Low incidence of antibiotic-resistant bacteria in south-east Sweden: An epidemiologic study on 9268 cases of bloodstream infection

• Published in: PloS one Vol. 15; no. 3; p. e0230501
• Main Authors: Holmbom, Martin, Möller, Vidar, Nilsson, Lennart E, Giske, Christian G, Rashid, Mamun-Ur, Fredrikson, Mats, Hällgren, Anita, Hanberger, Håkan, Balkhed, Åse Östholm
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 27-03-2020; Public Library of Science (PLoS)
• Subjects: Analysis; Antibacterial agents; Antibiotic resistance; Antibiotics; Antiinfectives and antibacterials; Antimicrobial agents; Bacteremia; Bacteria; Beta lactamases; Biology and Life Sciences; Comorbidity; Drug dosages; Drug resistance; E coli; Electronic records; Epidemiology; Escherichia coli; Folkhälsovetenskap, global hälsa, socialmedicin och epidemiologi; Gender; Health aspects; Health risks; Health sciences; Hospital admission and discharge; Hospital patients; Hospitals; Hälsovetenskap; Infection; Infections; Infectious diseases; Infektionsmedicin; Klebsiella; Klinisk medicin; Laboratories; Medical research; Medicin och hälsovetenskap; Medicine; Medicine and Health Sciences; Medicinska och farmaceutiska grundvetenskaper; Methicillin; Microbial drug resistance; Microbiology; Microorganisms; Mikrobiologi inom det medicinska området; Mortality; Mortality risk; Multidrug resistance; Pathogens; People and places; Pneumonia; Population; Public health; Risk analysis; Risk factors; Sepsis; Setting (Literature); Staphylococcus aureus; Staphylococcus aureus infections; Staphylococcus infections; Statistical analysis; Streptococcus infections; Streptococcus pneumoniae; Sweden; Vancomycin; Sweden
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0230501

The aim of this study was to investigate the epidemiology of bloodstream infections (BSI) in a Swedish setting, with focus on risk factors for BSI-associated mortality.
A 9-year (2008-2016) retrospective cohort study from electronic records of episodes of bacteremia amongst hospitalized patients in the county of Östergötland, Sweden was conducted. Data on episodes of BSI including microorganisms, antibiotic susceptibility, gender, age, hospital admissions, comorbidity, mortality and aggregated antimicrobial consumption (DDD /1,000 inhabitants/day) were collected and analyzed. Multidrug resistance (MDR) was defined as resistance to at least three groups of antibiotics. MDR bacteria and MRSA, ESBL-producing Enterobacteriaceae, vancomycin-resistant enterococci not fulfilling the MDR criteria were all defined as antimicrobial-resistant (AMR) bacteria and included in the statistical analysis of risk factors for mortality.
In all, 9,268 cases of BSI were found. The overall 30-day all-cause mortality in the group of patients with BSI was 13%. The incidence of BSI and associated 30-day all-cause mortality per 100,000 hospital admissions increased by 66% and 17% respectively during the nine-year study period. The most common species were Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, Streptococcus pneumoniae and Enterococcus faecalis. Independent risk factors for 30-day mortality were age (RR: 1.02 (CI: 1.02-1.03)) and 1, 2 or ≥3 comorbidities RR: 2.06 (CI: 1.68-2.52), 2.79 (CI: 2.27-3.42) and 2.82 (CI: 2.31-3.45) respectively. Almost 3% (n = 245) of all BSIs were caused by AMR bacteria increasing from 12 to 47 per 100,000 hospital admissions 2008-2016 (p = 0.01), but this was not associated with a corresponding increase in mortality risk (RR: 0.89 (CI: 0.81-0.97)).
Comorbidity was the predominant risk factor for 30-day all-cause mortality associated with BSI in this study. The burden of AMR was low and not associated with increased mortality. Patients with BSIs caused by AMR bacteria (MDR, MRSA, ESBL and VRE) were younger, had fewer comorbidities, and the 30-day all-cause mortality was lower in this group.