IDENTIFICATION OF APYOCYANOGENIC STRAINS OF PSEUDOMONAS AERUGINOSA

Abstract

Only minimal differences between endogenous and glucose respiration were demonstrable with 0.03 M phosphate buffer at pH 7. The addition of 1 ml of trace metals (Table 1) or a modified Ringer's solution (Table 2) enhanced glucose respiration markedly. The a priori hypothesis that magnesium ions were largely responsible for this stimulation was tested by adding 1 ml of the trace-metal mixture and 38.2 mg MgSO4 .7H20 to 100 ml 0.03 M phosphate buffer at pH 7. This variation proved to be superior to the previous modifications, and RQ's within 5% of theoretical were obtained with several carbon sources. With this buffer, results represented in Fig. 1 and 2 were achieved. They indicate that several carbohydrates and inter-mediates of carbohydrate metabolism were oxidized by C. longisporum without immediate prior experience. Inspection of these curves also suggests the ability of the fungus to adapt to certain of these other substrates. It is noteworthy that earlier in this investigation phosphate concentration appeared not to influence the glucose respiration of C. Iongisporum. Exhaustive shaking of the mycelium in distilled water was required before the need for phosphate became manifest, suggesting intracellular metaphosphate stores. This study would suggest that other filamentous fungi may be studied similarly after their specific metal requirements for manometric work have been established.

Diagnostic Criteria for Differentiation of Pseudomonads Pathogenic for Man

“…General properties of the species: P. aeruginosa. Various studies (6,8,10,19,24) concerned with the characteristics of apyocyanogenic strains of P. aeruginosa have demonstrated that their identification can be based on growth at 42 C, oxidation of gluconate, positive oxidase reaction, and production of fluorescein. Other characteristics used to identify P. aeruginosa include acid production from carbohydrates (16), nitrate reduction, gelatinase activity (17), growth on cetrimide agar (4), demonstration of the arginine dihydrolase system, and the ability to assimilate various organic compounds as the sole sources of carbon and energy (21).…”

Acetamide Agar for Differentiation of Nonfermentative Bacteria

“…Acetamide preparations have been used as selective media for isolation of Pseudomonas aeruginosa from clinical materials (3, 6) or to assist in identification (1,2,4,5,7). Biihlmann et al (1) used an acetamide broth medium as a differential test to detect deamidation of acetamide by P. aeruginosa. This medium was a modification of Christensen urea agar; agar was eliminated and 1% acetamide was substituted for glucose and urea.…”

“…Assimilation studies by Gilardi (2) and others (7) using basal mineral media showed that acetamide was utilized by a wide variety of nonfermenting organisms. However, reports describing the ability of organisms other than P. aeruginosa (1) to deamidate acetamide are few (4,5).…”