Diagnosis of orthopaedic-implant-associated infections caused by slow-growing Gram-positive anaerobic bacteria – a clinical perspective

Abstract

Abstract. Slow-growing Gram-positive anaerobic bacteria (SGAB) such as Cutibacterium acnes are increasingly recognized as causative agents of implant-associated infections (IAIs) in orthopaedic surgeries. SGAB IAIs are difficult to diagnose because of their non-specific clinical and laboratory findings as well as the fastidious growth conditions required by these bacteria. A high degree of clinical suspicion and awareness of the various available diagnostic methods is therefore important. This review gives an overview of the current knowledge regarding SGAB IAI, providing details about clinical features and available diagnostic methodologies. In recent years, new methods for the diagnosis of IAI were developed, but there is limited knowledge about their usefulness in SGAB IAI. Further studies are required to determine the ideal diagnostic methodology to identify these infections so that they are not overlooked and mistakenly classified as aseptic failure.

Amplicon-Based Next-Generation Sequencing as a Diagnostic Tool for the Detection of Phylotypes of Cutibacterium acnes in Orthopedic Implant-Associated Infections

“…Cutibacterium acnes ( C. acnes , formerly known as Propionibacterium acnes ) is a slow-growing Gram-positive anaerobic bacterium (SGAB) that is found preferentially in the pilosebaceous glands of the human skin ( McDowell et al, 2013 ; Aubin et al, 2014 ). It is increasingly being reported from various implant-associated infections, including orthopedic implant-associated infections (OIAI; Portillo et al, 2013 ; Achermann et al, 2014 ; Aubin et al, 2014 ; Ponraj et al, 2021 ). It is most frequently isolated from prosthetic joint infections (PJI) of the shoulder, but has also been implicated in OIAI of spine, hip, knee, elbow, and other joints ( Sampedro et al, 2009 ; Bacle et al, 2017 ; Renz et al, 2018a ; Namdari et al, 2019 ).…”

Inflammatory response in confirmed non-diabetic foot and ankle infections: A case series with normal inflammatory markers

“…Serum IL-6 has been described as a more sensitive marker of acute periprosthetic infection particularly in hips and knees with high accuracy, sensitivity, and specificity (97%, 100% and 95% respectively) but has not been specifically investigated in foot and ankle infections[ 34 - 36 ]. Measurement of bacterial load with a critical level of bacteria ≥ 10 4 to 10 6 colony-forming units per g of tissue has been also described to objectively confirm an infective aetiology[ 37 , 38 ].…”

Shotgun sequencing of sonication fluid for the diagnosis of orthopaedic implant-associated infections with Cutibacterium acnes as suspected causative agent

“…Cutibacterium acnes (formerly known as Propionibacterium acnes ) is a Gram-positive slow-growing anaerobic bacterium (SGAB). It is a skin commensal that has also been implicated in various implant-associated infections, including orthopaedic implant-associated infections (OIAIs) ( Zeller et al., 2007 ; McDowell et al., 2013 ; Achermann et al., 2014 ; Aubin et al., 2014 ; Ponraj et al., 2021 ). However, the diagnosis of OIAIs caused by SGAB such as C. acnes is complicated because of non-specific or even absent clinical, radiological, histopathological, and laboratory diagnostic features ( Achermann et al., 2014 ; Aubin et al., 2014 ; Ponraj et al., 2021 ).…”

“…It is a skin commensal that has also been implicated in various implant-associated infections, including orthopaedic implant-associated infections (OIAIs) ( Zeller et al., 2007 ; McDowell et al., 2013 ; Achermann et al., 2014 ; Aubin et al., 2014 ; Ponraj et al., 2021 ). However, the diagnosis of OIAIs caused by SGAB such as C. acnes is complicated because of non-specific or even absent clinical, radiological, histopathological, and laboratory diagnostic features ( Achermann et al., 2014 ; Aubin et al., 2014 ; Ponraj et al., 2021 ). Microbiological diagnosis based on culture can also be constrained by the need for prolonged incubation, due to the bacterium’s slow-growing nature, along with the attendant increased risk of sample contamination ( Butler-Wu et al., 2011 ).…”

“…Culture-independent methods can potentially help to offset this problem ( Gu et al., 2019 ). Culture-independent microbiological methods contain polymerase chain reaction (PCR)-based methods and sequencing-based methods; the latter comprise amplicon-based next-generation sequencing (aNGS) and metagenomic NGS (mNGS) ( Tande and Patel, 2014 ; Ponraj et al., 2021 ). The utility of mNGS in the diagnosis of OIAIs from various specimens including synovial fluid aspirates and tissue samples has been reported previously ( Ivy et al., 2018 ; Weaver et al., 2019 ; Cai et al., 2020 ; Fang et al., 2020 ; Huang et al., 2020 ; Kildow et al., 2021 ; Tan et al., 2022 ).…”