Combination of Clindamycin and Azithromycin as Alternative Treatment for Toxoplasma gondii Encephalitis

Quercetin inhibits Toxoplasma gondii tachyzoite proliferation and acts synergically with azithromycin

Quercetin (QUE) is a natural polyphenol known to have numerous pharmacological properties against infectious and non-infectious diseases. Azithromycin (AZ) is an antibiotic that belongs to the azalide class of antimicrobials and an antiparasitic that is known to be effective in combination with clindamycin against pyrimethamine/sulfadiazine-resistant Toxoplasma gondii tachyzoites in clinical settings. Both compounds are known to target protein synthesis and have anti-inflammatory properties. However, little is known about QUE and AZ synergistic interaction against T. gondii growth. Here, we report for the first time the effects of the combination of QUE and AZ on T. gondii growth. The 50% inhibitory concentration (IC50) for QUE at 72 h of interaction was determined to be 0.50 µM, whereas AZ gave an IC50 value of 0.66 µM at 72 h of interaction with parasites. Combination testing of QUE and AZ in a ratio of 2:1 (QUE:AZ) showed an IC50 value of 0.081 µM. Interestingly, a fractional inhibitory index value of 0.28 was observed, indicating a strong synergy. QUE was also found to upregulate the generation of reactive oxygen species and cause dysfunction of the mitochondria membrane of both intracellular and extracellular T. gondii tachyzoites. Overall, the results indicate that QUE is a novel lead capable of synergizing with AZ for inhibiting T. gondii growth and may merit future investigation in vivo for possible combination drug development.

Anti-Toxoplasma gondii activity of Trametes versicolor (Turkey tail) mushroom extract

Toxoplasma gondii (T. gondii) infection continues to rise globally in humans and animals with high socioeconomic and public health challenges. Current medications used against T. gondii infection are limited in efficacy, safety, and affordability. This research was conducted to assess the higher fungi extract effect on T. gondii tachyzoites growth in vitro and possibly decipher its mechanism of action. Furthermore, we evaluated the extract's effect on human foreskin fibroblast viability. The methanol extracts of Turkey tail (TT) mushroom was tested against T. gondii tachyzoites growth using an RH-RFP type I strain that expresses red fluorescent protein throughout culture in a dose-dependent manner using a fluorescent plate reader. Similarly, we tested the effect of the extract on host cell viability. We observed that TT extract inhibited tachyzoites growth with a 50% minimum inhibitory concentration (IC_50s), IC₅₀ = 5.98 ± 1.22 µg/mL, and 50% cytotoxic concentration (CC_50s), CC₅₀ ≥ 100 µg/mL. It was discovered that TT extract induced strong mitochondria superoxide and  reactive oxygen species production and disrupted mitochondria membrane potential in T. gondii tachyzoites. Additionally, scanning electron microscopy depicted that TT extract and pyrimethamine (PY) caused a morphological deformation of tachyzoites in vitro. In conclusion, TT methanol extract made up of phytosterols, bioactive sphingolipids, peptides, phenolic acids, and lactones could be a promising source of new compounds for the future development of anti-Toxoplasma gondii drugs. Extracts were non-cytotoxic, even at higher concentrations.

The use of azithromycin and pyrimethamine for treatment of cerebral toxoplasmosis in human immunodeficiency virus-infected patients: a systematic review

Purpose

Toxoplasma gondii is a parasite that is widely distributed around the globe and can cause brain inflammation, particularly in immunosuppressed patients such as those diagnosed with human immunodeficiency virus (HIV). This paper reviews the efficacy of azithromycin and pyrimethamine combination therapy for cerebral toxoplasmosis in patients with HIV.

Methods

The scope of the studies included in this review was limited from 1992 to 2022, with studies primarily being randomized, controlled clinical trials available on online scientific journal databases. The authors screened eligible records for review, removing those that did not fit the inclusion and exclusion criteria. The risk of bias of the extracted data was analyzed through the Cochrane risk-of-bias tool for randomized trials.

Results

A broad search of major online databases such as PubMed, Medline, Google Scholar, and Cochrane using keywords, limit fields, and Boolean operators yielded 3,130 articles. After thoroughly screening the search results, two studies were included in this review. Results from the studies included in the review demonstrate that the combination therapy of azithromycin and pyrimethamine is favorable for cerebral toxoplasmosis. However, the net response is less effective than the standard treatment regimen (pyrimethamine and sulfadiazine).

Conclusion

The combination therapy of azithromycin and pyrimethamine is less effective than the standard treatment regimen for maintenance therapy for cerebral toxoplasmosis; thus, administering these medications for this indication must be met with caution.

A Metabolomic and Transcriptomic Study Revealed the Mechanisms of Lumefantrine Inhibition of Toxoplasma gondii

Toxoplasma gondii is an obligate protozoon that can infect all warm-blooded animals including humans. T. gondii afflicts one-third of the human population and is a detriment to the health of livestock and wildlife. Thus far, traditional drugs such as pyrimethamine and sulfadiazine used to treat T. gondii infection are inadequate as therapeutics due to relapse, long treatment period, and low efficacy in parasite clearance. Novel, efficacious drugs have not been available. Lumefantrine, as an antimalarial, is effective in killing T. gondii but has no known mechanism of action. We combined metabolomics with transcriptomics to investigate how lumefantrine inhibits T. gondii growth. We identified significant alternations in transcripts and metabolites and their associated functional pathways that are attributed to lumefantrine treatment. RH tachyzoites were used to infect Vero cells for three hours and subsequently treated with 900 ng/mL lumefantrine. Twenty-four hours post-drug treatment, we observed significant changes in transcripts associated with five DNA replication and repair pathways. Metabolomic data acquired through liquid chromatography-tandem mass spectrometry (LC-MS) showed that lumefantrine mainly affected sugar and amino acid metabolism, especially galactose and arginine. To investigate whether lumefantrine damages T. gondii DNA, we conducted a terminal transferase assay (TUNEL). TUNEL results showed that lumefantrine significantly induced apoptosis in a dose-dependent manner. Taken together, lumefantrine effectively inhibited T. gondii growth by damaging DNA, interfering with DNA replication and repair, and altering energy and amino acid metabolisms.

Unveiling of brain transcriptome of masked palm civet (Paguma larvata) with chronic infection of Toxoplasma gondii

BACKGROUND

The aim of this study was to gain an understanding of the transcriptomic changes that occur in a wild species when infected with Toxoplasma gondii. The masked palm civet, an artifically domesticated animal, was used as the model of a wild species. Transcriptome analysis was used to study alterations in gene expression in the domesticated masked palm civet after chronic infection with T. gondii.

METHODS

Masked palm civets were infected with 10⁵ T. gondii cysts and their brain tissue collected after 4 months of infection. RNA sequencing (RNA-Seq) was used to gain insight into the spectrum of genes that were differentially expressed due to infection. Quantitative reverse-transcription PCR (qRT-PCR) was also used to validate the level of expression of a set of differentially expressed genes (DEGs) obtained by sequencing.

RESULTS

DEGs were screened from the sequencing results and analyzed. A total of 2808 DEGs were detected, of which 860 were upregulated and 1948 were downregulated. RNA-Seq results were confirmed by qRT-PCR. DEGs were mainly enriched in cellular process and metabolic process based on gene ontology enrichment analysis. Kyoto Encyclopedia of Genes and Genomes pathway analysis showed that transcriptional changes in the brain of infected masked palm civets evolved over the course of infection and that DEGs were mainly enriched in the signal transduction, immune system processes, transport and catabolic pathways. Finally, 10 essential driving genes were identified from the immune signaling pathway.

CONCLUSIONS

This study revealed novel host genes which may provide target genes for the development of new therapeutics and detection methods for T. gondii infection in wild animals.

Inhibition of Toxoplasma gondii Growth by Dihydroquinine and Its Mechanisms of Action

Toxoplasma gondii is a zoonotic parasite that infects the brain of humans and causes cerebral toxoplasmosis. The recommended drugs for the treatment or prophylaxis of toxoplasmosis are pyrimethamine (PY) and sulfadiazine (SZ), which have serious side effects. Other drugs available for toxoplasmosis are poorly tolerated. Dihydroquinine (DHQ) is a compound closely related to quinine-based drugs that have been shown to inhibit Plasmodium falciparum and Plasmodium berghei in addition to its anti-arrhythmia properties. However, little is known about the effect of DHQ in T. gondii growth and its mechanism of action in vitro. In this study, we report the anti-Toxoplasma and anti-invasion properties of DHQ. DHQ significantly inhibited T. gondii tachyzoite growth with IC50s values of 0.63, 0.67, and 0.00137 µM at 24, 48, and 72 h, respectively. Under similar conditions, SZ and PY, considered as the gold standard drugs for the treatment of toxoplasmosis, had IC50s values of 1.29, 1.55, and 0.95 and 3.19, 3.52, and 2.42 µM, respectively. The rapid dose-dependent inhibition of T. gondii tachyzoites by DHQ compared to the standard drugs (SZ and PY) indicates that DHQ has high selective parasiticidal effects against tachyzoite proliferation. Remarkably, DHQ had an excellent selectivity index (SI) of 149- and 357-fold compared to 24- and 143-fold for PY and SZ, respectively, using fibroblast cells. In addition, DHQ disrupted T. gondii tachyzoite mitochondrial membrane potential and adenosine triphosphate (ATP) production and elicited high reactive oxygen species (ROS) generation. Taking all these findings together, DHQ promises to be an effective and safe lead for the treatment of toxoplasmosis.

Study on the effect of koumiss on the intestinal microbiota of mice infected with Toxoplasma gondii

Toxoplasma gondii is a worldwide food-borne parasite that can infect almost all warm-blooded animals, including humans. To date, there are no effective drugs to prevent or eradicate T. gondii infection. Recent studies have shown that probiotics could influence the relationship between the microbiota and parasites in the host. Koumiss has been used to treat many diseases based on its probiotic diversity. Therefore, we explored the effect of koumiss on T. gondii infection via its effect on the host intestinal microbiota. BALB/c mice were infected with T. gondii and treated with PBS, koumiss and mares' milk. Brain cysts were counted, and long-term changes in the microbiota and the effect of koumiss on gut microbiota were investigated with high-throughput sequencing technology. The results suggested that koumiss treatment significantly decreased the cyst counts in the brain (P < 0.05). Moreover, T. gondii infection changed the microbiota composition, and koumiss treatment increased the relative abundance of Lachnospiraceae and Akkermansia muciniphila, which were associated with preventing T. gondii infection. Moreover, koumiss could inhibit or ameliorate T. gondii infection by increasing the abundance of certain bacteria that control unique metabolic pathways. The study not only established a close interaction among the host, intracellular pathogens and intestinal microbiota but also provided a novel focus for drug development to prevent and eradicate T. gondii infection.

Toxoplasma gondii in humans and animals in Japan: An epidemiological overview

Toxoplasmosis is a cosmopolitan protozoan zoonosis caused by Toxoplasma gondii infamous for inducing severe clinical manifestations in humans. Although the disease affects at least one billion people worldwide, it is neglected in many countries including developed ones. In literature, the epidemiological data documenting the actual incidence of the disease in humans and domestic animals from Japan are limited and importantly many earlier papers on T. gondii infections were published in Japanese and a considerable part is not available online. Herein, we review the current summary about the epidemiological situation of T. gondii infection in Japan and the potential associated risk factors in humans and animals as well as the different T. gondii genotypes isolated in Japan. Several T. gondii isolates have been identified among cats (TgCatJpTy1/k-3, TgCatJpGi1/TaJ, TgCatJpObi1 and TgCatJpOk1-4) and goats (TgGoatJpOk1-13). This literature review underscores the need for a nationwide investigation of T. gondii infection in Japanese people and assessment of the socioeconomic impact of the disease burden. Furthermore, epidemiological studies in domestic and wild animals and estimation of degree of contamination of soil or water with T. gondii oocysts are needed, for a better understanding of the scope of this public health concern.

Treatment of toxoplasmic encephalitis with the combination of clindamycin plus azithromycin in an HIV-infected patient: A case report

The existence of alternative oral therapies could help clinicians to treat toxoplasmic encephalitis (TE) in the HIV patients. The combination of azithromycin and clindamycin may serve as an effective treatment for TE in HIV-infected patients.

Transcriptomic Profiling of Mouse Brain During Acute and Chronic Infections by Toxoplasma gondii Oocysts

Infection by the protozoan Toxoplasma gondii can have a devastating impact on the structure and function of the brain of the infected individuals, particularly immunocompromised patients. A systems biology view of the brain transcriptome can identify key molecular targets and pathways that mediate the neuropathogenesis of cerebral toxoplasmosis. Here, we performed transcriptomic analysis of the brain of mice infected by T. gondii Pru strain oocysts at 11 and 33 days post-infection (dpi) compared to uninfected (control) mice using RNA sequencing (RNA-seq). T. gondii altered the expression of 936 and 2,081 transcripts at 11 and 33 dpi, respectively, and most of these were upregulated in the infected brains. Gene Ontology (GO) enrichment and pathway analysis showed that immune response, such as interferon-gamma (IFN-γ) responsive genes were strongly affected at 11dpi. Likewise, differentially expressed transcripts (DETs) related to T cell activation, cytokine production and immune cell proliferation were significantly altered at 33 dpi. Host-parasite interactome analysis showed that some DETs were involved in immune signaling, metabolism, biosynthesis-related processes and interspecies interaction. These findings should increase knowledge of the mouse brain transcriptome and the changes in transcriptional regulation and downstream signaling pathways during acute and chronic T. gondii infections.

Antimalarial Agents as Therapeutic Tools Against Toxoplasmosis-A Short Bridge between Two Distant Illnesses

Toxoplasmosis is an infectious disease with paramount impact worldwide, affecting many vulnerable populations and representing a significant matter of concern. Current therapies used against toxoplasmosis are based essentially on old chemotypes, which fail in providing a definitive cure for the disease, placing the most sensitive populations at risk for irreversible damage in vital organs, culminating in death in the most serious cases. Antimalarial drugs have been shown to possess key features for drug repurposing, finding application in the treatment of other parasite-borne illnesses, including toxoplasmosis. Antimalarials provide the most effective therapeutic solutions against toxoplasmosis and make up for the majority of currently available antitoxoplasmic drugs. Additionally, other antiplasmodial drugs have been scrutinized and many promising candidates have emanated in recent developments. Available data demonstrate that it is worthwhile to explore the activity of classical and most recent antimalarial chemotypes, such as quinolines, endoperoxides, pyrazolo[1,5-a]pyrimidines, and nature-derived peptide-based parasiticidal agents, in the context of toxoplasmosis chemotherapy, in the quest for encountering more effective and safer tools for toxoplasmosis control or eradication.

Rosuvastatin reduced brain parasite burden in a chronic toxoplasmosis in vivo model and influenced the neuropathological pattern of ME-49 strain

This study evaluated the effects of rosuvastatin in vivo on toxoplasmosis chronic infection. Thirty-five Swiss mice were orally infected (ME-49 strain). After 50 days, the mice were separated into five groups: GI - non-infected, GII - infected, GIII - infected and treated with pyrimethamine and sulfadiazine (12.5 + 50 mg kg-1 body weight day-1), GIV and GV - infected and treated with rosuvastatin 10 and 40 mg kg-1 body weight day-1, respectively. After 21 days, we collected blood, liver, lungs, femoral biceps and brain were removed for Toxoplasma gondii DNA quantification by qPCR and histopathological analysis. GIV and GV did not present premature death or clinical changes, and the hepatic enzyme levels were lower compared to GI. Toxoplasma gondii DNA was detected mainly in brain and muscle, but the parasite load was significantly lower in GV compared to GII brains (P < 0.05). Histopathological changes were observed in brains, with T. gondii cysts as well as an inflammatory condition, including necrosis areas in GII and GIII. These data confirm active infection with tissue injury. This inflammatory condition was attenuated in the groups treated with rosuvastatin, especially R40 (GV). Our findings demonstrated the in vivo action of rosuvastatin in reducing cerebral parasitic load and indicate that this drug may interfere in chronic toxoplasmosis.