Is a strategy based on routine endotracheal cultures the best way to prescribe antibiotics in ventilator-associated pneumonia?
OBJECTIVE
The objectives of this study were to evaluate if a strategy based on routine endotracheal aspirate (ETA) cultures is better than using the American Thoracic Society/Infectious Diseases Society of America (ATS/IDSA) guidelines to prescribe antimicrobials in ventilator-associated pneumonia (VAP).


METHODS
This was a prospective, observational, cohort study conducted in a 15-bed ICU and comprising 283 patients who were mechanically ventilated for ≥48 h. Interventions included twice-weekly ETA; BAL culture was done if VAP was suspected. BAL (collected at the time of VAP) plus ETA cultures (collected≤7 days before VAP) (n=146 different pairs) were defined. We compared two models of 10 days of empirical antimicrobials (ETA-based vs ATS/IDSA guidelines-based strategies), analyzing their impact on appropriateness of therapy and total antimicrobial-days, using the BAL result as the standard for comparison.


RESULTS
Complete ETA and BAL culture concordance (identical pathogens or negative result) occurred in 52 pairs; discordance (false positive or false negative) in 67, and partial concordance in two. ETA predicted the etiology in 62.4% of all pairs, in 74.0% of pairs if ETA was performed≤2 days before BAL, and in 46.2% of pairs if ETA was performed 3 to 7 days before BAL (P=.016). Strategies based on the ATS/IDSA guidelines and on ETA results led to appropriate therapy in 97.9% and 77.4% of pairs, respectively (P<.001). The numbers of antimicrobial-days were 1,942 and 1,557 for therapies based on ATS/IDSA guidelines and ETA results, respectively (P<.001).


CONCLUSIONS
The ATS/IDSA guidelines-based approach was more accurate than the ETA-based strategy for prescribing appropriate, initial, empirical antibiotics in VAP, unless a sample was available≤2 days of the onset of VAP. The ETA-based strategy led to fewer days on prescribed antimicrobials.
Pulmonary and Critical Medicine Divisions, Universidad de Buenos Aires, Argentina. Electronic address: dr.cm.luna@gmail.com.
Carlos M
CM
Luna
Pulmonary and Critical Medicine Divisions, Universidad de Buenos Aires, Argentina.
Sergio
S
Sarquis
Department of Medicine, Winthrop University Hospital, Mineola, NY; Department of Clinical Biochemistry, Facultad de Farmacia y Bioquímica, Hospital de Clínicas, Universidad de Buenos Aires, Argentina.
Michael S
MS
Niederman
Pulmonary and Critical Medicine Divisions, Universidad de Buenos Aires, Argentina.
Fernando A
FA
Sosa
Pulmonary and Critical Medicine Divisions, Universidad de Buenos Aires, Argentina.
Maria
M
Otaola
Pulmonary and Critical Medicine Divisions, Universidad de Buenos Aires, Argentina.
Nicolas
N
Bailleau
Department of Medicine, and Microbiology Section, Universidad de Buenos Aires, Argentina.
Carlos A
CA
Vay
Department of Medicine, and Microbiology Section, Universidad de Buenos Aires, Argentina.
Angela
A
Famiglietti
Pulmonary and Critical Medicine Divisions, Universidad de Buenos Aires, Argentina.
Célica
C
Irrazabal
Pulmonary and Critical Medicine Divisions, Universidad de Buenos Aires, Argentina.
Abelardo A
AA
Capdevila
D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D001707:Biopsy, Needle; D018893:Bronchoalveolar Lavage; D015331:Cohort Studies; D046508:Culture Techniques / Q000379:methods*; D003955:Diagnostic Tests, Routine / Q000379:methods*; D005260:Female; D006801:Humans; D007362:Intensive Care Units; D008297:Male; D008875:Middle Aged; D053717:Pneumonia, Ventilator-Associated / Q000175:diagnosis* / Q000188:drug therapy* / Q000401:mortality; D017410:Practice Guidelines as Topic; D011446:Prospective Studies; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D015996:Survival Rate; D014132:Trachea / Q000382:microbiology* / Q000473:pathology; D016896:Treatment Outcome
D000900:Anti-Bacterial Agents