Passmed - Microbiology Flashcards
Lymphocyte counts in
fungal meningitis
tuberculous (TB) meningitis
viral meningitis t
fungal meningitis 20 - 200 lymphocytes/mm³
tuberculous (TB) meningitis 30 - 300 lymphocytes/mm³
viral meningitis 15 - 1,000 lymphocytes/mm³
Microscopy of
S. pneumoniae N.meningitis L. monocytogenes E. coli H. influenzae Neisseria gonorrhoea Pseudomonas aeruginosa Staphylococcus aureus Group B streptococcus
S. pneumoniae - gram +ve diplococci/chain
N.meningitis - gram -ve diplococci
L. monocytogenes - gram +ve rod
E. coli - gram -ve rod
H. influenzae - gram -ve coccobacilli (short rods or ovals)
Neisseria gonorrhoea, a gram -ve diplococcus
Pseudomonas aeruginosa Gram -ve rods
Staphylococcus aureus Gram-+ve cocci
Group B streptococcus, a gram- +ve diplococcus
Human bite wounds mx
The correct answer is co-amoxiclav. With a human bite, antibiotics should be offered if a bite has broken the skin and drawn blood. This is not the case with the man in the scenario, but he has been bitten in what NICE guidelines denote as a ‘high-risk area’. High-risk areas include the hands, feet, face, genitals, skin overlying cartilaginous structures or an area of poor circulation. If a bite has broken the skin but not drawn blood, such as in this scenario, antibiotics should be considered if it is in a high-risk area or if the person is at high risk (immunosuppression, diabetes, asplenia or decompensated liver disease). The first choice antibiotic to be used in the prophylaxis and treatment of human and animal bites is co-amoxiclav.
Doxycycline with metronidazole would be the antibiotic of choice if the patient had a penicillin allergy or if co-amoxiclav is unsuitable.
Hep virus associated with shellfish and pork
Hepatitis E is associated with faecal-oral spread, commonly affecting shellfish and pork products. Blood results show elevated bilirubin and significant transaminitis.
Gold standard for HIV screening after a needlestick
The gold standard for screening is to do a combined HIV test (p24 antigen and antibody), both at 4 weeks (the earliest both tests may show a positive result) and at 3 months (the earliest both tests will definitely show a positive result)
Perform stool microbiological investigations if:
Perform stool microbiological investigations if:
1) You suspect septicaemia
2) there is blood and/or mucus in the stool or
3) the child is immunocompromised
Commonest bacterium causing LRTI in CF
Pseudomonas aeruginosa
treat with piperacillin with tazobactam or ciprofloxacin
When do the following infections start causing symptoms?
Staphylococcus aureus Escherichia coli Giardia Salmonella Shigella
Staphylococcus aureus severe vomiting after a short incubation period of 30 minutes to 8 hours. The symptoms usually resolve within two days.
Escherichia coli 3-4 days and causes diarrhoea that usually becomes bloody, lasting up to a week
Giardia watery diarrhoea at least 5 days after infection
Salmonella gastroenteritis is characterised by diarrhoea and fever, 6 hours and 6 days after infection.
Shigella 1-2 days after infection, fever alongside diarrhoea which is sometimes bloody
antibiotic of choice for neutropenic sepsis
Piperacillin with tazobactam (Tazocin)
This is typically commenced before neutropenia is confirmed on blood testing. Piperacillin is a penicillin, and therefore works by breaking down the peptidoglycan cell walls of bacteria. Tazobactam inhibits the breakdown of penicillins by bacterial β-lactamases, therefore preventing bacterial resistance to piperacillin when given in combination.
Common clinical feature in PCP
profound desaturation on exercise
clear chest
The first line treatment in amoebiasis is:
Metronidazole
