title: Clinical spectrum and molecular characteristics of Klebsiella pneumoniae causing community-acquired extrahepatic abscess.
abstract: OBJECTIVE
  Klebsiella pneumoniae causes a wide spectrum of infections, including abscess and non-abscess formation. This study investigated the clinical spectrum and molecular characteristics of community-acquired Klebsiella infection with primary extrahepatic abscess.
  
  
  METHODS
  From April 2004 through March 2007, a total of 18 strains of K. pneumoniae, 11 from blood and 7 from focal purulent specimens, were recovered from a medical center in southern Taiwan. The clinical data were collected from medical records. Hypermucoviscosity phenotype was defined as positive string test. The virulence genes, including rmpA (regulator of mucoid phenotype), magA (specific to K1 capsule serotype), k2A (specific to K2 capsule serotype), and kfu (an iron uptake system) were amplified by polymerase chain reaction using specific primers.
  
  
  RESULTS
  Twelve men and 6 women with ages ranging from 37 to 74 years were enrolled. Fifteen patients had underlying diabetes mellitus. The duration of hospitalization ranged from 1 to 96 days. Three patients died by the end of treatment. All of the K. pneumoniae strains carried rmpA and 16 strains showed the hypermucoviscosity phenotype. Of the 18 strains, 7 strains were positive for k2A and 4 strains carried magA. kfu was identified in 4 magA-positive strains and 2 magA-negative/k2A-negative strains.
  
  
  CONCLUSIONS
  Diabetes mellitus was the most frequent underlying disease among our patients. The rmpA and/or hypermucoviscosity phenotype were the most common virulence factors in K. pneumoniae isolates causing extrahepatic abscesses, among which K2 capsule serotype (k2A+) was more prevalent than K1 capsule serotype (magA+).
authors.affiliation: Division of Infectious Disease, Department of Internal Medicine, Chi Mei Medical Center, Liouying, Taiwan.
authors.forename: Yee-Huang
authors.initials: YH
authors.lastname: Ku
authors.forename: Yin-Ching
authors.initials: YC
authors.lastname: Chuang
authors.forename: Wen-Liang
authors.initials: WL
authors.lastname: Yu
mesh_terms: D000038:Abscess / Q000382:microbiology*; D000328:Adult; D000368:Aged; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D016667:Bacterial Capsules / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics; D017714:Community-Acquired Infections / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000382:microbiology*; D015897:Comorbidity; D003920:Diabetes Mellitus; D005260:Female; D006801:Humans; D007710:Klebsiella Infections / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000382:microbiology*; D007711:Klebsiella pneumoniae / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification*; D008100:Liver Abscess / Q000382:microbiology; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D011859:Radiography; D013624:Taiwan
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; C501254:MagA protein, Klebsiella pneumoniae; C512267:RmpA protein, Klebsiella pneumoniae; C068924:capsular polysaccharide K2