BMS 450 Lecture Notes - Urinary Tract Infection, Gram-Positive Bacteria, Competitive Inhibition

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lemondog142

11 Jul 2014

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Pbp (penicillin binding proteins including transpeptidase) cross link peptidoglycans. If cell has drugs will be bacteriocidal. If cell doesn"t have drugs will be bacteriostatic. 4 numbered cyclic ring with amine group adjacent to ketone group. Penicillin binding proteins (pbps) cross-link peptidoglycans to form bacterial cell wall. They compete with peptidoglycans for binding to pbps and inhibit cell wall synthesis. They are bacteriostatic or bacteriocidal, depending on type of bacteria. Gut e. coli can spread these resistance factors. Lactams pass through porin channels to reach the plasma membrane and. Mutation or loss of porins can cause resistance. Mutations in pbps causing loss of -lactam binding. Multiple resistance factors (two or more of above) Act on streptococci and a few gram negatives. 95% of staphylococci (gram positive) strains have -lactamase and are resistant. These are acid stable and may be taken orally. Ampicillin* - csf, synovial, peritoneal, pleural, ear, urinary tract infections. Use with -lactams that are sensitive to lactamase.

Related Questions

1.You are working in a laboratory producing new antibiotics for human and veterinary use. One compound with potential value inhibits the action of prokaryotic ribosomes. The compound, however, was shown to inhibit the growth of animal cells in culture. What is one possible explanation for its effect on animal cells?

2. A research laboratory in pharmaceutical company is studying environmental factors that would inhibit the growth of Archaea. One question they have is if adding of antibiotic penicillin would be effective in controlling their growth. Explain to your best knowledge the probable results of an experiment in which penicillin is added to a culture of Archaea?

3. Most medically used antibiotics interfere with either peptidoglycan synthesis or ribosome function. Why do you think the cytoplasmic (cell) membrane would be a POOR target for antibacterial medications?

Compare and describe the following Prokaryotic and Eukaryotic cell structure/functions:

a. General Characteristics:

b. Size:

c. Cell Division:

d. Structures:

e. Cell Membrane:

f. Nucleus:

g. Functions:

h. Transport:

At one time, membrane biologists thought that transport proteins might act by binding a solute molecule or ion on one side of the membrane and then diffusing across the membrane to release the solute molecule on the other side. We now know that this transverse carrier model is almost certainly wrong. Suggest two reasons that argue against such a model. One of your reasons should be based on our current understanding of membrane structure and the other on thermodynamic considerations.

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exergonic

hydrophobic

hydrophobic and hydrophilic

probable

endergonic

hydrophilic

improbable

Integral membrane proteins are embedded stably in the membrane and protrude from one or both sides based on their regions.

For a protein to traverse a membrane, movement of its region(s) through the interior of the membrane would be required, which would be highly and hence thermodynamically .

tealcrocodile454

Delia, a five-year-old, woke up one morning complaining that she had a sore throat, headache and stomachache. Her tonsils appeared swollen, and a tonsular exudate, appearing as a cream-colored pus, was evident upon examining the childâs oropharynx. Her mother also took Deliaâs temperature and noted the girl was running a low-grade fever. Suspecting strep throat (streptococcal pharyngitis), her mother made an appointment with the pediatrician.

The doctor first performed a rapid strep test, which works by detecting certain cell surface proteins on group A streptococci (GAS). This test is inexpensive and can detect GAS in a matter of minutes. However, rapid strep tests that come back negative are not especially reliable; about five out of every 100 patients with streptococcal pharyngitis will have a negative rapid strep test result. Therefore, despite Deliaâs rapid strep test being negative, the doctor went ahead and ordered a bacterial culture. This was a wise decision because Delia had signs and symptoms that pointed to a case of streptococcal pharyngitis caused by the Gram-positive, nonmotile, encapsulated prokaryote Streptococcus pyogenes.

When cultures to detect S. pyogenes are performed, the patientâs sample (in this case a swab of the throat) is streaked out onto a specialized nutrient-rich agar called blood agar. Actively growing S. pyogenes can break down red blood cells (a process called beta hemolysis), and, therefore, is readily detectable on blood agar plates because a clear zone develops around its colonies. Based on the microbiology data that came back, Delia was treated for streptococcal pharyngitis. After 48 hours on an antibiotic, Delia felt much better and returned to school.

QUESTION: Assuming that Delia is not allergic to penicillin-based drugs, would a penicillin-family drug (amoxicillin, for example) typically be effective against S. pyogenes?

A. Penicillin-based drugs would effectively target the thick peptidoglycan layer within the pathogenâs cell wall.

B. Penicillin-based drugs would be ineffective since the cell wall of S. pyogenes does not contain peptidoglycan.

The porins within the pathogenâs outer membrane would exclude penicillin-based drugs, rendering these antimicrobials C. ineffective.

D. Penicillin-based drugs would effectively target the mycolic acids present in the pathogenâs cell wall.

BMS 450 Lecture Notes - Urinary Tract Infection, Gram-Positive Bacteria, Competitive Inhibition

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