Antibiotic resistance occurs when microbes become less treatable by antibiotics due to genetic changes. It was first discovered by Alexander Fleming in 1945, who warned about the emergence of resistance. There are several mechanisms by which bacteria become resistant, including blocking antibiotic entry, modifying the antibiotic target, or actively pumping out antibiotics. The overuse and misuse of antibiotics, especially broad-spectrum antibiotics, in human medicine, agriculture, and animal husbandry has accelerated the development and spread of antibiotic resistance, threatening our ability to treat bacterial infections. New approaches are needed to manage the growing problem of antibiotic resistance.

2. ANTIBIOTIC RESISTANCE
It is when microbes are less treatable with one or more antimicrobial medications used
to treat or prevent Infection.

3. First discovered by A. Fleming . Brought into widespread use in 1940s.
He himself warned about the dangers of the resistance in his NOBEL PRIZE LECTURE in 1945.
“It is not difficult to make microbes resistant
to penicillin. In the laboratory by exposing
them to concentrations not sufficient to kill
them and the same thing has occasionally
happened in the body …….and by exposing
his microbes to non-lethal quantities of the
drug make them resistant.”

4. TIMELINE OF ANTIBIOTIC RESISTANCE

5. • Resistant organisms lead to treatment
failure.
• Increased mortality.
• Resistant bacteria may spread in
community.
• Low level resistance can go undetected.
• Added burden on healthcare costs .
• Threats to return to pre – antibiotic
era.
• Selection pressure.
WHY RESISTANCE
IS CONCERN ?

7. http://www.tufts.edu/med/apua/about_issue/about_antibioti
cres.shtml
http://www.smallworldinitiative.org/

8. RESISTANCE TO ANTOBIOTICS
• DENIED ACCESS : Membranes become impermeable to antibiotic
• ANTIBIOTIC MODIFICATION : Some bacteria have enzymes that cleave or modify antibiotics.
• ALTERED TARGET SITE: Antibiotic cannot bind to its intended target because the target itself is modified.
• PUMPING OUT the antibiotic faster than it gets in.
• ALTERNATIVE TARGETS (typically enzyme) : eg alternative penicillin binding protein .

9. SUPERINFECTION
THE USE OF BROAD SPECTRUM
ANTIBIOTICS RATHER THAN NARROW
SPECTRUM DRUGS IS KNOWN TO
FAVOR THE EMERGENCE OF
RESISTANCE BY BROADLY ELIMINATING
COMPETING SUSCEPTIBLE FLORA
LEADING TO THE RISE IN RESISTANCE

11. GENETIC BASIS OF RESISTANCE
They either change the target of
the drug so that the drug doesn’t
bind or change the membrane so
that drug don’t penetrate well
Occurs at low frequency Usually
affect one drug or one family of
drugs. CHROMOSAL MUTATION

12. PLASMID
• Plasmid cause drug resistance
by encoding enzymes that
degrade or modify drugs.
• Occurs at high frequency.
• Affect multiple drugs or
family of drugs

13. Resistant plasmids usually two
sets of genes. One set encodes
the enzymes that degrades or
modify the drugs and other
encodes the proteins that
mediate conjugation,the main
process by which resistance
genes are transferred from one
bacterium to another. RESISTANT PLASMIDS

14. • Transposons are small pieces of DNA
that move from one site on bacterial
chromosome to another or from the
bacterial chromosome to plasmid DNA.
• Transposons often carry drug resistant
genes.
• Many R chromosomes carry one or
more transposons. TRANSPOSONS

15. Prescriber
Related
DRUG
RELATED
ENVIRONMENTAL
FACTORS
PATIENT
RELATED
FACTORS CONTRIBUTINGTO RESISTANCE

16. • Huge population and overcrowding.
• Rapid spread by better transport
facility.
• Poor sanitation.
• Increases community required
resistance.
• Ineffective infection control program.
• Widespread use in animal husbandry
and agriculture. ENVIRONMENTAL FACTORS

17. • Over the counter availability of
antimicrobials.
• Counterfeit and substandard drug
causing sub optimal blood concentration.
• Irrational fixed dose combination of
antimicrobials.
• Soaring use of antibiotics.
DRUG RELATED

18. • Poor adherence of dosage
regimes
• Poverty
• Lack of santation
• Lack of education
• Self-medication
• misconception
PATIENT RELATED

19. • Inappropriate use of available
drugs.
• Increased empiric poly –
antimicrobial use.
• Overuse of anti – microbials
• Inadequate dosage
• Lack of current knowledge and
training
PRESCRIBER RELATED

20. PHAGE THERAPY
MOBILISATION OF
HOST DEFENSE
MECHANISMS
USE OF NORMAL
BACTERIAL FLORA
DEVELOPMENT OF NEW
ANTIBIOTICS
LIMITING SPREAD OF
DRUG RESITANT BACTERIA
MANAGING DRUG RESISTANT PROBLEM

21. REFERENCE
• http://www.who.int/mediacentre/factsheets/fs194/en/
• http://www.fda.gov/ForConsumers/ConsumerUpdates/ucm092810.htm
• http://www.cdc.gov/drugresistance/