Dr. Kimmel would like to eliminate the carrier state of Streptococcus pneumoniae

Question

Dr. Kimmel would like to eliminate the carrier state of Streptococcus pneumoniae. She is particularly concerned about finding ways to prevent S. pneumoniae-caused otitis media without the use of antibiotics because she is well aware that using antibiotics to treat S. pneumoniae infections has caused problems. Amoxicillin worked for her as a child, but today there are many antibiotic-resistant strains of S. pneumoniae. Do not use more than three sentences for each part. Any information provided after this will be ignored.

a.   Describe how amoxicillin affects bacterial cells. (What is the target site? What does amoxicillin do?)

b. What is the name of the protein encoded by blaA? [BlaA is not an acceptable answer.] Explain: why is this an appropriate name?

c. How does this protein allow bacteria to survive exposure to amoxicillin in the body?

d. Does blaA confer resistance to the antibiotic tetracycline? Briefly explain.

e. There are several possible mechanisms that could lead to ‘spreading’ of amoxicillin-resistance from a S. pneumoniae cell (strain 1) that is amoxicillin-resistant to a S. pneumoniae cell that is susceptible to amoxicillin (strain 2). Describe the 3 possible mechanisms.

Explanation / Answer

A. Amoxicillin acts against gram positive and Gram Negative bacteria. It acts by inhibiting bacterial cell wall synthesis. Lack of bacterial cell wall results in death due to lysis of bacteria.

B. It is a gene which encodes the enzyme beta lactamase which break down the antibiotic ampicillin.

C. beta lactamase provides antibiotic resistance by breaking the antibiotics structure. Through hydrolysis the enzyme break the beta lactam ring open deactivating the molecules antibacterial properties.

E. Plasmid mediated resistance- transfer of antimicrobial resistance coding genes which are carried on plasmids.

Antibiotic resistance spreads through bacterial populations both "vertically" when a new generation inherit antibiotic resistance genes and "horizontally" when bacteria share or exchange some sections of genetic material with other bacteria. By undergoing a simple mating process called conjugation bacteria can transfer the genes encoding resistance to antibiotics.

viruses are another mechanism for passing resistance traitse between bacteria. Any bacteria that acquired resistance genes whether by spontaneous mutation and genetic Exchange with other bacteria have the ability to resist antibiotics.

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