antbiotic resistance

Antimicrobial

ResistanceDr Karuna Sree P

Asst. Professor

Dept. Of Pharmacology

KIMS

Contents

History

Antimicrobial resistance

Mechanisms of antibiotic resistance

Strategies to contain resistance

Develop new antibiotics

Judicious use of antibiotics

Indian scenario

Antibiotic policy at KIMS

Summary

3/23/20152 Dr Karuna Sree p, Dept. Of Pharmacology

Evolution of Chemotherapy

A pre- Ehrlich era before 1891

The period of Paul Ehrlich

Magic bullets

The period after 1935 – highlighted by

the discovery of sulfonamides &

antibiotics


In his 1945 Nobel Prize lecture, Fleming himself

warned of the danger of resistance –

“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.”

History Nobel Lecture, December 11, 1945

Sir Alexander

FlemingThe Nobel Prize in

Physiology or Medicine 1945


…EVOLUTION OF RESISTANCE TO

ANTIBIOTIC


Timeline of Antibiotic Resistance


??? antimicrobial resistance

Infections with resistant organisms are associated

with increased morbidity and mortality

Extended stays in hospitals

Reduced treatment options - Untreatable infections

Increased healthcare costs

Compromises health security, damage trade &

Economy

Patients with an antimicrobial-resistant

infection may suffer more and pay more

for treatment.http://www.cdc.gov/drugresistance/about.html


Where antimicrobial resistance is present

It is a serious global challenge.

Every continent and country faces the menace of

antibiotic resistant “super bugs.”

Very high rates of resistance observed in

common bacteria (for eg., E. coli, K.pneumoniae

& Staph.aureus, gonorrhoea) that cause

common health-care associated & community-

acquired infections


Bacterial evolution Vs mankind’s ingenuity

11

• Adult humans contains 1014 cells,

only 10% are human – the rest are

bacteria

• Antibiotic use promotes Darwinian

selection of resistant bacterial

species

• Bacteria have efficient mechanisms

of genetic transfer – this spreads

resistance

• Bacteria double every 20 minutes,

humans every 30 years

• Development of new antibiotics has

slowed – resistant microorganisms

3/23/2015Dr Karuna Sree p, Dept. Of Pharmacology

Selection Pressure

Bacteria Sensitive to antibiotic

Bacteria Resistant to antibiotic

After

Antibiotic

Use


Antimicrobial resistance

Antimicrobial resistance is a broader

term, encompassing resistance to

drugs to treat infections caused by

bacteria as well as parasites (e.g.

malaria), viruses (e.g. HIV) and fungi

(e.g. Candida)

http://www.who.int/mediacentre/factsheets/fs194/en/


Other similar terms

Antibiotic tolerance : when the antibiotic no

longer kills the microorganisms but merely

inhibits its growth / multiplication.

Tolerant microorganisms grow after

antibiotic is stopped whereas resistant

microorganisms multiply even in the

presence of antibiotic.


Factors contributing to Antibiotic

Resistance

Environmental

FactorsDrug

Related

Factors

Patient

Related

Factors

Prescriber

Related

Factors

Antibiotic

Resistance


1. Environmental Factors

Huge populations and overcrowding

Rapid spread – increased travelling

Poor sanitation

Increases community acquired resistance

Ineffective infection control program

Widespread use of antibiotics in animal husbandry

and agriculture and as medicated cleansing products


Widespread Use of Antimicrobials in Animal

Husbandry and Agriculture

The extensive worldwide exploitation of

antibiotics in animal care (medicated animal

feed) and agriculture (growth promoters)

constantly selects for strains of bacteria that are

resistant to the drugs.


2. Drug Related

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

Policy

Decision

at Higher

level3/23/201519 Dr Karuna Sree p, Dept. Of Pharmacology

Soaring Antibiotic Use

Antibiotic use (and misuse) has soared since the

first commercial versions were introduced and

now includes many nonmedicinal applications.

2 >50Million

TonMillion

Ton

1954 2014


3. Patient Related

Poor adherence of dosage Regimens

Poverty

Lack of sanitation concept

Lack of education

Self-medication

Misconception

Patient

Counseling,

Awareness

Program 3/23/201521 Dr Karuna Sree p, Dept. Of Pharmacology

Physician / Prescriber Related

Inappropriate use of available drugs

Increased empiric poly-antimicrobial use

Overuse of antimicrobials

Inadequate dosing

Lack of current knowledge and training


DEVELOPMENT OF RESISTANCE:

Emerging and Re-emerging Diseases

Emerging and re-emerging diseases are another source

for resistance.

Emerging diseases have not been seen before.

Re-emerging are caused by organisms

resistant to treatment. For eg., In India NMEP changed to NVBDCP due to

remerging of disease


DEVELOPMENT OF RESISTANCE:

Emerging and Re-emerging Diseases

• 2008 – outbreak of H1N1 virus

• 2014 - outbreak of Ebola virus3/23/201524 Dr Karuna Sree p, Dept. Of Pharmacology

How the bacteria develops

resistance ?


Antibiotic Resistance

Natural

Lack of metabolic process / target site

Acquired

Genetic methods

Chromosomal methods -Mutation

Extra chromosomal

methods –Plasmids

Within /between bacteria

Biochemical mechanisms

By producing enzymes

Preventing drug accumulation

Modifying target site

Use alternative pathways

Quorum sensing3/23/201526 Dr Karuna Sree p, Dept. Of Pharmacology


Some microorganisms may ‘born’ resistant,

some ‘achieve’ resistance by mutation or

some have resistance ‘thrust upon them’ by

plasmidsSome are born great, some achieve

greatness or some have greatness thrust

upon them3/23/201527 Dr Karuna Sree p, Dept. Of Pharmacology

Natural / Intrinsic Resistance

It occurs naturally.

1. Lack target :

• No cell wall; innately resistant to penicillin

2. Innate efflux pumps:

• Drug blocked from entering cell or ↑

export of drug (does not achieve

adequate internal concentration). Eg. E.

coli, P. aeruginosa

3. Drug inactivation:

• Cephalosporinase in Klebsiella3/23/201528 Dr Karuna Sree p, Dept. Of Pharmacology

Acquired resistance

MUTATIONS

• It refers to the change in DNA structure of the gene.

• Occurs at a frequency of one per million cells.

• Even though Mutation rate is low → during course of therapy – sensitive strains die – resistant strains

continue to grow & multiply – selection of mutants

• Single step / Multistep

• Eg.Mycobacterium.tuberculosis,Mycobacteriumlepra , MRSA.

• Often mutants have reduced susceptibility 3/23/201529 Dr Karuna Sree p, Dept. Of Pharmacology

Plasmids – carriers of DNA

• Replicate independently and freely in cytoplasm.

• R-plasmids : Those which carry genes resistant

(r-genes) to antimicrobials

• r-Genes readily transferred from one R-plasmid

to another plasmid or to chromosome.

• Much of the drug resistance

encountered in clinical practice

is plasmid mediated


Methods of plasmid mediated transfer of

antibiotic resistance

• Transfer of r-genes from one bacterium to another

Conjugation

Transduction

Transformation

• Transfer of r-genes between plasmids within the bacterium

By transposons

By Integrons


Transfer of Plasmid : Conjugation

Main mechanism for spread of resistance(single

/ multidrug)

The conjugative plasmids make a connecting

tube (sex pili) between the two bacteria through

which plasmid itself can pass.

Commonly observed in bacteria present at high

density – as in gut.


Bacterial Conjugation


Transduction

Less common method

The plasmid DNA enclosed in a bacteriophage

(bacterial virus) is transferred to another

bacterium of same species.

Seen in Staphylococci , Streptococci


Bacterial Transduction


Transformation

It poses least clinical problem.

Free DNA is picked up from the environment by

the bacteria (from a cell belonging to closely

related or same strain).

New DNA is incorporated into the genome &

becomes resistant.


Bacterial Transformation


by Transposons

Transposons are DNA segments that cannot selfreplicate but can self transfer between palsmids /plasmid to chromosome.

The donor plasmid containing the Transposons,co-integrate with acceptor plasmid & replicateduring cointegration.

Both plasmids then separate and each containsthe r-gene carrying the transposon.

Eg., Staphylococci, Enterococci


Resistance mediated By transposons


by Integrons

Integron is a large mobile DNA

unit, can spread Multidrug

resistance

Packed with multiple gene

casettes, consisting of a

resistance gene attached to a

small recognition site.

They encode several bacterial

functions. Eg. resistance &

virulence.

They cannot promote self

transfer, so work with


Biochemical mechanisms of antibiotic

resistance

Prevention of drug accumulation in the bacterium –altering porin channels / efflux pumps

Modification/protection of the target site

Use of alternative pathways for metabolic / growth requirements

By producing an enzyme that inactivates the antibiotic

Quorum sensing3/23/201541 Dr Karuna Sree p, Dept. Of Pharmacology

Decreased permeability through Porin

channels

Example : pencillins


Efflux pumps

• Cytoplasmic membrane transport proteins.

• Major mechanism for resistance in Tetracyclines.

• Eg.,

ATP Binding Cassette

Major Facilitator Superfamily (MFS)

Multidrug And Toxic Compound Exporter (MATE)

Staphylococcal Multidrug Resistance

Transporters(SMR)

Resistance Nodulation Division Family (RND) 3/23/201544 Dr Karuna Sree p, Dept. Of Pharmacology

Efflux transporters :

Drug resistance


Modification/Protection of the Target site

Target sites Resistant Antibiotics

Ribosomal point mutation Tetracyclines,

Macrolides,

Clindamycin

Altered DNA gyrase Fluoroquinolones

Modified penicillin binding

proteins (S. pneumoniae)

Penicillins

Mutation in DNA dependant

RNA polymerase

(M.tuberculosis)

Rifampicin


Use of alternative pathways for metabolic /

growth requirements

• Resistance can also occur by alternate pathway

that bypasses the reaction inhibited by the

antibiotic.

• Sulfonamide resistance can occur from

overproduction of PABA


By producing enzymes that inactivates

antibiotic Inactivation of β-lactam antibiotics

• S. aureus, N. gonorrohoea, H.influenza, Produceβ-lactamase which cleaves -lactam ring

Inactivation of Chloramphenicol

• Inactivated by chloramphenicol acetyltransferase .

• Gram-ve (enzyme present constitutively hencehigher resistance) gram +ve bacteria (enzyme isinducible )

Inactivation of Aminoglycosides

• Inactivated by acetyl, phospho & adenylyltransferases Present in gram +ve and gram –ve .


Quorum sensing

Microbes communicate with each other and

exchange signaling chemicals (Autoinducers)

These autoinducers allow bacterial population to

coordinate gene expression for virulence,

conjugation, apoptosis, mobility and resistance.


Why named quorum sensing

Single autoinducer from single microbe is

incapable of inducing any such change

But when its colony reaches a critical

density(quorum), threshold of autoinduction is

reached and gene expression starts

QS signal molecules AHL, AIP, AI-2 & AI-3 have

been identified in Gm-ve bacteria

AI-2 QS –system is shared by GM+ve bacteria

also


WHY INHIBIT QUORUM SENSING

Proved to be very potent method for bacterial virulence inhibition.

Several QS inhibitors molecules has been synthesized which include AHL, AIP, and AI-2 analogues

QS inhibitors have been synthesized and have been isolated from several natural extracts such as garlic extract.

QS inhibitors have shown to be potent virulence inhibitor both in in-vitro and in-vivo, using infection animal models.


Strategies to control / prevent

Resistance

Develop new antibiotics

Bypass the drug resistance

Judicious use of the existing antibiotics:

Containment of drug resistance


New Antibiotic Development

Only one group of antibiotics in last 35 years

Only 15 antibiotics of 167 under development

had a new mechanism of action with the

potential to combat of multidrug resistance.

Lack of incentive for

companies to develop

antibiotics.


Hope is not exhausted….yet

Phage therapy

Use of the lytic enzymes found in mucus and

saliva

Agents that target type IIA topoisomerases

Antimicrobial peptides (AMPs), lipopeptides

(AMLPs) target bacterial membranes, making it

nearly impossible to develop resistance (bacteria

would have to totally change their membrane

composition).


Alternate Approaches

Phage therapy

• Phage Therapy is the therapeutic use of lyticbacteriophages to treat pathogenic bacteria infections animportant alternative to antibiotics

• Invade bacterial cells and disrupt bacterial metabolismand cause lysis of bacteria.

• The success rate was 80–95% with few gastrointestinalor allergic side effects. British studies also demonstratedsignificant efficacy of phages against Escherichia coli,Acinetobacter spp., Pseudomonas spp andStaphylococcus aureus.

Efflux Pump Inhibitors: verapamil3/23/201555 Dr Karuna Sree p, Dept. Of Pharmacology

Some newer antibiotics

Ceftobiprole/ceftaroline: V generation cephalosporins

Iclaprim: inhibits Dihydrofolate reductase

Telavancin: inhibition of cell wall synthesis and disruption of membrane barrier function

Dalbavancin: inhibits cell wall synthesis

Tedizolid

Oritavancin

Bedaquiline – multi drug resistant TB - approved

Delamanid – multi drug resistant TB – in trials

New approved

antibiotics -2014


Judicious Use of Antibiotics

Capable of containing antibiotic

resistance

Cannot eliminate the possibility of

antibiotic development as resistance

is an evolutionary process


Containment of Resistance

Containment of antibiotic resistance is

a multi-pronged program

Involves all stake holders Physicians

Patients

Pharmaceuticals


Patient role in containment

Finish the full course of treatment.

Do not stockpile the leftover doses

Do not medicate yourselves

Do not treat your family and friends


Strategy of Containment


Evolutionary Process

Faulty Use of Antibiotics

Hospital Environmental

Empirical Use

Definitive Use

Community Acquired Antibiotic

Resistance

Hospital Acquired Antibiotic Resistance

Use of antimicrobials before

pathogen responsible for a

particular illness or the

susceptibility to a particular

antimicrobial is known3/23/201560 Dr Karuna Sree p, Dept. Of Pharmacology

Faulty Antibiotic Use

Antimicrobials are over prescribed

Available without prescription - i.e., over the

counter drugs


Over Prescribed Antibiotics

Clinician should first determine whether

antimicrobial therapy is warranted for a given

patient


Empirical Microbial Selection

Indicated on the basis of clinical findings?

Is it prudent to wait until such clinical findings

become apparent?

Can some simple bed side test done to confirm

your suspicion? Microscopy

Gram staining

Have appropriate clinical specimens been obtained

to establish a microbial diagnosis?

What are the likely etiological agents



What measures should be taken to protect

individuals exposed to the index case to prevent

secondary cases (1), and what measures should

be implemented to prevent further exposure (2)?

12 3/23/201564 Dr Karuna Sree p, Dept. Of Pharmacology

Infection control

Simple measure of hand wash

prevents many infections.

Alcohol hand rub to be used

between patient contact



Is there clinical evidence (e.g. from clinical

trials) that antimicrobial therapy will confer

clinical benefit for the patient?

(Evidence-based medicine)


Definitive Treatment

• Can a narrower spectrum agent be

substituted for initial empiric drug?

• Is one agent or combination of agents

necessary?


Examples

-lactam + Aminoglycosides

Extended spectum Penicillins + -lactamase

Inhibitors

Anti-tubercular regimen

Anti-leprotic regimen

Co-trimoxazole

Artemisinin based Combination Therapy (ACT) in

Malaria



What is the

Right dose

Right route of administration

Right duration of therapy?


Definitive treatment

What specific test to identify patients

who will not respond to treatment?



What adjunctive measures can be

undertaken to eradicate infection?

Vaccination

Steroid

Drainage of pus

Amputation

Removal of catheter


Who’s Work?

Microbiologist

Physician

Pharmacologist

Advise the

proper and

adequate

antibiotics with

balancing the

economy of

hospital3/23/201572 Dr Karuna Sree p, Dept. Of Pharmacology

Indian scenario

Currently no functioning national antibiotic policy

or a national policy

No restriction on Over The Counter (OTC)

dispensing of antibiotics

Indian hospitals have varying standards of

infection control.

Some hospitals reported very high Gram-negative

resistance rates, with very high prevalence of

ESBL(Extended Spectrum Beta Lactamases)

producers – resistant to imipenems & only sensitive to

colistin


Indian scenario

A Roadmap to Tackle the Challenge of

Antimicrobial Resistance - A Joint meeting of

Medical Societies in India – organised in 2012 :

lead to evolution of CHENNAI DECLARATION

Stake Holders : Ministry of health, DCGI, state, MCI,

NABH, Infection control team(ICT) in all hospitals, ICMR,

to standardize the laboratories, National task force for

vigilance, to interact with global organizations - WHO and

the involvement of medical professionals, societies,

NGOs, journals, media, public as well as veterinary

practice.


Ghafur A, Mathai D, Muruganathan A, Jayalal JA, Kant R, Chaudhary D, et al. "The Chennai Declaration“ Recommendations of "A

roadmap- to tackle the challenge of antimicrobial resistance" - A joint meeting of medical societies of India. Indian J Cancer

2012;49:84-943/23/201575 Dr Karuna Sree p, Dept. Of Pharmacology

Hospital Acquired Drug Resistance

Hospital infection control committee &

Antibiotic policy

Hospital Antibiogram

Hospital specific antibacterial Resistance Pattern

Identification of potential pathogen most likely to

cause infection

Previous antibacterial therapy

Prescription auditing


Hospital infection control committee

Leadership of infection control specialist

Team members Medical superintendent

General manager

Housekeeping supervisor

Operation theater in-charge

Chief executive officer

Medical director

Representatives of major departments.

Antibiotic steward - for giving second opinion

The committee should meet at least once in three months and discuss important infection control issues The level of compliance to antibiotic policy

Antibiotic resistance pattern (antibiogram)

The compliance to infection control guidelines


Hierarchy of

infection control

committee


Veterinary antibiotic usage

Clinical & epidemiological

evidence s/o passage of

resistant strains from animals

to humans

Some countries reported 50% of

antimicrobials being used in agriculture

/ animal husbandry.

In India magnitude is not well studied3/23/201579 Dr Karuna Sree p, Dept. Of Pharmacology

Methods to curb the spread of resistance from

animals to human

Need to evaluate the extent & indications of use.

Need to ascertain and monitor the prevalence of resistant bacteria, like zoonotic food borne bacteria in animals

Need to quantify the rate of transfer of medically-relevant resistance genes & bacteria from animals to humans.

Regular monitoring antibiotic residues in food of animal origin

Formulation/implementation of proper regulations for observance of withholding or withdrawal periods between the use of antibiotics and animal slaughter or milking to avoid residues of antibiotics in milk and meat.


Hospital Antibiotic Policy - KIMS

To curb the common misuse and overuse of

antibiotics

Restricts the occurrence of antibacterial

resistance among the hospital strains

Controls the spread of such infections to

susceptible and critically ill patients in the

hospital and the subsequent infection into the

community.

Saves money for the patient and increases

patient satisfaction with decreased side effect


Hospital Antibiogram

A periodic summary of antimicrobial

susceptibilities of local bacterial isolates

submitted to the hospital's clinical

microbiology laboratory.

Used by clinicians to assess local

susceptibility rates, as an aid in selecting

empiric antibiotic therapy, and in monitoring

resistance trends over time within an

institution


Antibiogram of KIMS Hospital

Am

ox+

CA

Gent

a

Ami

ka

Nitrof

urant

oin

Norfl

ox

Cotri

moxa

zole

Cefta

zidim

e

Cefta

zidim

e+

CA

Piper

icilin

+

Tazo

Imipe

nem

E.coli 14.8 52.3 89.6 76.4 15.62 19.3 8.82 60 20 100

Klebsiell

a

0 66.66 100 45.4 50 60 9.09 100 0 100

Pseudo

monas

0 50 50 Tobra

100

50 0 Netil

100

0 50 100

Acineto

bacter

25 50 50 0 25 50 0 0 50 100

Proteus 100 100 100 --- 50 0 0 --- 100 ---

Susceptibility pattern of gram negative isolates

from urine (% senstivity)


Antibiogram of KIMS Hospital

Susceptability pattern of Gram positive isolates

(% sensitivity)

Organis

m

Ampi

cillin

Amo

x +

CA

G Amik

a

Cipr

o

Cefo

xitin

Cotri

m

Eryth

ro

Piper

cilin+

TZ

Vanc

omyc

in

Staph.a

ureus

40 40 80 100 40 40 100 40 --- 100

Enteroc

occus

0 66.66 66.66 66.66 0 --- --- ---- 66.66 100

Pneumo 66.66 66.66 100 0 33.3

3

--- 0 66.66 ---- 100

Enteroc

occus

(urine)

-- 50 12.5 28.57 15.3

8

--- --- --- 12.5 100


Summary

Target definitive therapy to known pathogen

Treat infection, not contamination

Treat infection, not colonization

Know when to say “no” to higher antibiotics

Isolate Pathogen

Break the chain of contagion – Keep your hands

clean.

Start simple bed side test: Gram stain,

microscopy 3/23/201585 Dr Karuna Sree p, Dept. Of Pharmacology

Thank Q


antbiotic resistance

Health & Medicine

evolution of resistance

microbes resistant

resistant microorganisms

resistant organisms

danger of resistance

new antimicrobial agents

high rates of resistance

end of antimicrobial