Table of Contents
- 1 Which organisms are sensitive to antibiotics?
- 2 Will all the antibiotics have the same effect on the bacteria?
- 3 For which microorganisms does the Antibiogram determine antibiotic sensitivity?
- 4 How does a population of antibiotic resistant bacteria might develop from non resistant bacteria?
- 5 How does the concentration of antibiotics affect bacteria?
Which organisms are sensitive to antibiotics?
Important examples are:
- methicillin-resistant Staphylococcus aureus (MRSA)
- vancomycin-resistant Enterococcus (VRE)
- multi-drug-resistant Mycobacterium tuberculosis (MDR-TB)
- carbapenem-resistant Enterobacteriaceae (CRE) gut bacteria.
Why would some microbes be sensitive to antibiotics but not others?
Bacteria develop resistance mechanisms by using instructions provided by their DNA. Often, resistance genes are found within plasmids, small pieces of DNA that carry genetic instructions from one germ to another. This means that some bacteria can share their DNA and make other germs become resistant.
Will all the antibiotics have the same effect on the bacteria?
Antibiotics are used to treat or prevent some types of bacterial infection. They work by killing bacteria or preventing them from spreading. But they do not work for everything. Many mild bacterial infections get better on their own without using antibiotics.
How do antibiotics affect microorganisms?
Antibiotics disrupt essential processes or structures in the bacterial cell. This either kills the bacterium or slows down bacterial growth. Depending on these effects an antibiotic is said to be bactericidal or bacteriostatic.
For which microorganisms does the Antibiogram determine antibiotic sensitivity?
Antibiograms of isolates of S. pneumoniae from the rat have generally established the susceptibility of the organism to antibiotics effective against streptococci (Osimani et al., 1972).
When are bacteria most susceptible to antibiotics?
The log phase is also the stage where bacteria are the most susceptible to the action of disinfectants and common antibiotics that affect protein, DNA, and cell-wall synthesis.
How does a population of antibiotic resistant bacteria might develop from non resistant bacteria?
Bacteria can evolve quickly because they reproduce at a fast rate. Mutations in the DNA of bacteria can produce new characteristics. A random mutation might cause some bacteria to become resistant to certain antibiotics , such as penicillin.
Which antibiotics has inhibitory effect on microbes?
Effects of Antibiotics on Fermentative Bacteria For example, macrolides and tetracyclines are inhibitors of protein synthesis in bacteria (Qiao et al., 2018), inhibiting bacteria’s normal growth.
How does the concentration of antibiotics affect bacteria?
Bacterial responses to antibiotics are concentration-dependent. At high concentrations, antibiotics exhibit antimicrobial activities on susceptible cells, while subinhibitory concentrations induce diverse biological responses in bacteria.
How is antibiotic sensitivity determined?
Antibiotic susceptibility is determined by measuring the diameter of the zones of bacterial inhibition around the antibiotic disks and comparing the diameter with disk diffusion interpretive criteria updated annually by CLSI 12,15.