Current Spectrum of Causative Pathogens in Sepsis: A Prospective Nationwide Cohort Study in Japan

Abstract Background There is no one-size-fits-all empiric antimicrobial therapy for sepsis because the pathogens vary according to the site of infection and have changed over time. Therefore, updating the knowledge on the spectrum of pathogens is necessary for rapid administration of appropriate antimicrobials. Objective To elucidate the current spectrum of pathogens and its variation by site of infection in sepsis. Methods We used a prospective nationwide cohort comprising consecutive adult patients with sepsis in 59 intensive care units in Japan and evaluated the spectrum of pathogens in all patients and in subgroups by site of infection. We also conducted regression analyses to evaluate the association between the pathogens and mortality. Results The study cohort comprised 1184 patients. The most common pathogen was Escherichia coli (21.5%), followed by Klebsiella pneumoniae (9.0%); however, these patterns varied widely by the site of infection. For example, Gram-positive bacteria were the dominant pathogen in bone/soft tissue (55.7%) and cardiovascular infection (52.6%) but were rarely identified in urinary tract infection (6.4%). In contrast, Gram-negative bacteria were in the majority in abdominal infection (38.4%) and urinary tract infection (72.0%). The highest mortality of 47.5% was observed in patients infected with methicillin-resistant S. aureus, which was significantly associated with an increased risk of death (odds ratio 1.88; 95% confidence interval 1.22–2.91). Conclusions The present study revealed the current spectrum of pathogens and its variation based on the site of infection, which is essential for empiric antimicrobial therapy against sepsis.