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

Gajdács, Márió; Spengler, Gabriella; Urbán, Edit

doi:10.3390/antibiotics6040025

Cited by 143 publications

(179 citation statements)

References 188 publications

(253 reference statements)

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“…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.…”

Section: Discussion/conclusionmentioning

confidence: 99%

First Case of Intracranial Mycotic Aneurysm Caused by Prevotella intermedia Associated with Chronic Sinusitis in a Korean Adult

et al. 2020

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Intracranial infection caused by anaerobic bacteria is rare, and it is difficult to identify absolute anaerobes in the clinical laboratory, especially when the bacterial load is low. Here, we report the first case of intracranial mycotic aneurysm caused by Prevotella intermedia associated with chronic sinusitis and successful identification of the bacteria by 16S rRNA sequencing from bacterial growth in broth only.

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Section: Discussion/conclusionmentioning

confidence: 99%

First Case of Intracranial Mycotic Aneurysm Caused by Prevotella intermedia Associated with Chronic Sinusitis in a Korean Adult

et al. 2020

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“…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].…”

Section: Resultsmentioning

confidence: 99%

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

Brito

Silva

Farias

et al. 2017

Proceedings of MOL2NET 2017, International Conference on Multidisciplinary Sciences, 3rd Edition

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Abstract.The antibacterial potential of the most diverse medicinal plants has benefited humanity for centuries, and precisely because of this, the number of studies investigating the antimicrobial activity of essential oils and their components is increasing. However, the hydrophobic character of the essential oils has made the experiments difficult, requiring the use of organic solvents in the tests in order to avoid such complications. Among the most commonly used solvents are dimethylsulfoxide (DMSO/C2H6OS). To date, the literature has not yet determined a standardization of the usual concentration of DMSO suitable for bacterial experiments, so that its use does not check the efficacy of the tested phytoconstituent by interactions between the solvent and the exploited compound. In view of this reality, the present study intends to standardize the DMSO concentrations that do not interfere in the viability of the bacterial strains of Escherichia coli ATCC 25922, Staphylococcus aureus ATCC MOL2NET, 2017, 3, doi:10.3390/mol2net-03-xxxx 2 25923, Pseudomonas aeruginosa ATCC 27853, Proteus mirabilis ATCC 25922 and Enterococcus faecalis ATCC 29212. In order to reach this objective, the disc diffusion method in Müller Hinton Agar of a reagent impregnated on a filter paper disc was used, using different concentrations of DMSO to determine the minimum inhibitory concentration (MIC) of the five microorganisms listed. The experiment was carried out in triplicate in order to safeguard the effectiveness of the method tested. The incubation was done in an oven at 35º C, for a period of 24 hours. For the test method the conclusions of the tests performed were expressed by the arithmetic mean of the diameter of the inhibition halos formed around the disks. The test demonstrates that for the concentrations and microorganisms tested, DMSO provides safety in its use. IntroductionIn the scientific field, extracts and essential oils from plants are used as natural sources of new compounds to combat bacterial infections. However, the estimation of the antibacterial activities of many plant-derived compounds is hampered by the low solubility of these compounds in water. Solubilizers, such as surfactants and solvents, among them dimethylsulfoxide (DMSO), have been used to solve this problem, but it may be difficult to distinguish the contribution in the antimicrobial activity of the solubilizer from the compounds under investigation [1]. DMSO was originally synthesized by Zaytsev in 1866, and has since been extensively investigated for possible industrial and biological utility, and a considerable amount of literature has developed on its properties and uses [2]. It is an organosulfur of formula C2H6OS of molecular weight 78 g/mol, boiling point 189 °C and freezing temperature 18.5 °C; an amphipathic molecule composed of a polar domain characterized by sulfinyl and two non-polar methyl groups, which makes it capable of solubilizing polar and non-polar substances and transposing hydrophobic barriers (Figure 1) [3].

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“…In vivo studies highlight links between the long-term microbiota compositional changes and host dysbiosis, including the development of allergic, metabolic, immunological and inflammatory diseases 5-8,10,11,19-21 . While uncovering the direct effects of different antibiotics on our gut flora is critical to improve general health, technical difficulties hamper routine testing of antibiotic susceptibility in anaerobes 22,23 . Currently available data on bacterial susceptibility to antibiotics is focused on invasive pathogens and offers little to no resolution in the diversity of the human gut microbiota 24 .…”

Section: Main Textmentioning

confidence: 99%

Dissecting the collateral damage of antibiotics on gut microbes

Maier

Goemans

Pruteanu

et al. 2020

Preprint

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24Antibiotics are used for fighting pathogens, but also target our commensal bacteria as a side 25 effect, disturbing the gut microbiota composition and causing dysbiosis and disease 1-3 . 26Despite this well-known collateral damage, the activity spectrum of the different antibiotic 27 classes on gut bacteria remains poorly characterized. Having monitored the activities of 28 >1,000 marketed drugs on 38 representative species of the healthy human gut microbiome 4 , 29 we here characterize further the 144 antibiotics therein, representing all major classes. We 30 determined >800 Minimal Inhibitory Concentrations (MICs) and extended the antibiotic 31 profiling to 10 additional species to validate these results and link to available data on 32 antibiotic breakpoints for gut microbes. Antibiotic classes exhibited distinct inhibition spectra, 33including generation-dependent effects by quinolones and phylogeny-independence by β-34 lactams. Macrolides and tetracyclines, two prototypic classes of bacteriostatic protein 35 synthesis inhibitors, inhibited almost all commensals tested. We established that both kill 36 different subsets of prevalent commensal bacteria, and cause cell lysis in specific cases. 37This species-specific activity challenges the long-standing divide of antibiotics into 38 bactericidal and bacteriostatic, and provides a possible explanation for the strong impact of 39 macrolides on the gut microbiota composition in animals 5-8 and humans 9-11 . To mitigate the 40 collateral damage of macrolides and tetracyclines on gut commensals, we exploited the fact 41 that drug combinations have species-specific outcomes in bacteria 12 and sought marketed 42 drugs, which could antagonize the activity of these antibiotics in abundant gut commensal 43 species. By screening >1,000 drugs, we identified several such antidotes capable of 44 protecting gut species from these antibiotics without compromising their activity against 45 relevant pathogens. Altogether, this study broadens our understanding of antibiotic action on 46 gut commensals, uncovers a previously unappreciated and broad bactericidal effect of 47 prototypical bacteriostatic antibiotics on gut bacteria, and opens avenues for preventing the48 collateral damage caused by antibiotics on human gut commensals.49 3 MAIN TEXT 50 Medication is emerging as major contributor for changes in the composition of the human gut 51 microbiota 4,13-15 . Such severe and long-lasting changes are associated, and in some cases 52 causatively linked, to dysbiosis and a wide range of diseases 16 . Although several non-53 antibiotic drugs may also have a previously unappreciated impact on the gut microbiome 54 composition 4,16,17 , antibiotics, developed to have broad spectra and thereby target very 55 diverse pathogens, are long known to take a heavy toll on our gut flora, causing a variety of 56 gastrointestinal side-effects 18 , including Clostridioides (former Clostridium) difficile infections. 57Recently more attention has been given to this collateral damage of antibiot...

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

Cited by 143 publications

References 188 publications

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

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

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

Dissecting the collateral damage of antibiotics on gut microbes

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