Healthcare-associated pneumonia: the state of evidence to date.

PURPOSE OF REVIEW: As evidence about the importance of correct choice of empiric therapy in the setting of pneumonia accumulates, balancing antibiotic spectrum against the risk of selecting for resistant organisms gains importance. Healthcare-associated pneumonia (HCAP) defines a set of risk factors to underscore the probability of a resistant etiologic pathogen, requiring broader spectrum treatment than is generally needed in community-acquired pneumonia (CAP). Controversies persist as to whether HCAP is a useful designation for diagnosis, treatment and outcome prediction. RECENT
FINDINGS: HCAP represents a discrete syndrome, where offending organisms and outcomes differ from those for CAP. However, HCAP designation is neither a sensitive nor a specific system to predict the presence of a resistant organism. Several other instruments have been developed that require prospective validation. Recent findings that CAP guideline-concordant antibiotic treatment among HCAP patients does not alter outcomes is confounded by the emerging understanding that culture-negative HCAP may be successfully treated with therapy targeted at CAP pathogens.
SUMMARY: Because HCAP is an important emerging syndrome, a systematic approach to its study is critical. As evidence in this area evolves, it remains important for investigators and clinicians to identify knowledge gaps and to set the research agenda to resolve multiple unanswered questions.