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.
Antifungal Agents/pharmacology* ; Fungi ; Natamycin ; Streptomyces

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.
Aged ; Amphotericin B ; Anterior Chamber ; Biopsy ; Fluconazole ; Humans ; Hyphae ; Keratitis ; Natamycin ; Ophthalmic Solutions ; Visual Acuity

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.
Anti-Bacterial Agents ; biosynthesis ; Genes, Regulator ; Industrial Microbiology ; Multigene Family ; Natamycin ; biosynthesis ; Streptomyces ; genetics

PURPOSE: To present a case report of fungal keratitis related to prolonged overnight use of orthokeratology contact lenses. METHODS: A 13 year-old girl presented with a corneal ulcer in her left eye refractory to antibacterial medication. She had a history of wearing orthokeratology contact lenses overnight for seven months. RESULTS: The organism Aspergillus was isolated by corneal scraping, the contact lens itself, and from the storage case. The patient was treated with topical fluconazole and Natamycin pimaricin in addition to oral itraconazole, resulting in a resolution of the ocular lesion. CONCLUSIONS: The risk of fungal infection as a potential complication of the use of overnight orthkeratology contact lenses should be considered when using these lenses.
Adolescent ; Aspergillus ; Contact Lenses ; Corneal Ulcer ; Female ; Fluconazole ; Humans ; Itraconazole ; Keratitis* ; Natamycin

Fungal corneal ulcer could lead to a devastating outcome. The relative scarcity of readily available, inexpensive but effective topical antifungal drug has left many ophthalmologists desperate and frustated in treating the condition. The use of oral itraconazole has long been proven to be of clinical value in a number of forms of mycoses. Its safety profile is extremely good with minimal reported adverse effects. We investigated an aqueous form of itraconazole which we prepared into a 0.1 mg/ml concnetration and compared its efficacy as a topical antifungal against the standard drug. Natamycin 5 percent in the treatment of fungal keratitis in rabbits. A randomized animal trial was done using 24 rabbit eyes divided into 2 treatment groups. All rabbit corneas were inoculated with Aspergillus flavus and treated after 48 hours with either Topical itraconazole or Natamycin 5 percent for a period of 2 weeks. Results showed inhibition of the disease with both treatment groups. We also found no significant difference between the severity, progression and remission of the keratitis between both treatment groups clinically and statistically. Topical itraconazole 0.1 mg/ml was shown to be comparable to our standard topical antifungal Natamycin 5 percent in treating fungal keratitis. (Author)
Animal ; ASPERGILLUS KERATITIS ; OPHTHALMOLOGY ; ASPERGILLUS FLAVUS ; NATAMYCIN ; ITRACONAZOLE ; FUNGAL CORNEAL ULCER ; FUNGAL KERATITIS

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.
Antifungal Agents ; chemistry ; isolation & purification ; Natamycin ; analogs & derivatives ; Soil Microbiology ; Streptomyces ; chemistry ; isolation & purification ; metabolism

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.
Natamycin/metabolism* ; Methylmalonyl-CoA Mutase/metabolism* ; Acetyl Coenzyme A/metabolism* ; Streptomyces/genetics* ; Polyketide Synthases/metabolism*

PURPOSE: To present a case report of fungal keratitis related to prolonged overnight use of orthokeratology contact lenses. METHODS: A 13 year-old girl presented with a corneal ulcer in her left eye refractory to antibacterial medication. She had a history of wearing orthokeratology contact lenses overnight for seven months. RESULTS: The organism Aspergillus was isolated by corneal scraping, the contact lens itself, and from the storage case. The patient was treated with topical fluconazole and Natamycin pimaricin in addition to oral itraconazole, resulting in a resolution of the ocular lesion. CONCLUSIONS: The risk of fungal infection as a potential complication of the use of overnight orthkeratology contact lenses should be considered when using these lenses.
Aspergillus ; Contact Lenses ; Corneal Dystrophies, Hereditary ; Corneal Ulcer ; Eye ; Fluconazole ; Humans ; Itraconazole ; Keratitis ; Keratomileusis, Laser In Situ ; Natamycin

PURPOSE: To report drug-resistant fungal keratitis that was treated with voriconazole. CASE SUMMARY: A 31-year-old man was admitted to hospital because of ocular pain, conjunctival injection, and visual weakness 7 days after LASIK surgery. At that time, his vision was counting finger at 30 cm and he presented with corneal epithelial defects, stromal infiltration, and inflammation in the anterior chamber of his eye. He was transferred to our hospital because his infection was resistant to gatifloxacin, tobramycin, amphotericin B, and natamycin eyedrops. At the time of transfer, his vision was counting finger at 30 cm and he presented with corneal epithelial defects, stromal infiltration, and hypopyon. He was treated with topical 2% voriconazole every 2 hours and the lesion improved. However, the hypopyon recurred after 12 days. He was then treated with intracameral voriconazole injection (50 microgram/0.1 cc) and topical 5% voriconazole every hour causing the hypopyon to disappear. His vision improved from counting finger to 20/40 six months after this treatment.
Adult ; Amphotericin B ; Anterior Chamber ; Eye ; Fingers ; Fluoroquinolones ; Humans ; Inflammation ; Keratectomy, Subepithelial, Laser-Assisted ; Keratitis ; Keratomileusis, Laser In Situ ; Natamycin ; Ophthalmic Solutions ; Pyrimidines ; Tobramycin ; Triazoles ; Vision, Ocular

Colletotrichum is mainly a fungal pathogen of plants, but sporadic cases of human infection have been reported recently. Most of them are fungal keratitis and only a few cases have been reported worldwide. A 63-year-old female farmer developed foreign body sensation and watering in her left eye following trauma by rice leaves. At presentation, her visual acuity decreased and corneal ulcer and inflammation in anterior chamber were observed on a slit lamp examination. Numerous hyphae were found on Gram stain and a rapidly growing mold with cup-shaped acervuli and falcate and nonseptate conidia was observed on fungal culture. As morphological findings did not lead to definite differentiation of the organism, sequencing of the D1-D2 domain of 28S rDNA was performed. It proved to be Colletotrichum species and the patient was treated with amphotericin and natamycin eye drop, but complicated by acute glaucoma. This is the first report of Colletotrichum keratitis in Korea and suggests that its infection should be considered in patients with fungal keratitis.
Amphotericin B ; Anterior Chamber ; Colletotrichum* ; Corneal Ulcer ; DNA, Ribosomal ; Female ; Foreign Bodies ; Fungi ; Glaucoma ; Humans ; Hyphae ; Inflammation ; Keratitis* ; Korea ; Middle Aged ; Natamycin ; Sensation ; Spores, Fungal ; Visual Acuity ; Water