Berenice M. Thomason

Fatal Pneumonia Caused by Legionella pneumophila, Serogroup 3: Demonstration of the Bacilli in Extrathoracic Organs

An immunosuppressed patient with malignant lymphoma died of acute pneumonia caused by Legionella pneumophila. Bacilli of serogroup 3 were detected in areas of pnemonia, in a mediastinal lymph node, and in the liver and spleen by direct immunofluorescence done on tissue obtained at autopsy. That the extrathoracic fluorescent material represented intact bacteria rather than antigenic fragments or antigen-antibody complexes was confirmed by finding intracellular bacilli in the liver by electron microscopy. To our knowledge, this case represents the first example of fatal disease attributed to serogroup 3 L. pneumophila and the first case in which L. pneumophila has been demonstrated in extrathoracic organs.

DETECTION OF SALMONELLAE IN FOODSTUFFS, FECES, AND WATER BY IMMUNOFLUORESCENCE

The major impetus for development of polyvalent Salmonella immunofluorescent ( IF) reagents has come from the food industries and from the regulatory agencies charged with insuring a safe food supply. Among the gram-negative bacteria, the salmonellae probably produce more infections in more species of animals in more geographic areas of the world than any other organism. In the United States alone, it has been estimated that reported isolations of Salmonella account for only about 1% of the actual human cases.j5 Because approximately 25,000 isolates are reported annually, the morbidity may easily reach 2,500,000 cases.36 Protection against infection by the salmonellae encompasses the provision of pure food and water and interruption of the direct and indirect fecal-oral transmission routes. If consumers are t o be protected from infection, mass-produced foods, such as meat, fish, dairy products, and processed foods, derived from these sources must be monitored for the presence of these ubiquitous organisms. The cost of conventional cultural procedures for isolation and identification of the salmonellae was estimated in 1971 by the U.S. Department of Agriculture (USDA) and by the Food and Drug Administration (FDA) t o be about 5-7 dollars per sample. The use of I F tests for mass screening of foodstuffs and water offers an economic alternative to conventional procedures.

Preparation and testing of a polyvalent conjugate for direct fluorescent-antibody detection ofLegionella pneumophila

A polyvalent conjugate forLegionella pneumophila, the Legionnaires’ disease bacterium, was prepared by combining monospecific antibodies for the four recognized serogroups ofL. pneumophila. Pure cultures ofL. pneumophila and other bacteria representing 18 genera and 50 species of heterologous organisms were used in evaluating the reagent. A total of 358 specimens from patients suspected of having Legionnaires’ disease also were tested. The results show the practicality and advantages of using a polyvalentL. pneumophila conjugate for screening clinical specimens.

TATLOCK Bacterium (Pittsburgh Pneumonia Agent) Presumptively Identified in Five Cases of Pneumonia

Excerpt Recently Rogers and co-workers (1) described five cases of pneumonia caused by a bacterium that could not be isolated on routine bacteriologic media. They suggested that the organism might ...