GI 9 infection Flashcards
What are the different types of anaerobes?
Obligate and facultative - Obligate die in the presence of oxygen. Facultative prefer oxygen but can live without it e.g.. many gram-neg enteric bacteria such as E. Coli and gram-pos skin dwellers such as Staphylococcus
Where are the anaerobic zones in the GIT?
Parts of the bout - on the tongue deep in tast buds, fluid films including biofilm between teeth, gingival crevice areas and in people with peridontal disease they live in peridontal pockets
Small bowel
Colon
How were mitochondria developed in evolution?
At some stage an aerobic bacterium was taken into an anaerobic bacterium and formed an organelle which later became a mitochondrium
What do human colonic bacteria do?
Synthesize and excrete vitamins that are absorbed by host. Vit K, B12, thiamine and many other Bs.
Prevent colonisation by pathogens
kill non-indignous bacteria
Stimulate development of MALT (in caecum and Peyer’s patches)
Stimulate production of natural antibodies
What problems do ‘germ-free’ animals develop?
Vitamin deficiencies, esp K and B12
Increased susceptibility to infectious disease
Poorly developed immune system, esp in GIT
Lack of natural antibody or natural immunity to bacterial infection
What are the 2 common endospores?
Bacilus anthrax
Clostridium tetani
How do E coli stick to the bladder wall?
Using pili
What are the common anaerobes in the mouth?
Streptococci staphylococci candida lactobacius enterococcus 700 species therefore human bite can be fatal
WHat is Noma/cancrum oris?
Mouth bacteria can cause tissue destruction if individual is malnourished, dehydrated, immunocompromised or systemically unwell
What microorganism causes oral thrush?
Candida albicans
What are the risk factors for oral thrush?
Newborns Diabetes Antibiotics Inhaled steroids Immune deficiency
What is the treatment for oral thrush?
Amphotericin lozenges
Nystatin suspension
What causes dental caries/gingivitis?
The teeth are colonised by the mouth bacteria plus Strptococcus mutans
What usually causes Ludwig’s angina?
Usually strptococcal
What microorganism usually causes parotitis?
Staph aureus
What are the 2 common bacteria in the nose?
Staphylococcus
Streptococcus
(many others)
What are teh 3 sites for MRSA screening swabs?
Nos, throat and perineum
What microorganisms are always in the throat?
Strep viridans
Staphylococci
Neisseria meningitidis
WHat other microorganisms are common in the throat?
Strp pyogenes Strep pneumoniae Haemophilus influenzea Lactobacilli Corynebacterium diptheria Candida albicans
What is the significance Strep viridans?
Non-pathogenic throat commensal
During procedures such as teeth brushing, dental procedures and general anaesthesia, may enter blood stream
May stick to prostheses such as heart valves, vascular grafts, orthopardic implants and cause infection. Prostheses don’t have the anti-bacterial sticking armour that cells have
What is the difference between bactereamia and septicaemia?
Bacteraemia - the bacteria are rapidly cleared from the bloodstream (by liver/spleen macrophages). No symptoms produced
Seticaemia - bacteria are not cleared, multiply in the blood stream. Sepsis symptoms develop
What microorganisms commonly cause tonsillitis?
70% viral - andenovirus, rhinovirus, Epstein-barr
30% bacterial mainly Strp pyogenes (Beta-haemolytic)
What is quinsy?
Complication of tonsillitis. Collection of pus develops between the back of one of your tonsils and the wall of your throat
What is oesophageal candidiasis?
Opportunistic infection of the oesophagus by candida albicans. Usually in immunocompromised patients
