QC strains are also used to monitor the test procedure and quality control of culture media & reagents.
ESBL are a group of enzymes produced by both Gram-negative and Gram-positive bacteria which can hydrolyze all β- lactam agents except
Phenotypic assays to detect carbapenemase-producing organisms are either growth-based assays (MHT or CIM) or hydrolysis methods.
AWaRe classifies antibiotics into three stewardship groups: Access, Watch and Reserve to emphasize their optimal use.
Carba NP test (CNPt) is a biochemical test for rapid detection of carbapenemase production on Gram-negative bacilli.
Macrolides (erythromycin, azithromycin, clarithromycin) inhibit bacterial protein synthesis by binding with the 50S subunit of the ribosome.
Tetracyclines are broad-spectrum, bacteriostatic antibiotics for Gram-positive, Gram-negative bacteria, and intracellular bacteria.
Penicillins, cephalosporins, monobactams, and carbapenems are major beta-lactam antibiotics; active against both gram-positive and negative bacteria.
MIC test determines the antimicrobial activity of a test agent against a specific bacteria. It is done via E-test, tube/agar dilution method.
Glycopeptide antibiotics act by inhibiting cell wall synthesis of bacteria. Vancomycin, a glycopeptide drug is used to treat MRSA infections.
MRSA (methicillin-resistant Staphylococcus aureus) is resistant to all ß-lactam agents, including cephalosporins and carbapenems.
Decreased permeability, efflux pump, altered target, and inactivation of antibiotics are major mechanisms of drug resistance.
There are innumerable species of bacteria which are innately resistant to particular drugs. For example, penicillin resistance of Mycoplasma.
For performing AST using Kirby Bauer disc diffusion method, a cell suspension of organisms equivalent to a 0.5 McFarland standard is used.
Teixobactin is an extract of β-proteobacteria named Eleftheria terrae. It has shown excellent activity against Gram-positive bacteria.
Quantative method for detecting MIC by using the principles of both dilution and diffusion of antibiotics into the medium.
Modified Hodge test (MHT) is a simple phenotypic test for the detection of the presence of carbapenemase enzyme in bacteria.
Stokes’ disc diffusion method allows each individual isolate to be compared with a sensitive control of the same or similar species.
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.
