Roger A. Feldman

Human-to-Human Transmission of Pseudomonas pseudomallei

Melioidosis, the clinical manifestation of infection with Pseudomonas pseudomallei, has occurred infrequently in American citizens; almost all reported cases have been in Vietnam veterans, usually associated with respiratory disease. A Vietnam veteran from Mississippi developed chronic prostatitis, with no other clinical manifestations, during service in Vietnam, and P. pseudomallei was isolated from prostatic secretions 2 years after his return to the United States. The patient had had sexual contact with four women including his wife since his return from Vietnam. Vaginal and cervical cultures and serum samples were obtained from the four women, and serum samples and cultures of semen were obtained from the patient. Vaginal swabs and semen cultures were negative for P. pseudomallei. The patient and his wife had hemagglutination titers (greater than 640) diagnostic of P. pseudominallei infection. This occurrence of venereal transmission is the first report of person-to-person spread of P. pseudomallei infection.

Nursery salmonellosis: delayed recognition due to unusually long incubation period.

A nursery outbreak of diarrheal illness caused by Salmonella nienstedten initially involved seven infants cared for in one nursery; secondary infection subsequently affected one infant cared for in the same nursery as well as four other infants. Recognition of the outbreak was delayed due to an unusually long incubation period. The period from last known exposure to onset of diarrhea ranged from two to 18 days, with a median of ten days. The prolonged incubation period may have resulted from a low inoculum of the organism, from a previously unknown characteristic of Salmonella nienstedten, or may be an age-specific response. Hospital infection control personnel should be aware that nosocomial cases of salmonellosis may have a longer incubation period than has been previously recognized.

Epidemiology of Salmonella and Shigella Infections in the United States

The epidemiologic characteristics of Salmonella and Shigella infections in the United States have been studied by examination of data from 3 major sources: a national laboratory-based surveillance system, outbreak investigations, and carefully designed field studies. In this presentation we will separately discuss Salmonella and Shigella infections and for each give examples of contributions from these 3 sources that have allowed identification of specific problems and development of appropriate control measures.