Identification and Antimicrobial Susceptibility Testing of Anaerobic Bacteria: Rubik’s Cube of Clinical Microbiology?

Abstract

Anaerobic bacteria have pivotal roles in the microbiota of humans and they are significant infectious agents involved in many pathological processes, both in immunocompetent and immunocompromised individuals. Their isolation, cultivation and correct identification differs significantly from the workup of aerobic species, although the use of new technologies (e.g., matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, whole genome sequencing) changed anaerobic diagnostics dramatically. In the past, antimicrobial susceptibility of these microorganisms showed predictable patterns and empirical therapy could be safely administered but recently a steady and clear increase in the resistance for several important drugs (β-lactams, clindamycin) has been observed worldwide. For this reason, antimicrobial susceptibility testing of anaerobic isolates for surveillance purposes or otherwise is of paramount importance but the availability of these testing methods is usually limited. In this present review, our aim was to give an overview of the methods currently available for the identification (using phenotypic characteristics, biochemical testing, gas-liquid chromatography, MALDI-TOF MS and WGS) and antimicrobial susceptibility testing (agar dilution, broth microdilution, disk diffusion, gradient tests, automated systems, phenotypic and molecular resistance detection techniques) of anaerobes, when should these methods be used and what are the recent developments in resistance patterns of anaerobic bacteria.

First Case of Intracranial Mycotic Aneurysm Caused by <b><i>Prevotella intermedia</i></b> Associated with Chronic Sinusitis in a Korean Adult

“…When grown only in liquid medium, the bacteria should be subcultured on solid medium to obtain pure single colonies. Obligate anaerobes including Prevotella species do not tolerate oxygen exposure [13]; therefore, culturing them on solid medium requires strict conditions, and obtaining single colonies is difficult. In this case, red growth was detected only in thioglycolate broth.…”

Standardization of the Safety Level of the Use of DMSO in Viability Assays in Bacterial Cells

“…It is an easyto-perform and economical technique developed by the European Committee for Antimicrobial Susceptibility Testing (EUCAST), its standardized methods and clinical breakpoints have been adopted by clinical microbiology laboratories in Europe as well as in other parts of the globe [10].…”

Dissecting the collateral damage of antibiotics on gut microbes

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