Differentiation of Certain Genera of Gram Negative Bacteria 513 



any degree of certainty. The organism named AcJiromohacter 

 liquefaciens in the Collection of the Microbiology Department, 

 Brno, Czechoslovakia, in our hands appears to be a typical "para- 

 colon" rather than AcJiromohacter sp. and the Achromobacter 

 liquefaciens of Youatt (59) (48) has only very recently been 

 made available to us. A motile peritrichous flagellated Gram nega- 

 tive rod, originally named Achromobacter histaminiwn ( 33 ) was 

 found to be feniientative in its action on glucose, producing acid 

 and gas, and has in fact recently been assigned to the genus 

 Proteus (34). In Table 2 it will be noted that the AcJiromohacter 

 sp. are all recorded as being non-motile and non-pigmented. 

 This is because in our experience over a number of years we have 

 not so far encountered an organism from the marine environment 

 which is peritrichous and yet possesses the typical morphology 

 given in tlie original description by Frankland and Frankland 

 (17). Buftiaux and Gagnon (10) have also recently concluded 

 that members of the genus AcJiromohacter are non motile, since 

 they never once encountered a peritrichous organism correspond- 

 ing to AcJiromohacter Jiquefaciens, despite the fact that they 

 were working with organisms isolated from very widely differing 

 environments. Moreover, Thornley (57) working witli 390 bac- 

 teria isolated from chicken carcasses, found only two peritrichous 

 flagellated Gram negative rods among the 190 cultures which she 

 designated as AcJiromohacter sp. - and even these she hesitated 

 to designate to this group. All our species which have been as- 

 signed to the genus AcJiromoJmcter are non motile, non pigment- 

 ed, short, stout or coccoid rods occurring singly, in pairs, like 

 diplococci, or in short chains, forming a grey, ofi^ white slightly 

 opaque colony on agar, sensitive to penicillin and usually bio- 

 chemically inactive, i.e., having the so called "negative character- 

 istics" of the literature. In Hugh and Leifson's medium most 

 strains produce an alkaline reaction, some no reaction, and a few 

 strains are oxidative. In general, these organisms correspond to 

 the AcinetoJmcter genus jiroposed by Brisou and Prevot (8). It 

 is becoming increasingly clear to many workers that the species 

 described under the general Moraxella, Diplococci and even 

 Neisseria could all be grouped under the genus AcJiromoJmcter. 

 The AcJiromohacter sp. are distinguished from the Pseudomonas 



