Post on 15-Dec-2015
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Chapter 9Chapter 9Drugs for Bacterial, Drugs for Bacterial, Viral, and Fungal Viral, and Fungal InfectionsInfections
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When the body’s immune system When the body’s immune system is unable to combat and control is unable to combat and control an invasion by a microorganism, an invasion by a microorganism, it requires assistanceit requires assistance
ChemotherapeuticsChemotherapeutics– Fight organisms such as bacteria, Fight organisms such as bacteria,
viruses, fungiviruses, fungi– Control or eliminate infectionControl or eliminate infection
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AntibioticsAntibiotics
BacteriaBacteria Unicellular microorganismsUnicellular microorganisms Can synthesize proteins and carry Can synthesize proteins and carry
out cellular metabolism, but they out cellular metabolism, but they need nourishment for these need nourishment for these activities from the hostactivities from the host
Some bacteria are beneficialSome bacteria are beneficial
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BacteriaBacteria
Bacteria that exist in the Bacteria that exist in the gastrointestinal system are gastrointestinal system are helpful to their human hosthelpful to their human host– Assist in the digestion of foodsAssist in the digestion of foods– Limit the growth of other Limit the growth of other
microorganismsmicroorganisms– Limit excess production of some Limit excess production of some
stomach acidsstomach acids
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Types of AntibioticsTypes of Antibiotics
Bacterial infections must be Bacterial infections must be diagnosed and treated by a diagnosed and treated by a physicianphysician
Variety of classification systemsVariety of classification systems Two in this book:Two in this book:
– Spectrum of ActivitySpectrum of Activity– Method of ControlMethod of Control
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AntibioticsAntibiotics
Spectrum of ActivitySpectrum of Activity– Narrow spectrum Narrow spectrum – Broad spectrumBroad spectrum
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Methods of ControlMethods of Control
BactericidalBactericidal– Kills bacteriaKills bacteria
BacteriostaticBacteriostatic– Prevents further replicationPrevents further replication
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Basic Mechanisms of Basic Mechanisms of Antibacterial DrugsAntibacterial Drugs Must be selectively toxic without Must be selectively toxic without
causing excessive damage to normal causing excessive damage to normal cellscells
Four primary mechanisms of action for Four primary mechanisms of action for antibacterial drugs:antibacterial drugs:– Inhibition of bacterial cell wall and functionInhibition of bacterial cell wall and function– Inhibition of protein synthesisInhibition of protein synthesis– Inhibition of DNA/RNA functionInhibition of DNA/RNA function– Inhibition of folic acid synthesisInhibition of folic acid synthesis
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PenicillinPenicillin
Discovered in 1928 (Alexander Fleming’s Discovered in 1928 (Alexander Fleming’s laboratory), where mold was mistakenly laboratory), where mold was mistakenly introduced to bacteria being grown.introduced to bacteria being grown.
Initially, the scientist was going to discard Initially, the scientist was going to discard the contaminated Petri dish but noticed the contaminated Petri dish but noticed that the bacteria in the dish were dying that the bacteria in the dish were dying around this contaminated area. around this contaminated area.
Drug company in the United States Drug company in the United States decided to start making it and later decided to start making it and later discovered ways to produce penicillin in discovered ways to produce penicillin in the laboratory.the laboratory.
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Inhibits specific enzymes that allow Inhibits specific enzymes that allow construction of bacteria’s cell wallconstruction of bacteria’s cell wall
Is effective in selectively destroying Is effective in selectively destroying bacteria without affecting host cellsbacteria without affecting host cells
Oral and injectableOral and injectable Treat ear infections, pneumonia, Treat ear infections, pneumonia,
skin infectionsskin infections
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Adverse effectsAdverse effects– Allergic reactionsAllergic reactions
Rash, itching, swelling, anaphylactic, Rash, itching, swelling, anaphylactic, disrupted GI functiondisrupted GI function
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Adverse Effects of Adverse Effects of AntibioticsAntibiotics
Hypersensitivity Hypersensitivity Diarrhea, GI distress, nausea/vomiting, Diarrhea, GI distress, nausea/vomiting,
itching, swelling, skin rashes, or itching, swelling, skin rashes, or difficulty breathingdifficulty breathing
In some, an anaphylactic reaction In some, an anaphylactic reaction resulting in severe bronchoconstriction resulting in severe bronchoconstriction and cardiovascular collapseand cardiovascular collapse
Some of the antibiotics may produce a Some of the antibiotics may produce a photosensitivity reactionphotosensitivity reaction
Birth control pill problemsBirth control pill problems
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Minor Skin InfectionsMinor Skin Infections
Triple antibiotic ointmentsTriple antibiotic ointments Topical application of multiple Topical application of multiple
antibiotic therapies to destroy antibiotic therapies to destroy any microbes that may exist on or any microbes that may exist on or around the infected area.around the infected area.– Inhibit cell wall activity, protein Inhibit cell wall activity, protein
synthesis, and/or DNA synthesissynthesis, and/or DNA synthesis Example: NeosporinExample: Neosporin
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Antibiotic ResistanceAntibiotic Resistance
Becoming more commonBecoming more common Strains of bacteria are developing Strains of bacteria are developing
resistance to certain antibacterial resistance to certain antibacterial drugsdrugs
Mutations due to taking only a portion Mutations due to taking only a portion of prescribed dosageof prescribed dosage
OverprescribingOverprescribing Researchers continually working to Researchers continually working to
develop new drugdevelop new drug
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Antiviral MedicationsAntiviral Medications
Virus holding DNA or RNA invades Virus holding DNA or RNA invades the body via airborne or opening the body via airborne or opening in skinin skin
Finds host cell and replicatesFinds host cell and replicates Ranges from benign to fatalRanges from benign to fatal
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Examples of Viral Examples of Viral InfectionsInfections Common ColdCommon Cold FluFlu HerpesHerpes WartsWarts MononucleosisMononucleosis HepatitisHepatitis HIVHIV
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Oral MedicationsOral Medications
Inhibit viral DNA replicationInhibit viral DNA replication Table 9-2, pg 127Table 9-2, pg 127 The sooner the patient takes the The sooner the patient takes the
prescription medication, the prescription medication, the quicker the symptoms will quicker the symptoms will subsidesubside
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Table 9-2: Examples of Table 9-2: Examples of Prescription Antiviral Prescription Antiviral MedicationsMedications
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Viral VaccinesViral Vaccines
Entire or partial virus is Entire or partial virus is inactivated in lab setting so that inactivated in lab setting so that is cannot replicateis cannot replicate
Injected into human hostInjected into human host Body produces antibodies in Body produces antibodies in
preparation for a live viral invaderpreparation for a live viral invader
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Antifungal AgentsAntifungal Agents
Fungus – a plantlike microorganismFungus – a plantlike microorganism– Exist in air or soilExist in air or soil
Opportunistic and occur on epidermisOpportunistic and occur on epidermis To develop, multiply, and sustain lifeTo develop, multiply, and sustain life
– Warmth, darkness, moistureWarmth, darkness, moisture Proper hygiene can reduce possibility Proper hygiene can reduce possibility
of fungal infectionsof fungal infections
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Tinea InfectionsTinea Infections
CapitisCapitis – ScalpScalp
CorporisCorporis – TrunkTrunk
CrurisCruris – ““Jock itch” Jock itch”
PedisPedis – Athlete’s foot Athlete’s foot
OnychomycosisOnychomycosis– NailsNails
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Tinea Infections (Tinea Infections (cont.cont.))
Community showers Community showers Direct contactDirect contact Length of infection increases Length of infection increases
problemsproblems
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Fungal InfectionsFungal Infections
Some find way into body and Some find way into body and multiplymultiply
Due to inadequate care of Due to inadequate care of cutaneous infectioncutaneous infection
Or when fungal spores become Or when fungal spores become airborne and are inhaledairborne and are inhaled
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Oral and Topical Oral and Topical MedicationsMedications OTC used first, prescriptions can OTC used first, prescriptions can
be prescribed by physicianbe prescribed by physician 1 week to 1+ months to 1 week to 1+ months to
completely control infectioncompletely control infection Meds impair cell membrane Meds impair cell membrane
synthesis, cell cannot function synthesis, cell cannot function normally and dies normally and dies
Table 9-4, pg 128Table 9-4, pg 128
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Adverse Effects of Adverse Effects of Antifungal AgentsAntifungal Agents Very safe, few side effectsVery safe, few side effects Allergic reactionsAllergic reactions Observe area being treatedObserve area being treated