Non-elective and revision arthroplasty are independently associated with hip and knee prosthetic joint infection caused by Acinetobacter baumannii: a Brazilian single center observational cohort study of 98 patients

BackgroundProsthetic joint infection (PJI) caused by Acinetobacter baumannii (Ab) has become a growing concern due to its overwhelming ability to express resistance to antibiotics and produce biofilm.AimThis study aimed to identify independent risk factors (RFs) associated with Ab-associated PJI and their role in the treatment outcome.MethodsThis was a single-centre, retrospective cohort study of PJI patients diagnosed between January 2014 and July 2018. A PJI diagnosis was made based upon the MSIS 2018 criteria. To estimate RFs associated with Ab-associated PJI, multivariate analyses with a level of significance of p<0.05 were performed. To evaluate treatment failure, Kaplan-Meier analysis and log-rank test were performed.ResultsOverall, 98 PJI cases were assessed, including 33 with Ab-associated PJI and 65 with PJI involving other microorganisms (non-Ab-associated PJI). Independent RFs associated with Ab-associated PJI were revision arthroplasty [odds ratio (OR)=3.01; 95% confidence interval (CI)=1.15-7.90; p=0.025] and nonelective arthroplasty (OR=2.65; 95% CI=1.01-7.01; p=0.049). Ab-associated PJI was also more likely than non-Ab-associated PJI to be classified as a chronic late infection (OR=5.81; 95% CI=2.1-16.07; p=0.001). Ab-associated PJI was not associated with treatment failure (p=0.557).ConclusionsLate chronic infections, surgical revision and nonelective arthroplasty are well-known predictors of PJI but were also independently associated with Ab-associated PJI. Infections caused by Ab and surgical treatment with debridement, antibiotics and implant retention were not associated with PJI treatment failure.Trial registrationStudy data supporting our results were registered with the Brazilian Registry of Clinical Trials (https://www.ensaiosclinicos.gov.br/rg/RBR-6ft5yb/), an open-access virtual platform for the registration of studies on humans performed in Brazil.Registration no.RBR-6ft5yb.