title: Seasonal Variation of Escherichia coli, Staphylococcus aureus, and Streptococcus pneumoniae Bacteremia According to Acquisition and Patient Characteristics: A Population-Based Study.
abstract: OBJECTIVE Seasonal variation is a characteristic of many infectious diseases, but relatively little is known about determinants thereof. We studied the impact of place of acquisition and patient characteristics on seasonal variation of bacteremia caused by the 3 most common pathogens. DESIGN Seasonal variation analysis. METHODS In 3 Danish health regions (2.3 million total inhabitants), patients with bacteremia were identified from 2000 through 2011 using information from laboratory information systems. Analyses were confined to Escherichia coli, Staphylococcus aureus, and Streptococcus pneumoniae. Additional data were obtained from the Danish National Hospital Registry for the construction of admission histories and calculation of the Charlson comorbidity index (CCI). Bacteremias were categorized as community acquired, healthcare associated (HCA), and hospital acquired. We defined multiple subgroups by combining the following characteristics: species, acquisition, age group, gender, CCI level, and location of infection. Assuming a sinusoidal model, seasonal variation was assessed by the peak-to-trough (PTT) ratio with a 95% confidence interval (CI). RESULTS In total, we included 16,006 E. coli, 6,924 S. aureus, and 4,884 S. pneumoniae bacteremia cases. For E. coli, the seasonal variation was highest for community-acquired cases (PTT ratio, 1.24; 95% CI, 1.17-1.32), was diminished for HCA (PTT ratio, 1.14; 95% CI, 1.04-1.25), and was missing for hospital-acquired cases. No seasonal variation was observed for S. aureus. S. pneumoniae showed high seasonal variation, which did not differ according to acquisition (overall PTT ratio, 3.42; 95% CI, 3.10-3.83). CONCLUSIONS Seasonal variation was mainly related to the species although the place of acquisition was important for E. coli. Infect Control Hosp Epidemiol 2016;37:946-953.
authors.affiliation: Center for Clinical Epidemiology, South, Odense University Hospital, and Research Unit of Clinical Epidemiology, Institute of Clinical Research, University of Southern Denmark, Odense, Denmark.
authors.forename: Kim Oren
authors.initials: KO
authors.lastname: Gradel
authors.affiliation: Department of Infectious Diseases, Odense University Hospital, Odense, Denmark.
authors.forename: Stig Lønberg
authors.initials: SL
authors.lastname: Nielsen
authors.affiliation: Department of Infectious Diseases, Odense University Hospital, Odense, Denmark.
authors.forename: Court
authors.initials: C
authors.lastname: Pedersen
authors.affiliation: Department of Clinical Microbiology, Copenhagen University Hospital, Hvidovre Hospital, Hvidovre, Denmark.
authors.forename: Jenny Dahl
authors.initials: JD
authors.lastname: Knudsen
authors.affiliation: Department of Clinical Microbiology, Copenhagen University Hospital, Hvidovre Hospital, Hvidovre, Denmark.
authors.forename: Christian
authors.initials: C
authors.lastname: Østergaard
authors.affiliation: Department of Clinical Microbiology, Copenhagen University Hospital, Herlev Hospital, Herlev, Denmark.
authors.forename: Magnus
authors.initials: M
authors.lastname: Arpi
authors.affiliation: Department of Clinical Microbiology, Odense University Hospital, Odense, Denmark.
authors.forename: Thøger Gorm
authors.initials: TG
authors.lastname: Jensen
authors.affiliation: Department of Clinical Microbiology, Odense University Hospital, Odense, Denmark.
authors.forename: Hans Jørn
authors.initials: HJ
authors.lastname: Kolmos
authors.affiliation: Department of Clinical Epidemiology, Institute of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Mette
authors.initials: M
authors.lastname: Søgaard
authors.affiliation: Department of Emergency Medicine, Odense University Hospital, Odense, Denmark.
authors.forename: Annmarie Touborg
authors.initials: AT
authors.lastname: Lassen
authors.affiliation: Department of Clinical Microbiology, Aalborg University Hospital, Aalborg, Denmark.|Department of Clinical Medicine, Aalborg University, AalborgDenmark.
authors.forename: Henrik Carl
authors.initials: HC
authors.lastname: Schønheyder
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D003428:Cross Infection / Q000453:epidemiology*; D003718:Denmark / Q000453:epidemiology; D004926:Escherichia coli / Q000302:isolation & purification*; D005260:Female; D006760:Hospitalization; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D012042:Registries; D012621:Seasons; D013203:Staphylococcal Infections / Q000453:epidemiology*; D013211:Staphylococcus aureus / Q000302:isolation & purification*; D013290:Streptococcal Infections / Q000453:epidemiology*; D013296:Streptococcus pneumoniae / Q000302:isolation & purification*; D055815:Young Adult