Purpose
To culture and examine possible sources of bacterial contamination of needles from multiple punctures and draws from vials of Bevacizumab (Avastin, Genentech) when preparing intravitreal injections in a staged clinical setting.
Methods
Prospective, case control series with three arms of 92 experiments with bacterial cultures obtained from needles and instruments used in the preparation of Bevacizumab intravitreal injections. Sterile NaCl was used as control. Arm 1 included bacterial cultures of instruments used in routine intravitreal injections (speculum, caliper, forceps, 18 and 30 gauge needles) along with peri-operative medications. Arm 2 included bacterial cultures of needles when used to separately draw Bevacizumab or NaCl employing multiple punctures of each vial with minimal time delay in between draws. Arm 2 also included sources of possible contaminants when deviating from standard local protocol which includes the use of sterile gloves, alcohol swabs to the vial top, and face mask. Arm 3 examined bacterial cultures of needles when multiple punctures were performed at hourly intervals and up to 5 hours from the initial draw, with the Bevacizumab vial being refrigerated in between each draw. All samples were cultured in Thioglycolate broth, where positive contamination was declared when turbidity of the growth medium was observed. The turbid samples were further cultured for identification on standard plates.
Results
Arm 1 showed no growth from sterile instrumentation or peri-operative topical medications (10 cultures, p=1.00). Arm 2 displayed no growth under standard local protocol. However, Arm 2 had growth of alpha-hemolytic streptococci and diphtheroids when the Bevacizumab vial was subjected to sternutation without applying alcohol swab to the vial top (64 cultures, p=0.216). Arm 3 had no growth when time delay draws were performed (18 cultures, p=1.00).
Conclusions
Our study shows relative safety when drawing multiple doses of Bevacizumab for use in intravitreal injection via 18 gauge puncture from one single use vial, either with minimal time delay or with refrigeration of the vial in between serial draws when a standardized technique is used in a staged clinical setting. We observed that exposure to oropharyngeal fomites with deviation from protocol may elevate the risk of bacterial contamination of needles.
Keywords: 513 endophthalmitis •
561 injection •
688 retina