title: Trends in antibiotic resistance in bacterial keratitis isolates from South India.
abstract: To report trends in antibiotic resistance in cases of bacterial keratitis from a large eye hospital in South India.
  
  
  
  In this retrospective cross-sectional study, the microbiology laboratory records of patients with infectious keratitis diagnosed at an eye hospital in South India from 2002 to 2013 were reviewed to determine the proportion with antibiotic non-susceptibility.
  
  
  
  3685 bacterial isolates had susceptibility testing performed over the 12-year period. The two most common organisms with resistance were Streptococcus pneumoniae (n=1204) and Pseudomonas aeruginosa (n=894). Antibiotic non-susceptibility was generally uncommon for these two organisms and no significant trends were detected over the course of the study. In contrast, Staphylococcus aureus (N=211) isolates demonstrated a significant increase in fluoroquinolone non-susceptibility over the 12-year study period. This coincided with a significant increase in methicillin-resistant S. aureus (MRSA) during the study period, though the increase in fluoroquinolone resistance was likewise seen in methicillin-sensitive S. aureus (MSSA). For example, ofloxacin resistance in MSSA increased from 11.1% in 2002 to 66.7% in 2013 (p=0.002). No trends were apparent for the aminoglycosides, cefazolin or vancomycin, for which in vitro non-susceptibility generally appeared to be low.
  
  
  
  Resistance to antibiotics was generally stable for infectious keratitis isolates from a large eye hospital in South India, except for S. aureus, which experienced a significant increase in fluoroquinolone resistance from 2002 to 2013. Fluoroquinolone antibiotics currently have poor in vitro activity against both MRSA and MSSA in South India and are therefore not the ideal therapy for Staphylococcal corneal ulcers.
authors.affiliation: Department of Ocular Microbiology, Aravind Eye Care System, Madurai, Tamil Nadu, India.
authors.forename: Prajna
authors.initials: P
authors.lastname: Lalitha
authors.affiliation: Department of Ocular Microbiology, Aravind Eye Care System, Madurai, Tamil Nadu, India.
authors.forename: Geetha
authors.initials: G
authors.lastname: Manoharan
authors.affiliation: Department of Ocular Microbiology, Aravind Eye Care System, Madurai, Tamil Nadu, India.
authors.forename: Rajaram
authors.initials: R
authors.lastname: Karpagam
authors.affiliation: Department of Cornea and External Diseases, Aravind Eye Care System, Madurai, Tamil Nadu, India.
authors.forename: Namperumalsamy V
authors.initials: NV
authors.lastname: Prajna
authors.affiliation: Department of Cornea and External Diseases, Aravind Eye Care System, Madurai, Tamil Nadu, India.
authors.forename: Muthiah
authors.initials: M
authors.lastname: Srinivasan
authors.affiliation: Department of Cornea and External Diseases, Aravind Eye Care System, Madurai, Tamil Nadu, India.
authors.forename: Jeena
authors.initials: J
authors.lastname: Mascarenhas
authors.affiliation: Department of Cornea and External Diseases, Aravind Eye Care System, Madurai, Tamil Nadu, India.
authors.forename: Manoranjan
authors.initials: M
authors.lastname: Das
authors.affiliation: Francis I. Proctor Foundation, University of California, San Francisco, California, USA.|Department of Ophthalmology, University of California, San Francisco, California, USA.|Department of Epidemiology & Biostatistics, University of California, San Francisco, California, USA.
authors.forename: Travis C
authors.initials: TC
authors.lastname: Porco
authors.affiliation: Francis I. Proctor Foundation, University of California, San Francisco, California, USA.|Department of Ophthalmology, University of California, San Francisco, California, USA.|Department of Epidemiology & Biostatistics, University of California, San Francisco, California, USA.
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Lietman
authors.affiliation: Francis I. Proctor Foundation, University of California, San Francisco, California, USA.
authors.forename: Vicky
authors.initials: V
authors.lastname: Cevallos
authors.affiliation: Francis I. Proctor Foundation, University of California, San Francisco, California, USA.|Department of Ophthalmology, University of California, San Francisco, California, USA.
authors.forename: Jeremy D
authors.initials: JD
authors.lastname: Keenan
mesh_terms: D000328:Adult; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D003430:Cross-Sectional Studies; D024881:Drug Resistance, Bacterial; D015818:Eye Infections, Bacterial / Q000382:microbiology*; D005260:Female; D006090:Gram-Negative Bacteria / Q000187:drug effects*; D006094:Gram-Positive Bacteria / Q000187:drug effects*; D006801:Humans; D007194:India; D007634:Keratitis / Q000382:microbiology*; D008297:Male; D012189:Retrospective Studies
chemical_list: D000900:Anti-Bacterial Agents
keywords: Cornea; Infection