Case Presentation: Ureaplasma species are cell wall–deficient commensals of the urogenital tract, most commonly U. urealyticum and U. parvum (1). Their lack of a cell wall confers intrinsic resistance to β-lactam and glycopeptide antibiotics; effective classes include fluoroquinolones, tetracyclines, macrolides, and chloramphenicol (1). Although colonization occurs in up to 40–80 % of sexually active women without symptoms (2), invasive infections are described in immunocompromised hosts (3,4). Culture is slow and insensitive, whereas PCR offers superior sensitivity and faster detection (5).A 20-year-old woman with SLE (lupus nephritis, ITP) on obinutuzumab, mycophenolate, hydroxychloroquine and prednisone had four hospitalizations in the precedingm3 month period for sterile pyuria, recurrent cystitis, CMV cystitis, and sepsis due to urinary infections. After presenting to an outside hospital for urinary tract symptoms and started on empiric treatment for neutropenic fever, she was transferred to UCSD. On hospital day (HD) 20 she continued to have daily fevers (>103 °F), tachycardia, and enlarging bilateral renal abscesses despite escalation of antibiotic treatment to include meropenem and vancomycin. She underwent drainage of a renal abscess with Interventional radiology while cultures remained negative. Empiric doxycycline and fluconazole were eventually started on HD 24–25 for persistent sepsis and clinical instability as clinical suspicion for ureaplasma infection was high after review of literature, despite few case reports available. Fever curve and CRP finally improved after initiation of doxycycline. On HD 30, PCR of urine and drained abscess fluid finally returned positive for U. urealyticum, confirming the diagnosis. Given the patients slow improvement, and infectious disease recommendation favoring dual therapy given difficulty with resistance testing for ureaplasma, therapy was transitioned to levofloxacin plus azithromycin. Her fevers ultimately resolved, renal abscesses began to shrink. She was discharged four weeks later with prolonged oral therapy with interval MRI planned.
Discussion: Few reports describe Ureaplasma renal abscesses in adults, but several—Baker 2024, Ngoo 2020, Yazdani 2012, Poulsen 2023, Pallares 2020, Eilers 2007—implicate B-cell–depleting therapy (anti-CD20 monoclonals) or profound immunosuppression as predisposing factors. These cases share common features: culture-negative abscesses, delayed recognition, and clinical deterioration despite broad β-lactam therapy. Our patient mirrors these reports, underscoring two critical lessons: Diagnostic Vigilance: Recurrent sterile pyuria and negative cultures in immunocompromised patients warrant PCR for Ureaplasma or Mycoplasma, particularly in immunocompromised patients Therapeutic Precision: β-lactams are ineffective; doxycycline is first-line, but combination therapy (fluoroquinolone + macrolide) may be necessary.
Conclusions: This appears to be the first reported case of U. urealyticum causing pyelonephritis with extensive multifocal renal abscesses in the setting of obinutuzumab therapy for SLE/ITP. Recognition of the organism’s β-lactam resistance and prompt PCR testing are critical to avoid prolonged ineffective therapy and poor outcomes. Empiric tetracyclines or fluoroquinolones with appropriate testing should be considered for persistent sterile pyuria or abscesses in similar immunologic contexts.