Final answer:
Antibiotic resistance genes are commonly located on plasmids or transposons and can be spread through horizontal gene transfer or passed down to subsequent microbial generations.
Step-by-step explanation:
Genes responsible for antibiotic resistance are usually located on mobile genetic elements within bacteria, such as plasmids or transposons. These elements facilitate the easy transfer of resistance genes between different bacteria through mechanisms like horizontal gene transfer, which includes processes such as transformation, conjugation, and transduction. Additionally, resistance genes can also be transferred vertically to subsequent generations of microbes, potentially becoming predominant within populations exposed repeatedly to antibiotics. Problematic, antibiotic-resistant microbial strains are often transmitted in clinical settings, though community-acquired instances are also of concern.