Microbiology for Primary Care

Question 1

What are the commonest causative organisms in urinary tract infections?

Answer 1

• Gram negative bacilli

- E. Coli

Question 2

In a urinary tract infection what are the most likely urinalysis findings?

Answer 2

Blood
Protein -inflammatory response
Nitrites - produced by bacterial nitrite reductase

Question 3

Describe the appropriate management of a urinary tract infection.

Answer 3

Empirical antibiotic therapy to cover most likely organisms and that have good urine bioavailability.

Trimethoprim, nitrofurantoin, amoxicillin.

Treat for 3 days in uncomplicated female cases and 7 days in males, diabetics, pregnancy, recurrent UTI, over 65 years and children.

Send urine for MC&S if absent or poor response to initial antibiotic therapy.

Question 4

Describe a typical case of pyelonephritis.

Answer 4

• Recent previous or current urinary infective symptoms
• Feels generally unwell
• Nausea + vomitting
• Fever +/- rigors
• Flank pain

Clinically:

• Tachycardia
• Hypotension
• Fever
• Signs of dehydration

Question 5

What are the common causes of gastroenteritis?

How would you distinguish between the two?

Answer 5

Salmonella
Abdo pain mild and colicky. diarrhoea NOT blood stained.

Campylobacter
Abdo pain more severe and constant. diarrhoea blood stained.

Question 6

How can microbiological causes of gastroenteritis be diagnosed?

What organisms are routinely tested for?

Answer 6

Stool sample for microscopy

• Samlonella
• Shigella
• Campylobacter
• E. Coli
• Cryptosporidium parvum (Using modified Zeihl-Neilson or auramine stain)

Question 7

What effect can antibiotics have in patients with E.Coli assoicated gastroenteritis?

Answer 7

Increased risk of haemolytic ureamic syndrome as antibiotics cause rupture of organisms and release of toxin which worsens the outcome.

Question 8

Patients with absent /dysfunctional spleens are at risk of infections by which organisms?

Answer 8

• Streptococcus Pneumoniae
• Neiserria meningitidis
• Haemophillus influenza
• Malaria

Question 9

What is an appropriate prophylactic antibiotic therapy following exposure to a patient with Neisserria Meningitidis?

Answer 9

Licensed Option:
Oral rifampicin - 2 day course

Unlicensed Options:
Single dose of oral ciprofloxacin
Single does of IM ceftriaxone