Topical ocular antibiotics induce bacterial resistance at extraocular sites

Br J Ophthalmol. 2005 Sep;89(9):1097-9. doi: 10.1136/bjo.2005.068981.


Aim: 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.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Administration, Oral
  • Administration, Topical
  • Anti-Bacterial Agents / administration & dosage*
  • Anti-Bacterial Agents / therapeutic use
  • Azithromycin / administration & dosage*
  • Azithromycin / therapeutic use
  • Child
  • Child, Preschool
  • Drug Administration Schedule
  • Drug Resistance, Bacterial
  • Female
  • Humans
  • Infant
  • Male
  • Nasopharyngeal Diseases / microbiology
  • Nasopharynx / microbiology*
  • Nepal
  • Ointments
  • Streptococcus pneumoniae / drug effects
  • Tetracycline / administration & dosage*
  • Tetracycline / therapeutic use
  • Tetracycline Resistance
  • Time Factors
  • Trachoma / drug therapy*


  • Anti-Bacterial Agents
  • Ointments
  • Azithromycin
  • Tetracycline