Staphylococcus

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About Medically important Staphylococcus

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By: varuncn (61 month(s) ago)

Ok. Enabled

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Staphylococcus:

Staphylococcus Varun C N www.microboids.net

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M. luteus S. aureus S. epidermidis S. saprophyticus 2 Staphylococcus Catalase positive Aerobic Facultative Anaerobe

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Gram positive coccus Cluster arrangement Facultative anaerobes Catalase +, Modified Oxidase - Medically important members S. aureus S. epidermidis S. saprophyticus 3 Staphylococcus

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Staphylococcus 4 Staphylococcus aureus Mesophilic Facultative anaerobe Circular, convex, smooth and buttery colonies Usually produce β - Hemolysis on blood agar Resistant to chemicals like Lithium chloride, Tellurite, NaCl Resistant to Lysozyme but sensitive to anniline dyes, Unsaturated fatty acids, Lysotaphin Biochemical characters Ferment Mannose Produces Catalase, Urease, Gelatinase, Phosphatase Reduce Nitrate MR and VP positive

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Staphylococcus 5

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Staphylococcus 6 Staphyloxanthin Carotenoid pigment Antioxidant action Non diffusing pigment Pigment production can be enhanced by culturing at 22 C in presence of 1% Glycerol monoacetate aerobically.

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Staphylococcus 7

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8 Staphylococcus

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Staphylococcus 9 Staphylococcal protein A (SpA) Type I membrane protein It is a surface protein covalently bound to the peptidoglycan layer Inhibits antibody mediated clearance by binding with IgG1, IgG2 and IgG4 Fc receptors Z domain contains three alpha helices which are arranged in an antiparallel three-helix bundle Hypothetical mechanisms for binding to human IgG antibodies by an IgG-binding domain of SpA. (a) A rearrangement mechanism , in which there are minor structural changes in the relative orientation of helix 1 in going from the free to the IgG-bound state. (b) Direct binding mechanism in which the orientations of the three α-helices are identical in the free and IgG-bound states. Montelione etal; Journal of Molecular Biology Volume 272, Issue 4, 3 October 1997, Pages 573–590

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Staphylococcus 10 Staphylococcus aureus protein A bound to Fab (1DEE) and bound to an immunoglobulin Fc in its minimized form (1L6X) Source: Wikipedia

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Staphylococcus 11 Björn Nilsson etal Journal of Immunological Methods Volume 201, Issue 1, 14 February 1997, Pages 25–34 A three-dimensional representation of Fc 1 interacting with one domain of SpA

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Staphylococcus 12 Immunomodulatory molecules used by S. aureus to alter the host immune response, including the superantigens (sAgs) enterotoxins and toxic shock syndrome toxin-1 that bind the MHC class II receptor to T-cell receptors; protein A, which binds immunoglobulin M (IgM) V H 3 on B cells; and the MHC class II analogue protein Map, which binds the T-cell receptor (TCR). Timothy J. Foster; (December 2005) Nature Reviews Microbiology 3 , 948-958

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Staphylococcus 13 Expression of spa (Protein A) is regulated in S. aureus by multiple interactions between regulators. Bronner etal; FEMS Microbiology Reviews Volume 28, Issue 2, May 2004, Pages 183–200

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Staphylococcus 14 Panton Valentine Leukocidin Toxin ( PVL) Synergohymenotropic toxin, i.e., it acts through the synergistic activity of 2 non-associated secretory proteins, component S and component F β - Pore forming toxin Its acquired through a prophage gene ( Φ- PVL) Activates human neutrophils before creating lytic pores sensitive to monovalent cations, thereby damaging the cellular membrane Andrew Labelle PCCSU Article | 11.03.08

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Staphylococcus 15

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Staphylococcus 16 Staphylococcus Coagulase Bound Free Clumping factor (Bound Coagulase) Fibrin Clot formation Prothrombin activity Free Coagulase (Eight types; Coagulase A is most common) CRF (Coagulase reacting factor)

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Staphylococcus 17

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Staphylococcus 18

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Staphylococcus 19 Regulation of ß-lactam resistance. BlaR1, 2 and MecR1, 2 represent proteins that detect ß-lactam antibiotics in the environment. Once the antibiotics are detected, the BlaR2 or MecR2 proteins become activated, and degrade the BlaI or MecI proteins. As a result resistance proteins (ß-lactamase or PBP2a) are produced and render the cell resistant to these antibiotics.

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Staphylococcus 20 Laboratory diagnosis Sample- Sample as per Clinical conditions Transport Liquid Stuart or Amies gel medium Preliminary: Gram stain- Gram positive cocci in clusters Culture- Nutrient agar and blood agar

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Staphylococcus 21 Mannitol Salt Agar 7.5% sodium chloride as a selective agent Phenol red is the indicator for mannitol fermentation

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Staphylococcus 22 Baird-parker Agar

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Staphylococcus 23

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Staphylococcus 24

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Staphylococcus 25

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Staphylococcus 26

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Staphylococcus 27 Source: www.microrao.com

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Test S. aureus S. epidermidis S . saprophyticus Coagulase Positive Negative Negative Novobiocin sensitivity Sensitivie Sensitive Resistant Acid from mannitol fermentation anaerobically Positive Negative Negative Phosphatase Positive Positive 28 Staphylococcus

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Staphylococcus 29 Additional tests Geno Type ® Staphylococcus DNAase Test StaphTEX™ Blue

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Staphylococcus 30 Francisco etal. Braz. J. Microbiol. vol.41 no.2 São Paulo Apr./June 2010

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Staphylococcus 31 Spectra MRSA medium plated with methicillin-resistant Staphylococcus aureus . The ability of Spectra MRSA to identify methicillin-resistant S. aureus based on the color of the colony, in which colonies of methicillin-resistant S. aureus appear denim blue, is shown.

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Staphylococcus 32 Rovira etal International Journal of Food Microbiology Volume 54, Issue 3, 25 March 2000, Pages 189–195

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Staphylococcus 33 Methicillin resistance gene SCCmec elements commonly share the following characteristics. (1) They carry a mec gene complex (mec). (2) They carry a ccr gene complex (ccr). (3) They have characteristic directly-repeated nucleotide sequences and inverted complementary sequences at both ends. (4) They integrate into ISS (integration site sequence for SCC), which is located at 3’ end of orfX.

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Staphylococcus 34 SCC mec type: defined by the combination of mec and ccr Subtypes: Defined by the structural differences in J1, -2 and -3 regions

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Staphylococcus 35 http://web.mit.edu/angles/Oran_Payne.htm

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Staphylococcus 36 Staphylococcus Bacteriophage typing Phage groups Group I Group II Group III Group IV Others

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Staphylococcus 37

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Staphylococcus 38 Nature Reviews Microbiology 2, 95-108 (February 2004) Staphylococcus aureus biofilms

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Staphylococcus 39

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Staphylococcus 40

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