Bacteriolgy pt 2

Of course! Here’s an expanded revision flashcard set in a regular Q&A format. You can use these for self-study, print them, or copy them into a document.

Clinical Bacteriology Flashcards

1. Vibrio Species

Q: What is the Gram stain and shape of Vibrio species?
A: Gram-negative, curved rod.

Q: Which species of Vibrio causes cholera?
A: Vibrio cholerae.

Q: What is the main virulence factor of Vibrio cholerae?
A: Cholera toxin (CTX), which causes massive watery diarrhea ("rice-water stools").

Q: What special media is used to culture Vibrio species?
A: TCBS agar (Thiosulfate Citrate Bile Salts Sucrose).

Q: Which sugar does Vibrio cholerae ferment on TCBS agar?
A: Sucrose (produces yellow colonies).

Q: What are the main symptoms of Vibrio parahaemolyticus infection?
A: Watery diarrhea, abdominal cramps, nausea, and sometimes vomiting.

Q: How is Vibrio vulnificus infection acquired?
A: Through contaminated seafood (raw oysters) or seawater exposure (wound infections).

Q: Which Vibrio species is associated with wound infections and sepsis in immunocompromised patients?
A: Vibrio vulnificus.

Q: What is the oxidase test result for Vibrio species?
A: Oxidase-positive.

Q: What is the treatment for severe cholera?
A: Oral rehydration therapy (ORT) and, in severe cases, tetracyclines (e.g., doxycycline).

2. Aeromonas & Plesiomonas

Q: What is a distinguishing feature of Aeromonas species?
A: Gram-negative, facultative anaerobic rod, oxidase-positive.

Q: Which diseases are caused by Aeromonas species?
A: Gastroenteritis, wound infections, and septicemia.

Q: How is Aeromonas transmitted?
A: Through contaminated water or food, and exposure to freshwater environments.

Q: What is the oxidase result for Aeromonas?
A: Oxidase-positive (like Vibrio).

Q: How is Plesiomonas shigelloides different from Aeromonas?
A: Plesiomonas is oxidase-positive but ferments glucose and does not grow in high salt, unlike Vibrio.

Q: What infections does Plesiomonas shigelloides cause?
A: Gastroenteritis (diarrhea) and opportunistic systemic infections.

3. Non-Glucose Fermenting Gram-Negative Bacteria

Q: What is a key feature of non-glucose fermenting Gram-negative rods?
A: They do not ferment glucose but can oxidize other sugars.

Q: Name two important non-glucose fermenting Gram-negative rods.
A: Pseudomonas aeruginosa, Acinetobacter baumannii.

Q: What is the oxidase test result for Pseudomonas aeruginosa?
A: Oxidase-positive.

Q: What is a characteristic pigment produced by Pseudomonas aeruginosa?
A: Pyocyanin (blue-green pigment).

Q: What type of hemolysis does Pseudomonas aeruginosa show on blood agar?
A: Beta-hemolysis (clear zones around colonies).

Q: Which infections are caused by Pseudomonas aeruginosa?
A: Pneumonia (especially in cystic fibrosis), wound infections, urinary tract infections (UTIs), and sepsis.

Q: Why is Pseudomonas aeruginosa difficult to treat?
A: Innate antibiotic resistance and ability to form biofilms.

Q: What is the oxidase test result for Acinetobacter baumannii?
A: Oxidase-negative (unlike Pseudomonas).

Q: Where is Acinetobacter baumannii commonly found in hospitals?
A: In ventilators, catheters, and intensive care unit (ICU) environments.

Q: Which bacterial genus is known for causing ventilator-associated pneumonia (VAP) in ICU patients?
A: Acinetobacter baumannii.

Q: What is the treatment challenge with Acinetobacter baumannii?
A: Highly antibiotic-resistant, often requiring colistin or carbapenems.

Q: How is Burkholderia cepacia complex relevant in clinical settings?
A: Causes respiratory infections in cystic fibrosis (CF) patients.

Q: Which test differentiates Burkholderia cepacia from Pseudomonas aeruginosa?
A: Oxidase test (Burkholderia is variable, Pseudomonas is always positive).

4. Laboratory & Antibiotic Susceptibility Testing

Q: What is the purpose of the Kirby-Bauer disk diffusion test?
A: To determine bacterial susceptibility to antibiotics.

Q: Which method provides the most precise antibiotic susceptibility data?
A: Minimum Inhibitory Concentration (MIC) testing.

Q: What does a positive catalase test indicate?
A: The presence of the enzyme catalase, which breaks down hydrogen peroxide (e.g., Staphylococcus, Pseudomonas).

Q: What is the most common nosocomial (hospital-acquired) pathogen in burn wounds?
A: Pseudomonas aeruginosa.

Q: Which organism is most commonly associated with "hot tub folliculitis"?
A: Pseudomonas aeruginosa.

5. Infection Control & Antibiotic Resistance

Q: What is the most effective infection control measure for preventing bacterial spread in hospitals?
A: Proper hand hygiene.

Q: What is the role of antibiotic stewardship programs?
A: To promote rational antibiotic use, reduce resistance, and improve patient outcomes.

Q: What does "intrinsically resistant" mean in terms of bacterial resistance?
A: A bacterium naturally lacks susceptibility to a class of antibiotics (e.g., Pseudomonas aeruginosa is intrinsically resistant to many β-lactams).

Q: Why is polymyxin (colistin) used as a last-resort antibiotic?
A: Due to its toxicity (nephrotoxicity, neurotoxicity) and the need to treat multidrug-resistant Gram-negative infections.

Q: What is the preferred treatment for Vibrio vulnificus septicemia?
A: Third-generation cephalosporins (e.g., ceftriaxone) plus doxycycline.

Q: What is the primary way to prevent cholera outbreaks?
A: Improving water sanitation and providing oral cholera vaccines.

Q: What are ESBL-producing bacteria?
A: Extended-Spectrum Beta-Lactamase (ESBL) producers, resistant to third-generation cephalosporins.

Q: How can carbapenem-resistant Enterobacteriaceae (CRE) infections be treated?
A: Colistin, tigecycline, or newer beta-lactam/beta-lactamase inhibitor combinations.