European Society of Mycobacteriology - Instituto Nacional de Saúde ...

PP-26
AN INCREASE OF DRUG RESISTANCE SINCE 2001
IN MULTIDRUGRESISTANT M. tuberculosis ISOLATES FROM BELGIUM
Karolien Stoffels, Maryse Fauville-Dufaux
Reference Laboratory of Tuberculosis and Mycobacteria, Scientific Institute of Public Health, 642 Rue Engeland, 1180
Brussels, Belgium. Tel. +32-23733210 | Fax. +32-23733281.
kstoffels@iph.fgov.be, mfauville@iph.fgov.be
Between January 1994 and December 2008, MDR clinical isolates of 174 patients were analyzed in our National Reference
Laboratory. They represent 90% of all the MDR-TB patients identified in Belgium during this 15-years period. Since 2000,
the number of MDR patients identified in our country is stable (in average 16 per year, i.e. an average of 1,3 % of the
patients tested for susceptibility to drugs) but the isolates are resistant to more and more second line drugs. We observe
a dramatically increase in resistance to ethambutol, rifabutin, amikacin and ofloxacin, as well as to pyrazinamid.
We divided the studied period in 2 ranges, 1994 to 2000 and 2001 to 2008. Only the first MDR clinical isolate of each patient
was taken into account. So these results do not consider the evolution of the isolates during treatment in Belgium,
but only the initial MDR resistance profile.
In the second period (2001 to 2008) 75,6% of the MDR clinical isolates showed resistance to ethambutol versus
45,5% in the first period (increase of resistance of 30,1%); 75,4% were resistant to rifabutin versus 70,4% in the first
period (increase of 5%). Resistance to pyrazinamid increased from 39,6% to 55,6% (difference of 16%). Resistance
level to amikacin showed an increase of 12,2% (3,6% to 15,8%) and resistance level to ofloxacin showed an increase
of 8,6% (3,6% to 12,2%).
No primary XDR isolate was observed during the first period, but 5 were detected since 2001. Three MDR isolates developed
into XDR what the total amount of XDR strains brought to 6 and only 2 for respectively the second and first period.
Concerning the genetic families identified, 14,7% more Beijing strains were registered in the second period compared to
the first period. A decrease of the members of the LAM and Haarlem family was noted (16,4% and 17,3%).
In conclusion, an important increase of resistance to ethambutol, pyrazinamid, amikacin and ofloxacin is observed in MDR
clinical isolates detected in Belgium. This confirms the urgent need for new anti-tuberculosis drugs.
98 ESM 2009