Treatment Strategy in Human Ocular Toxoplasmosis: Why Antibiotics Have Failed

Abstract

Background: There is currently no clear evidence of the effectiveness of antibiotic therapy in acute ocular toxoplasmosis (OT), but its effect as a secondary prophylaxis is undisputed. The majority of uveitis specialists advocate treatment. This meta-analytic review aims to critically analyze determinants of treatment success and to update current treatment strategies for OT in order to explain this discrepancy. Methods: A systematic literature search was performed in NCBI/PubMed, Clinical Trials, Google Scholar and ScienceDirect to retrieve pro- and retrospective studies using the key terms “ocular toxoplasmosis” or “retinochoroiditis” and “immunocompetent” and “treatment” or “therapy” and “human.” Of these, larger case series and prospective clinical studies and cross references identified from meta-analyses were selected by a manual search, and primary and secondary outcome parameters were extracted. Results: Ten case series and clinical trials reported success parameters for treatment outcomes, and four additional for recurrence prophylaxis. Five treatment studies were randomized clinical trials, three comparative and two noncomparative case series. Though several outcome parameters were reported, five of them defined time to healing, four visual gain and one lesion size as primary and secondary outcome parameters, recurrence rate as a secondary outcome parameter was reported once. No conclusive evidence was found for an antibiotic treatment effect. Four prophylaxis studies addressed the prevention of recurrences after treatment. The primary outcome in all studies was the effect of treatment and prophylaxis on recurrences, and all four found a significant effect on the risk of and time to recurrences. Conclusions: Antibiotic treatment of OT aims at controlling parasite proliferation. The absence of an effect on visual acuity and time to healing is thus not surprising. The fact that time to and number of recurrences respond to recurrence of prophylaxis proves the antibiotic effect on parasite activity.

Toxoplasmosis is a risk factor for acquiring SARS-CoV-2 infection and a severe course of COVID-19 in the Czech and Slovak population: a preregistered exploratory internet cross-sectional study

“…Latent toxoplasmosis has long been considered asymptomatic in immunocompetent individuals, which is why no effort has been invested in finding a drug that would kill the bradyzoites in cysts and treat latent toxoplasmosis. This attitude is now slowly changing [ 4 ]. For example, ocular toxoplasmosis, an important cause of infectious uveitis, was believed to be associated with the relatively rare congenital toxoplasmosis [ 5 ], but current data strongly suggest that it is a relatively common effect of postnatally acquired toxoplasmosis, the most common form of toxoplasmosis.…”

Fluocinolone acetonide implant in diabetic macular edema: International experts’ panel consensus guidelines and treatment algorithm

“…When treating toxoplasmic retinochoroiditis or herpetic keratouveitis for example, administration of antibiotics or antiviral drugs aims at reducing the frequency and severity of recurrences, while steroids are used to quickly control the inflammation. 63,64 Injection of a FAc implant for DME provides a similar advantage over a prolonged period of time, but may require an association with a steroid achieving acutely a higher dose. 35,37,42 If DME relapses after the first 24 months, a second injection of FAc implant should rather be considered, as in some eyes, the evolution rate of the drug may be faster.…”

Infektiöse posteriore Uveitis – Toxoplasmose, Treponema, Tuberkulose (TTT)

“…Die Therapie der okulären Toxoplasmose ist jedoch nicht in jedem Fall erforderlich. Allgemein gelten Herde, die Sehnerv oder Makula bedrohen, eine starke Glaskörperinfiltration oder sehr große periphere Herde als Indikation für eine antiinfektiöse Therapie der okulären Toxoplasmose 4 , 11 , 17 , 18 , 19 , 20 , 21 , 22 . Tab.…”

“…However, it is not always necessary to treat ocular toxoplasmosis. In general, foci threatening the optic nerve or macula, severe vitreous infiltration, or very large peripheral foci are considered indications for anti-infective treatment of ocular toxoplasmosis 4 , 11 , 17 , 18 , 19 , 20 , 21 , 22 . Table 1 lists the most commonly used drugs.…”