11

Chapter 9Chapter 9Drugs for Bacterial, Drugs for Bacterial, Viral, and Fungal Viral, and Fungal InfectionsInfections

22

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

33

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

44

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

55

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

66

AntibioticsAntibiotics

Spectrum of ActivitySpectrum of Activity– Narrow spectrum Narrow spectrum – Broad spectrumBroad spectrum

77

Methods of ControlMethods of Control

BactericidalBactericidal– Kills bacteriaKills bacteria

BacteriostaticBacteriostatic– Prevents further replicationPrevents further replication

88

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

99

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.

1010

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

1111

Adverse effectsAdverse effects– Allergic reactionsAllergic reactions

Rash, itching, swelling, anaphylactic, Rash, itching, swelling, anaphylactic, disrupted GI functiondisrupted GI function

1212

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

1313

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

1414

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

1515

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

1616

Examples of Viral Examples of Viral InfectionsInfections Common ColdCommon Cold FluFlu HerpesHerpes WartsWarts MononucleosisMononucleosis HepatitisHepatitis HIVHIV

1717

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

1818

Table 9-2: Examples of Table 9-2: Examples of Prescription Antiviral Prescription Antiviral MedicationsMedications

1919

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

2020

Table 9-3: Vaccines Table 9-3: Vaccines

2121

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

2222

Tinea InfectionsTinea Infections

CapitisCapitis – ScalpScalp

CorporisCorporis – TrunkTrunk

CrurisCruris – ““Jock itch” Jock itch”

PedisPedis – Athlete’s foot Athlete’s foot

OnychomycosisOnychomycosis– NailsNails

2323

Tinea Infections (Tinea Infections (cont.cont.))

Community showers Community showers Direct contactDirect contact Length of infection increases Length of infection increases

problemsproblems

2424

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

2525

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

2626

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

2727

What to Tell the What to Tell the Athlete Athlete Page 129Page 129