natamycin + ceftazidime + vancomycin

This is a combination of three antimicrobial agents—natamycin, ceftazidime, and vancomycin—used together for the treatment of severe or resistant infections, particularly in ophthalmology (such as infectious endophthalmitis) and in immunocompromised patients. - **Natamycin** is a polyene antifungal that binds to ergosterol in fungal cell membranes, increasing membrane permeability and causing cell death. - **Ceftazidime** is a third-generation cephalosporin antibiotic with broad-spectrum activity against Gram-negative bacteria (notably Pseudomonas aeruginosa) and some Gram-positive organisms; it inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins. - **Vancomycin** is a glycopeptide antibiotic effective against Gram-positive bacteria (including MRSA); it inhibits bacterial cell wall synthesis by binding to D-Ala-D-Ala termini of peptidoglycan precursors. The combination may be used empirically for severe ocular infections or febrile neutropenia when both fungal and broad-spectrum antibacterial coverage are needed. Ceftazidime plus vancomycin is commonly used intravitreally for endophthalmitis; natamycin adds antifungal coverage if fungal infection is suspected or confirmed[3][8]. Care must be taken with administration due to potential incompatibility between vancomycin and ceftazidime when mixed together[3].