Antibiotic consumption versus the prevalence of multidrug-resistant Acinetobacter baumannii and Clostridium difficile infections at an ICU from 2014-2015

Background: Acinetobacter baumannii strains are currently the most commonly isolated non-fermenting rods at Polish intensive care units (ICUs), and they are the dominant aetiological agents of pneumonia. This study aimed to evaluate the prevalence of A. baumannii isolated from patients who were hospitalised at Sosnowiec Hospital's ICU. We also investigated the drug sensitivity of A. baumannii in relation to antibiotic consumption expressed as the defined daily dose (DDD) and Clostridium difficile infection (CDI).

Methods: We performed a retrospective, laboratory-based study, which comprised consecutive, non-repetitive A. baumannii isolates from bloodstream infections and patients with pneumonia who were hospitalised from 2014-2015.

Results: In the analysed period, 187 A. baumannii strains constituted 13.5% of all pathogens from clinical samples. A total of 76.5% of these strains were extensively drug resistant. Resistance of A. baumannii to fluoroquinolones, amikacin, and trimethoprim/sulfamethoxazole exceeded 90%. A total of 95% of strains were resistant to imipenem and meropenem, and 100% were resistant to cephalosporins and tetracyclines. Antibiotic consumption was 191.54 DDD for 100 patient-days, and the highest use of antibiotics involved ampicillin with sulbactam. The cumulative CDI incidence rate was 2.4%.

Conclusions: In our ICU, all of the strains were extensively drug resistant and sensitive to colistin. The significantly high consumption of carbapenems, fluoroquinolones, and aminoglycosides should be reduced because the high CDI incidence is probably related to extensive antibiotic consumption.