Antimicrobial Resistance

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.

ESBL and Classification of β-lactamases

ESBL and Classification of β-lactamases

ESBL are a group of enzymes produced by both Gram-negative and Gram-positive bacteria which can hydrolyze all β- lactam agents except

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.

WHO AWaRe Classification of Antibiotics

WHO AWaRe Classification of Antibiotics

AWaRe classifies antibiotics into three stewardship groups: Access, Watch and Reserve to emphasize their optimal use.

Carba NP Test (CNPt): Principle, Procedure, Results

Carba NP Test (CNPt): Principle, Procedure, Results

Carba NP test (CNPt) is a biochemical test for rapid detection of carbapenemase production on Gram-negative bacilli.

Macrolides: Mode of Action, Mechanism of Resistance

Macrolides: Mode of Action, Mechanism of Resistance

Macrolides (erythromycin, azithromycin, clarithromycin) inhibit bacterial protein synthesis by binding with the 50S subunit of the ribosome.

Tetracyclines: Mode of Action and Mechanism of Resistance

Tetracyclines: Mode of Action and Mechanism of Resistance

Tetracyclines are broad-spectrum, bacteriostatic antibiotics for Gram-positive, Gram-negative bacteria, and intracellular bacteria.

Beta-Lactam Antibiotics: Mechanism of Action, Resistance

Beta-Lactam Antibiotics: Mechanism of Action, Resistance

Penicillins, cephalosporins, monobactams, and carbapenems are major beta-lactam antibiotics; active against both gram-positive and negative bacteria.

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.

Glycopeptides (Vancomycin, Teicoplanin)

Glycopeptides (Vancomycin, Teicoplanin)

Glycopeptide antibiotics act by inhibiting cell wall synthesis of bacteria. Vancomycin, a glycopeptide drug is used to treat MRSA infections.

MRSA: Emergence, Types, Detection Methods

MRSA: Emergence, Types, Detection Methods

MRSA (methicillin-resistant Staphylococcus aureus) is resistant to all ß-lactam agents, including cephalosporins and carbapenems.

Antibiotic Resistance: Origin, Causes, Mechanism

Antibiotic Resistance: Origin, Causes, Mechanism

Decreased permeability, efflux pump, altered target, and inactivation of antibiotics are major mechanisms of drug resistance.

Bacteria Associated with Intrinsic Antibiotic Resistance

Bacteria Associated with Intrinsic Antibiotic Resistance

There are innumerable species of bacteria which are innately resistant to particular drugs. For example, penicillin resistance of Mycoplasma.

World Antibiotic Awareness Week Celebration

World Antibiotic Awareness Week Celebration

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.

Teixobactin: Introduction, Mechanism of Action, Uses

Teixobactin: Introduction, Mechanism of Action, Uses

Teixobactin is an extract of β-proteobacteria named Eleftheria terrae. It has shown excellent activity against Gram-positive bacteria.

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.

Broth Dilution Method for MIC Determination

Broth Dilution Method for MIC Determination

MIC can be determined by broth dilution or agar dilution methods. Broth dilution testing allows the option of providing both quantitative MIC and qualitative results.

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Preparation of Antibiotic Stock Solutions and Discs

Guidelines for Routine Antibiotic Susceptibility Testing (AST)

Guidelines for Routine Antibiotic Susceptibility Testing (AST)