Epidemic Pseudomonas aeruginosa serotype O16 bacteremia in hematology-oncology patients.

From 1 August 1978 through 31 December 1982, 98 hematology-oncology patients had positive cultures for Pseudomonas aeruginosa serotype O16; 22 of these patients developed bacteremia, and this bacteremia was associated with the occurrence of extensive perineal cellulitis in 10 patients (45.5%). Seventeen bacteremic patients died. The epidemic strain differed from other P. aeruginosa organisms isolated at the hospital by its resistance to all antibiotics available at that time (ticarcillin, piperacillin, azlocillin, tobramycin, ceftizoxime, ceftriaxone, moxalactam, ceftazidime, and fosfomycin). Univariate analysis showed the following factors to be significantly associated with P. aeruginosa O16 bacteremia: the severity of granulocytopenia at the time of the bacteremia, more days with fever, the administration of ticarcillin or an aminoglycoside, the receipt of a greater number of antimicrobial agents for a longer period of time before documentation of the bacteremia, and the occurrence of cellulitis. Logistic regression analysis showed that duration of fever, duration of bacteremia, and the number of antimicrobial agents administered before documentation of the bacteremia were the best predictors of P. aeruginosa O16 bacteremia. In a prospective study of the acquisition of P. aeruginosa by hematology-oncology patients, 1,149 specimens (throat and rectal swabs) from 270 patients and 201 specimens from their washbasin drains were collected. On only three occasions was the epidemic strain isolated from both the patient and his or her washbasin, but in each case the colonization of the patient preceded the isolation of the strain from the washbasin. The transmission of any P. aeruginosa organism from washbasin drain to patient could not be documented. Contact isolation precautions from the Centers for Disease Control were used for all hematology-oncology patients colonized or infected with P. aeruginosa after 7 January 1983. No case of P. aeruginosa O16 bacteremia has occurred at Hotel Dieu since July 1984.