Single-Dose Azithromycin for the Treatment of Haemophilus ducreyi Skin Ulcers in Papua New Guinea

Background

Haemophilus ducreyi (HD) and Treponema pallidum subspecies pertenue (TP) are major causative agents of cutaneous ulcer (CU) in the tropics. Azithromycin is recommended to treat sexually transmitted HD infections and has good in vitro activity against HD strains from both genital and skin ulcers. We investigated the efficacy of oral single-dose azithromycin on HD-CU.

Methods

We conducted a community-based cohort study in Lihir Island, Papua New Guinea, from October 2014 through May 2016. Consenting patients with skin ulcers >1 cm in diameter were eligible for this study and had collected a lesional swab for polymerase chain reaction (PCR). All participants were treated with single-dose azithromycin (30 mg/kg) and were followed up for assessment of clinical resolution. We retrospectively classified patients according to PCR results into HD, TP, and PCR-negative groups. The primary endpoint was healing rates of HD-CU at 14 days after treatment.

Results

We obtained full outcome data from 246 patients; 131 (53.3%) were HD PCR positive, 37 (15.0%) were TP positive, and 78 (31.7%) were negative for all tests. Healing rates were 88.5% (95% confidence interval [CI], .82-.93) in the HD group, 78.4% [95% CI, .63-.89] in the TP group, and 74.4% (95% CI, .64-.83) in the PCR-negative group. If we included the participants with improved ulcers, the healing rates increased to 94.7%, 97.3%, and 89.7% respectively. HD cases classified as not healed all converted to HD-negative PCR.

Conclusions

Based upon clinical resolution and PCR conversion to HD negative, a single oral dose of azithromycin is efficacious for the treatment of HD-CU. These results have implications for the treatment of individual patients and for the use of antibiotics in public health strategies to control CU in the tropics.

Re-emergence of yaws after single mass azithromycin treatment followed by targeted treatment: a longitudinal study

BACKGROUND

Yaws is a substantial cause of chronic disfiguring ulcers in children in at least 14 countries in the tropics. WHO's newly adopted strategy for yaws eradication uses a single round of mass azithromycin treatment followed by targeted treatment programmes, and data from pilot studies have shown a short-term significant reduction of yaws. We assessed the long-term efficacy of the WHO strategy for yaws eradication.

METHODS

Between April 15, 2013, and Oct 24, 2016, we did a longitudinal study on a Papua New Guinea island (Lihir; 16 092 population) in which yaws was endemic. In the initial study, the participants were followed for 12 months; in this extended follow-up study, clinical, serological, and PCR surveys were continued every 6 months for 42 months. We used genotyping and travel history to identify importation events. Active yaws confirmed by PCR specific for Treponema pallidum was the primary outcome indicator. The study is registered with ClinicalTrials.gov, number NCT01955252.

FINDINGS

Mass azithromycin treatment (coverage rate of 84%) followed by targeted treatment programmes reduced the prevalence of active yaws from 1·8% to a minimum of 0·1% at 18 months (difference from baseline -1·7%, 95% CI, -1·9 to -1·4; p<0·0001), but the infection began to re-emerge after 24 months with a significant increase to 0·4% at 42 months (difference from 18 months 0·3%, 95% CI 0·1 to 0·4; p<0·0001). At each timepoint after baseline, more than 70% of the total community burden of yaws was found in individuals who had not had the mass treatment or as new infections in non-travelling residents. At months 36 and 42, five cases of active yaws, all from the same village, showed clinical failure following azithromycin treatment, with PCR-detected mutations in the 23S ribosomal RNA genes conferring resistance to azithromycin. A sustained decrease in the prevalence of high-titre latent yaws from 13·7% to <1·5% in asymptomatic children aged 1-5 years old and of genetic diversity of yaws strains from 0·139 to less than 0·046 between months 24 and 42 indicated a reduction in transmission of infection.

INTERPRETATION

The implementation of the WHO strategy did not, in the long-term, achieve elimination in a high-endemic community mainly due to the individuals who were absent at the time of mass treatment in whom yaws reactivated; repeated mass treatment might be necessary to eliminate yaws. To our knowledge, this is the first report of the emergence of azithromycin-resistant T p pertenue and spread within one village. Communities' surveillance should be strengthened to detect any possible treatment failure and biological markers of resistance.

FUNDING

ISDIN laboratories, Newcrest Mining Limited, and US Public Health Service National Institutes of Health.

Effectiveness of single-dose azithromycin to treat latent yaws: a longitudinal comparative cohort study

BACKGROUND

Treatment of latent yaws is a crucial component of the WHO yaws eradication strategy to prevent relapse and the resulting transmission to uninfected children. We assessed the effectiveness of single-dose azithromycin to treat patients with latent yaws.

METHODS

This population-based cohort study included children (age <20 years) living on Lihir Island, Papua New Guinea, with high-titre (rapid plasma reagin titre ≥1:8) latent or active yaws, between April, 2013, and May, 2015. Latent yaws was defined as lack of suspicious skin lesions or presence of ulcers negative for Treponema pallidum subsp pertenue on PCR, and active yaws was defined as ulcers positive for T pertenue on PCR. All children received one oral dose of 30 mg/kg azithromycin. The primary endpoint was serological cure, defined as a two-dilution decrease in rapid plasma reagin titre by 24 months after treatment. Treatment of latent yaws was taken to be non-inferior to that of active yaws if the lower limit of the two-sided 95% CI for the difference in rates was higher than or equal to -10%. This study is registered with ClinicalTrials.gov, number NCT01955252.

FINDINGS

Of 311 participants enrolled, 273 (88%; 165 with latent yaws and 108 with active yaws) completed follow-up. The primary endpoint was achieved in 151 (92%) participants with latent yaws and 101 (94%) with active yaws (risk difference -2·0%, 95% CI -8·3 to 4·3), meeting the prespecified criteria for non-inferiority.

INTERPRETATION

On the basis of decline in serological titre, oral single-dose azithromycin was effective in participants with latent yaws. This finding supports the WHO strategy for the eradication of yaws based on mass administration of the entire endemic community irrespective of clinical status.

FUNDING

Newcrest Mining Limited and ISDIN laboratories.

Haemophilus ducreyi DNA is detectable on the skin of asymptomatic children, flies and fomites in villages of Papua New Guinea

BACKGROUND

Haemophilus ducreyi and Treponema pallidum subsp. pertenue are major causes of leg ulcers in children in Africa and the Pacific Region. We investigated the presence of DNA (PCR positivity) from these bacteria on asymptomatic people, flies, and household linens in an endemic setting.

METHODOLOGY/PRINCIPAL FINDINGS

We performed a cross-sectional study in rural villages of Lihir Island, Papua New Guinea during a yaws elimination campaign. Participants were asymptomatic subjects recruited from households with cases of leg ulcers, and from households without cases of leg ulcers. We rubbed swabs on the intact skin of the leg of asymptomatic individuals, and collected flies and swabs of environmental surfaces. All specimens were tested by PCR for H. ducreyi and T. p. pertenue DNA. Of 78 asymptomatic participants that had an adequate specimen for DNA detection, H. ducreyi-PCR positivity was identified in 16 (21%) and T. p. pertenue-PCR positivity in 1 (1%). In subgroup analyses, H. ducreyi-PCR positivity did not differ in participants exposed or not exposed to a case of H. ducreyi ulcer in the household (24% vs 18%; p = 0.76). Of 17 cultures obtained from asymptomatic participants, 2 (12%) yielded a definitive diagnosis of H. ducreyi, proving skin colonization. Of 10 flies tested, 9 (90%) had H. ducreyi DNA and 5 (50%) had T. p. pertenue DNA. Of 6 bed sheets sampled, 2 (33%) had H. ducreyi DNA and 1 (17%) had T. p. pertenue DNA.

CONCLUSIONS/SIGNIFICANCE

This is the first time that H. ducreyi DNA and colonization has been demonstrated on the skin of asymptomatic children and that H. ducreyi DNA and T. p. pertenue DNA has been identified in flies and on fomites. The ubiquity of H. ducreyi in the environment is a contributing factor to the spread of the organism.

Mass treatment with single-dose azithromycin for yaws

BACKGROUND

Mass treatment with azithromycin is a central component of the new World Health Organization (WHO) strategy to eradicate yaws. Empirical data on the effectiveness of the strategy are required as a prerequisite for worldwide implementation of the plan.

METHODS

We performed repeated clinical surveys for active yaws, serologic surveys for latent yaws, and molecular analyses to determine the cause of skin ulcers and identify macrolide-resistant mutations before and 6 and 12 months after mass treatment with azithromycin on a Papua New Guinean island on which yaws was endemic. Primary-outcome indicators were the prevalence of serologically confirmed active infectious yaws in the entire population and the prevalence of latent yaws with high-titer seroreactivity in a subgroup of children 1 to 15 years of age.

RESULTS

At baseline, 13,302 of 16,092 residents (82.7%) received one oral dose of azithromycin. The prevalence of active infectious yaws was reduced from 2.4% before mass treatment to 0.3% at 12 months (difference, 2.1 percentage points; P<0.001). The prevalence of high-titer latent yaws among children was reduced from 18.3% to 6.5% (difference, 11.8 percentage points; P<0.001) with a near-absence of high-titer seroreactivity in children 1 to 5 years of age. Adverse events identified within 1 week after administration of the medication occurred in approximately 17% of the participants, included nausea, diarrhea, and vomiting, and were mild in severity. No evidence of emergence of resistance to macrolides against Treponema pallidum subspecies pertenue was seen.

CONCLUSIONS

The prevalence of active and latent yaws infection fell rapidly and substantially 12 months after high-coverage mass treatment with azithromycin, with the reduction perhaps aided by subsequent activities to identify and treat new cases of yaws. Our results support the WHO strategy for the eradication of yaws. (Funded by Newcrest Mining and International SOS; YESA-13 ClinicalTrials.gov number, NCT01955252.).