Risk for subsequent infection and mortality after hospitalization among patients with multidrug-resistant gram-negative bacteria colonization or infection

Wen-Pin Tseng,Shang-Yu Chen,Yee-Chun Chen,Shey-Ying Chen,Shan-Chwen Chang

doi:10.1186/s13756-018-0388-z

Abstract

BackgroundRisks for subsequent multidrug-resistant gram-negative bacteria (MDRGNB) infection and long-term outcome after hospitalization among patients with MDRGNB colonization remain unknown.MethodsThis observational study enrolled 817 patients who were hospitalized in the study hospital in 2009. We defined MDRGNB as a GNB resistant to at least three different antimicrobial classes. Patients were classified into MDRGNB culture-positive (MDRGNB-CP; 125 patients) and culture-negative (MDRGNB-CN; 692 patients) groups based on the presence or absence of any MDRGNB identified from either active surveillance or clinical cultures during index hospitalization. Subsequent MDRGNB infection and mortality within 12 months after index hospitalization were recorded. We determined the frequency and risk factors for subsequent MDRGNB infection and mortality associated with previous MDRGNB culture status.ResultsIn total, 129 patients had at least one subsequent MDRGNB infection (MDRGNB-CP, 48.0%; MDRGNB-CN, 10.0%), and 148 patients died (MDRGNB-CP, 31.2%; MDRGNB-CN, 15.9%) during the follow-up period. MDR Escherichia coli and Acinetobacter baumannii were the predominant colonization microorganisms; patients with Proteus mirabilis and Pseudomonas aeruginosa had the highest hazard risk for developing subsequent infection. After controlling for other confounders, MDRGNB-CP during hospitalization independently predicted subsequent MDRGNB infection (hazard ratio [HR], 5.35; 95% confidence interval [CI], 3.72–7.71), all-cause mortality (HR, 2.42; 95% CI, 1.67–3.50), and subsequent MDRGNB infection-associated mortality (HR, 4.88; 95% CI, 2.79–8.52) after hospitalization.ConclusionsHarboring MDRGNB significantly increases patients’ risk for subsequent MDRGNB infection and mortality after hospitalization, justifying the urgent need for developing effective strategies to prevent and eradicate MDRGNB colonization.

Highlights

Risks for subsequent multidrug-resistant gram-negative bacteria (MDRGNB) infection and long-term outcome after hospitalization among patients with MDRGNB colonization remain unknown
MDRGNB-CP patients had a higher percentage of having cardiovascular diseases and a bed-ridden status, presence of a pressure sore or indwelling urinary catheter, receiving intensive care unit (ICU) care and tracheal intubation, and antibiotic exposure during index hospitalization
Analysis for species-specific risk for subsequent infection after index hospitalization discharge showed that the hazard risk in patients with initial MDR Proteus mirabilis culture was higher (HR, 231.29; 95% CI, 32.10–1666.31) than those without any MDRGNB culture, followed by MDR P. aeruginosa (HR, 56.99; 95% CI, 21.53–150.88), MDR E. coli (HR, 36.83; 95% CI, 17.59–77.14), MDR K. pneumoniae (HR, 15.83; 95% CI, 5.17–48.48), and MDR A. baumannii (HR, 15.25; 95% CI, 7.58–30.69)

Summary

Introduction

Risks for subsequent multidrug-resistant gram-negative bacteria (MDRGNB) infection and long-term outcome after hospitalization among patients with MDRGNB colonization remain unknown. The risk for subsequent infection was significantly higher for hospitalized patients with initial antimicrobial-resistant GNB colonization than patients without colonization [8, 13,14,15]. 9.1–39% of inpatients who were initially colonized with various antimicrobial-resistant GNB developed subsequent infection during the same hospital stay [8, 10, 12,13,14]. The effect of initial MDRGNB colonization on the risk for subsequent infection and clinical outcomes among hospitalized patients is well documented, and it significantly influences the recommendations for controlling and treating MDRGNB infections in hospital settings

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