S3M2-micro – Flashcards
Unlock all answers in this set
Unlock answersquestion
| List 8 Gram positive genera |
answer
| 1. Staphylococcus 2. Streptococcus 3. Enterococcus 4. Listeria 5. Cornybacterium 6. Bacillus 7. Clostridium 8. actinomyces |
question
| List the important acid fast organisms (remember that acid fast are gram+ variants that have myocolic acids attached via arabinogalacitan to peptidoglycan) |
answer
| 1. Mycobacterium a. M. tuberculosis b. M. leprae c. M. avium complex 2. Nocardia 3. Corynebacterium may be partially acid fast |
question
| What are two examples of mollicutes(remember that mollicutes are gram+ variants that have lost their cell wall) |
answer
| 1. mycoplasma 2. ureaplasma |
question
| Whare are 3 important spirochetes(remember that spirochetes are gram- variants that have a flagella located between the outer membrane and PG layer) |
answer
| 1. borrelia 2. leptospira 3. treponema |
question
| Describe chlamydiaceae |
answer
| unrelated to gram - have plasma and outer membranes including LPS but no peptidoglycan layer. They have a dimorphic life cycle: elementary bodies (environmentally resistant extracellular form which have CRPs that cross link to provide the cell with rigidity) and reticulate bodies (environmentally sensitive form) the CRPs in the elementary bodies play the role of PGlayer. Major pathogenic genera: Chlamydophila Chlamydia |
question
| What are three examples of Beta lactam antibiotics and what do they generally target? |
answer
| penicillins, cephalosporins, carbapenems, monobactams bind and inhibit primarily transpeptidases via their structural analogy to the PG subunit NEW PG is weak and leads to cell lysis |
question
| Give 2 examples of glycopeptides and explain generally their MOA |
answer
| Vancomycin and teicoplanin Large molecules that prevent transpeptidation and interfere with transglycosylation by binding the D-ala-D-ala portion of hte stem peptide and getting in the way. |
question
| Exaplain the MOA of Bacitracin (polysporin) |
answer
| popypeptide that prevents dephosphorylation of the Und-P-P molecule, which prevents its recylcing. This leads to a lack of Und-P, which interferes with several processes including PG syntehsis, LPS, capsules, teichoic acid synthesis etc... |
question
| Explain the MOA of Cycloserine |
answer
| used to treat mycobacteria Prevents the formation of D-ala-D-ala through the inhibition of both alanine racemase and D-ala-D-ala synthetase, which puts these two amino acids together in preparation for their attachment to hte peptide tail of the PG monomer. |
question
| Explain the MOA of fosfomycin |
answer
| inhibits MurA, which is involved in the production of NAM and NAG |
question
| What is the MOA for Tunicamycin? |
answer
| nucleoside analogue with prevents NAM-P to Und-P transfer |
question
| Which drug specifically targets the production of mycobacterial cell envelope components i.e. mycoloic acids? |
answer
| isoniazid |
question
| Which drug specifically targets the production of mycobacterial cell envelope components i.e. arabinogalactan? |
answer
| ethambutol |
question
| What is the MOA of lysoszyme as an innate antibacterial? |
answer
| it cleaves the bonds between the NAM and NAG sugars and leads to bacterial cell lysis. |
question
| What are two examples of transglycosylase inhibitors which have large complex structures? |
answer
| ramoplanin and moenomycin |
question
| how does the endopeptide lysostaphin work? |
answer
| cleaves the pentaglycine bridge found between stem peptides in S. aureus, resulting in weakening of the PG and lysis of hte bacterial cell. They have shown some promise in treating infection. |
question
| 2 sporulating species of bacteria |
answer
| bacillus (aerobe) clostridium (anaerobe) |
question
| 2 microaerophiles |
answer
| camylobacter helicobacter |
question
| Quinolones (e.g. ciproflaxin) MOA? |
answer
| target DNA synthesis; bacterial topoisomerases (gyrase and topoisomerase IV) |
question
| Sulfonamides moa? |
answer
| inhibit folate synthesis, which is required for DNA synthesis. |
question
| Trimethoprim moa? |
answer
| prevents folate reduction |
question
| Rifampin moa? |
answer
| Targets RNA pol |
question
| Aminoglycosidse and tetracyclines target which ribosomal subunit? |
answer
| 30s |
question
| Chloramphenicol, lincosamides, macrolides, oxazolidinones and streptogramins target which ribosomal subunit? |
answer
| 23s portion of the 50s ribosomal subunit |
