A 5-year study of the seroepidemiology of Klebsiella pneumoniae: High prevalence of capsular serotype K1 in Taiwan and implication for vaccine efficacy

Seroepidemiology of Klebsiella pneumoniae was determined for 1000 nonrepeti tive K, pneumoniae isolates collected by a medical center in Taiwan during 1993-1997, Of these, 630 isolates (63%) were from community-acquired infect ions; the rest were from hospital-acquired infections. The isolates were se rotyped according to capsular antigen by countercurrent immunoelectrophores is. About 77% were typeable. Serotypes K1 and K2 accounted for 21.7% and 9. 3% of the isolates, respectively, followed by K57 (5.1%), K54 (4.2%), K21 ( 3.3%), and K16 (3%), The frequency of serotype K1 among bacteremic isolates (30.8%) far exceeded that reported by other investigators worldwide. Molec ular typing of random K1 isolates by pulsed-field gel electrophoresis revea led several different pulsotypes, suggesting a nonclonal spread. This study indicates that a Klebsiella vaccine developed in Europe is not optimal for use in Taiwan because it does not contain the most predominant serotypes-K 1, K54, and K57.