From Doheny Eye Institute (AHK), Keck School of Medicine, University of Southern California, Los Angeles, California; and the Department of Ophthalmology (DE), Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts.
The authors have no financial or proprietary interest in the materials presented herein.
Address correspondence to Dean Eliott, MD, Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, 243 Charles Street, Boston, MA 02114. E-mail: Dean_Eliott@meei.harvard.edu
Klebsiella pneumoniae has been recognized as an emerging and rapidly growing cause of endogenous endophthalmitis in the Asian population.1–4 Recent evidence suggests that the K1 capsular phenotype of the Klebsiella organism may be an important risk factor for the development of endogenous endophthalmitis in patients with non-ocular foci of infection.5
We report the case of a woman with bilateral endophthalmitis as the presenting manifestation of disseminated K. pneumoniae infection with multiorgan involvement. To our knowledge, this is the first proven case of the K. pneumoniae K1 capsular phenotype reported in the United States.
A 51-year-old Chinese woman with bilateral vision loss over 3 to 4 weeks was referred to the Doheny Retina Institute. The patient complained of bilateral ocular pain, severe photophobia, and swollen eyelids worsening over the previous week. Review of systems revealed 1 to 2 weeks of malaise, productive cough, subjective fevers, and night sweats. The patient denied any other systemic symptoms and denied any medical history or medications. She was originally from China but had lived in the Los Angeles area for the past 8 years and had not traveled to China during this time. There was no history of smoking, alcohol, illicit drugs, pets, or sick contacts. Family history was unremarkable.
External examination revealed severe bilateral conjunctival edema (Fig. 1). Visual acuity was bare light perception in both eyes. Pupils were dilated and unreactive. Intraocular pressure was 21 mm Hg in both eyes. Slit-lamp examination revealed severe chemosis and injection in both eyes. Both corneas were edematous and there was 3+ cell and flare bilaterally, but no hypopyon. The vitreous was hazy with no view to the posterior pole in either eye. B-scan ultrasonography revealed diffuse and dense bilateral vitreous opacities. Bilateral endogenous endophthalmitis was suspected and the patient underwent bilateral aqueous paracentesis and vitreous aspirates, and she received bilateral intravitreal injections of vancomycin (1 mg/0.1 cc), ceftazidime (2.25 mg/0.1 cc) and voriconazole (100 μg/0.1 cc). The patient was then admitted to the hospital for further evaluation.
Figure 1. External Examination of the Right Eye (A) and Left Eye (B) Revealed Significant Conjunctival Chemosis and Injection. No Hypopyon Was Notable on Gross or Slit-Lamp Examination.
Computed tomography studies showed left-sided pneumonia (Fig. 2), two hypodense foci in the brain suggestive of abscesses (Fig. 3), and several hypodense liver lesions suggestive of abscesses (Fig. 4). Transesophageal echocardiography revealed cardiac valvular vegetations consistent with endocarditis. The patient received systemic broad spectrum antimicrobial therapy including cefotaxime, gentamicin, and voriconazole. Anterior chamber fluid cultures, vitreous cultures, and blood and urine cultures were ultimately positive for K. pneumoniae (K1 serotype) that was resistant to penicillin (minimum inhibitory concentration [MIC] ≥ 32) but otherwise sensitive to ampicillin-sulbactam (MIC = 8), aztreonam (MIC ≤ 8), cefazolin (MIC ≤ 8), gentamicin (MIC ≤ 0.5), levofloxacin (MIC ≤ 1), piperacillin-tazobactam (MIC ≤ 8), tobramycin (MIC ≤ 0.5), and trimethoprim-sulfamethoxazole (MIC ≤ 10).
Figure 2. Computed Tomography Scan of the Chest Showing Lungs with Left Lower Lobe Consolidation and Loculated Fluid (star).
Figure 3. Computed Tomography Scan of the Head Showing Contrast Enhancing Ring Lesion Consistent with an Abscess (arrowhead).
Figure 4. Computed Tomography Scan of the Abdomen Showing Small Ring Enhancing Lesion Consistent with Liver Abscess (arrowhead).
Visual acuity progressed to no light perception in both eyes and the patient was discharged approximately 2 weeks later to a nursing facility with a several-week course of ceftriaxone and gentamicin. At the 6-month follow-up visit, the patient was systemically asymptomatic but still had no light perception in both eyes.
We describe a patient with bilateral K. pneumoniae endogenous endophthalmitis who was found to have disseminated infection. This case is notable because of the severe, yet largely asymptomatic, burden of disease in a patient who had not traveled outside the United States for many years. Our review of the literature shows that no cases of Klebsiella endophthalmitis with verified K1 serotype have been reported in the United States. It should be noted that previous cases may not have been serotyped due to lack of an appropriate assay for this organism.
Although the exact source of Klebsiella endophthalmitis is not clear in this case, it is mainly thought to occur secondary to hematogenous spread from the liver and is rarely associated with surgery or trauma.6 The Endophthalmitis Vitrectomy Study reports that only 5.9% of culture-positive cases were due to gram-negative organisms, and none of these were due to Klebsiella.7
The increased incidence of endogenous endophthalmitis suggests that some Klebsiella organisms may have virulence factors that predispose to penetration of the blood–ocular barrier and supports the observation that patients usually have compromised immunity. Interestingly, organisms with capsule serotypes K1 or K2 seem to predominate in cases of endogenous endophthalmitis.5 In vitro assays show that capsular serotypes K1 and K2 inhibit phagocytosis by neutrophils and therefore may blunt the host immune response to these organisms.8
Patients with liver abscess and immunocompromising conditions should be carefully monitored for hematologic spread and endogenous endophthalmitis. Patients of Asian descent are at highest risk for endogenous endophthalmitis related to K. pneumoniae. It is not clear whether this is due to a genetic predisposition to infection among Asians or just a higher prevalence of virulent organisms in Asia. It is striking that our patient had lived in the United States for 8 years without any travel back to China and still developed this disseminated systemic disease.
- Wong JS, Chan TK, Lee HM, Chee SP. Endogenous bacterial endophthalmitis: an east Asian experience and a reappraisal of a severe ocular affliction. Ophthalmology. 2000;107:1483–1491. doi:10.1016/S0161-6420(00)00216-5 [CrossRef]
- Sng CC, Jap A, Chan YH, Chee SP. Risk factors for endogenous Klebsiella endophthalmitis in patients with Klebsiella bacteraemia: a case-control study. Br J Ophthalmol. 2008;92:673–677. doi:10.1136/bjo.2007.132522 [CrossRef]
- Chen YJ, Kuo HK, Wu PC, et al. A 10-year comparison of endogenous endophthalmitis outcomes: an east Asian experience with Klebsiella pneumoniae infection. Retina. 2004;24:383–390. doi:10.1097/00006982-200406000-00008 [CrossRef]
- Yang CS, Tsai HY, Sung CS, Lin KH, Lee FL, Hsu WM. Endogenous Klebsiella endophthalmitis associated with pyogenic liver abscess. Ophthalmology. 2007;114:876–880. doi:10.1016/j.ophtha.2006.12.035 [CrossRef]
- Fang CT, Lai SY, Yi WC, Hsueh PR, Liu KL, Chang SC. Klebsiella pneumoniae genotype K1: an emerging pathogen that causes septic ocular or central nervous system complications from pyogenic liver abscess. Clin Infect Dis. 2007;45:284–293. doi:10.1086/519262 [CrossRef]
- Scott IU, Matharoo N, Flynn HW Jr, Miller D. Endophthalmitis caused by Klebsiella species. Am J Ophthalmol. 2004;138:662–663. doi:10.1016/j.ajo.2004.04.051 [CrossRef]
- Forster RK. The Endophthalmitis Vitrectomy Study. Arch Ophthalmol. 1995;113:1555–1557.
- Lin JC, Siu LK, Fung CP, et al. Impaired phagocytosis of capsular serotypes K1 or K2 Klebsiella pneumoniae in type 2 diabetes mellitus patients with poor glycemic control. J Clin Endocrinol Metab. 2006;91:3084–3087. doi:10.1210/jc.2005-2749 [CrossRef]