Clinical and experimental keratitis due to<i>Curvularia lunata</i>(Wakker) Boedijn var.<i>Aeria</i>(Batista, lima and vasconcelos) Ellis

Agrawal, Pawan K.; B, Lal; Shukla, P.K.; Khan, Z.A.; Srivastava, O. P.

doi:10.1080/00362178285380331

“…This may be attributed to disturbance in the microbial flora of the eye and local immunosuppression that probably helps the saprophytic fungi to become pathogenic. Corticosteroids as immuno‐suppressive agent have been used by several investigators to establish animal models of mycotic keratitis 66,67 . Pretreatment with another immuno‐suppressive agent cyclophosphamide is known to induce immuno‐suppression within ocular tissues that lead to increased severity and prolonged fungal persistence in a mouse model of fungal corneal ulcer 68,69 .…”

Section: Predisposing Factorsmentioning

confidence: 99%

“…Corticosteroids as immuno-suppres- sive agent have been used by several investigators to establish animal models of mycotic keratitis. 66,67 Pretreatment with another immuno-suppressive agent cyclophosphamide is known to induce immuno-suppression within ocular tissues that lead to increased severity and prolonged fungal persistence in a mouse model of fungal corneal ulcer. 68,69 Likewise, the patients with diabetes, chronic granulomatous disease, undergoing ocular surgery, organ transplant, bone marrow transplant, chemotherapy and those of AIDS and HIV infection are more prone to fungal keratitis in case of ocular trauma (Table 2).…”

Section: Injurymentioning

confidence: 99%

Mycotic keratitis: an overview of diagnosis and therapy

Shukla

¹

,

Kumar

²

,

Keshava

³

2008

Mycoses

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The increased incidence of fungal infections in the recent past has been attributed to the increase in the number of human immunodeficiency virus-positive and AIDS patients. Early diagnosis of mycoses in patients is crucial for prompt antifungal therapy. The yield of clinical examination in the diagnosis of keratomycosis is 63-83% and KOH mount is 91%. This still highlights the limitation of routine clinical examination and smear examination, which is not performing 100% efficiently. It is for these 37%, 17% and 9% of cases, every day advanced technologies are called for. Those who deal with patient care are aware of certainties and uncertainties of results of clinical examination. The best reported figures at specialized centres might not translate into clinical practice. Another factor to be kept in mind is that many patients who come after secondary and tertiary referrals are already treated with antibiotics, antivirals, steroids and sometimes even antifungals that distort the clinical picture completely. Further, one has to consider as well the cases caused by yeast-like fungi, which resemble bacterial keratitis. Confirmation of diagnosis, not only in case of mycotic keratitis but also for other diseases, to initiate prompt and accurate therapy would avoid unnecessary and indiscriminate use of steroids/antibacterials/antivirals and antifungals.

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“…(i) Experimental mycotic keratitis. Experimental A. fumigatus keratitis was produced in bred albino New Zealand rabbits by the method of Agrawal et al (1). A spore suspension of A. fumigatus (10 3 CFU/ml) was prepared in physiological saline from a 5-day-old SDA slant culture incubated at 28°C.…”

Section: Methodsmentioning

confidence: 99%

Use of PCR Targeting of Internal Transcribed Spacer Regions and Single-Stranded Conformation Polymorphism Analysis of Sequence Variation in Different Regions of rRNA Genes in Fungi for Rapid Diagnosis of Mycotic Keratitis

Kumar

¹

,

Shukla

²

2005

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The increased incidence of fungal infections in the recent past has been attributed to the increase in the number of human immunodeficiency virus-positive and AIDS patients. Early diagnosis of mycoses in patients is crucial for prompt antifungal therapy. Immunological methods of diagnosis have not been found to be satisfactory, and recent research has been diverted to the use of PCR for the sensitive and early diagnosis at the molecular level. In the present study we targeted different regions of the rRNA gene to diagnose cases of mycotic keratitis and identify the causal agents. Six fungus-specific primers (primers ITS1, ITS2, ITS3, ITS4, invSR1R, and LR12R) were used, and the amplified products were analyzed by single-stranded conformation polymorphism (SSCP) analysis. Dendrograms of these SSCP patterns, prepared on the basis of Jaccard's coefficient, indicated that the PCR products obtained with primer pair ITS1 and ITS2 were the best for the identification of fungi. The results were confirmed by sequencing of the PCR products, and the approach was successfully tested experimentally for the detection of mycotic keratitis caused by Aspergillus fumigatus and was used for the diagnosis of fungal corneal ulcers in patients.Mycotic keratitis or fungal corneal infections have a worldwide distribution, and the incidence is higher in tropical and subtropical countries (8). More than 105 species of fungi belonging to 56 genera have been reported to cause oculomycosis. However, species of Fusarium, Aspergillus, Candida, and other hyaline and dematiaceous hyphomycetes are the usual isolates from patients with mycotic keratitis (20). The management of keratomycosis depends on rapid identification of the causal agent. The diagnosis is often delayed because of the poor availability of infected material from the cornea and the slow growth of a large number of fungi in routinely used culture media, and therefore, early intervention is not always possible and the patient's vision is often lost. In general, the diagnosis of fungal corneal ulcer is dependent on Gram and Giemsa staining, which have low sensitivities of about 50 to 80% (4). Recent advances in molecular biology techniques have opened the door for culture-independent diagnostic methods. Immunological detection (13) and identification by use of distinctive metabolites (2) and nucleic acid probes (7,25) are the tools most often used for diagnosis. One such technique is PCR, which has been shown to be useful for the culture-independent diagnosis of various microbial infections, including mycoses (10,11,22). To date, a few cases of mycotic keratitis have successfully been diagnosed by PCR (5, 6).Ribosomal DNA is the most conserved region in the genome, with capabilities of phylogenetic divergence (14). The whole rRNA gene contains a small subunit (SSU) 18S rRNA, 5.8S rRNA, and a large subunit (LSU) 28S rRNA. Internal transcribed spacer (ITS) region I (ITSI) and ITSII are more variable than the rest of the ribosomal gene subunits and are found between SSU rRNA and 5.8S ...

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“…Prolonged use of topical corticosteroids has generally been described to worsen mycotic keratitis and has been attributed to disturbance in the microbial flora of the eye and local immunosuppression [33,61]. Steroids modulate the proliferative response of T-lymphocytes by acting on interleukin 1 and interleukin 2 production and have been used by several investigators to establish animal models of mycotic keratitis [35][36][37][62][63][64]. In a recent study on animal models, the proliferation of Candida albicans was higher in a group treated with topical dexamethasone when compared to a control group, and neutrophil infiltration decreased significantly in this group [64].…”

Section: Discussion (Concluding Remarks)mentioning

confidence: 99%

Topical Corticosteroids and Fungal Keratitis: A Review of the Literature and Case Series

Knutsson¹,

Iovieno

²

,

Matuška³

et al. 2021

JCM

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The management of fungal keratitis is complex since signs and symptoms are subtle and ocular inflammation is minimal in the preliminary stages of infection. Initial misdiagnosis of the condition and consequent management of inflammation with corticosteroids is a frequent occurrence. Topical steroid use is considered to be a principal factor for development of fungal keratitis. In this review, we assess the studies that have reported outcomes of fungal keratitis in patients receiving steroids prior to diagnosis. We also assess the possible rebound effect present when steroids are abruptly discontinued and the clinical characteristics of three patients in this particular clinical scenario. Previous reports and the three clinical descriptions presented suggest that in fungal keratitis, discontinuing topical steroids can induce worsening of clinical signs. In these cases, we recommend to slowly taper steroids and continue or commence appropriate antifungal therapy.

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Clinical and experimental keratitis due toCurvularia lunata(Wakker) Boedijn var.Aeria(Batista, lima and vasconcelos) Ellis

Cited by 15 publications

References 21 publications

Mycotic keratitis: an overview of diagnosis and therapy

Mycotic keratitis: an overview of diagnosis and therapy

Use of PCR Targeting of Internal Transcribed Spacer Regions and Single-Stranded Conformation Polymorphism Analysis of Sequence Variation in Different Regions of rRNA Genes in Fungi for Rapid Diagnosis of Mycotic Keratitis

Topical Corticosteroids and Fungal Keratitis: A Review of the Literature and Case Series

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