Filter-passing bacteria in the nasal passages of animals.

Anaerobic cultures of the filtered nasopharyngeal secretions from man reveal a varied bacterial flora. There have thus far been described, Bacterium pneumosintes, 1 obtained from fresh cases of typical epidemic influenza, and three distinct groups 2 of Gram-negative, filterable, anaerobes, derived from patients with influenza, obscure upper respiratory affections, or common colds, as well as from persons supposedly healthy. To the latter three groups may be added another related species which will be described later and which has been isolated from a number of cases of infectious common cold.

The object of the present study was to determine whether, and to what extent, this class of microorganisms is distributed among laboratory animals. Accordingly, the filtered materials obtained from the nasal mucosa of 10 monkeys, 7 horses, 17 dogs, 5 cats, 20 rabbits, 20 guinea pigs, and 20 rats were cultured by the same methods which had yielded growth of the different species of bacteria from human secretions.

Suspensions in one per cent dextrose Ringer's solution were prepared of the nasal mucosa, dissected or curetted away from the underlying bone of recently killed animals, or of the nasal secretions collected on cotton swabs of living ones. The suspensions were filtered through Berkefeld “V” candles, impervious to Pfeiffer's bacilli or Bacillus prodigiosus, at 650 mm. Hg negative pressure. The culture media 2 used were the Smith-Noguchi fluid medium and rabbit blood agar plates, and the cultures were incubated for 7 days under anaerobic conditions in Brown's jara modification of the McIntosh and Fildes apparatus.

In no instance, thus far, have any filter-passing microorganisms been cultivated from this material by the methods employed. 3