Organophosphate Poisoning VS Atropine Poisoning

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Clostridium tetani

Gram+, anaerobe, spore forming, motile, rod.

Neurotoxin: Tetanus Toxin blocks glycine and GABA and produces a SPASTIC PARALYSIS.

TETANUS

Opisthotonus

Risus  Sardonicus

Severe mucle spasm

Bacterial strain X is resistant to Ampicillin and sensitive to Gentamycin. Bacterial strain Y is resistane to gentamycin and sensitive to Ampicillin. Bacterial strain X and Y are grown in mixed culture in medium without antibiotics, then the culture is plated on medium containing both ampicillin…

Microbiology Mnemonic

STD: Chlamydia Trachomatis’ serotypes

“Eye Don't Know why people don’t use condoms”

Most common BACTERIAL STD in the US

Serotypes: D-K : nongonococcal urethritis, cervicitis, PID

Eye: Inclusion conjunctivitis. 

Pneumonia (staccato cough) / Inclussion conjunctivitis in neonates / infants

STD: L imphogranuloma Venereum

L1,2,3

Africa, Asia, South America

Swollen lymph nodes, ulcers, fistulas -> Genital elephantiasis

tr AC homa

A-C serotypes (A,B,Ba,C)

Follicular conjuntivitis -> Conjuntival scarring -> inturned eyelashes -> corneal scarring -> BLINDNESS

MICROBIOLOGY MNEMONIC

My favorite band: the Killers (and I’m gonna see them for the second time in 3 weeks!!!!!!! I’m SO excited!!!!!!)

There’s this mnemonic to remember encapsulated organisms that use capsule layers as their major mechanism of pathogenicity. 

Capsules are slippery layers and can not be phagocyte. To remember that, just remember this Killer’s song called “All the pretty faces”

This is the only way I can remember this mnemonic, here it goes…

S ome   K illers  H ave   P retty   N ice   Capsules

S treptococcus pneumoniae

K lebsiella pneumoniae

H aemophilus influenzae

P seudomona aeuroginosa

N eisseria meningitidis

C riptococcus neoformans

Colon: pseudomembranous colitis due to Clostridium difficile (pseudomembranous inflammation) Note the gray-yellow pseudomembrane covering the entire mucosal surface. Damage is due to a toxin produced by C. difficile. Similar to diphtheria, the toxin produces necrosis of the mucosa and submucosa without actual invasion by the bacteria. A toxin assay of stool is the best method for diagnosing the disease. Ampicillin is the MC drug causing pseudomembranous colitis and does so by destroying colonic bacteria that normally keep C. difficile in check.

Micobacterium tuberculosis DX

Auramine-Rhodamine staining bacilli: fluorescent apple green (sensitive but not specific). If positive, do acid fast.

Acid Fast

Lowenstein-Jensen medium: aerobic, slow growing (2-3weeks)

PPD or Mantoux Test: measure 48-72h after. POSITIVE: >/= 5mm in VIH+ pts, >/=10mm in high risk population (IVDA, poverty, immigrants from high TB area, physicians, nurses), >/=15mm in low risk population

Positive indicates exposure, but not necessarily active disease.

Quantiferon-TB Gold Test: measures IF-gamma

Niacin producers

Catalase negative at 68° and catalase active at body T°

No serodiagnosis

11.19.17

2 more days until break

Music mood: Mili - Miracle Milk

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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