Automated Identification and Antimicrobial Susceptibility Testing
How automated systems identify bacteria and generate MICs, how they differ from manual methods, and when an automated result should be confirmed before it is reported.
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Antimicrobial Susceptibility Testing
Methods for testing antibiotic susceptibility in clinical microbiology
Antimicrobial Stewardship and the Microbiology Laboratory: How Bench Decisions Shape Prescribing
Antimicrobial stewardship is usually taught as a hospital program. This article teaches the part students actually need: how the microbiology laboratory drives stewardship through...
AmpC Beta-Lactamase Detection: Cefoxitin Screen, Inhibitor Confirmation, and Telling It Apart from an ESBL
How the lab detects an AmpC beta-lactamase: the cefoxitin screen, the cloxacillin and boronic acid confirmatory tests, chromosomal versus plasmid-mediated AmpC, and the inhibitor l...
Antimicrobial Susceptibility Testing (AST): Methods, Interpretation, and How to Choose
How antimicrobial susceptibility testing works, when to use disk diffusion vs. dilution vs. gradient vs. automated methods, how CLSI and EUCAST breakpoints turn a measurement into...
ESBL Detection: Screening, the Combined-Disk Confirmatory Test, and the AmpC Trap
How the lab detects an extended-spectrum beta-lactamase: the screening cutoffs, the CLSI combined-disk confirmatory test and its ≥5 mm rule, the control strains, and why a co-produ...
McFarland Densitometer: Parts, Principle, and Operation
How a McFarland densitometer works: its parts, photometric principle, operation, and calibration. It reads bacterial suspension turbidity directly in McFarland units for susceptibi...
Beta-Lactamase Classification: Ambler vs. Bush-Jacoby, and Why an Enzyme Has Both
How the Ambler molecular classes (A through D) and Bush-Jacoby functional groups describe the same enzymes from two different angles, with the mapping most articles skip.
Phenotypic Methods for the Detection of Carbapenemases
Phenotypic Methods for the Detection of Carbapenemases
Carba NP Test (CNPt): Principle, Procedure, Results
Carba NP Test (CNPt): Principle, Procedure, Results
MIC vs MBC: What Each Measures and When the Difference Actually Matters
MIC stops bacterial growth; MBC kills it. Learn how MBC is determined from MIC tubes, the MBC/MIC ratio, and the specific clinical scenarios (endocarditis, osteomyelitis, neutropen...
McFarland Turbidity Standards: Preparation and Use in Susceptibility Testing
How McFarland turbidity standards are prepared, why the 0.5 standard (1.5 x 10^8 CFU/mL) is the target for antimicrobial susceptibility testing, and how a wrong inoculum density gi...
E-Test (Epsilometer): Why It Beats a Plain Disc Test, Procedure & Reading Rules
E-test gives an exact MIC value, not just a Susceptible/Resistant call. Full procedure, strip placement, and the reading rules that trip up most students plus how E-test strips are...
Modified Hodge Test (MHT): Procedure, and Why CLSI No Longer Recommends It
MHT detects carbapenemase via a clover-leaf growth pattern, and CLSI dropped it from its guidelines in 2018 in favor of mCIM and Carba NP. The procedure, the limitations that led t...
Stokes Disc Diffusion Method: Why the Control Shares the Plate
Stokes disc diffusion runs a susceptible control strain on the same plate as the test isolate, so weak discs or off media distort both zones equally and the comparison still holds.
Broth Dilution Method for MIC: Macrodilution vs Microdilution, Procedure & Troubleshooting
Step-by-step broth macrodilution and microdilution procedure for MIC determination: antibiotic stock prep, 0.5 McFarland standardization, reading results, and a troubleshooting gui...
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