title: Mass administration of azithromycin and Streptococcus pneumoniae carriage: cross-sectional surveys in the Gambia.
abstract: OBJECTIVE
  To evaluate the effect of repeated mass drug administration (MDA) of azithromycin in the Gambia on the nasopharyngeal carriage of Streptococcus pneumoniae and on the emergence of antibiotic-resistant strains.
  
  
  METHODS
  This study involved villages that participated in a cluster randomized trial comparing the effect of one versus three azithromycin MDA rounds on the prevalence of trachoma. Only villages in which most children received 7-valent pneumococcal conjugate vaccine were included. Three cross-sectional surveys were performed in two villages that received three annual MDA rounds: the first immediately before the third MDA round and the second and third, 1 and 6 months, respectively, after the third MDA round. The third survey also covered six villages that had received one MDA round 30 months previously. Pneumococcal carriage was assessed using nasopharyngeal swabs and azithromycin resistance was detected using the Etest.
  
  
  RESULTS
  The prevalence of pneumococcal carriage decreased from 43.4% to 19.2% between the first and second surveys (P < 0.001) but rebounded by the third survey (45.8%; P = 0.591). Being a carrier at the first survey was a risk factor for being a carrier at the second (odds ratio: 3.71; P <  0.001). At the third survey, the prevalence of carriage was similar after one and three MDA rounds (50.3% versus 45.8%, respectively; P = 0.170), as was the prevalence of azithromycin resistance (0.3% versus 0.9%, respectively; P = 0.340).
  
  
  CONCLUSIONS
  Three azithromycin MDA rounds did not increase the prevalence of nasopharyngeal carriage of azithromycin-resistant S. pneumoniae strains compared with one round.
authors.affiliation: Department of Clinical Research, London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, England .
authors.forename: Sarah E
authors.initials: SE
authors.lastname: Burr
authors.affiliation: Faculty of Life Sciences, University of Manchester, Manchester, England .
authors.forename: Sally
authors.initials: S
authors.lastname: Milne
authors.affiliation: Medical Research Council Unit, Fajara, Banjul, Gambia .
authors.forename: James
authors.initials: J
authors.lastname: Jafali
authors.affiliation: Medical Research Council Unit, Fajara, Banjul, Gambia .
authors.forename: Ebrima
authors.initials: E
authors.lastname: Bojang
authors.affiliation: Department of Clinical Research, London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, England .
authors.forename: Megha
authors.initials: M
authors.lastname: Rajasekhar
authors.affiliation: Department of Clinical Research, London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, England .
authors.forename: John
authors.initials: J
authors.lastname: Hart
authors.affiliation: Public Health England, Colindale, London, England .
authors.forename: Emma M
authors.initials: EM
authors.lastname: Harding-Esch
authors.affiliation: Department of Clinical Research, London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, England .
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Holland
authors.affiliation: Department of Clinical Research, London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, England .
authors.forename: David C W
authors.initials: DC
authors.lastname: Mabey
authors.affiliation: National Eye Health Programme, Ministry of Health and Social Welfare, Kanifing, Gambia .
authors.forename: Ansumana
authors.initials: A
authors.lastname: Sillah
authors.affiliation: Department of Clinical Research, London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, England .
authors.forename: Robin L
authors.initials: RL
authors.lastname: Bailey
authors.affiliation: Medical Research Council Unit, Fajara, Banjul, Gambia .
authors.forename: Anna
authors.initials: A
authors.lastname: Roca
mesh_terms: D000900:Anti-Bacterial Agents / Q000008:administration & dosage*; D017963:Azithromycin / Q000008:administration & dosage*; D002353:Carrier State; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D024881:Drug Resistance, Bacterial; D005260:Female; D005714:Gambia / Q000453:epidemiology; D006801:Humans; D017589:Immunization Programs; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D009305:Nasopharynx / Q000382:microbiology*; D022242:Pneumococcal Vaccines / Q000008:administration & dosage; D015995:Prevalence; D012307:Risk Factors; D012424:Rural Population; D013296:Streptococcus pneumoniae / Q000187:drug effects*; D014141:Trachoma / Q000188:drug therapy* / Q000453:epidemiology
chemical_list: D000900:Anti-Bacterial Agents; D022242:Pneumococcal Vaccines; D017963:Azithromycin
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