Needle contamination in the setting of intravitreal injections.

Background/purpose: To evaluate the risk of intravitreal needle contamination through speaking versus breathing in an office setting.

Methods: This was a prospective sampling assay. Participants held a sterile 30-gauge half-inch needle 25 cm from their mouth for 30 seconds under 2 conditions: (1) while speaking and (2) while breathing silently. Needles were then cultured and assayed after 6 days of incubation. Absolute colony-forming units were compared between conditions and against control sterile needles and oral swab cultures.

Results: Ten physicians were sampled with 15 samples per physician. Participants grew an average of 0.21 colonies (median = 1 CFU) from their talking samples and 0.07 colonies (median = 1 CFU) from their silent breathing samples. Oral swab plates grew an average of 373.4 colonies. None of the control needle plates grew colony-forming units. A nominal regression analysis showed no significant difference between talking and silent samples (P = 0.457).

Conclusion: No significant difference in needle contamination was found between talking and breathing. Compared with oral swab plates, a significant difference exists between the amount of flora colonizing the oropharynx and that which was found on the needle cultures (P < 0.0001). These findings suggest that speaking versus remaining silent makes no difference in regard to needle contamination with oral flora during intravitreal injection.