In microbiology, a strain refers to a genetically distinct variant of a microorganism, such as bacteria, viruses, or fungi. Strains can emerge due to mutations or adaptations to environmental conditions, leading to variations in characteristics such as virulence, antibiotic resistance, or nutrient utilization. Classifying microorganisms into strains is essential for understanding their behavior, epidemiology, and potential impacts on health and ecosystems. This differentiation aids researchers and healthcare professionals in developing targeted treatments and interventions.