Clinical manifestations, antimicrobial therapy, and prognostic factors of monomicrobial Acinetobacter baumannii complex bacteremia

SummaryObjectivesBacteremia due to Acinetobacter baumannii complex (ABC), which composed of four genomic species (gen. sp.), is a serious and potentially fatal condition. The epidemiology and outcome of such infections due to individual gen. sp. remain undefined.MethodsA retrospective study of patients with monomicrobial ABC bacteremia over six years was conducted at a medical center to determine the association of gen. sp. with clinical outcome.ResultsIncluded were 291 patients with monomicrobial ABC bacteremia. Of them, 222 (76.3%) patients had bacteremia caused by gen. sp. 2, i.e. A. baumannii. The presence of multidrug-resistant phenotype was the only independent predictor of Acinetobacter gen. sp. 2 bacteremia (adjusted odd ratio, 7.5; 95% confidence interval, 3.8–14.7; P < 0.001). Patients with Acinetobacter gen. sp. 2 bacteremia had a higher sepsis-related (P = 0.006) and 30 day (P = 0.028) mortality rates than the non-Acinetobacter gen. sp. 2 group. The fatal outcome was independently associated with high SPAS II scores (P = 0.002), rapidly fatal underlying diseases (P = 0.002), bacteremia caused by Acinetobacter gen. sp. 2 (P = 0.01), inappropriate definitive antimicrobial therapy (P < 0.001), and severe sepsis (P < 0.001).ConclusionAcinetobacter gen. sp. 2 bacteremia heralded a worse clinical outcome, and therefore the gen. sp. identification of ABC bacteremic isolates is justified.