Periorbital infections secondary to methicillin-resistant Staphylococcus aureus

June 1, 2007

Philadelphia-The prevalence of periorbital soft-tissue infections has been increasing due to methicillin-resistant Staphylococcus aureus (MRSA), and many of these infections are occurring in non-hospitalized patients. Due to the high suspicion for MRSA in periorbital infections, clinicians should know their community resistance profiles and be prepared to perform appropriate surgical or medical interventions, said Brett A. Levinson, MD.

Philadelphia-The prevalence of periorbital soft-tissue infections has been increasing due to methicillin-resistant Staphylococcus aureus (MRSA), and many of these infections are occurring in non-hospitalized patients. Due to the high suspicion for MRSA in periorbital infections, clinicians should know their community resistance profiles and be prepared to perform appropriate surgical or medical interventions, said Brett A. Levinson, MD.

Dr. Levinson, a fellow in the cornea service at Wills Eye at Jefferson, Philadelphia, presented findings from a small retrospective study at the American Academy of Ophthalmology annual meeting. The senior author of the study was Sajeev S. Kathuria, MD, FACS, director of oculoplastics service, University of Maryland, Baltimore.

The authors conducted a retrospective review of charts from February 2004 to February 2006 at the University of Maryland Medical Center and the Baltimore Veterans Affairs Medical Center. The review included all patients with periorbital infections seen by the eye service. This included eight female and seven male patients ranging in age from 17 months to 86 years (mean, 43.5 years); all had been admitted and treated as inpatients after presenting to the eye service.

Culture results showed that 73% (n = 11) of patients had an MRSA infection; two had a methicillin-sensitive S aureus (MSSA) infection, and the cause was unknown in the remaining two patients.

Lid/brow was the most common site of infection in all patients. Among those with an MRSA infection, eight had lid or brow abscesses, one had panophthalmitis as well as a lid abscess, one had a lacrimal gland abscess, and one had an infected orbital implant.

One of the patients with MSSA had a lid or brow abscess and one had a subperiosteal abscess. Both patients with an unknown cause of infection had lid or brow abscesses.

Irrigation and debridement (I/D) was the most commonly used management approach for patients with MRSA and was performed on eight individuals, Dr. Levinson reported. One patient underwent enucleation, one underwent explantation of an orbital implant, and one received medical treatment only. One MSSA patient underwent I/D and one had medical therapy; both patients with unknown cultures had I/D.

Dr. Levinson and his colleagues identified several risk factors for MRSA, and some patients had more than one of these risk factors. Five patients had abused intravenous drugs, four had histories of incarceration, three had been hospitalized or had prior surgery, two had HIV, and one had a close contact with MRSA.

MRSA was classified as health care-associated in the study if the culture was identified after 48 hours of admission; the patient had been hospitalized, had surgery or dialysis, or had been in long-term care within 1 year of the culture; or the patient had a permanent indwelling catheter or a known prior positive MRSA culture.

Community-associated cases of MRSA were those that did not have any of the above-mentioned features.

With these definitions, six cases of hospital-associated MRSA were identified, including two with prior surgery and four with prior hospitalization. Five cases were community-associated.

Sensitivity testing in the health care-associated cases revealed that the bacteria in one or more patients were resistant to several antibiotics, including erythromycin, tetracycline, clindamycin, and gatifloxacin. All of the bacteria samples from patients with community-associated MRSA infections were resistant to erythromycin and gatifloxacin; cultures from one patient were resistant to tetracycline.

Initial antibiotic management consisted of vancomycin for seven patients, cephalexin for one, vancomycin plus ampicillin-sulbactam for one patient, and clindamycin plus ampicillin-sulbactam in two cases.

The final antibiotic management at the time of discharge varied. Four patients were treated with vancomycin, two with trimethoprim-sulfamethoxazole, two with clindamycin, and one each with levofloxacin, gatifloxacin, or linezolid.OT