Study indicates yaws elimination strategy needs modification
A longitudinal study in Papua New Guinea has found that mass administration of antibiotics followed by targeted treatment did not eliminate yaws, researchers reported yesterday in The Lancet. The study also discovered the first signs of resistance in the tropical infection, which causes chronic disfiguring skin ulcers in children in at least 14 countries.
The World Health Organization's strategy to eliminate yaws, an infectious disease caused by Treponema pallidum subspecies pertenue (T p pertenue), is the mass administration of a single dose of azithromycin aiming for a population coverage of more than 90%, followed by active case detection surveys every 3 to 6 months. Previous studies had found that mass treatment with azithromycin was associated with a nearly 90% reduction of serologically-confirmed active yaws from 2.4% to 0.3%, but long-term efficacy has not been determined.
From April 2013 through October 2016, the researchers studied the population of Lihir, an island of Papua New Guinea where yaws is endemic. They found that mass azithromycin treatment followed by targeted treatment programs reduced the prevalence of active yaws from 1.8% to 0.1% at 18 months, but the infection began to re-emerge at 24 months and the prevalence climbed to 0.4% at 42 months. Most of the cases were latent infections in individuals who were absent at the time of mass treatment, but some were imported.
In addition, the researchers found five cases of yaws at months 36 and 42 that were resistant to azithromycin. Polymerase chain reaction testing indicated that the resistance was caused by mutations in the 23S ribosomal RNA gene. All the cases were from the same village, indicating infection with the same strain.
"Our study underlines the need to treat every individual living in an endemic zone, in order to cure latent infections," lead author Oriol Mitja, MD, said in a press release from the Barcelona Institute for Global Health. Mitja and his colleagues conclude that a distribution of a second or third round of azithromycin at 6 to 12 months might be of substantial benefit.
Feb 7 Lancet abstract
Feb 7 Barcelona Institute for Global Health press release
Antibiotic-resistant Campylobacter implicated in 2016 raw milk outbreak
A 17-case Campylobacter outbreak linked to raw milk in Colorado in August 2016 has been confirmed to be caused by C jejuni bacteria resistant to fluoroquinolones, a class of antibiotics often used to treat campylobacteriosis, scientists from Colorado and the Centers for Disease Control and Prevention reported today in Morbidity and Mortality Weekly Report (MMWR).
Health officials confirmed 12 cases, and 5 other were deemed probable. Patients ranged in age from 12 to 68, with a median age of 58, and 9 were male. Illnesses lasted from 3 to 10 days, and one person required hospitalization. Testing of samples from patients and unpasteurized milk from the source dairy revealed matching C jejuni pathogens.
The National Antimicrobial Resistance Monitoring System performed antimicrobial susceptibility tests on five representative isolates, and all were resistant to ciprofloxacin, tetracycline, and nalidixic acid.
The authors concluded, "All tested isolates' resistance to three antibiotics was concerning, particularly as fluoroquinolones are frequently used to treat Campylobacter infections in those cases where treatment is indicated. Treatment of antibiotic-resistant Campylobacter infections might be more difficult, of longer duration, and possibly lead to more severe illness than treatment of nonresistant Campylobacter infections." The noted that, in 2015, 25.3% of US C jejuni isolates were resistant to ciprofloxacin, an increase from 21.6% 10 years earlier.
Feb 9 MMWR report