Dataset Information

TDtest: easy detection of bacterial tolerance and persistence in clinical isolates by a modified disk-diffusion assay.

ABSTRACT: Antibiotic tolerance - the ability for prolonged survival under bactericidal treatments - is a potentially clinically significant phenomenon that is commonly overlooked in the clinical microbiology laboratory. Recent in vitro experiments show that high tolerance can evolve under intermittent antibiotic treatments in as little as eight exposures to high doses of antibiotics, suggesting that tolerance may evolve also in patients. However, tests for antibiotic susceptibilities, such as the disk-diffusion assay, evaluate only the concentration at which a bacterial strain stops growing, namely resistance level. High tolerance strains will not be detected using these tests. We present a simple modification of the standard disk-diffusion assay that allows the semi-quantitative evaluation of tolerance levels. This novel method, the "TDtest", enabled the detection of tolerant and persistent bacteria by promoting the growth of the surviving bacteria in the inhibition zone, once the antibiotic has diffused away. Using the TDtest, we were able to detect different levels of antibiotic tolerance in clinical isolates of E. coli. The TDtest also identified antibiotics that effectively eliminate tolerant bacteria. The additional information on drug susceptibility provided by the TDtest should enable tailoring better treatment regimens for pathogenic bacteria.

SUBMITTER: Gefen O

PROVIDER: S-EPMC5286521 | biostudies-literature | 2017 Feb

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

TDtest: easy detection of bacterial tolerance and persistence in clinical isolates by a modified disk-diffusion assay.

Gefen Orit O Chekol Betty B Strahilevitz Jacob J Balaban Nathalie Q NQ

Scientific reports 20170201

Antibiotic tolerance - the ability for prolonged survival under bactericidal treatments - is a potentially clinically significant phenomenon that is commonly overlooked in the clinical microbiology laboratory. Recent in vitro experiments show that high tolerance can evolve under intermittent antibiotic treatments in as little as eight exposures to high doses of antibiotics, suggesting that tolerance may evolve also in patients. However, tests for antibiotic susceptibilities, such as the disk-dif ...[more]

PMID: 28145464

Similar Datasets

Project description:PurposeTo determine the presence of 4 clinically relevant bacterial endosymbionts in Acanthamoeba isolates obtained from patients with Acanthamoeba keratitis (AK) and the possible contribution of endosymbionts to the pathogenesis of AK.DesignExperimental study.ParticipantsAcanthamoeba isolates (N = 37) recovered from the cornea and contact lens paraphernalia of 23 patients with culture-proven AK and 1 environmental isolate.MethodsAcanthamoeba isolates were evaluated for the presence of microbial endosymbionts belonging to the bacterial genera Legionella, Pseudomonas, Mycobacterium, and Chlamydia using molecular techniques (polymerase chain reaction and sequence analysis, fluorescence in situ hybridization) and transmission electron microscopy. Corneal toxicity and virulence of Acanthamoeba isolates with and without endosymbionts were compared using a cytopathic effect (CPE) assay on human corneal epithelial cells in vitro. Initial visual acuity, location and characteristics of the infiltrate, time to detection of the infection, and symptom duration at presentation were evaluated in all patients.Main outcome measuresPrevalence and potential pathobiology of bacterial endosymbionts detected in Acanthamoeba isolates recovered from AK.ResultsTwenty-two (59.4%) of the 38 cultures examined contained at least 1 bacterial endosymbiont. One isolate contained 2 endosymbionts, Legionella and Chlamydia, confirmed by fluorescence in situ hybridization. Corneal toxicity (CPE) was significantly higher for Acanthamoeba-hosting endosymbionts compared with isolates without endosymbionts (P<0.05). Corneal pathogenic endosymbionts such as Pseudomonas and Mycobacterium enhanced Acanthamoeba CPE significantly more than Legionella (P<0.05). In the presence of bacterial endosymbionts, there was a trend toward worse initial visual acuity (P>0.05), central location (P<0.05), absence of radial perineuritis (P<0.05), delayed time to detection (P>0.05), and longer symptom duration at presentation (P>0.05).ConclusionsMost Acanthamoeba isolates responsible for AK harbor 1 or more bacterial endosymbionts. The presence of endosymbionts enhances the corneal pathogenicity of Acanthamoeba isolates and may impact detection time and clinical features of AK.

Dataset Information

TDtest: easy detection of bacterial tolerance and persistence in clinical isolates by a modified disk-diffusion assay.

Publications

TDtest: easy detection of bacterial tolerance and persistence in clinical isolates by a modified disk-diffusion assay.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets