Escherichia coli O157:H7 diarrhea in a nursing home: clinical, epidemiological, and pathological findings.

In September 1984, an outbreak of Escherichia coli O157:H7 infection occurred in a nursing home. It was the first recognized outbreak of this organism in the United States since 1982, when two outbreaks led to its recognition as a pathogen. Thirty-four of 101 residents developed a diarrheal illness; 14 were hospitalized with a severe illness characterized by crampy abdominal pain, marked abdominal distention, and grossly bloody diarrhea, and four died. The spectrum of illness associated with the infection was broad and included the following: asymptomatic infection, nonbloody diarrhea, hemorrhagic colitis, hemolytic uremic syndrome, and death. Clinical, radiographic, and postmortem pathological findings suggested involvement of the cecum and right colon. No evidence of response to antimicrobial agents could be documented, and antidiarrheal agents may have aggravated the disease. This investigation implicated hamburger as the vehicle transmission. Seventeen of 19 residents with hemorrhagic colitis, but only 28 of 67 healthy residents, had eaten hamburger on 13 September (P less than .001, Fisher's two-tailed exact test; relative risk [RR] = 7.7). Infection with E. coli O157:H7 can cause a wide range of manifestations. In the elderly these can be particularly severe and may resemble ischemic colitis.

Effect of ketoconazole and amphotericin B on encapsulated and non-encapsulated strains of Cryptococcus neoformans.

Growth inhibition studies were done on an encapsulated and non-encapsulated strain of Cryptococcus neoformans at the minimal inhibitory concentration and one-half the minimal inhibitory concentration of ketoconazole and amphotericin B alone and in combination. Growth of both strains was significantly inhibited by ketoconazole, amphotericin B, and the combined drugs at the minimal inhibitory concentration of each drug over a 5-day period. Calculation of the expected inhibition of growth for both strains with both drugs showed antagonism at 24 h followed by an additive effect and synergy for the remaining 4 days of the assay. Although similar results were obtained for both strains with one-half the minimal inhibitory concentration, an additive effect was observed with the drug combination at 24 h for the encapsulated strain, and an antagonistic effect was observed with the non-encapsulated strain.

Green algal infection in a human.

Infection by unicellular green algae has not been described in humans. A case is reported in a 30-year-old woman who developed persistent infection of a healing operative wound on the dorsum of the right foot, after possible contamination by river water while canoeing. The wound was debrided 2 months later. Histologically, infected tissues contained mixed suppurative and granulomatous inflammation associated with endosporulating, round to oval microorganisms, ranging from 6-9 microns in diameter. Many of these organisms contained multiple, strongly periodic acid-Schiff, Gomori methenamine-silver, and Gridley fungus-positive granules in the cytoplasm. The organisms in tissue did not stain with fluorescent antibody conjugates specific for the two known pathogenic Prototheca species. In some organisms, electron microscopy revealed membranous cytoplasmic profiles considered to be remnants of degenerated chloroplasts. These findings are consistent with the presence of a green algal infection.