title: [Spectrum and susceptibility of preoperative conjunctival bacteria].
abstract: OBJECTIVE
  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 6,051 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.
authors.affiliation: Departamento de Oftalmología, Instituto Oftálmico, Laboratorio de Análisis Clínicos, Hospital General Universitario Gregorio Marañón, Madrid, España. Electronic address: mfernandezr.hgugm@salud.madrid.org.
authors.forename: M E
authors.initials: ME
authors.lastname: Fernández-Rubio
authors.forename: T
authors.initials: T
authors.lastname: Cuesta-Rodríguez
authors.forename: J L
authors.initials: JL
authors.lastname: Urcelay-Segura
authors.forename: C
authors.initials: C
authors.lastname: Cortés-Valdés
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D019072:Antibiotic Prophylaxis; D001419:Bacteria / Q000187:drug effects / Q000302:isolation & purification*; D002444:Cefuroxime / Q000494:pharmacology / Q000627:therapeutic use; D003228:Conjunctiva / Q000382:microbiology*; D003430:Cross-Sectional Studies; D052978:Disk Diffusion Antimicrobial Tests; D024881:Drug Resistance, Bacterial; D024901:Drug Resistance, Multiple, Bacterial; D006801:Humans; D008826:Microbial Sensitivity Tests; D013508:Ophthalmologic Surgical Procedures; D011300:Preoperative Care; D012137:Respiratory System / Q000382:microbiology; D012189:Retrospective Studies; D012867:Skin / Q000382:microbiology; D013045:Species Specificity; D013530:Surgical Wound Infection / Q000517:prevention & control
chemical_list: D000900:Anti-Bacterial Agents; D002444:Cefuroxime
keywords: Antibiotic susceptibility; Bacteria colonizers; Bacterias colonizadoras; Bacterias conjuntivales; Colonizadores conjuntivales; Conjunctival bacteria; Conjunctival colonizers; Endoftalmitis postoperatoria; Postoperative endophthalmitis; Profilaxis quirúrgica; Surgical prophylaxis; Susceptibilidad antibiótica