No abstract

A taxonomic study of Haemophilus vaginalis Gardner and Dukes was undertaken to determine relationships between this organism and members of other genera. The methods utilized included Adansonian analysis, deoxyribonucleic acid (DNA)-DNA hybridizations, electron microscopy, and biochemical analysis of cell envelopes. By numerical analysis, all 78 clinical isolates and reference strains examined were related to each other at a similarity level exceeding 95%. No subspecies or biovars were observed. DNA-DNA hybridizations showed no genetic relationship between H. vaginalis and members of the genera Haemophilus, Pasteurella, and Streptococcus. Also, no relationship was observed between H. vaginalis and CDC DF-1. In the absence of existing genera with genetic features compatible with H. vaginalis, we propose the new genus Gardnerella for inclusion of organisms presently designated as either H. vaginalis or Corynebacterium vaginale. Gardnerella is defined to include catalase-and oxidasenegative, gram-negative to gram-variable bacteria with laminated cell walls which produce acetic acid as the major end product of fermentation. The type species of Gardnerella is G. vaginalis (Gardner and Dukes) comb. nov. Due to the unusual cell wall of this organism, this new genus is not presently assignable to a family.

Features of 378 clinical isolates of saccharolytic, nonfermentative Gram-negative rods and 20 reference strains were examined. All but four of the clinical strains were assigned to recognized taxa, namely Acinetobacter, Chromobacterium, Flavobacterium, Pseudomonas aeruginosa, Pseudomonas fluorescens, Pseudomonas maltophilia, Pseudomonas multivorans, Pseudomonas putida, Pseudomonas stutzeri, and Xanthomonas.

One hundred and thirty-one strains of nonsaccharolytic and weakly saccharolytic Gram-negative rods recently isolated from clinical specimens were examined with a battery of 74 tests, mostly biochemical. All but five of these strains were thus assigned to established taxa. Alkalinization of amides and organic acids was a particularly useful feature for identifying these bacteria.

Lysis by KOH and hydrolysis of L-alanine-4-nitroanilide were compared with the Gram reaction of aerobic, microaerophilic, and anaerobic bacteria. Both tests correlated well with the Gram reaction with nonfermentative bacilli and Bacillus species, whereas they did not correlate with nonsporulating anaerobes. Only campylobacteria were KOH positive and L-alanine-4-nitroanilide and gram negative.

Brucellae are known to be facultative intracelluiar parasites (1, 2). Braude (2) showed that within 24 hours after infection of guinea pigs with Brucdla abortus, nearly all brucellae detectable in the peripheral blood were within neutrophiles. These infected phagocytes (and extracellular bacteria) were removed from the circulation by the spleen, liver, and other organs. Focal aggregations of parasitized polymorphonuclear and mononuclear phagocytes in these organs led to development of granulomas. Phagocytized brucellae were not destroyed but rather appeared to multiply intracellularly until many phagocytes were completely engorged. With onset of the mature granuloma, marked by the appearance of epithelioid cells, microscopically evident brucellae gradually disappeared from the tissues.Intracellular multiplication of Brucella in vitro has recently been demonstrated (3, 4). Similar methods (5-7), and methods involving passive transfer of cells or humoral factors (8, 9), have been applied to the study of acquired immunity in tuberculosis, but with equivocal results. Acquired resistance in brucellosis is much more amenable to investigation because high titer agglutinating antibody can be produced, and because reproducible viability counts from infected cells and tissues are possible.The studies reported here were initiated to determine the reasons for the restricted multiplication of brucellae within phagocytes of animals previously infected with Brucella. While this work was in progress, others (4, 10) reported that monocytes from vaccinated guinea pigs and rabbits restricted intracellular growth of brucellae in a cell culture system, whereas marked multiplication occurred within normal monocytes under the same conditions. Our findings confirm and extend their results. Materials and MethodsAnimals.--Three species were used: male guinea pigs (350 to 500 gm.), female rats of the Sprague-Dawley strain (250 gin.), and young adult (about 20 gin.) mice of both sexes (inbred progeny of LAFa strain of mice).

Stream and lake water from the Mammoth Lakes region of California was sampled for Yersinia enterocolitica. From 10 of the 34 sites examined, organisms were isolated that were biochemically identified as Y. enterocolitica. Only one of the ten strains could be serologically confirmed. This strain was identified as Y. enterocolitica serotype 16. Although an outbreak of enteritis in the area prompted this study, no correlation with gastrointestinal disease could be established since the majority of the strains were untypeable.

SUMMARYThe bacteriophages of Listeria monocytogenes have been studied with respect to isolation techniques and their use as diagnostic tools and as aids in epidemiological investigations. The occurrence of lysogeny was investigated in 123 strains isolated from human and animal sources throughout the world. Conventional procedures for isolation of phage were unreliable with Listeria since lysogenic strains did not always, by spontaneous lysis, release a detectable amount of phage. However, after exposure to ultraviolet radiation, such strains were induced to produce up to lo7 plaque-forming particles/ml. Some strains which did not release phage produced substances after irradiation possibly analogous to colicines. The lytic spectrum of 11 phages against 149 strains of Listeria was studied and a system of classification, with five of these phages, was used to place 127 of these strains in 8 phage types. Nearly all of the untypable strains were rough, undergoing dissociation, or were lysogenic. Phage susceptibility appeared to be closely associated with the serological type of the strain, but showed no relation to the animal source or the geographical origin. These studies indicated that Listeria phages could be used as a means of generic identification and also as a substitute for or an adjunct to serological typing in epidemiological investigations.