Por:
Natalia; Lopez Castaño Villegas
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Fecha:
2018
Abstract:
Background: Multidrug resistant TB cases have been on the rise, risking advances in TB prevalence and control. Early diagnosis and targeted initial treatment are paramount for effective management and control of spreading of MDR/XDR-TB cases Methods: 161 isolates from patients with L-J culture confirmed TB in Lima, Peru, were tested with MODS+ assay, the diagnostic test and Sensititre, the reference standard. Analysis of growth patterns of bacteria in both methods were used to determine susceptibility/resistance of each isolate to three first line and six second line anti-TB agents, using two different critical concentrations (CC) for each antibiotic.
Results: Agreement between susceptibility profiles and operational characteristics of diagnostic test yielded high performance and strong agreement with rifampicin 1μg/ml (agreement percent 90%, Kappa value 0.80) and amikacin 1μg/ml (agreement percent 96%, Kappa value 0.81), moderate for isoniazid 0.4μg/ml (agreement percent 89.4%, Kappa value 0.78), moxifloxacin at both CC’s 0.5μg/ml and 0.25μg/ml (agreement percent 93 and kappa values 0.73 for both), levofloxacin 2μg/ml (agreement 93%, kappa 0.69) and amikacin 2μg/ml (agreement 96%, Kappa 0.81), minimal for levofloxacin at CC 1.5μg/ml (agreement 90%, kappa 0.57) kanamycin at both CC’s 10μg/ml and 5μg/ml (agreement 87%, kappa 0.52) and ethionamide 5μg/ml (agreement 89%, kappa 0.46), weak for PAS 10μg/ml (agreement percent 93.9, kappa value 0.29), and none for ethambutol (Kappa value 0.02 for CC 10μg/ml, 0.07 for CC 5μg/ml). Conclusions: MODS+ assay is a cost-effective option for the diagnosis of TB and MDR/XDRTB, specially, in low resource settings with high TB incidence. Further operational research using lower CC’s, results read on different days and placed in settings with high and low TB and MDR/XDRTB burden could offer better sensitivities and wider applicability of results.
