- Which of the following is a characteristic of Gram-negative bacilli?
- a) Thick peptidoglycan layer
- b) Presence of an outer membrane containing lipopolysaccharides (LPS) ✅
- c) Absence of a cell wall
- d) Production of endospores
- Which Gram-negative bacillus is commonly associated with urinary tract infections (UTIs)?
- a) Staphylococcus aureus
- b) Escherichia coli ✅
- c) Streptococcus pyogenes
- d) Bacillus subtilis
- What distinguishes Pseudomonas aeruginosa from other Gram-negative bacilli?
- a) Ability to ferment lactose
- b) Production of blue-green pigments ✅
- c) Resistance to oxygen
- d) Lack of flagella
- Which Gram-negative bacillus is known for causing whooping cough?
- a) Haemophilus influenzae
- b) Legionella pneumophila
- c) Bordetella pertussis ✅
- d) Klebsiella pneumoniae
- Which Gram-negative bacillus is most often linked to gastroenteritis due to contaminated food and water?
- a) Clostridium difficile
- b) Helicobacter pylori
- c) Salmonella enterica ✅
- d) Bacillus anthracis
- What test is primarily used to differentiate lactose-fermenting Gram-negative bacilli from non-lactose fermenters?
- a) Catalase test
- b) MacConkey agar ✅
- c) Coagulase test
- d) Oxidase test
- Which of the following Gram-negative bacilli is a common cause of hospital-acquired infections, especially in immunocompromised patients?
- a) Enterobacter cloacae ✅
- b) Mycobacterium tuberculosis
- c) Streptococcus pneumoniae
- d) Bacillus cereus
- Which Gram-negative bacillus is the most common cause of traveler's diarrhea?
- a) Escherichia coli ✅
- b) Shigella dysenteriae
- c) Vibrio cholerae
- d) Yersinia pestis
- What is the primary mode of transmission for *Legionella pneumophila*, a Gram-negative bacillus that causes Legionnaires' disease?
- a) Person-to-person contact
- b) Ingestion of contaminated food
- c) Inhalation of aerosolized water droplets ✅
- d) Direct contact with infected soil
- Which of the following Gram-negative bacilli is associated with peptic ulcer disease and gastric cancer?
- a) Campylobacter jejuni
- b) Klebsiella oxytoca
- c) Helicobacter pylori ✅
- d) Proteus vulgaris
- What is a common characteristic of the Enterobacteriaceae family of Gram-negative bacilli?
- a) Ability to form spores
- b) Facultative anaerobes ✅
- c) Strict aerobes
- d) Lack of a cell wall
- Which Gram-negative bacillus is characterized by a "safety pin" appearance on microscopy?
- a) Yersinia pestis ✅
- b) Escherichia coli
- c) Vibrio cholerae
- d) Salmonella typhi
- What is the primary virulence factor of Vibrio cholerae, the causative agent of cholera?
- a) Cholera toxin ✅
- b) Endotoxin
- c) Lecithinase
- d) Capsule
- Which Gram-negative bacillus is frequently implicated in infections in patients with cystic fibrosis?
- a) Haemophilus influenzae
- b) Klebsiella pneumoniae
- c) Pseudomonas aeruginosa ✅
- d) Neisseria gonorrhoeae
- Which of the following is true about *Shigella* species?
- a) They are motile with peritrichous flagella.
- b) They are lactose fermenters.
- c) They are primarily spread via the fecal-oral route. ✅
- d) They are spore-forming bacteria.
- Which of the following Gram-negative bacilli is known for causing typhoid fever?
- a) Escherichia coli
- b) Salmonella typhi ✅
- c) Pseudomonas aeruginosa
- d) Haemophilus influenzae
- Which Gram-negative bacillus is responsible for causing plague?
- a) Yersinia pestis ✅
- b) Vibrio cholerae
- c) Klebsiella pneumoniae
- d) Neisseria meningitidis
- Which of the following is a common virulence factor of *Escherichia coli* that causes diarrhea?
- a) Shiga toxin ✅
- b) Cholera toxin
- c) Botulinum toxin
- d) Diphtheria toxin
- Which Gram-negative bacillus is associated with the development of meningitis in children?
- a) Streptococcus pneumoniae
- b) Haemophilus influenzae ✅
- c) Staphylococcus aureus
- d) Mycobacterium tuberculosis
- Which of the following Gram-negative bacilli is known for causing foodborne illness through the production of heat-stable enterotoxins?
- a) Clostridium perfringens
- b) Bacillus cereus
- c) Staphylococcus aureus
- d) Escherichia coli ✅
- Which Gram-negative bacillus is commonly found in the human gut and is a major cause of sepsis in neonates?
- a) Klebsiella pneumoniae ✅
- b) Pseudomonas aeruginosa
- c) Salmonella enterica
- d) Yersinia enterocolitica
- Which of the following Gram-negative bacilli is known for causing urinary tract infections (UTIs) and is often resistant to multiple antibiotics?
- a) Proteus mirabilis
- b) Enterococcus faecalis
- c) Enterobacter cloacae ✅
- d) Streptococcus agalactiae
- Which Gram-negative bacillus is responsible for causing the sexually transmitted infection (STI) gonorrhea?
- a) Neisseria gonorrhoeae ✅
- b) Chlamydia trachomatis
- c) Treponema pallidum
- d) Mycoplasma genitalium
- Which of the following Gram-negative bacilli is known for causing respiratory infections in individuals with chronic lung diseases?
- a) Haemophilus influenzae
- b) Streptococcus pneumoniae
- c) Pseudomonas aeruginosa ✅
- d) Mycobacterium tuberculosis
- Which Gram-negative bacillus is responsible for causing the zoonotic disease brucellosis?
- a) Brucella melitensis ✅
- b) Yersinia enterocolitica
- c) Campylobacter jejuni
- d) Vibrio vulnificus
- Which of the following Gram-negative bacilli is known for causing wound infections and is often associated with biofilm formation?
- a) Staphylococcus aureus
- b) Pseudomonas aeruginosa ✅
- c) Streptococcus pyogenes
- d) Clostridium tetani
- Which Gram-negative bacillus is responsible for causing the foodborne illness botulism?
- a) Clostridium botulinum
- b) Bacillus cereus
- c) Staphylococcus aureus
- d) Vibrio cholerae
- Which of the following Gram-negative bacilli is known for causing the sexually transmitted infection (STI) chancroid?
- a) Haemophilus ducreyi ✅
- b) Neisseria gonorrhoeae
- c) Treponema pallidum
- d) Chlamydia trachomatis
- Which Gram-negative bacillus is responsible for causing the zoonotic disease tularemia?
- a) Francisella tularensis ✅
- b) Yersinia pestis
- c) Brucella abortus
- d) Vibrio parahaemolyticus
- Which of the following Gram-negative bacilli is known for causing the foodborne illness listeriosis?
- a) Listeria monocytogenes ✅
- b) Staphylococcus aureus
- c) Bacillus cereus
- d) Clostridium perfringens
