Fenotipska karakterizacija biofilma bakterije Cutibacterium acnes iz okuženih ortopedskih vsadkov

Černe, Matej (author), Jeverica, Samo (mentor)

Izolati Cutibacterium acnes osamljeni iz okužb ortopedskih vsadkov (OOV) lahko predstavljajo povzročitelja okužbe ali kontaminacijo. Poleg kliničnih kriterijev pri interpretaciji rezultatov kultur uporabljamo tudi mikrobiološke kriterije. Naš cilj je bil izmeriti in primerjati tvorbo biofilma in vitro pri izolatih C. acnes iz OOV. Izbor kliničnih izolatov C. acnes (n=54) smo razdelili v dve skupini na podlagi mikrobioloških kriterijev (visoka oz. nizka verjetnost okužbe) in testirali z optimiziranim testom mikrotitrske ploščice (MTP). Za dokaz biofilma smo uporabili barvanje z 0,5 % kristal vijoličnim, ki smo ga ekstrahirali s 30 % ocetno kislino in merjenje absorbance ekstrakta pri 590 nm. Najvišje absorbance vzorcev smo izmerili pri 48h inkubaciji v fiziološki raztopini z 1 % glukozo (revni medij) in aerobnih pogojih. Vsak sev smo testirali v treh neodvisnih MTP, na vsaki po 4 vdolbinice. Povprečna vrednost absorbance vseh izolatov C. acnes je bila 0,164 (območje: 0,066-0,510, SD: 0,102). Po odšteti neg. kontroli (0,060) je bila porazdelitev absorbance sledeča: 76 % (<0,1), 10 % (0,1-0,2), 6 % (0,2-0,3), 4 % (0,3-0,4) in 6 % (>0,4). V skupini z visokim tveganjem okužbe je bila absorbanca 0,074, v skupini z nizkim tveganjem pa 0,134 (p=0,052). Sposobnost tvorbe biofilma je lahko eden izmed virulentnih dejavnikov bakterij pri razvoju OOV in dodatni kazalnik klinične pomembnosti osamljenega izolata C. acnes pri pacentih z OOV.

• Language: Slovenian
• Keywords: Cutibacterium acnes, biofilm, okužbe ortopedskih vsadkov, mikrotitrska ploščica
• Work type: Master's thesis/paper
• Typology: 2.09 - Master's Thesis
• Organization: BF - Biotechnical Faculty
• Publisher: [M. Černe]
• Year: 2019
• PID: 20.500.12556/RUL-107719
• UDC: 579.61:602:579.23(043.2)
• COBISS.SI-ID: 9235065
• Publication date in RUL: 17.05.2019

Secondary language

• Language: English
• Title: Phenotypic Characterization of Cutibacterum acnes Isolated from Infected Orthopedic Implants

Abstract

Cutibacterium acnes isolates from implant-associated infections (IAI) may represent either a causative agent of infection or a simple contaminant. Besides clinical criteria, several microbiological parameters can be used to guide the interpretation of positive C. acnes culture results. We aimed to measure and compare in-vitro biofilm production among different clinical isolates of C. acnes from IAIs. Selection of clinical C. acnes isolates (n=54), representing Slovenian cohort, and divided into 2 groups based on microbiological criteria (high vs. low probability of infection), were tested with optimized microtiter plate (MTP) assay. Each strain was tested in quadruplicates on three different MTPs. They were stained with 0,5 % crystal violet which was extracted with 30 % acetic acid and absorbance was measured at 590 nm. Maximum absorbance of isolates was obtained after 48h of incubation in saline supplemented with 1 % glucose (poor medium) and aerobic environment. Mean absorbance among all C. acnes isolates (n=54) was 0,164 O.D. (range: 0,066-0,510 O.D., SD: 0,102 O.D.). After subtracted neg. control (0,060) distribution of isolates based on the absorbance ranges was as follows: 76 % (<0,1), 10 % (0,1-0,2), 6 % (0,2-0,3), 4 % (0,3-0,4), 6 % (>0,4). Mean absorbance was 0.074 O.D. in the low-probability group and 0.134 O.D. in the high-probability group (p<0.052). Biofilm formation capacity may be one of the bacterial virulence factors predisposing the development of IAIs and may be used as an additional marker to asses significance of C. acnes in patients with IAIs.

• Keywords: Cutibacterium acnes, Biofilm, Prosthetic Joint Infections, Microtiter Plate