Antibiotics

Microbiology 3113 with Ortiz at University of Oklahoma

About this deck

By: Cassidy Bennett
Textbook:

Essential Cell Biology, Second Edition
Created: 2012-01-25
Size: 87 flashcards
Views: 6

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B-Lactams

Covalently bind penicillin-binding proteins in the cell membrane. Narrow, extended, or broad spectrum. May cause hypersensitivity reactions, CNS excitation, or seizures. Renally excreted through the urine. Most ionized at body pH - no PM penetration

Enzymes located in the cell membrane that are involved in cell wall synthesis

Penicillin binding proteins

Penicillin G

B-lactam. Penicillinase sensitive. Narrow spectrum (Gram +). May cause hypersensitivity rxns, CNS excitation seizures. Not acid-stable. IV or IM administration only. Hepatic and renal elimination (no need to reduce dosage for renal insufficiency)

Penicillin V

B-lactam. Penicillinase sensitive. Narrow spectrum (Gram +). May cause hypersensitivity rxns, CNS excitation, and seizures. Oral administration. Hepatic and renal elimination (no need to reduce dosage for renal insufficiency).

Ampicillin

B-lactam. Forms zwitterion at body pH so it can pass through the cell membrane. Make it easier to effect Gram negative cells. Extended spectrum. Can cause extensive, non-allergenic rash and mild diarrhea. IV administration.

Amoxicillin

B-lactam. Forms zwitterion at body pH so it can pass through the cell membrane. Makes it easier to effect Gram negative cells. Extended spectrum. Can cause ampicillin rash. Oral administration.

Piperacillin

B-lactam. Specific for Pseudomonas aeruginosa and other Gram negatives. Broad spectrum (broadest of all penicillins). IV administration.

Ampicillin Rash

Extensive rash that is non-allergenic caused by mono or drug interactions

B-lactamase inhibitors

Irreversible inhibitors of B-lactamases. Used only w/ penicillin.

Cephalosporins

Covalently binds penicillin binding proteins. Larger ring for more substitutions. Spectrum varies by generation. Can cause cross-allergic reactions w/ B-lactams, CNS effects, and alcohol intolerance. Renal excretion.

Cephalexin

First generation cephalosporin. Used for UTIs and wound infections. Extended spectrum. Oral administration. Cross-allergic rxns w/ B-lactams, CNS effects, and alcohol intolerance. Renal elimination Rapid half life.

Cefazolin

First generation cephalosporin. Used for UTIs and wound infections. Extended. Cross-allergic rxns w/ B-lactams, CNS effects, and alcohol intolerance. IV administration. Renal elimination.

Cefoxitin

Second generation cephalosporin. A cephamycin indicated for abdominal infections and surgical prophylaxis involving the abdomen. Extended spectrum w/ some anaerobic effect. Renal elimination.

Ceftriaxone

Third generation cephalosporin. Crosses BBB. Important for meningitis and Enterobacteriaceae. Resistant to most B-lactamase. Broad spectrum (Gram + is not as good as others). Excretion in bile.

Ceftazidime

Third generation cephalosporin. Crosses the BBB. Important for meningitis and Enterobacteriaceae. Esp. important for Pseudomonas aerugionsa. Broad spectrum (Gram + is not as good as others). Renal elimination.

Cefepime

Fourth generation cephalosporin. Resistant to most B-lactamases. Broad spectrum, better Gram + than 3rd generation. Renal elimination.

Ceftaroline

5th generation cephalosporin. Resistant to most B-lactamases. Good for MRSA and other resistant Gram +. Broad spectrum. Renal elimination.

Carbapenems

Little activity against MRSA. Stable against B-lactamases. Broad spectrum, both aerobic and anaerobic.

Imipenem

A carbapenem. The prototype. Broad spectrum, both aerobic and anaerobic. Can cause hypersensitivity, greater tendency to cause CNS symptoms and seizure. No oral administration. Renal elimination.

Cilistatin

Must be co-administered w/ imipenem to prevent its metabolism by renal dehydropeptidase-1. No oral administration. Renal elimination.

Atreonam

Mono-B-lactam. Useful against Pseudomonas. Narrow Gram negative spectrum. No cross allergies w/ B-lactam antibiotics. IV administration. Renal elimination.

Vancomycin

Cell-wall synthesis inhibitor. Not a B-lactam, so not degraded by B-lactamase or reliant on PBPs. Used for penicillin resistant bacteria (esp. MRSA). Narrow Gram + spectrum. IV admin. Oral for GI - Clostridium difficile. Renal elimination.

Vancomycin side effects

Auditory loss (w/ toxic concentrations), chills, fever, skin rashes, anaphylaxis. "Red man syndrome" due to release of histamine from mast cells.

Macrolides and Ketolides

Bind to the 50s ribosome subunit. Inhibits bacterial protein synthesis. Can inhibit other drug metabolisms by interacting w/ CYP3A4. Penicillin sub for allergic patients.

Macrolide and Ketolide uses

Mild to moderate pneumonia and upper respiratory tract infections; STDs; Legionairre's disease; atypical mycobacterial infections

Macrolide and Ketolide characteristics

Extended spectrum (Gram - and +). GI intolerance. Take on empty stomach. Hepatic metabolism.

Erythromycin

A macrolide. Extended spectrum (Gram - and +). GI intolerance. Take on empty stomach. Mild hepatic diarrhea. Oral admin if a prodrug. Hepatic metabolism.

Azithromycin

A different macrolide. No interaction w/ CYP3A4. Extended spectrum (Gram - and +). GI intolerance. Take on an empty stomach. Excreted in the bile 68 hr half life.

Streptogramins

Inhibit bacterial protein synthesis by binding to the 50s bacterial ribosome. Gram + and Gram - spectrum. Hepatic metabolism by cytochrome P450.

Quinupristin/Dalfopristin

Streptogramins. Used together are synergistic - bacteriocidal. Gram + and Gram - spectrum. Can cause joint and muscle pain and discomfort at injection site. IV admin. Hepatic by Cytochrome P450.

Lincosamide

Reversibly binds to bacterial 50s ribosome. Penetrates well into macrophages, abscesses, and bone, but not CNS. Narrow Gram + spectrum. Also good for anaerobes and bacteriodes. Oral and IV administration. Biliary.

Clindamycin

Lincosamide. Alternative to B-lactams. For parasites like babesiosis, malaria, and toxsoplasmosis. Good for some MRSA, topical for acne. Can cause Clostridium difficile infection and rashes. Better through oral admin.

Chloramphenicol

Binds the 50s subunit of bacterial ribosomes. Esp. active against H. influenza and S. Typhii. Also good for most anaerobes. Highly lipophilic, rapidly distributes to all tissue. Broad spectrum. Bacteriostatic. Oral admin. Hepatic elimination.

Linezoid

Binds to the 50s ribosome. Prevents association w/ 30s subunit. Good for MRSA. Narrow Gram + spectrum. New drug - only given to resistant organisms. GI effects, rash, myelosuppresion w/ long use. Oral and IV. Excreted in the urine.

Tetracyclines and Glycylcyclines

Bind reversibly to the 30s subunit. Many are resistant to these. Broad spectrum. Aerobic and anaerobic. Can have GI effects, promote Candida infections. Oral admin, decreased by food intake. High distribution to tissues, skin, and urine.

Tetracycline

Prototype. Chelating activity will deposit with calcium into teeth and bones. Weakens enamel and stains teeth. Not recommended in pregnancy or children under 8.

Doxycycline

A tetracycline. Most commonly used. Excellent oral absorption.

Tigecycline

A tetracycline. Effective against MRSA and other resistant strains.

Aminoglycosides

Bind to 30s ribosome (50s to lesser extent). Inhibits bacterial protein synthesis - bacteriocidal. Extended, but Gram - most important. Renal toxicity and ototoxicity (8th CN). Causes vestibular disruptions. IV. Can cross placenta. Urine excretion.

Gentamicin

An aminogycoside. Most widely used. Good against Pseudomonas aeruginosa.

Amikacin

Remains active against bacteria resistant to most other aminoglycosides.

Rifamycins

Inihibt a bacterial DNA-dependent RNA polymerase. Good for mycobacteria tuberculosis. Broad spectrum, but easy resistance. Induce P450 enzymes. Oral administration.

Rifampin

Prototype rifamycin. Good for non-mycobacterial infections as well. Broad spectrum but easy resistance. Induce P450 enzymes. Significant drug interactions. Oral administration. Liver metabolism.

Quinolone and Fluroquinolone

Inhibit bacterial nuclei acid metabolism (DNA gyrase). Broad, but not to be used for Gram +. Chelates metal ions. Do not use w/ antacids. Not recommended for pregnant women. Can cause GI symptoms. Oral administration. Renal excretion.

Ciprofloxin

Quinolone. For Gram -. Used for bacterial pneumonia in cystic fibrosis. Narrow Gram - spectrum. Excreted in the urine.

Levofloxacin

Quinolone. Increases antibacterial activity for Gram +, respiratory infections.

Sulfonamides and Trimethoprim

Folate antagonists, synergistically used together, for UTIs. Broad spectrum. Can cause crystalluria, hypersensitivity reactions. Oral administration. Renal

Sulfamethoxazole plus trimethoprim

Sulfonamide. Provides reliability outside the urogenital tract. Broad spectrum.

Colistin

Inhibit bacterial cell membrane function. Gram negative. Topically used b/c of nephrotoxicity and 8th CN toxicity

Daptomycin

Inhibit bacterial cell membrane function. MRSA usually responds. Gram +. IV administration. Renal elimination.

Metronidazole and Tinidazole

Metabolized by susceptible organisms to a toxic intermediate. Good for Clostridium difficile, protozoans, and bacteriodes.

Fidaxomicin

Macrolytic antibiotic. Inhibits bacterial RNA polymerase. Bacteriocidal. Narrow spectrum. Only for Clostridium difficile related diarrhea.

Methamine

Urinary antiseptic. Liberates formadlehyde in acid. Combined w/ urinary acidifier.

Nitrofurantoin

Urinary antiseptic. GI distress often.

Fosfomycin

Urinary antiseptic. Single dose often effective.

Selective Toxicity

killing an infected cell by targeting a pathway or structure that is essential to the infectious cell but no the host cell

Drugs that inhibit Bacterial Cell Wall Synthesis

Beta-Lactams, vancomycin, Bacitracin, Cycloserine, Fosfomycin, echinocandins (fungal)

Spectrum

describes the bacteria that are sensitive to a drug

Broad Spectrum

effective against both Gram (+) AND Gram (-) bacteria

Narrow Spectrum

effective against primarily Gram (+) OR Gram (-)

Extended Spectrum

intermediate range of antibacterial effects

Examples of Narrow Spectrum Drugs

Penicillin (G and V), Vancomycin, Clindamycin, Aztreonam

Examples of Extended Spectrum Drugs

Amoxicillin, Aminoglycosides, Cephalosporins (G1,2), and Macrolides

Examples of Broad Spectrum Drugs

Tetracyclines, Chloramphenicol, Cephalosporins (G3), Carbapenems, Sulfonamides

Bacteriocidal

Kill the invading pathogen. Ex: target the cell membrane or cell wall.

Bacteriostatic

Simply stop the invading pathogen from growing. Ex:inhibitors of protein or nucleic acid synthesis

MIC50/90

Minimum Inhibitory Concentration- the lowest concentration that inhibit growth of the organism for an antibiotic (ug/mL)

Time-dependent killing

in some bacteriocidal drugs, concentrations greater than the MIC have little benefit and may increase toxicity (penicillins and cephalosporins)

Concentration-dependent killing

important to achieve concentration 8-10 times greater than the MIC for optimal antibacterial effects. For bacteriocidal drugs like aminoglycosides and fluoroquinolones

Post-antibiotic Effect

antibacterial action continues even after drug concentrations have fallen below MIC for concentration dependent killing drugs

Gram of MRSA

Gram +

Gram of Vancomycin-resistant enterococci

Gram +

Gram of Pseudomonas aeruginosa

Gram -

Gram of Bacteroides fragilis

Gram -, anaerobic

Super-infections

Diseases caused by killing sensitive flora and allowing nonsensitive flora to proliferate and cause disease. Most common with broad spectrum antibiotics because it induces a large change in natural flora.

Beta Lactamase Activity

Major means of resistance to B-Lactam drugs by attacking the B-Lactam ring

Probenecid

slows Tubular secretion in kidneys

Major Determinant of Penicillin allergy

forms when the beta-lactam ring is opened and combines with a human protein

Properties of B-Lactam Antibiotics

high degree of selective toxicity, high incidence of hypersensitivity reactions and cross sensitivity, primarily rapid, renal excretion, CNS excitation and seizures possible

Resistance mechanisms for B-Lactam antibiotics

B-lactamases, altered PBPs, bacterial efflux pumps

Gram (+) Infections

Typically skin and wounds (strep or Staph), oral infections, strepococcal pharyngitis and scarlet fever, pneumonia and miningococcal infections

Drug to use for mild to moderate infection from organism not produxing B-lactamase

Oral Penicilin V or first generation cephalosporin

Drug to use for severe infection from organism not produxing B-lactamase

Penicilin G or parenterak cephalosporins

Prefered drug for MRSA treatment

Ceftaroline

Gram (-) infections

UTI, septicemia, abdominal infections, meningitis, otitis media, pneumonia forms and upper respiratory infections, gonorrhea

Drugs to use for Gram (-) infections

Amoxicillin or ampicillin are preferred

About this deck

By: Cassidy Bennett
Textbook:

Essential Cell Biology, Second Edition
Created: 2012-01-25
Size: 87 flashcards
Views: 6

About StudyBlue

“I have used this website for three exams, and I see a huge difference in my test results.”
Naj