Enterococci are an increasingly common cause of urinary tract infections (UTI) and asymptomatic bacteriuria (ABU) in hospitalized patients. Despite the publication of guidelines for appropriate antibiotic use, many patients are inappropriately prescribed antimicrobials for ABU. In this month’s issue of Archives of Internal Medicine, Lin et al conducted a retrospective medical record review from two academic teaching hospitals. The authors sought to describe clinical outcomes when Enterococcus was found in the urine, and to investigate the incidence of inappropriate treatment for enterococcal ABU.

Diagnostic criteria for UTI or ABU were classified according to Infectious Diseases Society of America guidelines; the unit of analysis was an episode of bacteriuria. The analysis included 339 episodes of enterococcal bacteriuria, of which 183 cases (54%) were ABU and 156 (46%) were UTI. Patients with UTI were statistically significantly more likely to have higher bacterial counts, pyuria, hematuria, presence of an indwelling catheter, and neutropenia. Sixty of the 183 patients with ABU (32.8%) were inappropriately given antibiotics. Twenty-three of 156 patients with UTI (14.7%) were inappropriately undertreated (no antibiotics given). The most commonly used antimicrobials were quinolones (more than 50% for both UTI and ABU). The consequences of under- or over-treatment were not described in terms of patient outcomes, although a summary of distant infectious complications due to enterococcus within 30 days of bacteriuria was provided.

There appears to be much room for improvement in terms of better antibiotic stewardship with hospitalized patients. In previous studies, up to 50% of antimicrobial use is believed to be inappropriate. (1,2) In this study, a significant number of patients were both under- and over-treated. Moreover, the class of antibiotics most commonly prescribed — quinolones — is known to have limited activity against enterococci. Misclassification bias and reviewer bias were two potential limitations in this retrospective study. Moreover, co-infection with other bacteria may have partially confounded the results. Both the authors and the invited commentators conclude that, due to the rarity of infectious complications associated with Enterococcus, ABU ought not to be treated.

The results from this study support current efforts to curtail inappropriate antimicrobial use through stewardship programs, focused antimicrobial use campaigns, and mindful practice.

1. Davey P, et al. Interventions to improve antibiotic prescribing practices for hospital inpatients. Cochrane Database Syst Rev2005; (4): CD003543.

2. Flanders SA & Saint S. Enhancing the safety of hospitalized patients: Who is minding the antimicrobials? Arch Intern Med 2012; 172(1): 38-40.

Concise Critical Appraisal is a regular feature authored by SCCM member Samuel M. Galvagno Jr., DO. Each installment highlights journal articles most relevant to the critical care practitioner.