Clinical implications of vancomycin-resistant Enterococcus faecium (VRE) with VanD phenotype and vanA genotype

• Published in: Journal of antimicrobial chemotherapy 2008-04, Vol.61 (4), p.838-844
• Main Authors: Song, Jae-Hoon, Ko, Kwan Soo, Suh, Ji Yoeun, Oh, Won Sup, Kang, Cheol-In, Chung, Doo Ryeon, Peck, Kyong Ran, Lee, Nam Yong, Lee, Wee Gyo
• Format: Article
• Language: English
• Subjects: Animals; Anti-Bacterial Agents - pharmacology; Anti-Bacterial Agents - therapeutic use; Antibiotics; Antibiotics. Antiinfectious agents. Antiparasitic agents; Bacteria; Bacterial Proteins - genetics; Biological and medical sciences; Blood - microbiology; Carbon-Oxygen Ligases - genetics; Chemotherapy; Colony Count, Microbial; Drug resistance; Enterococcus faecium; Enterococcus faecium - drug effects; Enterococcus faecium - genetics; Enterococcus faecium - isolation & purification; Female; Genotype & phenotype; Gram-Positive Bacterial Infections - drug therapy; Gram-Positive Bacterial Infections - microbiology; Medical sciences; Mice; Mice, Inbred ICR; Microbial Sensitivity Tests; Microbial Viability; Peritonitis - drug therapy; Peritonitis - microbiology; Pharmacology. Drug treatments; Survival Analysis; teicoplanin; Teicoplanin - pharmacology; Teicoplanin - therapeutic use; Vancomycin Resistance - genetics; vancomycin-resistant enterococci; VanD-vanA
• ISSN: 0305-7453; 1460-2091
• DOI: 10.1093/jac/dkn025

Objectives 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. Conclusion 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.