The penetration of ceftazidime into the inflamed rabbit eye

Intraocular pharmacokinetics of intravenously administered marbofloxacin in rabbits with experimentally induced acute endophthalmitis

OBJECTIVE

To compare penetration of IV administered marbofloxacin in intraocular fluids of healthy and inflamed eyes in rabbits with endotoxin-induced endophthalmitis.

ANIMALS

35 pigmented rabbits.

PROCEDURES

Endophthalmitis was induced in the right eye via intravitreal administration of Escherichia coli endotoxin. The left eye was a control eye. After 24 hours, a single dose of marbofloxacin (4 mg/kg, IV) was administered. Groups of rabbits (n = 5/group) were euthanized 0.5, 1, 2, 4, 6, 10, and 18 hours later, and blood and ocular fluids were collected. Marbofloxacin concentrations were determined via reverse-phase high-performance liquid chromatography, and pharmacokinetic analysis of the data was performed with a mono-compartmental model.

RESULTS

Mean area under the aqueous concentration-time curve was significantly lower in control eyes (1.64 +/- 0.07 microg*h/mL) than in inflamed eyes (3.31 +/- 0.11 microg*h/mL). Similarly, drug penetration into aqueous humor was 33% and 65% for control eyes and inflamed eyes, respectively. Mean area under the vitreous humor concentration-time curve for control eyes(1.75 +/- 0.05 microg*h/mL) was significantly less than for inflamed eyes (2.39 +/- 0.16 microg*h/mL). In the vitreous humor, corresponding penetrations were 34% and 47%, respectively.

CONCLUSIONS AND CLINICAL RELEVANCE

Penetration of marbofloxacin into the aqueous and vitreous humor after IV administration was significantly enhanced by intraocular inflammation, suggesting a role for this antimicrobial in the prophylaxis or treatment of bacterial endophthalmitis caused by susceptible pathogens.

Endophthalmitis

Australia and New Zealand continue to be at the forefront of endophthalmitis research. In this Clinical Controversy, an ophthalmologist from each country presents different approaches to the management of a 72-year-old patient with routine endophthalmitis following cataract surgery. Mark Elder concludes that this case needs aqueous and vitreous aspirates for culture and the initial treatment of choice is intracameral vancomycin and amikacin. The evidence for intravitreal steroids is equivocal. Systemic antibiotics are indicated if there is a possibility of a bacterial biofilm present on the intraocular lens. Nigel Morlet concludes that timely intervention with appropriate antibiotics delivered in the right concentration to the vitreous cavity is the crux of successful management of endophthalmitis. Aggressive treatment of the inflammatory response is also required to further reduce the damage to the intraocular structures. Both ophthalmologists agree that vitrectomy is not necessarily the most appropriate treatment option.

Unusual clinical presentation of Klebsiella pneumoniae induced endogenous endophthalmitis and xanthogranulomatous pyelonephritis in a non-nephrolithiasis and non-obstructive urinary tract

The genitourinary tract is well recognized as a route through which bacteria could gain access to the blood circulation. Under some circumstances, metastatic infections may occur in distant organs, including endogenous endophthalmitis. Xanthogranulomatous pyelonephritis (XGP) is an unusual variant of chronic pyelonephritis. It most often occurs in middle-aged women who frequently have a history of recurrent urinary tract infections combined with obstruction and a kidney of poor function. We reported an unusual case of urinary tract infection in a non-nephrolithiasis and non-obstructive urinary tract complicated by Klebsiella pneumoniae endogenous endophthalmitis and developed XGP in two months.

Antibiotic therapy in post-operative endophthalmitis

Endophthalmitis following routine cataract surgery is a rare but potentially devastating complication resulting in severe vision loss. Various prophylaxis treatments have been tried. However, none have been demonstrated to completely eliminate the risk. The Endophthalmitis Vitrectomy Study (EVS) helped establish clinical guidelines in the treatment of post-operative endophthalmitis in a prospective, randomized, multicenter trial. The strength and limitation of the study will be discussed as well as the current knowledge of the pharmacokinetics of intravitreous injection of antibiotics. Additionally, the common pathologic organisms, the use of antibiotic therapy, steroids, and vitrectomy will be discussed.