Resistance to the main drugs used in Brazil against Leishmania is found in parasite infecting cutaneous leishmaniasis patient
Researchers in Brazil who analyzed samples from a 46-year-old patient in the Northeast state of Maranhão found an amphotericin B-resistant strain of the parasite Leishmania amazonensis circulating for the first time in the country. Amphotericin B is widely used to treat cutaneous leishmaniasis, a skin infection caused by sandfly bite.
The disease is characterized by skin lesions that persist for months but can be cured. In the case in question, however, the patient had the diffuse form of cutaneous leishmaniasis, which is rare, hard to treat, and associated with an inadequate immune response by the organism.
The patient also had HIV, which causes AIDS, making his condition even harder to combat. He had previously received treatments that were unsuccessful. The parasite was refractory to a therapeutic regimen involving the main drugs used against leishmaniasis in Brazil: meglumine antimoniate (preferred for several decades despite low efficacy) and amphotericin B (one of the few options available in Brazil for treating diffuse cutaneous leishmaniasis).
The researchers decided to find out how resistant the strain isolated from this patient was to amphotericin B by means of in vitro and in vivo trials. “We used mice infected by the isolated parasite for the in vivo model. We treated the mice with amphotericin B and two other drugs to which the patient had not been exposed: miltefosine and paromomycin,” says Adriano Cappellazzo Coelho, principal investigator for the study and a professor at the State University of Campinas’s Institute of Biology (IB-UNICAMP) in São Paulo state.
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