No Benefit From Prophylactic Antimicrobials in Aspiration Pneumonitis

Pneumonia, chest x-ray
Pneumonia, chest x-ray
Use of prophylactic antimicrobial therapy was not associated with a reduction in mortality or transfer to critical care compared with patients managed with supportive care only.

In patients with acute aspiration pneumonitis, antimicrobial therapy within 48 hours of macro-aspiration was not associated with reduced mortality and resulted in more frequent antibiotic escalation and fewer antibiotic-free days, according to a study published in Clinical Infectious Diseases.

A retrospective cohort study was used to assess outcomes in patients receiving antimicrobial prophylaxis or standard supportive care 2 days following an acute aspiration pneumonitis event. The primary outcome was in-hospital mortality within 30-days. Secondary outcomes included transfer to critical care and antimicrobial therapy received, including escalation of therapy and antibiotic-free days between days 3 to 14 following the acute aspiration event.

Of the 200 patients meeting study criteria, 76 (38%) received prophylactic antimicrobial therapy and 124 (62%) received supportive management only. Unadjusted in-hospital mortality in both groups was comparable. Patients receiving antimicrobial prophylaxis were no less likely to require transfer to critical care (5% vs 6%; P =.7) and they received more frequent escalation of antibiotic therapy (8% vs 1%; P =.002) and fewer antibiotic-free days (7.5 vs 10.9; P <.0001). Further, after adjusting for patient-level predictors, antimicrobial prophylaxis was not associated with improvements in mortality (OR 0.9; 95% CI, 0.4-1.7; P =.7).

Several study limitations, such as potential confounding factors and small cohort size were noted by investigators.  Also, the study design did not evaluate the effect of prophylactic antimicrobial therapy on the development of pneumonia; instead it focused on mortality as a more objective clinical outcome due to the lack of a gold standard to assess pneumonia.

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Despite these limitations, differences in outcomes were not reported after multivariate and sensitivity analyses to control for confounding variables and investigators concluded that prophylactic antimicrobial treatment “does not offer clinical benefit and may generate antibiotic selective pressures that result in the need for escalation of antibiotic therapy.” Therefore, standard supportive care should “remain the mainstay of management of patients with acute aspiration pneumonitis following a macro-aspiration event.”


Dragan V, Wei L, Elligsen M, Kiss A, Walker SAN, Leis JA. Prophylactic antimicrobial therapy for acute aspiration pneumonitis [published online February 9, 2018]. Clin Infect Dis. doi:10.1093/cid/ciy120