Impact of carbapenem resistance on epidemiology and outcomes of nonbacteremic Klebsiella pneumoniae infections

Abstract

Background: Although high mortality associated with carbapenem-resistant Klebsiella pneumoniae (CRKP) bacteremia has been well described, the epidemiology and outcomes of nonbacteremic infection are unknown.

Methods: Medical charts of adults hospitalized for CRKP pneumonia or urinary tract infection between January 2011 and December 2013 were reviewed retrospectively for relevant demographic and clinical details. Cases were matched to controls (non-carbapenem-resistant, non-extended-spectrum beta-lactamase [ESBL]-producing K pneumoniae [NRKP]) by the primary site of infection and year of isolation and compared in terms of risk of acquisition and outcomes.

Results: The CRKP and NRKP arms (n = 48 each) were elderly (median age, 74 years). Compared with controls, more patients in the CRKP arm resided in skilled nursing/long-term acute care facilities (77% vs 29%; P < .01), had a chronic tracheostomy (29% vs 0%; P < .001), decubitus ulcers (69% vs 17%; P < .01), higher Acute Physiology and Chronic Health Evaluation (APACHE) II scores (median, 21.5 vs 14; P = .02), and required intensive care unit admission (54% vs 31%; P = .04). More patients in the CRKP arm had previous ESBL infection (23% vs 6%; P = .04), and this arm had at least a 10-fold greater risk of coinfection with other carbapenem-resistant pathogens (44% vs 4%; P < .01), as well as a 7-fold greater likelihood of previous carbapenem therapy (23% vs 4%; P = .01). Patients in the CRKP arm had prolonged hospitalization (median, 13 days) and a 32% rate of readmission within 30 days of discharge.

Conclusions: CRKP nonbacteremic infections occur in debilitated patients and are associated with frequent previous carbapenem exposure and high resource utilization, underscoring the need to focus efforts on antimicrobial stewardship and infection control.

Keywords: Carbapenem-resistant Klebsiella pneumoniae; Nonbacteremia.