Unit:
Faculty of MedicineLibrary of the School of Health Sciences
Dissertation committee:
Σπυρίδων Πνευματικός Καθηγητής, Ιατρική Σχολή ΕΚΠΑ, Επιβλέπων
Σοφία Χατζηιωάννου, Καθηγήτρια, Ιατρική Σχολή, ΕΚΠΑ
Νικόλαος Σύψας, Καθηγητής, Ιατρική Σχολή, ΕΚΠΑ
Ευστάθιος Χρονόπουλος, Αναπληρωτής Καθηγητής, Ιατρική Σχολή, ΕΚΠΑ
Ιωάννης Βλάμης, Επίκουρος Καθηγητής, Ιατρική Σχολή, ΕΚΠΑ
Βασίλειος Κοντογεωργάκος, Επίκουρος Καθηγητής, Ιατρική Σχολή, ΕΚΠΑ
Βασίλειος Νικολάου, Επίκουρος Καθηγητής, Ιατρική Σχολή, ΕΚΠΑ
Original Title:
Συγκριτική μελέτη ετερογένειας αντοχής μικροβιακών πληθυσμών σε ιστικές καλλιέργειες και καλλιέργειες υγρού υπερήχων σε ορθοπαιδικά εμφυτεύματα
Translated title:
A comparative study of heterogeneous antibiotic resistance of microbial populations in conventional periprosthetic tissue cultures and sonication fluid cultures of orthopaedics explanted prostheses
Summary:
PJI is one of the most demanding complications in reconstructive hip and knee surgery. Accurate microbiological diagnosis of periprosthetic infections is critical because decisively influences the direction of treatment (antibacterial treatment and surgical rehabilitation) and the course of surgery. Additionally, non-diagnosed cases of periprosthetic infection may mistakenly be seen as cases of aseptic loosening with consequent inaccurate treatment for the patient. The identification and susceptibility testing of bacteria that caused the infection helps in granting targeted and not empirical antimicrobial therapy.
Our study aimed to investigate the change in the resistance of microbes isolated after PJI, as well as the correlation of microbial resistance to standard antimicrobial antibiotics.
In our study we enrolled patients undergoing revision hip or, knee arthroplasty, internal fixation because of loosening of the prostheses or because of periprothetic joint infection. All patients had periprosthetic tissue culture, sonication of prosthesis and direct inoculation of SF into blood culture bottles. We calculated the sensitivity, specificity, positive predictive value, and negative predictive value of each method separately as well as their combination.
The findings of our study are summarized as follows: Between May 2014 and June 2019, we investigated 234 patients, 111 (47.4%) were men and 123 (52.6%) were women, with a mean age of 65 years (19 to 95 years). Using standard non-microbiological criteria to determine PJI, it was found that 143 patient (61.1%) had aseptic loosening while 91 patients (38.9%) had PJI.
Comparing the two methods, the results of our study showed that the method of sonication was significantly more sensitive than tissue culture ([91% (83-96) vs 43% (33-54); p <0.005]) but comparable to specificity. [100% (97-100) vs 100% (97-100), p = NS]. In a fifty-two (52) patients out of ninety-one (91) the diagnosis of periprosthetic infection was performed only by the method of sonication as no bacteria were detected by the conventional method of culturing the periprosthetic tissue. In our study, S. epidermidis was the most commonly isolated strain followed by S. aureus, at a rate of 35.2% and 19.8%, respectively.
In this study, heterogeneity was reported in 15 cases. This figure represents 16.5% of all infections (91 records) and 6.4% in the total population (243 participants). Antibiotics in which the microorganisms exhibited heterogeneous bacterial behavior were Gendamicin (ν=14) Tigecycline (ν=14), Ciprofolxacin ( ν=14 ) , Moxifloxacin ( ν=14 ),Trimethop(ν=13) Vancomycin ( ν=13),Teicoplanin ( ν=13 ) , Oxacillin( ν=12 ) , Rifampicin ( ν=12 ) Clindamycin( ν=11 ) , Erythromycin ( ν=11 ) , Linezolid ( ν=11 ) και Tetracycline ( ν=11 ).
There is increasing evidence that heterogeneity can lead to therapeutic failure and that the detection of this phenotype is a prerequisite for a proper antibiotic choice to have a successful therapeutic effect.
The proper application of the ultrasound methodology is a prerequisite for successful use in microbiological diagnostics of implant infections. The ability of the method to detect heterogeneity resistance of microbial populations may reduce the therapeutic failures of the administered antimicrobial treatment.
Main subject category:
Health Sciences
Keywords:
Prosthetic joint infection, Sonication fluid, Diagnosis, Heterogeneity
Number of references:
166
File:
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ΔΙΔΑΚΤΟΡΙΚΗ ΔΙΑΤΡΙΒΗ Α. ΜΠΑΝΟΥΣΗ.pdf
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