Multidrug-resistant pathogens and pneumonia: comparing the trauma and surgical intensive care units

As acute care surgery evolves, more trauma surgeons are caring for critically ill general surgery as well as trauma patients. However, these two populations are unique, and infectious complications may need to be addressed differently, as the causative organisms may not be the same in the two groups. To study this, we evaluated ventilator-associated (VAP) and hospital-acquired (HAP) pneumonia in the trauma (TICU) and general surgical (SICU) intensive care units to investigate differences in the causative pathogens. Our hypothesis was that SICU patients would have a higher incidence of multi-drug-resistant (MDR) organisms causing VAP/HAP, possibly contributing to inadequate empiric antibiotic (IEA) coverage.

Retrospective review of 116 patients admitted with VAP or HAP over a one-year period to the TICU (n = 72) or SICU (n = 44) at a tertiary medical center. Culture was followed by initiation of empiric antibiotics on the basis of an antibiotic algorithm derived from trauma patients. Demographics, illness, and pneumonia characteristics were assessed; MDR organisms were identified.

Multi-drug-resistant organisms caused 30.6% of first pneumonias in the TICU vs. 65.9% in the SICU (p = 0.0002). Subsequent pneumonias were seen in 31.8% of SICU patients and 16.7% of TICU patients (p = 0.0576). Inadequate empiric antibiotic coverage was documented in 38.6% of SICU pneumonias vs. 26.4% in the TICU (p = 0.12).

Multiply-resistant pathogens cause a significantly greater number of VAP/HAPs in the SICU than in the TICU. Associated with this, when using an antibiotic algorithm based on TICU bacterial pathogens, there is a trend toward a greater likelihood of subsequent pneumonias and toward more IEA coverage in the SICU population compared with TICU patients. Our results indicate that these distinct patient populations have different pathogens causing VAP/HAP and affirm the necessity for population-specific algorithms to tailor empiric coverage for presumed VAP/HAP.