Are conventional microbiological diagnostics sufficiently expedient in the era of rapid diagnostics? Evaluation of conventional microbiological diagnostics of orthopedic implant-associated infections (OIAI).

ABSTRACT

Background and purpose - In a time when rapid diagnostics are increasingly sought, conventional procedures for detection of microbes causing orthopedic implant-associated infections (OIAI) seem extensive and time-consuming, but how extensive are they? We assessed time to (a) pathogen identification, (b) antibiotic susceptibility patterns, and (c) targeted antibiotic treatment using conventional microbiological diagnostics of OIAI in a consecutive series of patients.Patients and methods - Consecutive patients aged ≥18 years undergoing first revision surgery for acute OIAI, including prosthetic joints, fracture, and osteotomy implants, in 2017-2018 at Akershus University Hospital (Ahus), Norway were included. Information regarding microbiological diagnostics and clinical data was collected retrospectively from the hospital's diagnostic and clinical databases.Results - 123 patients fulfilled the inclusion criteria. Median time to pathogen identification was 2.5 days and to antibiotic treatment recommendations was 3.5 days. The most common pathogens were S. aureus (52%) and S. epidermidis (15%). Cultures were inconclusive in 11% of the patients. Of the 109 patients with culture-positive results, antibiotic treatment was changed in 66 (61%) patients within a median of 4 days (0-24) after the recommendation was given.Interpretation - Conventional microbiological diagnostics of OIAI is time-consuming, taking days of culturing. Same-day diagnostics would vastly improve treatment efficacy, but is dependent on rapid implementation by clinicians of the treatment recommendations given by the microbiologist.