Talking May Increase the Risk of Streptococcal Infections after Intravitreal Injections

Dr. McCannel from UCLA presented an interesting paper at the annual meeting of American Academy of Ophthalmology in Chicago in October, 2010. He analyzed 16 articles published in the American medical literature from 2005 through 2009 on the topic of endophthalmitis (infection inside the eye) following intravitreal injections. As expected, endophthalmitis was rare, occurring in 54 of 105,531 injections. Only 26 were culture-positive, giving an incidence of 0.024%.

However, cultures yielded Streptococcus organisms 30.8% of the time (8 of 26), which Dr. McCannel said is "3- or 4-fold higher" than the incidence reported in the literature for acute postoperative endophthalmitis. The postoperative incidence of streptococcal endophthalmitis ranges from 0% after vitrectomy to 8.2% to 9% after cataract surgery, he reported.

Likely Source of Infection:

He found several studies in the anesthesia literature reporting streptococcal meningitis after dural puncture, a procedure that, according to Dr. McCannel, has a working distance between physician and patient similar to that of IVI. Analysis found that the causative organisms in most of those cases came from the treating physician's oral flora, which was aerosolized during talking.

Consequently, the Centers for Disease Control and Prevention in Atlanta, Georgia, recommended in 2007 that spinal procedure operators wear a surgical mask during the procedure (MMWR Morb Mortal Wkly Rep.2010;59:65-69).

Ophthalmologists "often have to give directions to the patient during injections, and sometimes there is small talk," Dr. McCannel said. "The patient's eye is probably being showered with these microscopic droplets. We may be contaminating the injection field or the needle.

Implications of the Study

1. Endophthalmitis is rare occurrence after intravitreal injections, which are commonly performed for age-related macular degeneration, diabetic macular edema, retinal vein occlusion and other conditions.
2. Streptococcal infections are more common after intravitreal injections compared to other intraocular procedures. Mouth is an important reservoir of streptococci.
   
3. Talking, coughing and sneezing should be minimized after the lid speculum has been placed to open the eye prior to administration of intravitreal injections.
4. If a surgeon needs to talk to the patient while administering intravitreal injections, he should turn his face away from the surgical field.
5. Although wearing a mask appears to be a good idea, it is not commonly done, including by the author of the study mentioned.
6. A surgeon should, however, be aware of the possibility of contamination of surgical field by talking, and should take steps to minimize it.