🦠 Microbiology Review for the MedTech Board Exam

What the Microbiology course covers

1. Unit 1: Bacteria & Stains

   Bacterial cell structure, growth needs, metabolism, and the stains that reveal them.

   The bacterial cell · Growth & metabolism · The Gram stain · Acid-fast & other stains

2. Unit 2: Normal Flora & Infection

   Who lives where in a healthy body, and how pathogens get in and cause disease.

   Normal flora · Defenses, virulence & spread

3. Unit 3: Specimens, Media & Safety

   Collecting and transporting specimens, choosing media, incubation, biosafety and sterilization.

   Collecting specimens · Transport & rejection · Culture media & incubation · Biosafety, sterilization & disinfection

4. Unit 4: Staphylococci & Micrococci

   Catalase-positive gram-positive cocci: S. aureus, the coagulase-negative staphylococci and look-alikes.

   Catalase-positive cocci · S. aureus: toxins & disease · Identifying S. aureus · Coagulase-negative staphylococci

5. Unit 5: Streptococci & Enterococci

   Catalase-negative cocci: hemolysis, Lancefield groups, key species and the tests that separate them.

   Hemolysis & grouping · Group A strep: S. pyogenes · Group B strep & groups C, G · Pneumococcus & viridans strep · Enterococcus & group D

6. Unit 6: Aerobic Gram-Positive Bacilli

   Listeria, Erysipelothrix, Corynebacterium, Bacillus, Nocardia and other aerobic gram-positive rods.

   Listeria & Erysipelothrix · Corynebacterium · Bacillus · Nocardia & other gram-positive rods

7. Unit 7: Neisseria & Moraxella

   Gram-negative diplococci: gonococcus, meningococcus and Moraxella catarrhalis.

   Neisseria gonorrhoeae · Meningococcus & Moraxella

8. Unit 8: Fastidious Gram-Negative Rods

   Haemophilus, Bordetella, Legionella, zoonotic coccobacilli and the HACEK group.

   Haemophilus · Bordetella & Legionella · Zoonotic coccobacilli · HACEK & other oral rods

9. Unit 9: Enterobacterales

   The enteric gram-negative rods: media, key biochemical tests and the major genera.

   Enteric basics & media · Biochemical tests · E. coli & the lactose fermenters · Salmonella, Shigella, Yersinia & Proteus

10. Unit 10: Curved Rods & Nonfermenters

    Campylobacter, Helicobacter, Vibrio and relatives, then Pseudomonas and other nonfermenters.

    Campylobacter & Helicobacter · Vibrio, Aeromonas & Plesiomonas · Pseudomonas & Burkholderia · Other nonfermenters

11. Unit 11: Anaerobes

    Anaerobic culture, the gram-negative anaerobic rods, Clostridium and Clostridioides, and anaerobic cocci.

    Anaerobic culture · Anaerobic gram-negative rods · Clostridium & Clostridioides · Non-spore-formers & anaerobic cocci

12. Unit 12: Mycobacteria

    Processing specimens for acid-fast bacilli, M. tuberculosis, TB testing and the nontuberculous mycobacteria.

    Processing & culture · M. tuberculosis & TB testing · Nontuberculous mycobacteria

13. Unit 13: Unusual Bacteria & Zoonoses

    Mycoplasma, Chlamydia, spirochetes, rickettsiae, zoonoses and agents of bioterrorism.

    Mycoplasma & Ureaplasma · Chlamydia · Spirochetes · Rickettsiae, zoonoses & bioterrorism

14. Unit 14: Susceptibility Testing & Molecular Methods

    How antibiotics work, standardized susceptibility tests, resistance mechanisms, and modern identification.

    Antibiotics & how they work · Disk diffusion & MIC · Detecting resistance · Modern identification

Sample Microbiology board exam questions

A few practice questions from the course, with explanations. Thousands more are in the app.

1. 1. A Gram stain of a known S. aureus control shows pink cocci, and the neutrophils on the same slide are pink. The most likely error is:

   1. Omitting the counterstain
   2. Over-decolorization
   3. Too thick a smear
   4. Under-decolorization
   Show answer

   Answer: B. Over-decolorization

   Gram-positive cocci losing the crystal violet means too much decolorizer; an under-decolorized smear would show purple host cells.

2. 2. Which isolate would be considered normal flora from a throat culture and not reported as a pathogen?

   1. Viridans streptococci
   2. Streptococcus pyogenes
   3. Corynebacterium diphtheriae
   4. Neisseria gonorrhoeae
   Show answer

   Answer: A. Viridans streptococci

   Viridans streptococci are the main oral flora; group A strep, C. diphtheriae and the gonococcus are always significant in the throat.

3. 3. A sputum Gram stain shows >25 squamous epithelial cells and <10 WBCs per low-power field. The lab should:

   1. Culture it anaerobically
   2. Report normal flora without plating
   3. Reject it and request a new specimen
   4. Culture it with full identification
   Show answer

   Answer: C. Reject it and request a new specimen

   Many squamous cells and few WBCs mean the sample is mostly saliva and will grow misleading mouth flora.

4. 4. Gram-positive cocci in clusters are catalase positive and slide coagulase negative. The next test should be:

   1. Tube coagulase
   2. Optochin
   3. PYR on the slide
   4. Bile esculin
   Show answer

   Answer: A. Tube coagulase

   Some S. aureus lack clumping factor; a negative slide test must be confirmed with the tube (free coagulase) test.

5. 5. A β-hemolytic, catalase-negative coccus from a throat swab is PYR positive and bacitracin susceptible. It is:

   1. Enterococcus faecalis
   2. Streptococcus agalactiae
   3. Streptococcus pyogenes
   4. Streptococcus dysgalactiae
   Show answer

   Answer: C. Streptococcus pyogenes

   Among β-hemolytic streptococci, PYR positivity identifies group A; enterococci are usually not β-hemolytic in the throat and are bacitracin resistant.

6. 6. A pregnant woman’s blood culture grows a small β-hemolytic gram-positive rod that is catalase positive and shows tumbling motility at room temperature. It is:

   1. Corynebacterium diphtheriae
   2. Erysipelothrix rhusiopathiae
   3. Streptococcus agalactiae
   4. Listeria monocytogenes
   Show answer

   Answer: D. Listeria monocytogenes

   Listeria is a small gram-positive rod that is catalase positive, shows narrow β-hemolysis, and tumbles at room temperature (umbrella motility in semisolid agar). Pregnant women are at risk from soft cheese or deli meat, and infection can harm the fetus.

7. 7. Oxidase-positive gram-negative diplococci from CSF produce acid from glucose and maltose. The organism is:

   1. Neisseria lactamica
   2. Moraxella catarrhalis
   3. Neisseria gonorrhoeae
   4. Neisseria meningitidis
   Show answer

   Answer: D. Neisseria meningitidis

   Neisseria identification uses sugar use: N. meningitidis makes acid from glucose and maltose, N. gonorrhoeae from glucose only, N. lactamica from glucose, maltose and lactose, and M. catarrhalis from none. Glucose plus maltose means meningococcus.

8. 8. A gram-negative coccobacillus from a child’s ear grows on chocolate agar, not blood agar, and grows only around a disk containing both X and V factors. It is:

   1. Haemophilus parainfluenzae
   2. Haemophilus influenzae
   3. Haemophilus ducreyi
   4. Moraxella catarrhalis
   Show answer

   Answer: B. Haemophilus influenzae

   H. influenzae needs both X factor (hemin) and V factor (NAD). Chocolate agar supplies both. On plain media it grows only where an X+V disk provides them. H. parainfluenzae needs V only; H. ducreyi needs X only.

Practice more Microbiology questions

How you review in MedTech Reviewer

• Learning path: short lessons, each followed by questions, with a checkpoint at the end of every unit.
• Spaced repetition: questions you miss come back sooner, so key facts stick for exam day.
• Flashcards and timed quizzes in exam style, with an explanation for every answer.
• Board-readiness score per subject, so you know where to focus.
• Arcade games, PvP battles and Guilds to keep reviewing fun with classmates.

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