Granulomatosis infantiseptica.

Abstract

Pneumonia accounts for approximately 90 per cent of fatal neonatal infections (3). The purpose of this paper is to alert the radiologist to granulomatosis infantiseptica, another disease entity producing a miliary pattern in the neonatal lungs. The causative organism is Listeria monocytogenes. The incidence of Listeria monocytogenes infection in human subjects has been considered sporadic, but recent evidence from Germany indicates a greater frequency (15). The condition has not been of great concern to clinicians, especially in this country, until relatively recent times (8, 13, 21). Reviews in the American literature of the last decade have emphasized its importance (6, 11, 21), but we have been unable to find reference to this entity in the radiologic literature. Bacteriology Frequently, Listeria is erroneously identified as a diphtheroid and is discarded as a contaminant. The organism is a small, aerobic, Gram-positive, somewhat pleomorphic, non-spore-forming, motile bacillus measuring approximately 0.5 micron in width by 1.0 to 3.0 microns in length. The bacteria have a tendency to arrange themselves in palisade formation, and thread-like chains of organisms maybe observed in rough cultures. Listeria attacks glucose, esculin, and a few other sugars, with the formation of acid, but not gas. The colonies, when grown on blood agar, are surrounded by a narrow zone of beta hemolysis. On tellurite medium, colonies are black, smooth, and circular (8,21,22). Listeria monocytogenes was first isolated from laboratory guinea-pigs and rabbits by Murray et al. in 1926. The monocytosis provoked in the rabbit is responsible for the designation “monocytogenes” (16). In 1929, Nyfeldt recovered the organism from the blood stream of a boy with infectious mononucleosis, this being the first recognized isolation of Listeria from a human subject (17). Gill, the first to recognize the disease in domestic animals, isolated the organism from encephalitic sheep in 1931 (5). Six types of Listeria infection have been described in man: (1) granulomatosis infantiseptica; (2) septic type with mononucleosis; (3) septic typhoid form; (4) infection of the central nervous system; (5) listeriosis in pregnancy; (6) oculoglandular form. Natural History Granulomatosis infantiseptica is an intrauterine infection with a high fetal or neonatal mortality but a very low mortality for the mother. In the fetus the infection is generalized but is characterized by extensive focal necrosis with a monocytic infiltration of the liver, spleen, and more rarely of the lungs and intestines. There is associated meningitis in some cases (4). In severe cases, Listeria may be isolated without difficulty from blood, cerebrospinal fluid, urine, and other secretions. Potel has observed that the meconium in such cases is always positive, perhaps due to the swallowing of infected amnionic fluid (19).