A global threat: Acinetobacter baumannii infections, current condition in antimicrobial resistance and alternative treatment approaches [Küresel bir tehdit: Acinetobacter baumannii enfeksiyonlari, antimikrobiyal dirençte güncel durum ve alternatif tedavi yaklaşimlari]

Acinetobacter baumannii is an important nosocomial pathogens that cause serious infections such as ventilator-associated pneumonia, catheter-related bacteriemia, urinary tract infections, soft tissue infections, septicemia and meningitis. Various virulence factors such as polysaccharide capsule, fimbria, lipid A and lipopolysaccharide structure, siderophore, secretion systems, biofilm formation and antibiotic resistance genes contribute to the pathogenesis of the bacteria. Carbapenems, aminoglycosides, sulbactam, colistin and tigecycline are frequently used antimicrobial agents in Acinetobacter infections. Resistance to carbapenems is usually seen as multidrug resistance (MDR). As reported from various centers, the development of resistance to tigecycline and colistin, used in the treatment of MDR isolates, makes treatment of A. baumannii infections more difficult. In 2018, the World Health Organization published 'global priority list of antibiotic-resistant bacteria requiring new antibiotic discovery' and A. baumannii has been at the top of this list. The alarming dimension of the antimicrobial resistance in A. baumannii was clearly demonstrated by this report. Understanding of the virulence and resistance mechanisms of the bacterium is essential for effective treatment and fighting antibiotic resistance. In combating MDR bacteria that have become a global health problem such as A. baumannii, infection control preventions, rational antibiotic use and anti-virulence strategies need to be used in a holistic approach. The studies carried on alternative therapies such as combined antibiotic use, efflux pump inhibitors, anti-biofilm agents and phage therapy are of great importance. In this review; the current knowledge about the factors involved in pathogenesis of A. baumannii, its epidemiological characteristics, antibiotic resistance mechanisms and alternative treatment approaches for combating had been evaluated. © 2020 Refik Saydam National Public Health Agency (RSNPHA)