Penicillin-resistant pneumococcal infections

Variable incidence : The incidence of penicillin-resistant pneumococci (PRP) has increased significantly within the last few years and has become a worrisome problem worldwide. However, variations of incidence between countries have been noted. The highest incidences have been reported in Spain, France, and Eastern European countries. in the US, incidence has been increasing, together with a geographical spread. Beta-lactam consumption is higher in France and in Spain than in Germany and in England. Susceptibility tests : Detection of PRP requires reliable techniques. It is recommended to test susceptibility of strains to macrolides (< 5% in the US, but 40 to 50% of PRP are resistant to macrolides in Europe). Treatment : The efficacy of amoxicillin or injectable third generation cephalosporins (cefotaxime or ceftriaxone) are not affected by resistance to penicillin G, and are widely used for PRP. Pharmacological studies in otitis media have confirmed the advantage of amoxicillin and ceftriaxone in terms of pharmacodynamics, with high inhibitory quotients established between local concentrations (middle ear fluid) and MICs for PRP and H, influenzae, predictive of bacterial eradication. Another favorable pharmacodynamic parameter is time above MIC (T>MIC) which was 50 to 100% in these studies. Clinical efficacy : The clinical efficacy of ceftriaxone was confirmed in a French prospective study and was similar to that of amoxicillin, with decreased nasopharyngeal carriage of H. influenzae. Carriage of H. influenzae and PRP in children in day-care centers has been found to be slightly higher in children previously treated within the last 3 months by oral cephalosporins or amoxicillin. These data confirm the importance of surveys on PRP incidence and of controlling beta-lactam consumption.