Notesale: Turn your study into money

Document Preview

Extracts from the notes are below, to see the PDF you'll receive please use the links above

---

Module: BIOM - 1009

Lecturer: Dr Martin

Date: 24/10/16

Medically Important Gram Positive Bacteria: Spore Forming
o

Spore formation in bacteria can provide a number of potential benefits:
 Protection in unfavourable conditions and reactivation when conditions become favourable
 This has allowed some bacteria to survive in their endospores, and be revived, after 250
million years
 Spores can survive intense temperature, radiation, chemical damage etc
...
This
will stain them green
 The slide will be rinsed and then counter-stained using safranin
 This will cause the endospores to show green and the vegetative cells to show up
orange/red

o

The following pages will describe some of the medically important, spore forming bacteria such as

Bacillus, and Clostridium

Bacillus anthracis

o

B
...
anthracis can often be found in animals, herbivores and soil


o

It is bacillus and therefore, rod shaped
It can be between 1-1
...
Transmission occurs in the following ways:
 Inhalation of spores
 Inoculation of spores through skin
 Ingestion of spores

B
...
anthracis is the presence of bacteria that are:
 Large
 Non-motile
 Gram-positive
 In the lungs, or skin samples

o

The treatment for B
...
anthracis:
 Take the anthrax vaccine for yourself, and give it to any livestock you possess
 Control the disease in animals

Clostridium perfringens

o

C
...
perfringens can be found in soil, water and the GI tract of
some animals and humans
 Humans can contract this bacterium from ingesting the food contaminated with C
...
perfringens can cause a number of different diseases:




Food poisoning
 These bacteria are the main cause of food poisoning and is often short-lived and weak
 The infection typically lasts for 24 hours
 The symptoms include:
 Abdominal cramps
 Watery diarrhoea
Gas gangrene
 This disease is classed as a medical emergency
 Trauma introduces the endospores into the
body
 These then germinate and cause
necrosis and oedema (see right)

o

The diagnosis of C
...
perfringens for food poisoning is self-limited, but for gas gangrene:
 The removal of dead tissue is required
 It also requires the administration of anti-toxins and penicillin

o

To prevent an infection of C
...
5µm in width and 3-6
...
difficile from having it in
their intestinal tract, and then having the spores
germinate
 It is an opportunistic pathogen

o

The bacteria produce 2 toxins plus the enzyme hyaluronidase which can result in varying degrees of
disease:
 Low level, persistent, explosive diarrhoea
 This is usually non-fatal and may go away soon
 It is caused by the minor death of the intestinal cell wall
 Pseudomembranous colitis
 This is a life-threatening disease that is caused by large sections of the intestinal cell
wall being sloughed off
 This often causes perforations of the colon and can lead to infection of the body
by faecal bacteria
 This is a major cause of death in elderly patients

o

Diagnosis of C
...
difficile, as some
antimicrobial drugs cause an imbalance of intestinal flora and allow the germination of the
bacterial spores
 This can be confirmed by isolation the bacteria from faecal matter or by showing the
presence of the toxins A and B using an immunoassay

o

Treatment of C
...
difficile is done by taking the following precautions:
 Hygiene should be key in hospitals as it is a known as a nosocomial infection
 There is evidence to indicate that probiotics can be useful in preventing the bacterium from
thriving
 Aseptic techniques such as glove wearing should be standard
 Endospores often survive floor cleansing; however, bleach is effective in killing them

Clostridium tetani

o

C
...
tetani by getting wounds infected with soil, dust or animal faeces

o

C
...
tetani is comprised of the following:
 Characteristic muscle contraction (which often shows it’s too late)
 The bacteria cannot be cultured fast enough as it grows slowly in culture and is extremely
sensitive to oxygen

o

The treatment for the bacterium consists of:
 The cleansing of wounds to remove the endospores
 The administration of immunoglobulins to remove the toxin
 Muscle relaxants may be used to lessen the symptoms
 Antimicrobial drugs such as penicillin are used
 Finally, the active immunisation with the tetanus toxoid is used

o

To prevent an infection of C

---