Pathogenicity and phenotypic sulfadiazine resistance of Toxoplasma gondii isolates obtained from livestock in northeastern Brazil

Toxoplasma gondii is the causative protozoan agent of toxoplasmosis, which is a common infection that is widely distributed worldwide. Studies revealed stronger clonal strains in North America and Europe and genetic diversity in South American strains. Our study aimed to differentiate the pathogenicity and sulfadiazine resistance of three T. gondii isolates obtained from livestock intended for human consumption. The cytopathic effects of the T. gondii isolates were evaluated. The pathogenicity was determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) using a CS3 marker and in a rodent model in vivo. Phenotypic sulfadiazine resistance was measured using a kinetic curve of drug activity in Swiss mice. IgM and IgG were measured by ELISA, and the dihydropteroate synthase (DHPS) gene sequence was analysed. The cytopathic effects and the PCR-RFLP profiles from chickens indicated a different infection source. The Ck3 isolate displayed more cytopathic effects in vitro than the Ck2 and ME49 strains. Additionally, the Ck2 isolate induced a differential humoral immune response compared to ME49. The Ck3 and Pg1 isolates, but not the Ck2 isolate, showed sulfadiazine resistance in the sensitivity assay. We did not find any DHPS gene polymorphisms in the mouse samples. These atypical pathogenicity and sulfadiazine resistance profiles were not previously reported and served as a warning to local health authorities.

Resistance of Enterobacter cloacae and Its Gene of Chlorhexidine-sulfadiazine-resistance(qacE△1-sul1) / 中华医院感染学杂志

OBJECTIVE To investigate the resistance of Enterobacter cloacae and its gene of chlorhexidine-sulfadiazine-resistance(qacE△1-sul1) isolated from two hospitals. METHODS Microdilute tests were performed to detect the susceptibility of 20 kinds of antimicrobial agents in 74 strains of E.cloacae.The qacE△1-sul1gene was detected by PCR. RESULTS There was no strain resistant to imipenem and meropenem.The resistant rates to other antimicrobial agents were between 44.6% and 94.6%.The positive rate of qacE△1-sul1gene was 74.3%. CONCLUSIONS The 74 strains were multiple-drug-resistant.There was a high positive rate of qacE△1-sul1gene in E.cloacae isolated from two hospitals.