BACTERIUM PATHOGENIC FOR WARM-BLOODED AND COLD-BLOODED ANIMALS 



189 



occurred within 24 hours after inoculation, and in 

 less than 41 hours eight of the rainbow and all 

 the brook trout were dead. All controls of these 

 two species lived. Results of the brown-trout 

 inoculations were not ?s striking as those of the 

 other two species. In 48 hours sLx of the brown 

 trout had died, but three of the contiol fish also 

 were dead. There were no further deaths in 

 either group. 



Gross pathological changes were observed in 

 inoculated yearling trout of the three species. 

 Inoculations were performed, as previously indi- 

 cated, using strain 1. Dead and living fish were 

 examined. Macroscopically, the artificially in- 

 fected trout did not show any external lesions 

 other than slight swelling and congestion in the 

 anal region. The most important and character- 

 istic internal pathological changes noted were as 

 follows: Intestine filled with a yellow or white 

 gelatinous mucus, particularlj' in the posterior 

 portion; blood vessels congested and intestinal 

 wall swoUen; liver redder in color than in the 

 controls, and spleen enlarged and much darker. 

 There was some exudate in the peritoneal cavity 

 and occasiozially the peritoneum in the posterior 

 portion of the abdominal cavity was congested. 



DISCUSSION 



Biochemically, the organisms described in this 

 paper are very similar to Paracolobactrum aero- 

 genoides; but the possession of a single polar 

 flagellum would place the bacteria in the genus 

 Pseudomonas. It is interesting to note that cul- 

 tures 1 and 2 differed from classical description 

 of members of the Paracolobactrum group in that 

 they formed indole and acetylmethylcarbinol. 

 The production of both substances is not a com- 

 mon occurrence within this genus. Though the 

 slow fermentation of lactose, its pathogenicity, 

 and presence of some Salmonella somatic antigens 

 suggests relationship to paracolons, the possession 

 of a single polar flagellum would, according to 

 the present taxonomic concepts, relate these or- 

 ganisms to the genus Pseudomonas. 



Paracolon types have been described in warm- 

 blooded and cold-blooded animals. Edwards, 



Cherry, and Bruner (1943) reported isolating a 

 paracolon type from the liver of a rattlesnake. 

 Hinshaw and McNeil (1946a) reported the isolation 

 of paracolon types that caused heavy mortality in 

 turkey poults. The same authors (1946b) isolated 

 related paracolon types from the livers of rattle- 

 snakes, suggesting a relationship between the 

 types isolated from snakes and those causing in- 

 fection in turkeys. Hinshaw and McNeil (1947) 

 reported the isolation of two sucrose-fermenting 

 paracolon types possessing antigenic components 

 of the Salmonella group from Pacific fence lizards 

 and of paracolons from gopher snakes and sick 

 turkey poults. 



Members of the genus Pseudomonas have been 

 isolated repeatedly in outbreaks of disease of 

 fishes and other cold-blooded animals (Schaeper- 

 claus 1941, Guthrie 1942). The relative fre- 

 quency of isolations of these groups of bacteria 

 from other cold-blooded animals, and the isola- 

 tions described in this paper, call attention to 

 the possibility that fish ma}- be carriers of these 

 microorganisms. It is also possible that the con- 

 verse is true, that fish acquire infection from organ- 

 ismscarried byhigheranimals. The fact that these 

 organisms have been shown experimentally to be 

 pathogenic for both cold-blooded and warm- 

 blooded animals places them in a unique position 

 and leads one to speculate on the role played by 

 fish with respect to infection in man. 



SUMMARY 



The isolation and description of a unique 

 bacterium pathogenic for warm-blooded and cold- 

 blooded animals is discussed. 



The ntiicroorganism described in this report has 

 a peculiar taxonomic position in that its single 

 polar flagellum is a characteristic of the genus 

 Pseudomonas, whereas relationship to the para- 

 colons is suggested biochemicaUy by its phj^sical 

 and antigenic properties. Paracolon organisms 

 producing acetymethylcarbinol and classified as 

 Paracolobactrum aerogenoides have been isolated 

 from the gastrointestinal tract of man diu'ing 

 epidemics, but this is believed to be the first 

 description of an organism similar to P. aerogen- 

 aides pathogenic for fish. 



