On the Paratyphoid Group of Bacilli

Abstract

1. The term “paratyphoid group of bacilli” has been confined in the present enquiry to those strains which in their cultural characters and agglutination reactions are indistinguishable from B. suipestifer and B. paratyphosus (B). B. enteritidis Gaertner and B. paratyphosus (A) are excluded.2. The strains of bacilli belonging to the “paratyphoid” group can be separated into two classes by means of the absorption method, namely one group identical with recognised, standard strains of B. suipestifer and one identical with standard strains of B. paratyphosus (B); and we regard these two bacilli as separate organisms.3. In our experience, B. suipestifer has been found only in food or in outbreaks of acute illness attributable to food-poisoning, whereas B. paratyphosus (B) has been found in cases of paratyphoid fever or in persistent paratyphoid “carriers.”.4. We are disposed to put forward the suggestion indicated by these observations, that these two organisms have a different distribution in nature, the normal habitat of B. suipestifer being the alimentary canal of the pig (and other animals) and of food derived from such animals, whereas the normal habitat of B. paratyphosus (B) is the human alimentary tract (including the gall-bladder).5. The examination of cultures from the faeces and urine of 300 typhoid convalescents was completely negative, neither B. suipestifer nor B. paratyphosus (B) being obtained. These observations confirm those of other writers, and, apart from carrier cases, the occurrence of B. paratyphosus (B) in healthy human beings appears to be unknown in this country.Our thanks are due to Drs Fisher, Trautmann, Uhlenhuth, Williams, Rommeler, Prigge, Schern, Friedrichs, Savage and Fowler, who have very kindly supplied us with strains of bacilli for investigation.

The Interrelationships between the various members of theB. enteritidis—B. paratyphosusB Group of Bacteria

“…When specific sera are prepared against individual strains of this group, there appears to be a correlation between the degree of agglutination and hostorigin. It is probable that B. aertrycke belongs to this subgroup, and also those B. suipestifer strains of German origin which were studied by Bainbridge and O'Brien (1911). The bacilli isolated from mice dying during our own experiments, and hitherto referred to as B. suipestifer, have all the characteristics of this subgroup and should be placed in it.…”

“…The excellent survey of Uhlenhuth and Hiibener (1913) gives a summar y of the evidence acquired prior to that date, and considers it from the poin t of view of those who would divide the group into two subgroup s only , one confined to lfr-2 B. enteritidis (Gaertner),and the other including B. paratyphosus B, B.aertrycke, B. typhi-murium, B. suipestifer, and a host of allied organisms recovered from the tissues and excreta of sick or healthy animals. Bainbridge (1912) and Bainbridge and O'Brien (1911) have insisted on the distinction which may be drawn between B. paratyphosus B, on the one hand, and B. aertrycke and B. suipestifer on the other, by means of absorption tests. The identity which they found between the two latter types is probably invalidated, as pointed out by Tenbroeck (1920 a), by the fact that their B. suipestifer strains were of German origin, and may well have been of the type which would be referred to by recent American observers as swinetyphus bacilli.…”