RELATIONSHIPS OF THE ENCAPSULATED BACILLI WITH SPECIAL REFERENCE TO BACT. AEROGENES

THE DISTRIBUTION OF FRIEDLANDER'S BACILLI OF DIFFERENT TYPES

In a study of the distribution of the specific types of Friedländer's bacillus, it is shown that: (1) Of 80 strains 52 per cent belong to Type A, 15 per cent to Type B, 9 per cent to Type C, and 24 per cent to Group X. (2) Type A contains for the most part strains derived from diseases of man and more than 70 per cent are associated with pneumonia in man. (3) Type B includes the greatest number of strains from animal sources, while the heterogeneous strains comprising Group X come from the greatest variety of diseases. It was demonstrated that in a patient suffering with pneumonia due to Friedländer's bacillus (Type A), a specific precipitin reaction of the urine occurred in the corresponding (Type A) immune serum. A study of the sugar fermentation reactions of Friedländer's bacillus shows that (1) there is no correlation between serological type and fermentative activity; (2) the fermentation reactions are variable and therefore not reliable for distinguishing Friedländer's bacillus from closely allied organisms; (3) the strains of Group X show the greatest variation in fermentation, and (4) of 15 strains unable to ferment lactose, 13 belong to Type A.

Biochemical classification of Klebsiella correlated with the severity of the associated disease

The biochemical classification of the Klebsiella proposed by Cowan, Steel, Shaw, and Duguid (1960) has been applied to 50 strains isolated as the pure or predominant growth from sputum, and Klebsiella species have been correlated with the severity of the chest infection in the patient. A modification in nomenclature is suggested.

Fermentation of polysaccharides by Klebsielleae and other facultative bacilli

Fermentations of 10 polysaccharides by species of the family Enterobacteriaceae were examined. Algin, guar, karaya, xanthan, and xylan were not fermented by any of the strains tested. Most of the activity was found in the tribe Klebsielleae. Klebsiella oxytoca fermented amylopectin (97% of the strains studied), carrageenan (100%), inulin (68%), polypectate (100%), and tragacanth (100%). Klebsiella pneumoniae fermented amylopectin (91%), carrageenan (100%), and tragacanth (86%). Carrageenan was also fermented by Enterobacter aerogenes (100%), Enterobacter agglomerans (63%), Enterobacter cloacae (95%), and Pectobacterium (38%). Pectobacterium shared polypectate fermentation (100%) with K. oxytoca. With one exception, Serratia strains were negative on all polysaccharides. These results, along with other evidence, indicate that (i) the genus Klebsiella is biochemically the most versatile genus of the tribe, (ii) because of its distinct characteristics, K. oxytoca warrants species designation separate from K. pneumoniae, and (iii) some food additives generally considered indigestible can be metabolized by a few species of facultative bacilli, whereas others appear to be resistant.

Potential pathogens in the environment: Klebsiella pneumoniae, a taxonomic and ecological enigma

A nitrogen-deficient medium and m-Endo agar were employed in the isolation of members of the tribe Klebsielleae from surfaces of vegetables and seeds. With m-Endo agar at an incubation temperature of 37 C, nearly 50% of the vegetables and seven out of seven seed samples yielded organisms which biochemically and serologically were identified as Klebsiella pneumoniae, Viable counts were generally in the range of 10(3) cells per g of vegetable peel or seed. Organisms classified as K. pneumoniae exhibited seven different IMViC patterns, with the --++, ++++, and -+++ patterns most common. Seven of the eleven K. pneumoniae serotypes encountered have previously been isolated from human urinary tract and other infections. Fifty percent of the 40 K. pneumoniae examined exhibited positive acetylene-reducing activity, i.e., they possessed the capability for fixing N(2). Vegetables containing K. pneumoniae may constitute a potential reservoir for human nosocomial genitourinary or other infections.

Klebsiella biotypes among coliforms isolated from forest environments and farm produce

Samples of water, soil, needles, and bark were collected from three different forest environments and from a pulp and paper mill. In addition, samples of fresh produce were obtained from a local supermarket. All samples were examined for total and fecal coliforms. The counts obtained from the forestrelated samples did not correlate with sample type or location. When 123 isolates were identified biochemically, 71% were Klebsiella, 19% Enterobacter, 8% Citrobacter, and 2% Escherichia. All the Citrobacter, 75% of the Enterobacter, and 65% of the Klebsiella were negative for growth in elevated coliform (EC) broth. All the Escherichia were EC positive. The counts obtained from the fresh produce were generally higher than the forest counts, but the distribution of biotypes was similar. Of the 146 isolates examined 64% were Klebsiella, 14% were Escherichia, 14% were Enterobacter, and 8% were Citrobacter. All the Enterobacter and Citrobacter were EC negative, whereas 25% of the Klebesiella and 80% of the Escherichia were EC positive.