Antimicrobial Treatment Pt.2 Flashcards
Describe some drugs that target cytoplasmic or cell membranes
Polymyxins (colistins): interact with membrane phospholipids; distort the cell surface and cause leakage of protein and nitrogen bases, particularly in gram- negative bacteria
Ex: Polymyxin B, Daptomycin
Describe Agents
Fungal cells are eukaryotic, present special problems in drug treatment:
Drugs designed to act on bacteria are ineffective against fungi, Similarities between fungal and human cells mean that drugs toxic to fungi will harm human tissues.
Only a few agents with special antifungal properties have been developed
Describe different antifungal agents
Polyenes: Bind to ergosterol
Azoles and allyamines: Inhibit ergosterol synthesis
Polyoxins: Inhibit cell wall synthesis
Griseofulvin: Disrupts microtubule formation
Nucleotide analog: Inhibits nucleic acid synthesis
Describe Some antimalarial drugs
Quinine: A Principal treatment of malaria for hundreds of years but Has been replaced by less toxic synthesized quinolones, chloroquine and primaquine; Several species of Plasmodium and many stages in its life cycle mean that no single drug is universally effective
Artemisinin: Has become the staple for malaria treatment
Describe some antiprotozoal drugs
Metronidazole: Widely used amebicide that Treats intestinal infections and hepatic disease caused by Entamoeba histolytica. Also treats Giardia lamblia and Trichomonas vaginalis
Other drugs with antiprotozoal activities: Quinacrine, Sulfonamides, Tetracyclines
Describe how agents treat viral infections 
Infectious agent relies on a host cell for the vast majority of its metabolic functions by Disrupting viral metabolism requires disruption of cellular metabolism of host. Measles, mumps, and hepatitis are prevented through the use of vaccines while AIDS, influenza, and the common cold attest to the need for more effective medications for the treatment of viral pathogens
Describe some antiviral agents
Nucleotide analogs: inhibit nucleic acids synthesis
Syntheticamines(amantadine): Blocks virus uncoating
Pyrophosphate analog (phosphonoformic acid): Polymerase inhibitor
Rifamycin: Polymerase inhibitor
Protease inhibitors: Inhibits processing of viral proteins
Interferons: Alter host cells
What is antimicrobial or drug resistance?
An adaptive response in which microorganisms begin to tolerate an amount of drug that would normally be inhibitory Due to the genetic versatility and adaptability of microbial population. Can be intrinsic as well as acquired
Describe an alteration of the microbiota by antimicrobials
Biota: Normal microbial colonists of healthy body surfaces and Normally consist of harmless or beneficial bacteria though A few may be pathogens. Broad-spectrum antimicrobials destroy “good” biota, along with pathogens
Superinfection: microbes that were once small in number can begin to overgrow and cause disease
Describe the help in nature of probiotics. What are fecal transplants?
Preparations of live microorganisms fed to
animals and humans to improve intestinal biota and Can replace microbes lost during antimicrobial therapy. Augment biota already there. Useful in the management of food allergies
Fecal transplant are Used to treat recurrent Clostridium difficile infection and ulcerative colitis through Transfer of feces from a healthy patient via colonoscopy. Work is under way to develop a pill containing the species to re-colonize the colon
Describe the interactions between drug and host
Drug is administered to the host even though its target is a microbe: The effect of the drug on the host must be considered ; Selective toxicity is the ideal, but chemotherapy involves
contact with foreign chemicals that can harm the host: 5% of all people taking an antimicrobial drug will experience an adverse side effect
