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Published on: November 2, 2021
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Heterogeneous glycopeptide intermediate Staphylococcus epidermidis isolated from prosthetic joint infections
S Tevell1, C Claesson, B Hellmark
1Department of Infectious Diseases, Karlstad Hospital, Karlstad, Sweden, staffan.tevell@liv.se.
Summary
Heterogeneous vancomycin-intermediate Staphylococcus epidermidis (hGISE) is common in prosthetic joint infections (PJIs). Standard susceptibility testing may not detect hGISE, potentially leading to insufficient glycopeptide treatment for MRSE infections.
Area of Science:
- Microbiology
- Infectious Diseases
- Clinical Diagnostics
Background:
- Methicillin-resistant Staphylococcus epidermidis (MRSE) is a significant pathogen in prosthetic joint infections (PJIs).
- Vancomycin is a primary antibiotic choice for empirical treatment of staphylococcal PJIs.
- Emerging reports of heterogeneous glycopeptide intermediate Staphylococcus aureus (hGISA) necessitate investigation into similar resistance mechanisms in S. epidermidis.
Purpose of the Study:
- To determine the prevalence of heterogeneous glycopeptide intermediate Staphylococcus epidermidis (hGISE) in PJIs.
- To evaluate the effectiveness of standard antimicrobial susceptibility testing in detecting hGISE.
- To assess the implications of hGISE on glycopeptide treatment efficacy in PJIs.
Main Methods:
- Analysis of 122 S. epidermidis isolates from 119 patients undergoing revision surgery for PJIs in Sweden (1993-2012).
- Antimicrobial susceptibility testing against various antibiotics, including vancomycin and teicoplanin.
- Detection of hGISE using the macromethod Etest (MME) and glycopeptide resistance detection (GRD) Etest.
Main Results:
- No vancomycin-resistant S. epidermidis isolates were found; however, 11.5% exhibited teicoplanin resistance.
- hGISE was prevalent, detected in 77.9% of isolates.
- hGISE was identified even in isolates with teicoplanin Minimum Inhibitory Concentration (MIC) ≤2 mg/L, indicating limitations of standard MIC testing.
- Multidrug resistance was significantly higher in hGISE-positive isolates (90.5%) compared to hGISE-negative isolates (59.3%).
Conclusions:
- Heterogeneous glycopeptide intermediate S. epidermidis (hGISE) is a common finding in prosthetic joint infections.
- Standard laboratory diagnostic methods may fail to detect hGISE, complicating treatment decisions.
- Glycopeptide therapy may be inadequate for PJIs caused by hGISE-positive S. epidermidis, even when standard susceptibility tests indicate susceptibility.
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