Antibiotic Resistance - Applied Microbiology - Lecture Slides, Slides of Microbiology

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ANTIBIOTIC RESISTANCE IN

PATHOGENIC MICROORGANISMS:

AN OVERVIEW

WHAT IS AN ANTIBIOTIC?

“An agentcapable ofinhibiting bacterialgrowth or killingbacteria.”

For us, this istypicallyrecognized as acategory ofmedicine.

WHY SHOULD WE BE CONCERNED?^ •

Increases number of infection and mortality ratesfor diseases that were previously consideredcurable

Increases cost in health care facilities

Jeopardizes the herd immunity of the society

Provides further complications for other illnesses

Jeopardizes global trade relationships with othercountries

RETURN TO THE PRE-ANTIBIOTIC ERA? •

The majority of sexually transmitted infections (STIs)are still untreatable except for: syphilis, gonorrhoea,chlamydia and trichomoniasis

Gonorrhoea was

previously treated

with Penicillin,

tetracycline, fluoroquinlones

Treatment now is restricted to ceftrixaxone incombinational drug therapy…but there has beenprevalence of drug resistant strains.

STAPHYLOCOCCUS AUREUS

Penicillin resistant in 1947

Methicillin resistant (MRSA) strain in 1961

Resistance to tetracycline anderythromycin…leaving vancomycin until the 1990s

New class of antibiotics such as oxaxoldionesappeared to treat MRSA strains

Resistance documented in some cases in 2002 and 2011

ANTIBIOTIC DISPENSARY CONTROL

Microbiologist recommendation required: Cefotaxime, Ciprofloxacin, Co-amoxiclav,Daptomycin, Doripenem, etc.

Restricted:

Cefalxin, Ceftazdime, Cefuroxime,

Ciprofloxacin, Clindamycin, Meropenem, Sodiumfusidate, etc.

Unrestricted

: Amoxicillin, Benzylpencillin,

Clarithromycin, Erythromycin, etc.

HOW

BACTERIA MAY ACQUIRE

RESISTANCE

Spontaneousmutation

One in onehundred million

Inherent resistance

Gene transfer

MECHANISMS

There are threemechanisms ofantibacterial resistance

Enzymatic degradationof antibiotics

Alteration of bacterialproteins that areantimicrobial targets

Changes in membranepermeability toantibiotics

MISUSE OF ANTIBIOTIC DRUGS

Patients not following their prescriptions

Doctors prescribing antibiotics empirically

Over-the-counter availability of antibiotics withoutprofessional advice

Over and unnecessary prescription of antibiotics

More

than 50 million unnecessary antibiotic prescriptions are written

each year for patients, according to estimates by the CDC in 1998

INACCURATE DIAGNOSTICS

The use of incomplete or imperfect information todiagnose patients

In rich countries like Canada, an estimated 50% ofantibiotic prescriptions are given inappropriately

In developing countries, people rely on antibioticspurchased over the counter to make up for the absenceof medical advice

New development of rapid diagnostic techniques toreduce wait time for results

HOSPITALS

Hospitals are breeding grounds for antibioticresistant bacteria

Between 40-91% of antibiotics were prescribedinappropriately

A high percentage of hospital acquired infectionsare caused by highly resistant bacteria

Heavier use of antibiotics on sick patients canincrease selection for antibiotic resistant bacteria

GLOBALIZATION OF

ANTIBIOTIC RESISTANCE

Population mobility is the main factor in distributionof antibiotic resistant organisms

Globalization of trade and increased contributionof developing countries

Beware of patterns of resistance in differentcountries

China has the highest level of antibiotic resistance,followed by Kuwait and the US

WHAT IS CANADA'S ROLE?

Public Health Agency of Canada (PHAC),along with other governmental organizations: •

Policies

Research

Surveillance

Education