1. Nocosomial infection with Vancomycin-dependent Enterococci Michelle Nguyen Bioc 230 10/11/04

2. Preview Cases Molecular profiling of VDE Case control study Discussion

3. Case 1 32 y.o woman with h/o type 1 DM, ESRD Kidney-pancreas transplant Post-op infection with VR Enterococcus faecium  Tx with antibiotics Abdominal fluid culture  VR E. faecium that cannot grow w/o Vancomycin Refractory sepsis  death (day 268)

4. Case #2 40 y.o woman with h/o type I DM, ESRD Kidney-pancreas transplant Post-op: VRE from intraabdominal cultures  remove kidney and pancreas Antibiotic tx with IV streptogramins Refractory VRE  death

5. Case #3 47 y.o woman with h/o CML Matched-unrelated donor bone marrow transplant Post-op: severe GVHD, acute renal failure, bacteremia with Corynebacterium  vancomycin UTI with VRE  not eradicated Death due to refractory GVHD with multiple organ failure (day 87)

6. Tip off: what are the common points Nocosomial infections Comorbidities: DM, kidney dysfunction,tranplants post-op complications Bacteremia with VDE Broad use of antibiotics and immunosuppressive drugs (what are the risks??)

7. Characterizing VDE Criteria  VRE: growth in 6ug/ml Vancomycin, MIC>8ug/ml Vanco  VDE: cannot growth without 6ug/ml Vanco with multiple subcultures Molecular profile  Susceptibility testing: Vanco disk, D-ala-D-ala disk  Resistance gene vanA and vanB: PCR  Strain relation (distinct clones?): Pulsed-field gel electrophoresis (PFGE)  Spontaneous reversion from VDE to VRE: serial dilutions of culture grown in Vanco+ broth to Vanco+/- agar plates

8. Susceptibility Test Result VDE Revertant

9. PFGE

10. Molecular profile of VDE Strain: E. faecium Resistance gene: vanA (2), vanB (1) Resistance profile: penicillins, gentamicin, erythromycin Susceptibility: streptogramins, teicoplanin Spontaneous reversion: around 1x10 -6 except for strain 3 (2.6x10 -3 ) Growth not supported by D-ala-D-ala

11. Proposed mechanism for Vancomycin dependence Loss of D-ala-D-ala ligase in VRE strain Vancomycin induces production of D-ala- D-lactate ligase Require prolonged exposure to Vancomycin

12. Case control study 3 patients with nocosomial VDE infection 10 patients with nocosomial VRE infection 10 at-risk patients not infected with enterococci Matched by age and admission to same service

13. Typical case control study design

14. Case study results

16. Specific findings Length of exposure to antimicrobials  Vancomycin  3 rd generation cephalosporins Mortality Gender Exposure to ICU

17. Possible risk factors Intense use of 3 rd generation cephalosporins Renal insufficiency Spontaneous reversion  Vanco discontinuation might not be sufficient to treat VDE infection.