[Moraxella catarrhalis: virulence and resistance mechanisms].

It is more than a century ago that Moraxella catarrhalis was discovered and described in some detail. However, it was not until the last decade that M. catarrhalis was recognized as a facultative pathogen, namely in otitis media (predominantly in children), sinusitis and nosocomial pneumonia in the group of elderly, debilitated patients.

Sulbactam and clavulanic acid: enzyme kinetics and synergy with ampicillin and mezlocillin.

The two beta-lactamase inhibitors, sulbactam and clavulanic acid, exhibit high affinity (K(I) < 10(-6)mol/l) for the beta-lactamases of Gram-negative organisms with predominantly penicillinase activity and much less affinity (especially clavulanic acid) for organisms with predominantly cephalosporinase activity. In tests to compare the synergy of these beta-lactamase inhibitors with other antibiotics, clavulanic acid and ampicillin or mezlocillin demonstrated greater synergy than sulbactam and ampicillin or mezlocillin, with isolates forming either a plasmid-coded beta-lactamase or a chromosomal enzyme with predominantly penicillinase activity. However, neither sulbactam nor clavulanic acid were able to protect ampicillin or mezlocillin adequately against inactivation by beta-lactamase overproducing variants of Klebsiella pneumoniae or Klebsiella oxytoca, irrespective of the extent of synergy seen with the corresponding wild strains.

Comparative evaluation of orally active antibiotics against community-acquired pathogens: results of eight European countries.

In this multicenter study conducted in eight European countries, 13,173 pathogens--all isolated from community-acquired infections in 1992 and 1993--were evaluated for their susceptibility to the following orally active antibiotics: penicillin G, ampicillin, amoxycillin plus clavulanic acid, cefaclor, cefuroxime, cefetamet, doxycycline and erythromycin. Ten centers in Italy, five in Germany, in the Netherlands and Switzerland, four in Greece and Spain, three in Hungary and one in Finland contributed to this study; ready-to-use standardized microtiter panels (Sceptor system, BBL, Heidelberg, Germany) were used throughout all assays. The most frequently encountered species were: Escherichia coli, Proteus mirabilis, Klebsiella pneumoniae and non-typhoid Salmonella spp.

Comparative evaluation of orally active antibiotics against community-acquired pathogens: a multi-center study in five Mediterranean countries.

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, ampicillin + 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 performed 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.