Lowell A. Rantz

A Modification of the Technic for Determination of the Antistreptolysin Titer.

Summary 1. A modified technic for the determination of the antistreptolysin titer of serum has been described which involves the use of a concentrated lysin reduced to the active form at the time of use.

The importance of sample size in studies based upon the serologic classification of escherichia coli.

Summary The total number of different serological O groups in individual specimens was determined by a study of Escherichia coli isolated from feces, urines, the vagina, and blood. The serologic heterogeneity of the fecal coliform flora was confirmed. Ninety percent of urines contained only a single E. coli group regardless of the number of organisms present. The vaginal flora was composed of a single group less frequently than the organisms isolated from urine, but was not so heterogenous as that of the feces. E. coli recovered from blood was invariably of a single group. The importance of sample size was demonstrated in the study of stool specimens. Most O groups present were identified by an examination of only 5 colonies but the possibility of identifying additional strains was not exhausted by a study of as many as 25 colonies. The chances of finding new O groups by a study of more than 5 colonies were greater in those specimens that initially contained more than one O group.

Relation of a Specific Strain of Salmonella to Ulcerative Cecitis of Rats

Summary 1. A specific strain of salmonella has been invariably obtained on culture from the ulcers of rat cecitis, 2. Salmonella were not obtained from the cecum in the absence of lesions with one exception. 3. Agglutinins for the specific strain of salmonella are found in most of the rats in this colony although the titer is on the average higher in animals with visible cecitis. 4. Feeding the specific salmonella in appropriate doses was followed after a long latent period by development of cecitis in many of the test animals. 5. The association of some other synergistic agent is not fully excluded but seems at present unlikely.

Sulfonamide and penicillin resistance of group A hemolytic streptococci.

Summary Strains of certain types of Group A hemolytic streptococci were discovered to be naturally resistant to moderate amounts of sulfadiazine. It is suggested that such organisms originated the epidemics of streptococcal disease among troops receiving sulfonamide prophylaxis, later becoming more resistant by mutation. No strains significantly resistant to penicillin were discovered.

Failure of certain growth factors to inhibit sulfonamide bacteriostasis in simple media.

Summary and Conclusions Nicotinic acid, thiamin chloride, cocarboxylase, riboflavin, pyridoxine and para-amino benzoic acid have been shown to have no effect on the photometrically determined growth rate of S. aureus and E. coli in simple media. Calcium pantothenate definitely accelerated the rate of multiplication of S. aureus but not of E. coli when present in a concentration of 200 μg per milliliter. None of these substances except para-amino benzoic acid antagonized sulfathiazole bacteriostasis although present in amounts 40 times as great as the sulfonamide. Concentrations of sulfonamide 2,500 times that of the accompanying para-amino benzoic acid were completely ineffective in inhibiting bacterial growth. These observations, therefore, support the view that the sulfonamides directly affect that part of the microbial metabolic system which specifically utilizes para-amino benzoic acid, since relatively large amounts of 6 other important growth factors completely failed to inhibit their bacteriostatic activity.

Renal Clearance of Oxacillin.

Conclusion The renal clearance of oxacillin has been determined in normal males and found to be approximately 45% that of penicillin G. Implications regarding protein binding of oxacillin are discussed.