Analysis of Acinetobacter baumannii hospital infections in patients treated at the intensive care unit of the University Hospital, Wroclaw, Poland: a 6-year, single-center, retrospective study

Background: Acinetobacter baumannii (AB) is one of the most frequently isolated strains of bacteria in intensive care unit (ICU) patients, which provides huge therapeutic problems due to its multidrug resistance (MDR). Patients and methods: The overall purpose of the study was analysis of health care-associated infections in terms of the incidence of AB strain infections and the changing susceptibility of this strain within a 6-year observation (2011-2016). The study was carried out in an ICU of the University Hospital in Wroclaw (Poland). Results: Among 589 isolated strains responsible for 540 health care-associated infections (21.2%) in 2549 ICU patients, AB was the pathogen in 183 (31%) cases. The incidence of AB infection amounted to 6.4/1000 patient-days. An increase was noted in the total number of hospital infections caused by AB strain from 16.5% and 3.39/1000 patient-days in 2011 to 41% and 9.64/1000 in 2016 (p=0.0003 and p=0.000, respectively). AB infections most frequently concerned ventilator-associated pneumonia (73.8%). AB was susceptible to colistin, amikacin, imipenem, meropenem, and ciprofloxacin in 100%, 10.7%, 12.3%, 11.5%, and 2.4% respectively, and it was characterized by MDR in 98.36% of the strains. Conclusion: The study revealed a 3-fold increase in the incidence of AB strain infections, significant increase in the resistance to carbapenems in the observed period, and a very high MDR. The solution to this problem would be the implementation of a repair program aiming at inhibition of AB strain transmission, measures to prevent infections, and restricted use of antibiotics.