Mycoplasma hominis as Cause of Extragenital Infection in Patients with Hypogammaglobulinemia: Report of 2 Cases and Literature Review

Mycoplasma hominis can be a part of human urogenital tract microbiome, and it is a frequent cause of urogenital infections. In rare cases, it can also cause extragenital infections, especially in immunocompromised patients. In this case series, we report two cases and provide a literature review of extragenital infections caused by M. hominis in patients with hypogammaglobulinemia. Patient 1 was a 61-year-old woman with diffuse large B-cell lymphoma who, after rituximab-containing chemotherapy and CAR-T therapy, developed M. hominis spondylodiscitis. Patient 2 was a 50-year-old woman with congenital hypogammaglobulinemia who developed disseminated M. hominis infection involving pleura, muscles, and right ankle. Antibiotic therapy with levofloxacin and doxycycline for 10 weeks in patient 1 and with levofloxacin alone for 6 weeks in patient 2 led to infection resolution. The literature review identified 14 additional cases reporting M. hominis extragenital infection in patients with hypogammaglobulinemia. M. hominis should also be suspected as an etiological agent of extragenital infection in patients with B-cell immunodeficiency with a clinical picture of persistent, standard-culture negative infection, particularly with arthritis or abscess formation. Even if M. hominis can grow on standard bacterial medium, in suspected cases molecular methods should be promptly used for correct diagnostic work-up and successful therapy.