Clinical analysis of hospital acquired mycoplasma pneumoniae infection after cardiac surgery: a case series.

Background: Methods: Using inpatient data of Guangdong Provincial People's Hospital, we conducted a retrospective case series study of hospital-acquired MP infection after cardiac surgery from January 2015 to December 2020 to investigate the clinical characteristics. Clinical data was extracted from patients with a confirmed diagnosis of MP infection after >48 hours of hospitalization. All analyses for this study were descriptive. Data were expressed as mean ± standard deviation (SD), median with range or number with percentage as appropriate. Results: We totally included 22 patients. The time of onset of hospital-acquired MP infection after surgery was 23.32±12.57 days, and the duration of antibiotic use before the onset of infection was 4-40 days. Both fever and sore throat were the main symptoms of nosocomial MP infection, and the rash was the most common physical sign. Laboratory tests were normal for peripheral blood leukocyte count and procalcitonin in most patients (17 cases), while the lymphocyte count was decreased in 10 cases. A single serum anti-MP antibody titer ≥1:160 combined with clinical manifestations and imaging helped confirm nosocomial MP infection, although a double serum anti-MP antibody (four-fold change in titer) wasn't seen. With quinolone therapy, such as levofloxacin, all the patients' temperature gradually returned to normal and were discharged uneventfully. Conclusions: Patients after cardiac surgery should be aware of the presence of hospital-acquired MP infection when they develop new fever accompanied by atypical bacterial infection signs such as sore throat and rash during treatment. In such cases, changes in MP antibody titers need to be monitored and anti-MP therapy is required.