Rôle du laboratoire de biologie médicale dans le diagnostic microbiologique des bactéries anaérobies

Abstract

Role of medical biology laboratory in the microbiological diagnosis of anaerobic bacteriaThere is a renewed interest in the study of anaerobes bacteria because of their role in microbiota and in infectious processes. Various commercially available systems (transport media, solid culture media and broth, systems providing suitable anaerobic environment) allow to isolate anaerobic bacteria successfully from clinical specimens. The use of matrix-assisted laser desorption/ionization timeof-flight mass spectrometry, eventually supplemented by 16S rRNA gene sequencing, has revolutionized identification of anaerobes, with quickly and accurately results even for unusual anaerobes. Conventional phenotypic techniques based on routinely usable and cost-effective tests (microscopy, rapid biochemical tests and special potency antibiotic disks) lead to an identification of main clinically relevant anaerobes at the genus level and sometimes at the species level but is time consuming. Because significative change in resistance patterns of many anaerobes (Bacteroides, Parabacteroides, Prevotella, anaerobe Gram positif cocci), antimicrobial susceptibility testing (AST) is recommended, especially in the case of monomicrobial infections or mixed infections incriminating potentially resistant bacteria. Methodology for easy and flexible routine AST of anaerobic bacteria is essentially based to date on the use of gradient strips. Agar dilution, considered as the reference standard for AST remains reserved for specialized laboratories.