Correlation of Multidrug-Resistant Bacterial Infections with Histopathological Severity in Chronic Osteomyelitis

Abstract

Objective: This study aimed to assess the microbiological profile of chronic osteomyelitis (COM) and also to check the correlation between the severity of bone tissue and the presence of multidrug-resistant (MDR) bacterial infection.

Material and Methods: A prospective observational study was done in 150 patients who were diagnosed with COM clinically and radiologically over a 24-month period. Bone biopsy and sequestrectomy specimens were cultured, Bone biopsy and sequestrectomy specimens were cultured, identified by Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS), and antimicrobial susceptibility testing (AST) was performed according to the Clinical and Laboratory Standards Institute (CLSI) guidelines. A modified histopathological severity scoring system (necrosis, inflammatory infiltrate, fibrosis, osteoblastic activity, and new bone formation) was used. Data was analyzed statistically using Chi square test, Mann Whitney U test and Spearman's correlation test.

Results: Among the 128 culture-positive cases, 84 (65.6%) were infected with MDR organisms, mainly MRSA (32.1%) and ESBL-producing enterobacteria (28.5%). The mean of the histopathological severity score was significantly elevated in the MDR group (14.2 ± 1.8) than in the non-MDR group (11.2 ± 2.8) (p < 0.001). Severe bone necrosis was also strongly correlated with MDR infections (r = 0.68, p < 0.001), as well as dense fibrotic replacement (r = 0.72, p < 0.001).

Conclusion: The association between MDR bacterial infection and higher histopathologic severity of chronic osteomyelitis with high bone necrosis and fibrosis score is significant. Combining microbiological AST and histopathological grading offers a holistic perspective on disease severity and helps to inform aggressive surgical and antimicrobial therapy.