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1

Case 1: A 24 y/o female has sexual intercourse with her fiancé. She usually urinates right after sex, but is too tired and goes to sleep instead. About 24-36 hours later she experiences dysuria (painful urination), urinary frequency and malodorous urine. She goes to her PCP and gives a urine sample which shows a lot of WBCs and grows Escherichia coli. She is placed on Ciprofloxacin for treatment.

Case 1: A 24 y/o female has sexual intercourse with her fiancé. She usually urinates right after sex, but is too tired and goes to sleep instead. About 24-36 hours later she experiences dysuria, urinary frequency and malodorous urine. She goes to her PCP and gives a urine sample which shows a lot of WBCs and grows Escherichia coli. She is placed on Ciprofloxacin for treatment.

2

Where did the E. coli come from?

Her GI tract. E. Coli is the second most common normal flora in the GI

3

How did the E. coli reach her urinary tract and
bladder?

Translocation to the urinary tract and entered the bladder through the urethra by swimming because uropathogenic E. Coli (UPEC) are motile

4

Would it be unusual to detect some E. coli in her urine?

No, the diagnosis of a UTI is based not the simple presence of flora but the elevated NUMBER.

5

Did it make a difference that she did not urinate after sex?

Yes, it flushes the area

6

Is there a downside to treating with Cipro?

she could get a yeast infection and gram negative rods like E. Coli can develop multi-drug resistance (mechanism: efflux pump)

C

7

What are some possible side-effects of Cipro (and Fluoroquinolones in general)

spontaneous tendon rupture (like Achilles tendon) and spontaneous retinal detachment. These drugs should be used sparingly because of these side effects and the potential for multi-drug resistance to develop

8

What is cystitis?

Cystitis is the result of the ascension of normal flora bacteria from the urethra to the bladder. Because the urethra is shorter in women and near the vagina and anus, UTIs are more common in women

9

What bacteria are the major causes of UTIs in women?

E. coli cause 90% of UTIs in women, but Klebsiella, Proteus, Enterococci, and Staph saprophyticus also cause UTIs.

UTIs keep slutty sorority pledges engaged

10

T or F. In elderly men and women, bacteriuria occurs more equally.

T. NOT UTIs, just the presence of bacteria

11

What are some common symptoms of bacteriuria?

pain while urinating (dysuria), frequent but low volume urination, suprapubic pain, and blood in the urine (hematuria). Most patients are afebrile

12

What does febrile mean?

showing a fever

13

What is pyelonephritis?

it basically means that the bacteria have made their way to the kidney

14

What should you suspect is a patient presenting with symptoms of a UTI are febrile?

if febrile, an upper UTI (pyelonephritis) should be considered.

15

T or F. The bladder has normal flora.

F. The bladder is normally sterile

16

In WOMEN, what density of bacteria per ml is needed to diagnose UTI?

greater than 10^5/ml

17

In MEN, what density of bacteria per ml is needed to diagnose UTI?

greater than 10^3/ml

18

What are two alternatives for UTI treatment?

Cipro is the go-to but resistance is rising. an alternative is Cotrimoxazole (Trimethoprim-Sulfamethoxazole) OR third-generation cephalosporins

19

When you see a UTI what should your first thought be in terms of bacteria?

E. Coli BUT Staph saprophyticus (if its gram-positive) is common!!

20

What are some characteristics of uropathogenic E. Coli (UPEC)?

1. they are facultative gram negative rods

2. they grow aerobically and ferment lactose (i.e. positive on an EMP plate)

3. found normally in the gut GI

21

What can uropathogenic E. Coli (UPEC) do in relation to nitrate? Why is this important?

convert it to nitrite. This is important because urine dipstick can detect the presence/ratio of nitrate to nitrite as a potential diagnosing factor

22

T or F. Only E. Coli that pick up a PAI are going to cause disease

T. Symptom presentation depends on what kinds of virulence factors are picked up

23

What kinds of virulence factors do UPEC bugs have?

1. Flagella that allow for movement

2. Type 1 fimbriae mediate attachment in lower UTI-bladder- (regulated by phase variation)

3. P fimbriae mediate attachment in upper- kidney and ureter- UTI (receptor is same as P blood group antigen)

24

Case 2
• A 70 y/o female presents to the ED with shortness of breath and wheezing. She has been hospitalized 5 times in the last 2 years with similar presentations. PMH includes COPD. She smokes 2 ppd and has for 50 years. Admission vitals: T 98.6°F, BP 120/76, HR 100, RR 30, O2 saturation 85% on RA. Her labs are unremarkable and chest x ray was clear.
• She is admitted and placed on oxygen by nasal cannula and nebulizer treatments for a COPD exacerbation, however she soon develops worsening respiratory failure and has to be intubated and placed on a ventilator. Her oxygenation initially improves over the next few days.
On day 5 of hospitalization, she develops increased O2 requirements, thick tracheal secretions, and a fever to 102°F. Labs show a WBC count of 15,000. CXR shows infiltrates. She is started on Vancomycin but does not improve.

• A sputum sample is sent to the lab. You are notified that there is growth on the agar plate, so you go down to look at it. You notice that it has a fruity odor. Here is what the plate looks like:
• Sputum culture grows Pseudomonas aeruginosa.

Case 2
• A 70 y/o female presents to the ED with shortness of breath and wheezing. She has been hospitalized 5 times in the last 2 years with similar presentations. PMH includes COPD. She smokes 2 ppd and has for 50 years. Admission vitals: T 98.6°F, BP 120/76, HR 100, RR 30, O2 saturation 85% on RA. Her labs are unremarkable and chest x ray was clear.

• She is admitted and placed on oxygen by nasal cannula and nebulizer treatments for a COPD exacerbation, however she soon develops worsening respiratory failure and has to be intubated and placed on a ventilator. Her oxygenation initially improves over the next few days.

On day 5 of hospitalization, she develops increased O2 requirements, thick tracheal secretions, and a fever to 102°F. Labs show a WBC count of 15,000. CXR shows infiltrates. She is started on Vancomycin but does not improve.

• A sputum sample is sent to the lab. You are notified that there is growth on the agar plate, so you go down to look at it. You notice that it has a fruity odor. Here is what the plate looks like:
• Sputum culture grows Pseudomonas aeruginosa.

25

What is the normal WBC count?

~3000-8000

26

What is the normal respiratory rate (RR)?

12-16. RR is the breaths taken in a minute

27

In general terms, what type of infection is this?
i?

opportunistic, nosocomial

28

How would you know this is a good sputum sample and not just saliva?

FYI: sputum is a mixture of saliva and mucus coughed up from the respiratory tract, typically as a result of infection or other disease and often examined microscopically to aid medical diagnosis.

you want to see few epithelial cells from saliva and more PMNs as a sign of infection

29

Nosocomial pneumonias are most often caused by G- rods or Staph. How might Pseudomonas (a G- rod) be distinguished from E. coli?

lactose fermentation (pseudomonas does not!!), oxidase positive vs negative

30

Why was the patient immediately started on Vancomycin? Why didn’t she improve?

Vancomycin was administered assuming they were treating the Staph (a gram positive strain- and a very common cause of nosocomial infection- so this isn't the worst assumption but wrong here).

So she didn't improve because Vanco doesn't cover gram-neg (which it probably will), or anaerobes