Direct E-test on lower respiratory tract samples: improving antimicrobial use in ventilator-associated pneumonia

Abstract number: p1436

Bouza  E., Torres  M.V., Radice  C., Cercenado  E., Muñoz  P., Diego  R., Sanchez  C.


Rapid microbiological assessment of Ventilator-Associated Pneumonia (VAP) can reduce morbidity and mortality. Conventional isolation, identification and susceptibility of bacteria can take no less than 48–72 hours for a final report. Direct E-Test on Lower Respiratory Tract Samples (eT-LRT) samples correlates well with conventional antimicrobial susceptibility tests (Cercenado E, et al. ABSTRACT 42nd ICAAC).


We prospectively assessed the impact of providing direct eT-LRT to clinicians in our institution in patients with clinical suspicion of VAP.


From December 2003 to June 2005, patients with suspicion of VAP and a positive direct Gram stain on LRT samples were randomised in two groups (2:1) for two different laboratory routines. Routine A included a direct eT-LRT antibiogram performed with 6 antibiotic strips (oxacillin, ciprofloxacin, amikacin, cefepime, imipenem and piperacillin-tazobactam). Results of this "preliminary" eT-LRT were sent to the attending physician a mean of 1.4 days afterwards with no further intervention followed by the traditional routine report. Routine B included only traditional routine identification and antibiogram when susceptibility test results were available. We measured the impact of Routine A and B in the management of antimicrobial agents and in the clinical evolution of both groups.


Overall, 231 patients with confirmed VAP were included in the study (157 routine A and 74 routine B). Both populations had similar basal epidemiological and clinical characteristics. The comparison between Routine A and Routine B was as follows: days of fever (4.5 ± 5 vs. 8 ± 6; P < 0.01); DDDs of antibiotics (31 ± 24 vs. 43 ± 33; P < 0.01) days of antimicrobial therapy (15 ± 9 vs. 19 ± 10; P: 0.03); percentage of DDDs considered adequate (91% vs. 65%, P < 0.01); proportion of days on adequate therapy (95% vs. 74%, P < 0.01); C. difficile-associated diarrhoea (1.9% vs. 10.8%; P < 0.01); plain expenses on antimicrobials per episode ([euro]666 vs. 982; P = 0.01). Days on ventilation (18 vs. 19 ns) and ICU stay (24 vs. 27 ns).


A rapid susceptibility test performed directly on LRT secretions by 6 e-test strips significantly improves the accuracy of antimicrobial therapy of patients with VAP and reduces the rates of adverse effects.

Session Details

Date: 01/08/2007
Time: 00:00-00:00
Session name: XXIst ISTH Congress
Location: Oxford, UK
Presentation type:
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