Higher accuracy of genotypic identification compared to phenotyping in the diagnosis of coagulase-negative staphylococcus infection in orthopedic surgery.

Autor: Muñoz-Gamito G; Hospital Universitari Mútua Terrassa, Terrassa, Spain.; Universitat Autònoma de Barcelona, Bellaterra, Spain., Cuchí E; Department of Clinical Microbiology, CATLAB, Terrassa, Spain., Roigé J; Department of Molecular Microbiology, CATLAB, Terrassa, Spain., Gómez L; Hospital Universitari Mútua Terrassa, Terrassa, Spain., Jaén À; Fundació per la Recerca Mútua Terrassa, Terrassa, Spain., Matamala A; Hospital Universitari Mútua Terrassa, Terrassa, Spain., Pedro-Botet ML; Universitat Autònoma de Barcelona, Bellaterra, Spain., Capdevila JA; Universitat Autònoma de Barcelona, Bellaterra, Spain.; Consorci Sanitari del Maresme, Mataro, Spain., Anglès F; Hospital Universitari Mútua Terrassa, Terrassa, Spain.; Universitat de Barcelona, Barcelona, Spain., Pérez J; Department of Molecular Microbiology, CATLAB, Terrassa, Spain.
Jazyk: angličtina
Zdroj: Infectious diseases (London, England) [Infect Dis (Lond)] 2020 Nov - Dec; Vol. 52 (12), pp. 883-890. Date of Electronic Publication: 2020 Jul 31.
DOI: 10.1080/23744235.2020.1799069
Abstrakt: Purpose: To determine whether Repetitive Extragenic Palindromic PCR (rep-PCR) genotyping can improve the diagnosis of coagulase-negative staphylococcal (CoNS) orthopaedic infections in comparison to phenotyping.
Methods: Prospective study comparing the results of phenotypic/genotypic (rep-PCR) testing in patients with suspected CoNS infection. Each strain was analysed using both methods. Strains identified as identical in ≥2 samples were considered as pathogenic.
Results: 255 CoNS strains from 52 surgical episodes were included. Infection was diagnosed by phenotyping in 38(73%) cases and by genotyping in 40(77%). The Kappa index was 0.59. Sensitivity, Specificity, Positive Predictive Value (PPV) and Negative Predictive Value (NPV) for phenotyping (vs. rep-PCR) were: 88%, 75%, 92%, and 64%. 5/14(36%) of cases not considered as true infections by phenotyping were diagnosed as infections with genotyping. In a subgroup of 203 strains from 41 surgical procedures with orthopaedic implants, the kappa index was 0.68. Sensitivity, Specificity, PPV, and NPV for phenotyping were: 93%, 73%, 90% and 80%. Again, 2/10 episodes in which CoNS were considered non-infective by phenotyping were diagnosed as infected by genotyping.
Conclusions: Rep-PCR genotyping can identify identical CoNS strains that differ in their phenotype and should be used as a complementary technique. One-third of infected cases may be misdiagnosed without genotypic analysis.
Databáze: MEDLINE
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