Mass azithromycin distribution propagates antibiotic resistance
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Research has shown that mass distributing azithromycin to preschool children in sub-Saharan Africa can reduce child mortality — a benefit that has been shown to last for years.
However, experts have expressed concern that the benefits of mass drug administrations would be tempered by the emergence of antibiotic resistance. Now, researchers have demonstrated that mass distributing azithromycin to children may contribute to growing antibiotic resistance, although they said the data suggest a slowed rate of resistance after 2 years and no evidence of a public health problem, according to findings published in The New England Journal of Medicine.
“Trachoma programs have been doing annual mass azithromycin distributions for the past 20 years,” Thuy Doan, MD, PhD, director of the Ralph and Sophie Heintz Laboratory at the University of California, San Francisco’s Francis I. Proctor Foundation, explained to Healio.
Doan and colleagues used rectal swabs collected at baseline, 36 months, and 48 month to assess the gut resistome of children aged 1 to 59 months in Niger after they received azithromycin every 6 months for 4 years. According to the study, participants received either mass-distributed azithromycin or placebo.
Doan said they monitored communities in their third and fourth years of distributions and “as expected, found more macrolide resistance in the azithromycin-treated communities.”
“Good news? Not much more resistance [than] we’d seen at 2 years, so resistance may not go up and up with more years of distribution. And although not compared directly, we’re seeing less resistance than has been seen in trachoma programs,” she said. “Bad news? We’re seeing the suggestion of resistance in other classes of antibiotics.”
The researchers collected a total of 3,232 samples. Of the samples obtained at the 48-month monitoring visit, they analyzed 546 samples from 15 villages that received placebo and 504 from 14 villages that received azithromycin. The study demonstrated that “determinants of macrolide resistance” were higher in the azithromycin group than in the placebo group 7.4 times as high (95% CI, 4-16.7) at 36 months and 7.5 times as high (95% CI, 3.8-23.1) at 48 months.
Continued mass azithromycin distributions also selected for determinants of nonmacrolide resistance, including resistance to beta-lactam antibiotics, which are prescribed frequently in this region of Africa, the researchers reported.
“One last point nearly a billion doses of azithromycin have been distributed for trachoma control,” Doan said. “The program is winding down now due to its own success, but we have no substantial evidence that increased resistance created a public health problem and, when assessed, macrolide resistance has decreased after programs have stopped.”
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