Antibacterial drugs | Quizlet

List characteristics of bacteria

small prokaryotic cells

• cell wall, cell membrane & capsule → structural support and protective role

• flagella → structure used for locomotion

• simple internal structure

Give 3 examples of gram positive bacteria

Staphylococcus

Streptococcus

Bacillus

Give 3 examples of gram negative bacteria

Helicobacter pylori

Acinetobacter

Klebsiella

Functions of intestinal microflora

maintain intestinal epithelium

• play a role in fiber digestion

• synthesize vitamin K, B1, B12, folic acid, and biotin

• resist harmful pathogens

Give 3 examples of probiotics

Lactobacillus

Bacillus

Enterococcus

List functions of probiotics

• provide protection against enteric pathogens

• improve gut barrier function

• stimulate, modulate, and regulate the host's immune response

List functions of probiotics + prebiotics

Support urogenital health

Anti-pathogenic activity Angiogenic activity Help regulate weight Support blood sugar control

Help reduce allergies May reduce cancer risk Reduce inflammation Support vitamin B synthesis Improved lactose metabolism and digestion of food

When does bacterial infection starts?

When pathogenic bacteria overcome the cutaneous or mucosal barriers and penetrate into body tissues,

What is the chain of infection

Bacteria/virus/parasite

reservoir

portal of exit

transmission

portal of entry

Susceptible host

What are the types of defense mechanisms

natural barriers

nonspecific immune responses

specific immune responses

What are natural barriers

• skin

• mucous membranes

• airway filters in respiratory tract

• acid pH of the stomach

• lysozyme in tears and saliva

• normal microbiota

What are nonspecific immune responses

• phagocytic cells (e.g. macrophages)

• cytokines

• NK cells

What are specific immune responses

• antibodies

• lymphocytes

Give 3 examples of 3 bacterial ilnesses

Strep throat Whooping cough Urinary tract infection

Is bacterial infection often localized?

yes

Do antibiotics work for bacterial illnesses

yes

Give 3 examples of 3 viral illnesses

Runny nose & cold

Sore throat

Flu

Is viral infection often systemic infection?

yes

Do antibiotics work for viral illnesses

no

Give 3 examples of viral or bacterial illnesses

Sinus infection

Ear infection

Bronchitis

Are viral/bacterial infections diffused?

yes

Do antibiotics work for bacterial/viral infections?

Maybe

List bactericidal (kill the bacteria) antibiotics

Aminoglycosides β-lactams

Vancomycin Quinolones Metronidazole

List bacteriostatic (stop bacterial growth) antibiotics

Chloramphenicol Erythromycin Clindamycin Sulfonamides Tetracyclines

What are the effects of bacterial resistance

alteration of drug binding site

alteration of membrane permeability degradation enzymes conformational change of drug & its inactivation

efflux pumps

Describe Resistance to β-lactams

β-lactamases or the production of altered penicillinbinding proteins or altered cell-wall permeability

Describe resistance to aminoglycosides

enzymes that acetylate, adenylate, or phosphorylate aminoglycosides that inhibit binding to ribosomes

Describe Resistance to tetracycline

plasmids causing efflux of the agent from the cytoplasm

Describe Resistance to macrolide

altered 23S ribosomal component of the 50S ribosome

Describe Resistance to sulfonamide and trimethoprim

altered synthetase and reductase enzymes

Describe Resistance to fluoroquinolones

altered DNA gyrase or cell-wall changes

What are the targets of antibacterial drugs

• inhibition of cell wall synthesis

• interference with cell membrane integrity

• inhibition of protein synthesis

• inhibition of nucleic acid synthesis

• inhibition of metabolic pathways

What are the inhibitors of cell wall synthesis

penicillins cephalosporins

bacitracin

vancomycin

What are penicilins used for

to treat staphylococcal and streptococcal bacterial infections

What is penicilin G used for

• rapid renal elimination • duration of action can be prolonged by: use of higher doses, combination with probenecid, intramuscular administration in depot form

What are the factors that limit the therapeutic usefulness of penicillin G

narrow antibacterial spectrum

inactivation by gastric acid (need for parenteral administration) resistance of staphylococcal strains that produce β-lactamase enzymes

Amoxicillin indications

skin infections urinary tract infections ear infections upper and lower respiratory infections pharyngitis tonsillitis endocarditis Helicobacter pylori infection

With what group of drugs is amoxicillin administered. Give examples of drugs

with β-lactamase inhibitor

clavulanic acid sulbactam

Amoxicillin SE

• hypersensitivity (from skin eruptions to anaphylactic shock)

• diarrhea

• nausea, vomiting

• pseudomembranous intestinal infection

• vaginal itching or discharge

• neurotoxic effects - mostly convulsions

• hematological disorders

Examples of cephalosporins

cefalexin

ceftriaxone

Cehalosporins characteristics

• β-lactam antibiotics

• inhibition of transpeptidase → bactericidal action

• acid-stable, but many are poorly absorbed

• mostly administered parenterally

• broad antibacterial spectrum

• mostly well tolerated

Against what are bacitracin and vanocomycin active?

only against Gram-positive bacteria

Why is bacitracin used only topically?

Because it is markedly nephrotoxic

For what disease is vanocomycin a first drug of choice

for the treatment of bowel inflammations occurring as complication of antibiotic therapy

What are the risks that increase after systemic administration of vanocomycin?

the risk of nephrotoxicity, ototoxicity or vestibular toxicity

What are two drug groups acting as inhibitors of tetrahydrofolate synthesis

Sulfonamides

Trimethoprim

Sulfonamides examples

Sulfamethoxazole Sulfapyridine

What are sulfonamides characteristics

• structurally resemble p-aminobenzoic acid and as false substrates competitively inhibit the utilization of p-aminobenzoic acid and dihydrofolate synthesis • bacteriostatic activity against a broad spectrum of pathogens • chemically synthesized

Why are sulfonamides used rarely?

due to the frequent emergence of resistant bacteria

Sulfonamides SE

• hypersensitivity reactions (rashes, erythema multiforme of the Stevens-Johnson type, exfoliative dermatitis)

• photosensitivity

• effects on the hematopoietic system (hemolytic anemia, agranulocytosis and aplastic anemia)

• crystalluria

• anorexia

• nausea

• vomiting

• headache

Trimethoprim characteristics

• inhibits bacterial dihydrofolate reductase • bacteriostatic activity against a broad spectrum of pathogens

In what is trimethoprim used in the most?

as a component of co-trimoxazole

co-trimoxazole = trimethoprim + sulfomethoxazole

What is sulfasalazine made of?

sulfapyridine + mesalazine

What is sulfasalazine used for?

• originally developed as an anti-rheumatic agent • used mainly in the treatment of inflammatory bowel disease