title: Topical ocular antibiotics induce bacterial resistance at extraocular sites.
abstract: OBJECTIVE
  To compare the prevalence of antibiotic resistance found in nasopharyngeal Streptococcus pneumoniae between villages treated with topical tetracycline or systemic azithromycin as part of a trachoma control programme.
  
  
  METHODS
  All children aged 1-10 years were offered either single dose oral azithromycin treatment (20 mg/kg) or a course of topical 1% tetracycline ointment, depending on the area. Treatment was given annually for 3 years. Six months after the third annual treatment in each village, children were surveyed for nasopharyngeal carriage of S pneumoniae and resistance was determined using broth dilution MIC technique. Children in two additional villages, which had not yet been treated, were also surveyed.
  
  
  RESULTS
  Nasopharyngeal carriage of S pneumoniae was similar in the tetracycline treated, azithromycin treated, and untreated areas (p=0.57). However, resistance to tetracycline and azithromycin was distributed differently between the three areas (p=0.004). The village treated with topical tetracycline had a higher prevalence of tetracycline resistance than the other villages (p=0.010), while the oral azithromycin treated village had a higher prevalence of macrolide resistance than the other villages (p=0.014).
  
  
  CONCLUSIONS
  Annual mass treatment with oral azithromycin may alter the prevalence of drug resistant S pneumoniae in a community. Surprisingly, topical tetracycline may also increase nasopharyngeal pneumococcal resistance. Topical antibiotics may have an effect on extraocular bacterial resistance.
authors.affiliation: Department of Ophthalmology, F I Proctor Foundation, 95 Kirkham Street, Room 307, University of California San Francisco, San Francisco, CA 94143-0944, USA.
authors.forename: B D
authors.initials: BD
authors.lastname: Gaynor
authors.forename: J D
authors.initials: JD
authors.lastname: Chidambaram
authors.forename: V
authors.initials: V
authors.lastname: Cevallos
authors.forename: Y
authors.initials: Y
authors.lastname: Miao
authors.forename: K
authors.initials: K
authors.lastname: Miller
authors.forename: H C
authors.initials: HC
authors.lastname: Jha
authors.forename: R C
authors.initials: RC
authors.lastname: Bhatta
authors.forename: J S P
authors.initials: JS
authors.lastname: Chaudhary
authors.forename: S
authors.initials: S
authors.lastname: Osaki Holm
authors.forename: J P
authors.initials: JP
authors.lastname: Whitcher
authors.forename: K A
authors.initials: KA
authors.lastname: Holbrook
authors.forename: A M
authors.initials: AM
authors.lastname: Fry
authors.forename: T M
authors.initials: TM
authors.lastname: Lietman
mesh_terms: D000284:Administration, Oral; D000287:Administration, Topical; D000900:Anti-Bacterial Agents / Q000008:administration & dosage* / Q000627:therapeutic use; D017963:Azithromycin / Q000008:administration & dosage* / Q000627:therapeutic use; D002648:Child; D002675:Child, Preschool; D004334:Drug Administration Schedule; D024881:Drug Resistance, Bacterial; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D009302:Nasopharyngeal Diseases / Q000382:microbiology; D009305:Nasopharynx / Q000382:microbiology*; D009390:Nepal; D009824:Ointments; D013296:Streptococcus pneumoniae / Q000187:drug effects; D013752:Tetracycline / Q000008:administration & dosage* / Q000627:therapeutic use; D013753:Tetracycline Resistance; D013997:Time Factors; D014141:Trachoma / Q000188:drug therapy*
chemical_list: D000900:Anti-Bacterial Agents; D009824:Ointments; D017963:Azithromycin; D013752:Tetracycline