Because of the complexities of IE caused by S pneu- moniae, consultation with an infectious diseases spe- cialist is recommended (Class I; Level of Evidence C). 6. For IE caused by S pyogenes, 4 to 6 weeks of therapy with aqueous crystalline penicillin G or ceftriaxone is reasonable; vancomycin is reasonable only in patients intolerant of -lactam therapy (Class IIa; Level of Evidence C). 7. For IE caused by group B, C, or G streptococci, the addition of gentamicin to aqueous crystalline peni- cillin G or ceftriaxone for at least the first 2 weeks of a 4- to 6-week treatment course may be considered (Class IIb; Level of Evidence C). 8. Consultation with an infectious diseases specialist to guide treatment is recommended in patients with IE caused by -hemolytic streptococci (Class I; Level of Evidence C). Staphylococci IE may be caused by staphylococci that are coagulase positive (S aureus) or coagulase negative (S epidermidis, S lugdunen- sis, and various other species). Although coagulase-positive staphylococci were traditionally believed to cause primarily NVE and coagulase-negative staphylococci (CoNS) were associated with PVE, considerable overlap now exists. For example, in a multicenter, prospective, observational investi- gation involving >1000 consecutive patients with definite IE from >20 countries, S aureus was the most common cause of PVE (25.8% of 214 cases), whereas 64 cases of NVE (8%) resulted from CoNS.136 In addition, the prevalence of CoNS NVE appears to be increasing.137 Thus, it is important to con- sider both pathogen groups when a patient with suspected IE has a preliminary blood culture that suggests staphylococci by Gram stain interpretation. 