Learning Module 1: Miscellaneous Antimicrobials

act on gram +

act on gram -

static

cidal

static

cidal

Novobiocin

most effective on aerobic gram + cocci

inhibits ATP binding to DNA gyrase

microbe can't supercoil DNA

PK

administration

intramammary

topical

high bioavailability

poor tissue penetration

bile clearance with EH recycling

resistance

drug target modification

narrow spectrum

indications

food producing animals

mastitis

combo with pen g

aminocyclitols/spectinomycin

targets 30S ribosome site

blocks growing peptide chain

active against

gram - aerobes

Mycoplasma

rapid resistance developing

PK

administration

im

bioavailability

low po

almost 100% im

Vd low with short t1/2

cleared by urine mostly unchanged

indications

companion animals

given po

treat infectious gastroenteritis

thanks to low oral availability

food producing animals

poultry

air sacculitis (Mycoplasma)

respiratory infections

GI infections

chemoprophylaxis for synovitis

cattle

pneumonia

other respiratory infections

sc or im administration

swine

bacterial enteritis

po administration

Glycopeptides/Vancomycin

inhibit peptidoglycan synthesis

concentration dependent bactericidal

PK

low bioavailability po

short half life (2-3hr)

sometimes impregnanted on beads to treat mm infection

last resort drug

Bacitracin

inhibits bactoprenol

membrane protein that shuttles peptidoglycan monomers

stops cell wall formation

PK

low bioavailability po

nephrotoxic if given parenteral or IV

indications

companions

topical

minor eye and skin infections

dogs, cats, horses

food producing animals

swine and poultry

po administration for gram + enteritis

polymixins

positively charged peptide

bind to neg-charged lipid A of LPS in gram.- membranes

concentration-depnent bactericial

bind to free LPS in blood

prevent endotoxemia

active against

gram -

Pseudomonas

po

administered topical or oral

po

administration IV

PK

administered

PO

topical

low bioavailability po

poor tissue penetration

cationic weak bases

cleared in urine

toxic to proximal tubule

indications

companions

cats n dogs

topical teatment

ear

skin

horse

eye

uterine infections

specifically targets

Kleibsiella

Pseudomonas

eye

no approved use in food animals

derived from Bacillus filtrate

Staphylococcus

disorganize the bacterial cel membrane

protein synthesis inhibitor

Oxazolidinones/Linezolid

binds 50S

inhibit protein synthesis

resistance

no cross resistance

increased efflux

point mutation at rRNA drug target site

not yet widely used

Learning Module 1: Miscellaneous Antimicrobials
simplified

act on gram +

static

Novobiocin

most effective on aerobic gram + cocci

Staphylococcus

inhibits ATP binding to DNA gyrase

microbe can't supercoil DNA

Oxazolidinones/Linezolid

binds 50S

inhibit protein synthesis

cidal

Glycopeptides/Vancomycin

inhibit peptidoglycan synthesis

last resort drug

Bacitracin

inhibits bactoprenol

membrane protein that shuttles peptidoglycan monomers

stops cell wall formation

act on gram -

static

aminocyclitols/spectinomycin

targets 30S ribosome site

blocks growing peptide chain

protein synthesis inhibitor

cidal

polymixins

positively charged peptide

bind to neg-charged lipid A of LPS in gram.- membranes

concentration-depnent bactericial

disorganize the bacterial cel membrane

bind to free LPS in blood

prevent endotoxemia