Haemophilus influenzae in COPD: Effect of fluoroquinolones and macrolides on eradication and resistance.
Antimicrob Agents Chemother. 2016 May 2;
Authors: Pettigrew MM, Tsuji BT, Gent JF, Kong Y, Holden PN, Sethi S, Murphy TF
Little is known about the effect of antibiotics on eradication of carriage and development of resistance in Haemophilus influenzae in individuals with chronic obstructive pulmonary disease (COPD). Our goals were to assess antibiotic susceptibilities, prevalence of resistance genes, and development of resistance in H. influenzae and to evaluate the effect of macrolide and fluoroquinolone administration on H. influenzae eradication. Data were from a 15-year longitudinal study of COPD. Genome sequence data were used to determine genotype and identify resistance genes. Minimum inhibitory concentrations to antibiotics were determined by reference broth microdilution. Generalized linear mixed models were used to evaluate associations between antibiotic use and H. influenzae eradication. We examined 267 H. influenzae isolates from 77 individuals. All newly acquired H. influenzae isolates were susceptible to azithromycin. Five of 27 (19%) strains developed four-fold increases in azithromycin minimum inhibitory concentrations (MIC) and reached or exceeded the susceptibility breakpoint (≤4 μg/mL) during exposure. H. influenzae were uniformly susceptible for ciprofloxacin, levofloxacin, and moxifloxacin (MIC90=0.015, 0.015, 0.06, respectively); there were no mutations in quinolone resistance-determining regions. Fluoroquinolone administration was associated with increased H. influenzae eradication compared to macrolides (odds ratio [OR] 16.67, 95% confidence interval [CI], 2.67-104.09). There was no difference in H. influenzae eradication when comparing macrolide administration to no antibiotic (OR 1.89, [95% CI, 0.43-8.30]). Fluoroquinolones are effective in eradicating H. influenzae in individuals with COPD. Macrolides are ineffective in eradicating H. influenzae and their use in COPD patients may lead to decreased macrolide susceptibility and resistance.
PMID: 27139476 [PubMed - as supplied by publisher]