Osteomyelitis caused by Veillonella species: Case report and review of the literature.

Previously, Veillonella species had been considered as nonpathogenic and rarely caused serious infections. We report a case of 25-year-old man with osteomyelitis caused by Veillonella species. He was admitted to the hospital due to an open fracture to the left radial bone caused by industrial washing machine accident, and emergency surgery was performed. However, wound infections occurred one week after the operation. Although Acinetobacter baumannii and Serratia marcescens were cultured from the pus, obligate anaerobic bacteria were not detected at that point. Debridement was repeated and antibiotics were changed according to the result of bacterial culture and drug sensitivity. Despite this, the infection was poorly controlled. On the 5th debridement, granulomatous bone tissues on pseudarthrosis were found for the first time at the infection site. Although no bacteria was detected with aerobic culture, anaerobic incubation revealed Gram-negative cocci which was later identified as Veillonella species by 16S rRNA gene sequence analysis. His condition improved without any additional debridement after adding effective antibiotics against Veillonella species. It is well known that prolonged infection with aerobes consumes oxygen in the infection site and leads the environment to more favorable conditions for anaerobic bacteria, thus we speculated that prolonged infection with bacteria such as S. marcescens induced the favorable environment for Veillonella species. Physicians should realize the importance of anaerobic culture method in routine practice, especially in complicated cases such as the present case. In this article, we reviewed case reports of Veillonella infection and summarized the clinical features of this organism.