Antibacterial Antibacterial and Antiviral and Antiviral

DrugsDrugs

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AntibacterialsAntibacterials

BacteriaBacteriaDefinitionDefinition

ReplicationReplication

ShapesShapes

DiseasesDiseases

AntibacterialsAntibacterialsPenicillinPenicillin

1.1. Discovery ofDiscovery of

2.2. SynthesisSynthesis

3.3. StructureStructure

4.4. Ways it functions Ways it functions

General AntibacterialsGeneral Antibacterials1.1. ProblemsProblems

2.2. Possible solutionsPossible solutions

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Characteristics of BacteriaCharacteristics of Bacteria

Single celled or non- Single celled or non- cellular cellular Spherical,spiral or Spherical,spiral or rod–shaped rod–shaped organismsorganismsLack chlorophyll Lack chlorophyll Reproduce by fission Reproduce by fission Important as Important as pathogens and for pathogens and for biochemical 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 BacteriumStructure of a BacteriumCapsuleCapsule – – Protective layer of Protective layer of bacteria. made of proteins, sugars, bacteria. made of proteins, sugars, and lipidsand lipidsCell 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 nutrientsRibosomesRibosomes – 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. 5

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 Replication by Binary FissionFission

One 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 InfectionsStaph Infections

TuberculosisTuberculosis

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The Discovery of The Discovery of PenicillinPenicillinPenicillin 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 PenicillinPenicillinSeveral 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 PenicillinsThe Action of PenicillinsThe 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 same Penicillin is a group of compounds which all contain the same basic ring structure, known as beta-lactam. It is comprised of basic ring structure, known as beta-lactam. It is comprised of two amino-acids (valine and cyteine) through a tripeptide two amino-acids (valine and cyteine) through a tripeptide intermediate. The third amino acid (the R group) is replaced by intermediate. The third amino acid (the R group) is replaced by another group, which gives different characteristics to differing another group, which gives different characteristics to differing penicillins.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 bacteria to Leads to greater immunity of bacteria to penicillin, since the strongest and most penicillin, since the strongest and most resistant strains survive.resistant strains survive.Greater doses of penicillin are required to Greater doses of penicillin are required to be effectivebe effectiveDanger of developing super bacteriaDanger of developing super bacteriaKill beneficial bacteria as well as harmful Kill beneficial bacteria as well as harmful bacteriabacteria

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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. The steel fermenters. The fermenters stirred fermenters stirred continuously and continuously and glucose, nitrate and glucose, nitrate and sterile air are 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

VirusesVirusesDefinitionDefinition

ReplicationReplication

AIDSAIDSAIDS DefinitionAIDS Definition

History of AIDSHistory of AIDS

Ways it can spreadWays it can spread

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, and Viruses consist of genetic material, and have a central core either DNA nor RNAhave a central core either DNA nor RNAAlthough they are infectious agents, they Although they are infectious agents, they differ from bacteria in that they contain differ from bacteria in that they contain no no nucleus or cytoplasm.nucleus or cytoplasm.They do not feed, excrete, or growThey do not feed, excrete, or growThey cannot reproduce outside of a living They cannot reproduce outside of a living cell.cell.

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Virus StructureVirus Structure

There are many types There are many types of virus with varying of virus with varying shape and structure.shape and structure.

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

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

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Diagram of an AIDS Virus

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

This specific virus This specific virus invades particular invades particular cells, that are within cells, that are within the immune system the immune system making the body making the body unable to fight off unable to fight off infections. 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 HIVDuring 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 influenza, Common viral infections such as the influenza, mumps, or chicken pox are usually overcome mumps, or chicken pox are usually overcome by the body’s immune system.by the body’s immune system.Vaccines are often used to build up immunity Vaccines are often used to build up immunity before a viral inflection occurs.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 difficult to Rapid replication of viruses makes it difficult to develop effective antiviral drugs. The viruses develop effective antiviral drugs. The viruses are often very high even before the first are often very high even before the first symptoms appear.symptoms appear.

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Antiviral DrugsAntiviral Drugs

Only a few effective antiviral drugs have Only a few effective antiviral drugs have been developed.been developed.

Antiviral drugs work byAntiviral drugs work by1.1. Altering the cell’s genetic material so that the Altering the cell’s genetic material so that the

virus cannot use it to multiply, i.e. acyclovirvirus cannot use it to multiply, i.e. acyclovir

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

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

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Antiviral Drugs - Antiviral Drugs - AcyclovirAcyclovir

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

Other HIV Antiviral Other HIV Antiviral DrugsDrugs

More 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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