Lecture 12 Flashcards
What is the major cause of Hospital Acquired urinary tract infections?
Catheters
What are the causes of community acquired urinary tract infections?
Prostate problems in males and the proximity effect in females
What is the proximity effect?
Females have a higher incidence rates of UTIs than males as the urethra is closer to faecal origin
What is the major pathogen causing urinary tract infections?
Escherichia Coli
What are the risk factors for a urinary tract infection?
Sexually active women, Previous infection, Underlying disease leading to stasis of urine
What are the key virulence factors of E.Coli?
Pili, Iron acquisition, Lipid A, Toxins for cell death, Intracellular bacterial comunity (strands), Quiescent intracellular reservoir
What are the pili of E.Coli used for?
P-Pili are used to adhere to the kidney,
Type 1 pili are used to adhere to the bladder,
both types of pili help the microorgansim avoid getting washed away
What is the shape of E.Coli?
E.coli is a gram negative rod
What is cystisis?
A relatively less serious condition, but may progress up the urinary tract to cause the more serious pyelonephritis
What is pyelonephritis?
Inflammation of the kidneys
How can E.Coli be diagnosed?
Dipstick test, Cysteine-Lactose-Electrolyte deficient agar
How does the dipstick test work?
Tests for nitrites, Leukocyte esterase, pH, Red blood cells, Protien and glucose levels
What can be learned from the cysteine lactose electrolyte deficient agar?
As E.Coli is a lactose fermenter it will appear yellow, BUT Klebsiella also turns positive
What microorganisms that cause urinary tract infections test negative for the CLED agar?
Pseudomonas, Proteus
What is the purpose of the ImViC test?
To distinguish between E.Coli and Klebsiella
What does the ImViC test use?
Indole (break down of tryptophan) Methyl Red (fermentation of glucose) Vogues Proskauer (Butenyl glycol production from glucose) Citrate
What are the ImViC test results for E.Coli?
Positive for Indole and methyl Red, negative for Vogues Proskauer and Citrate
(Pink, Red Light Brown, Green)
What are the ImViC test results for Klebsiella?
Negative for Indole and methyl red, positive for Vogues Proskauer and Citrate
(Pale with yellow upper layer, yellow, brown precipitate, blue)
What are the treatment options for E.Coli that do not involve antibiotics?
Fluids and pain relief, good hygiene practices may need to be reinforced, cranberry juice, and yoghurt can help promote the growth of good bacteria to crowd out the infection while mannose tablets may inhibit the pathogen in some cases
When should antibiotics be considered with urinary tract infections?
If the disease is prolonged or progresses to more severe symptoms
This can also be identified by enumeration of more than 10^8CFU/L
What antibiotics can be used against E.Coli?
Amoxicillin (Penecillin Based), Trimethoprim (Inhibits folic acid synthesis), Ciprofloxacin (inhibits DNA replication)
What is ESBL E.Coli?
E.Coli that have resistance to all penicillin based antibiotics due to a beta lactamase enzyme
How can ESBL E.Coli be treated?
Use of polymyxin B or E or cationic polypeptide antibiotic used as a last resort as these antibiotics can be damaging but maybe the only thing that works
