Clinical implications of vancomycin-resistant Enterococcus faecium (VRE) with VanD phenotype and vanA genotype.
OBJECTIVE
To investigate the clinical implications of vancomycin-resistant Enterococcus faecium (VRE) with VanD phenotype and vanA genotype (VanD-vanA VRE).


METHODS
We tested in vitro and in vivo efficacies of teicoplanin against VanD-vanA VRE strains. Change in teicoplanin MICs was monitored during incubation with teicoplanin. In vitro and in vivo time-kill assay and survival analysis using a mouse peritonitis model were performed.


RESULTS
Teicoplanin MICs of VanD-vanA VRE strains increased to 128 mg/L within 48 h when they were cultured with 120 mg/L teicoplanin. In vitro and in vivo time-kill assay showed that VanD-vanA VRE strains were not eliminated by 120 mg/L teicoplanin in contrast to vancomycin-susceptible E. faecium and VanD-vanB strains. The survival rate of mice infected with VanD-vanA VRE strains treated with teicoplanin was comparable with that of untreated mice.


CONCLUSIONS
Data suggest that teicoplanin would fail in the treatment of VanD type VRE infections if the strains contained the vanA gene, which cannot be detected in the clinical microbiology laboratory.
Song
Jae-Hoon
JH
Division of Infectious Diseases, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea. jhsong@ansorp.org
Ko
Kwan Soo
KS
Suh
Ji Yoeun
JY
Oh
Won Sup
WS
Kang
Cheol-In
CI
Chung
Doo Ryeon
DR
Peck
Kyong Ran
KR
Lee
Nam Yong
NY
Lee
Wee Gyo
WG
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology / Q000627:therapeutic use*; D001426:Bacterial Proteins / Q000235:genetics*; D001769:Blood / Q000382:microbiology; D019729:Carbon-Oxygen Ligases / Q000235:genetics*; D015169:Colony Count, Microbial; D016984:Enterococcus faecium / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D005260:Female; D016908:Gram-Positive Bacterial Infections / Q000188:drug therapy / Q000382:microbiology; D051379:Mice; D008813:Mice, Inbred ICR; D008826:Microbial Sensitivity Tests; D050296:Microbial Viability; D010538:Peritonitis / Q000188:drug therapy / Q000382:microbiology; D016019:Survival Analysis; D017334:Teicoplanin / Q000494:pharmacology* / Q000627:therapeutic use*; D020713:Vancomycin Resistance / Q000235:genetics*
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; C071437:VanA ligase, Bacteria; D017334:Teicoplanin; D019729:Carbon-Oxygen Ligases