title: Ophthalmic manifestations of infections caused by the USA300 clone of community-associated methicillin-resistant Staphylococcus aureus.
abstract: OBJECTIVE
  To report the microbiological, clinical, and pathological characteristics of community-associated methicillin-resistant Staphylococcus aureus (CAMRSA) infections of the eye and orbit.
  
  
  METHODS
  Prospective case series.
  
  
  METHODS
  Nine patients with CAMRSA infections of the eye and orbit were identified during a 6-month period at 2 tertiary care hospitals in San Francisco.
  
  
  METHODS
  Case identification was by prospective case selection and retrospective laboratory review of 549 MRSA cultures collected in the 2 hospitals. Ophthalmic microbial isolates were analyzed by pulsed-field gel electrophoresis and compared with a control CAMRSA clone (USA300). Clinical characteristics of patients infected with CAMRSA were reviewed, and all surgical specimens underwent pathological examination.
  
  
  METHODS
  Pulsed-field gel electrophoresis banding patterns of MRSA isolates, antibiotic sensitivity profiles, patient demographics, systemic and ocular complications of infection, and posttreatment visual acuities.
  
  
  RESULTS
  Nine ophthalmic isolates were CAMRSA clone USA300. The infections included orbital cellulitis, endogenous endophthalmitis, panophthalmitis, lid abscesses, and septic venous thrombosis. Patients were treated with trimethoprim-sulfamethoxazole, rifampin, clindamycin, or vancomycin based on microbial sensitivity studies and severity of infection. Eight of the 9 patients had no history of hospitalization. Seven patients required hospitalization, 3 required surgery, and an additional 4 required invasive procedures. Eight patients had good visual outcomes, but 1 deteriorated to no light perception. Pathological analyses showed extensive necrosis in eyelid and orbital specimens, and disorganized atrophy bulbi in an enucleated eye.
  
  
  CONCLUSIONS
  The USA300 CAMRSA clone, which carries Panton-Valentine leukocidin genes, can cause aggressive infections of the eye and orbit in hospital-naive patients. Treatment of infections often required debridement of necrotic tissues in addition to non-beta-lactam class antibiotics. In communities where CAMRSA is prevalent, ophthalmologists should obtain microbial cultures and sensitivity studies to help guide antibiotic therapy for severe ophthalmic infections.
authors.affiliation: Department of Ophthalmology, University of California San Francisco, San Francisco, California 94143-0344, USA. tinarutar@yahoo.com
authors.forename: Tina
authors.initials: T
authors.lastname: Rutar
authors.forename: Henry F
authors.initials: HF
authors.lastname: Chambers
authors.forename: J Brooks
authors.initials: JB
authors.lastname: Crawford
authors.forename: Francoise
authors.initials: F
authors.lastname: Perdreau-Remington
authors.forename: Orin M
authors.initials: OM
authors.lastname: Zwick
authors.forename: Michael
authors.initials: M
authors.lastname: Karr
authors.forename: Jennifer J
authors.initials: JJ
authors.lastname: Diehn
authors.forename: Kimberly P
authors.initials: KP
authors.lastname: Cockerham
mesh_terms: D000328:Adult; D000368:Aged; D017714:Community-Acquired Infections / Q000150:complications* / Q000382:microbiology*; D005128:Eye Diseases / Q000382:microbiology* / Q000473:pathology / Q000503:physiopathology / Q000628:therapy; D005260:Female; D006801:Humans; D008297:Male; D016106:Methicillin Resistance; D008875:Middle Aged; D011446:Prospective Studies; D013203:Staphylococcal Infections / Q000150:complications* / Q000382:microbiology*; D013211:Staphylococcus aureus / Q000235:genetics / Q000502:physiology*; D016896:Treatment Outcome