Clinical Characteristics, Histopathology, and Treatment Outcomes of Pythium Keratitis: A Retrospective Cohort Study

Puangsricharern, Vilavun; Chotikkakamthorn, Patraramon; Tulvatana, Wasee; Kittipibul, Thanachaporn; Chantaren, Patchima; Reinprayoon, Usanee; Kasetsuwan, Ngamjit; Satitpitakul, Vannarut; Worasilchai, Navaporn; Chindamporn, Ariya

doi:10.2147/opth.s303721

Cited by 27 publications

(29 citation statements)

References 25 publications

(55 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Similar to vascular pythiosis, surgical intervention is also the primary option for treating ocular pythiosis [132,150,167,177,180,181,184,185]. Topical or systemic antimicrobial agents (including linezolid, azithromycin, itraconazole, terbinafine, amphotericin B, natamycin, moxifloxacin, and minocycline) were administered in the ocular cases [97,106,174,[180][181][182]186,187]. In addition, many ocular pythiosis patients underwent penetrating keratoplasty to save the affected eye [53,54,91,165,166,168,170,173,176,183].…”

Section: Clinical Application Of Immunotherapy In Human Pythiosismentioning

confidence: 99%

“…Post-keratoplasty recurrent infection resulted in eye removal by evisceration or enucleation [66,91,150,176,184]. In addition to the surgical and medical treatments, PIA was administered to modulate the immune response in 35 out of 168 ocular pythiosis patients (20.8%; one of which had bilateral ocular infections) [1,106,127,132,150,180] and 2 out of 5 periorbital pythiosis patients (40.0%) [43,160] (Table 2). The affected eye was removed in 17 out of 35 PIA-immunized (48.6%) and 47 out of 133 PIA-unimmunized (35.3%) patients (Table 2).…”

Section: Clinical Application Of Immunotherapy In Human Pythiosismentioning

confidence: 99%

“…Administration of the PIA immunotherapy for pythiosis patients (i.e., antigen concentration, injection site, number of doses, and duration between shots) can differ based on the clinician's judgment and PIA availability. The immunotherapeutic PIA is generally prepared to the final concentration of 2 mg/mL [90,106,107,127,131,132,151,180]. Either 0.1-0.2 mL [43,106,107,131,132] or 1.0 mL [90,106,109,151,180] of PIA per dose is injected subcutaneously at least 2 times: initial and subsequent time points (i.e., 0.5, 1, 1.5, 3, 6, and 12 months) [13,43,61,106,107,109,127,131,132,149,151,180].…”

Section: Clinical Application Of Immunotherapy In Human Pythiosismentioning

confidence: 99%

“…The immunotherapeutic PIA is generally prepared to the final concentration of 2 mg/mL [90,106,107,127,131,132,151,180]. Either 0.1-0.2 mL [43,106,107,131,132] or 1.0 mL [90,106,109,151,180] of PIA per dose is injected subcutaneously at least 2 times: initial and subsequent time points (i.e., 0.5, 1, 1.5, 3, 6, and 12 months) [13,43,61,106,107,109,127,131,132,149,151,180]. In some cases, the first PIA dose was provided intradermally [106,131].…”

Section: Clinical Application Of Immunotherapy In Human Pythiosismentioning

confidence: 99%

“…The PIA immunotherapy shows a favorable response in some humans and animals with pythiosis [46,106,[129][130][131]180]. The mechanism of PIA action in pythiosis treatment is not clearly understood.…”

Section: Proposed Mechanism Of P Insidiosum Antigen-based Immunotherapymentioning

confidence: 99%

See 4 more Smart Citations

History and Perspective of Immunotherapy for Pythiosis

Yolanda

Krajaejun

2021

Vaccines

View full text Add to dashboard Cite

The fungus-like microorganism Pythium insidiosum causes pythiosis, a life-threatening infectious disease increasingly reported worldwide. Antimicrobial drugs are ineffective. Radical surgery is an essential treatment. Pythiosis can resume post-surgically. Immunotherapy using P. insidiosum antigens (PIA) has emerged as an alternative treatment. This review aims at providing up-to-date information of the immunotherapeutic PIA, with the focus on its history, preparation, clinical application, outcome, mechanism, and recent advances, in order to promote the proper use and future development of this treatment modality. P. insidiosum crude extract is the primary source of immunotherapeutic antigens. Based on 967 documented human and animal (mainly horses) pythiosis cases, PIA immunotherapy reduced disease morbidity and mortality. Concerning clinical outcomes, 19.4% of PIA-immunized human patients succumbed to vascular pythiosis instead of 41.0% in unimmunized cases. PIA immunotherapy may not provide an advantage in a local P. insidiosum infection of the eye. Both PIA-immunized and unimmunized horses with pythiosis showed a similar survival rate of ~70%; however, demands for surgical intervention were much lesser in the immunized cases (22.8% vs. 75.2%). The proposed PIA action involves switching the non-protective T-helper-2 to protective T-helper-1 mediated immunity. By exploring the available P. insidiosum genome data, synthetic peptides, recombinant proteins, and nucleic acids are potential sources of the immunotherapeutic antigens worth investigating. The PIA therapeutic property needs improvement for a better prognosis of pythiosis patients.

show abstract

Section: Clinical Application Of Immunotherapy In Human Pythiosismentioning

confidence: 99%

Section: Clinical Application Of Immunotherapy In Human Pythiosismentioning

confidence: 99%

Section: Clinical Application Of Immunotherapy In Human Pythiosismentioning

confidence: 99%

Section: Clinical Application Of Immunotherapy In Human Pythiosismentioning

confidence: 99%

Section: Proposed Mechanism Of P Insidiosum Antigen-based Immunotherapymentioning

confidence: 99%

See 3 more Smart Citations

History and Perspective of Immunotherapy for Pythiosis

Yolanda

Krajaejun

2021

Vaccines

View full text Add to dashboard Cite

show abstract

Pythium insidiosum Keratitis: Past, Present, and Future

et al. 2022

View full text Add to dashboard Cite

Pythium insidiosum (PI) is an oomycete, a protist belonging to the clade Stramenopila. PI causes vision-threatening keratitis closely mimicking fungal keratitis (FK), hence it is also labeled as “parafungus”. PI keratitis was initially confined to Thailand, USA, China, and Australia, but with growing clinical awareness and improvement in diagnostic modalities, the last decade saw a massive upsurge in numbers with the majority of reports coming from India. In the early 1990s, pythiosis was classified as vascular, cutaneous, gastrointestinal, systemic, and ocular. Clinically, morphologically, and microbiologically, PI keratitis closely resembles severe FK and requires a high index of clinical suspicion for diagnosis. The clinical features such as reticular dot infiltrate, tentacular projections, peripheral thinning with guttering, and rapid limbal spread distinguish it from other microorganisms. Routine smearing with Gram and KOH stain reveals perpendicular septate/aseptate hyphae, which closely mimic fungi and make the diagnosis cumbersome. The definitive diagnosis is the presence of dull grey/brown refractile colonies along with zoospore formation upon culture by leaf induction method. However, culture is time-consuming, and currently polymerase chain reaction (PCR) method is the gold standard. The value of other diagnostic modalities such as confocal microscopy and immunohistopathological assays is limited due to cost, non-availability, and limited diagnostic accuracy. PI keratitis is a relatively rare disease without established treatment protocols. Because of its resemblance to fungus, it was earlier treated with antifungals but with an improved understanding of its cell wall structure and absence of ergosterol, this is no longer recommended. Currently, antibacterials have shown promising results. Therapeutic keratoplasty with good margin (1 mm) is mandated for non-resolving cases and corneal perforation. In this review, we have deliberated on the evolution of PI keratitis, covered all the recently available literature, described our current understanding of the diagnosis and treatment, and the potential future diagnostic and management options for PI keratitis.

show abstract