Direct susceptibility testing by disk diffusion on clinical samples: a rapid and accurate tool for antibiotic stewardship

Coorevits, Liselotte; Boelens, Jerina; Claeys, Geert

doi:10.1007/s10096-015-2349-2

Cited by 43 publications

(44 citation statements)

References 23 publications

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“…A significant correlation has been reported previously for disk diffusion and BMD assays for many species/drug combinations (e.g. Berghaus et al, 2014;Coorevits et al, 2015;Matar et al, 2003).…”

Section: Correlation Between Disk Diffusion and Broth Microdilution Asupporting

confidence: 68%

diskImageR: quantification of resistance and tolerance to antimicrobial drugs using disk diffusion assays

et al. 2016

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Microbial pathogens represent an increasing threat to human health. Although many infections can be successfully treated and cleared, drug resistance is a widespread problem. The existence of subpopulations of 'tolerant' cells (where a fraction of the population is able to grow above the population resistance level) may increase the rate of treatment failure; yet, existing methods to measure subpopulation effects are cumbersome. Here we describe diskImageR, a computational pipeline that analyses photographs of disk diffusion assays to determine the degree of drug susceptibility [the radius of inhibition, (RAD)], and two aspects of subpopulation growth [the fraction of growth (FoG) within the zone of inhibition, (ZOI), and the rate of change in growth from no drug to inhibitory drug concentrations, (SLOPE)]. diskImageR was used to examine the response of the human fungal pathogen Candida albicans to the antifungal drug fluconazole across different strain backgrounds and growth conditions. Disk diffusion assays performed under Clinical and Laboratory Standards Institute (CLSI) conditions led to more susceptibility and less tolerance than assays performed using rich medium conditions. We also used diskImageR to quantify the effects of three drugs in combination with fluconazole, finding that all three combinations affected tolerance, with the effect of one drug (doxycycline) being very strain dependent. The three drugs had different effects on susceptibility, with doxycycline generally having no effect, chloroquine generally increasing susceptibility and pyrvinium pamoate generally reducing susceptibility. The ability to simultaneously quantitate different aspects of microbial drug responses will facilitate the study of mechanisms of subpopulation responses in the presence of antimicrobial drugs.

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Section: Correlation Between Disk Diffusion and Broth Microdilution Asupporting

confidence: 68%

diskImageR: quantification of resistance and tolerance to antimicrobial drugs using disk diffusion assays

et al. 2016

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“…The main criticism of such direct susceptibility test (DST) is the non-standardized sample and mixed cultures, which may lead to inaccurate results 22 , 23 . Nevertheless, numerous studies conducted over the past two decades indicate the applicability of DST in the diagnosis of infections 24 – 27 .…”

Section: Resultsmentioning

confidence: 99%

Culture-free bacterial detection and identification from blood with rapid, phenotypic, antibiotic susceptibility testing

Shi

Kadiyala

Yau

2018

Sci Rep

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The current culture-based approach for the diagnosis of bloodstreams infection is incommensurate with timely treatment and curbing the prevalence of multi-drug resistant organisms (MDROs) due to its long time-to-result. Bloodstream infections typically involve extremely low (e.g., <10 colony-forming unit (CFU)/mL) bacterial concentrations that require a labor-intensive process and as much as 72 hours to yield a diagnosis. Here, we demonstrate a culture-free approach to achieve rapid diagnosis of bloodstream infections. An immuno-detection platform with intrinsic signal current amplification was developed for the ultrasensitive, rapid detection, identification (ID) and antibiotic susceptibility testing (AST) of infections. With its capability of monitoring short-term (1–2 hours) bacterial growth in blood, the platform is able to provide 84-minute simultaneous detection and ID in blood samples below the 10 CFU/mL level and 204-minute AST. The susceptible-intermediate-resistant AST capacity was demonstrated.

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“…A recent study by Rosa et al concluded that Sysmex UF-5000 showed high diagnostic accuracy in UTI screening with a low rate of false negatives, and that the instrument can predict Gram negative bacteria with a high sensitivity and in high agreement with culture [8]. Direct AST on urine has been evaluated in previous studies [20][21][22][23][24] with promising results. Recently, Wei et al recently suggested the combination of flow cytometry (UF 1000), MALDI-TOF, MS, and VITEK 2 provided a direct, rapid, and reliable identification and AST method for assessing urine samples, especially for Gram negative bacterial infections [25].…”

Section: Direct Antibiotic Susceptibility Testingmentioning

confidence: 99%

Rapid diagnosis and reduced workload for urinary tract infection using flowcytometry combined with direct antibiotic susceptibility testing

Gilboe¹,

Reiakvam²,

Aasen³

et al. 2021

PLoS ONE

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Background We evaluated if flowcytometry, using Sysmex UF-5000, could improve diagnosis of urinary tract infections by rapid identification of culture negative and contaminated samples prior to culture plating, thus reducing culture plating workload and response time. We also evaluated if it is possible to reduce the response time for antibiotic susceptibility profiles using the bacteria information flag on Sysmex UF-5000 to differentiate between Gram positive and negative bacteria, followed by direct Antibiotic Susceptibility Testing (dAST) on the positive urine samples. Methods One thousand urine samples were analyzed for bacteria, white blood cells and squamous cells by flowcytometry before culture plating. Results from flowcytometric analysis at different cut-off values were compared to results of culture plating. We evaluated dAST on 100 urine samples that were analyzed as positive by flowcytometry, containing either Gram positive or Gram negative bacteria. Results Using a cut-off value with bacterial count ≥100.000/mL and WBCs ≥10/μL, flowcytometry predicted 42,1% of samples with non-significant growth. We found that most contaminated samples contain few squamous cells. For 52/56 positive samples containing Gram negative bacteria dAST was identical to routine testing. Overall, there was concordance in 555/560 tested antibiotic combinations. Conclusion Flowcytometry offers advantages for diagnosis of urinary tract infections. Screening for negative urine samples on the day of arrival reduces culture plating and workload, and results in shorter response time for the negative samples. The bacteria information flag predicts positive samples containing Gram negative bacteria for dAST with high accuracy, thus Antibiotic Susceptibility Profile can be reported the day after arrival. For the positive samples containing Gram negative bacteria the concordance was very good between dAST and Antibiotic Susceptibility Testing in routine. For positive samples containing Gram positive bacteria the results were not convincing. We did not find any correlation between epithelial cells and contamination.

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Direct susceptibility testing by disk diffusion on clinical samples: a rapid and accurate tool for antibiotic stewardship

Cited by 43 publications

References 23 publications

diskImageR: quantification of resistance and tolerance to antimicrobial drugs using disk diffusion assays

diskImageR: quantification of resistance and tolerance to antimicrobial drugs using disk diffusion assays

Culture-free bacterial detection and identification from blood with rapid, phenotypic, antibiotic susceptibility testing

Rapid diagnosis and reduced workload for urinary tract infection using flowcytometry combined with direct antibiotic susceptibility testing

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