Question

and failure to properly cleanse the external genitalia (in female patients) prior to specimen collection are some of the ways in which specimens may become contaminated. in this case, the patient returned to provide another sample. instructions were provided again, and the patient was asked whether she understood what was required of her. this time the sample yielded only one species, escherichia coli, a bacterium that is a common causative agent of urinary tract infections. the patient was treated with antibiotics for 10 days, and a repeat culture was negative for any microorganisms.

concept check #1

1. when a urine sample reaches the laboratory, what is the first technique used to determine if a urinary tract infection exists?

∘ sample is allowed to sit for days to observe cloudiness
∘ sample is biochemically tested
∘ sample is grown on an agar plate
∘ sample is observed microscopically

1. it is normal to have a relatively large amount of bacteria in a clean catch sample.

(click to select) ▾

1. in the case, the patient is treated with antibiotics for her uti. this is because escherichia coli is a ______.

∘ virus
∘ helminth
∘ bacterium
∘ prion

1. why are urinary tract infections more common in women?

∘ only pregnant individuals can get utis
∘ they carry more fecal bacteria
∘ the female urethra is shorter than the male urethra
∘ their vaginal tract is highly acidic

Explanation:

Question 1

To determine if a urinary tract infection (UTI) exists, the first technique for a urine sample in the lab is to grow it on an agar plate (culture) to see if bacteria grow. Let's analyze the options:

• "Sample is allowed to sit for days to observe cloudiness" is incorrect as it's not a standard first technique.
• "Sample is biochemically tested" is not the first step for UTI detection (usually done after culture or microscopy, but culture is more initial for identifying pathogens).
• "Sample is grown on an agar plate" is correct because culturing the sample on agar helps identify if pathogenic bacteria (like Escherichia coli) are present, which is a key step in UTI diagnosis.
• "Sample is observed microscopically" can be done, but culturing is often the first step to isolate and identify the organism.

A clean - catch urine sample should have very few or no bacteria if there is no infection. So the statement "It is normal to have a relatively large amount of bacteria in a clean catch sample" is false.

The case states that Escherichia coli is a bacterium. Let's analyze the options:

• "virus" is incorrect as E. coli is not a virus.
• "helminth" is incorrect as helminths are parasitic worms, and E. coli is a bacterium.
• "bacterium" is correct as per the given case description.
• "prion" is incorrect as prions are misfolded proteins, and E. coli is a bacterium.

Answer:

C. Sample is grown on an agar plate

Question 2