A multicentre collaborative study of the antimicrobial susceptibility of community-acquired, lower respiratory tract pathogens 1992-1993: The Alexander Project
The Alexander Project is a unique, international, collaborative antimicrobial susceptibility surveillance study of bacterial pathogens causing community-acquired lower respiratory tract infection. Fifteen centres, 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 antimicrobials using the Sensititre microbroth incorporation technique. Of the total of 6385 isolates collected, Haemophilus influenzae (2718), Streptococcus pneumoniae (1856) and Moraxella catarrhalis (818) were the most frequently identified pathogens. Staphylococcus aureus (690), Haemophilus parainfluenzae (183) and Klebsiella pneumoniae (120) were identified less commonly. High-level penicillin resistance in S. pneumoniae (MIC ≧2mg/L) was found in 222 isolates, an overall prevalence of 12% which varied from S. pneumoniae an overall prevalence of 12.3%, with individual centre prevalence varying widely (EU, 0–52.3%; USA, 0–20.9%) and not always following that of high-level resistance. Resistance to other, unrelated, antimicrobials, except notably the fluoroquinolones, was strongly associated with β-lactam resistance. β-Lacta-mase production was detected in 492 isolates of H. influenzae, an overall prevalence of 18.1%. Rates of detection varied widely between centres from 1.4% in Weingarten, Germany in 1993 to 38.5% in Barcelona, Spain in 1992. In general, the prevalence of β-Lactamase production was higher and less variable in USA centres than in those of the EU. β-Lactamase was detected consistently in the majority of isolates of M. catarrhalis with an overall prevalence of 81.7%. Virtually no other resistance phenotype was recognised in this species. Of the 690 collected, most isolates of S. aureus produced β-Lactamase with rates of detection varying from 52.2%–89.1%. Isolates from two centres, Genoa, Italy in 1992 and Paris, France in 1993, were associated with a high prevalence of methicillin-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 analysis of trends in resistance, the study participants have continued to collect further isolates in 1994 and 1995 which will be reported in the future.