Chapter 11: How Bacteria Became Resistant to Antibiotics

9 Pages
Unlock Document

Microbiology and Immun (Sci)
MIMM 465
Albert Berghuis

Chapter 11 How Bacteria Became Resistant to Antibiotics Costs of Antibiotic Resistance y There were many MRSA in the US where they were common nosocomial infection causes y They could be known as multiply resistant S aureus with the way that they were resistant to everything y Only vancomycin was effective against it and there is some resistance building up against it too y Studies were done and found the 21 of all S aureus infections were from MRSA and that the cost to treat each of these patients was 2500 and even 3700 if they had to be hospitalized It was expensive because y Vancomycin is more expensive y Necessary to isolate patients y MRSA patients stay longer in the hospital y The death rate was very high at 21 25 times higher than normal y They are not actually more virulent but it is just more difficult to treat them therefore the deaths are largely because of antibiotic resistance y There are also costs associated with the patient because they do not work and businesses get disruptedOverview of Resistance Mechanisms y Mechanisms can be grouped into 4 categories y Restricted access of antibiotic to target o Porins of grambacteria that restrict diffusion of antibiotics access OM and pump antibiotics out of bacterial cytoplasm o Can be divided into groupsOuter Membrane Porins y In Gram negative bacteria OM functions as barrier to antibiotic entry this is the reason why vancomycin cannot work against gram negative bacteriabecause it is too bulky y This advantage can be increased by having porins which are located on the OM that further limit diffusion where a single mutation can confer resistance to more than more type of antibiotic y Although less effective than other methods the increase in resistance can be very disastrousReduced Uptake across Cytoplasmic Membrane y Prevents entry of antibiotics into cytosol where it has to act y It is quite a rare mechanismy However sometimes the antibiotics use a transporters as is the case for aminoglycosides y The transporter is actually very important for the bacteria so the bacteria cannot mutate it so no resistance develops unless it can find an alternative y Some are more resistant to aminoglycosides in anaerobic conditions where E coli is 10 times more resistant to aminoglycosides when growing anaerobically y This is probably because of less uptake of the antibiotic o Can also have active efflux mechanismsResistance to tetracyclines y Some proteins pump antibiotics out through efflux pumps y Was an energy dependent transporter of tetracycline out of the bacterium
More Less

Related notes for MIMM 465

Log In


Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.