RMA Microbiology and Specimen Collection 1 — Questions and Answers

Question 1: Which type of microorganism is responsible for the majority of urinary tract infections (UTIs)?

Viruses
Fungi
Bacteria (Correct answer)
Parasites

Correct answer: Bacteria

The vast majority of UTIs are caused by bacteria, most commonly Escherichia coli, which accounts for approximately 80–85% of community-acquired UTIs.

Bacterial UTIs are among the most common infections encountered in medical office settings. Escherichia coli (E. coli) from the patient's own gastrointestinal flora is responsible for the majority of community-acquired UTIs. Other bacterial causes include Staphylococcus saprophyticus (particularly in young sexually active women), Klebsiella pneumoniae, Proteus mirabilis, and Enterococcus faecalis. Fungal UTIs (Candida) occur primarily in immunocompromised patients or those with urinary catheters. Medical assistants collect urine specimens for culture, perform dipstick urinalysis, and must understand the microbiology of UTIs to assist with appropriate specimen handling.

Question 2: What is the purpose of a culture and sensitivity (C&S) test?

To determine the patient's blood type and Rh factor
To identify the causative organism of an infection and determine which antibiotics will be effective (Correct answer)
To measure the concentration of antibodies in the blood
To detect the presence of cancer cells in a tissue sample

Correct answer: To identify the causative organism of an infection and determine which antibiotics will be effective

A culture and sensitivity test identifies the specific microorganism causing an infection (culture) and then tests which antibiotics are effective at killing or inhibiting it (sensitivity/susceptibility testing).

A culture and sensitivity (C&S) test is a two-part microbiological test. The culture portion involves growing the microorganism from a clinical specimen (urine, wound swab, sputum, blood) on a culture medium to identify the specific pathogen. The sensitivity (or antimicrobial susceptibility testing) portion then exposes the isolated organism to various antibiotics to determine which drugs inhibit its growth (susceptible), which have borderline effectiveness (intermediate), and which do not work (resistant). This guides targeted antibiotic therapy and helps prevent antibiotic resistance. Medical assistants must collect C&S specimens correctly to ensure accurate results.

Question 3: A throat swab for a rapid strep test should be collected by swabbing which area?

The roof of the mouth and hard palate
The front of the tongue and lips
The posterior pharynx and tonsillar areas (Correct answer)
The inside of each cheek

Correct answer: The posterior pharynx and tonsillar areas

For a throat culture or rapid strep test, the swab must be applied firmly to the posterior pharynx (back of the throat) and tonsillar areas or any visible exudate or inflamed areas.

Proper throat swab technique is essential for accurate streptococcal detection. Using a sterile swab and a tongue depressor (to avoid contamination from the anterior mouth), the medical assistant should swab the posterior pharyngeal wall and both tonsils (or tonsillar fossae) using a firm, rolling motion. Areas of exudate, inflammation, or ulceration should be specifically targeted. Avoiding the anterior mouth, tongue, and uvula prevents contamination with oral flora that can cause false-positive or false-negative results. Group A Streptococcus (Streptococcus pyogenes) is the primary target of rapid strep testing.

Question 4: Which personal protective equipment (PPE) is required when handling potentially infectious specimens in a medical office?

Surgical cap and shoe covers only
Gloves and a face shield only if splashing is likely
Gloves at minimum; additional PPE based on risk assessment (Correct answer)
N95 respirator and full gown at all times

Correct answer: Gloves at minimum; additional PPE based on risk assessment

Standard precautions require gloves when handling any potentially infectious material. Additional PPE (gown, mask, eye protection) is used based on the risk of splash or aerosol exposure.

Standard Precautions, mandated by OSHA's Bloodborne Pathogens Standard, require healthcare workers to treat all human blood and body fluids as potentially infectious. At minimum, gloves must be worn when handling any specimen that could contain blood or body fluids. Additional PPE is required when the risk of splashing, spraying, or aerosolization of infectious material exists — for example, a gown and face shield when processing urine or blood cultures. Medical assistants must apply and remove PPE in the correct sequence to prevent self-contamination and ensure compliance with infection control standards.

Question 5: What is the correct way to label a specimen container before collection?

Label it after collection once the patient has left
Label it in the collection room immediately after the specimen is obtained (Correct answer)
Pre-label it before the patient arrives and verify at the time of collection
Have the patient label their own container to ensure accuracy

Correct answer: Label it in the collection room immediately after the specimen is obtained

Specimen containers should be labeled immediately after collection in the presence of the patient, after the specimen has been obtained, to ensure correct patient-to-specimen identification.

Proper specimen labeling is critical for patient safety and diagnostic accuracy. Best practice and CLSI guidelines specify that specimen containers should be labeled in the presence of the patient, immediately after the specimen is collected. The label must include the patient's full name, date of birth (or medical record number), date and time of collection, and the collector's initials. Pre-labeling containers before collection increases the risk of mislabeling (using the wrong pre-labeled tube). Labeling after the patient leaves also increases risk. Medical assistants are responsible for accurate specimen labeling as part of the pre-analytical phase of laboratory testing.

Question 6: What does 'gram-positive' mean when bacteria are classified by Gram stain?

The bacteria have a higher growth rate than gram-negative organisms
The bacteria retain the crystal violet dye and appear purple under the microscope (Correct answer)
The bacteria have a double cell membrane that makes them harder to treat
The bacteria are resistant to all common antibiotics

Correct answer: The bacteria retain the crystal violet dye and appear purple under the microscope

Gram-positive bacteria retain the crystal violet dye used in Gram staining due to their thick peptidoglycan cell wall layer, appearing purple or dark blue under the microscope.

The Gram stain is one of the most fundamental tests in microbiology. In the procedure, bacteria are stained with crystal violet, treated with iodine (to fix the dye), decolorized with alcohol or acetone, and then counterstained with safranin (pink/red). Gram-positive bacteria (like Staphylococcus and Streptococcus) have a thick peptidoglycan cell wall that retains the crystal violet-iodine complex after decolorization, so they appear purple. Gram-negative bacteria (like E. coli and Klebsiella) have a thin peptidoglycan layer and an outer membrane that does not retain the violet dye; they are decolorized and then stained pink by safranin. This distinction is clinically important because gram-positive and gram-negative bacteria respond differently to antibiotics.

RMA Microbiology and Specimen Collection 1

Which type of microorganism is responsible for the majority of urinary tract infections (UTIs)?