Genetic Variation in Mycoplasma genitalium

Abstract

Mycoplasma genitalium (MG) is the smallest self-replicating bacterium. Although small in size, unique MG genome induces distinctive and often serious characteristics in the infected cells. Due to its small genome and chronic symptomatic characteristics in the infected host, it first appears as a weak, insignificant, and easily controllable microbe. However, it is not a monotonous chrysalis, but rather a multicolored butterfly with various capabilities. Repetitive DNA sequence in MG's immunodominant MgPa operon has been considered as an efficient strategy to evade the host immune surveillance and mediate MG's genetic flexibility. Because of MG's pathogenicity in multiple organs, various antimicrobials are prescribed, further exerting selection pressure on microbes. Consequently, a rapidly increasing drug resistance in macrolide and moxifloxacin has been frequently reported globally, radically decreasing the overall cure rate of infection. Re-infection can be defined as a new MG infection through antigenic variation, while persistent infection refers to recurrent infections caused by the same MG isolate through acquisition of antimicrobial resistance. Therefore, we must differentiate between re-infection and persistent MG infection, and approach them accordingly. The genetic mechanisms of DNA variation in the MgPa operon and antibiotic resistance must be considered for the management of multicolored infection. In this respect, the unique genetic characteristics of MG will be described in detail. We hope that with this manuscript, clinicians can expand their understanding of recurrent MG infections and better choose an appropriate treatment for the infection in clinical setting.