626 MICROCOCCUS, SARCINA, RHODOCOCCUS AND LEUCONOSTOC 



Metabolic and Biochemical Activities. — Aerobic, facultatively anaerobic. Optimum tem- 

 perature for growth 22-30° C. Pigment formed most readily at 22° C. No hsemo- 

 lysin formed. Ferments no sugars. L.M. unchanged. M.R. — . V.P. — . M.B. 

 reduction — . 

 Pathogenicity.- — ^Non-pathogenic. 



Sarcina lutea Schroeter.^ — This organism, which was described by Schroeter (1875) 

 as the Bacteridium aurantiacum, is a Gram-iJositive sarcina, giving a chrome-yellow 

 growth on culture media. On agar the colonies are raised, yellow, coarsely granular, 

 with an entire margin and a moist gUstening surface. On potato they are dry, dull and 

 granular. In broth there is an abundant yellow sediment with no turbidity. The opti- 

 mum temperature of growth is 25° C. It is found in air, soil and water. 



Sarcina aurantiaca Fliigge. — Described by Fliigge (1896). Gram-positive spheres 

 developing in packets. On gelatin plates forms slowly-growing orange-yellow colonies 

 gradually liquefying gelatin. On agar slope, gives a thick reddish-yellow growt*h com- 

 posed of single colonies ; similarly on potato. In broth gives a turbidity with abundant 

 sediment. Grows best at room temperature. Found in air and water. 



Sarcina ureae Beijerinck (1901) is a spherical organism, 0-7-1 -2 fx in diameter, occurring 

 singly, in pairs, and in packets. Said to be motile by peritrichate flagella and to form 

 spores. Gram-positive. Resists heating to 100° C. for 5 minutes. Gelatin not liquefied. 

 Found in stale urine (see Gibson 1935). 



Sarcina conjunctivaB Verderame.— Isolated by Verderame (1911) from the conjunc- 

 tival sac of a girl suffering from acute conjunctivitis. Named by him Sarcina con, 

 junctivce citrea. Is stated to be Gram-negative. On agar after 24 hours the colonies 

 are pinhead in size, round, bright-yellow, opaque, with an entire edge, and of butyrous 

 consistency ; after 48 hours they are 4 mm. in diameter and lemon-yellow in colour. On 

 an agar slope there is a thick creamy layer of growth after 2 days. Similar growth, but 

 more abundant on ascitic agar. In gelatin stab there is a surface growth of 2-3 mm. 

 in diameter after 24 hours, and a filiform growth of fine, light, greyish-yellow, opaque 

 colonies ; no liquefaction. On potato an abundant, creamy, lemon-yellow growth of 

 rather dry appearance. In broth after 24 hours there is a very light turbidity, with a 

 suspension in the liquid of fine flocculi wliich are easily broken up on shaking, and a cloudy 

 viscous deposit of light yellow colour. Optimum temperature 37° C., but grows well 

 at 14-18° C. Facultative anaerobe. Forms acid in glucose, Isevulose, maltose, lactose, 

 sucrose and inulin, not in mannitol or galactose. H2S positive. Indole negative. Nitrates 

 not reduced. Non-pathogenic to mice or guinea-pigs. 



Numerous other sarcinse have been described, such as Sarcina citrea Menge in 1892, 

 and an unnamed Gram-negative Sarcina isolated by Nagano (1902) from the pus of 

 an ovarian abscess. 0rskov (1930) draws attention to a sarcina found in the mouth and 

 throat which, though non-motile itself, gives rise to motile cocci, each provided with a 

 flagellum. The cocci themselves are not reproducible. For this remarkable organism 

 the name Sarcina mirabilis is suggested. 



Rhodococcus 



Definition.- — Rhodococcus. 



Spherical or ovoid cells occurring in groups or regular packets. Usually Gram- 

 positive, but are easily decolorized. Growth on agar abundant with formation of 

 red pigment. Weak fermentative powers. Gelatin rarely liquefied. Nitrates 

 generally reduced. Saprophytes. 



Type species is Rhodococcus rhodochrous Zopf. The term Rhodococcus was first 

 introduced by Zopf in 1891 (see Buchanan 1925). 



Rhodococcus rhodochrous Zopf. — Found in water. Spherical organism, about 0-8-1 ju 

 in diameter, occurring singly, in pairs and in small groups. Gram-positive. Gives a 

 confluent, raised growth of a carmine hue on agar. Thick, rose-red pellicle in broth, 



