Cytokine responses to Staphylococcus aureus bloodstream infection differ between patient cohorts that have different clinical courses of infection.
BACKGROUND
The clinical course of Staphylococcus aureus bloodstream infection is unpredictable and bacterial virulence, host immune response and patient characteristics are among the factors that contribute to the clinical course of infection. To investigate the relationship between cytokine response and clinical outcome, circulating cytokine levels were investigated in response to S. aureus bloodstream infection in patients with different clinical courses of infection.


METHODS
A prospective study was carried out in 61 patients with S. aureus bloodstream infection and circulating levels of IL-6, GRO-γ, RANTES and leptin were assessed over the course of the infection. Levels were compared in patients with complicated courses of infection (e.g. infective endocarditis) versus uncomplicated courses of S. aureus bloodstream infection and methicillin-resistant S. aureus Vs methicillin-susceptible S. aureus infection.


RESULTS
Significantly lower leptin levels (p < 0.05) and significantly higher IL-6 levels (p < 0.05) were detected at laboratory diagnosis in patients with complicated compared to uncomplicated S. aureus bloodstream infection. Significantly higher levels of GRO-γ were associated with MRSA infection compared to MSSA infection.


CONCLUSIONS
IL-6 may be an early inflammatory marker of complicated S. aureus bloodstream infection. Leptin may be protective against the development of a complicated S. aureus bloodstream infection.
Sinead
S
McNicholas
Alida Fe
AF
Talento
Joanne
J
O'Gorman
Margaret M
MM
Hannan
Maureen
M
Lynch
Catherine M
CM
Greene
Hilary
H
Humphreys
Deirdre
D
Fitzgerald-Hughes
D000368:Aged; D016470:Bacteremia / Q000097:blood / Q000150:complications / Q000382:microbiology*; D015415:Biomarkers / Q000097:blood; D016207:Cytokines / Q000097:blood*; D004697:Endocarditis, Bacterial / Q000097:blood / Q000150:complications; D005260:Female; D006801:Humans; D008297:Male; D055624:Methicillin-Resistant Staphylococcus aureus / Q000302:isolation & purification / Q000472:pathogenicity*; D008875:Middle Aged; D011446:Prospective Studies; D013203:Staphylococcal Infections / Q000097:blood / Q000382:microbiology*; D013211:Staphylococcus aureus / Q000302:isolation & purification / Q000472:pathogenicity*
D015415:Biomarkers; D016207:Cytokines