Drug Resistance 2

8/8/2019 Drug Resistance 2

http://slidepdf.com/reader/full/drug-resistance-2 1/17

SEMINAR PRESENTED BY HASSANA AL-MUSTAPHA

U04NS1056

SUPERVISED BY DR. U. E UMANA

DRUG RESISTANCE



INTRODUCTION

y Chemotherapy is the primary means of treatingparasitic infections.

y The potential for resistance was recognized as early

as in the 1940s when antibiotics were firstintroduced.

y Significant increase in resistance have been notedonly in the last two decades.

y



INTRODUCTION

y The emergence of drug resistance in several majorinfectious disease including tuberculosis (TB),Human-immunodeficiency virus(HIV)/Acquired

immune deficiency syndrome(AIDS), malaria, bacterial infection and diarrheal diseases began to be recognized as a global threat in 1990s.



y Drug resistance refers to the ability of an organismsuch as the HIV virus, the TB bacillus or cancercells to over come the effect of a drug prescribed todestroy it. For example the resistance of the HIV

virus to Azidothymidine(AZT) or that of TB toantibiotics.

Definition



Classification

y Bacterial (antibiotic resistance)

y Endo-parasites

y Viruses

y Fungi

y Cancer cells



Causes

y Exposure to low level drugs.

y Ability of the pathogenic organisms to mutate

y Replication of cancer cells.

y Treatment of animals with antibiotics.

y Failure to complete a course of drug and overprescription of antibiotics.

y Unreliable access to drugs paired with incompletecourse.



Promoters Of Resistance

In the hospital environment:

y Increasing use of powerful antibiotics.

y Advanced medical technology.

yPoor infection control practices inhospitals.



Promoters Of Resistance

Outside the hospital environment

y O ver use of drugs especially antibiotics in outpatient medicine.

y The use of antibiotics in agriculture exertselective pressure for the emergence of resistantantibiotic strains.

y Increasing number of children in close contact atday care centre and by more national andinternational travel.



Drug Action

y Drugs act by specifically interfering with cellular or biochemical processes.

y The two types of drugs are:

Agonists- they stimulate and activate thereceptors.

Antagonists ± they stop the agonists fromstimulating the receptors.



Physiological adaptations

Differential selection of resistantindividuals from a mixed population of susceptible and resistant individuals.

Spontaneous mutations followed by selection.

Changes in gene expression. (geneamplification)

Potential modification involved indrug resistance



Mechanism of drug resistance

. Alteration of the target site of the drug.

y Enzyme inactivation of the drug.

y Active transport of the drug out of the microbialcell.

y Decreased permeability of the microbial cell wall tothe drug.



Mechanism of antibiotics resistancey Active transport systems

(efflux pumps) have beendescribed for the removalof some antibiotics such as

tetracycline, macrolidesand quinolones from

bacterial cells.

y Bacteria are intrinsically

resistant to many drugs based solely on the factthat drugs cannotpenetrate cell wall or cellmembrane.



Mechanism of antibiotics resistance

y By altering the targetsite to which anantibiotic must bind.

y By producing enzymethat inactivates the drugknown as I2 lactamasesfor example I2 lactam

antibiotic (penicillinand cephalosporin).



Antimicrobial (Drug) Resistance

Diagram showing the difference between non-resistant bacteria and drug resistant bacteria. Non-resistant bacteria multiply, and upon drug treatment, the bacteria die. Drug resistant bacteria multiply as well, but upon drug treatment, the bacteria continue tospread.



Treatments

y Accurate and rapiddiagnosis.

y Drug combination.

y New drugs.



Control

y An ongoing program to decrease the use of antibiotics both in the clinics and an agriculture

will be necessary.

y The increase use of vaccine to prevent infectionscan help limit the need for antibiotics.

y The development of novel classes of antibiotics tofight emerging resistant bacteria will be required.



y K aspers, G. J. L., R. Pieters, and A. J. P. Veerman,editors. Drug Resistance in Leukaemia and

Lymphoma III ( New York: Plenum Press, 1999.

y Broxterman, H. J., and N. Georgopapadakou."Cancer Research 2000: Drug Resistance, New Targets and Drugs In Development." Drug

Resistance Updates 3 (June 2000): 133-138.

y Stephen H. Gillespie, and Timothy D. McHugh thebiological cost f antimicrobial resistance

REFERENCE

Drug Resistance 2

Documents

Transcript of Drug Resistance 2