THE FERMENTATION OF PROPYLENE GLYCOL BY

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1 THE FERMENTATION OF PROPYLENE GLYCOL BY MEMBERS OF THE ESCHERICHIA-AEROBACTER- INTERMEDIATE GROUPS K. PIERRE DOZOIS, GREGORY A. LEE, C. JELLEFF CARR, FRANK HACHTEL AND JOHN C. KRANTZ, JR. Departments of Bacteriology and Pharmacology, School of Medicine, University of Maryland and Bureau of Laboratories of the Baltimore City Health Department Received for publication January 14, 1937 The possibility has been suggested of differentiating the "intermediates" from Escherichia and Aerobacter by the use of propylene glycol (Dozois et al., 1936). It was observed, in the limited number of cultures'studied, that Escherichia and Aerobacter formed acid from propylene glycol, while the "intermediates" did not. In order to determine whether the utilization of this glycol might serve as a convenient additional taxonomic characteristic of this group, extensive observations were deemed advisable. Therefore, the propylene-glycol broth medium was used, in the study of a number of stock cultures, and in the routine examination of strains isolated from water, milk, crabmeat, oysters and feces. In an attempt to differentiate between the various strains of the "intermediates" observations on the fermentation of propylene glycol, ethylene glycol, adonitol and inositol were made. Those coli-form microorganisms which were found to be methylred positive and Voges-Proskauer negative, and which also grew in citrate broth (Koser's) were classed as members of the "intermediate" group. METHODS AND MATERIALS One per cent of the specific sugar alcohol was added to sugarfree broth of a ph of 7.0. The indicator used was chlorphenol 9

2 10 DOZOIS, LEE, CARR, HACHTEL AND KRANTZ, JR. red. The broth was sterilized at 15 pounds for 15 minutes, excessive heating being avoided. The cultures were incubated for ten days and observed daily for acid and gas. In most instances 48 hours' incubation was sufficient for fermentation to take place. RESULTS Of the 33 cultures of the "intermediates" obtained from various stock collections, 16 failed to form acid from either propylene glycol or ethylene glycol, and 4 failed to form acid from propylene glycol but did produce acid from ethylene glycol. Of the 16 cultures giving negative results with both of the glycols, 5 produced acid and gas from adonitol and inositol. Of the 13 strains that formed acid from propylene glycol, 7 also produced acid from ethylene glycol, while all failed to affect adonitol and inositol (table 1, A). Forty-five cultures of "intermediates" were isolated from oysters, crabmeat and feces (see table 1, B). Of these, 21 were found to be both propylene-glycol and ethylene-glycol negative. Three that were negative with propylene glycol produced acid from ethylene glycol. Five of the group of 21 organisms fermented adonitol and inositol while all of the propylene-glycol negative, ethylene-glycol positive strains attacked adonitol and inositol. The other members of this group produced acid from propylene glycol; of these, 11 also formed acid from ethylene glycol. Only 1 of the organisms positive in both of the glycol broths fermented adonitol and inositol while 3 of the propyleneglycol positive and ethylene-glycol negative strains have this ability. Of the "intermediates" isolated from milk and water at the Baltimore City Health Department (table 1, C) 9 failed to form acid from propylene and ethylene glycol. Thirty-three produced acid from propylene glycol, of which 21 also formed acid from ethylene glycol. Approximately 44 per cent of the "intermediates" studied failed to form acid from propylene glycol. Of those that failed to utilize the propylene glycol about 13 per cent formed acid I T. F. Dozois, Maryland State Department of Health.

3 FERMENTATION OF PROPYLENE GLYCOL from ethylene glycol. Thirty-two and a half per cent of the "intermediates" produced acid from propylene and ethylene glycol while 23.3 per cent produced it only from propylene glycol. About 11 per cent of the "intermediates" fermented adonitol and inositol. All of those that fermented adonitol also fermented inositol TABLE 1 Observations on the reactions of Escherichia coli and the "intermediates" TOTA NUBER PROPYLENE ETHYLENE ADONITOL INOSITOL CTAZ NDL OF CULTURES GLYCOL GLYCOL GROWTH POSITIVE ACID "D A" ACID ACID GAS GMS A. "Intermediates" from various stock collections B. "Intermediates" from oysters, crabmeat and feces C. "Intermediates" from milk and water D. Escherichia coli Fecal17 - l Non fecal It is apparent from these observations that there are at least four distinct strains of the "intermediates" in so far as the glycol fermentations would indicate. It will be necessary for more detailed studies to make this classification complete. Thirty-four strains of Escherichia coli (table 1, D), 17 from feces and 17 from other sources, were obtained. Only one produced 11

4 12 DOZOIS, LEE, CARR, HACHTEL AND KRANTZ, JR. acid from propylene glycol. From the studies on these cultures of Escherichia coli it would seem that a close correlation exists between the failure to utilize citrate and the failure to produce acid from propylene glycol. While the indol reaction for members of the Escherichia and "intermediates" group is somewhat variable it would seem that a relationship between indol formation and propylene-glycol utilization by Escherichia coli may exist. The production of indol in most cases signifies an inability to ferment the glycol. DISCUSSION Over half of the "intermediates" from various stock collections and slightly less than half of those isolated from oysters, crabmeat and feces failed to utilize propylene glycol. Of the 42 strains isolated from milk and water 33 produced acid from propylene glycol. These variations and the differences observed from the Escherichia coli suggest that the ability to utilize propylene glycol is a strain characteristic. The source of isolation may play a part in the propylene-glycol activity of the organisms. Although several Escherichia coli in our stock collection produce acid from propylene glycol, of the 34 isolated from fresh material only one has this ability. More extensive studies of the action of Escherichia coli from a large number of sources will be necessary. The colon-typhoid group of organisms which yield lactic or formic acid from glucose might be expected to yield lactic, formic or propionic acids or possibly mucic, oxalic or acetic acids from propylene glycol. An attempt was made to identify the acid formed by these organisms from propylene glycol. The total acidity was approximately one half that yielded by glucose. One cubic centimeter of broth medium required 0.1 cc. N/10 NaOH for neutralization. Negative reactions were obtained for lactic, oxalic and mucic acids. No volatile acids were present, thus eliminating acetic or formic acids. SUMMARY 1. Because of the variation of reactions of Escherichia coli and the "intermediates" with propylene glycol, this method, in its present form, can not be used for differentiation.

5 FERMENTATION OF PROPYLENE GLYCOL A close correlation exists between the failure to utilize citrate and to forment propylene glycol by Escherichia coli. 3. A relationship between indol formation and propylene-glycol fermentation by Escherichia coli has been observed. REFERENCES Dozois, K. P., CARR, C. J., KRANTZ, J. C., JR., HACHTEL, F. AND BECK, F Sugar alcohols. VI. The utilization of sugar alcohols and their anhydrides by various microorganisms. Jour. Bact., 32, Standard Methods of Water Analysis American Public Health Association. 8th Edition, 270. Downloaded from on August 26, 2018 by guest