Engineering the precursor supply pathway in Streptomyces gilvosporeus for overproduction of natamycin / 生物工程学报

Natamycin is a safe and efficient antimycotics which is widely used in food and medicine industry. The polyene macrolide compound, produced by several bacterial species of the genus Streptomyces, is synthesized by type Ⅰ polyketide synthases using acetyl-CoA, malonyl-CoA, and methylmalonyl-CoA as substrates. In this study, four pathways potentially responsible for the supply of the three precursors were evaluated to identify the effective precursor supply pathway which can support the overproduction of natamycin in Streptomyces gilvosporeus, a natamycin-producing wild-type strain. The results showed that over-expressing acetyl-CoA synthetase and methylmalonyl-CoA mutase increased the yield of natamycin by 44.19% and 20.51%, respectively, compared with the wild type strain under shake flask fermentation. Moreover, the yield of natamycin was increased by 66.29% compared with the wild-type strain by co-overexpression of acetyl-CoA synthetase and methylmalonyl-CoA mutase. The above findings will facilitate natamycin strain improvement as well as development of strains for producing other polyketide compounds.

Advances in the biosynthesis of natamycin and its regulatory mechanisms / 生物工程学报

Natamycin is a polyene macrolide antibiotics with strong and broad spectrum antifungal activity. It not only effectively inhibits the growth and reproduction of fungi, but also prevents the formation of some mycotoxins. Consequently, it has been approved for use as an antifungal food preservative in most countries, and is also widely used in agriculture and healthcare. Streptomyces natalensis and Streptomyces chatanoogensis are the main producers of natamycin. This review summarizes the biosynthesis and regulatory mechanism of natamycin, as well as the strategies for improving natamycin production. Moreover, the future perspectives on natamycin research are discussed.

Post-laser in situ keratomileusis interface Arthrographis kalrae keratitis / Interface de pós-laser ceratomileuse in situ Arthographis Kalrae ceratite

ABSTRACT We describe a case of keratomycosis caused by Arthographis kalrae after excimer laser keratomileusis. A 38-year-old female developed stromal keratitis eight weeks after refractive surgery. She developed severe corneal stromal infiltration and mild anterior segment inflammation, which could not be treated with topical voriconazole 1%, but topical natamycin 5% ameliorated her condition. A reactivation of keratomycosis symptoms was observed; therefore, longer treatment was administered to the patient. It has been reported that A. kalrae keratomycosis is associated with exposure to soil and contact lens usage. However, the patient, who lived in a rural location, was neither involved in gardening activities nor had a history of wearing contact lenses. This is the first case of post-refractive A. kalrae keratomycosis.

RESUMO Descrevemos um caso de ceratomicose por Arthographis kalrae após ceratomileusis por excimer laser. Uma mulher de 38 anos desenvolveu ceratite estromal oito semanas após a cirurgia refrativa. Ela desenvolveu infiltração estromal grave da córnea e uma leve inflamação do segmento anterior, que não pode ser tratada com voriconazol tópico a 1%, mas a natamicina tópica a 5% melhorou sua condição. Uma reativação dos síntomas de ceratomicose foi observada; portanto, tratamento mais prolongado foi administrado a paciente. Tem sido relatado que a ceratomicose por A. kalrae está associada à exposição ao solo e ao uso de lentes de contato. No entanto, a paciente, que vivía em um local rural, não estava envolvida em atividades de jardinagem e nem tinha histórico de uso de lentes de contato. Este é o primeiro caso de ceratomicose pós-refrativa por A. kalrae.

Características clínico-epidemiológicas y evolución del tratamiento en pacientes con úlceras corneales / Clinical-epidemiological characteristics and treatment evolution of patients with corneal ulcer

Las úlceras corneales de origen infeccioso son una emergencia oftalmológica que amenaza la visión y la integridad estructural del ojo, causando ceguera en 1,5 a 2 millones de casos al año por lo que requiere tratamiento inmediato. El objetivo fue determinar el patrón epidemiológico, factores de riesgo y efectividad del tratamiento en pacientes con úlcera corneal en la Fundación Visión en el periodo 2015-2017. Estudio de cohorte prospectivo donde se evaluó 53 pacientes con úlcera corneal de causa infecciosa que consultaron en la Fundación Visión en el periodo 2015-2017, y tuvieron un seguimiento mínimo de 4 meses. Se encontró un predominio del sexo masculino (69,8%), edad 45-65 años (49,1%), casados (54,7%), de condición socioeconómica baja (56,6%), agricultores (26,4%), con antecedente de traumatismo corneal (69,8%) o uso de lentes de contacto (17%). El agente etiológico fue bacteriano en el 49,1% y micótico en el 37,7%; para los de origen bacteriano el tratamiento más empleado fueron colirios fortificados de Cefazolina + Gentamicina y Natamicina/Fluconazol en caso de ser micótico. La evolución fue favorable en 90,9% y 80,0% de los bacterianos y micóticos, respectivamente. Los grupos de riesgo detectados fueron pacientes varones, agricultores, de condición socioeconómica baja, con antecedente de traumatismo corneal o uso de lentes de contacto. La efectividad del tratamiento utilizado fue mayor al 80%, siendo en su mayoría patógenos bacterianos(AU)

Natamicina versus voriconazol para queratitis fúngica / Natamycin versus voriconazole for fungal keratitis

INTRODUCCIÓN: La queratitis infecciosa de origen fúngico afecta principalmente a personas de países tropicales y subtropicales, y constituye una importante causa de ceguera prevenible. Los antifúngicos tópicos, en particular la natamicina y el voriconazol, se consideran efectivos, pero no está claro cuál de ellos constituye la mejor alternativa de tratamiento. MÉTODOS: Realizamos una búsqueda en Epistemonikos, la mayor base de datos de revisiones sistemáticas en salud, la cual es mantenida mediante el cribado de múltiples fuentes de información, incluyendo MEDLINE, EMBASE, Cochrane, entre otras. Extrajimos los datos desde las revisiones identificadas, analizamos los datos de los estudios primarios, realizamos un metanálisis y preparamos una tabla de resumen de los resultados utilizando el método GRADE. RESULTADOS Y CONCLUSIONES: Identificamos tres revisiones sistemáticas que en conjunto incluyeron tres estudios primarios, todos correspondientes a ensayos aleatorizados. Concluimos que natamicina probablemente se asocia a mejor agudeza visual tras la infección, y que previene la perforación corneal y/o la necesidad de realizar queratoplastia terapéutica en comparación a voriconazol en queratitis fúngica.

INTRODUCTION: Infectious keratitis of fungal origin mainly affects people in tropical and subtropical countries, and is an important cause of preventable blindness. Topical antifungals, particularly natamycin and voriconazole, are considered effective, but it is not clear which one is the best treatment alternative. METHODS: We searched in Epistemonikos, the largest database of systematic reviews in health, which is maintained by screening multiple information sources, including MEDLINE, EMBASE, Cochrane, among others. We extracted data from the systematic reviews, reanalyzed data of primary studies, conducted a meta-analysis and generated a summary of findings table using the GRADE approach. RESULTS AND CONCLUSIONS: We identified three systematic reviews including three studies overall,all of which were randomized trials. We concluded natamycin probably is associated with better visual acuity after infection, and it prevents corneal perforation and/or need to perform therapeutic keratoplasty compared to voriconazole in fungal keratitis.

Contact lens-related bilateral and simultaneous Acremonium keratitis / Ceratite bilateral e simultânea por Acremonium relacionada ao uso de lentes de contato

Abstract This is a case of bilateral and simultaneous Acremonium keratitis related to intermittent and alternating eye soft contact lens use, which has a delayed diagnose, presented amphotericin B resistance with persistent hypopyon and had a positive response to topical natamycin. Besides the unusual presentation, there was no history of trauma or contact with vegetable matter, usually associated to the majority of cases of keratomicosys by filamentous fungi.

Resumo Trata-se de um caso de ceratite bilateral e simultânea por Acremonium relacionada ao uso intermitente e sem respeitar a lateralidade do uso de lentes de contato gelatinosas. Houve diagnóstico tardio, apresentando resistência a anfotericina B e hipópio persistente, com resposta positiva a natamicina tópica. Além da forma incomum de apresentação, não houve histórico de trauma ou contato com material vegetal, associado à maioria dos casos de ceratite por fungos filamentosos.

Keratitis Caused by Paecilomyces lilacinus after Cataract Surgery in a Patient with Systemic and Autoimmune Disease

PURPOSE: To report a case of Paecilomyces lilacinus fungal keratitis after cataract surgery in a patient with chronic systemic and autoimmune disease who was treated with medical therapy and penetrating keratoplasty. CASE SUMMARY: A 72-year-old female was referred for decreased visual acuity and ocular pain in the left eye. She underwent cataract surgery in the left eye 1 month earlier and was treated for 2 weeks for corneal edema and stromal infiltration around the corneal suture. She had a chronic systemic disease with hypertension, hyperlipidemia, hepatitis C and rheumatoid arthritis. Suspecting infectious keratitis, the patient was instructed to stop applying topical and systemic steroids and use topical amphotericin B (0.15%) and moxifloxacin (0.5%). However, without improvement, amphotericin B (0.15%) and moxifloxacin (0.5%) were changed to natamycin (5%) and topical voriconazole (2%) and systemic voriconazole was added. However, her systemic status deteriorated and corneal melting developed, scleral graft implantation and amniotic membrane implantation were performed to prevent corneal perforation 6 weeks after the initial visit. Paecilomyces lilacinus was identified in culture at 7 weeks and penetrating keratoplasty was performed 12 weeks after the initial visit. After penetrating keratoplasty, corneal status was stable for 6 months and no signs of recurrence were observed. CONCLUSIONS: In a patient with Paecilomyces lilacinus fungal keratitis and chronic systemic and autoimmune disease, penetrating keratoplasty showed good prognosis when the disease was refractory to topical and systemic antifungal agents.

Improvement of natamycin production in an industrial strain by heterologous expression of the afsRS(cla) global regulatory genes / 生物工程学报

The afsRS(cla) global regulatory genes from Streptomyces clavuligerus activate the production of two antibiotics in Streptomyces lividans. In this study, we gained an increase of 38% in the production of natamycin (3.56 g/L) in an industrial strain Streptomyces gilvosporeus TZ1401 through the integration of pHL851 that bears the afsRS(cla) global regulatory genes into its genome. We discovered by quantitive real-time reverse transcription PCR (qRT-PCR) that the expression of 6 genes of the natamycin biosynthetic gene cluster were improved from 1.9 to 2.7 times. This suggests that afsRS(cla) improve the production of natamycin through increased transcription. This study provides a good example for applying afsRS(cla) in high yield breeding of industrial antibiotic producers.

A Case of Alternaria alternata Keratitis Isolated from Corneal Tissue / 대한의진균학회지

A 71-year-old man presented with pain in the left eye that revealed a 3x3 mm deep corneal stromal infiltrate, with a 2x2 mm epithelial defect. The patient started topical moxifloxacin, voriconazole 2%, and natamycin for 2 weeks. However, the treatment was not effective and the corneal infiltration worsened. Subsequently, the patient underwent therapeutic penetrating keratoplasty. Thick brown/gray mold colonies on Potato Corn Meal Tween 80 agar was isolated from excised corneal tissue and on slide culture many septated, and club-shaped ascospores were revealed. Histological findings also showed numerous hyphae scattered in corneal tissue. A. alternata colonies were confirmed by 18S rRNA sequencing. Intracameral voriconazole was injected every other day for 2 weeks to eliminate remaining fungi on the deep corneal stroma. The remaining corneal infiltration was improved one month after the injection. During 5 months postoperative follow up, the infection did not recurred. In conclusion, deep corneal infection of A. alternata was effectively treated with intracameral voriconazole injection.

A Case of Beauveria Bassiana Keratitis Confirmed by Gene Sequencing

PURPOSE: To report a case of Beauveria bassiana keratitis that was confirmed by gene sequencing. CASE SUMMARY: A 70-year-old man presented to our hospital with complaints of ocular pain and deterioration of the visual acuity in his left eye after injury caused by a wood branch one week previously. Visual acuity in the left eye was 20/400 at the time of the first visit. Slit lamp examination showed a central 0.7 x 2.5-mm-sized epithelial defect surrounded by cellular infiltration in the stroma. Scraping of the corneal lesion for microbiological examinations was performed. Initial Gram stain, potassium hydroxide (KOH) mount, and culture were negative. However, fungal hyphae were observed on a KOH mount of the repeated corneal scraping specimen, and a Beauveria species was suspected based on the culture. Beauveria bassiana was confirmed using a MicroSEQ(R) D2 large-subunit ribosomal DNA fungal sequencing kit. Natamycin eye solution was initially instilled bihourly (every two hours), but the persistent epithelial defect and progressive stromal melting finally resulted in a descemetocele. Temporary and permanent amniotic membrane transplantations were performed, and amphotericin B eye solution was administered bihourly (every two hours). The ulcerous lesion gradually improved with no evidence of recurrence. CONCLUSIONS: Recently, cases of fungal keratitis have been increasing. Therefore, molecular diagnosis methods such as gene sequencing can be helpful in diagnosis and in improving the prognosis of fungal keratitis caused by rare fungi, as we found in this case.

A Case of Phoma glomerata Keratitis Occurred in Recurrent Herpes Simplex Keratitis Cicatrix

PURPOSE: To report a case of Phoma glomerata keratitis occurring in recurrent herpes simplex keratitis cicatrix. CASE SUMMARY: A 63-year-old male patient was admitted to our hospital with complaints of abrupt visual deterioration and ocular pain in his left eye. He was treated for recurrent herpes simplex keratitis in the same eye 12 years prior. Because central desmatocele was observed as a result of advanced corneal stromal melting, Gram staining, Potassium Hydroxide (KOH) mount, and culture were performed in corneal scrape specimens. On microbiological evaluation, a Phoma species was detected and Phoma glomerata was diagnosed using DNA sequencing method. Two consecutive amniotic membrane transplantations were performed with topical antifungal agents. The lesion was not improved when using topical amphotericin B and natamycin eyedrops, thus fluconazole eyedrops were used additionally. The corneal infection was resolved with central thick opacification. CONCLUSIONS: In the present case, herpetic keratitis was the main underlying causative factor because the patient had no past history of trauma. When diverse appearances of keratitis occur in herpes simplex keratitis patients, clinicians need to consider the concurrence of fungal infection, especially Phoma glomerata, a rare fungal organism.

Simultaneous determination of sodium benzoate, potassium sorbate and natamycin content in Iranian yoghurt drink [Doogh] and the associated risk of their intake through doogh consumption

Regarding the public health concerns over the use of food preservatives in yoghurt drink "Doogh", the aim of this study was the determination of sodium benzoate, potassium sorbate and natamycin in Doogh. Based on Iranian national standard, none of these preservatives are permitted to be used in Doogh. A total of 39 Doogh samples were analyzed through RP- HPLC in order to quantify sodium benzoate, potassium sorbate and natamaycin simultaneously. Exposure to each preservative is estimated by mean and maximum concentrations as the residue levels. The per capita Doogh consumption was calculated by the published data from official reports for Doogh annual production in Iran. All samples were shown to contain sodium benzoate while natamaycin was detected in 10.25% of the samples and potassium sorbate was not detected in any of them. Sodium benzoate concentration extremely varied among the investigated samples ranged from 0.94 to 9.77 mg/l. Due to the result of the exposure estimation, no serious public health concern would exist regarding the mentioned preservatives. The detection of sodium benzoate in all Doogh samples could indicate the natural production of benzoic acid in yoghurt. Sodium benzoate may be formed through the interaction of the added food grade salt to the Doogh formula which contains benzoic acid. The results of exposure estimation show the lack of health risk within the usage of preservatives in spite of the national agencies does not permit the preservative use

Keratomycosis caused by Exserohilum rostratum.

We report a case of keratomycosis caused by Exserohilum rostratum. A 46-year-old farmer presented with history of pain, watery discharge and redness of the right eye for the past 2 weeks following trauma with vegetable matter. On ocular examination, a central corneal ulcer of about 8 mm with a greyish-white slough, feathery edges and diffuse corneal edema was seen in the right eye. KOH examination of corneal scrapings revealed thick, brown, branched, septate hyphae. Culture of corneal scrapings on Sabouraud dextrose agar showed velvety greenish-black colony with a black pigment on the reverse. The culture was identified as E. rostratum on the basis of microscopic morphology. The patient responded well to treatment with topical natamycin and oral itraconazole.

Natamycin in the treatment of keratomycosis: Correlation of treatment outcome and in vitro susceptibility of fungal isolates.

In this study, 60 fungal isolates from 60 patients with fungal keratitis were tested in vitro for their susceptibility to natamycin and the mean minimum inhibitory concentrations of natamycin (MICn) were correlated with clinical outcome. The mean MICn for various groups of fungi from patients with either early (<10 days) or late (≥10 days) presentation was correlated with the outcome. Aspergillus flavus showed resistance to natamycin with a high mean MICn (>16 μg/ml). While the clinical response in all patients with early A. flavus keratitis was good it was poor in late cases (5/8 patients, 62.5%). Fusarium species, Acremonium species and dematiaceous fungi were sensitive with low mean MICn (Fusarium: 5.7-7.2 μg/ml, Acremonium: 5.7-6.8 μg/ml, dematiaceous: (1.6-4 μg/ml). However, 46.6% (7/15) patients in Fusarium and 57.1% (4/7) in Acremonium group needed keratoplasty. We conclude that despite susceptibility of most fungal species causing keratitis to natamycin, the treatment outcome is poor in advanced fungal keratitis.

A Case of Fungal Keratitis Caused by Drechslera Species

PURPOSE: To report a case of fungal keratitis caused by Drechslera species. CASE SUMMARY: A 77-year-old man visited our clinic complaining of left ocular pain and decrease of visual acuity for 1 week On slit-lamp examination, epithelial defect and stromal infiltration on the corneal center with numerous inflammatory cells in the anterior chamber were found. There was no improvement after routine antibiotic treatment. A corneal biopsy and culture were performed on the corneal lesion. The KOH smear study reported hyphae, thus the patient was treated with 0.25% amphotericin B, 0.2% fluconazole and 5% natamycin eye drops. A clinical improvement was observed on the corneal lesion and Drechslera species was identified by the culture study. CONCLUSIONS: The authors report an experience of fungal keratitis caused by Drechslera species.

Colletotrichum graminicola keratitis: First case report from India.

Colletotrichum graminicola is a medically important fungus belonging to the order Melanconiales under the class Coelomycetes. The members of the genus Colletotrichum are primarily plant pathogens which cause anthracnoses (fungal infection in plants). In the past few decades, they are progressively being implicated as etiological agents of subcutaneous hyalohyphomycoses and keratomycoses. Of the five medically important members in the genus Colletotrichum, keratitis due to Colletotrichum graminicola is rare. We diagnosed Colletotrichum graminicola keratitis in a 44-year-old man who presented with a non-healing corneal ulcer since three weeks. Positive smears and cultures from the corneal scrapings established the causative organism as C. graminicola. The patient was treated with a combination of oral ketoconazole and topical fluconazole and natamycin. Infection resolved over 10 weeks and antimicrobials were stopped. We describe the clinical presentation and treatment outcome of Colletotrichum graminicola keratitis.

effect of natamycin on keeping quality and organoleptic characters of yoghurt

This study was planned to evaluate the shelf life and the changes occurring in the organoleptic characters of yoghurt supplemented with natamycin during the storage period. Yoghurt samples were prepared and divided into two groups; natamycin was added to the first group at the levels of 10 and 20 mg / kg, while the second group of yoghurt was prepared without natamycin and kept as a control. Yoghurt cups were stored all over the experimental period [35 days] at 4 +/- 1°C. Organoleptic examinations, estimation of pH and titertable acidity as well as enumeration of total moulds and yeasts were done on both treated and control yoghurts. The yoghurts were examined at the 3[rd] and 7[th] days, then weekly till the end of storage period. The treated group of yoghurt showed acceptable degree of organoleptic examination, while yeasts and moulds were not detected till the end of the storage time. On the other hand, control samples of yoghurt showed unacceptable degrees of examination and contamination with moulds and yeasts. Natamycin was proved to be a suitable and effective antifungal agent which increases the shelf life of yoghurt without changing in the normal characters of the products

Extraction and structural identification of the antifungal metabolite of Streptomyces lydicus A02 / 生物工程学报

We isolated a high efficient antifungal strain A02 from forest soil in a suburb of Beijing. The result of polyphasic taxonomy confirmed that strain A02 belongs to Streptomyces lydicus. The fermented broth of the strain presented a stable and strong inhibiting activity against many plant pathogenic fungi. The purpose of this study was to ascertain the substance base of the antifungal activity of strain A02. We extracted the antifungal metabolite of A02 by using column chromatography with X-5 macroporous resin and 100-200 mesh silica gel respectively, and then purified it by LC-9101 recycling preparative HPLC with a SP-120-15 column (JAIGEL-ODS-AP). An active compound with purity over 99.845% was finally obtained. The chemical structure of the active compound was determined with spectroscopy methods, including ultraviolet spectrometry, infrared spectrometry, high resolution mass spectrometry and nuclear magnetic resonance. According to the analysis results, we identified the active compound as a tetraene macrolide antibiotic with the molecular weight of 665, the molecular formula C33H47No3 and the same chemical structure as natamycin. Our research revealed a new biosynthetic function for S. lydicus to produce natamycin, and an expanding application field for natamycin to be used for the control of fungal plant diseases.

Effect of topical application of terbinafine on fungal keratitis / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Fungal keratitis is a rare but serious corneal disease that may result in loss of vision. The poor prognosis might be due to limited treatment option. This study aimed to evaluate the clinical efficacy of 0.25% terbinafine eye drops comparing with 5% natamycin suspension on fungal keratitis.</p><p><b>METHODS</b>A retrospective clinical trial was performed on 90 patients presenting with direct smear and/or culture positive fungal keratitis at Beijing Tongren Hospital, Beijing, China from January 2006 to May 2008. Corneal ulcers were categorized as mild or severe. Forty-five patients were treated with topical terbinafine and the next 45 cases received topical natamycin hourly.</p><p><b>RESULTS</b>Filamentous fungi were found in corneal scrapings among all 90 cases. Fungal cultures were positive in 64 patients (71%). Species of Fusarium and Aspergillus were the principal isolates. Forty (89%) patients showed favorable response to terbinafine, while forty-two (93%) patients exhibited favorable response to natamycin (P > 0.05). The mean course of treatment was significantly showed in the terbinafine treatment group than natamycin group ((26.5 +/- 11.2) days versus (19.3 +/- 6.4) days; P < 0.05). In terbinafine group, twenty patients with ulcers smaller than 4 mm had favorable outcome, while 20 of 25 patients with ulcers more than 4 mm in diameter had favorable response (P < 0.05). Twenty-seven patients with depth of infiltration less than half of stroma thickness had favorable response to terbinafine, while 13 of 18 patients with depth of infiltration more than half of stroma responded to terbinafine. This difference was statistically significant (P < 0.05).</p><p><b>CONCLUSIONS</b>Our findings suggest that topical terbinafine is an effective antifungal drug for the management of filamentous mycotic keratitis, particularly in cases with smaller and shallower ulcers. Its mean duration of treatment was longer than natamycin.</p>

Effect of topical 0.5 percent povidone-iodine compared to 5 percent natamycin in fungal keratitis caused by Fusarium solani in a rabbit model: a pilot study / Efeito tópico de iodo-povidona 0, 5 por cento comparado com natamicina 5 por cento em ceratites fúngicas causadas por Fusarium solani em um modelo animal de coelhos: estudo piloto

PURPOSE: To evaluate the efficacy of topical administration of 0.5 percent povidone-iodine in experimental Fusarium solani keratitis in rabbits. METHODS: Fungal keratitis caused by Fusarium solani was induced in the right eye of 24 New Zealand rabbits. The rabbits were randomly divided into 3 different treatment groups: Group I (povidone-iodine) - treated with topical 0.5 percent povidone-iodine; Group II (natamycin) - treated with topical 5 percent natamycin; and Group III (control) - treated with topical saline solution. In all groups the rabbits were treated for three days and then sacrificed. The corneas were excised, macerated and immersed in 10 mL BHI. Culture samples were plated daily on Sabouraud's agar for 7 days, and the number of colony-forming units (CFU) was counted. The rabbits were clinically evaluated during the treatment period. RESULTS: The povidone-iodine and natamycin groups demonstrated better efficacy than the control group based on the number of rabbits with no colonies growing. However, there were no statistically significant differences between the three groups when the number of CFU was analyzed (p>0.05). CONCLUSIONS: Our study demonstrates important methodological considerations in the use of in vivo animal models for the testing of antifungal agents. Using this sample size and methodology of counting CFU, topical 0.5 percent povidone-iodine demonstrated no benefit in the treatment of experimental Fusarium solani when compared with topical 5 percent natamycin.

OBJETIVO: Avaliar a eficácia do uso tópico de iodo-povidona 0,5 por cento em ceratite experimental por Fusarium solani em coelhos. MÉTODOS: Ceratite fúngica por Fusarium solani foi induzida no olho direito de 24 coelhos da raça New Zealand. Os coelhos foram divididos aleatoriamente em 3 diferentes grupos de tratamento: Grupo I (iodo-povidona) - tratados com iodo-povidona 0,5 por cento; Grupo II (natamicina) - tratados com natamicina 5 por cento; Grupo III (controle) - tratados com solução salina. Os coelhos dos 3 grupos foram tratados por 3 dias e sacrificados em seguida. As córneas foram removidas cirurgicamente, maceradas e incubadas em meio BHI. Semeou-se culturas em placas de ágar Sabouraud, diariamente, durante 7 dias, e contou-se o número de unidades formadoras de colônias (UFC). Os coelhos foram avaliados clinicamente durante o período de tratamento. RESULTADOS: Os grupos iodo-povidona e natamicina demonstraram melhor eficácia do que o grupo controle considerando-se o número de coelhos nos quais não houve crescimento de colônias. Entretanto, não houve diferença estatística significante entre os 3 grupos quando se analizou o número de UFC (p>0,05). CONCLUSÃO: Este estudo demonstrou considerações metodológicas importantes na utilização de modelos animais para o teste de agentes antifúngicos. Usando a metodologia de contar UFC e com este tamanho amostral, administração tópica de iodo-povidona 0,5 por cento não demonstrou benefício do tratamento de ceratite fúngica experimental causada por Fusarium solani quando comparado com a administração tópica de natamicina 5 por cento.