THE TWORT-D'HÉRELLE PHENOMENON : II. LYSIS AND MICROBIC VARIATION.

1. When the few individuals still alive in a dissolved culture of Bacillus coli are transplanted on slanted agar, a culture results which possesses new characteristics. First observed by Bordet and Ciuca, this culture received the temporary name of modified coli. In the study described above, we found that this modified coli is very heterogeneous and that its three principal characteristics, resistance to lysis, lysogenic properties, and mucoid growth, are shared among different types of organisms that can be isolated when the normal original coli (coli O) is plated together with increasing quantities of the lytic agent: (a) a certain number of bacilli are just resistant enough to survive and grow in the presence of a moderate quantity of lytic agent, but they are still more or less sensitive and produce diseased, irregular, and lysogenic colonies; (b) a few of the organisms are able to resist concentrated lytic agent; they are entirely resistant and give round, healthy, and non-lysogenic colonies (coli O R 2); and (c) among these resistant bacilli only a very few are mucoid (coli 0 R 1). All these types are not motile and not fluorescent. 2. The original coli, when allowed to age, can be dissociated, as we have shown in a preceding paper (1), into two types of organisms, the non-motile coli S and the very motile coli R. Submitted to lysis, coli S gives a very small number, coli R a much greater number of resistant organisms (coli S R and coli R R), but both types never yield any mucoid growth. 3. An old culture of the modified coli obtained by Bordefand Ciuca, when streaked on agar plate, gives two types of colonies: a mucoid and fluorescent type (coli M 1) and a non-mucoid and translucent type (coli M 2). Both types are motile. Coli M 2, once isolated, keeps its individuality even after several passages in artificial media, but if again submitted to the lytic agent, a great number of mucoid bacilli are found among the organisms which are still alive. Consequently, different types of Bacillus coli differ greatly in their ability to give a mucoid growth when submitted to the lytic agent. Some, like coli S and coli R, do not possess this property at all. Others, like coli O, possess it to a certain extent, and some, like coli M 2, have it to a very high degree. 4. The mucoid and motile Bacillus coli M 1, when streaked every day on agar plates, remains indefinitely mucoid and motile, but occasionally a mucoid colony shows an indentation made up of non-mucoid growth, which, transplanted, gives a pure culture of non-mucoid and non-motile organisms, coli M 1 a. This new type possesses all the characteristics of the original strain of Bacillus coli, and therefore must be considered as a reversion. 5. The mucoid and motile Bacillus coli M 1, kept growing in synthetic medium, remains perfectly stable; on the other hand, when it is transplanted in broth, Bacillus coli M 1 turns very quickly into a non-mucoid but still very motile organism, or Bacillus coli M 1 b. This last type, which produces translucent colonies on agar and grows granular in broth, never reverts to the mucoid form, even in the presence of lytic agent. 6. A single strain of Bacillus coli has thus been made to yield eleven different forms, all distinguished by striking characteristics, but still possessing the specific properties of Bacillus coli. Nine of these forms have been submitted to antisera prepared with three different types (Bacillus coli O, Bacillus coli S, and Bacillus coli R). While seven out of these nine strains were agglutinated by any of the three antisera, only the original Bacillus coli (Bacillus coli O) and the reversion to the original type (Bacillus coli M 1 a) were not agglutinable, even by their corresponding antiserum; i.e., the serum obtained from a rabbit immunized with Bacillus coli O, which, however, agglutinated the other types

Studies on the d'Hérelle phenomenon

The inhibition produced by the lytic agent on the growth of Bacillus coli is greatly influenced by the reaction of the medium; it is faint in a slightly acid (pH 6.8) or neutral (pH 7) or even slightly alkaline broth (pH 7.4), but is much stronger in a more alkaline medium (pH 8 or 8.5). We have isolated from the original strain of Bacillus coli two types of organisms; one (Type S) is sensitive to the lytic agent, the other (Type R) is much more resistant. These types are distinguished also by other characteristics: Type S grows quickly in artificial medium and is non-motile; Type R grows more slowly, is extremely motile, much less phagocytable, and more virulent. Both types produce indole and ferment carbohydrates, with the exception of saccharose. Both types keep their individuality even after passage through a guinea pig. We have also demonstrated that even a culture of a single type, Type S for instance, is not a homogeneous whole but is made up of organisms of varying resistance to the lytic agent; only a few are resistant enough to overcome the strong action of the undiluted lytic agent. On the other hand, only a few as well are sufficiently sensitive to be dissolved even by very dilute lytic agent. This explains why dilute lytic agent spread on an agar plate seeded with Bacillus coli confines its action only to certain places and produces the small round areas of dissolution that d'Hérelle considered as "colonies of bacteriophage." Moreover, we have observed the same localized action even with non-dilute lytic agent when submitting to its action cultures of greater resistance. Our original lytic agent was found to be specific; it acted exclusively on the coli with which the guinea pigs were injected. By allowing this original lytic principle to act on broth cultures of our two types of Bacillus coli, we have obtained two new filtrates. The first, resulting from dissolution of the sensitive Strain S, is specific as is the original filtrate. But with the second, obtained from the resistant Strain R, Dr. Wollstein has found a marked action on Shiga, on Flexner, and on Hiss dysentery bacilli. In consequence of this observation, we have been able, by a method of successive passages through appropriate strains, to extend the lytic power to other species, as typhoid and paratyphoid bacilli, and have obtained by this somewhat different technique results similar to those recently published by Bordet and Ciuca

Preliminary report on a Staphylococcus bacteriophage

peer reviewe

Pluralité, hétérogénéité, autonomie antigénique des virus des plantes et des bactériophages

peer reviewe

Mise au point de quelques notions de bactériophagie

1. Le phénomène d'Hérelle est identique au phénomène décris précédemment par Twort. 2. Les extrêmes différences individuelles de sensibilité des colibacilles et des bacilles typhiques aux bactériophages, rendent illusoire le traitement des affections colibacillaires et typhiques par un stock-bactériophage. Chaque cas doit être traité spécifiquement. Par contre, l'existence pour la Staphylocoque d'un bactériophage dont le champ d'action s'étend pratiquement à toutes les souches de ce micorbe, permet de traiter les infections Staphylococciques par ce stock-bactériophage polyvalent, à condition que son activité n'ait pas été altérée au cours de la préparation ; Le bactériophage agit rapidement. Il fait apparaître des anticorps antilytiques ; son usage ne doit et ne peut donc être prolongé. Il faut consolider son action par l'usage des mycolysats

Le rôle du contact dans la coagulation du sans: Diminution de la teneur en sérozyme du sans consécutive à l'anémie du foie

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