Antimicrobials Flashcards
What colors do Gram Positive bacteria Stain?
dark blue-purple
What colors do Gram negative bacteria stain?
pink to red
Bactericidal
kills bacteria
bacteriostatic
prevents replication
MIC
minimum inhibitory concentration test
-the degree of susceptibility of an organism to a specific concentration of a particular drug
Cell Wall Agents
B-lactam antibiotics
-includes Penicillins and Cephalosporins
Penicillin Classes
- Natural penicillins
- Aminopenicillins
- Potentiated penicillins
(the most common)
Natural Penicillins
-Includes Penicillin G
- narrow spectrum against non-B-lactamase producing gram positive, but also a few gram negative and many anaerobes
- bactericidal
Aminopenicillins (or “Broad-spectrum” penicillins or ampicillin penicillins)
Includes: ampicillin and amoxicillin
Potentiated Penicillins
B-lactamase inhibitor
-Clavulanate (clavulanic acid) + amoxicillin (Clavamox)
Penicillin adverse effects and contradictions
- hypersensitivity
- rodents
- GI distress-give with food if this occurs
Cephalosporins
- Bactericidal
- High therapeutic index but cross sensitivity with penicillin
USES: cystitis, skin and soft tissue infections, mastitis, respiratory infection
Side Effects: GI distress, pain on injection, diarrhea, or superinfections
First Generation Cephalosporin
- Cefadroxil
- Cephalexin
- Cephapirin (Cefa-Lak)
- intramammary infusion to treat mastitis
- OTC
Second generation cephalosporins
- Cefoxitin (Mefoxin)
- Cefaclor (Ceclor)
Third generation cephalosporins
Gram positive and most active of cephalosporins
- Cetiofur (Naxcel)
- Cattle, swine, sheep, goats, horses, day old chicks
- approved for use in dairy cattle-no milk needs to be discarded
- Cefovecin sodium(Convenia) (SQ long act)
- Cefodoxime (Simplicef)(once a day)
Cell Membrane agents
- Polymyxin B (bactericidal)
- nephrotoxic–> topical only
Protein Synthesis Agents
-interfere with translation and bacterial ribosomal subunits
- aminoglycosides(bactericidal)
- tertracyclines, chloramphenicol, macrolide and lincosides (bacteriostatic)
Aminoglycosides
Bactericidal
Side Effects: ototoxic and nephrotoxic
Dosage Forms:
- Gentomycin (Gentocin)
- Amikacin
- Neomycin
Tetracyclines
Bacteriostatic
Side Effects: binds growing bones and teeth, esophageal stricture
DO NOT ADMINISTER WITH CATIONS, NEVER GIVE RAPID IV INJECTION
-expired drugs are nephrotoxic
Dosage Forms:
- Tetracycline (Panmycin)
- Oxytetracycline (Terramycin)
- Doxycycline (lyme disease)
What is the first choice of drug for Lyme disease?(Rickettsial Disease)
Doxycycline
Florfenicol
Bacteriostatic
USED IN CATTLE AND SWINE
Dosage Form:
-Nuflor
Antimetabolites
- Sulfonamides(bacteriostatic) = interferes with folic acid
- Potentiated sulfas (bactericidal) = Side effects: crystalluria, dry eye (KCS), blood dyscrasias, hypothyroidism
EXAMPLES:
- Sulfonamides
- Sulfadimethoxine(Albon)
- Potentiated sulfas
- Sulfadiazine/trimethoprim (Tribrissen) (primor)
Nucleic Acid Agents
-Fluoroquinolones
USES: broad-spectrum and bactericidal
Side Effects: Arthropathy in young animals
Dosage Forms:
- Enrofloxacin(Baytril)
- orbiofloxacin (orbax)
- Marbofloxacin (Zeniquen)
- Ciprofloxacin (Cipro)
Lincosamides
USES: URI, osteomyelitis in dogs and cats, mastitis in cattle
Dosage Forms:
- Clindamycin (Antirobe)
- Lincomycin (Lincocin)
Macrolides
Inhibit protein synthesis
Dosage Forms:
- Azithromycin(Zithromax)
- Erythromycin
- Tylosin (tylan powder)
Metronidazole
Used to treat Giardia in dogs and cats
Used for anaerobic infections
Side Effects: neurological disorders, hepatotoxicity, anorexia
Antifungals
Infections are either superficial (skin and mucous membranes, topical) or systemic
USES: topical, oral or parenteral treatment of mycoses
Dosage Forms:
- Itraconazole(Sporanox)
- Ketoconazole
- Griseofulvin
- Nystatin, Miconazole(topical)
