TABLE 2.
Organism | No. of positive results in patients with PJI or AF bya: |
|||||
---|---|---|---|---|---|---|
PCR-ESI/MS (at any level of detection) |
Synovial fluid culture |
|||||
PJI | AF | Total | PJI | AF | Total | |
Coagulase-negative Staphylococcus spp. | 8 | 3e | 11b | 10 | 0 | 10 |
Staphylococcus aureus | 4 | 1e | 5 | 4 | 0 | 4 |
Viridans group Streptococcus species | 1c | 0 | 1 | 1 | 0 | 1 |
Propionibacterium acnes | 0 | 1 | 1 | 0 | 0 | 0 |
Methylobacterium mesophilium | 0 | 1e | 1 | 0 | 0 | 0 |
Micrococcus lylae/luteus | 0 | 2e | 2 | 0 | 0 | 0 |
Capnocytophaga canimorsus | 1 | 0 | 1 | 1 | 0 | 1 |
Candida albicans | 1 | 0 | 1 | 1 | 0 | 1 |
Enterococcus faecalis | 1 | 0 | 1 | 1 | 0 | 1 |
Polymicrobial | 1d | 2d,e | 3 | 0 | 0 | 0 |
PJI, prosthetic joint infection; AF, aseptic failure.
The 11 positive results were broken down as follows: Staphylococcus epidermidis (7 positive results), Staphylococcus epidermidis/caprae (1 positive result), Staphylococcus capitis (1 positive result), Staphylococcus warneri (1 positive result), and Staphylococcus haemolyticus (1 positive result). Six (all S. epidermidis) were mecA positive.
Streptococcus salivarius/thermophilus.
Polymicrobial detections by PCR-ESI/MS included Propionibacterium acnes plus Candida tropicalis (PJI subject), P. acnes plus Streptococcus salivarius species group plus Streptococcus mitis species group (AF subject), and Enterobacter cloacae complex plus Acinetobacter baumannii (AF subject).
The PCR-ESI/MS result was positive but below the 24-GE/well level of detection for Staphylococcus haemolyticus (1 result), Staphylococcous aureus (1 result), Methylobacterium mesophilium (1 result), and Micrococcus lylae/luteus (2 results) and in both polymicrobial cases (except for Propionibacterium acnes).