deck_1559553 Flashcards
Where can the largest population of bacteria be found in the GI tract?
Colon
What are the beneficial roles that the normal flora found in the body can have?
– synthesise and secrete vitamins e.g. K, B12 and thiamine– prevent colonisation by pathogens– kill non-indigenous bacteria– stimulate MALT (mucosa associated lymphoid tissue) development in cecum and Peyer’s Patches– stimulate the production of normal antibodies
What are the two main shapes of bacteria?
BacilliCocci
What is meant by the term obligate aerobes?
Bacteria which must have oxygen in order to survive e.g. pseudomonas and mycobacterium TB
What is meant by the term obligate anerobes?
Bacteria which will die in the presence of oxygen e.g. bacteriodes fragilis and clostridial organisms.
Give a particular characteristic of clostridia
Form protective spores which are able to survive in an oxygenated environment.
What is the most common bacterial in the colon?
Bacteriodes fragilis
What is meant by faculative anaerobes?
Prefer oxygen, but can live without it e.g. gram negative enteric bacteria such as E coli and gram positive skin dwellers such as staphylococcus
Where are the anaerobic zones in hte GI tract?
Small bowelColonParts of the mouth – tongue, deep in the taste buds, in the biofilm between the teeth and in peridontal pockets in people with peridontal disease.
Give some gram positive aerobic cocci
StaphylococciStreptococciEnterococci
Give some gram negative aerobic cocci
Neisseria meningitidisNeisseria gonorrhoeae
Give some gram positive aerobic bacilli
Corynebacterium – diptheriaBacillus – anthraxLactobacilliMycobacterium tuberculosis
Give some gram positive anaerobic bacilli
Clostridia– tetani– perfringens– difficile
Give some gram negative aerobic enteric bacilli
E coliPseudomonasProteusKlebsiellaSalmonellaShigellaVibrio choleraeCampylobacterHelicobacter pylori
Give some gram negative aerobic non-enteric bacilli
Haemophilis influenzaeBordetella pertussisBrucella
Give some gram negative anaerobic bacilli
Bacteroides fragilis
Where do you normally find gram negative bacteria present?
In the lower bowel
What colour will gram negative bacteria be stained?
Red
What colour will gram positive bacteria be stained?
Blue
How do bacteria colonise in the body?
Slime biofilm Pili form attachments to cells
What is the main type of bacteria found in the mouth?
Anaerobic bacteria
What are the main types of bacteria found in the mouth?
StreptococciStaphylococciCandidaLactobacillusEnterococcus
What effects does streptococci have in the mouth?
Streptococcus mutans causes dental caries and gingivitisAlso Ludwig’s angina which is cellulitis occurring in the throat which can compromise the airways
What effects does staphylococci have in the mouth?
Staphylococcus aureaus can cause parotitis
WHat effects does candida have in the mouth?
Oral thrush – caused by candida albicans
What causes candida infections to occur?
Usually is after a course of antibiotics which kill the bacteria in the mouth, allowing candida to grow.
In which groups of people does candida commonly occur?
NewbornsDiabetic patientsAsthmatic patients (local immunodeficiency due to steroids)People with immune deificiencies
What effects does lactobacillus have in the mouth?
Leads to dental caries and tooth decay
What effects does enterococcus have in the mouth?
Can cause tissue destruction in patients who are:Malnourished, dehydrated and immunocompromised. Tissues destruction is known as Noam or Cancrum Oris.
What is the treatment for Candida infections?
Amphotercin and nystatin suspension
What bacteria are commonly found in the nose?
Staphylococcus Streptococcus
Where are the three sites for MRSA screening swabs?
NoseThroatPerineum
Why are certin sites used fro MRSA screening?
The three sites are where the staphylococci bacteria are usually found
What commonly causes tonsilitis?
Viruses cause 70% of the cases on tonsilitisStrep. pyogenes does cause the other 30%
What are the bacteria that are always present in the throat?
Streptococcus viridansStaphylococciNeisseria meningitidis
Where is lactobacilli usually found?
Vagina– makes it acidic so that candida albicans cannot grow
What does heamophilus influenzae cause?
Community acquired pneumonia and epiglotitis
What does streptococcus pneumoniae cause?
Community acquired pneumonia
When does streptococcus viridans cause infections?
It can enter the blood during teeth brushing, dental procedures and general anaesthesia. From here, it can stick to prostheses
Give some examples of prostheses
Heart valvesOrthopaedic implantsVascular grafts
Define bacteraemia
Bacteria enter the blood and are rapidly cleared from the blood stream. Do not develop symptoms
Define septicaemia
Bacteria enter the blood and are not cleared. They multiply in the blood stream and a patient will present with sepsis symptoms
What are the symptoms of sepsis?
Temperature 38Increased HRIncreased respiratory rateWhite Blood Count (12x10^9/L)– a probable or confirmed infection
What are the main viruses that cause tonsillitis?
AdenovirusRhinovirusEpstein-Barr virus
What can tonsillitis lead to?
Quinsy – abscess in tonsil.Must remove pus to relieve symptoms
What is oesophageal candidiasis?
When candida albicans moves down the throat into the oesophagus
What proportion of people are infected with helicobacter pylori?
About 50%
How many people infected with helicobacter pylori get gastric or duodenal ulcers?
10-20%
How do you treat gastro-duodenal ulcers?
PPIss AntacidsAntibiotics
What bacteria are always present in the colon?
Bacteroides fragilisBacteroides oralisBacteroides melaninogenicusE coli Enterococcus faecalis
What are the top two causes of UTIs?
E coli then Enterococcus faecalis
When do you perform surgery on the small bowel?
When there are abnormal bacteria in the small bowel
What is the name given to surgeries of the small bowel and why?
Dirty surgery– there is a high risk of wound infection
What measures can be take to try and prevent post-operative infections for small bowel surgeries?
Prophylactic antibiotics– metronidazole– a broad spectrum anticiotic e.g. gentamicin or cephalosporin
What is faecal peritonitis?
Inflammation of the peritoneum due to the presence of faeces in the peritoneal cavity.
Why does faecal peritonitis occur?
Perforation of the sigmoid colon
What is the outcome for faecal peritonitis?
Has a high mortality rate in young, healthy people. This is due to the high numbers of bacterium free in the peritoneum
What are perianal abscesses?
Abscesses which occur in the glads in the anal canal which usually produce mucus for lubrication to help in passing faeces.
What is lactobacillus?
A gram positive bacteria which is mormaly present in the vaginal flora
What does lactobacilllus do?
Converts glycogen into lactic acid which prevents colonisation by candida albicans
What would the growth of candida albicans in the vagina give rise to?
Thrush
What can lead to vaginal thrush?
A course of broad spectrum antibiotics which will kill the natural flora in the vagina
What colonic bacteria can survive on perineal skin?
E coliEnterococcus faecalisLactobacilusThese will all move around
What do more UTIs occur in women?
Shorter distance between the anus and the urethra compared to men
What is a particular characteristic of pseudomonas?
Loves fluid and is able to colonise the legs
What type of bacteria is E coli?
Gram negative aerobic bacilus
What type of bacteria is Enterococcus faecalis?
Gram positive anaerobic bacillis
What are the three clostridia bacteria found in the colon?
TetaniDifficilePerfringens
What does clostridium tetani cause?
Tetanus– Muscle spasms– Occurs in adults who have not been vaccinated– Ricus sardonicus
What clostridium difficile cause?
Psaeudomembranous colitis– sever inflammation of the colon– tends to occur after antibiotic treatment– produces spores (present in hospitals)
What does clostridium perfringens cause?
Gas or wet gangrene– anaerobic digestion of glucose produces ethanol and CO2– digests away the muscles, producing a toxin which is highly susceptible to the heart and can cause cardiac arrest
What is the main cause for GI infections?
When the ecology of the normal gut flora is disrupted, usually after a treatment of antibiotics.
What are the symptoms of noro-virus?
Short period of vomiting and diarrhoeaHeadachePainful stomach crampingFeverAching limbs
What causes gastroenteritis?
Food or drink which has been contaminated with organisms or toxins. Causes vomiting and diarrhoea
How can identify the cause of gastroenteritis be deduced?
Toxins tend to have a much quicker onset and length of illness – a few hours after eatingOrganisms as the cause tend to occur about 48 hours after ingestion.
What are the most common organisms that cause gastroenteritis?
SalmonellaCampylobacterLitsteria
Describe cholera
Is a severe acute infection. Caused by Vibrio cholerae which survives in water supplies.
What are the effects of cholera?
Has a specific effect on the ileum– leads to massive movement of water and salt into the lumen by active secretion.
What are the main complications of cholera?
Dehydration from sever diarrhoea
What is a characteristic sign of cholera?
Rice-water appearance diarrhoea– made up of intestinal secretions and mucus
What are some parasites that have an effect on the GI tract?
Giardia and cryptosporidium cause gastroenteritis. Helminths cause malabsorption
What is the main cause of traveller’s diarrhoea?
Enterotoxinogenic E coli– causes by heat stable or labile toxins. – leads to severe, cholera-like water diarrhoea
What are the main things that cause intestinal bowel inflammation?
Inflammatory bowel disease– ulcerative colitis– chrons disease– diversion colitis– diverticular colitis– radiation– drugs– Ischaemic colitis
