Elek Test To Document Toxi Production Of Corynobacterium Diphteriae

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 

Passive Immunotherapy

Active immunotherapies:

Cytokines (TNFa IL-2, IFNs)

Cancer vaccines

tumour CTL and APC

DC priming

Passive immunotherapy:

Administration of monocolnal (clone derived asexually from a single individual or cell) antibodies which target either tumour-specific or over expressed antigens

Generally comprised of antibodies made outside of the body (in a lab)

administered to patients to provide immunity against a disease, or to help fight existing disease

do not stimulate a patient’s body to ‘actively’ respond to a disease the way a vaccine does

immunogen is given several times to induce a strong secondary response

blood serum contains many different antibodies to the immunogen

most immunogens have multiple antigenic epitopes 

each stimulates a different B cell clone/receptor –> polyclonal antibody (PAb) response 

Monoclonal antibody (mAb) therapy is the most widely used form of cancer immunotherapy. Monoclonal antibodies cannot be purified from a polyclonal sample and are derived from a single clone/specific for a single epitope.

Antibodies in cancer therapy:

Trigger immune system to attack cancer cells 

Block molecules that stop the immune system working (checkpoint inhibitors)

 Block signals telling cancer cells to divide 

Carry drugs or radiation to cancer cells

Checkpoint inhibitors

Immune system uses particular molecules to stop it being over activated and damaging healthy cells  - these are known as checkpoints

some cancers make high levels of checkpoint molecules to switch of immune system T cells which would normally attack cancer cells

examples of targets include CTLA-4, PD-1 and PD-L1 (programmed death ligand 1)

Blocking cell division signals 

Cancer cells often express large amounts of growth factor receptors on their surface –> rapid cell division when growth factors stimulate them

some monoclonal antibodies stop growth factor receptors working

either by blocking the signal or the receptor itself 

cancer no longer gets signal to divide

Carrying drugs/radiation

drugs or radioisotopes can be attached to monoclonal antibodies

the mAB binds to the cancer cell, delivering directly

known as conjugated MABs

Live, attenuated Vaccines Available in the US

Live vaccines induce HUMORAL & CELL-MEDIATED immunity

MRS.  V.Z.  FYI  MAP

M umps / M easles

R ubella

S mallpox

.

V aricella Z oster

.

F rancisella tularensis

Y ellow Fever

In fluenza (intranasal)

.

M icobaterium bovis (BCG)

A denovirus

P olio (sabin)

Indwelling catheter associated UTI

Catheter induced UTI

Typical :e.coli,Klebsella pneumonia,staph.saprophticus,proteus.mirabilis(lactose fermenters)(eat protein to be the cool member of the sapron staff club)

Atypical opportunistic:Pseudomonas aeroginasa.(non lactose fermenter)

Summery of UTIs

E.coli and klebsella are leading cause of uti..

staph saprophticus  uti in sexually active women.

Enterococi(strptococcus family ) oppurtunistic uti

U.urealyticu known cause of urithritis but needs special media rich in urea and cholestrol

Me durning finals.

April Background

I created this new background for April! A reminder to all the great girls out there who are awesome human beings!

For a high quality foto, check out the link in my previous post!

ONE STEP AT A TIME: Free Printable

Hellooo! Yesterday I reached 15.000 followers (!!!!!!!!!!), which is so, so crazy. I would have never ever expected that when I first created this blog, so THANK YOU ALL SO MUCH <3 I love every single one of you.

To celebrate, I decided to make some printables yayyyy!! It’s a weekly planner that comes in the following options: blank, lined, graph and 2 columns (lined). Also I made portuguese versions yeahhh

Download links:

English: blank / lined / graph / 2 columns

Português: branco / pautado / quadriculado / 2 colunas

If you have any problem with it, please let me know. And also tag me if you use it! x

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 …

Recurrente infections with catalase positive organisms in Chronic Granulomatose Disease (CGD)

Pizza heaven! Quick and easy! Recipe up on blog: www.studydiaryofamedstudent.wordpress.com