Blood neutrophil bactericidal activity against methicillin-resistant and methicillin-sensitive Staphylococcus aureus during cardiac surgery.
Whether methicillin-resistant Staphylococcus aureus (MRSA) constitutes per se an independent risk factor for morbidity and mortality after surgery as compared with methicillin-sensitive Staphylococcus aureus (MSSA) remains a subject of debate. The aim of this study was to assess whether innate defenses against MRSA and MSSA strains are similarly impaired after cardiac surgery. Both intracellular (isolated neutrophil functions) and extracellular (plasma) defenses of 12 patients undergoing scheduled cardiac surgery were evaluated preoperatively (day 0) and postoperatively (day 3) against two MSSA strains with a low level of catalase secretion and two MRSA strains with a high level of catalase secretion, inasmuch as SA killing by neutrophils relies on oxygen-dependent mechanisms. After surgery, an increase in plasma concentration of IL-10, an anti-inflammatory cytokine able to inhibit reactive oxygen species secretion and bactericidal activity of neutrophils, was evidenced. Despite the fact that univariate analysis suggested a specific impairment of neutrophil functions against MRSA strains, two-way repeated-measures ANOVA failed to demonstrate that the effect of S. aureus phenotype was significant. On the other hand, an increase in type-II secretory phospholipase A2 activity, a circulating enzyme involved in SA lysis, was evidenced and was associated with an enhancement of extracellular defenses (bactericidal activity of plasma) against MRSA. Overall, cardiac surgery and S. aureus phenotype had a significant effect on plasma bactericidal activity. Cardiac surgery was characterized by enhanced antibacterial defenses of plasma, whereas neutrophil killing properties were reduced. The overall effect of S. aureus phenotype on neutrophil functions did not seem significant.
Mekontso-Dessap
Armand
A
Unité INSERM U.492, Faculté de Médecine de Créteil-Université Paris XII, Paris, France. armand.dessap@creteil.inserm.fr
Honoré
Stéphanie
S
Kirsch
Matthias
M
Plonquet
Anne
A
Fernandez
Eric
E
Touqui
Lhousseine
L
Farcet
Jean-Pierre
JP
Soussy
Claude-James
CJ
Loisance
Daniel
D
Delclaux
Christophe
C
D000368:Aged; D000704:Analysis of Variance; D000890:Anti-Infective Agents / Q000494:pharmacology*; D001770:Blood Bactericidal Activity / Q000187:drug effects*; D002315:Cardiopulmonary Bypass / Q000379:methods*; D002374:Catalase / Q000378:metabolism; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D016753:Interleukin-10 / Q000097:blood / Q000378:metabolism; D008297:Male; D008712:Methicillin / Q000494:pharmacology*; D016106:Methicillin Resistance; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D009504:Neutrophils / Q000187:drug effects* / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism; D010587:Phagocytosis; D010641:Phenotype; D017382:Reactive Oxygen Species; D013203:Staphylococcal Infections / Q000188:drug therapy* / Q000517:prevention & control*; D013211:Staphylococcus aureus / Q000378:metabolism*; D013997:Time Factors
D000890:Anti-Infective Agents; D017382:Reactive Oxygen Species; D016753:Interleukin-10; D006861:Hydrogen Peroxide; D002374:Catalase; D008712:Methicillin; D010100:Oxygen