Nutritional Requirements of Bacterium coliat 44 

Abstract

SUMMARY: A strain of Bacterium coli capable of growth in broth and in an ammonium +glucose + salts medium at 37' and in broth at M', died in the defined medium at 4 4 ' . The addition of glutamic acid to this medium allowed the growth temperature to be raised slightly ; the further addition of nicotinamide allowed a further increase in growth temperature.One of the criteria on which Public Health bacteriologists rely to identify strains of Bacterium coli as being of faecal origin is the ability to ferment lactose with the evolution of gas in a bile salt medium a t 44". The experiments recorded in this paper show that ability to multiply a t 44" depends not only on the strain of Bact. coli but also on the nutritive materials supplied. METHODSThe defined medium used throughout the work was Bigger's (1950) modification of Gale's (1947) medium which contains only organic salts and glucose, the sole nitrogen source being ammonia. Broth, where used, contained 1 yo Lab-Lemco and 1 yo peptone. Experiments were carried out with 5 ml.volumes of medium in small glass bottles covered with loosely fitting aluminium caps. When other substances were required in the medium, additions were made either in bulk or by adding to the individual bottles a sufficient number of drops (Dreyer pipette) of a suitable dilution of the substance. Serial dilutions, to halve the concentration of a substance, were made by transferring 5 ml. amounts from bottle to bottle. Bact. coli strain no. 18 was used as test organism, except in certain experiments designed to determine whether the phenomenon described occurred with other strains of Bact. coli. The cultural characteristics of Bact. coli strain no. 18, which was isolated from faeces, are given in Table 4. Inoculation was, in all cases, carried out by adding to 5 ml. of the medium, one drop (Dreyer pipette) of a 1/10,000 dilution in buffered saline of the test organism grown in defined medium at 3 7 ' . Cultures were examined every 24 hr. during incubation. One 5 mm. loopful of each culture which had remained clear was spread over the surface of an agar slope, which was examined after 24 hr. incubation, to determine the colonies resulting from the viable organisms in the original culture. RESULTSGrowth curves were obtained from viable counts (2 hr. intervals) on Bmt. coli growing in defined medium or in broth at 37 and 44". It was found that whereas the organism multiplied freely in both media a t 37" and in broth a t 44", it died when exposed to 44" in defined medium. The effect of adding certain

The Effect of Temperature on the Nutritional Requirements of Facultative and Obligate Thermophilic Bacteria

“…Similar studies of the effect of the temperature of incubation on nutritional requirements have been made on nonmutant strains of Lactobacillus arabinosus by Borek and Waelsch (1951), on Esherichia coli by Ware (1951), and on Pasteurella pestis by Hills and Spurr (1952). In general the findings of these workers have shown that at the higher incubation temperatures the organisms under study required additional metabolites for growth.…”

Nutrition of the Acetic Acid Bacteria

“…Substitution of pyridoxamine for pyridoxine eliminates the requirement of Lactobacillus delbrUeckii for lysine, threonine, and alanine (Stokes and Gunness, 1945), and biotin eliminates the need for aspartic acid in the case of Lactobacillus arabino&us and other lactic acid bacteria (Stokes, Larsen, and Gunness, 1947). Recently Ware (1951) has found that although ammonium nitrogen is adequate for the growth of Escherichia coli at 37 C, glutamic acid and nicotinamide must be supplied for growth at 44 C.…”

An improved formate lactose glutamate medium for the detection ofEscherichia coliand other coliform organisms in water

“…Other factors tested and discarded were nicotinamide, riboflavine, pyridoxine, cyanocobalamin, and para-aminobenzoic acid. The inclusion of nicotinic acid in the formula resulted less from benefits observed at 370 C. than from the observations of Ware (1951) that nicotinamide (or nicotinic acid) was an essential nutrient for some strains of Esch. coli to produce fermentation at 440 C.…”