Bacterial contamination of ocular surface and needles in patients undergoing intravitreal injections.
OBJECTIVE
To evaluate potential sources of bacterial contamination during intravitreal (IVT) injection procedures.


METHODS
Patients scheduled for IVT injection were asked to enroll in the study at the California Vitreoretinal Center (Menlo Park, CA) and the Vantage Eye Center (Salinas, CA) between October 2004 and April 2005. A total of 104 patients participated in the study, with a total of 118 IVT injection procedures performed on 107 eyes. Standard microbiological techniques were used to culture, identify, and quantify bacterial contamination of injection needles and the bulbar conjunctiva at the injection site in patients undergoing IVT injections. The main outcomes measured were type and quantity of bacterial isolates.


RESULTS
Two (2%) of 114 needles collected were contaminated with bacteria. The prevalence of bacterial contamination of the injection site on the bulbar conjunctiva was 43% before prophylaxis on the day of the injection with topical antibiotics and povidone-iodine, with a statistically significant reduction to 13% after prophylaxis (P < 0.0001). Coagulase-negative Staphylococcus, the most common bacterium isolated from the ocular surface, was isolated from both culture-positive needles.


CONCLUSIONS
IVT injection needles became contaminated with bacteria during the injection procedure. Although the contamination rate was low, this supports a mechanism of postinjection endophthalmitis in which there is direct inoculation of ocular surface flora into the vitreous cavity by the injection needle.
Department of Ophthalmology, Stanford University School of Medicine, Stanford, CA, USA.
John J
JJ
de Caro
Christopher N
CN
Ta
Hoai-Ky V
HK
Ho
Lorella
L
Cabael
Nan
N
Hu
Steven R
SR
Sanislo
Mark S
MS
Blumenkranz
Darius M
DM
Moshfeghi
Robert
R
Jack
Herminia Miño
HM
de Kaspar
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000008:administration & dosage; D001419:Bacteria / Q000302:isolation & purification*; D001431:Bacteriological Techniques; D003228:Conjunctiva / Q000382:microbiology*; D009877:Endophthalmitis / Q000382:microbiology / Q000517:prevention & control; D004866:Equipment Contamination; D005260:Female; D006801:Humans; D007267:Injections; D008297:Male; D008875:Middle Aged; D009339:Needles / Q000382:microbiology*; D011206:Povidone-Iodine / Q000008:administration & dosage; D014822:Vitreous Body
D000900:Anti-Bacterial Agents; D011206:Povidone-Iodine