A MULTICENTER STUDY OF THE ANTIMICROBIAL SUSCEPTIBILITY OF COMMUNITY-ACQUIRED LOWER RESPIRATORY-TRACT PATHOGENS IN THE UNITED-STATES, 1992-1994 - THE ALEXANDER PROJECT

A multicenter, collaborative study was performed over a three-year per iod (1992-1994) to determine the antimicrobial susceptibilities of iso lates of Haemophilus influenzae, Moraxella catarrhalis, and Streptococ cus pneumoniae from community-acquired lower respiratory tract infecti ons. Isolates were collected from five geographically separated medica l centers in the United States and sent to a central laboratory for an timicrobial susceptibility testing. Of 350, 536, and 372 isolates of H . influenzae collected from the five centers in 1992, 1993, and 1994, 26.3%, 28.2%, and 30.1%, respectively, were beta-lactamase-positive. A ll isolates of H. influenzae remained susceptible to ceftriaxone, doxy cycline, ciprofloxacin, and ofloxacin over the three-year period. Betw een 95 and 100% of isolates of H. influenzae remained susceptible to a moxicillin-clavulanic acid cefixime, clarithromycin, and chloramphenic ol over this same period. The prevalence of beta-lactamase-positive is olates of M. catarrhalis increased from 92.1% in 1992 to 93.8% in 1993 and to 96.5% in 1994; however, isolates of this species were highly s usceptible to amoxicillin-clavulanic acid, the cephalosporins, the mac rolides, the fluoroquinolones, chloramphenicol, doxycycline, and trime thoprim-sulfamethoxazole. The prevalence of penicillin-intermediate is olates of S. pneumoniae decreased from 16% in 1992 to 8.2% in 1994, wh ereas that of penicillin-resistant isolates increased from 5.6% to 10. 9% in the same period. Ceftriaxone susceptibility declined from 95.2% to 88.4% over the three years, whereas chloramphenicol susceptibility declined from 98.4% to 90.5% and that of trimethoprim-sulfamethoxazole declined from 85.6% to 68.7%. Macrolide activity remained unchanged. (C) 1996 Elsevier Science Inc.