Microbiology Flashcards
Which is the best specimen to send to the Microbiology lab to screen for sexually transmitted infections in a 20 year old asymptomatic female who attends her GP practice?
- endocervical swab for chlamydia/gonococcal PCR
- vulvovaginal swab for chlamydia/gonococcal PCR
- first pass urine specimen for chlamydia/gonococcal PCR
- vulvovaginal swab for chlamydia/gonococcal culture
- vulvovaginal swab for chlamydia PCR
Vulvovaginal swab for chlamydia/gonococcal PCR - less invasive, same result and quicker than endocervical
Metronidazole is the treatment of choice for which of the following infections?
- Candida and bacterial vaginosis
- Trichomonas vaginalis and Candida
- Treponema pallidum and Trichomonas vaginalis
- Bacterial vaginosis and Trichomonas vaginalis
- Bacterial vaginosis and Treponema pallidum
Bacterial vaginosis and Trichomonas vaginalis - BV is caused by Gardnerella vaginalis, and Trichomonas is a flagellated protozoan parasite, both of which are anaerobic and are treated with Metronidazole
Which of the following statements about Chlamydia trachomatis is true?
- has a cycle of reproduction that takes around 20 minutes to complete under ideal culture conditions
- serotypes L1, L2 and L3 are associated with Lymphogranuloma Venereum infection in MSM
- Serotypes A, B and C are associated with most genital Chlamydia infection in the UK
- it is a virus that can only reproduce inside a host cell
- it usually presents as an acute urethritis in men
Serotypes L1, L2 and L3 are associated with Lymphogranuloma Venereum infection in MSM
A-C are associated with eye infections
D-K are associated with genital infections
L1-L3 are associated with LGV (proctitis, type of chlamydia that attacks lymph nodes. Usually diagnosed in MSM and has a high risk of concurrent STIs, such as HIV)
Which of the following genital infections is indicated by the presence of “Clue Cells” on microscopy?
- bacterial vaginosis
- Candida albicans
- Trichomonas vaginalis
- Treponema pallidum
- Gonorrhoea
Bacterial vaginosis - Gardnerella vaginalis is associated with Clue Cells
Which of the following statements about Neisseria gonorrhoeae is true?
- the increase in antimicrobial resistance as resulted in a test of cure being advised in all patients
- it usually causes a clear watery urethral discharge in men
- it is a gram positive diplococcus
- phrayngeal gonorrhoea usually presents as a nasty throat infection
- neutrophil polymorphs have difficulty phagocytosing N. gonorrhoeae
The increase in antimicrobial resistance as resulted in a test of cure being advised in all patients
N. gonorrhoeae is gram negative dipolococci like 2 kidney beans facing each other
Gonorrhoeal throat infections don’t produce symptoms in 90% of patients
Which of the following statements about N. gonorrhoeae infection is true?
- Oral ciprofloxacin is the current recommended treatment
- Oral azithromycin is the current recommended treatment
- Oral cefixime is the current recommended treatment
- Oral cefixime and azithromycin is the current recommended treatment
- IM ceftriaxone and oral azithromycin is the current recommended treatment
IM ceftriaxone and oral azithromycin is the current recommended treatment - NB - JUST IM CEFTRIAXONE, azithromycin has been removed from the protocol due to fears of resistance
Which of the following statements about coliforms is true?
- Pseudomonas aeruginosa is a type of coliform
- Most coliforms are sensitive to amoxicillin
- Enterococcus faecalis is a type of coliform
- Most coliforms are sensitive to metronidazole
- Most coliforms are sensitive to gentamicin
Most coliforms are sensitive to gentamicin
Pseudomonas aeruginosa is a gram-negative rod
Enterococcus faecalis is a gram-positive coccus formally classified as part of the Group D Streptococcus system
Coliforms are rod-shaped, gram-negative, non-spore forming bacteria which can ferment lactose (“dirty bacteria”). Examples - Enterobacter, Escherichia, Klebsiella, Citrobacter
What is the recommended empirical antibiotic treatment for a patient with suspected intra-abdominal sepsis who has a normal renal function and is not hypersensitive to penicillin?
- Amoxicillin and metronidazole
- Co-amoxiclav and clarithromycin
- Co-trimoxazole, gentamicin and metronidazole
- Amoxicillin, gentamicin and metronidazole
- Co-trimoxazole and metronidazole
Amoxicillin, gentamicin and metronidazole
Amox - covers gram positives
Metro - covers anaerobes
Gent - covers gram negatives
Which of the following statements about the diagnosis of sepsis/septic shock s true?
- in order to make a diagnosis of sepsis, a patient must have a SIRS plus confirmed positive microbiology
- low blood pressure is diagnostic of septic shock
- low blood pressure that does not come back up when IV fluids are given is diagnostic of septic shock
- patients who have pancreatitis and positive SIRS criteria probably have an infection/abscess developing
- patients with a low white cell count are very unlikely to have sepsis
low blood pressure that does not come back up when IV fluids are given is diagnostic of septic shock
Which is the most likely cause of bacterial meningitis in a previously healthy young adult in the UK?
- Neisseria meningitides
- Strep pneumoniae
- Listeria monocytogenes
- Group B strep
- Haemophilus influenzae type B
N. meningitides
NB - Strep is probably most likely overall, but be aware of N. meningitides in young adults
Which of the following statements is true?
- steroids are best given with or just before the first dose of antibiotics if they are indicated in a patient with bacterial meningitis
- almost all patients who have meningitis have a haemorrhagic rash
- there is no effective vaccine against some of the common strains of meningococcal infection seen in the UK
- if you suspect a patient has a meningococcal infection, antibiotics should NOT be given until CSF has been taken off
- a high lymphocyte count in CSF indicates bacterial meningitis
steroids are best given with or just before the first dose of antibiotics if they are indicated in a patient with bacterial meningitis
Which of the folllowing statements is true?
- aciclovir is useful for treating most causes of viral meningitis
- Listeria is a small, gram negative bacteria
- Gentamicin has good penetration into CSF and is useful for treating some types of meningitis
- Listeria infection is associated with the consumption of soft cheese
- Listeria meningitis is commonest in older children and young adults
Listeria infection is associated with the consumption of soft cheese
Most viral meningitides are not caused by HSV, so aciclovir isn’t very useful
Listeria is a gram positive flagellated bacterium
Why is ceftriaxone chosen for empirical treatment for suspected bacterial meningitis instead of penicillin?
- ceftriaxone has a longer half life
- ceftriaxone penetrates the CSF better
- most bacteria that cause meningitis are now resistant to penicillin
- resistance is less likely to emerge during ceftriaxone therapy
- ceftriaxone also has activity against Listeria
ceftriaxone has a longer half life (penicillin would have to e given 4 times a day) - NB, ceftriaxone also penetrates the CSF better than penicillin!
In Listeria infections are suspected, patients are given amoxicillin
If after 3 doses of gentamicin a patient isn’t responding, what medication do you switch to?
Aztreonam - used primarly to treat gram-negative infections
What diagnosis would the following CSF picture make you think of?
Cells - 101-103 (lymphocytes)
Gram stain for bacteria - negative
Bacterial antigen detection - negative
Protein g/l - normal or slightly high
Glucose mmol/l - usually normal
Viral meningitis
