Avastin/Lucentis Update 49: A Follow-up on Infections from Intravitreal Injections
Posted Sep 13 2011 11:30am
In my last posting ( Avastin/Lucentis Update 48 ), I wrote about the problems with Avastin injections, that appeared to be caused by non-sterile/non-aseptic techniques during re-packaging Avastin from 4 ml bottles into much smaller doses (0.05ml) in tuberculin syringes.
A colleague, who is a compounding pharmacist, pointed out to me that other things can cause contamination of the eye during intravitreal injections besides using non-aseptic techniques during aliquoting and re-packaging of Avastin into injectable syringes.
He sent me a copy of a report from Medscape Medical News that was published online following a meeting of the American Academy of Ophthalmology and Middle East Africa Council of Ophthalmology 2010 Joint Annual Meeting, held during last year’s AAO Meeting.
Here are excerpts from that report:
Intravitreal Injections Expose Patients to Streptococcus More Often Than Eye Surgery
Kathleen Louden October 20, 2010 Medscape Medical News
Streptococcus is isolated much more frequently from endophthalmitis cultures after intravitreal injection (IVI) of antivascular endothelial growth-factor agents than after ocular surgery, results of a meta-analysis show.
Ophthalmologists should consider using additional sterile techniques during these injections to prevent exposing patients to the sight-threatening complication of streptococcal endophthalmitis, said study author Colin McCannel, MD, associate professor of ophthalmology from the Jules Stein Eye Institute at the University of California at Los Angeles.
"If we can prevent some of the worst cases of endophthalmitis, I think it's worth the effort," Dr. McCannel told Medscape Medical News.
To confirm his impression that reports of Streptococcus organisms seemed more frequent than should be expected after IVI, Dr. McCannel analyzed the American medical literature from 2005 through 2009. He found 16 articles that reported the causative organism in post-IVI endophthalmitis. As expected, endophthalmitis was rare, occurring in 54 of 105,531 injections. Only 26 were culture-positive, according to the abstract. Most of the causative organisms were coagulase-negative Staphylococcus, he said.
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
This finding led him, he said during an interview, to do "some detective work" to try to find the possible source of these streptococcal infections. 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."
If other studies validate his findings, the ophthalmic community should decide whether to recommend wearing a surgical mask during IVI, he said. He told the audience that he does not wear a mask because "it would be burdensome to take it on and off" during the brief injections.
Another precautionary strategy that Dr. McCannel suggested was to avoid talking, coughing, or sneezing during the injections. He said he asks his ophthalmic technicians to instruct the patient before the procedure that "the injection is not the time to ask questions" and to refrain from talking. If he needs to instruct the patient, he said he speaks away from the patient.
A panelist at the session who did not participate in the study, Joan W. Miller, MD, said in an interview that the study findings have the potential to change clinical practice. Dr. Miller, professor and chair of ophthalmology at Harvard Medical School in Boston, Massachusetts, said she will consider changing her IVI techniques to try to prevent the spread of Streptococcus.
"Not talking on the [injection] field is probably sufficient precaution," she told Medscape Medical News.
My friend, the compounding pharmacist, went on to say, “I wish we had more visibility into what [really] happened in TN and FL and the pharmacies that prepared those compounds. It is even more critical that physicians look to do their diligence when choosing a pharmacy to provide these sterile compounds to patients. Because of our strict quality control and assurance procedures we have created an environment that focuses on quality.”
“As you may be aware OMIC, the ophthalmology insurance carrier, has been recommending to physicians that the best practice is to seek out compounding pharmacies that have been accredited by PCAB, the Pharmacy Compounding Accreditation Board. Being accredited by PCAB gives confidence to physicians and consumers that products are prepared in accordance with the United States Pharmacopeial Convention's standards. Chapter 797 of the USP clearly outlines the facility, environment and testing necessary to provide sterile compounded products. Without an accreditation body like PCAB, there is no reliable third-party verification that a pharmacy meets the USP 797 standard.”