Les Staphylocoques à coagulase négative (SCN) et leur formation de biofilm sur les biomatériaux

Abstract

Coagulase-negative staphylococci (SCN), which are normal components of human skin and mucous microflora, are the most frequently isolated species from medical device-related infections (ILDM).Their main virulence factor is their ability to adhere to the surface of biomaterials and form a biofilm. With this in mind, the present work focuses on a microbiological study of 12 medical devices DM (urinary catheter, orotracheal intubator probe, peripheral catheter, dressing, and bone fixation steel plate) harvested from different departments of the Chéguivara hospital in Mostaganem) to identify the pathogens responsible for infections, to determine their antimicrobial resistance profile and their ability to produce the slime. The diagnosis reveals that of 12 samples analyzed, 66.66% were positive, of which 75% are the SCN involved, with a predominance of S. epidermidis.# The antimicrobial resistance study showed significant resistance to beta-lactam (Oxacillin OX and cefoxitin FOX) reaching 100% for all isolated strains. And Vancomycin VA remains the molecule of choice against Staphylococcal infections. The detection of slime production by the three TCP, TM, and CRA techniques reveals that the TM and TCP methods seem more reliable than the Congo red, whose tube technique has a good correlation with the tissue culture plate technique. For high biofilm producing strains. The large capacity of the S. epidermidis strain adherence originated from a bladder probes placed more than 7 days, confirms that the implantation time plays a key role in the installation of biofilms, and consequently the latex probes can’t be maintained in the body for more than a week and the good visual diffusion of biofilm on blood agar for all our strains tested confirms probably their ability to adhere to the surface of LATEX: material constituting the urinary catheters.