title: Impacts of Hypervirulence Determinants on Clinical Features and Outcomes of Bacteremia Caused by Extended-Spectrum β-Lactamase-Producing Klebsiella pneumoniae.
abstract: We investigated the implications of hypervirulence determinants on clinical features of 48 adult patients with bacteremia caused by extended-spectrum β-lactamase-producing Klebsiella pneumoniae. Isolates in the hypervirulence group included any of the following virulence determinants: K1/K2 capsule serotypes, hypermucoviscosity phenotype, rmpA gene, or rmpA2 gene. Nonhypervirulence group isolates were negative for all of the above virulence factors. In this study, all isolates used were non-K1/K2 strains. Statistically significant differences were observed in clinical features of patients between the two groups. The hypervirulent isolates (n = 19), including 11 isolates with the hypermucoviscosity phenotype, 15 with the rmpA gene, and 16 with the rmpA2 gene, were more commonly recovered from diabetic patients and mainly manifested as secondary bacteremia (such as pneumonia, urinary tract infections, or other localized infections). The nonhypervirulent isolates (n = 29) were more commonly recovered from patients after prolonged hospital stays (>30 days) and mostly manifested as primary bacteremia. The overall in-hospital mortality was 56.3%. Hazard ratio (HR) analysis revealed the following positive predictors for mortality: nosocomial infection, stay in an intensive care unit, no removal of the central venous catheter, Charlson comorbidity score, and APACHE II score (≧15). The negative predictors were initial appropriate antibiotic therapy (HR 0.42) and urinary tract infection (HR 0.19). Charlson score was an independent confounder based on multivariate analysis (HR 1.43, 95% confidence interval 1.04-1.99). In conclusion, hypervirulence determinants played a role in causing secondary infections in diabetic patients; however, the presence of morbidity cofactors could themselves influence mortality, despite the absence of hypervirulence determinants.
authors.affiliation: 1 Department of Intensive Care Medicine, Chi Mei Medical Center , Tainan City, Taiwan .|2 Department of Medicine, Taipei Medical University , Taipei City, Taiwan .
authors.forename: Wen-Liang
authors.initials: WL
authors.lastname: Yu
authors.affiliation: 3 Department of Medical Research, Chi Mei Medical Center , Tainan City, Taiwan .
authors.forename: Mei-Feng
authors.initials: MF
authors.lastname: Lee
authors.affiliation: 3 Department of Medical Research, Chi Mei Medical Center , Tainan City, Taiwan .
authors.forename: Chi-Chung
authors.initials: CC
authors.lastname: Chen
authors.affiliation: 4 Department of Internal Medicine, Chi Mei Medical Center , Tainan City, Taiwan .|5 Department of Health and Nutrition, Chia Nan University of Pharmacy and Science , Tainan City, Taiwan .
authors.forename: Hung-Jen
authors.initials: HJ
authors.lastname: Tang
authors.affiliation: 3 Department of Medical Research, Chi Mei Medical Center , Tainan City, Taiwan .
authors.forename: Chung-Han
authors.initials: CH
authors.lastname: Ho
authors.affiliation: 3 Department of Medical Research, Chi Mei Medical Center , Tainan City, Taiwan .|6 Department of Internal Medicine, Chi Mei Medical Center-Liou Ying , Tainan City, Taiwan .
authors.forename: Yin-Ching
authors.initials: YC
authors.lastname: Chuang
mesh_terms: D000368:Aged; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D016470:Bacteremia / Q000188:drug therapy / Q000382:microbiology*; D001426:Bacterial Proteins / Q000235:genetics; D003428:Cross Infection / Q000188:drug therapy / Q000382:microbiology; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D007710:Klebsiella Infections / Q000188:drug therapy / Q000382:microbiology*; D007711:Klebsiella pneumoniae / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D065288:Serogroup; D014552:Urinary Tract Infections / Q000188:drug therapy / Q000382:microbiology; D037521:Virulence Factors / Q000235:genetics*; D001618:beta-Lactamases / Q000235:genetics*
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D037521:Virulence Factors; D001618:beta-Lactamases
keywords: ESBL; Klebsiella pneumoniae; hypermucoviscosity; hypervirulence; rmpA; virulence