Utility of eosinophil count as predictor of bacteremia.

I believe that 3 major issues about doxy-cycline are often overlooked. First, updated data on the pharmaco-kinetics of oral doxycycline remain both scarce and controversial. Indeed, whereas Cunha [1] reported peak serum doxycy-cline concentrations of ∼4 mg/mL after administration of a 100-mg oral dose, Sak-ellari et al. [2] observed mean peak serum concentrations of 2.35 mg/mL 2 h after administration of the same dose. Our experience with 6 healthy volunteers who received a 100-mg tablet is closer to that of Sakellari et al. [2], because we observed a mean peak serum level of 1.37 mg/mL 2 h after administration of the dose (Bantar et al., unpublished data). Second, the use of doxycycline for treating outpatients with CAP has probably been promoted on the basis of data published in some guidelines on the in vitro efficacy of this drug against penicillin-resistant strains of S. pneumoniae [3, 4]. However, to my knowledge, results of specific controlled clinical trials involving patients with CAP treated with oral doxy-cycline in an ambulatory manner nor pharmacodynamic studies of the efficacy of doxycycline against S. pneumoniae infection have not been published to date. Third, recommendations on antimicro-bial treatment for treating adults with CAP are highly influenced by the severity of illness, and the presence of bacteremia is seldom taken into account when selecting the primary drug [3–5]. This fact, together with results of clinical trials that demonstrated the overall efficacy of certain drugs, probably led some authorities to recommend that certain therapies be given orally for the treatment of low-risk CAP, even though some of these drugs (i.e., azith-romycin and doxycycline) may reach poor serum levels or display only inhibitory activity [2, 6]. However, caution should be exerted for patients receiving treatment for pneumococcal bacteremia, because delay in achieving bactericidal serum levels could play a crucial role in allowing development of breakthrough pneumococ-cal bacteremia during the course of oral therapy in those at low risk for breakthrough infection, as observed with dox-ycyline in an earlier study [7] and with azithromycin in a more recent study [8]. Although the overall incidence of pneu-mococcal bacteremia among patients with CAP is low (i.e., 10%–20%), several of these patients may belong to a low-risk class. Bantar et al. [5] assessed the distribution of the severity of illness index (as defined by the Pneumonia Outcomes Research Team [PORT] index) for 101 patients with bacteremic pneumonia enrolled in a number of clinical trials …