title: A prospective study of the impact of community-based azithromycin treatment of trachoma on carriage and resistance of Streptococcus pneumoniae.
abstract: In February 1995, single-dose azithromycin was given to children with trachoma and their household contacts who were children. For children with trachoma, rates of carriage of pneumococci immediately before treatment with azithromycin and 2-3 weeks, 2 months, and 6 months after treatment were 68% (54 of 79), 29% (11 of 38), 78% (29 of 37), and 87% (34 of 39), respectively. The proportion of carriage-positive children with azithromycin-resistant Streptococcus pneumoniae strains was 1 of 54 (1.9%) before treatment and then 6 of 11 (54.5%), 10 of 29 (34.5%), and 2 of 34 (5.9%) at follow-up visits. The profile of pneumococcal serotypes changed after azithromycin treatment. Azithromycin-resistant strains (serotypes 10F, 23A, and 45) were isolated from 1 (1.3%) of 79 pretreatment swab specimens, from 16 (21.3%) of 75 swab specimens collected up to 2 months after treatment, and from 2 (6%) of 32 obtained 6 months after treatment. Mathematical modeling showed a more rapid appearance of azithromycin-resistant pneumococcal strains in previously colonized children than in previously noncolonized children. Thus, it appears that the selective effect of azithromycin allowed the growth and transmission of preexisting azithromycin-resistant strains. More research is needed to clarify the clinical relevance and implications of azithromycin use.
authors.affiliation: Menzies School of Health Research, Darwin, Northern Territory, Australia.
authors.forename: A J
authors.initials: AJ
authors.lastname: Leach
authors.forename: T M
authors.initials: TM
authors.lastname: Shelby-James
authors.forename: M
authors.initials: M
authors.lastname: Mayo
authors.forename: M
authors.initials: M
authors.lastname: Gratten
authors.forename: A C
authors.initials: AC
authors.lastname: Laming
authors.forename: B J
authors.initials: BJ
authors.lastname: Currie
authors.forename: J D
authors.initials: JD
authors.lastname: Mathews
mesh_terms: D000293:Adolescent; D000900:Anti-Bacterial Agents / Q000494:pharmacology / Q000627:therapeutic use*; D017963:Azithromycin / Q000494:pharmacology / Q000627:therapeutic use*; D002353:Carrier State / Q000382:microbiology*; D002648:Child; D002675:Child, Preschool; D004352:Drug Resistance, Microbial; D004917:Erythromycin / Q000494:pharmacology; D006801:Humans; D008137:Longitudinal Studies; D009305:Nasopharynx / Q000382:microbiology; D015876:Northern Territory; D011008:Pneumococcal Infections / Q000382:microbiology*; D011446:Prospective Studies; D013296:Streptococcus pneumoniae / Q000187:drug effects / Q000302:isolation & purification*; D014141:Trachoma / Q000188:drug therapy*
chemical_list: D000900:Anti-Bacterial Agents; D004917:Erythromycin; D017963:Azithromycin