Endogenous endophthalmitis caused by methicillin-resistant Staphylococcus aureus (MRSA)

Endogenous Methicillin-Resistant Staphylococcus Aureus (MRSA) Endophthalmitis: A Six-year Series at a Tertiary Care Center

PURPOSE

To investigate the clinical outcomes of methicillin-resistant Staphylococcus aureus (MRSA) endophthalmitis.

METHODS

Clinical courses were reviewed for 17 eyes (15 patients) with endogenous MRSA endophthalmitis based on positive blood and vitreous culture or clinical suspicion between 2013 to 2019 at Duke University Hospitals.

RESULTS

Of 17 eyes, initial VA ranged from 20/40 to light perception. Of 15 patients, 9 had predisposing risk factors for bacteremia. All eyes received intravitreal vancomycin, 13 also received ceftazidime, and 2 also received amikacin instead of ceftazidime. Nine eyes developed retinal detachment; 6 underwent vitrectomy. Final VA ranged from 20/20 to no light perception and was ≥20/200 in 8 eyes. Eleven eyes had improved VA, 2 eyes were unchanged, and 4 were worse.

CONCLUSIONS

This study is the largest series on endogenous MRSA endophthalmitis to date. Patients had a higher proportion of final VA ≥20/200, similarly high rate of RD, and fewer enucleations compared to prior reports.

The microbiological spectrum, antimicrobial resistance pattern, and visual outcomes of endogenous endophthalmitis in West Virginia 2009-2019

PURPOSE

To report the microbiological spectrum, antimicrobial resistance patterns, and visual outcomes in patients with endogenous endophthalmitis (EE).

METHODS

This was a retrospective study of 50 patients with culture-positive EE managed in a tertiary referral center between October 2009 and 2019. Clinical, microbiology analysis, and antimicrobial resistance were reviewed. A multivariable linear regression analysis was used for identifying risk factors associated with worse visual outcomes.

RESULTS

Fifty organisms were identified, 62% bacterial and 38% fungal. The most common bacterial organism was Staphylococcus aureus (75% methicillin resistant), and Candida was the most common fungal species. Multidrug resistance was observed in methicillin-resistant Staphylococcus aureus (MRSA) isolates against clindamycin, daptomycin, and fluoroquinolones. The distributions of the final visual acuity (VA) between the bacterial and fungal groups were significantly different, and the visual outcomes in the bacterial group tended to be worse (p = 0.01). The distributions of enucleation status were significantly higher in bacterial EE (35%) than fungal EE (5.3%) (p = 0.02). Results from the multivariable linear regression analysis revealed that older age was significantly associated with worse visual outcome (coef = 0.03; p = 0.02), while fungal infections were associated with better outcomes (coef = - 0.87; p = 0.01). Intravenous drug use (coef = 0.87; p = 0.054) was a marginally significant factor associated with worse visual outcomes.

CONCLUSION

There was a higher prevalence of bacterial organisms than fungal species among EE. Bacterial EE was associated with worse visual outcomes and higher enucleation rates than fungal EE. Multidrug resistance was prevalent among MRSA isolates. Older age and intravenous drug use may be factors associated with poor prognosis.

Endogenous endophthalmitis and multifocal brain abscess-An interesting case

We present an unusual case that staphylococcal brain abscess can present in an immunocompetent with endogenous endophthalmitis secondary to a septic foci and early prevention of dissemination with appropriate management to prevent its complications.

COMMUNITY-ASSOCIATED METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS SUBRETINAL ABSCESS IN A NONBACTEREMIC PATIENT TREATED WITH INTERNAL DRAINAGE AND RETINECTOMY

PURPOSE

To report a case of community-associated methicillin-resistant Staphylococcus aureus subretinal abscess that continued to progress, despite intravitreal and systemic antibiotic therapy.

METHODS

Retrospective chart review of a 77-year-old female patient with well-controlled diabetes mellitus who developed a left eye endophthalmitis and subretinal abscess from methicillin-resistant S. aureus colonization in the absence of any systemic focus of infection.

RESULTS

The abscess and endophthalmitis resolved after the second pars plana vitrectomy that included drainage of a subretinal abscess after the failure of initial pars plana vitrectomy, and intravitreal and systemic antibiotics. Retinal detachment due to proliferative vitreoretinopathy necessitated the third pars plana vitrectomy 2 weeks after the second pars plana vitrectomy.

CONCLUSION

The authors present an unusual case of methicillin-resistant S. aureus subretinal abscess in a patient with methicillin-resistant S. aureus colonization with negative blood, aqueous humor culture, and vitreous culture but a positive culture from subretinal aspirate.

Multimodal ophthalmic imaging of staphylococcus aureus bacteremia associated with chorioretinitis, endocarditis, and multifocal brain abscesses

PURPOSE

Staphylococcus aureus bacteriemia (SAB) as critical condition for the life and occasionally involves the eyes. The aim of this report is to describe the ocular involvement with multimodal imaging.

OBSERVATIONS

A patient admitted for evaluation of acute onset of confusion, disorientation, and generalized malaise and found to have methicillin-resistant staphylococcus aureus (MRSA)-associated endocarditis and multifocal brain abscesses was evaluated by the ophthalmology service. The patient's visual acuity was 20/20 OU without relative afferent pupillary defect and normal intraocular pressures. Bedside anterior segment examination was normal. Posterior segment examination revealed intraretinal hemorrhages and Roth spots in the posterior pole of the right eye, and two deep well-defined focal white chorioretinal infiltrates and a hemorrhagic pigment epithelium detachment in the temporal quadrant of the left eye. Multimodal imaging was utilized to document these findings and ensure adequate antibiotic therapy.

CONCLUSION

SAB has the potential for poor visual outcomes as well as significant morbidity and mortality. Multimodal imaging of SAB-related chorioretinitis allows for accurate diagnosis as well as assessment of response to antimicrobial therapy.

Metastatic Endogenous Endophthalmitis: A Rare Presentation with Methicillin-resistant Staphylococcus aureus Prostatic Abscess

A 62-year-old male with the previous history of uncontrolled diabetes and hypertension on irregular treatment presented with a history of fever, dysuria, and urinary retention with progressive painful loss of vision over a period of 2 days. His eye examination showed hypopyon, and he was diagnosed to have rapidly progressive endogenous endophthalmitis. He was started on vancomycin and piperacillin-tazobactam empirically. His blood and urine cultures grew methicillin-resistant Staphylococcus aureus (MRSA). Transesophageal echocardiography ruled out infective endocarditis. Intravitreal injection of vancomycin and ceftazidime was given. Vitreous culture also grew MRSA. A workup for possible source revealed multiple prostatic abscesses on the transrectal ultrasound. Antibiotic was changed to daptomycin in view of high vancomycin minimum inhibitory concentration. His vision was improved at the time of discharge.

Incidence and Risk Factors of Ocular Infection Caused by Staphylococcus aureus Bacteremia

Staphylococcus aureusbacteremia (SAB) often leads to ocular infections, including endophthalmitis and chorioretinitis. However, the incidence, risk factors, and outcomes of ocular infections complicated by SAB are largely unknown. We retrospectively analyzed the incidence and risk factors of ocular involvement in a prospective cohort of patients with SAB at a tertiary-care hospital. Ophthalmologists reviewed the fundoscopic findings and classified the ocular infections as endophthalmitis or chorioretinitis. During the 5-year study period, 1,109 patients had SAB, and data for 612 (55%) who underwent ophthalmic examinations within 14 days after SAB onset were analyzed. Of those 612 patients, 56 (9% [95% confidence interval [CI], 7 to 12%]) had ocular involvement, including 15 (2.5%) with endophthalmitis and 41 (6.7%) with chorioretinitis. In a multivariate analysis, infective endocarditis (adjusted odds ratio [aOR], 5.74 [95% CI, 2.25 to 14.64]) and metastatic infection (aOR, 2.38 [95% CI, 1.29 to 4.39]) were independent risk factors for ocular involvement. Of the 47 patients with ocular involvement who could communicate, only 17 (36%) had visual disturbances. Two-thirds of the patients with endophthalmitis (10/15 patients) were treated with intravitreal antibiotics combined with parenteral antibiotics, whereas all of the patients with chorioretinitis were treated only with systemic antibiotics. No patients became blind. Among 42 patients for whom follow-up assessments were available, the ocular lesions improved in 29 (69%) but remained the same in the others. Ocular involvement was independently associated with death within 30 days after SAB onset. Ocular involvement is not uncommon among patients with SAB. Routine ophthalmic examinations should be considered for patients with infective endocarditis or metastatic infections caused by SAB.

Blood-Retinal Barrier Compromise and Endogenous Staphylococcus aureus Endophthalmitis

PURPOSE

To test the hypothesis that blood-retinal barrier compromise is associated with the development of endogenous Staphylococcus aureus endophthalmitis.

METHODS

To compromise the blood-retinal barrier in vivo, streptozotocin-induced diabetes was induced in C57BL/6J mice for 1, 3, or 5 months. Diabetic and age-matched nondiabetic mice were intravenously injected with 108 colony-forming units (cfu) of S. aureus, a common cause of endogenous endophthalmitis in diabetics. After 4 days post infection, electroretinography, histology, and bacterial counts were performed. Staphylococcus aureus-induced alterations in in vitro retinal pigment epithelial (RPE) cell barrier structure and function were assessed by anti-ZO-1 immunohistochemistry, FITC-dextran conjugate diffusion, and bacterial transmigration assays.

RESULTS

We observed one bilateral infection in a control, nondiabetic animal (mean = 1.54 × 103 ± 1.78 × 10² cfu/eye, 7% incidence). Among the 1-month diabetic mice, we observed culture-confirmed unilateral infections in two animals (mean = 5.54 × 10² ± 7.09 × 10² cfu/eye, 12% incidence). Among the 3-month diabetic mice, infections were observed in 11 animals, three with bilateral infections (mean = 2.67 × 10² ± 2.49 × 10² cfu/eye, 58% incidence). Among the 5-month diabetic mice, we observed infections in five animals (mean = 7.88 × 10² ± 1.08 × 10³ cfu/eye, 33% incidence). In vitro, S. aureus infection reduced ZO-1 immunostaining and disrupted the barrier function of cultured RPE cells, resulting in diffusion of fluorophore-conjugated dextrans and transmigration of live bacteria across a permeabilized RPE barrier.

CONCLUSIONS

Taken together, these results indicated that S. aureus is capable of inducing blood-retinal barrier permeability and causing endogenous bacterial endophthalmitis in normal and diabetic animals.

Endogenous endophthalmitis: diagnosis, management, and prognosis

Endogenous endophthalmitis is an ophthalmic emergency that can have severe sight-threatening complications. It is often a diagnostic challenge because it can manifest at any age and is associated with a number of underlying predisposing factors. Microorganisms associated with this condition vary along a broad spectrum. Depending upon the severity of the disease, both medical and surgical interventions may be employed. Due to rarity of the disease, there are no guidelines in literature for optimal management of these patients. In this review, treatment guidelines based on clinical data and microorganism profile have been proposed.

An eleven-year retrospective study of endogenous bacterial endophthalmitis

Purpose. To determine the clinical features, microbial profiles, treatment outcomes, and prognostic factors for endogenous bacterial endophthalmitis (EBE). Methods. The medical records of 27 eyes of 21 patients diagnosed with EBE for 11 years were reviewed. Collected data included age, site of infection, visual acuities (VAs), microbial profiles, and treatment regimen. Results. The mean age was 68.5 years. Gram-positive organisms accounted for 76.2%, while gram-negative ones accounted for 19.0%. Staphylococcus aureus was the most common causative organism (52.3%) of which 72.7% was methicillin-resistant S. aureus. A final VA of ≥20/40 was achieved in 44% and 20/200 or better was in 64%. Eyes with initial VA of ≥20/200 (P = 0.003) and focal involvements (P = 0.011) had significantly better final VA. Initial VA (P = 0.001) and the interval between onset of ocular symptoms and intravitreal antibiotic injection (P = 0.097) were associated with final VA in eyes receiving intravitreal antibiotics. Conclusions. EBE is generally associated with poor visual outcome; however the prognosis may depend on initial VA, extent of ocular involvement, and an interval between onset of ocular symptoms and intravitreal antibiotic injection. Early diagnosis and early intravitreal injection supplement to systemic antibiotics might lead to a relatively good visual outcome.

Intraocular penetration of systemic antibiotics in eyes with penetrating ocular injury

PURPOSE

To determine whether penetrating scleral or corneal injury can enhance intraocular penetration of systemic moxifloxacin, vancomycin, and ceftazidime.

METHODS

Thirty rabbits were divided into 3 groups for each antibiotic and then further subdivided to receive either scleral or corneal injury to the right eye. The left eye served as a control. Intravenous antibiotics were given following injury, and eyes were subsequently enucleated. Vitreous antibiotic concentration was determined by high-performance liquid chromatography analysis. Plasma concentration was measured for comparison.

RESULTS

Intravitreal moxifloxacin concentration was unchanged by injury. Minimum inhibitory concentration (MIC90) was achieved in the vitreous against the most common gram-positive endophthalmitis-causing organisms. Intravitreal vancomycin levels were not enhanced by injury and did not reach the MIC90 for gram-positive organisms commonly causing intraocular infection. Intravitreal ceftazidime was increased in the injured eyes, 67% and 73% higher in scleral and corneal injury eyes. It reached MIC90 of many gram-negative bacteria.

CONCLUSIONS

Intravitreal antibiotic penetration of systemic antibiotics with or without penetrating ocular injury varies depending on the antibiotic. For prevention or treatment of gram-positive-bacteria-causing endophthalmitis, intravitreal vancomycin is necessary and provides the most reliable coverage. Systemic ceftazidime can be used for many gram-negative bacteria, but intravitreal injection is recommended for better coverage, especially for more-potent organisms. Systemic moxifloxacin can be considered for most gram-positive and -negative infections due to its excellent intraocular penetration and broad coverage, but the patient's previous history of its topical use and increasing resistance patterns must be considered.

Toll-like receptor 2 ligand pretreatment attenuates retinal microglial inflammatory response but enhances phagocytic activity toward Staphylococcus aureus

Staphylococcus aureus is a leading cause of severe endophthalmitis, which often results in vision loss in some patients. Previously, we showed that Toll-like receptor 2 (TLR2) ligand pretreatment prevented the development of staphylococcal endophthalmitis in mice and suggested that microglia might be involved in this protective effect (Kumar A, Singh CN, Glybina IV, Mahmoud TH, Yu FS. J. Infect. Dis. 201:255-263, 2010). The aim of the present study was to understand how microglial innate response is modulated by TLR2 ligand pretreatment. Here, we demonstrate that S. aureus infection increased the CD11b(+) CD45(+) microglial/macrophage population in the C57BL/6 mouse retina. Using cultured primary retinal microglia and a murine microglial cell line (BV-2), we found that these cells express TLR2 and that its expression is increased upon stimulation with bacteria or an exclusive TLR2 ligand, Pam3Cys. Furthermore, challenge of primary retinal microglia with S. aureus and its cell wall components peptidoglycan (PGN) and lipoteichoic acid (LTA) induced the secretion of proinflammatory mediators (tumor necrosis factor alpha [TNF-α] and MIP-2). This innate response was attenuated by a function-blocking anti-TLR2 antibody or by small interfering RNA (siRNA) knockdown of TLR2. In order to assess the modulation of the innate response, microglia were pretreated with a low dose (0.1 or 1 μg/ml) of Pam3Cys and then challenged with live S. aureus. Our data showed that S. aureus-induced production of proinflammatory mediators is dramatically reduced in pretreated microglia. Importantly, microglia pretreated with the TLR2 agonist phagocytosed significantly more bacteria than unstimulated cells. Together, our data suggest that TLR2 plays an important role in retinal microglial innate response to S. aureus, and its sensitization inhibits inflammatory response while enhancing phagocytic activity.

Endogenous methicillin-resistant Staphylococcus aureus endophthalmitis

PURPOSE

To report on the presentation, treatment, and outcomes of the largest series to date for patients with endogenous methicillin-resistant Staphylococcus aureus endophthalmitis at a single institution and compare the results from previously published reports of this disease entity.

METHODS

Retrospective, noncomparative, consecutive case series of patients who were treated for endogenous methicillin-resistant S. aureus endophthalmitis from a single tertiary referral institution were reviewed.

RESULTS

Eight eyes of seven consecutive patients, with a mean age of 58.1 years, were diagnosed with culture-proven endogenous methicillin-resistant S. aureus endophthalmitis. Five patients were male, and six patients had a unilateral presentation. Five of eight eyes were treated with initial vitreous tap and injection of antibiotics, and six eyes showed a retinal detachment during the course of treatment. Final visual acuity ranged from 20/40 to no light perception, and 5 of 8 eyes showed improvement in visual acuity from initial presentation. Only one eye became blind and painful and required enucleation.

CONCLUSION

This series represents the largest single-institution report on endogenous methicillin-resistant S. aureus endophthalmitis and associated outcomes. Although previously reported cases cited poor visual outcomes and high enucleation rates, the authors' current series shows that retinal detachments are common and enucleation rates are low.

Presence of adequate intravitreal concentrations of daptomycin after systemic intravenous administration in a patient with endogenous endophthalmitis

STUDY OBJECTIVE

To determine whether daptomycin has the potential to be an effective alternative treatment to vancomycin for methicillin-resistant Staphylococcus aureus (MRSA) endogenous endophthalmitis by measuring daptomycin penetration into the vitreous humor.

DESIGN

Laboratory analysis of serum and intravitreal fluids to quantify the ratio between vitreous humor and serum daptomycin concentrations.

SETTING

Critical care unit in a university-affiliated tertiary care medical center.

PATIENT

A 53-year-old woman treated with intravenous daptomycin for MRSA bacteremia, endophthalmitis, and pericarditis.

MEASUREMENTS AND MAIN RESULTS

After the first dose of intravenous daptomycin 10 mg/kg was administered to the patient, serum and intravitreal fluids were analyzed by using high-performance liquid chromatography to determine daptomycin concentrations; pericardial fluid was also analyzed to determine whether adequate levels were present in actively infected tissue. A vitreous concentration of approximately 28% of the serum concentration was achieved. Although therapeutic efficacy could not be assessed in the absence of intraocular cultures, the presence of adequate drug concentrations in the vitreous humor is promising. Ophthalmic infections caused by resistant isolates continue to increase, and effective alternatives to vancomycin, the standard of care, are needed. For endogenous endophthalmitis, these alternative therapies will need to reach therapeutic concentrations in the vitreous humor and adequately penetrate the terminal source of infection. In this analysis, the intravitreal concentration of daptomycin was comparable to concentrations previously reported with vancomycin; thus daptomcyin may be an attractive option when vancomycin therapy fails or is contraindicated. To our knowledge, this is the first report of intravitreal daptomycin concentrations measured in a patient receiving intravenous daptomycin.

CONCLUSION

Adequate concentrations of daptomycin were achieved in the vitreous fluid after a single systemic dose of the drug. Daptomycin may be an effective alternative to vancomycin in patients with ophthalmic infections. Future clinical studies comparing daptomycin with vancomycin in this clinical setting are warranted.

[Multiresistant bacteria in ophthalmology]

Multidrug-resistant bacteria have emerged as an increasing threat in many areas of medicine. The most prominent multidrug-resistant pathogens are methicillin-resistant S. aureus (MRSA), vancomycin-resistant MRSA (VMRSA), vancomycin-resistant enterococci (VRE), and Enterobacteriaceae with extended-spectrum beta-lactamase (ESBL). In particular, MRSA and VRE cause infections seen in ophthalmology. The lids, lacrimal duct, and ocular surface are frequently involved.

Staphylococcus aureus endophthalmitis: antibiotic susceptibilities, methicillin resistance, and clinical outcomes

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.