Active surveillance and antimicrobial prophylaxis to prevent hyperammonemia syndrome in lung transplant recipients: A...

Hyperammonemia syndrome (HS) is a life-threatening complication primarily affecting lung transplant recipients (LTR). HS is strongly associated with mollicute infection. We implemented an active surveillance and prophylaxis protocol for HS in LTR. Herein, we evaluate the impact of our protocol on rates and outcomes of HS.

This was a single-center retrospective cohort study of adult LTR performed from 1/1/2019 to 6/6/2024. Our surveillance and prophylaxis protocol was implemented on 8/1/2022 and included PCR testing for mollicutes on post-operative bronchoalveolar lavage samples, measurement of serum ammonia levels, and azithromycin prophylaxis. Comparisons between pre- and post-protocol implementation groups were performed.

151 patients received a lung transplant during the study period, 54 (35.8%) following protocol implementation. Mollicute testing was performed in 57 LTR with most tests sent after protocol implementation (87.0% vs 10.3%, p<0.0001). Ammonia levels were checked in 53.7%; however, only 24.1% had levels checked by post-operative day 3. Ten LTR (6.6%) were diagnosed with mollicute infection, six in the pre-protocol and four in the post-protocol arm, with 70% of infections due to Mycoplasma spp. All LTR received antimicrobial prophylaxis following protocol implementation. Pre-protocol, 3.1% of LTR were diagnosed with definite HS compared to 0% in the post-protocol arm, despite 4 patients being diagnosed with mollicute infection.

Implementing a mollicute screening and prophylaxis protocol reduced cases of HS in LTR despite some LTR developing mollicute infection. Antimicrobial prophylaxis with azithromycin and doxycycline may further optimize LTR prophylaxis. Larger studies are needed to determine optimal screening and prophylaxis strategies for HS in LTR.