C. avidum is an uncommon cause of PJI. Yet in one matched cohort of culture-positive hip PJIs, it was found in 22.2% of infections after direct anterior THA, compared with 2.8% after a lateral approach (Aichmair, 2022). C. avidum is also found particularly often in the groin, close to the anterior operative field (Böni, 2018).
Summary
C. avidum was much more common among culture-positive hip PJIs after direct anterior than lateral THA in one matched cohort, although overall PJI incidence was not significantly higher with the anterior approach.
Around the hip, C. avidum was found most often in the groin rather than at the anterior thigh, and groin colonisation was associated with higher BMI.
The groin sits close to the anterior operative field and may act as a reservoir, but C. avidum hip PJI also occurs after other approaches and in patients without obesity.
PJI incidence and organism profile
For a relatively uncommon organism, 22.2% versus 2.8% stands out. The matched analysis included 36 culture-positive hip PJIs after direct anterior THA and 36 after lateral THA (Aichmair, 2022). Patients were matched for age, sex, BMI, polymicrobial infection rate and measures of comorbidity and surgical-site infection risk (Aichmair, 2022).
The 22.2% figure refers to the organism profile within established PJI. C. avidum accounted for 8 of 36 culture-positive hip PJIs after direct anterior THA, compared with 1 of 36 after lateral THA. It is not the infection rate after anterior THA (Aichmair, 2022).
A 2025 meta-analysis of 11 studies and more than 44,000 THAs found no significant difference in overall PJI incidence between direct anterior and other approaches. Evidence for differences in the organisms causing those infections was much more limited (Hantouly, 2025).
C. avidum in the groin
Earlier series had already linked C. avidum mainly to the hip. Of 13 C. avidum PJIs, 11 involved the hip (Achermann, 2018). Obesity was common too: 9 of the 12 patients with detailed clinical data had a BMI above 30 kg/m² (Achermann, 2018). All four hip PJIs identified prospectively in 2015 followed primary arthroplasty through an anterior approach (Achermann, 2018).
If C. acnes is associated with sebaceous skin and shoulder infection, C. avidum seems much more at home in moist areas such as the groin (Böni, 2018; Moore, 2021).
Skin samples from 65 patients awaiting primary hip arthroplasty allowed the three areas to be compared directly. Before surgical disinfection, samples were taken from the groin, the anterior thigh over the tensor fascia lata, and the lateral thigh at the level of the greater trochanter (Böni, 2018).
C. avidum was recovered from the groin in 24.6% of patients. At the anterior thigh it was found in 7.7%, and at the lateral thigh in 9.2% (Böni, 2018).
Groin colonisation was more common with higher BMI. Patients colonised with C. avidum had a median BMI of 30.1 kg/m², compared with 25.6 kg/m² in those without it, and the odds of groin colonisation increased with BMI (Böni, 2018). The association was with groin colonisation, not directly with PJI.
C. acnes resides mainly in pilosebaceous glands and is common in sebaceous skin, including the face, scalp, chest and back (Moore, 2021). C. avidum is associated with sweat glands and moist areas such as the axilla and groin (Böni, 2018).
The anterior incision and the groin
The highest C. avidum colonisation was not at the anterior incision site, but in the nearby groin. The anterior sample was taken over the tensor fascia lata, while the groin sample lay further medially between the pubic symphysis and anterior superior iliac spine (Böni, 2018).
The direct anterior incision therefore lies closer to the heavily colonised groin than a lateral incision does. If the groin acts as a reservoir, it is nearby rather than directly underneath the incision.
None of these studies links an individual PJI directly to groin colonisation. The skin data show where C. avidum commonly lives, while the clinical studies show where it has appeared in PJI. They do not demonstrate the path from one to the other (Böni, 2018).
C. avidum without an anterior approach
If that were the whole explanation, C. avidum hip PJI would be expected mainly after anterior surgery and mainly in patients with obesity.
A 2024 series from one centre described four patients with C. avidum hip PJI over 30 months (Karlsson, 2024). Three primary arthroplasties had been performed through an anterolateral approach and one through a posterior approach. None used the direct anterior approach. Only one of the four patients was obese (Karlsson, 2024).
Whole-genome sequencing showed that the four isolates were genetically distinct, arguing against a common-source outbreak (Karlsson, 2024). That does not establish where each infection came from, but it makes a single shared strain much less likely.
Four cases are far too few to challenge the earlier association. They do show that C. avidum hip PJI can occur without obesity or a direct anterior approach.
Closing note
Skin microbiology has an anatomy. C. acnes and C. avidum favour different parts of the skin, and the location of those habitats may influence which organisms appear in implant infection.
An anterior incision sits closer to the groin, where C. avidum is common. That may affect which organism causes an infection, even if the overall risk of PJI is similar.
References
Achermann Y, Liu J, Zbinden R, et al. Propionibacterium avidum: A Virulent Pathogen Causing Hip Periprosthetic Joint Infection. Clinical Infectious Diseases. 2018;66(1):54–63.
Aichmair A, Frank BJH, Singer G, et al. Differential microbiological spectrum and resistance pattern in periprosthetic hip joint infections: a matched cohort analysis comparing direct anterior versus lateral approach. BMC Musculoskeletal Disorders. 2022;23:72.
Böni L, Kuster SP, Bartik B, et al. Association of Cutibacterium avidum Colonization in the Groin With Obesity: A Potential Risk Factor for Hip Periprosthetic Joint Infection. Clinical Infectious Diseases. 2018;67(12):1878–1882.
Hantouly AT, Muthu S, Lawand J, et al. The impact of surgical approach in total hip arthroplasty on the organisms profile of periprosthetic joint infections? A systematic review and meta-analysis. Archives of Orthopaedic and Trauma Surgery. 2025;145:293.
Karlsson J, Kamenska N, Matuschek E, Brüggemann H, Söderquist B. Cutibacterium avidum: A Potent and Underestimated Pathogen in Prosthetic Hip Joint Infections. Microorganisms. 2024;12(3):432.
Moore NFE, Batten TJ, Hutton CEJ, White WJ, Smith CD. The management of the shoulder skin microbiome (Cutibacterium acnes) in the context of shoulder surgery: a review of the current literature. Shoulder & Elbow. 2021;13(6):592–599.