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Endemic Acinetobacter anitratus in a surgical intensive care unit: mechanical ventilators as reservoir
C M Vandenbroucke-Grauls1, A J Kerver, J H Rommes
1Department of Clinical Microbiology and Laboratory of Infectious Diseases, University Hospital, Utrecht, The Netherlands.
Abstract:
Colonization and infection with an endemic multiresistant strain of Acinetobacter calcoaceticus variety anitratus had been observed in the surgical intensive care unit of a university hospital since 1982. An outbreak of infection with this endemic, multiresistant Acinetobacter anitratus strain occurred between January and September, 1984. After initial attempts at identification of environmental reservoirs had been unsuccessful, risk factors for the acquisition of Acinetobacter anitratus were investigated by comparing the epidemiological characteristics of patients who became colonized or infected with those of control patients without colonization. The results of this case-control study and of the ensuing specific cultures indicated that ventilators in use in the unit were the reservoirs of Acinetobacter anitratus, resulting in frequent nosocomial respiratory tract infections. After modification of the mechanical ventilators, colonization and infection rates with Acinetobacter anitratus decreased. Since January 1985, no new cases of colonization or infection with this endemic strain of Acinetobacter anitratus have been recorded.
Insights
Mechanical ventilators were identified as the source of Acinetobacter calcoaceticus variety anitratus outbreaks in a surgical ICU. Modifying ventilators significantly reduced infection rates, controlling the endemic strain.
Area of Science:
- Infectious Diseases
- Hospital Epidemiology
- Microbiology
Background:
- An endemic, multiresistant strain of Acinetobacter calcoaceticus variety anitratus caused persistent colonization and infection in a university hospital's surgical intensive care unit since 1982.
- An outbreak of Acinetobacter anitratus infection occurred between January and September 1984, necessitating an investigation into its source and transmission.
Purpose of the Study:
- To identify the environmental reservoirs and risk factors associated with the acquisition of Acinetobacter anitratus in the surgical intensive care unit.
- To investigate the cause of frequent nosocomial respiratory tract infections linked to this multiresistant strain.
Main Methods:
- A case-control study was conducted, comparing epidemiological characteristics of colonized/infected patients with uninfected controls.
- Specific cultures were performed following initial unsuccessful environmental reservoir identification.
- Mechanical ventilators were investigated as potential reservoirs.
Main Results:
- The case-control study and subsequent cultures identified mechanical ventilators as the primary reservoirs for Acinetobacter anitratus.
- These contaminated ventilators were linked to frequent nosocomial respiratory tract infections.
- Modifications to the mechanical ventilators led to a decrease in colonization and infection rates.
Conclusions:
- Mechanical ventilators served as the source of endemic, multiresistant Acinetobacter anitratus infections in the surgical intensive care unit.
- Targeted modifications of ventilators effectively controlled the outbreak and reduced infection rates.
- No new cases of colonization or infection with this strain were recorded after January 1985, indicating successful intervention.