Data from: The impact of long-term azithromycin on antibiotic resistance in HIV-associated chronic lung disease

Background: Selection for resistance to azithromycin (AZM) and other antibiotics such as tetracyclines and lincosamides remains a concern with long-term AZM use for treatment of chronic lung diseases (CLD). We investigated the impact of 48 weeks of AZM on the carriage and antibiotic resistance of common respiratory bacteria among children with HIV-associated CLD.

Methods: Nasopharyngeal (NP) swabs and sputa were collected at baseline, 48 and 72 weeks from participants with HIV-associated CLD randomised to receive weekly AZM or placebo for 48 weeks and followed post-intervention until 72 weeks. The primary outcomes were prevalence and antibiotic resistance of Streptococcus pneumoniae (SP), Staphylococcus aureus (SA), Haemophilus influenzae (HI), and Moraxella catarrhalis (MC) at these timepoints. Mixed-effects logistic regression and Fisher's exact test were used to compare carriage and resistance respectively.

Results: Of 347 (174 AZM, 173 placebo) participants (median age 15 years [IQR =13–18], females 49%),NP carriage was significantly lower in the AZM (n=159) compared to placebo (n=153) arm for SP (18% vs 41%, p<0.001), HI (7% vs 16%, p=0.01), and MC (4% vs 11%, p=0.02); SP resistance to AZM (62% [18/29] vs 13%[8/63], p<0.0001) or tetracycline (60%[18/29] vs 21%[13/63], p<0.0001) were higher in the AZM arm. Carriage of SA resistant to AZM (91% [31/34] vs 3% [1/31], p<0.0001), tetracycline (35% [12/34] vs 13% [4/31], p= 0.05) and clindamycin (79% [27/34] vs 3% [1/31], p<0.0001) was also significantly higher in the AZM arm and persisted at 72 weeks. Similar findings were observed for sputa.

Conclusions: The persistence of antibiotic resistance and its clinical relevance for future infectious episodes requiring treatment needs further investigation.