Rapid detection of Mycobacterium tuberculosis based on antigen 85B via real-time recombinase polymerase amplification
LETTERS IN APPLIED MICROBIOLOGY
Authors: Xu, Y.; Wu, P.; Zhang, H.; Li, J.
Abstract
Tuberculosis (TB), as a common infectious disease, still remains a severe challenge to public health. Due to the unsatisfied clinical needs of currently available diagnostic vehicles, it is desired to establish a new approach for universally detecting Mycobacterium tuberculosis. Herein, we designed a real-time recombinase polymerase amplification (RPA) technology for identifying M. tuberculosis within 20 min at 39 degrees C via custom-designed oligonucleotide primers and probe, which could specifically target antigen 85B (Ag85B). Particularly, the primers F4-R4 produced the fastest fluorescence signal with the probe among four pairs of designed primers in the RPA assays. The optimal primers/probe combination could effectively identify M. tuberculosis with the detection limit of 4 center dot 0 copies per mu l, as it could not show a positive signal for the genomic DNA from other mycobacteria or pathogens. The Ag85B-based RPA could determine the genomic DNA extracted from M. tuberculosis with high reliability (100%, 22/22). More importantly, when testing clinical sputum samples, the real-time RPA displayed an admirable sensitivity (90%, 95% CI: 80 center dot 0-96 center dot 0%) and specificity (98%, 95% CI: 89 center dot 0-100 center dot 0%) compared to traditional smear microscopy, which was similar to the assay of Xpert MTB/RIF. This real-time RPA based Ag85B provides a promising strategy for the rapid and universal diagnosis of TB.
What are the origins of growing microbial resistance? Both Lamarck and Darwin were right
EXPERT REVIEW OF ANTI-INFECTIVE THERAPY
Authors: Guevara Salazar, Juan Alberto; Moran Diaz, Jessica Rubi; Ramirez Segura, Enrique; Trujillo Ferrara, Jose Guadalupe
Abstract
Introduction Microorganisms of clinical importance frequently develop resistance to drug therapy, now a growing problem. The experience with Mycobacterium tuberculosis is a representative example of increasing multi-drug resistance. To avoid reaching a crisis in which patients could be left without adequate treatment, a new strategy is needed. Anti-microbial therapy has historically targeted the mechanisms rather than origin of drug resistance, thus allowing microorganisms to adapt and survive. Areas covered This contribution analyses the historical development (1943-2020) of the evolution of multi-drug resistance by M. tuberculosis strains in light of Darwin's and Lamarck's theories of evolution. Expert opinion Regarding the molecular origin of microbial drug resistance, genetic mutations and epigenetic modifications are known to participate. The analysis of the history of drug resistance by M. tuberculosis evidences a gradual development of resistance to some antibiotics, undoubtedly due to random mutations together with natural selection based on environmental pressures (e.g., antibiotics), representing Darwin's idea. More rapid adaptation of M. tuberculosis to new antibiotic treatments has also occurred, probably because of heritable acquired characteristics, evidencing Lamarck's proposal. Therefore, microbial infections should be treated with an antibiotic producing null or low mutagenic activity along with a resistance inhibitor, preferably in a single medication.