Antibiotic Discs
Antibiotic Discs - Related Videos
13:39
Antibiotic Susceptibility Testing: Epsilometer Tests to Determine MIC Values of Two Antibiotics and Evaluate Antibiotic Synergy
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2023
Source: Anna Bläckberg1, Rolf Lood1 1 Department of Clinical Sciences Lund, Division of Infection Medicine, Biomedical Center, Lund University, 221 00 Lund Sweden Knowledge of the interactions between antibiotics and bacteria is important in understanding how microbes evolve antibiotic resistance. In 1928, Alexander Fleming discovered penicillin, an antibiotic that exerts its antibacterial function by interfering with cell wall regeneration (1). Other antibiotics with diverse mechanisms of...
08:03
An In Vitro Organ Culture Model of the Murine Intervertebral Disc
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Cited by 22 •
2017
Whole organ culture of the intervertebral disc (IVD) preserves the native extracellular matrix, cell phenotypes, and cellular-matrix interactions. Here we describe an IVD culture system using mouse lumbar and caudal IVDs in their functional spinal units and several applications utilizing this system.
07:48
Dissection and Mounting of Drosophila Pupal Eye Discs
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Cited by 7 •
2014
The goal of this technique is to enable researchers to perform dissection, immunostaining and mounting of pupal eye discs from Drosophila melanogaster of any age.
10:49
Antibiotic Dereplication Using the Antibiotic Resistance Platform
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Cited by 2 •
2019
We describe a platform that utilizes a library of isogenic antibiotic resistant Escherichia coli for the dereplication of antibiotics. The identity of an antibiotic produced by bacteria or fungi can be deduced by the growth of E. coli expressing its respective resistance gene. This platform is economically effective and time-efficient.
04:27
Generating a Pro-Inflammatory Organ Culture Model to Simulate an Early Intervertebral Disc Disease
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2025
This video demonstrates a technique for culturing bovine intervertebral discs in bioreactors to develop a three-dimensional organ culture model. Specific nutrient-deprived media and degenerative pressure conditions are applied to the discs, mimicking the pro-inflammatory and degenerative microenvironment observed during early-stage intervertebral disc disease. The disc heights are measured post-treatment to analyze the effects of nutrient deprivation and degenerative loading.
FAQs
After placement on agar, the antimicrobial agent moves outward from each disc and forms a concentration gradient. Bacterial growth is inhibited where the local drug concentration is effective, producing a clear zone around the disc. The zone therefore reflects the interaction between the tested bacterium and that particular antimicrobial agent, rather than simply the disc’s physical size.
A clear zone does not have a universal meaning without an interpretive standard. Laboratories measure the zone and compare its size with standardized criteria to classify the bacterium’s response to the tested drug. This approach makes results more consistent and supports clinically meaningful comparisons when selecting among antimicrobial agents for bacterial infections.
Different discs expose the same bacterial isolate to different antimicrobial agents, allowing their activities to be compared under the test conditions. A larger or smaller inhibition zone can indicate that the isolate responds differently to those drugs when interpreted using the relevant standards. This comparison helps identify which tested agents may be more appropriate for further clinical consideration.
Repeated susceptibility testing can reveal changes in how bacterial isolates respond to antimicrobial agents. When interpreted consistently, disc diffusion results help laboratories recognize reduced susceptibility and track emerging resistance patterns. This surveillance role extends beyond an individual patient because aggregated findings can inform awareness of resistance trends and support more informed antimicrobial selection.
The workflow begins with bacterial growth on an agar surface, followed by placement of selected discs containing known antimicrobial concentrations. As the agents diffuse, areas of inhibited growth develop around the discs. Laboratory personnel then measure those zones and interpret the measurements with standardized criteria, producing susceptibility information that can support clinical decisions.
The measured inhibition zone provides evidence about whether the tested bacterium is susceptible to a particular antimicrobial agent according to standardized interpretive criteria. It does not serve as an isolated treatment decision; rather, it supplies laboratory evidence that clinicians can use alongside the identification of a bacterial infection when considering antibiotic selection.
They are useful when a laboratory needs to examine how one bacterial isolate responds to several antimicrobial compounds under the same testing approach. Placing different discs on the agar allows the resulting inhibition zones to be compared after measurement and interpretation. This makes the method suitable for routine susceptibility assessment as well as educational demonstrations of antimicrobial activity.
Their accessible format makes the relationship between antimicrobial exposure and bacterial growth inhibition visible on an agar surface. Students can observe distinct clear zones, measure them, and connect those measurements with standardized interpretation. The exercise reinforces core laboratory ideas, including controlled comparison of antimicrobial compounds, quantitative observation, and the clinical relevance of susceptibility testing.