Related Experiment Video
Updated: Jun 23, 2026
Novel Diagnostics in Revision Arthroplasty: Implant Sonication and Multiplex Polymerase Chain Reaction
Published on: December 3, 2017
[Two cases of septic arthritis by Mycoplasma hominis after total knee replacement arthroplasty]
Ji Hyun Lee1, Jang Ho Lee, Nam Yong Lee
1Department of Laboratory Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Gangnam-gu, Seoul, Korea.
Abstract:
Mycoplasma hominis has been related with pelvic inflammatory illnesses and postpartum and neonatal infections. Extragenital M. hominis infections are rare, but septicemia, septic arthritis, wound infection, meningitis, and other infections in Immunocompromised patients have also been described. Here we report two cases of septic arthritis caused by M. hominis in patients following total knee replacement arthroplasty. After the surgery, the patients presented with knee pain and clinical signs of infection, such as fever, erythema and swelling on the surgical site. Arthroscopic debridement operations were performed on the surgical site. M. hominis was isolated from the joint fluid and identified by the microscopic visualization of the typical "fried-egg-type" colonies on Mycoplasma specific agar (pleuropneumonia-like organism agar). It was also confirmed by 16S rRNA sequencing. To the best of our knowledge, this is the first report of prosthetic joint infections with M. hominis in Korea.
Insights
Mycoplasma hominis can cause rare infections after knee replacement surgery. This report details two cases of septic arthritis due to M. hominis following total knee arthroplasty.
Area of Science:
- Infectious Diseases
- Orthopedic Surgery
- Microbiology
Background:
- Mycoplasma hominis is associated with pelvic inflammatory and postpartum infections.
- Extragenital Mycoplasma hominis infections are uncommon but documented in immunocompromised individuals.
Observation:
- Two patients developed septic arthritis after total knee replacement arthroplasty.
- Clinical signs included knee pain, fever, and erythema at the surgical site.
Findings:
- Mycoplasma hominis was identified in joint fluid from both patients.
- Diagnosis was confirmed by characteristic "fried-egg" colonies on specific agar and 16S rRNA sequencing.
- This represents the first reported cases of prosthetic joint infection by M. hominis in Korea.
Implications:
- Highlights the potential for Mycoplasma hominis to cause prosthetic joint infections.
- Emphasizes the importance of considering Mycoplasma in post-arthroplasty infections.
- Contributes to the understanding of extragenital Mycoplasma hominis infections.