In vitro and in vivo susceptibility to sulfadiazine and pyrimethamine of Toxoplasma gondii strains isolated from Brazilian free wild birds

• Published in: Scientific reports Vol. 13; no. 1; p. 7359
• Main Authors: de Lima Bessa, Gabriella, Vitor, Ricardo Wagner de Almeida, Lobo, Luana Margarida Sabino, Rêgo, Wagner Martins Fontes, de Souza, Gabriela Carolina Alves, Lopes, Rosálida Estevam Nazar, Costa, Júlia Gatti Ladeia, Martins-Duarte, Erica S.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 05-05-2023; Nature Publishing Group; Nature Portfolio
• Subjects: 631/326/22/1434; 631/326/417; Antiprotozoal Agents - therapeutic use; Birds; Bradyzoites; Brazil; Drug dosages; Drug resistance; Humanities and Social Sciences; multidisciplinary; Protozoa; Pyrimethamine; Pyrimethamine - pharmacology; Pyrimethamine - therapeutic use; Science; Science (multidisciplinary); Sulfadiazine; Sulfadiazine - pharmacology; Sulfadiazine - therapeutic use; Susceptibility; Toxoplasma; Toxoplasma gondii; Variation; Brazil
• ISSN: 2045-2322; 2045-2322
• 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.