Estimation of resistance of M.tuberculosis different genotypes to disinfectants

To prevent the speeding on the nosocomial TB this are widely used chemical disinfectants. <b>Aim:</b> Estimation of resistance of <i>Mtb</i> different genotypes to disinfectants. <b>Material and Methods:</b> 30 multidrug-resistant cultures of <i>Mtb</i>: 10 isolates each of genotypes <i>Beijing, LAM, Ural</i>, isolated from patients. Disinfectants: solutions of quaternary ammonium compounds (QACs) with a concentration of active substance: 0.075-0.26%; solutions of hydrogen peroxide with peracid with a concentration of active substance: 0.05-1.1%. Mtb resistance to disinfectants was estimated following the UNE-EN 14348 standard and tissue test-object method (exposition time: 60 minutes). According to guidelines, the disinfectant is effective when ≥10⁵-fold reduction (5 log10) occurs in the number of mycobacterium in the case of basic mycobactericidal activity. <b>Results:</b> Mycobactericidal activity for each of genotypes was obtained after contact of QACs with a concentration 0,26% (p&lt;0.05). Though, <i>Mtb</i> of genotype <i>Beijing</i> were resistant to concentration 0,075%, <i>Lam</i> – 0,15%, <i>Ural</i> – 0,22%. After contact of hydrogen peroxide with peracid - with a concentration 1,1% (p&lt;0.05). However, <i>Mtb</i> of genotypes <i>Beijing</i> and <i>Ural</i> were resistant to concentration 0,8% and genotype <i>Lam</i> – 0,6%. <b>Conclusions:</b> The greatest resistance to QACs was observed on <i>Ural</i> and <i>Lam</i> genotypes. <i>Beijing</i> genotype showed the lowest resistance. To hydrogen peroxide with peracid the greatest resistance was observed on <i>Ural</i> and <i>Beijing</i> genotypes. <i>Lam</i> genotype showed the lowest resistance. Although, mycobactericidal activity was detected in both tested disinfectants, <i>Mtb</i> of different genotypes has different levels of resistance to various chemical groups of disinfectants.