A MULTICENTER COLLABORATIVE STUDY OF THE ANTIMICROBIAL SUSCEPTIBILITYOF COMMUNITY-ACQUIRED, LOWER RESPIRATORY-TRACT PATHOGENS 1992-1993 - THE ALEXANDER PROJECT

The Alexander Project is a unique, international, collaborative antimi crobial susceptibility surveillance study of bacterial pathogens causi ng community-acquired lower respiratory tract infection. Fifteen centr es, ten in the European Union (EU) and five in the USA, each submitted up to 400 isolates per year for 2 years (1992 and 1993) to a central laboratory for re-identification and determination of MICs of 15 antim icrobials using the Sensititre microbroth incorporation technique. Of the total of 6385 isolates collected, Haemophilus influenzae (2718), S treptococcus pneumoniae (1856) and Moraxella catarrhalis (818) were th e most frequently identified pathogens. Staphylococcus aureus (690), H aemophilus parainfluenzae (183) and Klebsiella pneumoniae (120) were i dentified less commonly. High-level penicillin resistance in S. pneumo niae (MIC greater than or equal to 2 mg/L) was found in 222 isolates, an overall prevalence of 12% which varied from <1% in Germany, Italy, UK and two of the five USA centres, to 3.8-40.4% in the remainder, wit h the highest prevalence found in France and Spain. Intermediate penic illin resistance (MIC 0.12-1 mg/L) was identified in 228 isolates of S . pneumoniae, an overall prevalence of 12.3%, with individual centre p revalence varying widely (EU, 0-52.3%; USA, 0-20.9%) and not always fo llowing that of high-level resistance. Resistance to other, unrelated, antimicrobials, except notably the fluoroquinolones, was strongly ass ociated with beta-lactam resistance. beta-Lactamase production was det ected in 492 isolates of H. influenzae, an overall prevalence of 18.1% . Rates of detection varied widely between centres from 1.4% in Weinga rten, Germany in 1993 to 38.5% in Barcelona, Spain in 1992. In general , the prevalence of beta-lactamase production was higher and less vari able in USA centres than in those of the EU. beta-Lactamase was detect ed consistently in the majority of isolates of M. catarrhalis with an overall prevalence of 81.7%. Virtually no other resistance phenotype w as recognised in this species. Of the 690 collected, most isolates of S. aureus produced beta-lactamase with rates of detection varying from 52.2%-89.1%. Isolates from two centres, Genoa, Italy in 1992 and Pari s, France in 1993, were associated with a high prevalence of methicill in-resistance (34.8% and 43.8%, respectively). Combined isolates of H. parainfluenzae and K. pneumoniae accounted for only 4.7% of the total collection. Although the current data are insufficient to allow analy sis of trends in resistance, the study participants have continued to collect further isolates in 1994 and 1995 which will be reported in th e future.