Empirical treatment regimens are devised only after important epidemiological factors are considered, including the pivotal issue as to whether or not there has been recent antimicrobial exposure before obtaining blood cultures. Other key factors that are included in such a decision are the follow- ing: what specific antimicrobial agent was given (if there was prior antimicrobial exposure); determination of the route of acquisition of microbes; whether the infection was community acquired, nosocomial, or non-nosocomial health care associ- ated; what environmental exposures there had been (including injection drug use; Table 9); type of valve infected (whether native or prosthetic) and, if prosthetic, how long it had been implanted; and the clinical course of infection, whether acute, subacute, or chronic. Specific empirical regimens that are considered for use in patients with CNE are listed in Table 8. Because of the major limitations related to administration of therapy that is not specifically pathogen directed, it was the consensus of the writing group that infectious diseases consultation should be obtained in each case of CNE. An infectious diseases consul- tant will review any adverse events related to prior receipt of any drug, types of adverse events, whether there is residual organ damage related to these events or that caused by under- lying medical or surgical conditions, and the potential for clinically important drug interactions with agents other than antimicrobial agents. Recognition of the common causes of IE in specific clini- cal presentations is pivotal (Table 9). For example, in cases of native valve infection acquired in the community with a subacute clinical course, VGS, HACEK organisms, or, less likely, Enterococcus species should be considered. For an acute course of infection in the same setting, S aureus, S pneumoniae, and -hemolytic streptococci are more likely pathogens. Recommendations 1. 