Laboratório de Toxoplasmose, Departamento de Parasitologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
Laboratório de Quimioterapia de Protozoários Egler Chiari, Departamento de Parasitologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Pampulha, Belo Horizonte, Minas Gerais, 31270-901, Brazil.
Sci Rep. 2023 May 5;13(1):7359. doi: 10.1038/s41598-023-34502-3.
Little is known about the existence of drug-resistant Toxoplasma gondii strains and their possible impact on clinic outcomes. To expand our knowledge about the existence of natural variations on drug susceptibility of T. gondii strains in Brazil, we evaluated the in vitro and in vivo susceptibility to sulfadiazine (SDZ) and pyrimethamine (PYR) of three atypical strains (Wild2, Wild3, and Wild4) isolated from free-living wild birds. In vitro susceptibility assay showed that the three strains were equally susceptible to SDZ and PYR but variations in the susceptibility were observed to SDZ plus PYR treatment. Variations in the proliferation rates in vitro and spontaneous conversion to bradyzoites were also accessed for all strains. Wild2 showed a lower cystogenesis capacity compared to Wild3 and Wild4. The in vivo analysis showed that while Wild3 was highly susceptible to all SDZ and PYR doses, and their combination, Wild2 and Wild4 showed low susceptibility to the lower doses of SDZ or PYR. Interestingly, Wild2 presented low susceptibility to the higher doses of SDZ, PYR and their combination. Our results suggest that the variability in treatment response by T. gondii isolates could possibly be related not only to drug resistance but also to the strain cystogenesis capacity.
关于耐药性弓形虫菌株的存在及其对临床结果的可能影响，人们知之甚少。为了扩大我们对巴西弓形虫菌株对药物敏感性的天然变异的了解，我们评估了从自由生活的野生鸟类中分离出的三种非典型菌株（Wild2、Wild3 和 Wild4）对磺胺嘧啶（SDZ）和乙胺嘧啶（PYR）的体外和体内敏感性。体外药敏试验表明，这三种菌株对 SDZ 和 PYR 同样敏感，但对 SDZ 加 PYR 治疗的敏感性存在差异。还评估了所有菌株的体外增殖率和自发转化为缓殖子的差异。与 Wild3 和 Wild4 相比，Wild2 的囊胞形成能力较低。体内分析表明，虽然 Wild3 对所有 SDZ 和 PYR 剂量及其组合均高度敏感，但 Wild2 和 Wild4 对较低剂量的 SDZ 或 PYR 敏感性较低。有趣的是，Wild2 对较高剂量的 SDZ、PYR 及其组合表现出较低的敏感性。我们的结果表明，弓形虫分离株的治疗反应的可变性可能不仅与耐药性有关，还与菌株的囊胞形成能力有关。
