[Pneumonia caused by resistant pneumococci].

During the last few years, acquired resistance of pneumococci to the main families of normally active antibiotics has appeared. This resistance is now worldwide but unevenly distributed: in Europe, for instance, it predominates in Spain and Hungary. In France, according to the national Registry, resistance to penicillins, which was less than 5 percent in 1988, rose to 16.9 percent in 1991. More than 80 percent of resistant strains are found among 4 stereotypes (6, 9, 19, 23) and more than 50 percent belong to stereotype 23F exclusively. The incidence of penicillin-resistant has been evaluated at 8.5 percent in the year 1991-92. The most significant risk factor is a previous treatment with beta-lactam antibiotics, but some authors also blame frequent pneumonias in the previous year, nosocomial pneumonia, or hospitalization during the previous 3 months. There are no specific clinico-radiological features. The incidence of resistant strains is said to be higher in HIV seropositive subjects. Amoxicillin administered in high doses remains the reference treatment for strains with intermediate susceptibility (minimal inhibitory concentration [MIC] between 0.1 and 1.0 microgram/ml). Strains with a more than 1 microgram/ml MIC require beta-lactam antibiotics such as ceftriaxone, cefotaxime of imipenem in high doses. Pristinamycin still has good in vitro activity on resistant strains. Prevention rests on isolation of infected patients, treatment of healthy carriers and wide prescription of anti-pneumococcus vaccine.