Microbial sensor for drug susceptibility testing ofMycobacterium tuberculosis

Abstract

Aims: Drug susceptibility testing (DST) of clinical isolates of Mycobacterium tuberculosis is critical in treating tuberculosis. We demonstrate the possibility of using a microbial sensor to perform DST of M. tuberculosis and shorten the time required for DST. Methods and Results:The sensor is made of an oxygen electrode with M. tuberculosis cells attached to its surface. This sensor monitors the residual oxygen consumption of M. tuberculosis cells after treatment with anti-TB drugs with glycerine as a carbon source. In principle, after drug pretreatment for 4-5 days, the response differences between the sensors made of drug-sensitive isolates are distinguishable from the sensors made of drug-resistant isolates. The susceptibility of the M. tuberculosis H37Ra strain, its mutants and 35 clinical isolates to six common anti-TB drugs: rifampicin, isoniazid, streptomycin, ethambutol, levofloxacin and para-aminosalicylic acid were tested using the proposed method. The results agreed well with the gold standard method (LJ) and were determined in significantly less time. The whole procedure takes approximately 11 days and therefore has the potential to inform clinical decisions. Conclusions: To our knowledge, this is the first study that demonstrates the possible application of a dissolved oxygen electrode-based microbial sensor in M. tuberculosis drug resistance testing. This study used the microbial sensor to perform DST of M. tuberculosis and shorten the time required for DST. Significance and Impact of the Study: The overall detection result of the microbial sensor agreed well with that of the conventional LJ proportion method and takes less time than the existing phenotypic methods. In future studies, we will build an O 2 electrode array microbial sensor reactor to enable a high-throughput drug resistance analysis.

Ensemble density-dependent synchronization of mycobacterial growth: BACTEC MGIT 960 fluorescence-based analysis and mathematical modelling of coupled biophysical and chemical processes

“…One of the most reliable processes for such studies is the bacterial respiration. The search for methods, which correlate the oxygen content in a medium, where bacteria grow, and characteristics of their vital activity was started at the dawn of quantitative experimental microbiology [6] and is continuing up to present, including such modern challenges as studying drug susceptibility and resistance [7] . Such an approach is based on two reasons: i) Oxygen consumption by breathing is a direct marker of different metabolic processes in living and dividing bacteria [8] , [9] ; ii) a dynamical change of the concentration of oxygen dissolved in a liquid medium can be accurately and effectively detected, registered and quantified by methods of analytical chemistry.…”