Osteomyelitis of the Hip due to Granulicatella adiacens: A Case Report of an Extremely Rare Cause of Bone Infection.

BACKGROUND

Granulicatella adiacens (G. adiacens) is a nutritionally variant Streptococcus generally observed in the human mouth microbiota. Although G. adiacens is involved in bacterial endocarditis and bacteremia, bone and joint infections are extremely rare. In the present study, we reported the first known case of hip osteomyelitis related to G. adiacens. Moreover, a commentary on the available evidence was also performed.

CASE PRESENTATION: A 59-year-old male with a former substance use disorder who initially complained of low back pain with a medical history negative for any other comorbidities, albeit absence seizures. After an accurate evaluation, hip osteomyelitis caused by G. adiacens was diagnosed. In our patient, neither bacteremia nor infectious endocarditis was reported, as well as previous oral surgery. The diagnosis of G. adiacens was performed through 16S rRNA gene sequencing. A three-stage surgery was performed based on surgical debridement and antibiotic-cemented spacer implant, antibiotic-cemented spacer renewal, spacer removal, and prosthesis implantation. Throughout the entire period, the patient received antibiotic therapy with doxycycline and cotrimoxazole. At the final follow-up, the patient was infection-free, but a poor hip function was reported.

CONCLUSION

G. adiacens is rarely associated with bone osteomyelitis, probably because of the difficulty in culture isolation that might lead to misdiagnosis, especially in cases of polymicrobial infection. In our experience, debridement, prolonged antibiotics, and two-stage/three- stage prosthesis implantation could be considered as a treatment strategy for hip osteomyelitis involving G. adiacens.