 repeatedly exposed to fluoroquinolone or azithromycin antibiotics quickly develops resistance in patients undergoing serial unilateral intravitreal (IVT) injections for choroidal neovascularization, states a paper published in 

A team led by Dr Stephen J. Kim, Vanderbilt Eye Institute, Nashville, Tennessee, USA, performed a prospective, controlled, longitudinal study with 1-year follow-up on 48 eyes of 24 patients. Each patient was administered 4 consecutive monthly serial unilateral intravitreal (IVT) injections for choroidal neovascularization.

The purpose of the study was to analyze the occurrence of multidrug-resistant 

 after the repetition of conjunctival exposure topical macrolide or fluoroquinolone antibiotics. The main outcome measure was the antibiotic susceptibility patterns and multidrug resistance of 

After 4 consecutive treatments, 58 isolates of 

 were separated from control and treated eyes. In 69% of 

 isolated from control eyes there was resistance to 3 or more antibiotics, compared to 90% from treated eyes.

From control and treated eyes there was a total of 46 and 38 isolates of 

, respectively. In 48% of control eyes and 71% of treated eyes there was a resistance to 5 or more antibiotics. 

 developed resistance to several fluoroquinolone-treated eyes compared to control eyes. The organisms also developed resistance to trimethoprim/sulfamethoxazole, gentamicin, and clindamycin.

A large number of azithromycin-treated eyes developed S. epidermidis resistant to macrolides, compared with control eyes. The azithromycin-treated eyes also developed a higher resistance to trimethoprim/sulfamethoxazole and doxycycline.

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Conjunctival S.epidermidis. repeatedly exposed to fluoroquinolone or azithromycin antibiotics quickly develops resistance in patients undergoing serial unilateral intravitreal (IVT) injections for choroidal neovascularization