A rare case of disseminated Mycoplasma pneumoniae infection spreading from a pelvic lesion to a psoas muscle abscess.

OBJECTIVES

Extrapulmonary infections caused by Mycoplasma pneumoniae are uncommon, and their manifestation as soft tissue abscesses is particularly rare. Diagnosing such culture-negative infections in immunocompromised hosts poses a significant clinical challenge. This study reports a case of M. pneumoniae-induced soft tissue abscesses in an immunocompromised patient, highlighting the diagnostic utility of advanced microbiological techniques.

METHODS

We retrospectively analyzed the clinical course of a 17-year-old female with aplastic anemia and a history of haploidentical hematopoietic stem cell transplantation, who presented with recurrent fever and pelvic/psoas abscesses. Metagenomic next-generation sequencing (mNGS) was performed on abscess drainage to identify the causative pathogen and its resistance profile.

RESULTS

mNGS of the abscess fluid identified M. pneumoniae as the dominant pathogen and revealed a macrolide-resistant 23S rRNA A2063G mutation. Consequently, targeted antimicrobial therapy with tigecycline and omadacycline was administered, which led to the resolution of clinical symptoms.

CONCLUSION

This case underscores the critical role of mNGS in the accurate diagnosis of culture-negative extrapulmonary infections. Furthermore, it demonstrates how mNGS-guided resistance profiling can inform effective antimicrobial therapy in immunocompromised patients.