Distinct clinical profiles of nongonococcal gram-negative septic arthritis: a retrospective analysis from a tertiary center

BACKGROUND: Septic arthritis is life-threatening, with gram-positive bacteria as the primary cause. However, gram-negative infections are more prevalent in Asia, often resulting in inadequate empirical therapy and higher mortality. The factors linked to gram-negative septic arthritis remain poorly understood. Our aim was to investigate the prevalence, clinical characteristics, and predictive factors of nongonococcal gram-negative septic arthritis in the northeastern region of Thailand. METHODS: We conducted a retrospective study by analyzing medical records from Srinagarind Hospital, a 1,500-bed university hospital in northeastern Thailand, covering the period from January 1, 2015, to October 24, 2024. RESULTS: A total of 194 patients were included, of whom 67 (34.5%) were infected with gram-negative bacteria. The most common causative agent was Burkholderia pseudomallei (11.3%), followed by Escherichia coli (7.2%). Patients with gram-negative septic arthritis had a greater risk of requiring intensive care unit (ICU) or semi-ICU admission. Multivariate analysis revealed that diabetes mellitus, pyuria, and the absence of bacteria on synovial fluid Gram-stain were significant risk factors for gram-negative septic arthritis. In contrast, hypertension and upper joint involvement were associated with septic arthritis caused by gram-positive bacteria. Additionally, we observed that gram-negative-infected patients were more likely to receive ineffective empirical antibiotics. CONCLUSIONS: This study revealed a greater prevalence of nongonococcal gram-negative septic arthritis in the northeastern region of Thailand. Several risk factors, along with distinct clinical and laboratory characteristics, have been identified, which may help guide the selection of empiric antibiotics for more effective treatment. CLINICAL TRIALS REGISTRY: Retrospectively registered at Thai Clinical Trials Registry. The study was reviewed and approved on 13/02/2025. TCTR identification number is TCTR20250213003.