Antibacterial Antibacterial and Antiviral and Antiviral

DrugsDrugsLarry J. SchefflerLarry J. Scheffler

Lincoln High SchoolLincoln High School

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AntibacterialsAntibacterials

BacteriaBacteria DefinitionDefinition ReplicationReplication ShapesShapes DiseasesDiseases

AntibacterialsAntibacterials PenicillinPenicillin1.1. Discovery ofDiscovery of

2.2. SynthesisSynthesis

3.3. StructureStructure

4.4. Ways it functions Ways it functions General General

AntibacterialsAntibacterials1.1. ProblemsProblems

2.2. Possible solutionsPossible solutions2

Characteristics of Characteristics of BacteriaBacteria

Single celled or Single celled or non- cellular non- cellular

Spherical,spiral Spherical,spiral or rod–shaped or rod–shaped organismsorganisms

Lack chlorophyll Lack chlorophyll Reproduce by Reproduce by

fission fission Important as Important as

pathogens and pathogens and for biochemical for biochemical properties. properties.

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Infectious BacteriaInfectious Bacteria Cocci – Cocci – SphericialSphericial Often cause sore throats Often cause sore throats

and pneumoniaand pneumonia

Bacilli – Bacilli – Rod shapedRod shaped Mycolbacterium causeMycolbacterium cause

tuberculosistuberculosis

Spirochete – Spirochete – Spiral Spiral shapedshaped

Syphilis, gum infectionsSyphilis, gum infections

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Structure of a Structure of a BacteriumBacterium

CapsuleCapsule – – Protective layer of Protective layer of bacteria. made of proteins, sugars, bacteria. made of proteins, sugars, and lipidsand lipids

Cell wallCell wall – Provides the bacteria – Provides the bacteria with its shape and structure.with its shape and structure.

Cell membraneCell membrane – permeable – permeable membrane that transfers nutrients membrane that transfers nutrients and chemicals in and out of the cell.and chemicals in and out of the cell.

CytoplasmCytoplasm – Liquid within the cell – Liquid within the cell which serves to protect cell parts as which serves to protect cell parts as well as move materials throughout well as move materials throughout the cell. Contains glycogen, lipids the cell. Contains glycogen, lipids and other nutrientsand other nutrients

RibosomesRibosomes – synthesizes proteins. – synthesizes proteins. DNADNA – Single chromosome controls – Single chromosome controls

the functions of the cell. the functions of the cell. FlagellaFlagella – A tail-like appendage – A tail-like appendage

used for movement. used for movement. PilusPilus – Small hairs whose purpose – Small hairs whose purpose

is to stick to surfaces. Can also be is to stick to surfaces. Can also be used in reproduction.used in reproduction.

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Structure a BacteriumStructure a Bacterium Bacteria can be either Bacteria can be either

aerobic or anaerobicaerobic or anaerobic

Aerobic:-- require Aerobic:-- require oxygen for metabolism. oxygen for metabolism. They are more likely to They are more likely to infect surface areas infect surface areas such as the skin and the such as the skin and the respiratory tract.respiratory tract.

Anaerobic – multiply in Anaerobic – multiply in oxygen free and in low oxygen free and in low oxygen surroundings oxygen surroundings such as the intestines.such as the intestines.

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Replication by Binary FissionReplication by Binary FissionOne cell is split into two separate cells.One cell is split into two separate cells.

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Bacterial Caused Bacterial Caused DiseasesDiseases

AnthraxAnthrax CholeraCholera PlaguePlague Q-FeverQ-Fever Strep ThroatStrep Throat Staph Staph

InfectionsInfections TuberculosisTuberculosis

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The Discovery of PenicillinThe Discovery of Penicillin Penicillin was discovered in 1929 by Penicillin was discovered in 1929 by

scientist Alexander Fleming.scientist Alexander Fleming. He left for vacation with an agar He left for vacation with an agar

plate covered with the bacteria plate covered with the bacteria Staphylococcus aureusStaphylococcus aureus. .

When he returned he noticed that When he returned he noticed that the fungus, Penicillium, had grown the fungus, Penicillium, had grown on the plateon the plate

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The bacteria colony The bacteria colony surrounding the fungus had surrounding the fungus had become transparent because become transparent because the bacterial cells had the bacterial cells had undergone lysis.undergone lysis.

Development of Development of PenicillinPenicillin

Several years later Howard Florey and Several years later Howard Florey and E.B. Chain stumbled across Fleming’s E.B. Chain stumbled across Fleming’s research papers and were intrigued by research papers and were intrigued by his findings. his findings.

They were convinced that Flemming’s They were convinced that Flemming’s discovery could save a lot of lives, discovery could save a lot of lives, prevent pain, and make it much easier prevent pain, and make it much easier to fight infectious diseases and prevent to fight infectious diseases and prevent other infections.other infections.

They developed a way to mass produce They developed a way to mass produce penicillin making it available to soldiers penicillin making it available to soldiers wounded in world war II.wounded in world war II.

Florey and Chain were awarded the Florey and Chain were awarded the Nobel Prize in 1945 for their work on Nobel Prize in 1945 for their work on penicillin.penicillin. 10

Penicillin StructurePenicillin StructurePenicillins have a special structure that allows Penicillins have a special structure that allows them to interfere with the formation of the cell them to interfere with the formation of the cell wall when bacteria reproducewall when bacteria reproduce

The general structure of penicillinThe general structure of penicillin

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How Does it Function?How Does it Function? Penicillin prevents the cross linking of Penicillin prevents the cross linking of

small peptide chains in peptidoglycan, small peptide chains in peptidoglycan, which is the main polymer in bacterial which is the main polymer in bacterial cell walls. cell walls.

They do not affect bacteria which already They do not affect bacteria which already exist, rather Penicillin’s affect the exist, rather Penicillin’s affect the synthesis of new bacteria. synthesis of new bacteria.

The new bacteria grow without the ability The new bacteria grow without the ability to maintain cell rigidity, making them to maintain cell rigidity, making them susceptible to osmotic lysis.susceptible to osmotic lysis.

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The Action of The Action of PenicillinsPenicillinsThe The amide groupamide group in the in the

beta lactam is more beta lactam is more reactive due to the reactive due to the strained ring.strained ring.

The structure of the beta The structure of the beta lactam is similar to the lactam is similar to the structures of structures of cysteinecysteine and and valine.valine.

The beta lactam binds to The beta lactam binds to the enzyme that the enzyme that synthesizes the cell wall synthesizes the cell wall in bacteria, blocking its in bacteria, blocking its action.action.

As a result the bacteria As a result the bacteria rupture and break and rupture and break and cannot reproduce.cannot reproduce.

Note the similarities in structureto the beta lactam.

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Bacterial Immunity to Bacterial Immunity to PenicillinPenicillin

Antibiotic ResistanceAntibiotic Resistance – – Mutated bacteria which are Mutated bacteria which are immune to antibiotics are immune to antibiotics are more likely to survive when more likely to survive when excessive antibacterials are excessive antibacterials are used.used.

Bacteria develop enzymes Bacteria develop enzymes known as known as penicillinasespenicillinases that that destroy or render penicillin destroy or render penicillin ineffective.ineffective.

New antibiotics are New antibiotics are developed by developed by changing the Rchanging the R group side chain. group side chain.

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Structure of PenicillinStructure of Penicillin

Penicillin is a group of compounds which all contain the Penicillin is a group of compounds which all contain the same basic ring structure, known as beta-lactam. It is same basic ring structure, known as beta-lactam. It is comprised of two amino-acids (valine and cyteine) comprised of two amino-acids (valine and cyteine) through a tripeptide intermediate. The third amino acid through a tripeptide intermediate. The third amino acid (the R group) is replaced by another group, which (the R group) is replaced by another group, which gives different characteristics to differing penicillins.gives different characteristics to differing penicillins. 15

Narrow Range and Broad Narrow Range and Broad Range AntibioticsRange Antibiotics

Narrow range antibiotics target specificNarrow range antibiotics target specific kinds of bacteria. They are usually more potent. kinds of bacteria. They are usually more potent. Broad range antibiotics are effective against a wide Broad range antibiotics are effective against a wide

range of bacteria.range of bacteria. When doctors diagnose patients suspected of having When doctors diagnose patients suspected of having

bacterial infections, they must first take samples of bacterial infections, they must first take samples of body fluids, and try to determine the precise type of body fluids, and try to determine the precise type of infection.infection.

A broad range antibiotic might be prescribed initially. A broad range antibiotic might be prescribed initially. Once a bacterial infection is properly diagnosed it may Once a bacterial infection is properly diagnosed it may be appropriate to switch to a narrow range antibioticbe appropriate to switch to a narrow range antibiotic..

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Overuse of PenicillinOveruse of Penicillin

Leads to greater immunity of Leads to greater immunity of bacteria to penicillin, since the bacteria to penicillin, since the strongest and most resistant strains strongest and most resistant strains survive.survive.

Greater doses of penicillin are Greater doses of penicillin are required to be effectiverequired to be effective

Danger of developing super bacteriaDanger of developing super bacteria Kill beneficial bacteria as well as Kill beneficial bacteria as well as

harmful bacteriaharmful bacteria

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Penicillin SynthesisPenicillin Synthesis

A sterilized growth A sterilized growth medium and an medium and an inoculum of strongly inoculum of strongly growing hyphae is growing hyphae is added to stainless added to stainless steel fermenters. steel fermenters. The fermenters The fermenters stirred continuously stirred continuously and glucose, nitrate and glucose, nitrate and sterile air are and sterile air are periodically added. periodically added.

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Antibacterial PhagesAntibacterial Phages

These can replace antibacterial These can replace antibacterial drugs such as penicillin by drugs such as penicillin by utilizing viruses which infect utilizing viruses which infect bacterial cells which causes bacterial cells which causes them to lyse, releasing more of them to lyse, releasing more of the destructive phages.the destructive phages.

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AntiviralsAntivirals

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AntiviralsAntivirals

VirusesViruses DefinitionDefinition ReplicationReplication

AIDSAIDS AIDS DefinitionAIDS Definition History of AIDSHistory of AIDS Ways it can Ways it can

spreadspread TreatmentTreatment

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Virus CharacteristicsVirus Characteristics A virus is an infectious agent found in A virus is an infectious agent found in

virtually all life forms.virtually all life forms. Viruses consist of genetic material, Viruses consist of genetic material,

and have a central core either DNA and have a central core either DNA nor RNAnor RNA

Although they are infectious agents, Although they are infectious agents, they differ from bacteria in that they they differ from bacteria in that they contain contain no nucleus or cytoplasm.no nucleus or cytoplasm.

They do not feed, excrete, or growThey do not feed, excrete, or grow They cannot reproduce outside of a They cannot reproduce outside of a

living cell.living cell.

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Virus StructureVirus Structure There are many There are many

types of virus with types of virus with varying shape and varying shape and structure.structure.

All virus have a All virus have a central core of central core of either DNA or RNA either DNA or RNA surrounded by a surrounded by a coat of regularly coat of regularly packed protein packed protein units.units.

No nucleus or No nucleus or cytoplasm like cytoplasm like bacteria.bacteria.

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Diagram of an AIDS Virus

Virus ReplicationVirus Replication The replication of viruses can only occur if the The replication of viruses can only occur if the

virus has virus has attached and penetratedattached and penetrated the living host the living host cell.cell.

It injects it’s DNA or RNA into the host cell’s It injects it’s DNA or RNA into the host cell’s cytoplasm. cytoplasm.

It takes over the replication mechanism of the It takes over the replication mechanism of the host cell.host cell.

This causes the cell to die or to be altered, which This causes the cell to die or to be altered, which results in the symptoms of a viral infection. results in the symptoms of a viral infection.

The host cell produces new viral DNA or RNA The host cell produces new viral DNA or RNA cells which are then released to affect other cells which are then released to affect other healthy cells. healthy cells.

A virus that contains RNA rather than DNA is A virus that contains RNA rather than DNA is called a retrovirus.called a retrovirus.

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Virus ReplicationVirus Replication

The virus uses the cell mechanism to replicate itselfThe virus uses the cell mechanism to replicate itself 25

AIDS a Viral Transmitted AIDS a Viral Transmitted DiseaseDisease

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A 10-year study completed in A 10-year study completed in 2005 found a strain of Simian 2005 found a strain of Simian Immunodeficiency Virus (SIV) Immunodeficiency Virus (SIV) in a number of chimpanzee in a number of chimpanzee colonies in south-eastern colonies in south-eastern Cameroon that was a viral Cameroon that was a viral ancestor of the HIV-1 that ancestor of the HIV-1 that causes AIDS in humans.     causes AIDS in humans.    

In 1981 AIDS was first In 1981 AIDS was first identified within homosexual identified within homosexual men men

AIDS in the USAIDS in the US

940,000 cases of AIDS were reported in 940,000 cases of AIDS were reported in the United States from 1981 through the United States from 1981 through 2004. 2004.

In 2004, about 39,000 new cases of HIV In 2004, about 39,000 new cases of HIV infection were reported. infection were reported.

Currently, there are approximately 1.1 Currently, there are approximately 1.1 million people in the United States who million people in the United States who are infected with the human are infected with the human immunodeficiency virus. immunodeficiency virus.

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History of AIDS in Africa History of AIDS in Africa Wide spread in Africa.Wide spread in Africa. Lack of access to Lack of access to

education.education. Reticence of some Reticence of some

leaders to recognize leaders to recognize the problem.the problem.

Lack of access to Lack of access to treatment.treatment.

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AIDS DefinitionAIDS Definition AIDS ( Acquired AIDS ( Acquired

Immune Immune Deficiency Deficiency Syndrome) is Syndrome) is caused by a caused by a retrovirus that retrovirus that contains RNA contains RNA rather then DNA.rather then DNA.

This specific virus This specific virus invades particular invades particular cells, that are cells, that are within the immune within the immune system making system making the body unable to the body unable to fight off infections. fight off infections.

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AIDS DefinitionAIDS Definition The human The human

immunodeficiency virus immunodeficiency virus (HIV), which causes (HIV), which causes acquired immunodeficiency acquired immunodeficiency syndrome (AIDS), syndrome (AIDS), principally attacks principally attacks T-4 T-4 lymphocytes,lymphocytes, a vital part of a vital part of the human immune system.the human immune system.

As a result, the ability of As a result, the ability of the body to resist the body to resist opportunistic viral, opportunistic viral, bacterial, fungal, protozoal, bacterial, fungal, protozoal, and other infections is and other infections is greatly weakened. greatly weakened.

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3 Ways AIDS can be 3 Ways AIDS can be spreadspread

Scientists have identified three ways Scientists have identified three ways that HIV infections spread:that HIV infections spread:

1.1. Sexual intercourse with an infected Sexual intercourse with an infected person, person,

2.2. Contact with contaminated blood,Contact with contaminated blood,

3.3. Transmission from an infected Transmission from an infected mother to her child before or during mother to her child before or during birth or through breastfeeding.birth or through breastfeeding.

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AIDS Diagnosis and AIDS Diagnosis and TreatmentTreatment While no medical treatment cures AIDS, While no medical treatment cures AIDS,

there are many drugs that have recently there are many drugs that have recently been developed to eradicate the HIV virus.been developed to eradicate the HIV virus.

Full blown symptoms of AIDS may not Full blown symptoms of AIDS may not appear for more then 10 years.appear for more then 10 years.

It usually takes 2-3 months after the initial It usually takes 2-3 months after the initial infection for a person to test positive for HIVinfection for a person to test positive for HIV

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AIDS Diagnosis and AIDS Diagnosis and TreatmentTreatment While no medical treatment cures AIDS, While no medical treatment cures AIDS,

there are many drugs that have recently there are many drugs that have recently been developed to eradicate the HIV virus.been developed to eradicate the HIV virus.

Although full blown symptoms of AIDS may Although full blown symptoms of AIDS may not appear for more then 10 years.not appear for more then 10 years.

It usually takes 2-3 months after the initial It usually takes 2-3 months after the initial infection for a person to test positive for HIVinfection for a person to test positive for HIV

During this time frame a person inflected During this time frame a person inflected with HIV can easily spread the virus without with HIV can easily spread the virus without realizing it.realizing it.

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Antiviral DrugsAntiviral Drugs Common viral infections such as the Common viral infections such as the

influenza, mumps, or chicken pox are influenza, mumps, or chicken pox are usually overcome by the body’s immune usually overcome by the body’s immune system.system.

Vaccines are often used to build up Vaccines are often used to build up immunity before a viral inflection occurs.immunity before a viral inflection occurs.

Medications for viral diseases are used to:Medications for viral diseases are used to:1.1. relieve associated pain, relieve associated pain, 2.2. reduce fever, orreduce fever, or3.3. counteract secondary inflectionscounteract secondary inflections

Rapid replication of viruses makes it Rapid replication of viruses makes it difficult to develop effective antiviral drugs. difficult to develop effective antiviral drugs. The viruses are often very high even The viruses are often very high even before the first symptoms appear.before the first symptoms appear.

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Antiviral DrugsAntiviral Drugs Only a few effective antiviral drugs Only a few effective antiviral drugs

have been developed.have been developed. Antiviral drugs work byAntiviral drugs work by

1.1. Altering the cell’s genetic material so that Altering the cell’s genetic material so that the virus cannot use it to multiply, i.e. the virus cannot use it to multiply, i.e. acycloviracyclovir

2.2. Preventing new virus formed from leaving Preventing new virus formed from leaving the cell, i.e. amatadinethe cell, i.e. amatadine

Viruses mutate frequently leaving the Viruses mutate frequently leaving the antiviral drug ineffectiveantiviral drug ineffective

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Antiviral Drugs - AcyclovirAntiviral Drugs - Acyclovir

Acyclovir is Acyclovir is an antiviral an antiviral drug used to drug used to treat treat Herpes Herpes SimplexSimplex

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Acyclovir has a structure similar to deoxyguanosine, one of the building blocks of DNA. It tricks the viral enzyme DNA polymerase into incorporating it into its DNA instead of guanine making it impossible to replicate.

Antiviral Drugs - AZTAntiviral Drugs - AZT

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AZT combines with the enzyme that the HIV virus uses to build DNA from RNA and clogs up its active site. It acts as a reverse transcriptase inhibitor. Since only Retro-Viruses, such as HIV, use this enzyme, AZT does not affect normal cells. Unfortunately it causes anaemia

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AZT was the first AZT was the first antiviral drug used to antiviral drug used to effectively treat HIV-AIDSeffectively treat HIV-AIDS

Other HIV Antiviral DrugsOther HIV Antiviral DrugsMore recentlyMore recentlyddI and ddC ddI and ddC have been have been developed for developed for HIV treatment.HIV treatment.

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While antiviral drugs show promise in preventing AIDS in people who are HIV positive, these drugs are still very expensive and not available to many people who are HIV positive,

Other Antiviral DrugsOther Antiviral DrugsRecently, a series of nucleoside have been developed Recently, a series of nucleoside have been developed that appear to be effective against herpes virus.that appear to be effective against herpes virus.

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