Bacterial adhesion and biofilm formation are critical for bacterial survival and pathogenesis. Biofilms are structured communities of bacterial cells enclosed in a self-produced polymeric matrix, adherent to surfaces, and composed of microbes, glycocalyx, and surface. Biofilms are universal, found on various surfaces, including biomedical implants, and are essential for bacterial survival in diverse environments. The glycocalyx, a complex of exopolysaccharides and trapped substances, protects bacteria from environmental threats and enhances resistance to antimicrobial agents. Biofilm formation involves primary adhesion (docking) and secondary adhesion (locking), with surface conditioning playing a key role in the initial interaction between bacteria and surfaces. Biofilm maturation is influenced by environmental factors, nutrient availability, and microbial interactions, leading to increased resistance to antimicrobial agents. Biofilms can also act as molecular filters, altering the effectiveness of antimicrobial treatments. The architecture of biofilms is complex, with varying thickness and cellular composition, and is influenced by factors such as nutrient availability and microbial interactions. Biofilm resistance is multifactorial, involving physical barriers, altered growth rates, and microenvironmental conditions. Understanding biofilm formation and resistance is crucial for developing effective antimicrobial strategies, particularly in the context of biomedical implants and infections. The study of biofilms has led to the development of new methods for testing antimicrobial susceptibility, emphasizing the importance of considering biofilm conditions in clinical microbiology.Bacterial adhesion and biofilm formation are critical for bacterial survival and pathogenesis. Biofilms are structured communities of bacterial cells enclosed in a self-produced polymeric matrix, adherent to surfaces, and composed of microbes, glycocalyx, and surface. Biofilms are universal, found on various surfaces, including biomedical implants, and are essential for bacterial survival in diverse environments. The glycocalyx, a complex of exopolysaccharides and trapped substances, protects bacteria from environmental threats and enhances resistance to antimicrobial agents. Biofilm formation involves primary adhesion (docking) and secondary adhesion (locking), with surface conditioning playing a key role in the initial interaction between bacteria and surfaces. Biofilm maturation is influenced by environmental factors, nutrient availability, and microbial interactions, leading to increased resistance to antimicrobial agents. Biofilms can also act as molecular filters, altering the effectiveness of antimicrobial treatments. The architecture of biofilms is complex, with varying thickness and cellular composition, and is influenced by factors such as nutrient availability and microbial interactions. Biofilm resistance is multifactorial, involving physical barriers, altered growth rates, and microenvironmental conditions. Understanding biofilm formation and resistance is crucial for developing effective antimicrobial strategies, particularly in the context of biomedical implants and infections. The study of biofilms has led to the development of new methods for testing antimicrobial susceptibility, emphasizing the importance of considering biofilm conditions in clinical microbiology.