Resistance patterns among multidrug-resistant tuberculosis patients in greater metropolitan Mumbai: trends over time.

BACKGROUND:While the high burden of multidrug-resistant tuberculosis (MDR-TB) itself is a matter of great concern, the emergence and rise of advanced forms of drug-resistance such as extensively drug-resistant TB (XDR-TB) and extremely drug-resistant TB (XXDR-TB) is more troubling. The aim of this study was to investigate the trends over time of patterns of drug resistance in a sample of MDR-TB patients in greater metropolitan Mumbai, India. METHODS:This was a retrospective, observational study of drug susceptibility testing (DST) results among MDR-TB patients from eight health care facilities in greater Mumbai between 2005 and 2013. We classified resistance patterns into four categories: MDR-TB, pre-XDR-TB, XDR-TB and XXDR-TB. RESULTS:A total of 340 MDR-TB patients were included in the study. Pre-XDR-TB was the most common form of drug-resistant TB observed overall in this Mumbai population at 56.8% compared to 29.4% for MDR-TB. The proportion of patients with MDR-TB was 39.4% in the period 2005-2007 and 27.8% in 2011-2013, while the proportion of those with XDR-TB and XXDR-TB was changed from 6.1% and 0% respectively to 10.6% and 5.6% during the same time period. During the same periods, the proportions of patients with ofloxacin, moxifloxacin and ethionamide resistance significantly increased from 57.6% to 75.3%, from 60.0% to 69.5% and from 24.2% to 52.5% respectively (p<0.05). DISCUSSION:The observed trends in TB drug-resistance patterns in Mumbai highlight the need for individualized drug regimens, designed on the basis of DST results involving first- and second-line anti-TB drugs and treatment history of the patient. A drug-resistant TB case-finding strategy based on molecular techniques that identify only rifampicin resistance will lead to initiation of suboptimal treatment regimens for a significant number of patients, which may in turn contribute to amplification of resistance and transmission of strains with increasingly advanced resistance within the community

Resistance patterns among MDR-TB patients diagnosed among 8 facilities in greater metropolitan Mumbai, 2005–2013.

<p>Resistance patterns among MDR-TB patients diagnosed among 8 facilities in greater metropolitan Mumbai, 2005–2013.</p

Additional resistance to first and second-line anti-TB drugs among MDR-TB patients in greater metropolitan Mumbai, 2005–2013.

<p>* Resistance to rifampicin and isoniazid only, Ofx-ofloxacin, Mfx-Moxifloxacin, Km-kanamycin, Am-Amikacin, Cm-capreomycin, Eto-ethionamide.</p><p>Additional resistance to first and second-line anti-TB drugs among MDR-TB patients in greater metropolitan Mumbai, 2005–2013.</p

Trends over time of resistance patterns among DR-TB patients diagnosed in 8 facilities in greater metropolitan Mumbai, 2005–2013

<p>Trends over time of resistance patterns among DR-TB patients diagnosed in 8 facilities in greater metropolitan Mumbai, 2005–2013</p

Resistance profile (first and second-line anti-TB drugs) for MDR-TB patients in greater metropolitan Mumbai, 2005–2013.

<p>S-streptomycin, H-isoniazid, R-rifampicin, E-ethambutol, Z- Pyrazinamide, Ofx-ofloxacin, Mfx-Moxifloxacin, Km-kanamycin, Am-Amikacin, Cm-capreomycin, Eto-ethionamide, Cfz- Clofazimine, PAS- para-aminosalicylic acid</p><p>*Linear-by-linear association chi-square test, p value<0.05.</p><p>Resistance profile (first and second-line anti-TB drugs) for MDR-TB patients in greater metropolitan Mumbai, 2005–2013.</p