L 93 UTI

Question 1

When in life do males have a higher incidence of UTI than females?

Answer 1

Only in first few months of life and is generally due to congenital abnormalities.

Question 2

When in life do males and females begin to have an equal ratio of UTI’s?

Answer 2

Later in life after 50

Because males begin to have BPH which causes urinary stasis and leads to an increased risk of infection

Question 3

What is the primary source of bacteria for UTI’s?

Answer 3

Fecal bacteria

This is partly why females have a higher incidence of UTI’s

Question 4

What are the chances that a UTI is not ascending but somehow came from within the body?

Answer 4

There is a 5% chance that the infection is not ascending

Question 5

What are some factors that predispose women to UTI’s?

Answer 5

Shorter urethra
New sexual partner and being sexually active
Certain contraceptive methods like diaphragms and others
Pregnancy: blocks ureter, progesterone decreases valve muscle tone, hormones decrease peristalsis causing stasis
Menses: lose normal flora causing increased risk of E. coli, S. saprophyticus infection
Postmenopausal: decreased estrogen changes vaginal flora, bladder and uterine prolapse causing stasis

Question 6

What are some factors that predispose men to UTI’s?

Answer 6

Uncircumcised infants can have fecal contamination of the prepuce causing infection
New sex partner, anal sex
BPH

Question 7

What is an uncomplicated UTI?

Answer 7

UTI in otherwise healthy individual that is not pregnant and an adult
Everyone else is complicated

Question 8

What are the Enterobacteriacea?

Answer 8

These are the PESSKY Strains:
Enterobacter
Proteus
Escherichia
Shigella
Salmonella
Klebsiella
Yersinia
Citrobacter

Question 9

What are the two most common causative agents for UTI’s?

Answer 9

E. coli: g(-)

Staph. saprophyticus: g(+)

Question 10

Describe the fimbriae of E. coli and how they function as a virulence factor

Answer 10

E. coli has 2 kinds of fimbriae that act as adhesins and virulence factors:

1) Mannose-Sensitive or Type 1: bind to lower UT, bind mannose residues on proteins of the bladder, prescribing mannose may help eliminate these bacteria
2) P fimbria: assoc. with pyelonephritis (upper UT), bind P blood group antigens which are disaccharides found on surfaces of uroepithelial cells, they do not bind mannose

Question 11

Patient is found to have Struvite crystals on catheter. What virulence factor is responsible, what is the mechanism of crystal formation, and what are the organisms potentially responsible?

Answer 11

Struvite crystals are formed when Mg and Ph precipitate out of urine that has a higher pH than normal. This happens when the enzyme urease is present which hydrolyzes urea into ammonia. The organisms that have this enzyme are”
Staph. saprophyticus
Proteus mirabilis

Stones can also form in the kidney and ureter from this.

Question 12

What are some of the less common causative agents for UTI’s?

Answer 12

Enterococcus faecalis
Staph epidermidis
Proteus mirabilis
Klebsiella pneumoniae
Citrobacter

Question 13

Patient has an upper UTI and bacteria are found to be bound to P blood group antigens on the epithelial cells which is allowing a prolonged course of the infection. What is the virulence factor and the likely agent?

Answer 13

P fimbriae bind to the P blood group antigens on uroepithelial cells
This is a virulence factor of E. coli

Question 14

What virulence factor allows the swarming of bacteria and which bacteria are known to swarm?

Answer 14

Flagella allow the motility of bacteria which is needed for swarming to occur. The most talked about bac. in class that swarms is Proteus, but E. coli and Citrobacter also have flagella that allow for motility.

Question 15

Which virulence factor may help protect from phagocytosis and which agents have it?

Answer 15

Capsular K Antigen helps protect from phagocytosis and is only found on g(-) enterobacteriacea like E. coli

Question 16

If S. aureus or Salmonella are found to be the causative agents for the UTI, what route of infection is now more likely?

Answer 16

The majority of UTI’s are caused by ascending infections. However, it is possible to have a descending infection and these tend to be caused by S. aureus and Salmonella, but can also be from M. tuberculosis, and Candida

Question 17

Patient has dysuria, pyuria, hesitancy, and increased frequency of urine. They are found to be infected with a common STD. No flank pain or suprapubic tenderness or feverWhat is the likely diagnosis?

Answer 17

Urethritis is the likely diagnosis
This is a localized inflammation of the urethra and is not necessarily a UTI involving the bladder or kidneys
Can be concurrent with cystitis in females and prostatitis in males.
Often caused by STD’s

Question 18

Patient presents with bacteriuria, pyuria, suprapubic tenderness and hematuria. No flank pain or fever. What is the likely diagnosis?

Answer 18

Cystitis or lower UTI

This is localized to the bladder

Question 19

Patient presents with fever, malaise, N/V, and headache. Flank pain and CVA tenderness are present. WBC casts are seen in the urine. What is the likely diagnosis?

Answer 19

Pyelonephritis
This is an infection of the kidneys
Systemic Sx and casts are indicative of upper UTI

Question 20

What levels of bacteria are needed in the urine to diagnose a UTI?

Answer 20

Greater than 10^5 CFU/mL except for with S. aureus and Salmonella where any amount is enough for a diagnosis

Question 21

Hematuria is common in UTI’s, but what similar conditions do not have blood in the urine?

Answer 21

Urethritis

Vaginitis

Question 22

What agar is used to select for g(-) bacteria?

Answer 22

MacConkey Agar

Question 23

What is the purpose of CLED agar?

Answer 23

CLED agar is used because it lacks the necessary agents for Proteus to swarm

Question 24

What does a Kirby-Bauer test tell you?

Answer 24

tells susceptibility

Question 25

A patient is determined to have pyuria. What would have been found in the urine to indicate this diagnosis?

Answer 25

Leukocyte Esterase would have been present. This is an enzyme released by dead WBC’s

Question 26

What does the presence of Nitrate reductase in the urine tell you?

Answer 26

These are nitrates produced by E. coli, Proteus, Klebsiella

Question 27

Patient is treated with Nitrofurantoin. What condition did they likely have?

Answer 27

Uncomplicated Cystitis

Cystitis is usually treated for 3 days

Question 28

Patient has uncomplicated pyelonephritis and needs treatment. What drugs should be used and for how long?

Answer 28

Fluoroquinolones are commonly used for 10 day duration
Ciprofloxacin
Levofloxacin