Bacteria can exchange genetic material through three defferent mechanisms. What are they?
Bacteria have the ability to exchange genes and undergo
This exhange of genetic material contribute to the ability of some bacteria to acquire
an asexual genetic process, viruses called bacteriophages or simplyphages transfer genes between mating bacteria.
The process of transduction uses a bacteriophage to insert the resistant DNA into the
When a bacterium dies, fragments of its DNA are taken up by
DNA is acquired directly from the environment. (This DNA was released from another cell, through lysis or some other disruption.
These naked DNA fragments are taken up by the recipient cell through the action of ______ ________ found on the _______ _________. The fragments are then ________ into the ________ cell's DNA by ________ ________.
cell-to-cell contact for DNA to be transferred from a donor cell to a recipient cell.
It is at the _______ that DNA is transferred from one cell to another, usually in much larger quantities than the other two mechanisms.
F-pilus (sex pilus)
extrachromosomal pieces of DNA in the cytoplasm of some bacteria.
Conjugation utilizes a
Bacteria often develop their drug resistance through plasmids, also called
resistance transfer factors
Conjugation transfers a greater amount of DNA than
transformation or transduction
Genetic recombination by the three processes described above transfers
DNA leading to new strains of bacterium including antibiotic resistant strains
Antimicrobial agents include
substances used to specifically treat infectious microbial diseases.
antimicrobial agents containing substances derived from other organisms.
Spectrum of Activity. Antimicrobials can be either
Broad spectrum or Narrow spectrum drugs.
Broad Spectrum affect
a wide range of microorganisms including gram positive and gram negative bacteria.
Narrow Spectrum affect
a limited number of microorganisms or a single taxonomic group.
Inhibits organism growth.
Kills the organism.
There are numerous antimicrobials and antibiotics: some affect the _____ _____; other disrupt the ____ _______. Other groups alter _______ ________ and genetic activity. The spectrum of activity of antibiotics varies among the ______ of antibiotics.
cell wall (penicillin); cell membrane; protein synthesis; types
Resistance to antibiotics increases each
Resistance of microorganisms to antibiotics occurs through:
Overuse of antibiotics.
Genetic transfer mechanisms.
Development of neutralizing enzymes.
Alteration of pathways used by antibiotic.
Altering cell membrane permeability.
What is used for the antimicrobial susceptibility testing?
Agar Disc Diffusion
Agar Disc Diffusion
Uses paper discs impregnated with a specific concentration of the antimicrobial to be tested.
Zones of inhibition around the disc are measured and compared to those for control organisms with know zone sizes. Results are reported as