Ureaplasma parvum causes hyperammonemia in a pharmacologically immunocompromised murine model.

A relationship between hyperammonemia and Ureaplasma infection has been shown in lung transplant recipients. We have demonstrated that Ureaplasma urealyticum causes hyperammonemia in a novel immunocompromised murine model. Herein, we determined whether Ureaplasma parvum can do the same. Male C3H mice were given mycophenolate mofetil, tacrolimus, and prednisone for 7 days, and then challenged with U. parvum intratracheally (IT) and/or intraperitoneally (IP), while continuing immunosuppression over 6 days. Plasma ammonia concentrations were determined and compared using Wilcoxon rank-sum tests. Plasma ammonia concentrations of immunosuppressed mice challenged IT/IP with spent broth (median, 188 μmol/L; range, 102-340 μmol/L) were similar to those of normal (median, 226 μmol/L; range, 154-284 μmol/L, p > 0.05), uninfected immunosuppressed (median, 231 μmol/L; range, 122-340 μmol/L, p > 0.05), and U. parvum IT/IP challenged immunocompetent (median, 226 μmol/L; range, 130-330 μmol/L, p > 0.05) mice. Immunosuppressed mice challenged with U. parvum IT/IP (median 343 μmol/L; range 136-1,000 μmol/L) or IP (median 307 μmol/L; range 132-692 μmol/L) had higher plasma ammonia concentrations than those challenged IT/IP with spent broth (p < 0.001). U. parvum can cause hyperammonemia in pharmacologically immunocompromised mice.