Table 2.
Alternative intravitreal antimicrobial agents for potential use in management of endophthalmitis caused by organisms resistant to standard antimicrobials.
| Organisms | Name of drugs | Class of drugs | Mechanism of Action | Intravitreal dose |
|---|---|---|---|---|
| GPO | Linezolid (Zyvox®) |
Oxazolindinone (fermentation byproduct of Streptomyces roseosporus) |
Inhibits initiation of protein synthesis by binding 23S rRNA of the 50S subunit of bacterial ribosome. |
300 micrograms/0.1ml53 (rabbits) |
| Quinupristin/dalfopristin (Synercid®) |
Streptogramin (isolated from Streptomyces pristinapsiralis) |
Inhibits bacterial protein synthesis by interfering with function of 23S RNA (quinupristin:dalfopristin=3:7) |
0.4 milligram/0.1ml47-49 (rabbits and case reports in humans) |
|
| Daptomycin (Cubicin®) |
Cyclic lipoglycopeptide | Terminates bacterial DNA, RNA and protein synthesis and cell death by forming transmembrane channels in cell membrane and depolarization of membrane potential. |
200 micrograms/0.1ml50-52 (case report in humans) |
|
| Tigecycline (Tygacil®) |
Glycylcycline (a derivative of minocycline) |
Inhibits bacterial protein synthesis by irreversibly binding to 30 S ribosomal unit |
0.5-1 milligrams/0.1ml54 (rabbits) |
|
| GNO | Imipenem (Primaxin®) |
Carbapenem | Interrupts cell wall synthesis of various GPO & GNO and is a strong inhibitor of β-lactamases from some GNO that are resistant to most β-lactam antibiotics. |
50 micrograms/0.1 mL11,55 (case series in humans) |
| Ciprofloxacin (Cipro®) |
Fluoroquinolones | Inhibition of the enzymes topoisomerase II (DNA gyrase) and topoisomerase IV, which are required for bacterial DNA replication, transcription, repair, and recombination. |
0.1 milligrams/0.1ml | |
| Levofloxacin (Levaquin®) |
Fluoroquinolones | Same as above | 0.1ml of 0.5% ophthalmic solution57 (rabbits) |
|
| Moxifloxacin (Avelox®) |
Fluoroquinolones | Same as above | 0.2 milligrams/0.1ml58 (case report in humans) |
|
| Fungi | Miconazole | Azole | Effects on respiration and cell permeability. It inhibits the growth of several species of Candida. |
25 micrograms/0.1ml60 (case series in humans) |
| Caspofungin (Cancidas®) |
Echinocandin | Blocks the synthesis of β(1,3)-d-glucan of the fungal cell wall, by non-competitive inhibition of the enzyme β(1,3)-d-glucan synthase. β(1,3)-d-Glucan is an essential component of the cell wall of numerous fungal species. |
50 micrograms/0.1 ml59,61 (rabbits and mice) |
|
| Micafungin (Mycamine®) |
Echinocandin | It inhibits an enzyme essential for fungal cell-wall synthesis. |
0.025 milligrams/0.1 ml (rabbits)* |
GPO-gram-positive organisms, GNO-gram-negative organisms
*
ARVO Annual Meeting Abstract, April 2010 - Kapur R; Kim B; Tu EY; Birnbaum A; Fiscella R; Navare S; Blair MP; Edward DP; Carroll J; Lim JI. The Safe and Non-Toxic Dose of Intravitreal Micafungin and Caspofungin in a Rabbit Model.