1 / 20

Global Antibiotic Use and the Rise of Resistance

Global Antibiotic Use and the Rise of Resistance. BioQUEST Summer Workshop June 12 – 13, 2010 Julie Seiter, Oakland Community College Ethel Stanley, BioQUEST, Beloit College. Staphylococcus aureus:. Routinely colonizes in humans, domestic animals, and livestock

cahil
Download Presentation

Global Antibiotic Use and the Rise of Resistance

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Global Antibiotic Use and the Rise of Resistance BioQUEST Summer Workshop June 12 – 13, 2010 Julie Seiter, Oakland Community College Ethel Stanley, BioQUEST, Beloit College

  2. Staphylococcus aureus: • Routinely colonizes in humans, domestic animals, and livestock • Found in 25% to 35% of healthy human individuals on the skin or mucous membranes • Occasionally acquires enhanced virulence and antimicrobial resistance • Can invade tissue via any injury that compromises epithelial integrity, trauma, medical or surgical interventions, or viral infections

  3. Visualizing Resistance with Online Data and Tools • During a 6 month period (Sep 2006 - April 2007), researchers collected 2,890 methicillin-susceptible S. aureus(MSSA) and methicillin-resistant S.aureus (MRSA) isolates from invasive infections of patients from 26 European countries. • All isolates characterized by the variable region of the staphylococcal spa gene (spa typing) Grundmann H, Aanensen DM, van den Wijngaard CC, Spratt BG, Harmsen D, et al. 2010. PLoS Med 7(1): e1000215 .Geographic Distribution of Staphylococcus aureusCausing Invasive Infections in Europe: A Molecular-Epidemiological Analysis.

  4. Typing Staphylococcus Look for loci with short sequence repeat (SSR) with regions that offer suitable variability for discriminating outbreaks Two S. aureusgenes that are highly conserved within the species are protein A (spa) and coagulase (coa) 186 spa types have been identified and catalogued in a relational database

  5. Group Task: Explore the Data Mapping Use the interactive mapping tool to gather information on the dynamics and/or the genetics of the S. aureuspopulations – both MSSA and MRSA. Be prepared to share your findings with an example. Get started by going to: http://www.spatialepidemiology.net/srl-maps/

  6. Group Sharing

  7. Wordle www.wordle.net

  8. What is antibiotic resistance? • Antibiotic resistance often confused with virulence • Virulence refers to factors that enable a bacterium to attach to host cells, invade tissue, avoid the immune system, form biofilms and establish an infection • Antibiotic resistance refers to the ability of a bacterium to grow in the presence of antibiotics

  9. Mechanisms of Antibiotic Resistance http://www.textbookofbacteriology.net/resantimicrobial_3.html

  10. Mechanisms of Antibiotic Resistance http://www.textbookofbacteriology.net/resantimicrobial_3.html

  11. Spread of Antibiotic Resistance • Vertical transmission: Genes passed to cell’s offspring • Horizontal transmission: Genes passed to other cells of the same or different species • Conjugation – cell to cell contact * • Transformation– naked DNA picked up by cells • Transduction – viruses carry genes to new cells * Conjugation may be most common method of horizontal transfer

  12. Conjugation Marian Koshland Science Museum of the National Academy of Science: http://www.koshland-science-museum.org/exhib_infectious/antibiotics_04.jsp

  13. Marian Koshland Science Museum of the National Academy of Science: http://www.koshland-science-museum.org/exhib_infectious/antibiotics_04.jsp

  14. What is the origin of resistance genes? • In nature antibiotics function at low concentrations in metabolic and regulatory pathways • Antibiotic resistance genes coevolved with these “antibiotics” • In nature resistance genes may function in detoxification of metabolic intermediates; inhibition of virulence factors; regulation of signal trafficking • In clinical settings, the high concentrations of antibiotics apply selective pressure and the most important function of the genes is for resistance to the deadly effects of the antibiotic

  15. Resistance genes evolved in nature  Moved to humans in commensal bacteria  Evolved in pathogenic bacteria What effect will they have back in nature? José L. Martínez, et al., Science 321, 365 (2008)

  16. Selection for Antibiotic Resistance Bacteria Antibiotic use in animals • Use: growth promoters and for prophylactic treatment • 70% of the antibiotics and similar drugs used in the US go into animal feeds • Sensitive bacteria killed over time and resistant ones survive www.keepantibioticsworking.com/

  17. Selection for Antibiotic Resistance Bacteria Antibiotic use in animals • Similar antibiotics are used in animals and humans • Resistant organisms spread to humans: • via food • via farm workers  community • via environment

  18. Selection for Antibiotic Resistance Bacteria Antibiotic use in animals • Example: • US permitted fluoroquinolones in poultry feed in 1995 • Dramatic increase in antibiotic-resistant Campylobacter (diarrhea) cases associated with eating and handling poultry • EU banned antibiotics from animal feeds in 2006 • Denmark banned antibiotics in 1998 with interesting results

  19. Danish researchers found that reducing use of the antibiotic tylosin in pig feed correlated with a decline in bacterial resistance to the human equivalent -erythromycin http://www.keepantibioticsworking.com/new/resources_library.cfm?refID=69872

More Related