Streptococcus pneumoniae isolates relatively insensitive to penicillin G recovered from patients in Switzerland.

The sensitivity to penicillin G of pneumococci isolated in Switzerland has been determined by the quantitative tube dilution method. 3 out of 100 strains were relatively insensitive to this antibiotic (minimum inhibitory concentration greater than 0.1 microgram/ml), thus confirming observations already made in other countries. These results underline the necessity of routinely testing the sensitivity of pneumococci to penicillin G.