Molecular characterization of drug-resistant and drug-sensitive Aspergillus isolates causing infectious keratitis.

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dc.contributor.authorNayak, Niranjan
dc.contributor.authorSatpathy, Gita
dc.contributor.authorPrasad, Sujata
dc.contributor.authorTitiyal, Jeewan S
dc.contributor.authorPandey, R M
dc.contributor.authorVajpayee, Rasik B
dc.date.accessioned2012-01-02T05:27:22Z
dc.date.available2012-01-02T05:27:22Z
dc.date.issued2011-09
dc.description.abstractPurpose: To study the susceptibilities of Aspergillus species against amphotericin B in infectious keratitis and to find out if drug resistance had any association with the molecular characteristics of the fungi. Materials and Methods: One hundred and sixty Aspergillus isolates from the corneal scrapings of patients with keratitis were tested for susceptibilities to amphotericin B by broth microdilution method. These included Aspergillus flavus (64 isolates), A. fumigatus (43) and A. niger (53). Fungal DNA was extracted by glass bead vertexing technique. Polymerase chain reaction (PCR) assay was standardized and used to amplify the 28S rRNA gene. Single-stranded conformational polymorphism (SSCP) of the PCR product was performed by the standard protocol. Results: Of the 160 isolates, 84 (52.5%) showed low minimum inhibitory concentration (MIC) values (≤ 1.56 μg/ml) and were designated as amphotercin B-sensitive. Similarly, 76 (47.5%) had high MICs (≥ 3.12 μg/ml) and were categorized as amphotericin B-resistant. MIC50 and MIC90 values ranged between 3.12-6.25 μg/ml and 3.12-12.5 μg/ml respectively. A. flavus and A. niger showed higher MIC50 and MIC90 values than A. fumigatus. The SSCP pattern exhibited three extra bands (150 bp, 200 bp and 250 bp each) in addition to the 260 bp amplicon. Strains (lanes 1 and 7) lacking the 150 bp band showed low MIC values (≤ 1.56 μg/ml). Conclusion: A. niger and A. flavus isolates had higher MICs compared to A. fumigatus, suggesting a high index of suspicion for amphotericin B resistance. PCR-SSCP was a good molecular tool to characterize Aspergillus phenotypes in fungal keratitis.en_US
dc.identifier.citationNayak Niranjan, Satpathy Gita, Prasad Sujata, Titiyal Jeewan S, Pandey R M, Vajpayee Rasik B. Molecular characterization of drug-resistant and drug-sensitive Aspergillus isolates causing infectious keratitis. Indian Journal of Ophthalmology. 2011 Sept; 59(5): 373-377.en_US
dc.identifier.urihttps://imsear.searo.who.int/handle/123456789/136208
dc.language.isoenen_US
dc.source.urihttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC3159319/en_US
dc.subjectAntifungal sensitivity testingen_US
dc.subjectamphotericin Ben_US
dc.subjectAspergillusen_US
dc.subjectfungal keratitisen_US
dc.subjectpolymerase chain reaction--single-stranded conformational polymorphism.en_US
dc.subject.meshAntifungal Agents --pharmacology
dc.subject.meshAspergillosis --drug therapy
dc.subject.meshAspergillosis --microbiology
dc.subject.meshAspergillus --drug effects
dc.subject.meshAspergillus --genetics
dc.subject.meshAspergillus --isolation & purification
dc.subject.meshCornea --microbiology
dc.subject.meshDrug Resistance, Fungal
dc.subject.meshEye Infections, Fungal --diagnosis
dc.subject.meshEye Infections, Fungal --microbiology
dc.subject.meshKeratitis --diagnosis
dc.subject.meshKeratitis --microbiology
dc.subject.meshPolymerase Chain Reaction
dc.subject.meshPolymorphism, Single-Stranded Conformational
dc.subject.meshRNA, Fungal --analysis
dc.subject.otherHumans
dc.titleMolecular characterization of drug-resistant and drug-sensitive Aspergillus isolates causing infectious keratitis.en_US
dc.typeArticleen_US
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