Recurrent Pseudomonas aeruginosa Bacteremia
Authors: Ek Juliann , Tatineni Vineeth , Myers David , Myers Joseph 
Published: December 2020

Introduction
As part of an institutional review board–approved quality improvement project reviewing 10 years of experience (2009–2018) with Pseudomonas aeruginosa bacteremia (PAB) at our institution, we identified 15 patients with recurrent Pseudomonas bacteremia. Because recurrent P. aeruginosa bacteremia (RPAB) is uncommon, we reviewed our patients with PAB to evaluate its occurrence, epidemiology, clinical characteristics, and outcomes of care.

Methods
This was an institutional review board–approved quality improvement project. We reviewed the medical records of all patients with PAB from January 1, 2009, to December 31, 2018, and identified the subset of patients with RPAB. We report the incidence, epidemiology, source of bacteremia, comorbid conditions, treatment, and outcome for patients with RPAB. We compare these data to previously published series of PAB patients with RPAB.

Results
We identified 268 episodes of PAB. One patient with 6 occurrences of PAB secondary to injection drug use–associated tricuspid valve endocarditis was excluded because of noncompliance with therapy. This left 262 episodes of PAB for evaluation. Fifteen patients had a total of 19 episodes of RPAB: 13 patients had 2 episodes (1 recurrence each), 1 patient had 3 episodes (2 recurrences), and 1 patient had 5 episodes (4 recurrences). The recurrence rate was 7.3% (19/262). The mean and median ages for patients with RPAB were 59 and 58 years, respectively. The time between episodes of PAB ranged from 26 to 688 days with a mean and median of 166 and 97 days, respectively. There were 3 patients (16%) with different sources of bacteremia for consecutive episodes of PAB: 1 with neutropenic sepsis followed by acute mastoiditis, 1 with cellulitis of the leg followed by an infected sacral pressure ulcer, and 1 with pneumonia and then an infected arteriovenous graft. The source of the recurrent episode was the same as the prior episode in 16 instances (84%): (1) skin and soft tissue infection (7 episodes), (2) central venous catheter infection (3 episodes), (3) genitourinary infection (2 episodes), (4) pneumonia (1 episode), (5) infected aortic vascular graft (1 episode), (6) obstructive cholangitis (1 episode), and (7) primary bacteremia (1 episode). All but 2 patients had multiple comorbid conditions, and all but 1 patient with RPAB had ≥1 of 5 risk factors for PAB as reported in the literature. Six (32%) of 19 episodes of RPAB resulted in death. Five of 6 patients with fatal RPAB received appropriate antimicrobial therapy at the initial presentation to the hospital for the second/fatal episode. Infectious disease consultation was obtained in all but 1 episode of RPAB.

Conclusions
Recurrent PAB accounted for 19 (7.3%) of 262 episodes of PAB in our 10-year study. It was associated with multiple comorbid conditions. The recurrent episode was usually from the same source as the prior episode of PAB. Sources of RPAB were diverse (as discussed previously), and mortality was 32% despite appropriate antipseudomonal antimicrobial therapy in all but 1 episode of those who died. We review the literature for patients with RPAB and compare these patients with those in our patient population.