Habitat: Occurs in large numbers in preputial secretions of dogs. 14. Haemophilus citreus Diernhofer, 1949. (Wiener tierarztl. Monatsschr., 36, 1949, 582.) cit're.us. L. adj. citreus of the citron; M.L. adj. citreus lemon-colored. Rods, 0.5 by 1.0 to 2.0 microns, occurring singly and in short chains; frequently' pleomorphic with long threads. Non-motile. Stain poorly and unevenly, showing bi- polar bodies. Gram-negative. Gelatin plus blood: No liquefaction. Plain agar: No growth. Blood agar containing 20 to 30 per cent blood and 1.0 per cent glucose is optimum for isolation. Colonies are 1 to 2 mm in diameter, flat, moist and entire. Some strains produce a narrow zone of hemolysis around the colonies. Become slightly yel- low; lemon-yellow when massed by loop. V and X agar colonies: Very small, trans- parent, colorless. Serum, pus, fresh milk, potato extract and yeast extract added to chocolate agar stimulate luxuriant growth. Indole is produced. Weak acid from glucose. Nitrites produced from nitrates. Non-pathogenic for mice, guinea pigs and calves. Does not induce disease in the genital tracts of cattle. Aerobic. Grows at 37° C. Killed in 30 minutes at 50° C. Source: Isolated from genital secretions from acute and chronic cases of vesicular exanthema (exanthema coitale) in cattle. 15. Haemophilus pisciuin Snieszko et al., 1950. (Snieszko, Griffin and Friddle, Jour. Bact., 59, 1950, 699.) pis'ci.um. L. noun piscis fish; M.L. gen. pi. noun piscium of fishes. Rods, in lesions measuring 0.5 to 0.7 by 2.0 microns, in cultures measuring 0.8 to 1.0 by 1.0 to 3.0 microns, occurring singly, in pairs, in irregular groups and occasionally as filaments up to 12.0 microns in length. Non-motile. May show bipolar staining. Gram-negative. Requires diphosphothiamine or adenosine triphosphate for growth (Griffin, Arch. Biochem., 30, 1951, 100). Supplied by peptic digest of fish tissue or 5 per cent sterile, unheated potato extract; V and X factors are not required. X in presence of diphos- phothiamine increases growth response (Griffin, Yale Jour. Biol, and Med., 24, 1952,411). Fish e.xtract gelatin colonies : Same as on agar. No liquefaction. Fish extract gelatin stab: Growth best near surface, filiform. No liquefaction. Fish extract agar colonies: 1 to 3 mm in diameter, circular, entire, convex, opaque, smooth, cream-colored. S variants are butyrous, R variants are compact and tough. Blood agar: Beta hemolysis. Fish extract agar slant: In 2 to 3 days, growth is filiform, slightly glistening, cream-colored. S variants are butyrous, R variants are brittle. Fish extract broth: R variants show transient clouding, then granular; adherent to walls; clearing of medium; scant pellicle or ring within a week. S variants remain uniformly clouded for several days. Fish extract litmus milk: No change. Potato: No visible growth. Indole not produced. Acid but no gas in 2 to 3 days in fish extract broth with glucose, fructose or sucrose; slowly with maltose, trehalose or starch; weak and slowly with mannose, galactose, cellobiose or dextrin. No acid with arabinose, xylose, rhamnose, lactose, melibiose, raffinose, melezitose, inulin or alcohols. Methyl red test positive; Voges- Proskauer test negative after one week. Fish extract used in media. Nitrites produced from nitrates. Aerobic, facultatively anaerobic. Optimum temperature, between 20° and 25° C. No growth at 35° C., slow growth at 7° C. Pathogenic for trout. Source: Isolated from trout with ulcer disease. Habitat : Found in infected trout. A cause of ulcer disease in trout.
