Comparative Evaluation of Orally Active Antibiotics against Community-Acquired Pathogens: a Multi-Center Study in Five Mediterranean Countries

Abstract

In 5 Mediterranean countries 7902 pathogens, all isolated in 1992 and 1993 from community-acquired infections, were studied for susceptibility to the following orally active antibiotics: penicillin G, ampicillin, ampi-cillin + sulbactam, amoxycillin + clavulanic acid (both 2:1 ratio), cefalexin, cefaclor, cefuroxime, cefetamet, doxycycline and erythromycin. Ten centers in Italy, 4 centers in Greece, 3 centers in Spain, and 1 center in Lebanon and Saudi Arabia contributed to this study; all centers used preformed standardized microtiter panels (Sceptor^®, BBL, Heidelberg, FRG). The most frequently isolated pathogens were Escherichia coli (n=1267), Proteus mirabilis (n = 843), Klebsiella pneumoniae (n=771), enteric Salmonella spp. (n=629), Enterobacter cloacae (n = 486), Citrobacter freundii (n = 383), Streptococcus agalactiae (n=346), Haemophilus influenzae (n=298), Streptococcus pyogenes (n=294), Streptococcus pneumoniae (n=246), Klebsiella oxytoca (n=243), and Shigella spp. (n=185). Statistical analysis was performed for each of the above countries and for all pooled data available. The penicillin antibiotics were the most active compounds against the gram-positive cocci, exceeding the MIC₉₀ values 2- to 8-fold over all cephalosporins. Regarding the gram-negatives (above all Klebsiella spp.) cefetamet was by far the most active compound (MIC₉₀ = 1 mg/1). Regarding the percentage of resistant isolates, there were no striking discrepancies between the centers and countries involved in this study. There was, however, complete cross-resistance in penicillin-resistant S. pneu moniae isolates (MIC₉₀ = 2 mg/l). By far the majority of the penicillin-resistant pneumococci showed additional resistance to doxycycline and erythromycin. Regarding all 11 compounds included in this study cefetamet was the only agent with well balanced activity against both gram- positive and gram-negative pathogens.