Current concepts in laboratory testing to guide antimicrobial therapy.

Area of Science:

• Clinical Microbiology
• Infectious Diseases
• Pharmacology

Background:

• Antimicrobial susceptibility testing (AST) is essential for guiding antimicrobial therapy when pathogen identity doesn't reliably predict susceptibility.
• It's most critical for bacteria exhibiting resistance to common antibiotics.
• Certain pathogens, like Streptococcus pyogenes, have predictable susceptibility, often allowing for empirical therapy without AST.

Purpose of the Study:

• To outline the indications and value of antimicrobial susceptibility testing (AST).
• To discuss various laboratory methods for assessing bacterial susceptibility and resistance.
• To highlight the complementary role of phenotypic and molecular methods alongside AST.

Main Methods:

• Review of indications for AST in clinical practice.
• Description of standard laboratory methods for in vitro susceptibility testing.
• Discussion of phenotypic and molecular methods for detecting antimicrobial resistance mechanisms.

Main Results:

• AST is indicated when reliable prediction of antimicrobial susceptibility is not possible.
• It is valuable for evaluating new antimicrobial compounds and studying antimicrobial resistance epidemiology.
• Phenotypic and molecular methods complement AST by providing rapid detection of resistance mechanisms and carriage states.

Conclusions:

• AST is a critical tool for optimizing antimicrobial therapy and managing infectious diseases.
• The judicious use of AST, alongside emerging phenotypic and molecular techniques, is vital for combating antimicrobial resistance.
• Understanding the limitations and appropriate application of AST is crucial for accurate clinical decision-making.