title: Human vitreous levels of selected antistaphylococcal antibiotics.
abstract: Staphylococcus epidermidis and S. aureus are the most common causes of bacterial endophthalmitis. A study of the penetration of selected antistaphylococcal antibiotics into human vitreous was undertaken in 58 patients. After 2-g intravenous doses of cephalothin, cefazolin, methicillin, oxacillin, or nafcillin were given to patients about to undergo vitreous surgery, mean vitreous levels for each antibiotic were as follows: cephalothin, 0.97 microgram/ml in diabetics and 0.69 microgram/ml in nondiabetics; cefazolin, 0.84 microgram/ml in diabetics and 1.6 microgram/ml in nondiabetics; methicillin, 2.56 micrograms/ml in diabetics and 2.64 micrograms/ml in nondiabetics; oxacillin, 0.62 microgram/ml in diabetics and 0.34 microgram/ml in nondiabetics; and nafcillin, 0.73 microgram/ml in diabetics and 0.75 microgram/ml in nondiabetics. Only cefazolin produced vitreous concentrations consistently above its minimum inhibitory concentration for 90% of S. epidermidis isolates. Staphylococcus aureus isolates were not similarly covered. There was a trend toward higher vitreous antibiotic concentrations in patients with proliferative vitreoretinopathy and rubeosis.
mesh_terms: D000900:Anti-Bacterial Agents / Q000378:metabolism* / Q000627:therapeutic use; D002437:Cefazolin / Q000378:metabolism; D002512:Cephalothin / Q000378:metabolism; D009877:Endophthalmitis / Q000209:etiology / Q000517:prevention & control; D006801:Humans; D007275:Injections, Intravenous; D008712:Methicillin / Q000378:metabolism; D009254:Nafcillin / Q000378:metabolism; D010068:Oxacillin / Q000378:metabolism; D013203:Staphylococcal Infections / Q000188:drug therapy*; D014822:Vitreous Body / Q000378:metabolism*
chemical_list: D000900:Anti-Bacterial Agents; D009254:Nafcillin; D002437:Cefazolin; D008712:Methicillin; D002512:Cephalothin; D010068:Oxacillin