The Alexander Project 1996-1997: latest susceptibility data from this international study of bacterial pathogens from community-acquired lower respiratory tract infections

The Alexander Project was established in 1992 to examine antimicrobial susc eptibilities of bacterial isolates from community-acquired infections of th e lower respiratory tract. Testing of a range of compounds was undertaken i n a central laboratory. From 1992 to 1995, isolates were collected from geo graphically separated areas in countries in the European Union and various states in the USA. In 1996, the study was extended to include centres in Me xico, Brazil, Saudi Arabia, South Africa, Hong Kong and other European coun tries not included previously. Data generated by the project during 1996-19 97 confirm France and Spain as European centres with high rates of resistan ce to penicillin among isolates of Streptococcus pneumoniae. Both intermedi ate (MIC 0.12-1 mg/L) and resistant (MIC greater than or equal to 2 mg/L) p henotypes are present. Combined resistance rates (intermediate and resistan t) were >50% in 1997. Combined resistance rates in excess of 20% were found in the Republic of Ireland, Portugal, the Slovak Republic and Hungary. Pen icillin resistance continues to evolve in the USA, with combined resistance rates of 16.4% (1996) and 18.6% (1997). In the new, non-European centres, e.g. Mexico and, in particular, Hong Kong (where resistant strains accounte d for 50% of all isolates of S. pneumoniae in 1996 and 55.5% in 1997), ther e are centres where rates of resistance are high. Macrolide resistance is i ncreasing generally among both penicillin-resistant and penicillin-suscepti ble isolates of S. pneumoniae. There is variation between countries, and in four out of the 16 centres for which both 1996 and 1997 data are available , rates of macrolide resistance have fallen. Overall, the percentage of S. pneumoniae strains that is resistant to macrolides exceeds the percentage t hat is resistant to penicillin. In 1996, 16.5% of all S. pneumoniae isolate s were resistant to macrolides compared with 10.4% resistant to penicillin, and in 1997 respective rates were 21.9% and 14.1%. beta-Lactamase producti on was the principal mechanism of resistance observed among isolates of Hae mophilus influenzae. However, considerable variation in the percentage of i solates producing beta-lactamase (0-37.1%) was observed within this species . Within Europe, in the Republic of Ireland, France and Belgium, more than 15% of isolates were beta-lactamase producers. In Spain rates were as high as 31.7%. Outside Europe and the USA high rates were described in Mexico (2 5%), Saudi Arabia (27.9%, 16.7%) and Hong Kong (37.1%, 28.9%). Of H. influe nzae from the USA, 30.4% were beta-lactamase producers in 1996 and 23.3% in 1997. beta-Lactamase production among isolates of Moraxella catarrhalis wa s observed in >90% of the isolates tested in 1996 and 1997.