Abstract
BACKGROUND: Listeriosis, caused by Listeria monocytogenes (L. monocytogenes), is a severe infectious disease with high hospitalization and fatality rates. Urgent epidemiological studies on this disease with geographic variability are needed, particularly in developing countries. METHODS: This study included non-perinatal patients with listeriosis from four tertiary centers in Shandong, China. Data on demographics, clinical characteristics, and outcomes were collected retrospectively over 8 years (2015-2022). RESULTS: Among 292,254 non-perinatal patients, 27 listeriosis cases were identified, resulting in an incidence of nine cases per 100,000 admissions. Patients had a median age of 56 years, with 66.7% having comorbidities. Fever was the most common symptom (88.9%), and 44.4% had central nervous system involvement. Most patients (26/24; 96.3%) received antibiotics, 37.0% received monotherapy and 59.3% combination therapy. The mortality rate was 22.2%. The antimicrobial susceptibility test showed that 25 strains were sensitive to most antibiotics. Multilocus sequence typing revealed nine sequence types (ST), predominantly ST8 (44.4%), and serogroup 1/2a is the most common serogroup (66.7%). CONCLUSIONS: This study provides valuable insights into the clinical and molecular features of L. monocytogenes in non-perinatal patients with listeriosis. The findings demonstrated the predominance of serogroup 1/2a and ST8. Despite low resistance and appropriate treatment, listeriosis remains associated with a significant mortality rate, emphasizing the need for timely diagnosis and effective management strategies.