Yendremban Randhir Babu Singh

Dr. G. R. Damodaran College of Science, Coimbatore, Koyambattūr, Tamil Nādu, India

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Publications (5)2.21 Total impact

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    ABSTRACT: The in vitro antifungal activities of azole drugs viz., itraconazole, voriconazole, ketoconazole, econazole and clotrimazole were investigated in order to evaluate their efficacy against filamentous fungi isolated from mycotic keratitis. The specimen collection was carried out from fungal keratitis patients attending Aravind eye hospital and Post-graduate institute of ophthalmology, Coimbatore, India and was subsequently processed for the isolation of fungi. The dilutions of antifungal drugs were prepared in RPMI 1640 medium. Minimum inhibitory concentrations (MICs) were determined and MIC50 and MIC90 were calculated for each drug tested. A total of 60 fungal isolates were identified as Fusarium spp. (n=30), non-sporulating moulds (n=9), Aspergillus flavus (n=6), Bipolaris spp. (n=6), Exserohilum spp. (n=4), Curvularia spp. (n=3), Alternaria spp. (n=1) and Exophiala spp. (n=1). The MICs of ketoconazole, clotrimazole, voriconazole, econazole and itraconazole for all the fungal isolates ranged between 16μg/mL and 0.03μg/mL, 4μg/mL and 0.015μg/mL, 8μg/mL and 0.015μg/mL, 8μg/mL and 0.015μg/mL and 32μg/mL and 0.06μg/mL respectively. From the MIC50 and MIC90 values, it could be deciphered that in the present study, clotrimazole was more active against the test isolates at lower concentrations (0.12-5μg/mL) when compared to other drugs tested. The results suggest that amongst the tested azole drugs, clotrimazole followed by voriconazole and econazole had lower MICs against moulds isolated from mycotic keratitis. Copyright © 2014 Elsevier Masson SAS. All rights reserved.
    Journal de Mycologie Médicale/Journal of Medical Mycology 12/2014; 25(1). DOI:10.1016/j.mycmed.2014.10.024 · 0.40 Impact Factor
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    ABSTRACT: Fusarium spp. are the most frequently isolated causative agents of keratitis in South India. Due to the great number of antifungal resistant Fusaria, new, alternative therapeutic agents are extremely needed. Essential oils and their compounds are considered as potential antifungal agents. The aim of this study was to investigate the antifungal effect of 9 essential oils (Cinnamomum zeylanicum, Citrus limon, Eucalyptus citriodora, Gaultheria procumbens, Juniperus communis, Melaleuca alternifolia, Origanum majoranna, Salvia sclarea and Thymus vulgaris oil) and their combination with antifungals in broth microdilution test against the most common etiologic agents of Fusarium keratitis in South India. The metabolic inhibition effect of the most active oil and its component was investigated by FUN-1 staining. The lowest minimal inhibitory concentration values were observed in the case of C. zeylanicum oil (CZO) and its main component, trans-cinnamaldehyde (tCA). Whereas, the C. limon oil was the least effective. Interaction tests revealed mostly no interaction between tCA and natamycin. FUN-1 staining revealed that CZO and tCA cause reduced cellular metabolism. According to our results CZO and tCA could be potentially used in the treatment of Fusarium keratitis. The research of M.H., Cs.V. and L.G. was supported by the European Union and the State of Hungary, co-financed by the European Social Fund in the framework of TÁMOP 4.2.4.A/2-11-1-2012-0001 'National Excellence Program'. The relating research groups were also supported by the INSA-HAS interacademic bilateral project (SNK-49/2013) providing infrastructure and research equipment.
    Ecoforum 2014; 09/2014
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    24th European Congress of Clinical Microbiology and Infectious Diseases (ECCMID); 05/2014
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    ABSTRACT: Background: Coagulase negative Staphylococci (CoNS) are common inhabitants of human skin and mucous membranes. With the emergence of these organisms as prominent pathogens in patients with ocular infections, investigation has intensified in an effort to identify important virulence factors and to inform new approaches to treatment and prevention. Aim: To isolate CoNS from ocular specimens; to study the possible virulence factors; speciation of coagulase negative staphylococci (CoNS) which were isolated from ocular complications; antibiotic susceptibility testing of ocular CoNS. Materials and Methods: The specimens were collected from the target patients who attended the Microbiology Laboratory of a tertiary care eye hospital in Coimbatore, Tamilnadu state, India. The isolates were subjected to tube and slide coagulase tests for the identification of CoNS. All the isolates were subjected to screening for lipase and protease activities. Screening for other virulence factors viz., slime production on Congo red agar medium and haemagglutination assay with use of 96-well microtitre plates. These isolates were identified upto species level by performing biochemical tests such as phosphatase test, arginine test, maltose and trehalose fermentation tests and novobiocin sensitivity test. The isolates were subjected to antibiotic susceptibility studies, based on the revised standards of Clinical and Laboratory Standards Institutes (CLSI). Results: During the one year of study, among the total 260 individuals who were screened, 100 isolates of CoNS were obtained. Lipolytic activity was seen in all the isolates, whereas 38 isolates showed a positive result for protease. A total of 63 isolates showed slime production. Of 100 isolates, 30 isolates were analyzed for haemagglutination, where 4 isolates showed the capacity to agglutinate the erythrocytes. The results of the biochemical analysis revealed that of the 100 isolates of CoNS, 43% were Staphylococcus epidermidis. The other isolates were identified as S. xylosus (n=8), S. captis (n=16), S. haemolyticus (n=10), S. saccharolyticus (n=2), S. hominis (n=5), S. saprophyticus (n=6) and S. intermedius (n=1). On the other hand, 9 isolates were not identified. In the antibiotic susceptibility analysis, it was found that most of the isolates were sensitive to vancomycin, amikacin and linczolid and resistant to cefatoxime, oxacillin, bacitracin and nalidixic acid. Conclusion: S. epidermidis was found to be predominant in causing the ocular complications. Slime production, heamagglutination, protease and lipase activities could be the putative virulence factors of CoNS. Antibiotic susceptibility patterns of CoNS against antibacterial agents revealed maximum resistance to beta lactam groups, and the resistance was found to be higher to oxacillin, and lowest to vancomycin.
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    ABSTRACT: Full text: http://onlinelibrary.wiley.com/doi/10.1111/j.1439-0507.2012.02194.x/pdf In recent years, Aspergillus species are reported frequently as aetiological agents of fungal keratitis in tropical countries such as India. Our aim was to evaluate the epidemiological features of Aspergillus keratitis cases over a 3-year period in a tertiary eye care hospital and to determine the antifungal susceptibilities of the causative agents. This study included culture proven Aspergillus keratitis cases diagnosed between September 2005 and August 2008. Data including prevalence, predisposing factors and demography were recorded, the isolates were identified by morphological and molecular methods and the minimum inhibitory concentration values of antifungal agents towards the isolates were determined by the microdilution method. Two hundred Aspergillus isolates were identified among 1737 culture proven cases. Most of the aspergilli (75%) proved to be A. flavus, followed by A. fumigatus (11.5%). Sixteen (8%) isolates belonged to species that are recently identified causative agents of mycotic keratitis. Most of the infected patients (88%) were adults ranging from 21 to 70 years of age. Co-existing ocular disease was confirmed in 16.5% of the patients. Econazole, clotrimazole and ketoconazole were notably active against A. flavus. Aspergillus keratitis is a significant problem in patients with ocular lesions in South-Indian States, warranting early diagnosis and initiation of specific antifungal therapy to improve outcome.
    Mycoses 04/2013; 56(1):26-33. DOI:10.1111/j.1439-0507.2012.02194.x · 1.81 Impact Factor

Publication Stats

10 Citations
2.21 Total Impact Points

Institutions

  • 2014
    • Dr. G. R. Damodaran College of Science, Coimbatore
      Koyambattūr, Tamil Nādu, India
    • Regional Institute of Medical Sciences
      • Department of Microbiology
      Imphal, Manipur, India
    • Dr G R Damodaran college of Science
      Koyambattūr, Tamil Nadu, India
  • 2013
    • Aravind Eye Hospital
      Mathurai, Tamil Nadu, India