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Mycobacterium smegmatis infection of a prosthetic total knee arthroplasty
1McLaren Macomb Hospital, Department of Internal Medicine, 1000 Harrington Blvd., Mount Clemens, MI 48043, United States.
Abstract:
The most common organisms causing prosthetic knee joint infections are staphylococci. However, arthroplasty infections with atypical microbial pathogens, such as Mycobacteria can occur. Due to the rarity of mycobacterial prosthetic joint infections, diagnosis, treatment, and management of these atypical infections represent a clinical challenge. A 71-year old female post-operative day 40 after a left total knee arthroplasty was hospitalized secondary to left knee pain and suspected arthroplasty infection. She had failed outpatient oral antimicrobial treatment for superficial stitch abscess; and outpatient IV/Oral antimicrobials for a clinical postoperative septic bursitis. Ultimately, resection arthroplasty with operative tissue acid fast bacterial cultures demonstrated growth of the Mycobacterium smegmatis group. Post-operatively, she completed a combination course of oral doxycycline and levofloxacin and successfully completed a replacement arthroplasty with clinical and microbial resolution of the infection. To our knowledge, literature review demonstrates three case of knee arthroplasty infection caused by the Mycobacterium smegmatis group. Correspondingly, optimal surgical procedures and antimicrobial management including antimicrobial selection, treatment duration are not well defined. Presently, the best treatment options consists of two step surgical management including prosthesis hardware removal followed by extended antimicrobial therapy, followed by consideration for re-implantation arthroplasty. Our case illustrates importance of considering atypical mycobacterial infections in post-operative arthroplasty infections not responding to traditional surgical manipulations and antimicrobials. For an arthroplasty infection involving the atypical Mycobacterium smegmatis group, two step arthroplasty revision, including arthroplasty resection, with a combination of oral doxycycline and levofloxacin can lead to successful infection resolution, allowing for a successful replacement arthroplasty.
Insights
Prosthetic knee infections can be caused by atypical bacteria like Mycobacterium smegmatis. This case highlights successful treatment using two-stage surgery and antibiotics, emphasizing the need to consider unusual pathogens.
Area of Science:
- Orthopedic Surgery
- Infectious Diseases
- Microbiology
Background:
- Staphylococci are common causes of prosthetic knee joint infections.
- Atypical pathogens, such as Mycobacteria, can also cause these infections, posing diagnostic and management challenges due to their rarity.
Purpose of the Study:
- To report a case of prosthetic knee joint infection caused by the Mycobacterium smegmatis group.
- To discuss the diagnostic and treatment challenges associated with atypical mycobacterial arthroplasty infections.
- To highlight a successful treatment strategy involving two-stage surgery and specific antimicrobial therapy.
Main Methods:
- A 71-year-old female patient with suspected prosthetic knee infection underwent resection arthroplasty.
- Operative tissue cultures identified the Mycobacterium smegmatis group.
- Post-operative treatment included oral doxycycline and levofloxacin, followed by a replacement arthroplasty.
Main Results:
- The patient achieved clinical and microbial resolution of the infection.
- Literature review identified only three previously reported cases of knee arthroplasty infection by the Mycobacterium smegmatis group.
- The described treatment approach led to a successful outcome, allowing for subsequent re-implantation arthroplasty.
Conclusions:
- Atypical mycobacterial infections should be considered in prosthetic joint infections that do not respond to standard treatments.
- A two-stage surgical approach combined with extended antimicrobial therapy (doxycycline and levofloxacin) can be effective for Mycobacterium smegmatis group infections.
- Further research is needed to establish optimal surgical and antimicrobial management protocols for these rare infections.
