title: Resolution of infectious parameters after antimicrobial therapy in patients with ventilator-associated pneumonia.
abstract: Although recommended durations of antimicrobial therapy for ventilator-associated pneumonia (VAP) range from 7 to 21 d, these are not based on prospective studies and little is known about the resolution of symptoms after start of antibiotics. Resolution of these symptoms was investigated in 27 patients. VAP was diagnosed on clinical, radiographic, and microbiological criteria, including quantitative cultures of bronchoalveolar lavage. All patients received appropriate antibiotic therapy. Highest temperatures, leukocyte counts, Pa(O(2))/FI(O(2)) ratios, and semiquantitative cultures of endotracheal aspirates were recorded from start of therapy until Day 14. Resolution was defined as the first day that these parameters fulfilled the following definition: temperature < or = 38 degrees C, leukocytes < or = 10 x 10(9)/L, Pa(O(2))/FI(O(2)) ratio > or = 25 kPa, and no or +1 of bacterial growth of etiologic pathogens in cultures of endotracheal aspirate. VAP was caused by Enterobacteriaceae (n = 14), P. aeruginosa (n = 7), S. aureus (n = 6), H. influenzae (n = 3), and S. pneumoniae (n = 1). H. influenzae and S. pneumoniae were eradicated from tracheal aspirates, whereas Enterobacteriaceae, S. aureus, and P. aeruginosa persisted, despite in vitro susceptibility to antibiotics administered. Significant improvements were observed for all clinical parameters, most apparently within the first 6 d after start of antibiotics. Newly acquired colonization, especially with P. aeruginosa and Enterobacteriaceae, occurred in the second week of therapy. Six patients developed a recurrent episode of VAP, four of them with P. aeruginosa. Clinical responses to therapy for VAP occur within the first 6 d of therapy, endotracheal colonization with Gram-negative bacteria persists despite susceptibility to therapy, and acquired colonization usually occurs in the second week of therapy and frequently precedes a recurrent episode.
authors.affiliation: Department of Medical Microbiology, Medical Technology Assessment and Surgery, University Hospital Maastricht, Maastricht, The Netherlands.
authors.forename: P J
authors.initials: PJ
authors.lastname: Dennesen
authors.forename: A J
authors.initials: AJ
authors.lastname: van der Ven
authors.forename: A G
authors.initials: AG
authors.lastname: Kessels
authors.forename: G
authors.initials: G
authors.lastname: Ramsay
authors.forename: M J
authors.initials: MJ
authors.lastname: Bonten
mesh_terms: D000328:Adult; D000368:Aged; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D001424:Bacterial Infections / Q000097:blood / Q000175:diagnosis* / Q000209:etiology*; D001992:Bronchoalveolar Lavage Fluid / Q000382:microbiology; D003428:Cross Infection / Q000097:blood / Q000175:diagnosis / Q000188:drug therapy* / Q000209:etiology*; D016903:Drug Monitoring; D004756:Enterobacteriaceae Infections / Q000097:blood / Q000175:diagnosis / Q000188:drug therapy / Q000209:etiology; D005260:Female; D006192:Haemophilus Infections / Q000097:blood / Q000175:diagnosis / Q000188:drug therapy / Q000209:etiology; D006193:Haemophilus influenzae; D006801:Humans; D017053:Infection Control / Q000379:methods; D007958:Leukocyte Count; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D011008:Pneumococcal Infections / Q000097:blood / Q000175:diagnosis / Q000188:drug therapy / Q000209:etiology; D011014:Pneumonia / Q000097:blood / Q000175:diagnosis / Q000188:drug therapy* / Q000209:etiology*; D017410:Practice Guidelines as Topic; D016016:Proportional Hazards Models; D011446:Prospective Studies; D011552:Pseudomonas Infections / Q000097:blood / Q000175:diagnosis / Q000188:drug therapy / Q000209:etiology; D012008:Recurrence; D012121:Respiration, Artificial / Q000009:adverse effects*; D012307:Risk Factors; D013203:Staphylococcal Infections / Q000097:blood / Q000175:diagnosis / Q000188:drug therapy / Q000209:etiology; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D000900:Anti-Bacterial Agents