Tiny but Nasty: A Case Report and a Review of the Literature on Ureaplasma Parvum Peritonitis

Ureaplasma parvum, a member of the Mollicutes class, is a rare but significant pathogen in extragenital infections. This case report is the tenth known case of Ureaplasma spp. peritonitis, occurring in a 36-year-old female post extensive surgery for metastatic sigmoid colon adenocarcinoma. Following the intervention, the patient exhibited post-surgical peritonitis with fever despite empirical broad-spectrum antibiotics. Conventional bacterial and fungal cultures remained negative, prompting the use of 16 S rRNA polymerase chain reaction (PCR) for diagnosis. Ureaplasma parvum was detected in both peritoneal and perihepatic fluid samples, and in the urine, leading to the initiation of doxycycline therapy. The patient responded positively to the treatment, with complete resolution of symptoms and no recurrence observed during a four-year follow-up. This report underscores the clinical challenge posed by Ureaplasma spp. due to its resistance to common antibiotics and difficulty in cultivation. It highlights the importance of molecular diagnostics in identifying such pathogens in culture-negative cases and the necessity of considering Ureaplasma spp. especially in female patients with persistent peritonitis post-urogenital procedures or surgeries. The case also reflects on the limited data regarding antimicrobial susceptibility, emphasizing the need for tailored therapeutic approaches based on local resistance patterns and the clinical context. Ultimately, this case contributes valuable insights into the diagnosis and management of Ureaplasma spp. peritonitis, advocating for heightened clinical suspicion and appropriate molecular testing to ensure effective patient outcomes.