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Antibiotic Exposure Is Not Associated With Clearance of Bronchoalveolar Growth: Results From a Prospective
Richard D Betzold1, Bradley M Dennis2, Seth A Bellister3
1137889R Adams Cowley Shock Trauma Center, University of Maryland Medical System, Baltimore, MD, USA.
Background:
Ventilator-associated pneumonia is poorly understood in trauma. Ventilated trauma patients can develop bacterial burden without symptoms; the factors that influence this are unknown.
Methods:
Injured adults ventilated for > 2 days were enrolled. Mini-bronchoalveolar lavage was performed for 14 days or until extubation. Semi-quantitative cultures were blinded from clinicians. All cultures with > 104 colony forming units (CFU) were assessed for antibiotic exposure (ABXE) and spectrum of coverage. mBAL CFU was assessed daily.
Results:
60 patients were ventilated for 9 days (median). There were 75 with > 104 CFU. 46 had > 104 CFU and no ABXE on the sample day. 74% had clearance or a decrease (CoD) in CFU without ABXE. 29 had > 104 CFU and ABXE on the sample day. 19 had ABXE with pathogen coverage. 84% had CoD in CFU. 10 had ABXE with no spectrum of coverage. 1/10 had increased CFU and the remaining 9/10 CoD in CFU. The three groups were not statistically different on chi-squared analysis.
Conclusion:
Clearance of pathogens on surveillance cultures was unaffected by ABXE.
Insights
Antibiotic exposure did not affect pathogen clearance in ventilated trauma patients. Bacterial burden decreased regardless of antibiotic use, suggesting other factors influence outcomes.
Area of Science:
- Critical Care Medicine
- Infectious Diseases
- Trauma Surgery
Background:
- Ventilator-associated pneumonia (VAP) in trauma patients is not well understood.
- Trauma patients on ventilators may have bacterial growth without symptoms, with unknown influencing factors.
Purpose of the Study:
- To investigate the impact of antibiotic exposure on pathogen clearance in ventilated trauma patients.
Main Methods:
- Mini-bronchoalveolar lavage (mBAL) cultures were performed daily for up to 14 days in ventilated adult trauma patients.
- Cultures with >10^4 colony forming units (CFU) were assessed for antibiotic exposure (ABXE) and spectrum of coverage.
- Clearance or decrease (CoD) in CFU was evaluated in relation to ABXE.
Main Results:
- 74% of patients with high CFU and no antibiotic exposure showed clearance or decrease.
- 84% of patients with high CFU and antibiotic exposure with pathogen coverage showed clearance or decrease.
- Clearance rates were not statistically different between groups with and without antibiotic exposure.
Conclusions:
- Antibiotic exposure did not significantly impact the clearance of pathogens in surveillance cultures among ventilated trauma patients.
- These findings suggest that factors beyond antibiotic use influence bacterial burden in this population.
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