Resistant organisms such as Methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa (PA) may cause pneumonia in patients presenting to the hospital. Healthcare-associated pneumonia (HCAP) was developed to identify those with community-onset pneumonia but who may be at risk for resistant organisms (ROs). The HCAP paradigm has not been validated in critically ill subjects.
We retrospectively identified persons who, over a 3 yr period, presented to the hospital with pneumonia requiring mechanical ventilation. We only included persons with evidence of bacterial infection (e.g. positive lower respiratory tract cultures, blood cultures, or urinary antigen testing). We compared those with ROs (MRSA, PA, EBSL) to those with other pathogens in terms of demographics, co-morbidities, severity of illness, and risk factors for HCAP. We considered HCAP present if the patient was either immunosuppressed, undergoing hemodialysis, admitted from long-term care (LTC), or had received antibiotics in the last 30 days.
The final cohort included 190 subjects (median age 61 yrs, 54% male) & ROs were seen in 32.6%. Neither demographics, severity of illness, nor most co-morbidities differed between those with ROs and persons with other pathogens. Approximately half of subjects met criteria for HCAP, & ROs were more common in HCAP (71.7% vs. 39.2%, p=0.001). The prevalence of ROs increased among patients with multiple HCAP factors. Those with ≥2 risk factors were 5.9 times more likely to have an RO (95% CI: 2.8–12.3). As a screening test for ROs, HCAP had a poor area under the receiver operating curve (0.66, 95% CI: 0.58–0.75). Logistic regression revealed 2 variables independently associated with ROs: immunosuppression (OR: 4.9, 95% CI: 2.2–10.6) & admission from LTC (OR: 2.4, 95% CI: 1.1–5.1).
Although HCAP identifies patients at increased risk for ROs not all components of the HCAP definition contribute equally to explaining the prevalence of ROs. Refinements to the definition are warranted.
Physicians should consider more focused utilization of broad spectrum antibiotics rather than using them in all patients with HCAP.
Andrew Shorr, Grant monies (from industry related sources) Astellas, GSK, J and J, Pfizer, Sanofi; Consultant fee, speaker bureau, advisory committee, etc. Astellas, BI, GSK, J and J, Medicines Co. Merck, Pfizer, Sanofi, Theravance; No Product/Research Disclosure Information