Elsevier

American Journal of Ophthalmology

Volume 149, Issue 2, 1 February 2010, Pages 278-283.e1
American Journal of Ophthalmology

Original article
Staphylococcus aureus Endophthalmitis: Antibiotic Susceptibilities, Methicillin Resistance, and Clinical Outcomes

https://doi.org/10.1016/j.ajo.2009.08.023Get rights and content

Purpose

To investigate the antibiotic susceptibility and clinical outcomes of endophthalmitis caused by methicillin-sensitive Staphylococcus aureus (MSSA) versus methicillin-resistant (MRSA) S. aureus.

Design

Retrospective, consecutive case series.

Methods

Charts of 32 patients with culture-proven S. aureus endophthalmitis seen at the Bascom Palmer Eye Institute from January 1, 1995, through January 1, 2008, were reviewed. Antibiotic susceptibility profiles, identified using standard microbiologic protocols, and visual acuity at 1 and 3 months were the main outcome measures.

Results

MSSA was recovered from 19 (59%) of 32 patients and MRSA was recovered from 13 (41%) of 32 patients. Causes included cataract surgery in 18 (56%) of 32 patients, endogenous in 5 (16%) of 32 patients, bleb association in 4 (13%) of 32 patients, pars plana vitrectomy and ganciclovir implantation in 3 (9%) of 32 patients, and trauma in 2 (6%) of 32 patients. All isolates were sensitive to vancomycin. MSSA isolates were sensitive to all tested antibiotics, except one that exhibited fluoroquinolone resistance. In the MRSA group, frequent resistance occurred with the fourth-generation fluoroquinolones (moxifloxacin, 5 of 13 patients [38%]; gatifloxacin, 5 of 13 patients [38%]). The median presenting visual acuity was approximately hand movements for both MSSA and MRSA eyes. All eyes received intravitreal antibiotics. Pars plana vitrectomy was performed on 47% of MSSA and 61% of MRSA patients. A final visual acuity of 20/400 or better at 3 months was achieved in 59% of MSSA and 36% of MRSA patients (P = .5).

Conclusions

Although all MSSA and MRSA isolates were sensitive to vancomycin, fewer than half of MRSA isolates were sensitive to the fourth-generation fluoroquinolones. Visual acuity outcomes between MRSA and MSSA eyes were not significantly different.

Section snippets

Methods

A computer search of the Bascom Palmer Eye Institute Microbiology Department data base and corresponding medical records identified 32 cases of patients with S. aureus endophthalmitis between January 1, 1995, and January 1, 2008.

Treatments consisted of either tap and inject, that is, aspiration of a vitreous specimen with subsequent injection of antibiotics (vancomycin 1.0 mg and ceftazidime 2.25 mg) or pars plana vitrectomy with subsequent injection of the same antibiotics. Treatment was at

Results

Thirty-two cases of endophthalmitis resulting from S. aureus were identified, including 13 (41%) caused by MRSA and 19 (59%) caused by MSSA. Men and women were distributed equally in both the MRSA and the MSSA group (7 men and 6 women in the MRSA group, 9 men and 10 women in the MSSA group). Also, there was no difference in age between the 2 groups, with a mean age of 66 years in the MRSA group and of 67 years in the MSSA group.

Overall, most endophthalmitis cases caused by S. aureus (18 of 32

Discussion

The current study of 32 patients represents the largest reported clinical case series of S. aureus endophthalmitis (Table 3). In the EVS reports of acute-onset endophthalmitis associated with cataract or secondary intraocular lens implantation, S. aureus was the second most common organism after coagulase-negative staphylococci. In the 30 EVS patients with S. aureus, less than 20/100 vision was found in half of the patients.15

Over the current study period from 1995 through 2008, MRSA accounted

James C. Major, Jr. received his undergraduate degree in Biology from Emory University and Masters and Doctor of Philosophy in Biology at The University of Texas at Austin. Thereafter, he received his medical degree from Baylor College of Medicine. Dr. Major completed his ophthalmology residency, vitreoretinal fellowship, and Chief Residency at the Bascom Palmer Eye Institute in Miami. He served on the faculty at three institutions. He currently is practicing with Retina Consultants of Houston.

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    James C. Major, Jr. received his undergraduate degree in Biology from Emory University and Masters and Doctor of Philosophy in Biology at The University of Texas at Austin. Thereafter, he received his medical degree from Baylor College of Medicine. Dr. Major completed his ophthalmology residency, vitreoretinal fellowship, and Chief Residency at the Bascom Palmer Eye Institute in Miami. He served on the faculty at three institutions. He currently is practicing with Retina Consultants of Houston.

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