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Oladosu I.A.,University of Ibadan | Ogundajo A.L.,University of Ibadan | Ogundajo A.L.,Lagos State University | Aiyelaagbe D.O.,University of Ibadan | Emenyonu N.,Tuberculosis Research Laboratory
Research Journal of Phytochemistry | Year: 2011

The present study seeks to evaluate the medicinal relevance of the Coffea brivipes extracts against some clinically identified strains of Mycobacterium tuberculosis, using standard methods of microbial sensitivity test and phytochemical analysis. The whole plant samples of Coffea brivipes were extracted with absolute ethanol. The ethanol extract of Coffea brivipes HIERN (RUBIACEA) was then macerated with hexane, chloroform and ethyl acetate successively to obtain hexane, chloroform and EtOAc soluble extracts. The extracts were screened for their phytochemical composition and anti-bacterial activities. The phytochemical results depicted the presence of carbohydrate, alkaloids, tanins, sterols, flavonoids, resins and phenols distributed in varying degrees. The antibacterial activity of the extracts against Mycobacterium tuberculosis (MTB 050 and 303) were carried out using the egg enriched Lowenstein-Jansen medium with isoniazid, dihydrostreptomycin, enthanbutol and rifampicin as standard control drugs. The extracts showed different anti-bacterial activities at 10 -2 and 10 -4 bacteria load. MTB 050 strains showed resistance to rifampicin at both innoculum. Hexane and ethylacetate extracts of C. brivipes at 5 mg mL -1 exhibited good anti-bacterial activities against this rifampicin resistance strain. The result suggest that the hexane and ethylacetate extracts of Coffea brivipes can serve as a good cut for the replacement of rifampicin as an anti-Tb drug. © 2011 Academic Journals Inc. Source

Jung J.-J.,University of South Carolina | Madan-Lala R.,Emory University | Georgieva M.,Emory University | Rengarajan J.,Emory University | And 3 more authors.
Infection and Immunity | Year: 2013

Nitric oxide (NO) is a diffusible radical gas produced from the activity of nitric oxide synthase (NOS). NOS activity in murine macrophages has a protective role against mycobacteria through generation of reactive nitrogen intermediates (RNIs). However, the production of NO by human macrophages has remained unclear due to the lack of sensitive reagents to detect NO directly. The purpose of this study was to investigate NO production and the consequence to mycobacteria in primary human macrophages. We found that Mycobacterium bovis BCG or Mycobacterium tuberculosis infection of human macrophages induced expression of NOS2 and NOS3 that resulted in detectable production of NO. Treatment with gamma interferon (IFN-γ), L-arginine, and tetrahydrobiopterin enhanced expression of NOS2 and NOS3 isoforms, as well as NO production. Both of these enzymes were shown to contribute to NO production. The maximal level of NO produced by human macrophages was not bactericidal or bacteriostatic to M. tuberculosis or BCG. The number of viable mycobacteria was increased in macrophages that produced NO, and this requires expression of nitrate reductase. An narG mutant of M. tuberculosis persisted but was unable to grow in human macrophages. Taken together, these data (i) enhance our understanding of primary human macrophage potential to produce NO, (ii) demonstrate that the level of RNIs produced in response to IFN-γ in vitro is not sufficient to limit intracellular mycobacterial growth, and (iii) suggest that mycobacteria may use RNIs to enhance their survival in human macrophages. © 2013, American Society for Microbiology. Source

Albert H.,Tuberculosis Research Laboratory | Manabe Y.,Infectious Diseases Institute IDI | Lukyamuzi G.,Tuberculosis Research Laboratory | Ademun P.,Tuberculosis Research Laboratory | And 5 more authors.
PLoS ONE | Year: 2010

Background: Direct smear microscopy using Ziehl-Neelsen (ZN) staining is the mainstay of tuberculosis (TB) diagnosis in most high burden countries, but is limited by low sensitivity in routine practice, particularly in high human immunodeficiency virus (HIV) prevalence settings. Methods: We compared the performance of three commercial light emitting diode (LED)-based microscopy systems (Primostar™ iLED, Lumin™ and AFTER®) for fluorescent detection of Mycobacterium tuberculosis with ZN microscopy on slides prepared from sputum of TB suspects. Examination time for LED-based fluorescent microscopy (LED FM) and ZN slides was also compared, and a qualitative user appraisal of the LED FM systems was carried out. Results: LED FM was between 5.6 and 9.4% more sensitive than ZN microscopy, although the difference was not statistically significant. There was no significant difference in the sensitivity or specificity of the three LED FM systems, although the specificity of Fraen AFTER was somewhat lower than the other LED FM methods. Examination time for LED FM was 2 and 4 times less than for ZN microscopy. LED FM was highly acceptable to Ugandan technologists, although differences in operational performance of the three systems were reported. Conclusions: LED FM compares favourably with ZN microscopy, with equivalent specificity and a modest increase in sensitivity. Screening of slides was substantially quicker using LED FM than ZN, and LED FM was rated highly by laboratory technologists. Available commercial systems have different operational characteristics which should be considered prior to programmatic implementation. © 2010 Albert et al. Source

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