Hyperammonemia syndrome associated with Ureaplasma spp. Infections in immunocompromised patients and transplant recipients: A systematic review and meta-analysis

Background: Hyperammonemia syndrome (HS) is reported to occur in patients with Ureaplasma spp. infections. We performed a systematic review and meta-analysis of studies reporting HS in patients with Ureaplasma spp. infection. Methods: We searched several databases (CINAHL, OVID, ProQuest, and Scopus) from inception to January 2021. We described case reports and series, and performed a meta-analysis for all cohort studies. The pooled risk ratio (RR) for the association between HS and Ureaplasma spp. infections was derived using a random-effects model. Results: The systematic review yielded 18 studies. HS was reported in 53 patients with Ureaplasma spp. infections. The most common clinical manifestations were neurologic. Meta-analysis showed a higher incidence of HS (41.67%) and peak ammonia concentration among Ureaplasma spp.–infected lung transplant recipients compared with Ureaplasma spp.–negative recipients (2.84%). The risk of HS was significantly increased in Ureaplasma spp.–infected recipients compared with Ureaplasma spp.–negative recipients (RR: 14.64; CI: 2.85–75.24). Mortality from Ureaplasma-associated HS was 27.27% compared with 5.24% in those with HS from other causes. Conclusions: The risk of developing HS is higher among Ureaplasma-infected patients compared with uninfected patients. Lung transplant recipients appear to be disproportionally affected, and HS should be suspected in those who present with neurologic symptoms.