Antimicrobial susceptibility testing

ESKAPE Pathogens

ESKAPE Pathogens

ESKAPE is the acronym for six nosocomial pathogens that can ‘escape’ commonly used antibiotics and can develop into MDR.

Quality Control Strains (standard strains) and their Uses

Quality Control Strains (standard strains) and their Uses

QC strains are also used to monitor the test procedure and quality control of culture media & reagents.

Phenotypic Methods for the Detection of Carbapenemases

Phenotypic Methods for the Detection of Carbapenemases

Phenotypic assays to detect carbapenemase-producing organisms are either growth-based assays (MHT or CIM) or hydrolysis methods.

Minimum Inhibitory Concentration (MIC)  and  Minimum Bactericidal Concentration (MBC)

Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC)

MIC test determines the antimicrobial activity of a test agent against a specific bacteria. It is done via E-test, tube/agar dilution method.

Preparation of McFarland Turbidity Standards

Preparation of McFarland Turbidity Standards

For performing AST using Kirby Bauer disc diffusion method, a cell suspension of organisms equivalent to a 0.5 McFarland standard is used.

Nitrocefin test: Principle, Procedure, Uses

Nitrocefin test: Principle, Procedure, Uses

The nitrocefin test is a sensitive technique for detecting beta-lactamase-producing strains of N. gonorrhoeae, H. influenzae, Enterococcus spp.

E-TEST (Epsilometer): Principle, Procedure, Results

E-TEST (Epsilometer): Principle, Procedure, Results

Quantative method for detecting MIC by using the principles of both dilution and diffusion of antibiotics into the medium.

Modified Hodge Test (MHT) for Carbapenemase Detection

Modified Hodge Test (MHT) for Carbapenemase Detection

Modified Hodge test (MHT) is a simple phenotypic test for the detection of the presence of carbapenemase enzyme in bacteria.

Stokes Disc Diffusion Method: Principle, Procedure, Results

Stokes Disc Diffusion Method: Principle, Procedure, Results

Stokes’ disc diffusion method allows each individual isolate to be compared with a sensitive control of the same or similar species.

Modified Kirby-Bauer Disc Diffusion Method

Modified Kirby-Bauer Disc Diffusion Method

Modified Kirby-Bauer disc diffusion test method is a reference method to test the susceptibility of a bacterial isolate in a clinical laboratory.

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Antibiotics used in routine Antimicrobial susceptibility testing (AST)

What does Susceptible, Intermediate, and Resistant Mean?

What does Susceptible, Intermediate, and Resistant Mean?

Susceptible organism is likely to respond to treatment with this drug, at the recommended dosage but resistant wont respond.

Selection of Antimicrobials for Antimicrobial Testing

Selection of Antimicrobials for Antimicrobial Testing

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Preparation of Antibiotic Stock Solutions and Discs

Inducible Clindamycin Resistance (D Test)

Inducible Clindamycin Resistance (D Test)

Inducible clindamycin resistance should be checked in all staphylococci that are erythromycin-resistant and clindamycin susceptible or intermediate.

Mueller Hinton Agar (MHA): Composition, Preparation, Uses

Mueller Hinton Agar (MHA): Composition, Preparation, Uses

Best medium to use for routine susceptibility testing for non-fastidious bacteria.

Guidelines for Routine Antibiotic Susceptibility Testing (AST)

Guidelines for Routine Antibiotic Susceptibility Testing (AST)