The present disclosure provides antimicrobial coating compositions that are used to form residual antimicrobial coatings on medical implements and medical devices including the components of medical equipment such as CPAP/BiPAP machines. Antimicrobial coating compositions comprise at least one of an organosilane (R1O)3Si—R2—Z, an organic amine R9R10R11N, a titanium (IV) species, a 1,2-diol, an α-hydroxy acid, β-hydroxy acid, and an organosilane grafted parylene polymer, wherein R1 is H, alkyl, substituted alkyl, aryl or substituted aryl, R2 is a bivalent linker, Z is a nucleophile, leaving group, or quaternary nitrogen substituent, and R9, R10, and R11 are independently H, alkyl, substituted alkyl, aryl, substituted aryl or cyclic.