Genotypic and Phenotypic Characteristics of Staphylococcus aureus Prosthetic Joint Infections: Insight on the Pathogenesis and Prognosis of a Multicenter Prospective Cohort

Abstract

Background Staphylococcus aureus is the leading cause of prosthetic joint infection (PJI). Beyond the antibiogram, little attention has been given to the influence of deep microbiological characteristics on patient’s prognosis. Our aim was to investigate whether microbiological genotypic and phenotypic features have a significant influence on infection pathogenesis and patient outcome. Methods prospective multicentre study was performed, including all S. aureus PJIs (2016-2017). Clinical data, phenotypic (agr functionality, β-hemolysis, biofilm formation) and genotypic characteristics of the strains were collected. Biofilm susceptibility to antimicrobials was investigated (MBEC assay). Results 88 patients (39.8% men, age 74.7±14.1 years) were included. Forty-five had early post-operative (EPI), 21 chronic (CPI), and 19 hematogenous infections (HI). Twenty (22.7%) were caused by MRSA. High genotypic diversity was observed, including 16 clonal complexes (CC), CC5 being the most frequent (30.7%). agr activity was greater in EPI than CPI (55.6% vs 28.6%, p=0.041). Strains causing EPI were phenotypically and genotypically similar, regardless of symptom duration. Treatment failure (36.5%) occurred less frequently among cases treated with implant removal. In cases treated with debridement and implant retention, there were fewer failures among those who received combination therapy with rifampin. No genotypic or phenotypic characteristics predicted failure, except vancomycin MIC>=1.5 mg/L (23.1% failure vs 3.4%, p=0.044). MBEC50 was >128 mg/L for all antibiotics tested and showed no association with prognosis. Conclusions S. aureus with different genotypic backgrounds is capable of causing PJI, showing slight differences in clinical presentation and pathogenesis. No major microbiological characteristics were observed to influence the outcome, including MBEC.

Comparative Phenotypic and Genomic Features of Staphylococci from Sonication Fluid of Orthopedic Implant-Associated Infections with Poor Outcome

“…In the current study, all S. aureus isolates were MRSA and belonged to CC5. The prospective cohort study published by Muñoz-Gallego et al [33] shows a high frequency of MRSA, with 80% CC5 in PJI associated with treatment failure. In fact, MRSA isolates of hospital origin belonging to CC5 and CC8 are closed related, and spreads globally including within Latin American countries [17,34,35].…”

Microbiological and Molecular Features Associated with Persistent and Relapsing Staphylococcus aureus Prosthetic Joint Infection

“…Our group recently conducted a prospective, multicenter, observational study of 88 cases of PJI caused by S. aureus [ 18 ]. Most patients were treated with DAIR (debridement < 21 days after symptom onset) and received antibiotic treatment according to the antimicrobial susceptibility profile.…”

“…Biofilm formation was assessed in triplicate by the 0.7% crystal violet method on microtiter plates using 33% glacial acetic acid as the decolorizing solution [ 18 ]. Absorbance was measured at 595 nm.…”

“…Previous studies have focused on analyzing the clinical characteristics of the Staphylococcal–PJI evolution [ 4 , 15 ], but few have delved into the study of the microbiological characteristics and molecular factors that influence PJI development [ 16 , 17 , 18 ]. We hypothesized that some clinical isolates of S. aureus exhibit certain phenotypic and genotypic characteristics that eventually favor persistent or relapsing PJIs.…”

To DAIR or not to DAIR: Decision-making in the management of acute prosthetic joint infection � A narrative review

“…In addition, it is possible that the chronology of infection, including both the age of the prosthesis and duration of symptoms, may have a differential influence on outcome, depending on the specific etiology, and furthermore on the specific bacterial strain, its virulence factors, and ability to form a mature biofilm 63 . Other variables, such as the activity of the antimicrobial treatment used, could also modify the importance of time.…”