(Ali_Zahid)association_of_antibiotic_resistance_with_the_occurance_of_a_particular_plasmid[1].pptx

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1. Association of Antibiotic Resistance With The Occurance of a Particular Plasmid Presented By: Ali Zahid 2012-ag-2652

2. Presentation outline : Introduction Properties of plasmid Antibiotic plasmid Mechanisms of resistance specified by plasmid Conclusion

3. Introduction The rapid dissemination of antibiotic resistant pathogens threatens human as well as animals health and may have significant social and financial impacts. It is well recognized that applications of antibiotics in human clinical therapy, aquaculture, and food animal production all contribute to the emergence and amplification of pathogens due to selective pressure

4. Continue.. A broad spectrum of commensal bacteria, including lactic acid bacteria, have been identified as being carriers of AR genes and are able to horizontally transfer those genes to other bacteria, leading to increased resistance in the recipient organisms and Plasmids have been directly implicated in the acquisition of resistance to many antibiotics (Feld et al., 2009)

5. Continue.. Plasmids are small circular pieces of extra chromosomal DNA that replicate independently from the host's chromosomal DNA (Bennett, 2008)

6. Properties of the Resistant Plasmid 1:Must be able to replicate it own DNA independently 2:Must have origin of replication and origin of transfer 3:Must carry the antibiotic resistance genes

7. Antibiotic Resistance Plasmid

8. Transfer of Resistant Plasmids

9. Mechanisms of antibiotic resistance specified by plasmid By carrying resistance genes which produces enzymes that inactivate the antibiotic e.g β- Lactams where β lactamases are produced and chloramphenicol where acetyl transferase inactivate the drug to 3ꞌ - acetoxy chloramphenicol. Carrying a mutated gene which lead to impaired transport across the membrane i.e causes decrease in permeability of antibiotic e.g mutation on UNC gene which impair transport of gentamicin.

10. Continue.. Alteration of target site e.g MecA gene in Staphylococcus aureus which produces penicillin binding protein 2ꞌ that confer resistance to methicillin. By pass mechanism is another way plasmid cause antibiotic resistance.

11. Conclusions Plasmid encoded resistance to antibiotic by microbial cells is due to R-plasmid carrying antibiotic resistance gene. A copy of this plasmid is transferred to a recipient through conjugation with all the resistance gene and character which expresses the resistance in the donor.