Treatment of presumed cerebral toxoplasmosis with azithromycin

Licochalcone A: An effective and low-toxicity compound against Toxoplasma gondii in vitro and in vivo

Toxoplasma gondii, an obligate intracellular protozoan, is the causative agent of toxoplasmosis, which can cause serious public health problems. The current drugs used to treat toxoplasmosis have many limitations. This study evaluated the anti-T. gondii activity and potential mechanism of Licochalcone A (Lico A) in vitro and in vivo. The safe concentration of Lico A in HFF cells was determined by MTT cell viability assays. The presence of T. gondii was assessed by qPCR and Giemsa staining. Azithromycin and sulfadiazine, commonly used effective treatments, served as drug controls. T. gondii ultrastructural alterations were observed by electron microscopy. The anti-T. gondii activity of Lico A was evaluated using an in vivo mouse infection model. In vitro, Lico A had no negative effect on host cell viability at concentrations below 9 μg/mL; however, it did inhibit T. gondii proliferation in a dose-dependent manner, with a 50% inhibitory concentration (IC₅₀) of 0.848 μg/mL. Electron microscopy analyses indicated substantial structural and ultrastructural changes in tachyzoites after Lico A treatment. Nile Red staining assays demonstrated that Lico A caused lipid accumulation. Lico A treatment significantly increased the survival rate of BALB/c mice infected with T. gondii. Lico A achieved the same therapeutic effect as a commonly used clinical drugs (combination of sulfadiazine, pyrimethamine and folinic acid). In conclusion, Lico A has strong anti-T. gondii activity in vitro and in vivo and might be developed into a new anti-T. gondii drug. Moreover, Lico A may exert these effects by interfering with lipid metabolism in the parasite.

Avaliação da eficácia da azitromicina e pirimetamina em camundongos infectados por cepa cistogênica de Toxoplasma gondii

Foi avaliada a eficácia da administração prolongada de azitromicina e pirimetamina em camundongos infectados com cepa cistogênica de Toxoplasma gondii. Os animais foram inoculados intraperitonealmente com um cisto de T. gondii e, após 20 dias, divididos em quatro grupos: GI infectados não tratados, GII infectados e tratados concomitantemente com pirimetamina (12,5mg/kg/dia) e azitromicina (100mg/kg/dia), GIII infectados e tratados com a mesma dose de pirimetamina e GIV infectados e tratados da mesma forma com azitromicina. O tratamento, via oral, estendeu-se por 120 dias; após este período os animais foram sacrificados e foi feita a contagem dos cistos no cérebro. A associação de ambos os medicamentos proporcionou melhores resultados, diminuindo a contagem de cistos no cérebro dos animais tratados de forma concomitante.

Maternal and transplacental pharmacokinetics of azithromycin

OBJECTIVE

The purpose of this study was to characterize the pharmacokinetics of orally administered azithromycin in the term gravid woman.

STUDY DESIGN

Twenty women who were scheduled for elective cesarean delivery were enrolled prospectively and received 1 g of oral azithromycin at either 6, 12, 24, 72, or 168 hours before the operation. All women received spinal anesthesia, at which time a sample of cerebrospinal fluid was obtained for analysis. Maternal serum and urine were obtained immediately before the operation. Intraoperatively, samples of myometrium, maternal adipose tissue, placenta, amniotic fluid, and umbilical arterial and venous cord blood were obtained. Azithromycin levels were determined quantitatively with high-pressure liquid chromatography with electrochemical detection.

RESULTS

All participants tolerated the preoperative azithromycin without significant adverse reactions. Peak maternal serum azithromycin levels occurred within 6 hours of drug administration. Although high serum levels of azithromycin were reached early, a rapid decline in drug concentration was noted over the initial 24 hours after the drug administration (6-hour: 311 ng/mL; 24-hour: 63 ng/mL). In contrast, azithromycin levels in myometrial, adipose, and placental tissue were higher (>500 ng/mL) and sustained for up to 72 hours after administration. High urine levels of azithromycin (>5000 ng/mL) were noted similarly during the initial 72 hours after drug administration. Umbilical arterial and venous serum azithromycin levels were low (19-38 ng/mL) during the first 72 hours. Amniotic fluid levels were highest at 6 hours (151 ng/mL) and declined rapidly. Maternal cerebrospinal azithromycin concentrations were undetectable for all time points.

CONCLUSION

Azithromycin has a rapid serum half-life in the term gravid woman with a prolonged half-life and high-sustained antibiotic levels noted within myometrium, adipose, and placental tissue. Given the broad antimicrobial spectrum and placental penetration, azithromycin may have potential use for the treatment of perinatal infections.

[The evaluation of the efficacy of azithromycin and pyrimethamine used alone or in combination in the treatment of an experimental infection in mice by Toxoplasma gondii]

The efficacy of azithromycin and pyrimethamine in experimental infection of mice with Toxoplasma gondii was tested. Daily dosages of 200 mg/kg and 12.5 mg/kg, respectively, were given orally over a period of ten days. The medications were administered in combination or separately. The combined use of the drugs yielded better results, and a similar investigation using a cystogenic strain of the parasite will be conducted in a future study.

Toxoplasmosis and parvovirus B19

Pregnant women might well improve their chances for a successful pregnancy outcome by following the advice of W. C. Fields: avoid contact with small children and animals whenever possible. Failing widespread acceptance of this philosophy, management of T. gondii and parvovirus B19 infections continues to be a challenge for the foreseeable future.