Conjunctival flora and their antibiotic susceptibility in patients undergoing penetrating intraocular surgeries / 中华实验眼科杂志

ABSTRACT

Objective To determine the spectrum of conjunctival flora and the antibiotic susceptibility profiles of patients scheduled for penetrating intraocular surgeries.Methods A prospective case control study was performed.A total of 192 patients (192 eyes) scheduled for penetrating intraocular surgeries at the Fourth People's Hospital of Shenyang from February to August 2015 were enrolled.Samples from the conjunctival sac were collected before instillation of any ophthalmic solutions for both aerobic and anaerobic culture.The positive rate and bacterial spectrum were observed.Bacterial isolates were tested for antibiotic susceptibility to 7 commonly used ophthalmic antibiotics using automated drug resistance analyzing system.The research was approved by the Ethics Committee of the Fourth People's Hospital of Shenyang.Results Totally 91 strains were collected from 81 conjunctival samples during aerobic culture,the positive rate was 42.19％.Staphylococcus epidermidis was the most common microorganism (64.84％),followed by Staphylococcus lentus (7.69％) and Staphylococcus aureus (3.30％).Coagulatase negtive Staphylococcus (CNS) accounted for 80.22％ of the positively cultured aerobes.For anaerobic culture,a total of 28 strains were isolated from 28 conjunctival samples,the positive rate was 14.58％ Propionibacterium acnes was the predominant species (71.43％),followed by Finegoldia magna (10.71％).Majority of the CNS were sensitive to gentamycin and vancomycin,with resistance rates lower than 10％,but their resistance rate to erythromycin and ceftazidime was 87.67％ and 63.01％,respectively.Resistance rate of these CNS to levofloxacin,ciprofloxacin,and moxifloxacin was 42.47％,39.73％ and 17.81％,respectively.Multidrug resistance to at least 3 antibiotic classes was present in 38.36％ of the CNS.Conclusions Bacteria in the conjunctiva sac of preoperative patients are resistant to various ophthalmic antibiotics.To follow-up the bacterial distribution and antibiotic resistance is great meaningful in the prophylactic and treatment in ocular surgery-related infections.