Flashcards in Microbiology Deck (114)
Urine in what areas is usually sterile?
What microbes are commensals in the lower urethra?
Anaerobes (rarely cause UTI)
What is cystitis?
Infection in bladder (Lower UTI)
What is an upper UTI?
Infection involving ureters
What is pyelonephritis?
An upper UTI involving the kidneys
What is a complicated UTI?
UTI complicated by:
What effect does a complicated UTI have on treatment?
Requires a longer antibiotics course
When might bacteruria not be an infection?
In the elderly
Patients with catheters
Why are females much more prone to UTIs?
Short and wide urethra
Urethral opening close to anus
What can increase the risk of UTIs?
Why do posterior urethral valves increase the UTI risk?
Incomplete bladder emptying:
-> Urine stasis -> Infection
What is the most common route of UTI? What route does it take?
Bowel bacteria -> Perineal skin -> Lower urethra -> Bladder -> Ureters -> Kidneys
How can a descending UTI occur?
1. Patient with bacteraemia/sepsis
2. Bacteria seeded in kidney
3. Multiple small abscesses -> Bacteruria
What are coliforms?
Rod-shaped, gram negative, non-spore forming, facilitative anaerobes
What is the most common causal organism in UTIs?
E. coli (70%)
What other coliforms can cause UTIs?
What are Proteus sp. UTIs associated with? How do they cause this?
- Produce ureases
- Urea broken down into ammonia
- Urinary pH rises
- Precipitates salt formation
Proteus sp. UTIs have what other distinguishing feature?
What are Enterococcus sp?
Types of Strep. living in the GI tract
Which of the following is antibiotic sensitive and which can be resistant and difficult to treat:
- Enterococcus faecalis
- Enterococcus faecium
- Antibiotic sensitive
- Can be resistant and difficult to treat
Who gets UTIs caused by Staphylococcus saphrophyticus?
Women of child-bearing age
Why is Pseudomonas not a coliform?
What are Pseudomonas UTIs associated with?
Urinary tract instrumentation
What is the only antibiotic that can treat Pseudomonas UTIs and what does this increase the risk of?
- Increased risk of C. diff
What symptoms suggest an upper UTI?
What urine is likely to be infected in obtaining a urine sample?
1st urine (collects commensals from perineum and lower urethra)
What (ideally) needs to be carried out before obtaining a MSSU?
Wash perineum and urethral meatus with saline:
- Not antiseptic (May kill bacteria)
When would a clean catch urine sample be used?
In children and elderly when MSSU can't be obtained
In what individuals is a bag urine sample used?