Pseudomonas aeruginosa

Pseudomonas aeruginosa

Southern Society for Clinical Research 654 ment of patients first observed late in the course of disease. The results of cortisone in this limited s...

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Southern Society for Clinical Research

654

ment of patients first observed late in the course of disease. The results of cortisone in this limited series of patients warrant further clinical testing. ENDOCRINE

ACTIVITIES

IN

THE

CONTROL

OF

James T. Wortham (by invitation) and Benjamin B. Wells. (From the Department of Medicine, University of Arkansas School of Medicine, Little Rock, Ark.) In performing urine concentration tests with [email protected] variability in the results was discovered in normal subjects. Standardization of test conditions yielded results as follows: Normal females were given pitressin tests under several controlled conditions. While at rest the subjects concentrated to 1.026 or above consistently whether they had been previously fasted or not. Moderate, forced exercise during the test abolished the pitressin effect on urine concentration. Likewise, small amounts of water given before the test resulted in significant abolition of the pitressin effect. Since pitressin is physiologically identical with the antidiuretic hormone of the posterior pituitary (ADH), it seems evident that water diuresis is significant in opposing ADH effect but that some factor inherent in physical activity is more potent in opposing ADH effect. Adrenal cortical steroids are under study for this anti-ADH effect. Moderate doses of desoxycorticosterone acetate were given two hours before a pitressin test. It was found that the pitressin effect was abolished. The pitressin test was performed, theoretically, while renal tubules were under the influence of DOCA but before any significant shift in fluid compartments could have occurred. Other steroids under study promise to reveal significant effects. An attempt is being made to determine whether exercise opposes the ADH effect through adrenal cortical activation. RENAL

TUBULAR

CONCENTRABILITY.

COMPARISON OF THE ACTION OF VARYING CENTRATIONS

OF

EIGHT

ANTIBIOTICS

CON-

AGAINST

AERUGINOSA. Ellard M. Yow. (From the Department of Internal Medicine, Baylor University College of Medicine, Houston, Tex.) The resistance of most strains of Pseudomonas aeruginosa to the action of the commonly used antimicrobial agents has increased its relative importance and frequency as a causative agent in infectious processes. This study was undertaken in an effort to determine the most effective therapy against infections due to this microorganism. Fifty-four strains of pseudomonas recently isolated from patients were tested for sensitivity by the tube dilution technic to varying concentrations of penicillin, streptomycin, bacitracin, neomycin, aureomycin, chloramphenicol, terramycin and polymyxin B. At an antibiotic concentration of 15.6 pg./ml., all of the strains tested were sensitive to polymyxin B, 57 per cent were sensitive to neomycin, 55 per cent to terramycin, 42 per cent to streptomycin, 8 per cent to aureomycin, 2 per cent to chloramphenico1 and none of the strains was sensitive to penicillin or bacitracin. At a level of 1.0 pg./ml., 62 per cent of the strains tested were sensitive to polymyxin B, 6 per cent to streptomycin, but none were sensitive to the other antibiotics studied. A comparison of the sensitivity at other levels was made and the significance of such determinations on the clinical administration of these antibiotics is discussed. A similar study was performed using the disk sensitivity technic against 100 strains of pseudomonas. A comparison of the results obtained by the two methods revealed a relatively close qualitative but not quantitative correlation. Thirty-eight patients with pseudomonas infections were treated. Polymyxin B was the most consistently effective antibiotic clinically although terramycin favorably influenced the course of the infection when the causative organism was sufficiently sensitive. PSEUDOMONAS

AMERICAN

JOURNAL

OF

MEDICINE