Demonstration of Transmission of an Acinetobacter baumannii Outbreak Between Intensive Care Units Using AP-PCR Method

Introduction: In recent years, multidrug-resistant Acinetobacter baumannii has become more prevalent. Patients, especially in the intensive care units (ICU), may be colonized in a very short period, and then they develop a severe infection with a high mortality rate, such as bacteremia, pneumonia, surgical site infections. The aim of our study was to analyze the A. baumannii outbreak using Arbitrarily Primed-Polymerase Chain Reaction (AP-PCR) method which shows transmission between ICUs. Materials and Methods: Health care associated infections (HAI) in our ICUs are followed by active prospective surveillance. The diagnosis of HAI was made according to Centers for Disease Control and Prevention (CDC) criteria. An outbreak investigation was started upon clustering in A. baumannii infections by Infection Control Committee. In the microbiological part of the outbreak investigation, a molecular analysis, AP-PCR method, was used to show a clonal relationship among the strains. The isolated strains was stored in -80°C in microbanks until the study. Results: At fi rst, an outbreak that started from a patient who died due to A. baumannii infection and included 8 patients was detected in the surgical ICU between 17th August 2013 to 18th October 2013. In this period, two patients in the surgical ICU were transferred to the anesthesiology ICU. After the transfer of the patients (13 September 2013), an outbreak occurred which included 12 patients in the anesthesiology ICU. Mainly two A. baumannii clones (A and B) were described by AP-PCR method, and transmission from the patients who transferred from surgical ICU was demonstrated. Conclusion: In this study, an outbreak due to two clones of A. baumannii was shown using clinical data and molecular investigation of isolates in two different ICUs (surgical ICU and anesthesiology ICU). Patient transfer between the units can cause outbreaks, therefore, implementation of infection control measures are important on admission. The outbreak ended with the collaboration of both surgical and anesthesiology ICU directors and employees. Molecular analysis is seen as an important method to show presence of an epidemic and provides a valuable data discovering of the source in hospital setting