M5:T4: antimicrobial agents

• define chemotherapeutic agents

  • chemical agents <- inhibit growth inside body
  • range of spectrums for activity
  • types: synthetic or natural
• synthetic anti-microbial agents

  1. growth factor analogs <— in organism enviro
  2. inference with growth of bacteria
  3. does not produce a requirement for cell growth
• explore antibiotics

  • chem subs produced by certain microbes, active against others
  • produced by: action bacteria, fungi and bacillus
  • can be natural or chemical
  • vary effects on bacteria
  • produced as 2nd metabolite
• properties of antibiotics

  1. soluble for body and blood
  2. selectively toxic
  3. can modify
  4. stability - toxicity and storage
  5. low cost
• examples of antibitoics

  1. penicillin which is gram -ve
  2. toblaymyich which is gram +ve
• why can mycobacteria resist antibiotics

  • due to longevity cell acid in cell wall
  • difficult of antibiotics to permeate cell wall
• explore production of antibiotics

  • aerobic process
  • uses stirred femenatators
  • nutrients: lactose, glucose, corn steep liquor and abomination
• Factors that increase production

  1. Improvement and manip of media conditions
  2. isolation of improved antibiotic producing strains
  3. develop of submerged culture techniques
  4. improve in recovery methods
  5. selection of mutant strains
  6. add of chemical building blocks to media
• screening

  • most isolation = antibiotics
  • most new antibiotics fail toxicity and therapeutic test
  • 15 yrs with 1 billion dollars
• compare types of targets for antibiotics

  1. inhibit cell wall synth: B-la tame antibiotic, fungal and penicillin
  2. inhibity protein synthesis: target ribosomes, interferes with transcript, produced by bacteria
  3. inhibits plasma membrane: punctures a hole
  4. inhibit sythesis of essential metabolites
  5. inhibity nucleic acid synthesis
• compare penicillin and cephalosporin

  penicillin: 5 membrane ring, 1st line and production of fermentation

  cephalosporin: 6 membrane ring, more resistant to beta-lactamase and has Sulfur ring
• different types of penicillin

  2 types

  1. injected: natural, carbenicillin (-cooh), kills +ve and -ve, acid stable and Beta-lac sensitive

  2. oral: semi-synth, oxcallin, ampicilin which is beta-lact sensitive amine and all acid stable
• what is the difference between natural and synthetic penicillin

  natural must be injected and is gram +ve only <— beta-lactase sensitive

  • synth take orally due to stable acid and more resistance to beta-lactase
• compare 2 types of polypeptide antibiotics

  1. bacitracin: bacillus, topical application and against gram +ve

  2. vanocmyoin: glycoproteins, last line, bacteria = beta lactase which changes substrate site and destory antibiotics
• what are … used for

  isoniazid: growth analog, for mycobacteria, interferes with synthetic of my logic acid

  daptomycin: gram +ve and forms pores in cyto mem

  platensimycin: new antibiotic, effective against MRSA and vancoymcin resistant enteroccoi
• antiviral drugs

  • target host structure and are toxic
  • most common and successful: nucleoside analogs “AZT”, which blsocks revser transcriptase and production of viral DNA
  • protester inhibitors prevent viruses from succesfully fsuing with host cell
  • neuramindase inhibitors like tamiful prevent influenZa
• what do interferon prevent

  viral multiplication by stimulating anti-viral proteins in uninfected host cells
• antibiotic resistance

  • ability of micro-organism to resist the effect of chemotherapeutic agent
  • few pathogens develop resistance all known agents
• explore how antibioptic resistance occurs

  • needs genes encoded to resistance

  1. gene transfer - genes from AR gene in antibiotic transferred to microbe
  2. gene can = enzyme which changes the site
  3. gene can = some proteins that can bump antibiotic from inside to outside the cell = antibiotic not to work inside the cell
  4. can = a protein to prevent antibiotic penetration or diffusion into bac cell
• what is the effect of penicillinase on penicillin

  • can destroy beta lactase ring which causes it not to bind to enzyme gene anymore = ineffective
• gene conjugation 


  ability of the cell to bind and swap DNA from 1 to another
• how microbes have become resistant

  • adapted my mutation
  • graining resistance genes through horizontal gene transfer
  • overuse and misuse
• vaccines 


  subs that induces immune repsonse to protect indiv from future infection
• 2 types of vaccines

  1. whole cell: antigen stimulates immunity but there is no pathogen
  2. vaccines with microbe parts: like plasmid with gene, transfer 1 cell to another
• 2 types of whole cell vaccines

  1. killed cells: stimulate immunity pathogen and does not multi but still active
  2. live and attenuated: can multi and boost immune stimulate = antibiotics
• conjugate vaccine 


  attaching polysaccarides to a toxic and improve immune repsonse of polymscaarides making it no immunogenicity as proteins
• herd immunity 


  occurs when a large portion of a population becomes immune to a disease,