1. SUPRA-NATIONAL REFERENCE LABORATORY NETWORK
DST QA Round 11, 2004
A. Van Deun & F. Portaels

2. CONDUCT OF ROUND 11 20 strains, 10 in duplicate: total 30 cultures
non-MDR series: R-mono
7 strains from Borstel, 6 from Paris SRL
pre-testing 7 Antwerp strains
MIC, sequencing
exclusion doubtful strains
mass culture from single colony
0 contamination, 9 growth failures (#3, #9)

3. LABS AND METHODS, Rd 6 TO 11

4. JUDICIAL RESULTS OF ROUND 11
INH
strains: 10 resistant, 10 susc.
cultures: 15 resistant, 15 susc.
agreement:
100% strains
98% strains

5. JUDICIAL RESULTS OF ROUND 11
RIFAMPICIN
10 resistant, 10 susceptible strains
16 resistant, 14 susceptible cultures
agreement:
100% strains
57% (judicial susc.) 1 strain (#6)

6. JUDICIAL RESULTS OF ROUND 11
STREPTOMYCIN
11 resistant, 9 susceptible strains
16 resistant, 14 susceptible cultures
agreement:
100% strains
96% strains
91% strain
70% strains (#1, 7)
<70% strains (#6, 9)

7. JUDICIAL RESULTS OF ROUND 11
ETHAMBUTOL
strains: 5 resistant, 15 susc.
cultures: 7 resistant, 23 susc.
agreement:
100% strains
90-99% strains
87% strain
70-80% strains (#8, 11, 12)

8. RESULTS OF ROUND 11

9. RESULTS OF ROUND 11

10. RIFAMPICIN INTERMEDIATE RESISTANT STRAIN: results by method

11. COMPARISON PHENO / GENOTYPIC (SEQUENCING)
Results known for 7 Antwerp strains only
Perfect correlation for H and E
Poor correlation for S (rpsL, rrs530, rrs912)
0/3 resistant have mutation
Perfect correlation for R with exception of the discordant strain
leu533pro mutation
majority finds susceptible

12. RIFAMPICIN PROBLEM STRAIN MICs

13. RIFAMPICIN PROBLEM STRAIN: CLINICALLY
#6, judicial HS resistant, 57% R-susceptible
patient from Bujumbura, Burundi
failure of 2EHRZ / 4H3R3
failure of 2SEHRZ / 1EHRZ / 5E3H3R3