1 Chapter 9 Drugs for Bacterial, Viral, and Fungal Infections

2 When the body’s immune system is unable to combat and control an invasion by a microorganism, it requires assistance When the body’s immune system is unable to combat and control an invasion by a microorganism, it requires assistance Chemotherapeutics Chemotherapeutics –Fight organisms such as bacteria, viruses, fungi –Control or eliminate infection

3 Antibiotics Bacteria Bacteria Unicellular microorganisms Unicellular microorganisms Can synthesize proteins and carry out cellular metabolism, but they need nourishment for these activities from the host Can synthesize proteins and carry out cellular metabolism, but they need nourishment for these activities from the host Some bacteria are beneficial Some bacteria are beneficial

4 Bacteria Bacteria that exist in the gastrointestinal system are helpful to their human host Bacteria that exist in the gastrointestinal system are helpful to their human host –Assist in the digestion of foods –Limit the growth of other microorganisms –Limit excess production of some stomach acids

5 Types of Antibiotics Bacterial infections must be diagnosed and treated by a physician Bacterial infections must be diagnosed and treated by a physician Variety of classification systems Variety of classification systems Two in this book: Two in this book: –Spectrum of Activity –Method of Control

6 Antibiotics Spectrum of Activity Spectrum of Activity –Narrow spectrum –Broad spectrum

7 Methods of Control Bactericidal Bactericidal –Kills bacteria Bacteriostatic Bacteriostatic –Prevents further replication

8 Basic Mechanisms of Antibacterial Drugs Must be selectively toxic without causing excessive damage to normal cells Must be selectively toxic without causing excessive damage to normal cells Four primary mechanisms of action for antibacterial drugs: Four primary mechanisms of action for antibacterial drugs: –Inhibition of bacterial cell wall and function –Inhibition of protein synthesis –Inhibition of DNA/RNA function –Inhibition of folic acid synthesis

9 Penicillin Discovered in 1928 (Alexander Fleming’s laboratory), where mold was mistakenly introduced to bacteria being grown. Discovered in 1928 (Alexander Fleming’s laboratory), where mold was mistakenly introduced to bacteria being grown. Initially, the scientist was going to discard the contaminated Petri dish but noticed that the bacteria in the dish were dying around this contaminated area. Initially, the scientist was going to discard the contaminated Petri dish but noticed that the bacteria in the dish were dying around this contaminated area. Drug company in the United States decided to start making it and later discovered ways to produce penicillin in the laboratory. Drug company in the United States decided to start making it and later discovered ways to produce penicillin in the laboratory.

10 Inhibits specific enzymes that allow construction of bacteria’s cell wall Inhibits specific enzymes that allow construction of bacteria’s cell wall Is effective in selectively destroying bacteria without affecting host cells Is effective in selectively destroying bacteria without affecting host cells Oral and injectable Oral and injectable Treat ear infections, pneumonia, skin infections Treat ear infections, pneumonia, skin infections

11 Adverse effects Adverse effects –Allergic reactions Rash, itching, swelling, anaphylactic, disrupted GI function Rash, itching, swelling, anaphylactic, disrupted GI function

12 Adverse Effects of Antibiotics Hypersensitivity Hypersensitivity Diarrhea, GI distress, nausea/vomiting, itching, swelling, skin rashes, or difficulty breathing Diarrhea, GI distress, nausea/vomiting, itching, swelling, skin rashes, or difficulty breathing In some, an anaphylactic reaction resulting in severe bronchoconstriction and cardiovascular collapse In some, an anaphylactic reaction resulting in severe bronchoconstriction and cardiovascular collapse Some of the antibiotics may produce a photosensitivity reaction Some of the antibiotics may produce a photosensitivity reaction Birth control pill problems Birth control pill problems

13 Minor Skin Infections Triple antibiotic ointments Triple antibiotic ointments Topical application of multiple antibiotic therapies to destroy any microbes that may exist on or around the infected area. Topical application of multiple antibiotic therapies to destroy any microbes that may exist on or around the infected area. –Inhibit cell wall activity, protein synthesis, and/or DNA synthesis Example: Neosporin Example: Neosporin

14 Antibiotic Resistance Becoming more common Becoming more common Strains of bacteria are developing resistance to certain antibacterial drugs Strains of bacteria are developing resistance to certain antibacterial drugs Mutations due to taking only a portion of prescribed dosage Mutations due to taking only a portion of prescribed dosage Overprescribing Overprescribing Researchers continually working to develop new drug Researchers continually working to develop new drug

15 Antiviral Medications Virus holding DNA or RNA invades the body via airborne or opening in skin Virus holding DNA or RNA invades the body via airborne or opening in skin Finds host cell and replicates Finds host cell and replicates Ranges from benign to fatal Ranges from benign to fatal

16 Examples of Viral Infections Common Cold Common Cold Flu Flu Herpes Herpes Warts Warts Mononucleosis Mononucleosis Hepatitis Hepatitis HIV HIV

17 Oral Medications Inhibit viral DNA replication Inhibit viral DNA replication Table 9-2, pg 127 Table 9-2, pg 127 The sooner the patient takes the prescription medication, the quicker the symptoms will subside The sooner the patient takes the prescription medication, the quicker the symptoms will subside

18 Table 9-2: Examples of Prescription Antiviral Medications

19 Viral Vaccines Entire or partial virus is inactivated in lab setting so that is cannot replicate Entire or partial virus is inactivated in lab setting so that is cannot replicate Injected into human host Injected into human host Body produces antibodies in preparation for a live viral invader Body produces antibodies in preparation for a live viral invader

20 Table 9-3: Vaccines

21 Antifungal Agents Fungus – a plantlike microorganism Fungus – a plantlike microorganism –Exist in air or soil Opportunistic and occur on epidermis Opportunistic and occur on epidermis To develop, multiply, and sustain life To develop, multiply, and sustain life –Warmth, darkness, moisture Proper hygiene can reduce possibility of fungal infections Proper hygiene can reduce possibility of fungal infections

22 Tinea Infections Capitis Capitis –Scalp Corporis Corporis –Trunk Cruris Cruris –“Jock itch” Pedis Pedis –Athlete’s foot Onychomycosis Onychomycosis –Nails

23 Tinea Infections (cont.) Community showers Community showers Direct contact Direct contact Length of infection increases problems Length of infection increases problems

24 Fungal Infections Some find way into body and multiply Some find way into body and multiply Due to inadequate care of cutaneous infection Due to inadequate care of cutaneous infection Or when fungal spores become airborne and are inhaled Or when fungal spores become airborne and are inhaled

25 Oral and Topical Medications OTC used first, prescriptions can be prescribed by physician OTC used first, prescriptions can be prescribed by physician 1 week to 1+ months to completely control infection 1 week to 1+ months to completely control infection Meds impair cell membrane synthesis, cell cannot function normally and dies Meds impair cell membrane synthesis, cell cannot function normally and dies Table 9-4, pg 128 Table 9-4, pg 128

26 Adverse Effects of Antifungal Agents Very safe, few side effects Very safe, few side effects Allergic reactions Allergic reactions Observe area being treated Observe area being treated

27 What to Tell the Athlete Page 129 Page 129