Background
Periprosthetic joint infection is a serious complication after total joint arthroplasty and polymicrobial PJI which compose a subtype of PJI often indicate worse outcomes compared to monomicrobial periprosthetic joint infection. However, a literature review suggested that there were limited number studies evaluating the risk factors of polymicrobial PJI.
Materials and methods
Between 2015 January and 2019 December, a total of 64 polymicrobial PJI patients and 158 monomicrobial PJI patients in a tertiary center were included in this study and corresponding medical records were scrutinized. The diagnosis of PJI was based on 2014 MSIS criteria. Logistic regression was used to identify the association between various variables and polymicrobial PJI and ROC curve was used to identify their efficiency.
Results
The prevalence of polymicrobial PJI is about 28.28% in our cohorts. After adjusting, the presence of previous revisions (OR, 1.93; p < 0.01), isolation of enterococci (OR, 11.36; p < 0.01), isolation of Escherichia coli (OR, 6.55; p < 0.01), infection with atypical organisms (OR, 9.85; p < 0.01), infection with gram-negative organisms (OR, 6.33; p < 0.01), isolation of streptococcus spp (OR, 1.93; p < 0.01), and infection with CNS (OR, 1.93; p < 0.01) were risk factors of polymicrobial PJI compared to monomicrobial PJI. However, knee infection is a protection factor of polymicrobial PJI with an adjusted OR=0.0479 (p=0.023).
Conclusion
This study demonstrated that the prevalence of polymicrobial PJI is about 28.28% in culture-positive PJI patients. Moreover, the presence of sinus tract and previous joint revisions were risk factors for identifying different bacterial species in the intraoperative specimens. Therefore, in these PJI cases, it is necessary to examine multiple specimens of both intraoperative tissue and synovial fluid for increasing the detection rate and obtaining resistance information.