Characterization of German penicillin non-susceptible serotype 23F pneumococci using multilocus sequence typing
Three nationwide multicentre studies (n = 5071) showed an increase in antibiotic resistance in pneumococci in Germany. Serotype 23F was the predominant serotype (n = 45, 22.4 %), followed by 6B (n = 30, 14.9 %) and 9V (n = 19, 9.5 %). Multilocus sequence typing was used to characterize 45 serotype 23F strains with reduced penicillin susceptibility. The Spanish23F-1 clone [profile 4-4-2-4-4-1-1, sequence type (ST) 81] contributes significantly to the emergence of penicillin resistance in Germany (n = 21, 46.7 % of all penicillin non-susceptible serotype 23F isolates). Isolates of ST 277 (profile 7-13-8-6-6-12-8), which has been found previously in the Netherlands, are also observed, particularly in western Germany (n = 8, 17.8 %). A high proportion of strains (n = 11, 24.4 %) have sequence types that have not been reported to date from other countries (STs 353-362). The major penicillin-resistant clones are present in Germany, a country with relatively low levels of β-lactam resistance.