Spectrum and susceptibility of preoperative conjunctival bacteria

• Published in: Archivos de la Sociedad Española de Oftalmología (English ed.) 2013-12, Vol.88 (12), p.458-465
• Main Authors: Fernández-Rubio, M.E, Cuesta-Rodríguez, T, Urcelay-Segura, J.L, Cortés-Valdés, C
• Format: Article
• Language: English
• Subjects: Antibiotic susceptibility; Bacteria colonizers; Bacterias colonizadoras; Bacterias conjuntivales; Colonizadores conjuntivales; Conjunctival bacteria; Conjunctival colonizers; Endoftalmitis postoperatoria; Ophthalmology; Postoperative endophthalmitis; Profilaxis quirúrgica; Surgical prophylaxis; Susceptibilidad antibiótica
• ISSN: 2173-5794; 2173-5794
• DOI: 10.1016/j.oftale.2014.01.007

Abstract Purpose To describe the conjunctival bacterial spectrum of our patients undergoing intraocular surgery and their antibiotic sensitivity during the study period. Methods A retrospective study of preoperative conjunctival culture of patients consecutively scheduled for intraocular surgery from 21 February 2011 to 1 April 2013. Specimens were directly seeded onto blood-agar and MacConkey-agar (aerobiosis incubation, 2 days), and on chocolate-agar (6% CO2 incubation, 7 days). The identified bacteria were divided into 3 groups according to their origin; the bacteria susceptibility tests were performed on those more pathogenic and on some of the less pathogenic when more than 5 colonies were isolated. The sensitivity of the exigent growing bacteria was obtained with disk diffusion technique, and for of the non-exigent bacteria by determining their minimum inhibitory concentration. The Epidat 3.1 program was used for statistical calculations. Results A total of 13,203 bacteria were identified in 6051 cultures, with 88.7% being typical colonizers of conjunctiva (group 1), 8.8% typical of airways (group 2), and the remaining 2.5% of undetermined origin (group 3). 530 cultures (8.8%) were sterile. The sensitivity of group 1 was: 99% vancomycin, 95% rifampicin, 87% chloramphenicol, 76% tetracycline. Levels of co-trimoxazole, aminoglycosides, quinolones, β-lactams and macrolides decreased since 2007. The group 2 was very sensitive to chloramphenicol, cefuroxime, rifampicin, ciprofloxacin and amoxicillin/clavulanate. In group 3, to levofloxacin 93%, ciprofloxacin 89%, tobramycin 76%, but ceftazidime 53% and cefuroxime 29% decreased. Conclusions None of the tested antibiotics could eradicate all possible conjunctival bacteria. Bacteria living permanently on the conjunctiva (group 1) have achieved higher resistance than the eventual colonizers.