Streptomycin is used in many countries to treat plague, but some strains of Y. Pestis show resistance to it. To study resistance, Dai and others examined 536 strains of the bacterium in vitro and also identified the genes responsible for this resistance (Dai et al., 2021). All procedures were carried out in accordance with the ethical standards of the National Research Committee. This experiment makes a significant contribution to the study of the problem of resistance of the bacterium responsible for the occurrence of plague, investing in the development of a more effective method of treatment.
Methods
536 Y. Pestis isolates identified during outbreaks in China were tested for antibiotic resistance. Y. Pestis susceptibility testing and associated quality control were based on standard methods from the Clinical and Laboratory Standards Institute. The agar dilution method was conducted to determine minimum inhibitory concentrations (Dai et al., 2021). All procedures were performed in a biosafety level 3 laboratory; PCR testing was performed using DNA polymerase.
Results
The clinical isolate of Y. Pestis showed the highest resistance to the antibiotic streptomycin. This strain was identified during the 1996 outbreak of pneumonic plague in the Tibet region (Dai et al., 2021). Previous experiments attributed bacterial resistance to antibiotics to the presence of conjugative plasmids (Dai et al., 2021). However, the high resistance is due to a mutation in the rpsL gene, that is, a ribosomal protein with amino acid substitution 43. These results are confirmed by previous experiments on the strain of Mycobacterium tuberculosis, which is also resistant to existing treatment. Plasmid-mediated resistance of bacterium isolates, as well as ribosomal protein mutation, should be taken into account if the treatment of plague with antibiotics is suspected to be ineffective (Dai et al., 2021). The identified resistance of Y. Pestis to streptomycin poses a threat to public health.
Reference
Dai, R., He, J., Zha, X., Wang, Y., Zhang, X., Gao, H., Yang, H., Li, J. Zhang, Q., Bai, J., Peng, Y., Wu, H., Zhang, Q., Wei, B., Xu, J., & Li, W. (2021). A novel mechanism of streptomycin resistance in Yersinia pestis: Mutation in the rpsL gene. PLoS neglected tropical diseases, 15(4), 1-10.