CORRESPONDENCE • CID 2007:45 (1 December) • 1531 cations in the study by Fang et al. [1] were all from cryptogenic PLA, 43 (81%) of 53 and 6 (11%) of 53 isolates had K1 and K2 serotype, respectively. Among them, 19 and 2 of the K1 and K2 isolates, respec- tively, had endophthalmitis and menin- gitis. Thus, 19 (43%) of 43 and 2 (33%) of 6 patients with K1 and K2 liver abscess, respectively, had further complications. Therefore, K2 strains play an important role and not a minor or nonsignificant role. The authors should clarify the origin of those complicated cases. If not, the analysis will become inconclusive and un- certain. However, for either of the situa- tions above, K2 is still an important factor for complications or liver abscess. Finally, if serotyping for the K antigen is used only to differentiate K1 from non- K1 K. pneumoniae, detection could be done within 10 min by a simple antiserum Quellung test. PCR detection should not be the rapid test used to differentiate se- rotype K1 and non-K1 K. pneumoniae. Antiserum could also be purchased easily, as described in the previous study by Chuang et al. [6]. Acknowledgments Potential conflicts of interest. All authors: no conflicts. Chang-Phone Fung 1 and L. K. Siu 2 1 Institute of Clinical Medicine, National Yang-Ming University, Taipei Veterans General Hospital and Chutung Veterans Hospital, and 2 Division of Clinical Research, National Health Research Institutes, Taipei, Taiwan References 1. Fang C-T, Lai S-Y, Yi W-C, Hsueh P-R, LiuK- L, Chang S-C. Klebsiella pneumoniae genotype K1: an emerging pathogen that causes septic ocular or central nervous system complications from pyogenic liver abscess. Clin Infect Dis 2007; 45:284–93. 2. Fung CP, Chang FY, Lee SC, et al. A global emerging disease of Klebsiella pneumoniae liver abscess: is serotype K1 an important factor for complicated endophthalmitis? Gut 2002; 50: 420–4. 3. Chung DR, Lee SS, Lee HR, et al. Emerging invasive liver abscess caused by K1 serotype Klebsiella pneumoniae in Korea. J Infect 2007; 54:578–83. 4. Yeh KM, Kurup A, Siu LK, et al. Capsular se- rotype K1 or K2, rather than magA and rmpA, is a major virulence determinant for Klebsiella pneumoniae liver abscess in Singapore and Tai- wan. J Clin Microbiol 2007; 45:466–71. 5. Fang CT, Chuang YP, Shun CT, Chang SC, Wang JT. A novel virulence gene in Klebsiella pneumoniae strains causing primary liver ab- scess and septic metastatic complications. J Exp Med 2004; 199:697–705. 6. Chuang Y-P, Fang C-T, Lai S-Y, Chang S-C, Wang JT. Genetic determinants of capsular se- rotype K1 of Klebsiella pneumoniae causing pri- mary pyogenic liver abscess. J Infect Dis 2006; 193:645–54. 7. Yeh K-M, Chang F-Y, Fung C-P, Lin J-C, Siu LK. Serotype K1 capsule, rather than magA per se, is really the virulence factor in Klebsiella pneumoniae strains that cause primary pyo- genic liver abscess. J Infect Dis 2006; 194:403–4. Reprints or correspondence: Dr. L. K. Siu, Div. of Clinical Research, National Health Research Institutes, Taipei, Taiwan (klksiu@gmail.com). Clinical Infectious Diseases 2007; 45:1530–1  2007 by the Infectious Diseases Society of America. All rights reserved. 1058-4838/2007/4511-0027$15.00 DOI: 10.1086/525000 The Distant Metastasis of Pyogenic Liver Abscess Caused by Klebsiella pneumoniae Serotype K2 and the Underlying Disease of Diabetes Mellitus Should Be Carefully Interpreted To the Editor—A recent article by Fang et al. [1] mentioned that diabetes mellitus (DM) is not a significant risk factor for septic ocular or CNS complications in Klebsiella pneumoniae liver abscess (KP- LA). In the study by Fang and colleagues, 13 (57%) of 23 patients with distant me- tastasis to eye or CNS were affected with DM. Previous studies showed that 67%– 95.5% of the KP-LA–affected patients with distant metastasis were affected with DM [2–5]. In 2 studies, with overall enrollment of 354 patients with KP-LA, DM was ver- ified as a significant factor for developing severe extrahepatic complications [4, 5] and poor visual outcome of endophthal- mitis [5]. We suggest that subjects with DM should not be ignored in the future study of KP-LA and that the definition of severe metastatic complications of KP-LA should not be confined to eye and CNS only. Although the introduction in the article by Fang et al. [1] provided references to support the low prevalence of DM among subjects with liver abscess, all references have at least 64% of patients with KP-LA had DM (see the references [6–9], which Fang et al. [1] cited). The only reference from Korea [10], with ∼40% of patients affected with DM, actually mentioned that DM was at highest prevalence among all underlying diseases. Taken together, the work of Fang and colleagues seems to completely misrepresent the significance of DM in KP-LA. Fang et al. [1] disagree with our con- clusions that K1/K2 is a major virulence factor, conclusions that are based on our findings from an in vitro neutrophil phag- ocytosis model and an animal lethality study [11, 12]; we used isolates from 2 geographical regions. Instead, Fang and colleagues concluded that K1 only (and not K2) was the major virulence factor, conclusions that were based on their re- sults from a serum-resistance assay of K1 and K2 isolates from their single hospital [1]. Might the results of their in vitro assay of serum resistance be less pertinent than the findings of virulence from the animal model? In the study by Mizuta et al. [13], K1 strains had lower virulence than did K2 strains. Although 2 strains of K2 iso- lates from the study by Mizuta et al. [13] were avirulent, 7 of 9 K2 isolates did cause lethality with !10 colony-forming units. It is also interesting that 1 patient infected with a serum-sensitive K1 strain in the study by Fang et al. [1] developed endo- phthalmitis that led to loss of vision. Although we highlight the fact that se- rotypes K1 and K2 play an important role in KP-LA, as well as the extrahepatic com- plications [2, 11], the significance of in- teractions between the virulence of K. pneumoniae and DM should not be ig- nored [12]. We should not exclude the associated factors other than serotypes that were involved in the KP-LA, because non– K1/K2 KP-LA still has an unknown eti- ology that magA or serotypes cannot explain. Downloaded from https://academic.oup.com/cid/article-abstract/45/11/1531/335572 by guest on 01 June 2020