Klebsiella pneumoniaeBacteremia and Capsular Serotypes, Taiwan

Capsular serotypes of 225 Klebsiella pneumoniae isolates in Taiwan were identifi ed by using PCR.Patients infected with K1 serotypes (41 isolates) had increased community-onset bacteremia, more nonfatal diseases and liver abscesses, lower Pittsburgh bacteremia scores and mortality rates, and fewer urinary tract infections than patients infected with non-K1/K2 serotypes (147 isolates).K lebsiella pneumoniae bacteria cause a variety of infections (1,2).Geographic differences in this organism have been recognized, and a high prevalence of liver abscesses has been observed for >20 years in persons in Taiwan infected with K. pneumoniae (3,4).K1 and K2 are the major capsular serotypes that cause liver abscesses and have increased virulence (4-7).In contrast, only limited information is available about serotypes causing K. pneumoniae bacteremia (3,5).Yu et al. grouped K1 and K2 serotypes and compared clinical characteristics for patients with K. pneumoniae bacteremia with those for patients infected with non-K1/ K2 serotypes (3).Recent evidence suggests that K1 is a major cause of primary liver abscesses and has greater potential for causing metastasis, and that K2 is a major cause of secondary liver abscesses (6,8).We examined the distribution and clinical characteristics of serotypes that cause K. pneumoniae bacteremia from 225 patients (9) and performed PCR-based genotyping to identify capsular serotypes (10).