Acinetobacter calcoaceticus anitratus outbreak in the intensive care unit traced to a peak flow meter

A cluster of seven cases of Acinetobacter caleoaceticus anitratus in a community teaching hospital intensive care unit was discovered (the seventh case was located in a step-down unit next to an infected patient recently transferred from the intensive care unit.)

An outbreak investigation, including detailed epidemiologic, clinical, and laboratory investigation, was performed.

A single strain of A. calcoaceticus anitratus was responsible for infection in all seven patients. All patients had tracheostomies, were in respiratory failure, and were ventilator dependent. Patients ranged in age from 27 to 81 years. No common causative variable or explanatory findings were present except that the same peak flow meter (manual weaning criteria machine) was used to facilitate weaning all seven patients from mechanical ventilation. Culture of the mouthpiece isolated a A. calcoaceticus anitratus strain with the identical susceptibility pattern and biochemical profile as that from the infected patients.

A. calcoaceticus anitratus was transmitted by a peak flow meter nosocomially to seven patients receiving mechanical ventilation. Disposable mouthpieces were introduced to prevent cross-contamination. A 2% glutaraldehyde solution was used to disinfect the machine between uses. No further outbreaks of A. calcoaceticus anitratus pneumonia were identified during 3 years of follow-up.