Multicenter Study of Clinical Features of Breakthrough Acinetobacter Bacteremia during Carbapenem Therapy

Abstract

Breakthrough bacteremia during carbapenem therapy is not uncommon, and it creates therapeutic dilemmas for clinicians. This study was conducted to evaluate the clinical and microbiological characteristics of breakthrough bacteremia during carbapenem therapy and to assess the efficacy of various antimicrobial therapies. We analyzed 100 adults who developed breakthrough bacteremia during carbapenem therapy at 4 medical centers over a 6-year period. Their 30-day mortality rate was 57.0%, and the carbapenem resistance rate of their isolates was 87.0%. Among patients with carbapenem-resistant bacteremia, breakthrough bacteremia during carbapenem therapy was associated with a significantly higher 14-day mortality (51.7% versus 37.4%, respectively; = 0.025 by bivariate analysis) and a higher 30-day mortality ( = 0.037 by log rank test of survival analysis) than in the nonbreakthrough group. For the treatment of breakthrough bacteremia during carbapenem therapy, tigecycline-based therapy was associated with a significantly higher 30-day mortality (80.0%) than those with continued carbapenem therapy (52.5%) and colistin-based therapy (57.9%) by survival analysis ( = 0.047 and 0.045 by log rank test, respectively). Cox regression controlling for confounders, including severity of illness indices, demonstrated that treatment with tigecycline-based therapy for breakthrough bacteremia was an independent predictor of 30-day mortality (hazard ratio, 3.659; 95% confidence interval, 1.794 to 7.465; < 0.001). Patients with breakthrough bacteremia during carbapenem therapy posed a high mortality rate. Tigecycline should be used cautiously for the treatment of breakthrough bacteremia that develops during carbapenem therapy.

Prospective multi-center evaluation on risk factors, clinical characteristics and outcomes due to carbapenem resistance in Acinetobacter baumannii complex bacteraemia: experience from the Chinese Antimicrobial Resistance Surveillance of Nosocomial Infections (CARES) Network

“…In fact, breakthrough A. baumannii complex bacteremia during carbapenem therapy have been observed [21, 22]. Thus, our findings that prior carbapenems exposure as an independent risk factor for CRAB BSI are consistent with those observations.…”

New Treatment Options against Carbapenem-Resistant Acinetobacter baumannii Infections

“…In addition, its use in VAP was hampered when a phase III RCT showed tigecycline to be inferior to the comparator drug and to have higher mortality rates for VAP patients (17). The results from several recent studies and a meta-analysis are in line with these discouraging results (18)(19)(20), and these combined with increasing rates of tigecycline resistance among CRAB disfavor its use.…”

Current treatment options for pneumonia caused by carbapenem-resistant Acinetobacter baumannii

“…The effectiveness of tigecycline for pneumonia has been called into question by observational and meta-analyses where an increase in mortality has been observed, including in patients with CRAB pneumonia [42][43][44][45]. Although subsequent, nonrandomized studies have suggested that high dose tigecycline may mitigate this effect [46,47], these studies were conducted with combination therapy making it difficult to assess tigecycline monotherapy.…”