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

Abstract

Staphylococcus aureus bacteremia (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. 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. Staphylococcus aureus bacteremia (SAB) is associated with significant morbidity and mortality rates. It often leads to metastatic infections that result in clinically significant complications. Bones, joints, the kidneys, and the lungs are common sites of metastatic infections (1), and SAB occasionally involves the eyes (2). Previous studies showed that the incidences of metastatic infections due to SAB range between 13% and 39% (3-10). Searching for metastatic infections in SAB is crucial, because such infections determine the duration of antibiotic therapy required and often necessitate adjuvant therapy such as drainage or surgery (11).Ocular involvement in SAB is a critical condition because it may cause vision loss. A few case series have described ocular involvement in SAB. Ness and Schneider reported on 3 patients with endogenous methicillin-resistant S. aureus (MRSA) endophthalmitis with poor prognoses (12), whereas another more recent report on 7 patients described better outcomes after treatment (13). To the best of our knowledge, however, there has been no study of the incidence, risk factors, and outcomes of ocular involvement in SAB. In addition, it has not yet been clearly determined whether clinicians should perform ophthalmic examinations for all patients with SAB. Therefore, we aimed to investigate the incidence and risk factors for ocular involvement in patients with SAB.(This study was presented in part at ICAAC/ICC 2015, San Diego, CA, 17 to 21 September 2015.) MATERIALS AND METHODSStudy design...

Infective endocarditis

“…Endophthalmitis is especially prevalent with S. aureus IE. For instance, in a prospective cohort of patients with S. aureus bacteraemia, 10 out of 23 (43%) patients who had IE also had ocular infection 91 .…”

Endocarditis and monocular blindness

“…A retrospective 10-year review identified only 28 cases with 40% of these attributable to bacteraemia from endocarditis 2. In those with Staphylococcus aureus bacteraemia and ocular involvement, infective endocarditis was found to be an independent risk factor for the development of endopthalmitis 3. The streptococcus species (as seen in this case) are the most commonly implicated bacterial pathogens, reported to cause between 30% and 50% of cases 1…”

Acute subretinal abscess inStaphylococcus aureussepticaemia with endophthalmitis showcased by multimodal retinal imaging and with 2-year follow-up

“…When SAB is associated with endophthalmitis, it is a cause for concern because it may be difficult to diagnose and challenging to manage. Four of the 15 patients with endophthalmitis associated with SAB died within 12 weeks after onset of SAB in a large single centre prospective study in South Korea 13. Subretinal abscesses have been described in association with SAB following spread from various primary sites of infection such as from vertebral osteomyelitis 14.…”