microbiology practicals - sem 2 Flashcards
how can bacterial meningitis cause symptoms such as severe headache, nausea and vomiting
strong inflammatory response –> pus –> blocks various foramina –> increased intracranial pressure
what is the commonest cause of meningitis
viruses
what are the 3 major bacteria causing acute meningitis and what are their characteristic gram stains
Haemophilus influenza B - small gram negative rods Strep pneumonia - gram positive diplococci Neisseria meningitidis - grave negative cocci in pairs
how does the determination of protein, glucose and leucocytes help in the management of acute meningitis
gives you an indication whether the infection is viral or bacterial or fungal
what rapid diagnostic tests are used in the diagnosis of meningitis
gram stain slide agglutination with latex beads covered with Ab PCR
when should a patient be started on treatment with meningitis
as soon as it is suspected
what is the antibiotic treatment for the major causes of bacterial meningitis
3rd generation cephalosporin such as cefitriaxone
which organism is the fine petecial rash assocaited with
N. meningitidis
Why is CSF inoculated into serum broth when testing for meningitis
patient may have been given antibiotics prior to LP - and therefore very hard to gram stain. However if just one bacterium is left it will grow overnight in serum broth and therefore can isolate the organism easier
which common cause of meningitis is imperative that AB susceptibility testing is performed
Strep pneumonia - increasing prevalence to beta-lactams (by mutating beta-lactam binding protein)
what is the AB that is “added in” for treatment of Strep pneumonia meningitis
Vancomycin
What is the characteristic gram stain of Strep B aggolacti
gram positive cocci in long chains
What is the current course for prevention of birth transmitted gram negative bacteria to babies (that would cause meningitis)
screen mother between 35-37 weeks gestation –> if positive –> give AB 4 hours before delivery
what is the commonest cause of viral meningitis
enterovirus
what types of things can determine disease prevalence
- climate/geography - vectors, reservoirs - weather - wealth of community - hygiene, sanitation, vaccination programs - length of stay - local agriculture and animal husbandary
parasitic infections are particularly prevalent in which type of travellers
those returning from the tropics
how do you diagnose parasitic infection in a returned travellor
- blood (thick and thin films) - blood for serology - faeces - sticky tape to perianal area - skin snips, biopsy specimens
what do you use thick and thin blood films for
thick - trypanosomiasis and filariasis thick and thin films for malaria
what is the gold standard for diagnosis of eukaryotic parasites
visualising them micro/macroscopically
infections in travellers fall into what 3 broad categories
common infections exotic infections emerging or re-emerging infections
how can a hookworm infection lead to anaemia
hookworm attaches to intestinal wall –> bleed
in what stage of the life cycle does hookworm infect humans
semi-matured hookworm that lives in soil –> penetrates bare feet
in what stage of the life cycle does hookworm make you ill
when it matures into adult worm and attaches to the intestinal wall
how do you diagnose hookworm
eggs in faeces
