Classical and New Assays for Detecting Drug Resistance in Tuberculosis

Abstract

Tuberculosis is a public health concern worldwide. Particularly worrying is the emergence of severe forms of drug resistance, such as extensively drug resistant and totally drug resistant tuberculosis, with few treatment options for the afflicted patients. To avoid further spread of drug resistance, its early detection is extremely important. Conventional phenotypic procedures to detect drug resistance depended on the in vitro slow growth of the bacteria. More recent molecular approaches such as reverse-hybridization assays and real-time PCR tests have been introduced. Newer options proposed include, faster culture-based methods and whole-genome sequencing and nanotechnology. Not yet available is a real point-of-care test, applied directly in clinical samples and reliable enough for guiding a treatment option.

Revisiting the methods for detecting Mycobacterium tuberculosis: what has the new millennium brought thus far?

“…In the early 1990s, a pioneer NAAT study was conducted by Eisenach and colleagues [ 77 ] to detect M. tuberculosis using PCR, in which sensitivity, specificity and concluding results were available within 48 h. This method can also be employed to identify drug-resistant bacilli ( Table 2 ). In fact, a broad review on the topic of drug sensitivity testing was performed in 2014 [ 78 ], and thus we intended to update this subject ( Table 3 ). Accordingly, we conducted a phenotypic and genetic analysis of a drug-resistant phenotype and resistance-conferring mutations in patients at a referral hospital in Fortaleza, Brazil [ 79 ].…”

Prevalence of Mycobacterium tuberculosis mutations associated with isoniazid and rifampicin resistance: A systematic review and meta-analysis

“…However, achieving appropriate treatment outcomes with these drugs may not be successful given the emergence of drug-resistant strains. Drug resistance is a major cause of treatment failure in TB, especially when the strains become resistant to the primary drugs such as INH and RIF, which lead to the development of MDR-TB [17] , [22] , [23] . Generally, resistance to INH is more prevalent than that to RIF.…”

Epidemiologia global de pacientes com tuberculose multidrogarresistente (MDR-TB) e extensivamente resistente (XDR-TB)

“…Embora confiável este teste possui uma grande desvantagem: o tempo de 4 a 6 semanas de incubação para um resultado fidedigno. Os métodos de cultura líquida, lançado nos anos 1980, sendo este o BACTEC MGIT960 (Becton Dickinson, Sparks, MD, EUA), são bem mais rápidos detectando a resistência em 5 a 9 dias 13 .…”