Body Sites (Urine) Flashcards
A microorganism responsible for causing infection or infectious disease
Etiologic agent
A person who harbors the etiologic agent but shows no apparent signs or symptoms of infection or disease
Carrier
The origin of the etiologic agent or location from which it disseminates (e.g., water, food, insects, animals, other humans)
Reservoir
Infections acquired as a result of a medical procedure
Health care–associated infection (HAI)
Infection for which the etiologic agent was acquired in a hospital or long-term health care center or facility
Nosocomial infection
Microorganisms that cause infections or disease
Pathogen
Organism’s ability to cause disease
Pathogenicity
Measure or degree of pathogenicity of an organism
Virulence
Characteristics that enable pathogens cause disease
Virulence factors
Organisms which cause infection when one or more of the host’s defense mechanisms are disrupted or malfunction
Opportunistic pathogens
Microorganisms that inhabit many surfaces of the human body
- Colonizers, Normal flora, and Transient microbiota
- Are collectively known as the….
Human microbiome
The persistent survival of microorganisms on a surface of the human body (with no clinical expression, no immune response)
Colonization
______ are able to survive, but do not multiply, on the surface and are frequently shed with the host cells.
Transient colonizers
______ not only survive but also thrive and multiply; their presence is more persistent.
Resident microbiota
The establishment of a long-lasting, mutually beneficial or harmless relationship between a colonizer and the human host
Possible role of colonizing organisms
The first step in the process for the development of infection and disease.
Possible role of colonizing organisms
Balance between the normal human microbiome and the appearance of a potentially infectious agent.
Host-pathogen relationship
Host factors + Environment + Virulence factor
Host-pathogen relationship
Among the most common bacterial infections that lead patients to seek medical care.
UTI
Who has a higher incidence of UTI?
Women
What factors make women more susceptible to UTIs?
- Short urethra in close proximity to perirectal region,
- Sexual intercourse ↑ contamination of the female urethra.
- Anatomic + hormonal changes favor the development of UTIs
What makes older men more susceptible to UTIs?
Enlarged prostate prevents bladder from emptying.
What are the routes of transmission for UTI?
Ascending, hematogenous, and lymphatic
Does urine north of the urethra contain natural flora?
No; urine is sterile
What do we call normal flora that we see in voided urine? Where does it actually reside in the body?
Urogenital flora; comes from the epithelium at the distal end if the urethra
What percentage of patients with catheters will develop a UTI?
Up to 20% of patients with catheters will develop a UTI
What are three physical properties that act as a defense against UTIs?
- Normal voiding of urine
- Valve-like mechanism that prevents backward flow
- Uroendothelial cells that initiate an immune response
What are three chemical properties of urine that act as defense against UTIs?
- High osmolality, Low pH
- High urea content
- High organic acid content
Isolation of bacteria without signs of infection
Increases with age!
Asymptomatic bacteriuria
Cystitis
Infection of the bladder
- Primarily in young, sexually active women
- Symptomatic; few isolated organisms (<105 CFU/mL)
Acute urethral syndrome
Inflammation of kidney parenchyma, calices, & pelvis
Pyelonephritis
What percentage of sepsis originates from the urinary tract?
25% - called urosepsis
What is urethritis usually caused by?
An STD - specifically GC
The following conditions are what? Underlying disease Sickle Cell anemia Diabetes Kidney stones Structural abnormalities of Urinary tract Indwelling catheters Neurogenic bladder
Risk factors for complicated UTIs
Which common UTI pathogen uses adhesins to facilitate bacterial adhesion?
Uropathogenic E. coli (UPEC)
Which common UTI pathogen hydrolyzes urea, which then increases pH and creates an environment favoring the formation of kidney stones?
Proteus spp.
Which common UTI pathogen adheres to the uroepithelial cells?
S. saprophyticus
In what time frame should a urine culture be delivered to the lab?
Within two hours
Name the urine sample type described. Least invasive/ Periurethral area is cleansed before collecting a midstream urine
Clean-catch midstream urine (CCMS)
Name the urine sample type described. Urine considered uncontaminated
Straight catheterized urine (“In and Out.”)
Name the urine sample type described. Specimen collected from a catheter port, not the collection bag!
Indwelling catheter collection
Name the urine sample type described. Most Sterile;
A syringe is used to obtain urine from the bladder.
Only acceptable urine specimen for Anaerobic culture!
Suprapubic bladder aspiration
Name the urine sample type described. When the patient doesn’t have a bladder, they have an nephrostomy.
Nephrostomy and Illeal Conduit
May include exam of centrifuged sediment of urine for enumeration of PMNs
Microscopic Urinalysis
What specific UTI organism is a nitrate reductase test good for detecting?
Enterobacterales
What is a leukocyte esterase test good for detecting?
Inflammatory cells - correlates with hemocytometer counts for pyuria
Is a gram stain best for detecting microbes in low or high numbers?
Higher numbers (> or = to 10^5 cfu/mL)
T or F. You centrifuge urine before making a gram stain.
False
How do we gram stain urine?
Using a 0.01 mL loop, transfer well-mixed urine onto a slide and let air dry without spreading.
When is doing a gram stain from a urine sample most useful for the clinician?
When a patient may have acute pyelonephritis, an invasive UTI, or other patients for whom immediate information is necessary for appropriate clinical management.
When should you add a CNA or PEA plate for a urinary culture?
Include CNA or PEA when the culture has two types of infections and you need to make sure the gram pos isn’t being masked by gram neg - also used when there’s a straight cath sample.
For plating urine, how much does the calibrated loop deliver? How much growth does 1 colony represent?
0.001 mL or 1 uL; 1,000 CFU/per mL
For plating urine from a suprapubic aspirate, how much does the calibrated loop deliver? How much growth does 1 colony represent?
0.01 mL or 10 uL; 100 CFU/per mL
What 5 organisms (or groups of organisms) require susceptibility testing?
- Enterobacterales
- Pseudomonas and other NonFermementers
- S.aureus
- CNS, not S. saprophyticus
- Enterococcus sp. from inpatients or surgical urology
