The impact of short-term topical gatifloxacin and moxifloxacin on bacterial injection after hypodermic needle passage through human conjunctiva.

PURPOSE: To determine the bacterial contamination rate of a 27-gauge needle bore during conjunctival penetration in donor eye bank eyes and the effect of short-term use of topical 0.3% gatifloxacin and 0.5% moxifloxacin.

METHODS

One hundred consecutive human donors had 10 conjunctival penetrations per 10 syringes per eye before antibiotic placement; this was repeated 15 min after antibiotic use. Samples were cultured by expressing 0.3 mL of saline through the needle. Positive cultures were speciated.

RESULTS

There were 1,033 positive cultures (25.8% of all cultures); 568 (28.4%) pre-antibiotics, 249 (24.9%) after gatifloxacin (P=0.04, compared to the pre-antibiotic rate), and 216 (21.6%) after moxifloxacin (P<0.001). The most common organism was Staphylococcus epidermidis [334 positive cultures (8.4%)]. No antibiotic effect was seen on this or other organisms except S. aureus [4.6% pre-antibiotic, 2.8% after gatifloxacin (P=0.02), and 1.8% after moxifloxacin (P<0.001)] and other Staphylococcus species [5.3% pre-antibiotic, 3.6% after gatifloxacin (P=0.04), and 3.2% after moxifloxacin (P=0.01)].

CONCLUSIONS

Transconjunctival penetration often results in needle bore contamination; bacteria are included in an injected solution. Fifteen minutes of exposure to 2 topical antibiotics had a minimal effect on bacterial contamination and no significant effect on many common pathogens.