Intracameral antibiotic agents for endophthalmitis prophylaxis: a pharmacokinetic model.
OBJECTIVE
To assess in vitro whether intracameral antibiotic agents are plausibly effective prophylaxis against Staphylococcus aureus endophthalmitis.


METHODS
University research laboratory.Staphylococcus aureus was cultured for 8 hours with vancomycin (50 microg/mL) or piperacillin/tazobactam (512/64 microg/mL). Without reducing the bacterial counts, the antibiotic concentration was halved every 2 hours to simulate the half-life of antibiotic agents in the anterior chamber. The number of colony forming units (CFU)/mL was measured at 0, 2, 4, 6, and 8 hours.


RESULTS
Vancomycin inhibited the growth of methicillin-resistant S aureus such that the CFU/mL was 1000 times higher in the control group after 8 hours. Piperacillin/tazobactam nearly eliminated 1 oxacillin-susceptible strain and reduced the CFU/mL of another strain 1000-fold.


CONCLUSIONS
Intracameral vancomycin may inhibit the growth of S aureus in the anterior chamber after surgery. Inhibiting the growth could increase the chances that the eye's innate defenses would eliminate the bacterial contamination that could cause endophthalmitis.
Libre
Peter E
PE
Columbia University, New York, New York, USA. plibre@optonline.net
Della-Latta
Phyllis
P
Chin
Nai Xun
NX
D000900:Anti-Bacterial Agents / Q000008:administration & dosage* / Q000493:pharmacokinetics / Q000494:pharmacology; D009877:Endophthalmitis / Q000382:microbiology* / Q000517:prevention & control*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005123:Eye; D006207:Half-Life; D006801:Humans; D016106:Methicillin Resistance; D010397:Penicillanic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology; D010878:Piperacillin / Q000494:pharmacology; D013203:Staphylococcal Infections / Q000188:drug therapy*; D013211:Staphylococcus aureus / Q000187:drug effects / Q000254:growth & development / Q000502:physiology; D000078142:Tazobactam; D014640:Vancomycin / Q000008:administration & dosage* / Q000493:pharmacokinetics / Q000494:pharmacology
D000900:Anti-Bacterial Agents; D004791:Enzyme Inhibitors; D014640:Vancomycin; D010397:Penicillanic Acid; D000078142:Tazobactam; D010878:Piperacillin