Trends in Microbiological and Antibiotic Sensitivity Patterns in Infectious Keratitis: 10-Year Experience in Mexico City

Cornea. 2015 Jul;34(7):778-85. doi: 10.1097/ICO.0000000000000428.


Purpose: To report the distribution and trends in microbiological and antibiotic sensitivity patterns of infectious keratitis in a 10-year period at a reference center in Mexico City.

Methods: In this retrospective observational case series, samples were obtained from corneas with a diagnosis of infectious keratitis from January 2002 to December 2011 at the Institute of Ophthalmology "Conde de Valenciana" in Mexico City. Results of cultures, stains, and specific sensitivity/resistance antibiograms for each microorganism were analyzed.

Results: A total of 1638 consecutive corneal scrapings were analyzed. Pathogen was recovered in 616 samples (38%), with bacterial keratitis accounting for 544 of the positive cultures (88%). A nonsignificant increasing trend in gram-negative isolates (P = 0.11) was observed. The most commonly isolated pathogen was Staphylococcus epidermidis, and the most common gram-negative isolated species was Pseudomonas aeruginosa. Methicillin-resistant Staphylococcus aureus (MRSA) was present in 45% of the S. aureus isolates; meanwhile, 53.7% coagulase-negative Staphylococcus isolates were methicillin resistant (MRCNS). Pseudomonas aeruginosa resistance to ceftazidime increased from 15% in the first period to 74% for the last 5 years of the study (P = 0.01). The overall sensitivity for vancomycin of MRSA was 87.5%, whereas 99.6% of the MRCNS were sensitive.

Conclusions: There was a nonsignificant increase in the recovered gram-positive and gram-negative microorganisms over time. We observed an increased resistance to methicillin in almost half of the MRSA and MRCNS isolates.

Publication types

  • Observational Study

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Anti-Bacterial Agents / therapeutic use*
  • Child
  • Child, Preschool
  • Corneal Ulcer / epidemiology
  • Corneal Ulcer / microbiology*
  • Drug Resistance, Bacterial
  • Eye Infections, Bacterial / epidemiology
  • Eye Infections, Bacterial / microbiology*
  • Female
  • Gram-Negative Bacteria / isolation & purification
  • Gram-Negative Bacterial Infections / epidemiology
  • Gram-Negative Bacterial Infections / microbiology*
  • Gram-Positive Bacteria / isolation & purification
  • Gram-Positive Bacterial Infections / epidemiology
  • Gram-Positive Bacterial Infections / microbiology*
  • Humans
  • Infant
  • Male
  • Mexico / epidemiology
  • Microbial Sensitivity Tests / trends
  • Middle Aged
  • Retrospective Studies


  • Anti-Bacterial Agents