Objective  To explore the clinical characteristics and risk factors of macrolide resistance Moraxella catarrhalis (MRMC) pneumonia.

  Methods  From January 2013 to January 2022, the information of 32 patients with MRMC pneumonia and 114 patients with macrolides sensitive Moraxella catarrhalis (MSMC) pneumonia were retrospectively analyzed.

  Results  The patients with Moraxella catarrhalis pneumonia were mainly men (71.92%) and aged ≥65 years (67.12%). The incidence rate was high in winter and spring (64.38%). Multivariate logistic regression analysis showed that being woman (OR=2.77, 95% CI: 1.18–6.47) and the history of tuberculosis (OR=5.95, 95% CI: 1.31–31.57) were independent risk factors for MRMC pneumonia. The percentage of patients with fever (OR=2.87, 95% CI: 1.09–7.46), abnormal C-reactive protein (OR=2.65, 95% CI: 1.12–6.63), bronchitis (OR=4.00, 95% CI: 1.54–11.52), and emphysema (OR=5.73, 95% CI: 1.94–19.56) increased significantly in the MRMC group compared with the MSMC group.

  Conclusion  Being woman and the history of tuberculosis were independent risk factors for MRMC pneumonia, and patients in the MRMC group had more severe symptoms, inflammation and pulmonary imaging manifestations, suggesting that attention should be paid to the clinical diagnosis and treatment of MRMC pneumonia.