A Study of Micrococcus Zymogenes

Abstract

In 1899, MacCallum and Hastings isolated from the blood and organs of a person dying of acute endocarditis an organism which they described and named Micrococcus zymogenes. It produced tiny, smooth, glistening, white colonies on agar plate cultures. Morphologically the organism was found to be a minute coccus, often somewhat elongated, occurring in masses, singly, and in pairs or short chains of pairs. It was non-motile, non-encapsulated and Gram-positive. It grew well in glycerolor asciticfluid-agar and other nutrient media. Glucose and lactose were fermented with the formation of acid but no gas. Litmus was reduced. A thin, dirty white, pasty growth appeared irregularly on potato. No indol was formed in nutrient bouillon. The organism was a facultative anaerobe and resisted drying on agar slants for months.The proteolytic power of the organism was one of its most conspicuous properties. Gelatine was liquified, coagulated seruim was digested, and milk was first coagulated and then digested. The coagulation was thought to be due to a rennin-like enzyme, in part, at least. The changes produced in litmus milk were regarded as unusual and very characteristic. Sterile filtrates of broth cultures produced proteolysis similar to, but not so extensive as, that caused by the live organisms themselves.The micrococcus was found to be pathogenic for rabbits and white mice. Intraperitoneal injections of 0.3 to 0.7 cc. of broth

Streptococcus zymogenes

“…On the other hand, we have also studied the non-hemolytic S. liquefaciens obtained from other fecal sources and from milk. As has been previously shown, S. zymogenes and S. liquefaciens appear to be identical except in their actions on blood (Frobisher and Denny, 1928;Sherman and Stark, 1931).…”

Streptococci which Grow at High Temperatures

“…In1 a recent study of this organismn Frobisher and Denny (1928) conclude that it should be classified as a streptococcus, perhaps as a variety of Streptococcus l iquefaiens. Streptococcus glycerinaceus differs from Streptococcus fecalis in that it ferments glycerol and always ferments sucrose.…”

The Streptococci

“…Shortly after the work of MacCallum and Hastings, this organism was found in specimens from human autopsies by Harris and Longcope (1901), and since that time it has been reported occasionally from clinical and fecal sources. (Birge, 1905;Hicks, 1912;Torrey, 1926;Frobisher and Denny, 1928;Sherman and Stark, 1931;Torrey and Montu, 1934;Elser and Thomas, 1936; Although given the generic name Micrococcus by MacCallum and Hastings, this organism was early recognized as belonging to the genus Streptococcus (Winslow and Winslow, 1908) and most of the more recent investigators have so classified it.…”