Urinary Tract Infections

What are the two types of UTIs?

Cystitis and pyelonephritis

Define cystitis

Bladder infection

Define pyelonephritis

Kidney infection

What is the most common route of infection for a UTI?

Ascending route

What are risk factors for UTIs?

Gender (females)

Age (elderly)

Urologic abnormalities

Urinary tract catheter, instrumentation

Pregnancy

SGLT2 inhibitor

What is the most common bacteria that causes UTIs?

Escherichia coli (75-95%)

What are signs and symptoms of cystitis?

Dysuria

Frequency/urgency

Hematuria

What are signs and symptoms of pyelonephritis?

Costovertebral angle tenderness

Fever

What symptom will not appear in cystitis?

A patient CANNOT have fever in cystitis since it is isolated to the bladder

Fever indicates pyelonephritis

What laboratory test is used for cystitis?

Urinalysis (often not needed in young, non-pregnant females)

Which laboratory tests are used for pyelonephritis?

Urinalysis

Urine culture

Blood cultures are also often considered!

How should a urinalysis (UA) be taken?

Clean catch = mid-stream (preferred)

Define pyuria in a urinalysis

> 5-10 WBC in the urine

Describe the presence of squamous cells in the urine

NONE to MINIMAL

Describe the WBC/hpf in a "positive" UA

50

Describe the WBC/hpf in a normal UA

0-5

Describe the leukocyte esterase content in a "positive" UA

3+

Describe the leukocyte esterase content in a normal UA

0

Describe the squamous cell content in a "positive" UA

< 1

Describe the squamous cell content in a normal UA

None

Define bacteriuria

Presence of bacteria in urine

Define UTI

Signs and symptoms of UTI

What must be distinguished between when considering if a patient has a UTI?

Must distinguish between asymptomatic bacteriuria AND infection

Describe the diagnosis of asymptomatic bacteriuria

NO signs or symptoms of UTI with bacteriuria

Should asymptomatic bacteriuria be treated or routinely screened for?

NO, unless a special case

In which cases should asymptomatic bacteriuria be treated or routinely screened for?

Pregnancy

Prior to invasive urinary tract procedures

Prior to renal transplantation (and within 30 days of transplant)

Is antimicrobial therapy usually indicated in asymptomatic bacteriuria?

Not usually indicated (must have symptoms for treatment!)

When should you screen an elderly patient with AMS for a UTI?

If they have urinary symptoms, otherwise, look for other causes first!

Ex: dehydration, medications, environment

How long should asymptomatic bacteriuria be treated in pregnancy?

4-7 days

What is the treatment for asymptomatic bacteriuria in pregnancy?

Beta-lactams for 5-7 days

Most-commonly prescribed

Which antibiotics should be avoided in pregnancy?

Fluoroquinolones

Tetracyclines

What are signs of an uncomplicated UTI?

Local bladder s/s

No fever

No other signs of systemic infection

No flank pain

Are urine cultures often performed in uncomplicated UTIs?

No, diagnosis typically based on symptomatology alone

What are first line empiric treatments for uncomplicated UTIs?

Macrobid 100 mg BID x 5 days

Fosfomycin 3 g PO x 1 dose

TMP/SMX 1 tab BID PO x 3 days

Cephalexin or Augmentin PO x 3-7 days

What is an alternative empiric treatment for uncomplicated UTIs?

Ciprofloxacin or levofloxacin PO x 3 days

What are fosfomycin and nitrofurantoin used for?

Antimicrobial agents for cystitis ONLY!!

What is the MOA of fosfomycin?

Cell wall synthesis inhibitor

Prevents building of peptidoglycan

What is the MOA of nitrofurantoin?

Not well-characterized

Damages bacterial DNA

What bacteria does fosfomycin have activity against?

E. coli

Pseudomonas aeruginosas

Has activity against some ESBL-producing Gram-negative bacteria

Describe the dosage form of fosfomycin

3 gram oral powder in a sachet

Mix in 3-4 ounces of cold water

What is the dose of fosfomycin in uncomplicated cystitis?

3 grams PO x 1 dose

What bacteria does nitrofurantoin have activity against?

E. coli

What are the two dosage forms of nitrofurantoin?

MacroBID = BID

Macrodantin = QID

When should the use of nitrofurantoin be avoided and why?

Avoid in patients with CrCl < 30 mL/min

Increased risk for treatment failure and adverse effects

Which antibiotics do not concentrate well in the urine and therefore should not be used in uncomplicated UTIs?

Moxifloxacin

Clindamycin

Macrolides

What are some other common antibiotics used for uncomplicated UTIs?

Beta-lactams = cephalexin, amoxicillin-clavulanic acid

Which antibiotics are not recommended for empiric therapy in uncomplicated UTIs?

Ciprofloxacin, levofloxacin

What are signs of a complicated UTI?

Fever signs/symptoms of systemic illness

Flank pain

What is an example of a complicated UTI?

Pyelonephritis

Which patients are likely to get a complicated UTI?

Patients with urinary catheters

Patients with neurogenic bladder, urinary obstruction, or urinary retention as an underlying condition

What is the four step approach to empiric antibiotic treatment for a complicated UTI?

1. Assess severity of illness

2. Risk factors for resistance

3. Patient-specific considerations

4. If septic, consider the antibiogram

What are the three categories of illness severity when assessing a complicated UTI?

1. Sepsis with or without shock

2. Without sepsis, IV route of therapy

3. Without sepsis, oral route of therapy

If a patient is septic with shock, what antibiotic should be chosen from the antibiogram?

Choose antibiotic > 90% susceptible

If a patient is septic without shock, what antibiotic should be chosen from the antibiogram?

Choose antibiotic > 80% susceptible

What is the option for IV empiric therapy in a complicated UTI in most patients?

Ceftriaxone

What antibiotics can be considered for IV empiric therapy in a complicated UTI in patients with a history of Pseudomonas?

Piperacillin-tazobactam

Cefepime

What antibiotics can be considered for IV empiric therapy in a complicated UTI in patients with a history of ESBL OR Pseudomonas?

Carbapenems

What antibiotics should be avoided for IV empiric therapy in a complicated UTI?

Fluoroquinolones, if possible

What antibiotics are options for PO empiric therapy in a complicated UTI?

Cephalexin

TMP/SMX

Amoxicillin-clavulanate

Describe targeted treatment in a complicated UTI

De-escalation/streamlining based on the urine culture identification and susceptibility results

Attempt to select the narrowest spectrum antibiotic that is susceptible if possible

When should a patient with a complicated UTI be assessed for a switch to PO antibiotics?

If septic shock or sepsis that is now resolved and patient is clinically improving

What is the treatment duration for a complicated UTI?

7 days

Describe catheter-associated UTIs

Common healthcare-associated infection

Catheter disrupts host defense mechanisms & provides easier access of uropathogens to the bladder

Describe the diagnosis of catheter-associated UTIs

Signs and symptoms of UTI among a catheterized patient

Describe the management of catheter-associated UTIs

REMOVE catheter if indicated

REPLACE if indicated

How should a urinalysis and urine culture be performed in a catheter-associated UTI?

Should be performed off of "clean urine" from the newly replaced catheter, NOT the older catheter

Which patients should be treated for catheter-associated UTIs?

Treat only symptomatic patients

In whom are Enterococcus spp. UTIs common?

In patients with indwelling Foley catheters

Often a colonizer

What are the agents of choice for an Enterococcus spp. UTI?

Ampicillin/Amoxicillin

Describe Staphylococcus aureus in the urine

NOT a common urinary pathogen and SHOULD NOT be isolated in a urine culture

What is the MOA of phenazopyridine?

Local urinary analgesic/anesthetic

What is an important counseling point of phenazopyridine?

Will discolor urine (orange), can stain

What is a concern regarding UTI prophylaxis?

Concern for the development of antibiotic resistance

What agent can be used for UTI prophylaxis and why?

Methenamine

Bacteria do not develop resistance because methenamine is an antiseptic

What is the MOA of methenamine?

Broken down to ammonia & formaldehyde in acidic urine