Indwelling Catheter Associated UTI

Biochem enzymes MNEMONIC

“ABC” enzymes

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“TLC For Nancy” (TLCFN) Coenzymes & Cofactors

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Thiamine PyroPhosphate -TPP- requiring enzymes (B1)

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Pirydoxine (B6) coenzyme

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Cyanocobalamine (B12) coenzyme

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Succynil CoA source: “VOMIT”

Schematic of gram positive diplococci (Streptococcus pneumoniae): Note that the diplococci are lancet shaped

My assistant

Antimicrobial Agents - Inhibition of DNA and Protein Synthesis

Bacterial chromosome replication

DNA replication

Bacterial Topoisomerases 

maintain DNA in appropriate state of supercoiling 

cut and reseal DNA

DNA gyrase (topoisomerase II) introduces negative supercoils 

Topoisomerase IV decatenates circular chromosomes 

these are the targets of the quinolone antibacterial agents 

Quinolones

bind to bacterial DNA gyrase and topoisomerase IV after DNA strand breakage 

prevent resealing of DNA 

disrupt DNA replication and repair 

bactericidal (kill bacteria)

Fluoroquinolone is particularly useful against

Gram +ves: Staphylococcus aureus, streptococci 

Gram -ves: Enterobacteriacea; Pseudomonas aeruginosa 

Anaerobes: e.g. Bacteroides fragilis 

many applications e.g. UTIs, prostatitis, gastroenteritis, STIs 

Adverse effects

Relatively well tolerated

GI upset in ~ 5% of patients 

allergic reactions (rash, photosensitivity) in 1 - 2% of patients 

Inhibition of Bacterial Protein Synthesis 

Macrolides 

in 1952: Erythromycin was isolated as the first macrolide (Streptomyces erythreus) 

Newer macrolides: clarithromycin, azithromycin 

Structurally they consist of a lactone ring (14- to 16-membered) + two attached deoxy sugars 

Mode of action 

bind reversibly to bacterial 50S ribosomal subunit 

causes growing peptide chain to dissociate from ribosome → inhibiting protein synthesis 

bacteriostatic (stops reproduction)

Macrolides’ spectrum of activity

good antistaphylococcal and antistreptococcal activity 

treatment of respiratory & soft tissue infections and sensitive intracellular pathogens • e.g. Chlamydia, Legionella 

Adverse effects

Generally well tolerated

nausea 

vomiting 

diarrhoea 

rash 

Aminoglycosides

large family of antibiotics produced by various species of Streptomyces (“mycin”) and Micromonospora (“micin”) 

include: streptomycin, neomycin, kanamycin, gentamicins, tobramycin 

Structure = linked ring system composed of aminosugars and an aminosubstituted cyclic polyalcohol 

Mode of action of aminoglycosides

Bind irreversibly to 30S ribosomal subunit 

disrupt elongation of nascent peptide chain 

translational inaccuracy → defective proteins 

bactericidal 

Spectrum of activity 

broad spectrum; mainly aerobic G-ve bacilli (e.g. P. aeruginosa) 

used to treat serious nosocomial infections (hospital acquired infections)

First TB antibiotic

Used for cystic fibrosis 

Adverse effects

all aminoglycosides have low Therapeutic Index (only a small amount needed to become toxic)

renal damage, ototoxicity, loss of balance, nausea 

Horizontal gene transfer

Sooo I’m studying microbiology 2:28 am because I’m a desperate bitch Microbiology + immunology = total final grade I got a 10 in my immunology test so I’m PRAYING for a 10 in microbiology so I can get a bIG BeauTiFul 10 on my final

hey! could you do a study tips post on studying w friends who aren't doing the same subjects? like, how to make good flashcards/questions and answers etc so they can quiz you and give you hints etc even if they don't know the content?

How to Effectively Study with Friends

Using Flash Cards

Oh easy peasy! Simply write examination style questions on your flashcards - that way when your friends read the questions out to you, you’ll be testing yourself in a way that might show up on the easier exam questions. Reason being that in order to cover all the topics, your questions will tend to be somewhat simple e.g. describe the different components of x, explaining how they related to y. Obviously, flash cards aren’t the best way to study more complex interrelationships between ideas/concepts, which should be explored more in a mind map fashion. For tips on mind maps, you can check out my briefing here. 

Using Your Existing Study Notes

Other than flash cards, if you intend to study in groups for most subjects, one of the best ways to do that is to use the Cornell Notetaking System (which you can read about with my personal tips here). Writing the questions out as you study saves you the trouble of writing out questions for your friends to test you on, and as well as that, means you can test yourself almost as well without them for any times when you’re studying solitary. 

Using Essay or Long Response Questions

For long response essays, it’s better to use principles like the rubber duck method, i.e. explaining how concepts relate to each other as if the other person doesn’t know anything about it. So give your friends a list of essay questions and explain part by part in a logical sequential order how you would answer that question e.g. I would talk about the involvement of person A in event B, and explain their impact through examples C, D and E, etc. 

Choosing the Right Study Group 

Most of all, make sure you rally and encourage each other. Work with people who are like-minded, rotate between each other and have someone who will keep the others on task when you start getting too carried away when studying. Having a goal on what you intend to get finished during a group study session will make sure you always get more out of the session than studying alone!

Hope that helps! ^_^

Normal Flora

Blood, Spinal Fluid, Urine: sterile

Cutaneous surfaces (urethra, outer ear included): Staph epidermidis, Staph aureus, Corynobacteria (dyphteroids),Streptocci, Candida spp

Nose: Staph aureus, Staph epidermidis, dyphteroids, assorted streptococci

Gingival crevices: anaerobes = Bacterioides/Prevotella, Fusobacterium, Streotococci, Actinomyces

Oropharynx: Viridans group (alpha hemolytic strep), Neisseria (non pathogenic), H. influenzae (non typeable, meaning, w/o capsule), Candida albicans

Stomach: none

Breast-fed babies colon: microaerophilic/anaerobic = Bifidobacterium, Lactobacillus, streptococci.

Adult Colon: microaerophilic/anaerobic = Bacteroides/Prevotella, E.coli, Bifidobacterium, Eubacterium, Fusobacterium, Gram- anaerobic rods, Lactobacillus, E.faecalis, streptococci

Vagina: Lactobacillus, streptococci, diphteroids, yeasts, Veillonella, Gram- rods

That cell specialization…it’s pretty important.

(From our video)