From Nov. 15 to Dec. 17, 1977, Pseudomonas cepacia was isolated from the blood of 16 patients in Odense, Denmark, and Nijmegen, Holland, 2--5 days after an operation with general anaesthesia. The fever started 14--70 h after operation and lasted 2--4 days. All patients recovered. 14/15 patients examined 7--51 days later had agglutinating antibody titres of 400-3,200 against the epidemic strain. Ps. cepacia with identical biochemical characters and sensitivity pattern was isolated from unbroken vials containing the anaesthetic fentanyl, which had been given to all 16 patients. Two batches were contaminated, one heavily so (10(4)--10(5) cfu/0.1 ml). Seven other batches examined yielded no growth. The preservative added to the vials was a mixture of methyl- and propyl-p-hydroxybenzoates which not only allowed growth of the Ps. cepacia strain but could also serve as a carbon source as did citric and malonic acids. The concentration of preservative was not reduced in contaminated vials. The vials had not been sterilized after closure; too much reliance had been placed on an aseptic technique and insufficient preservatives.

In November‐December 1977 an epidemic of bacteræmia due to P. cepacia was observed in Odense, Denmark (nine patients), and in Nijmegen, Holland (seven patients). All patients recovered. The epidemic was traced to intrinsic contamination of two batches of the anæsthetic fentanyl. All isolates from the patients and from the two batches belonged to the same biotype, had identical sensitivity patterns, and identical antigens. The P. cepacia strain differed from stock strains in being able to grow in two passages in methyl‐p‐hydroxi‐benzoate, 0.5 mg/ml, which promoted the growth of the microorganism; inocula of 2–20 cfu were sufficient to initiate growth in the drug or preservative. These facts indicate the inadvisability of using p‐hydroxi‐benzoates as preservatives in vials. The strain was inhibited at temperatures above 38.5°C, corresponding to the recovery of the patients after a period with fever above 39°C. Fourteen out of 15 patients examined had agglutinin titres ≥ 320, while 36 blood donors had titres <40. Of 12 patients with postoperative fever in the same period whose blood cultures did not yield P. cepacia, three had titres >320.