Bacteria I & II - Bacteria Pathogenicity and Clinical Significance

Question 1

Staphylococcus aureus

Answer 1

Basic Classification: Aerobic Gram Positive Cocci

• TSST1
• Enterotoxins
• Skin and soft tissue infections
• Necrotizing fasciitis
• Osteomyelitis
• Endocarditis
• Toxic shock syndrome
• Cystic fibrosis pneumonia
• Diarrhea

Question 2

Coagulase negative staphylococci (i.e. Staphylococcus epidermidis)

Answer 2

Basic Classification: Aerobic Gram Positive Cocci

-Biofilm production

-Nosocomial blood stream infections associated with IV catheters
-Prosthetic material infections

Question 3

Group A Streptococcus (Streptococcus pyogenes)

β-hemolytic

Answer 3

Basic Classification: Aerobic Gram Positive Cocci

-Streptolysin O &S

• Pharyngitis
• Necrotizing Fasciitis
• Rheumatic fever
• Streptococcal Toxic
Shock Syndrome(STSS)

Question 4

Group B Streptococcus (Streptococcus agalactiae)

β-hemolytic

Answer 4

Basic Classification: Aerobic Gram Positive Cocci

-Polysaccharide capsule

• Early onset neonatal disease (pneumonia, sepsis)
• Late onset neonatal disease (meningitis, sepsis)

Question 5

Streptococcus pneumoniae

α-hemolytic

Answer 5

Basic Classification: Aerobic Gram Positive Cocci

-Polysaccharide capsule

• Community acquired pneumonia
• Otitis media
• Conjunctivitis
• Meningitis

Question 6

Streptococcus mitis

α-hemolytic

Answer 6

Basic Classification: Aerobic Gram Positive Cocci

-Polysaccharide capsule

• Native valve endocarditis
• Bacteremia

Question 7

Enterococci (non-hemolytic)

Answer 7

Basic Classification: Aerobic Gram Positive Cocci

-Surface adhesins

• Urinary tract infections
• Endocarditis
• Nosocomial VRE

Question 8

Corynbacterium diphtheriae

Answer 8

Basic Classification: Aerobic Gram Positive Bacilli

-Diphtheria toxin

• Diphtheria (pharyngeal)

Question 9

Corynebacterium jeikeium

Answer 9

Basic Classification: Aerobic Gram Positive Bacilli

-Unknown

• Foreign-body infections

Question 10

Listeria monocytogenes

Answer 10

Basic Classification: Aerobic Gram Positive Bacilli

-Hemolysin

• Gastroenteritis
• Meningitis/Encephalitis
• Pregnancy: abortion,
stillbirth, preterm labor

Question 11

Peptostreptococcus spp

Answer 11

Basic Classification: Anaerobic Gram Positive Cocci

-Unknown

• Mixed anaerobic and aerobic bacterial infections including: cutaneous, respiratory, oral or female pelvic infections

Question 12

Actinomyces israelii

Answer 12

Basic Classification: Anaerobic Gram Positive Bacilli

-Unknown

• Oral/cervicofacial infections
• Pelvic infections (IUD)

Question 13

Clostridium tetani

Answer 13

Basic Classification: Anaerobic Gram Positive Bacilli

-Tetanus toxin

• Tetanus

Question 14

Clostridium perfringens

Answer 14

Basic Classification: Anaerobic Gram Positive Bacilli

-α - toxin Enterotoxins

• Gas gangrene
• Diarrhea/Bloody, acute
necrotizing GI infection

Question 15

Clostridium botulinum

Answer 15

Basic Classification: Anaerobic Gram Positive Bacilli

-Neurotoxin

• Botulism (flaccid paralysis)

Question 16

Clostridium difficile

Answer 16

Basic Classification: Anaerobic Gram Positive Bacilli

-Toxin A and Toxin B

• Diarrhea (antibiotic or hospital acquired)

Question 17

Escherichia coli

Answer 17

Basic Classification: Aerobic Gram Negative Fermenters

-Endotoxin, exotoxins, capsule, pili

• Meningitis in newborns
• Urinary tract infection
• Gastrointestinal infection

Question 18

Enterobacter spp

Answer 18

Basic Classification: Aerobic Gram Negative Fermenters

• Exotoxins
• Endotoxins
• Capsules
• Urinary tract infection
• Nosocomial infections
• Blood infections

Question 19

Salmonella spp

Answer 19

Basic Classification: Aerobic Gram Negative Fermenters

-Adhesion proteins, survival in phagocytes, dissemination to other tissues

• Gastrointestinal infection
• Bacteremia

Question 20

Proteus spp

Answer 20

Basic Classification: Aerobic Gram Negative Fermenters

• Exotoxins
• Endotoxins
• Capsules
• Adhesion proteins
• Urinary tract infection
• Nosocomial infections
• Blood infections

Question 21

Vibrio cholerae

Answer 21

Basic Classification: Aerobic Gram Negative Fermenters

-Somatic O antigens Exotoxins

• Cholera (GI infections)

Question 22

Moraxella catarrhalis

Answer 22

Basic Classification: Aerobic Gram Negative Non-fermenters

-Uncertain, cell envelope adhesion factors

• Community acquired pneumonia

Question 23

Pseudomonas aeruginosa

Answer 23

Basic Classification: Aerobic Gram Negative Non-fermenters

-Exotoxin A, endotoxins

• Otitis externa
• Pneumonia in cystic
fibrosis
• Ventilator acquired
pneumonia
• Urinary tract infection

Question 24

Haemophilus influenzae

Answer 24

Basic Classification: Fastidious Gram Negative Bacilli/Cocci/Coccobacilli

-Polysaccharide capsule, Outer membrane protein

• Meningitis
• Epiglottitis
• Conjunctivitis
• Otitis media
• Pneumonia

Question 25

Neisseria meningitidis

Answer 25

Basic Classification: Fastidious Gram Negative Bacilli/Cocci/Coccobacilli -Polysaccharide capsule, Outer membrane protein • Meningitis

Question 26

Neisseria gonorrhea

Answer 26

Basic Classification: Fastidious Gram Negative Bacilli/Cocci/Coccobacilli -Pili, Capsule, Proteases, Adherence proteins * Gonorrhea * Pharyngitis * Conjunctivitis

Question 27

Bacteroides fragilis

Answer 27

Basic Classification: Anaerobic Gram Negative - Capsules - Endotoxins - Enzymes - Abscesses throughout body - Bacteremia - Aspiration pneumonia

Question 28

Helicobacter pylori

Answer 28

Basic Classification: Spirochetes/spiral bacteria - acid resistance - establishes residence in the stomach -duodenal and gastric ulcers

Question 29

Treponema pallidum

Answer 29

Basic Classification: Spirochetes/spiral bacteria - lack of proteins on outer membrane of cell wall - antigenic variation - 1 syphilis: painless chancre - 2 syphilis: myalgia, headache, fever, rash - 3 syphilis: neurosyphilis (general paralysis, tabes dorsalis) cardiovascular syphilis (aortic lesions, heart failure) - congenital syphilis (facial and tooth abnormalities)

Question 30

Mycobacterium tuberculosis

Answer 30

Basic Classification: Acid-fast bacilli - survive and multiply in alveolar macrophages - carried to lymphatics and can start other foci of infection - primary pulmonary disease - reactivation disease - disseminated disease (kidney, bones, etc.) - world-wide issue of public health concern

Question 31

Mycobacterium avium complex

Answer 31

Basic Classification: Acid-fast bacilli -inhibition of lysosome-phagosome fusion - pulmonary disease - disseminated infection in AIDS patients - opportunistic infection in immunocompromised hosts

Question 32

Genital mycoplasma (M. hominis, M. genitalium)

Answer 32

Basic Classification: Non gram staining bacteria - resistant to beta-lactam antibiotics - non-gonococcal urethritis in males

Question 33

Mycoplasma pneumoniae

Answer 33

Basic Classification: Non gram staining bacteria - polyclonal T-cell and B-cell activators - trigger formation of cold agglutinins (clump RBCs) - atypical pneumonia - dermatologic involvement - cardiac and neurologic complications

Question 34

Chlamydia trachomatis

Answer 34

Basic Classification: Obligate intracellular bacteria - complicated intracellular lifecycle - inhibits phagosome-lysosome fusion - urethritis - epididymitis - proctitis - cervicitis - PID - conjunctivitis - infant: conjunctivitis, pneumonitis - lymphogranuloma venereum

Question 35

Chlamydophila psittaci

Answer 35

Basic Classification: Obligate intracellular bacteria - Vertebrate vector: birds - atypical pneumonia

Question 36

Rickettsia rickettsii

Answer 36

Basic Classification: Obligate intracellular bacteria - Tick vector: Dermacentor spp - cell to cell spread (hundreds of contiguous infected epithelial cells) -Rocky Mountain spotted fever (fever and rash)