What has likely contributed to the increased resistance of Mycobacterium tuberculosis to streptomycin?

The increased resistance of Mycobacterium tuberculosis to streptomycin can be attributed largely to the increasing use of this antibiotic for treating bacterial infections. When an antibiotic like streptomycin is frequently used, particularly inappropriately or without adequate oversight, it can lead to selective pressure on bacterial populations. This means that any strains of Mycobacterium tuberculosis that have or acquire mutations conferring resistance to the antibiotic are more likely to survive and reproduce. Over time, these resistant strains can become more prevalent in the population, leading to a higher overall resistance to streptomycin.

This phenomenon is compounded in environments where antibiotic use is widespread or where treatment regimens are not strictly followed, which can further encourage the development of resistance. As resistant strains proliferate, they can make treatment more difficult and less effective, necessitating the use of alternative and often more costly therapies.