Toxins and Microbiology Flashcards
What are the most common worms in the UK?
Pinworms
Tiny, sit on anus, very itchy
What is lactoperoxidase?
An antimicrobial present in breast milk
Which bacteria causes parotitis?
Staph aureus
What is achlorhydria?
Don’t produce enough gastric acid
More susceptible to certain infections
Name some microorganisms that are resistant to stomach acid
Mycobacterium tuberculosis
Hep A
Polio
Coxsackie
Does the small bowel usually contain bacteria?
No
It is normally sterile
What is the main role of the colon?
Water recovery
What do eosinophil granules contain?
Peroxidases
Cationic proteins
Major basic protein
Eosinophilia only occurs in which conditions?
Asthma
Hay fever
Parasitic infection
How do we treat roundworms?
Can operate to remove
In poorer countries cannot operate as people are malnourished
Give them a drug to kill the roundworm
Expelled from anus
Where is the guinea worm most prevalent?
Ghana
Sudan
How does the guinea worm spread?
Ingested by humans from fresh water ponds
Flies ingest ovum
Flies protect ovum to the human duodenum where the worm burrows through the retroperitoneum
Moves down to the feet and expelled at a large ulcer
Moves subcutaneously
Intensely painful
What are basophils?
Mast cells in the blood
In cholera, the losses of water can be up to …
1 L/hr
What is the mortality of cholera if untreated?
60%
Where are the majority of macrophages in the body?
Liver
What are the 3 main sites for macrophages?
Liver
Lungs
Spleen
How many portal systems are there in the human body and name them?
2
Hepatic
Hypothalamus-hypophyseal
What is a portal system?
One capillary system flowing into another capillary system
Where are sinusoids present?
Liver
Spleen
Bone marrow
Give some causes of liver failure
Viral hepatitis Alcohol Drugs Industrial solvents Mushroom poisoning
What types of infection are more likely to occur during liver failure?
Bacterial
Fungal
How does hepatic encephalopathy occur in liver failure?
Failure of urea cycle
Increased plasma ammonia
Moves through BBB
Toxic to the brain
What are the consequences at porto-systemic shunts of portal hypertension?
Oesophageal varices
Haemorrhoids
Caput medusae
What does MALT stand for?
Mucosal associated lymphoid tissue
What does GALT stand for?
Gut associated lymphoid tissue
GALT is nodular in which 3 locations?
Tonsils
Peyer’s patches
Appendix
What are the 3 types of tonsils?
Palatine (normal)
Lingual (back of tongue)
Nasopharyngeal
Where do the tonsils drain into?
Cervical lymph nodes
Why do we need ileocaecal lymphatic tissue?
In case of reflux of large bowel contents into the ileum
Describe how typhoid fever affects the gut
Inflamed Peyer’s patches in terminal ileum
Can perforate and kill patients
Where are there unsafe levels of arsenic?
Bangladesh India Nepal Pakistan (In wells)
What are obligate aerobes and give 2 examples?
Must have oxygen to live
Pseudomonas and mycobacterium
What are obligate anaerobes and give 2 examples?
Die in the presence of oxygen
Bacteroids and clostridial organisms
What are facultative anaerobes and give 2 examples?
Prefer oxygen but can live without it
Gram negative enteric bacteria (eg. Ecoli)
Gram positive skin dwellers (staphylococcus)
Where are the anaerobic zones in the GI tract?
Parts of the mouth - deep in taste buds, between teeth, peridontal pockets
Small bowel
Colon
What are the positive effects of human colonic bacteria?
Synthesis and excrete vitamins Prevent colonisation by pathogens Kill non-indigenous bacteria Stimulate development of MALT Stimulate production of natural antibodies
What are the consequences of being ‘germ-free’?
Vitamin deficiencies
Increased susceptibility to infectious disease
Poorly developed immune system
Lack of natural antibody
Which bacteria notoriously forms endospores?
Clostridium tetani
A classic sore throat is caused by …
Strep viridans
Can gonorrhoea cause UTIs?
No
Can cause inflammation of the urethra
Describe the bacteria of the mouth
Lots of anaerobes
Over 700 species
Human bites can cause v nasty/fatal infections
Give some risk factors for oral thrush
Newborns Diabetes Antibiotics Inhaled steroids Immune deficiency
What is the treatment for oral thrush?
Amphotericin lozenges
Nystatin suspension
What is Ludwig’s angina?
Bugs at cervical lymph nodes in tissue of neck
Usually streptococcal
Need to act v quickly because can cause laryngeal oedema
Where are the 3 sites that are swabbed for MRSA?
Nose
Throat
Perineum
When is strep viridans likely to cause bacteriaemia?
Teeth brushing
Dental procedures
General anaesthesia
Define bacteriaemia
Bacteria are rapidly cleared from the bloodstream
No symptoms
Define septicaemia
Bacteria not cleared and multiply in the bloodstream
Sepsis symptoms develop
Is tonsillitis usually viral or bacterial?
Viral
What are the most common viral causes of tonsillitis?
Adenovirus
Rhinovirus
EBV
What is the most common cause of bacterial tonsillitis?
Strep pyogenes
What is quinsy?
Hugely inflamed tissue around the palatine tonsil
Deviates the uvula
Patient in absolute agony and struggling to breathe
Stop eating because swallowing is too painful
Treatment - to let the pus drain out
Why is the treatment for quinsy very dangerous?
Cutting into tonsil to let the pus drain out
Very close to the internal carotid artery
How many species of bacteria live in the colon?
> 100
What particular species of bacteria are most common in the colon?
Bacteroides
Clostridia
Name some bacteria always present in the colon
Bacteroides fragilis, bacteroides oralis, bacteroides melaninogenious
E-coli
Enterococcus faecalis
How do we describe any gut surgery?
Dirty surgery
How do we prevent surgical wound infections?
Prophylactic Abx
Metronidazole + broad spec Abx
Or
Co-amoxiclav
What is the purpose of anal glands?
Secrete mucus at dentate line to aid passage of faeces
How do we get perianal abscesses?
Stasis in the anal glands
Blockage causing infection
Describe lactobacillus and its useful effect
Normal vaginal commensal
Converts glycogen to lactic acid - maintain acidic environment of vagina
Prevents other bacteria and candida albicans form growing
Why is vaginal thrush common on broad spec Abx?
Kill lactobacillus in vagina
Acidic environment cannot be maintained
Candida albicans can grow
What is the commonest bacteria causing UTI?
E-coli
What is the second commonest organism causing UTI?
Enterococcus faecalis
What is crepitus of the skin?
Feeling air underneath the skin
