Latest Posts by t-b-a-blr-blog - Page 6

Pneumonia

 “Pneumonia is called the old man’s friend because, left untreated, the sufferer often lapses into a state of reduced consciousness, slipping peacefully away in their sleep, giving a dignified end to a period of often considerable suffering.” -Dr John Pillinger

Pneumonia is a major cause of morbidity and mortality worldwide, the 6th largest cause of death in the USA. It is also economically costly in antibiotics, time off work, and hospitalisation

In half the cases the cause is not identified

In those where a cause is identified, S. pneumoniae is the most common cause

The reservoir is usually humans (oneself or a contact) 

spread is through respiratory droplets

Community acquired eg Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, Mycoplasma pneumoniae, Chlamydia pneumoniae

Noscomial (hospital acquired) eg Enterobacteriaceae, Staphylococcus aureus, Anaerobes, Pseudomonas aeruginosa

Many patients have an underlying condition, e.g. bronchitis, asthma, a viral infection, tumours

Characterised by the alveolar sacs filling up with pus, giving rise to a purulent sputum

Symptoms

Results in chest tightness or pain, difficulty in breathing, fever or hypothermia, reduced blood oxygen, coughing to clear mucus, chest will sound “dull” when tapped, tachypnea, tachycardia (>100 bpm) or bradycardia (< 60 bpm), central cyanosis, altered mental status.

Streptococcus pneumoniae: Rust-colored sputum

Pseudomonas, Haemophilus, and pneumococcal species: May produce green sputum

Klebsiella species pneumonia: Red currant-jelly sputum

Anaerobic infections: Often produce foul-smelling or bad-tasting sputum

Diagnosis

X-ray showing infiltrates

Elevated temperature

Changes in WBC counts

Culture confirmation

Serum chemistry panel

Arterial/venous blood gas 

Serum free cortisol value and lactate level

Treatment

Intensive treatment, potentially to ITU level

Tailored antimicrobials if possible - limited options with viruses

Treatments include: analgesia and antipyretics, physiotherapy,  bronchodilators and N-acetylcysteine, suctioning and bronchial hygiene, ventilation 

Pathogenesis 

Causative agents can enter the lungs through inhalation, aspiration, spread across mucous membrane (some viruses), haematogenous spread (occasionally, e.g. IV drug users with S. aureus septicaemia) and penetrating injury (rare).

Immune response is triggered in the lung and there are local defence factors in the respiratory secretions

Cilia, if functioning, will move material up the respiratory tract, but if damaged this physical defence is impaired

The lungs also have a resident macrophage population (alveolar macrophages) but they are of limited use against several respiratory pathogens that possess a capsule

some organisms can even replicate in these cells

Damage to the lung is caused by the microbes and the immune response

 Enzymes released by the bacteria

Factors released by immune cells that cause local irritation and cell apoptosis

Systemic manifestations follow eg

Oxygen deprivation – thickening of the membranes reduces gas transfer

Systemic shock – especially with Gram-negative bacilli such as Haemophilus influenzae

Dr Warhol’s Periodic Table of Microbes

56. Ba. Bacillus

There are more than 300 species of Bacillus, which is a whole whopping load of microbes. Just to wrap your head around that number, if you talked about each one for 1 minute you’d be talking nonstop for 5 hours! Take that TedTalks!

Starting with the basics, these organisms found all over the world, predominantly in soil but microbes go where they please, so they have been found in undersea hydrothermal vents as well as in the stratosphere. They are rod-shaped and form spores.

Just to list a few of the most noteworthy and awesome Bacillus species:

Abyssalis: found more than a mile and a half down at the bottom of the South China Sea.

Anthracis: causative agent of Anthrax, the disease, not the band; death, disease, toxins, yahoo!

Azotofixans: fixes nitrogen.

Canaveralius: StarFleet Academy space bacteria living on the walls of the Kennedy Space Center!

Cereus: you get to play with this in General Microbiology, a pathogen causing foodborne illness.

Decolorationis: for you art history majors, isolated from decaying parts of a mural in the Roman necropolis in Carmona, Spain.

Megaterium: it can consume cave paintings.

Stratosphericus: found in high concentrations orbiting the Earth with satellites around 6 miles up!

Subtilis: the grass bacillus; used for industrial enzyme secretion.

Thuringiensis: absolutely famous for producing the BT toxin used as a natural insecticide.

Bacillus cells are Gram positive rods that measures about 1 micron wide by 4 to 10 microns long, but with more than 300 species you will see a range of sizes.

Everyone needs their own Periodic Table of Microbes from https://www.etsy.com/no-en/shop/WarholScience.

Copyright 2016 Warhol.

Stuff in my Office

From 1930. This well-dressed young scientist is experimenting with The Air. Exactly what he is doing is a mystery.

July 25 …. I finally get it!  He’s holding an eye dropper with a bulb on the end. I thought it was a pair of chopsticks! He’s picking up pieces of paper using the vacuum from squeezing the bulb! Still very formal, though …

11.19.17

2 more days until break

Music mood: Mili - Miracle Milk

One possible cover design for The Book

Coming soon.

Me durning finals.

how am i always so behind in my work ??

(i do know the answer to this, it’s called procrastination lmao)

(Day 4/100 days of productivity) - Haemophilus Influenzae card!

Today was mostly spent working on research, textbooks, but and making flashcards like this for microbiology!

That’s why we have skin and immune system. 

it’s technically kinda busy work but i still love it

Which Microbe Would You Be?

Buzzfeed has a quiz on what bacteria would you be, based on your personality.

I was a Salinicola salarius. (Which isn’t on my Periodic Table of Microbes!)

https://www.buzzfeed.com/grandon/which-bacteria-are-you-based-on-your-personality-3dk99?utm_term=.am4B9qO8B#.ab5oX2B0o

Follow on Twitter @warholScience

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

• Microbiology cheat sheets for the comprehensive final. We were allowed two pages, front and back. I ended up getting a 95%! •

Antimicrobial Agents  - Cell wall inhibitors

Based on mode of action • divided into families based on chemical structure

 Modes of action Interference with: 

cell wall synthesis 

protein synthesis 

nucleic acid synthesis 

plasma membrane integrity 

metabolic pathway 

Inhibitors of Bacterial Cell Wall (peptidoglycan) Synthesis 

The Beta-lactam Family 

The Glycopeptides 

Peptidoglycan is composed of N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM) repeat units, and amino acids.  Each NAM is linked to peptide chain and the peptide chains are cross-linked.

β-lactams 

Includes penicillin derivatives (penams), cephalosporins (cephems), monobactams, and carbapenems.

class of broad-spectrum antibiotics containing a β-lactam ring

Bacterial transpeptidase enzymes are responsible for catalysing cross-linking of the peptide chains

β-lactam ring bind to these transpeptidases – this inhibits cross-linking between peptide chains and prevents synthesis of stable PG

Cell wall synthesis ceases and the bacterial cells eventually die due to osmotic instability or autolysis. 

Glycopeptides 

Polypeptide agents - basic structural elements amino acids 

Vancomycin: 

complexes with peptide portion of peptidoglycan’s precursor units 

vancomycin is a large hydrophilic molecule able to form hydrogen bonds with the terminal D-alanyl-D-alanine moieties of the NAM/NAG-peptides

preventing PG transglycosylation reaction – PG precursor subunits (NAG-NAM+peptide) cannot be inserted into peptidoglycan matrix;

Vancomycin also alters bacterial-cell-membrane permeability and RNA synthesis

Uses:  serious Gram positive infections e.g. MRSA wound infection

Adverse effects:

damage to auditory nerve 

hearing loss (ototoxicity) 

“Red man/neck” syndrome - rash on face, neck, upper torso 

….and that is how viruses go about their non-lives!!

my biology professor at the end of a lecture about viruses, presumably, i wouldn’t know, i wasn’t paying attention, i’m using context clues here (via scienceprofessorquotes)

My assistant

This disease typically affects children because, well, kids are gross and have fewer inhibitions about sticking their poop hands in their mouth

Sketchy Medical on Enterobius vermicularis (via medschoolmanic)

If you cannot grasp what I have just explained, you should just leave and study economics!

Microbiology professor, first lecture (via scienceprofessorquotes)

Remember to use your sponge to replace any bacteria on your dishes accidentally removed by the act of eating.

Microbiology professor (via scienceprofessorquotes)

nasty moodboard

[x]

 30 . 06 . 2017  Microbiology notes !!!  Yesterday I took my physics final exam and it went great: I got a 27/30, which is way more than what I expected as Physics is one of my worst subjects.  My next exam, microbiology, is in four days and I’m starting to feel a bit anxious about it as it’s a pretty tough exam but I’ll try to do my best ! 

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 

Without immunity, we’RE JUST BAGS OF NUTRIENTS!

Microbiology lecturer (via scienceprofessorquotes)

Infectious bacterial diseases and where to find them

That cell specialization…it’s pretty important.

(From our video)

[17 Dec 2017] (i thought i’d posted but it’s not appearing? ):) so sorry for the lack of original posts all these months! school has been so tough & i’ve just completed my mid-sem assessments & it’s finally my break! can’t wait to unwind and catch up on my sleep ;-;

Review sheets from my microbiology exam last Monday 🔬

Who wants a box of chocolates when you can have a petri dish of bacteria?