E Fernández Rubio1, T Cuesta Rodríguez, C Cortés Valdés. 1. Hospital General Universitario Gregorio Marañón, Departamento de Oftalmología, Laboratorio de Análisis Clínicos del Instituto Oftálmico, Madrid, Spain. mfernandezr.hgugm@salud.madrid.org
Abstract
OBJECTIVE: To ascertain the effectiveness of various antibiotic eye-drops in eradicating the preoperative conjunctival bacteria of patients undergoing cataract surgery and to differentiate the failure of these treatments due to the lack of "in vitro" sensibility from other possible causes. METHODS: Retrospective study of the preoperative conjunctival flora of 4876 consecutive patients; "in vitro" sensibility was analysed by grouping bacteria into eight categories; the susceptibility percentages of the total conjunctival flora to five antibacterial agents were compared. The effectiveness of the eye-drop treatment with a single sensitive tested antibiotic (Aureomicin, Chloramphenicol, Gentamicin, Norfloxacin or Rifamicin) was evaluated in patients with pathogen bacteria. RESULTS: The "in vitro" sensibilities of Chloramphenicol (84.4%) and Rifampicin (83.9%) were similar (p < 0.01) and statistically higher than those of the other antibiotics. Nevertheless, the Chloramphenicol pathogen bacterium treatment failed in 21.2% of cases, in spite of being "in vitro" sensitive. Gentamicin presented the best effectiveness for eradicating Staphylococcus aureus and Gram (-) rods. Aureomicin had the best effectiveness against Streptococcus and Gram (-) diplococci. Rifamicin was the most effective for eradicating the whole predominant Gram (+) flora. The effectiveness of all five antibiotics decreased when there was more than one pathogen. CONCLUSIONS: None of the five antibiotic monotherapies maintains the patients' conjunctive free of pathogen bacteria 48 hours after finishing the treatment; however, there are bacterial patrons whose treatment could be optimised. The existence of polymicrobial flora decreases the effectiveness of the treatment.
OBJECTIVE: To ascertain the effectiveness of various antibiotic eye-drops in eradicating the preoperative conjunctival bacteria of patients undergoing cataract surgery and to differentiate the failure of these treatments due to the lack of "in vitro" sensibility from other possible causes. METHODS: Retrospective study of the preoperative conjunctival flora of 4876 consecutive patients; "in vitro" sensibility was analysed by grouping bacteria into eight categories; the susceptibility percentages of the total conjunctival flora to five antibacterial agents were compared. The effectiveness of the eye-drop treatment with a single sensitive tested antibiotic (Aureomicin, Chloramphenicol, Gentamicin, Norfloxacin or Rifamicin) was evaluated in patients with pathogen bacteria. RESULTS: The "in vitro" sensibilities of Chloramphenicol (84.4%) and Rifampicin (83.9%) were similar (p < 0.01) and statistically higher than those of the other antibiotics. Nevertheless, the Chloramphenicol pathogen bacterium treatment failed in 21.2% of cases, in spite of being "in vitro" sensitive. Gentamicin presented the best effectiveness for eradicating Staphylococcus aureus and Gram (-) rods. Aureomicin had the best effectiveness against Streptococcus and Gram (-) diplococci. Rifamicin was the most effective for eradicating the whole predominant Gram (+) flora. The effectiveness of all five antibiotics decreased when there was more than one pathogen. CONCLUSIONS: None of the five antibiotic monotherapies maintains the patients' conjunctive free of pathogen bacteria 48 hours after finishing the treatment; however, there are bacterial patrons whose treatment could be optimised. The existence of polymicrobial flora decreases the effectiveness of the treatment.