Sepsis / Septic Shock Bacteria

Question 1

Buzzwords: Catalase-positive, coagulase-positive, beta-hemolytic, TSST-1, enterotoxins, superantigen, MRSA (mecA gene)
Diseases: Toxic Shock Syndrome (TSS), skin infections, pneumonia, osteomyelitis, endocarditis
Tests: Mannitol salt agar (ferments mannitol), coagulase test, beta-hemolysis on blood agar

Answer 1

Staphylococcus aureus

Question 2

Buzzwords: Beta-hemolytic, bacitracin-resistant, CAMP test positive
Diseases: Neonatal sepsis, pneumonia, meningitis, puerperal sepsis
Tests: CAMP test, Hippurate hydrolysis positive

Answer 2

Streptococcus agalactiae (Group B Strep)

Question 3

Buzzwords: Alpha-hemolytic, optochin-sensitive, bile-soluble, encapsulated, lancet-shaped diplococci
Diseases: Meningitis, pneumonia, otitis media, sepsis (especially in sickle cell patients)
Tests: Quellung reaction (capsule), optochin sensitivity, bile solubility test

Answer 3

Streptococcus pneumoniae

Question 4

Buzzwords: Catalase-negative, bile-resistant, high salt-resistant, vancomycin-resistant enterococci (VRE)
Diseases: UTIs, endocarditis, biliary tract infections, peritonitis
Tests: Bile-esculin test positive, PYR-positive

Answer 4

Enterococcus spp. (E. faecalis, E. faecium)

Question 5

Buzzwords: Spore-forming, gamma-hemolytic, D-glutamate capsule (only protein capsule), bioterrorism, widening of mediastinum (inhalational anthrax)
Diseases: Cutaneous anthrax (black eschar), inhalational anthrax (widened mediastinum), GI anthrax (sepsis, high fatality)
Tests: Gram stain (boxcar-shaped rods), medusa head colonies on blood agar

Answer 5

Bacillus anthracis

Question 6

Buzzwords: Anaerobic, spore-forming, gas gangrene, alpha toxin (lecithinase), stormy fermentation in milk
Diseases: Gas gangrene (myonecrosis), necrotizing enteritis
Tests: Nagler reaction (alpha toxin inhibition test), double-zone hemolysis on blood agar

Answer 6

Clostridium perfringens

Question 7

Buzzwords: Lactose fermenter, indole positive, K1 capsule (neonatal meningitis), LPS endotoxin (sepsis)
Diseases: UTIs, neonatal meningitis, sepsis, diarrhea (ETEC, EHEC, etc.)
Tests: MacConkey agar (pink colonies), EMB agar (metallic green), indole test positive

Answer 7

Escherichia coli

Question 8

Buzzwords: Lactose fermenter, encapsulated, mucoid colonies, currant jelly sputum, nosocomial pneumonia, UTIs
Diseases: Pneumonia, UTIs, sepsis, liver abscesses
Tests: MacConkey agar (pink colonies), urease-positive

Answer 8

Klebsiella pneumoniae

Question 9

Buzzwords: Oxidase-positive, non-lactose fermenter, blue-green pigment (pyocyanin), grape-like odor, opportunistic pathogen
Diseases: Pneumonia (CF patients), burns/wound infections, otitis externa, sepsis, UTIs
Tests: MacConkey agar (non-fermenter), oxidase-positive

Answer 9

Pseudomonas aeruginosa

Question 10

Buzzwords: Gram-negative diplococci, oxidase-positive, encapsulated, ferments maltose, Waterhouse-Friderichsen syndrome, purpura fulminans
Diseases: Meningococcemia, meningitis, sepsis (DIC, adrenal hemorrhage)
Tests: Chocolate agar, Thayer-Martin agar, latex agglutination for capsule detection

Answer 10

Neisseria meningitidis

Question 11

Buzzwords: Swarming motility, urease-positive, struvite stones, non-lactose fermenter
Diseases: UTIs, kidney stones (struvite), sepsis
Tests: Urease test positive, H2S production on TSI agar

Answer 11

Proteus mirabilis

Question 12

Buzzwords: Safety pin (bipolar staining), protein capsule, rodent fleas, bubonic plague, pneumonic plague
Diseases: Bubonic plague, pneumonic plague, septicemia
Tests: Wayson stain (bipolar staining), culture on MacConkey

Answer 12

Yersinia pestis

Question 13

Buzzwords: Very small coccobacilli, rabbit/tick exposure, bioterrorism, ulceroglandular tularemia
Diseases: Tularemia (ulceroglandular, pneumonic, septicemic)
Tests: Serology (difficult to culture)

Answer 13

Francisella tularensis

Question 14

Buzzwords: Intracellular, tick-borne, Rocky Mountain Spotted Fever (RMSF), maculopapular rash, rash starts on wrists/ankles → trunk
Diseases: RMSF (vasculitis, thrombocytopenia, multi-organ failure)
Tests: Weil-Felix test, indirect immunofluorescence

Answer 14

Rickettsia rickettsii

Question 15

Buzzwords: Opportunistic, germ tube test positive, nosocomial sepsis, ICU patients
Diseases: Candidemia, sepsis, oral thrush, vaginitis
Tests: Germ tube test, KOH prep

Answer 15

Candida albicans

Question 16

A 23-year-old woman presents with high fever, hypotension, and a diffuse erythematous rash. She also reports vomiting, diarrhea, and altered mental status. A physical exam reveals desquamation of her palms and soles. She recently had a prolonged tampon use. Blood cultures show no growth.

Answer 16

Staphylococcus aureus – Toxic Shock Syndrome & Sepsis

Question 17

67-year-old diabetic man with a foot ulcer presents with fever, hypotension, and confusion. His wound has purulent discharge, and a CT scan shows osteomyelitis. Blood cultures grow catalase-positive, coagulase-positive Gram-positive cocci.

Answer 17

Staphylococcus aureus – Toxic Shock Syndrome & Sepsis

Question 18

A 2-day-old neonate presents with lethargy, respiratory distress, and temperature instability. The mother had prolonged rupture of membranes and did not receive intrapartum prophylaxis. The infant develops meningitis and sepsis. Blood cultures grow Gram-positive cocci in chains that are beta-hemolytic and CAMP test positive.

Answer 18

Streptococcus agalactiae (Group B Strep) – Neonatal Sepsis

Question 19

A 45-year-old man with a history of sickle cell disease presents with high fever, hypotension, and altered mental status. His blood pressure is 85/50 mmHg, and labs show leukocytosis. Blood cultures grow lancet-shaped, encapsulated Gram-positive diplococci.

Answer 19

Streptococcus pneumoniae – Sepsis in Asplenic or Immunocompromised Patients

Question 20

A 72-year-old male with a history of chronic kidney disease presents with fever and hypotension. He recently underwent prolonged catheterization for a UTI. Blood cultures grow Gram-positive, bile-resistant, catalase-negative cocci.

Answer 20

Enterococcus spp. (E. faecalis, E. faecium) – Nosocomial Sepsis

Question 21

A 37-year-old postal worker presents with fever, cough, and severe dyspnea. Chest X-ray shows widening of the mediastinum. He rapidly progresses to hypotension and multi-organ failure. Blood cultures grow Gram-positive rods with a poly-D-glutamate capsule.

Answer 21

Bacillus anthracis – Inhalational Anthrax & Sepsis

Question 22

A 42-year-old farmer presents with rapidly spreading soft tissue infection, severe pain, swelling, and crepitus at the site of a deep puncture wound. His blood pressure is 78/45 mmHg, and he has signs of DIC. Blood cultures grow anaerobic, Gram-positive spore-forming rods.

Answer 22

Clostridium perfringens – Gas Gangrene & Sepsis

Question 23

A 1-week-old infant is brought to the hospital with lethargy, poor feeding, and fever. The mother had prolonged rupture of membranes. Blood cultures grow lactose-fermenting, Gram-negative rods.

Answer 23

Escherichia coli (K1) – Neonatal Sepsis & Urosepsis

Question 24

78-year-old woman with diabetes presents with fever, altered mental status, and flank pain. Urinalysis reveals pyuria and bacteriuria. Blood cultures grow lactose-fermenting, indole-positive bacteria.

Answer 24

Escherichia coli (K1) – Neonatal Sepsis & Urosepsis

Question 25

A 60-year-old alcoholic man presents with high fever, productive cough, and confusion. His sputum is thick and blood-tinged ("currant jelly sputum"). Chest X-ray shows lobar consolidation. Blood cultures grow mucoid, encapsulated, lactose-fermenting Gram-negative rods.

Answer 25

Klebsiella pneumoniae – Sepsis in Alcoholics & Nosocomial Pneumonia

Question 26

A 48-year-old man with severe burns develops fever, hypotension, and green-colored wound exudate. His wound has a grape-like odor. Blood cultures grow oxidase-positive, Gram-negative rods that produce blue-green pigment.

Answer 26

Pseudomonas aeruginosa – Sepsis in Burn Patients & Ventilator-Associated Pneumonia

Question 27

A 19-year-old college student presents with fever, petechial rash, and hypotension. His blood pressure is 75/40 mmHg, and labs show DIC and thrombocytopenia. He rapidly develops adrenal insufficiency (hyponatremia, hyperkalemia). Blood cultures grow encapsulated Gram-negative diplococci.

Answer 27

Neisseria meningitidis – Meningococcemia & Waterhouse-Friderichsen Syndrome

Question 28

An 85-year-old woman presents with confusion, fever, and flank pain. Urinalysis reveals alkaline urine and struvite crystals. Blood cultures grow swarming, urease-positive, non-lactose fermenting Gram-negative rods.

Answer 28

Proteus mirabilis – Urosepsis in Elderly Patients

Question 29

A 35-year-old man presents with fever, chills, and swollen lymph nodes. He recently traveled to an area with rodent exposure. He develops septicemia with DIC. Blood cultures grow Gram-negative rods with bipolar "safety pin" staining.

Answer 29

Yersinia pestis – Septicemic Plague

Question 30

A 50-year-old man presents with fever, lymphadenopathy, and ulcerative skin lesions after skinning a rabbit. He develops septic shock and multi-organ failure. Blood cultures grow Gram-negative coccobacilli.

Answer 30

Francisella tularensis – Sepsis & Tularemia

Question 31

A 32-year-old man presents with fever, headache, and a macular rash that started on his wrists and ankles before spreading centrally. He reports a recent tick bite. His condition rapidly deteriorates to septic shock and multi-organ failure.

Answer 31

Rickettsia rickettsii – Rocky Mountain Spotted Fever & Sepsis

Question 32

A 60-year-old ICU patient on total parenteral nutrition and broad-spectrum antibiotics presents with fever, hypotension, and altered mental status. His blood cultures are positive for yeast with pseudohyphae formation.

Answer 32

Candida albicans – Fungal Sepsis in ICU Patients