Activity of linezolid-containing regimens against multidrug-resistant tuberculosis in mice

The objective of the present study was to compare the activities of regimens containing linezolid (LZD) with those not containing LZD against Mycobacterium tuberculosis infection in mice. The three regimens excluding LZD selected in this study are often used in practice against multidrug-resistant tuberculosis (MDR-TB). When LZD was added to these MDR-TB regimens, the combinations were significantly more active after 2 months of therapy with regard to lung CFU reductions. The activity of LZD-containing regimens was greater than the World Health Organization's standard first-line regimen of rifampicin+isoniazid+pyrazinamide. In particular, when LZD was included in the combination levofloxacin+amikacin+para-aminosalicylic acid+pyrazinamide+clofazimine, culture negativity of the lungs was reached after 2 months of treatment in every case. In addition, the serum levels of interleukin-10 and interferon-γ of mice were determined and were found not to be surrogate markers of bacterial clearance.