Bloodstream infections in adults: Importance of healthcare-associated infections
Introduction
Bloodstream infection (BSI) continues to be an important cause of morbidity and mortality, despite the availability of potent antimicrobial agents and sophisticated life-support facilities. In recent years, studies of epidemiology, microbiological etiology, and prognosis have been performed all over the world.1, 2, 3, 4, 5, 6, 7, 8
BSI has traditionally been categorized as community and hospital-acquired infections.9, 10 A hospital-acquired infection is typically acquired in an environment of resistant microorganisms or microorganisms typically found in a hospital setting and it is often associated with a procedure or with instrumentation. A community-acquired infection presumably develops spontaneously, without an association with a medical intervention and occurs in an environment with fewer resistance pressures. However, some infections are acquired under circumstances that do not readily allow for the infection to be classified, as belonging to either of these two categories. Such infections include infections in patients with serious underlying diseases and/or invasive devices receiving care at home or in nursing homes or rehabilitation centers; those undergoing dialysis or chemotherapy in physicians’ offices and those who frequently have contact with healthcare or recurrent hospital admissions. For this reason, a new classification scheme for BSIs has been proposed to characterize these difficult-to-classify BSIs and distinguish between infections occurring among outpatients having recurrent or recent contact with the healthcare system, patients with true community-acquired infections and the inpatients with hospital-acquired infections. The preliminary results have demonstrated that healthcare-associated infections are similar to hospital-acquired infections and consequently the empirical antimicrobial therapy should be different from that in community-acquired infections.11, 12
The objective of this study was to evaluate the usefulness of this new classification to analyze the BSI detected in three hospitals in the same geographic area and to compare the three different categories in terms of comorbid conditions, source of infection, pathogens and their antimicrobial susceptibility patterns, appropriateness of antibiotic therapy and prognosis.
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Setting
This prospective, observational, and multicenter study was performed in three hospitals in Catalonia, Spain: Hospital Sabadell (HS), Hospital Mutua Terrassa (HMT), and Hospital Terrassa (HT). All institutions are urban teaching hospitals with intensive care units (ICU) but without any solid organ transplant programs.
Study design
All consecutive adults patients (>18 years) admitted from March 15, 2003 to March 15, 2004, who presented at least one true positive blood culture on admission or developed BSI
Population characteristics
During the study period, a total of 1202 positive blood cultures were detected at the three study hospitals. Of the 1202 cultures, 1157 cultures were considered true BSI; 45 positive blood cultures were excluded from analysis because the patients were transferred to another hospital (n: 31), or because were of unknown clinical significance (n = 14). The 1157 episodes of BSI occurred in 1086 patients, 59 of whom presented more than one episode of bacteremia during the study period.
Of the 1157 BSI,
Discussion
Our results indicate that a quarter of all BSI in our region are healthcare-associated. The characteristics of patients with healthcare-associated BSI in our study show some overlap with community and hospital-acquired BSI. However, differences between community-acquired BSI and healthcare-associated BSI are evident. Healthcare-associated patients are older, have a worse functional status, present a higher proportion of catheter-related BSI and have the highest prevalence of BSI caused by MRSA.
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