis in seventy-seven Haemophilus strains of human and porcine origin was studied. Significant differences in the visibility of haemolytic zones obtained on the different blood agar media were observed. In decreasing order, the suitability of the species of blood was: calf, sheep, human, rabbit, poultry and horse blood. On plates containing washed sheep or calf red cells the haemolysin of all 36 strains of Haemophilus pleuropneumoniae acted synergistically with the beta-toxin of the Staphylococcus aureus strain used as "feeder strain", giving rise to a lytic phenomenon resembling the CAMP reaction.

Rapid diagnosis of Enterobacteriaceae. I. Detection of bacterial glycosidases

The paper describes a number of tests for the rapid detection of glycosidases including alpha-glucosidase, beta-glucosidase, beta-glucuronidase, beta-xylosidase and alpha-fucosidase. The methods use heavy suspensions of viable but non-multiplying bacteria in a buffered solution of a chromogenic substrate. The results of the tests are readable within 4 h. The application of these tests to a collection of 633 strains of Enterobacteriaceae and Vibrionaceae demonstrates that some of the tests may be valuable additions to the present tests available for the identification of bacteria belonging to these families. beta-glucuronidase activity was observed only in strains of the Escherichia-Shigella group. 97 per cent of the Escherichia strains possessed beta-glucuronidase activity. beta-xylosidase activity was almost completely restricted to strains of the Klebsiella-Enterobacter group in addition to Yersinia strains. None of the strains possessed alpha-fucosidase activity.

Initial colonization of teeth in monkeys as related to diet

The initial phases of plaque development on nonretentive tooth surfaces were studied bacteriologically in Macaca irus monkeys fed by stomach tube and provided with various oral supplements. Except for the oral implantation of Streptococcus mutans in some of the animals, the oral flora was not changed prior to the studies. Dental plaque was allowed to develop on initially cleaned tooth surfaces for 3 to 5 h. Plaque samples were collected and cultured on a number of selective and nonselective agar media, and several hundred isolates from each sample were isolated and identified. The numerically predominant organisms in initial plaque were S. mutans, Streptococcus sanguis, and Actinomyces viscosus. Additional organisms regularly found, but usually in smaller numbers, were Streptococcus mitior and a group of fastidious gram-negative rods including Haemophilus species, Eikenella corrodens, and Actinobacillus actinomycetem-comitans. The colonization of S. mutans was dependent on sucrose and occurred at the expense of S. sanguis. In these experiments S. mutans accounted for 25 to 65% of the primary plaque formers. All other species encountered colonized the teeth irrespective of the diet. It is postulated that the early sucrose-dependent establishment of S. mutans directly on the enamel pellicle plays a key role in the development of a cariogenic plaque.

Ampicllin sensitivity and biotypes of recent Danish isolates of Haemophilus influenzae

Among 148 strains of Haemophilus influenzae isolated in 1975 from different localities in Denmark, none was found to be resistant to ampicillin. A majority of the strains belonged to biotypes I, II and III and the presence of a partial correlation between biotype and origin was confirmed.

The taxonomy of haemophili isolated from conjunctivae

The paper provides a description of 112 Haemophilus strains isolated from cases of conjunctivitis in Egypt, Tunisia, Denmark, and the U.S.A., and aims at a clarification of the taxonomy of haemophili implicated in conjunctivitis. Although the study confirms the diversity of haemophili which can be isolated from inflamed conjunctivae, the vast majority of strains could be assigned to either biotype II or III of H. influenzae. Thirteen strains possessed all the characteristics of the Koch-Weeks bacillus. However, judged by the findings the recognition of the Koch-Weeks bacillus as a separate species does not seem tenable. It is suggested that this organism is considered a haemagglutinating variety of H. influenzae biotype III. The study indicates that the haemagglutinating ability per se, which can be found in strains of several taxa of Haemophilus, is associated with a special pathogenic potential.