basic classification, major distinguishing features, genus, pathogenicity, clinical significance

Question 1

C. difficile

Answer 1

clostridium

anaerobic gram + bacilli

straight rods, spores

pathogenicity = toxin A and toxin B

clinical: diarrhea (antibiotic or nosocomial)

Question 2

Neisseria menigitidis

Answer 2

neisseria

fastidious gram -

diplococci, oxidase +

pathogenicity = polysaccharide capsule, outer membrane protein

clinical: meningitis

Question 3

C. botulinum

Answer 3

clostridium

anaerobic gram + bacilli

straight or curved rods, spores

pathogenicity = neurotoxin

clinical: botulism (flaccid paralysis)

Question 4

neisseria gonorrhea

Answer 4

neisseria

fastidious gram -

diplococci, oxidase +

pathogenicity: pili, capsule, proteases, adherence proteins
clinical: gonorrhea, conjunctivitis, pharyngitis

Question 5

E. coli

Answer 5

enterobacteriaceae

aerobic gram - fermenters

rods, oxidase -

pathogenicity = endotoxins, exotoxins, capsule, pili

clinical= meningitis in newborns, UTIs, GI infection

Question 6

Listeria monocytogenes

Answer 6

listeria

aerobic gram + bacilli

single or short chain rods, NONbranching, motile

catalase +

pathogenicity = hemolysin

clinical: gastroenteritis, meningitis/encephalitis

in pregnancy can cause abortions, stillbirth, preterm

Question 7

C. perfringens

Answer 7

clostridium

anaerobic gram + bacilli

box car shaped rods (blunt ends), spores

pathogenicity = alpha toxin, enterotoxins

clinical: gas gangrene, diarrhea (bloody = acute necrotizing GI infection)

Question 8

peptostreptococcus spp

Answer 8

peptostreptococcus

anaerobic gram + bacilli

elongated cocci, NONspore forming

pathogenicity is unknown

clinical = mixed anaerobic and aerobic bacterial infections including cutaneous, respiratory, oral, female pelvic

Question 9

C. diptheriae

Answer 9

corynebacterium

aerobic gram + bacilli

rods, NONbranching

catalase +

pathogenicity = diptheria toxin

clinical: diptheria (pharyngeal)

Question 10

Group A strep (S. pyogenes)

Answer 10

streptococcus

aerobic gram + cocci

cocci in PAIRS and CHAINS

catalase -

B hemolytic

pathogenicity = streptolysin O & S

clinical: pharyngitis, necrotizing fasciitis, rheumatic fever, streptococcal toxic shock syndrome (STSS)

Question 11

Salmonella spp

Answer 11

enterobacteriaceae

aerobic gram - fermenter

rods, oxidase -

pathogenicity = adhesion proteins, survival in phagocytes, dissemination to other tissues

clinical: GI infection, bacteremia

Question 12

Proteus spp

Answer 12

enterobacteriaceae

aerobic gram - fermenter

rods, oxidase -

pathogenicity = endotoxins, exotoxins, capsules, adhesion proteins

clinical: UTIs, nosocomial infections, blood infections

Question 13

Vibrio cholerae

Answer 13

vibrio

aerobic gram - fermenter

rods, oxidase +

pathogenicity: somatic O antigens, exotoxins
clinical: cholera (GI)

Question 14

moraxella catarrhalis

Answer 14

moraxella

aerobic gram - non-fermenter

diplococci, oxidase +

pathogenicity: uncertain; cell envelope adhesion factors
clinical: CAP

Question 15

enterococci

Answer 15

streptococci

aerobic gram + cocci

cocci in PAIRS, CHAINS

catalase -

NON-hemolytic

pathogenicity = surface adhesins

clinical: UTIs, endocarditis, nosocomial vanco-resistant enterococcus

Question 16

A. israelii

Answer 16

actinomyces

anaerobic gram + bacilli

beaded, irregular staining on gram stain

branching, filamentous bacilli

pathogenicity = unknown

clinical = oral/cervicofacial infections, pelvic infections (IUD)

Question 17

C. jeikeium

Answer 17

corynebacterium

aerobic gram + bacilli

rods, NONbranching

catalase +

pathogenicity = unknown

clinical = foreign body infections

Question 18

C. tetani

Answer 18

clostridium

anaerobic gram + bacilli

straight rods, spores

pathogenicity = tetanus toxin

clinical: tetanus

Question 19

Pseudomonas aerigunosa

Answer 19

Pseudomonas

aerobic gram - NONfermenter

slender bacilli, oxidase +, metallic sheen, grape-like color

pathogenicity = exotoxin A, endotoxins

clinical: otitis externa, pneumonia in CF, ventilator acquired pneumonia, UTIs

Question 20

S. epidermis

Answer 20

coagulase - staphylococci

aerobic gram + cocci

cocci in CLUSTERS

catalase +

pathogenicity = biofilm production

clinical= nosocomial blood stream infections associated with IV catheters, prosthetic material infections

Question 21

S. pneumoniae

Answer 21

streptococcus

aerobic gram + cocci

cocci in PAIRS/CHAINS

catalase -

alpha hemolytic

pathogenicity = polysccharide capsule

clinical = CAP, otitis media, conjunctivitis, meningitis

Question 22

Haemophilus influenzae

Answer 22

haemophilus

fastidious gram -

coccobacilli or short rods, satellite, oxidase +

pathogenicity = polysaccharide capsule, outer membrane protein

clinical = meningitis, epiglottitis, conjunctivitis, otitis media, pneumonia

Question 23

S. aureus

Answer 23

Staphylococcus

aerobic gram + cocci

cocci in CLUSTERS

catalase +

pathogenicity = toxic shock syndrome toxin (TSST1), enterotoxins

clinical: skin and soft tissue infections, necrotizing fasciitis, osteomyelitis, endocarditis, toxic shock syndrome, CF pneumonia, diarrhea

Question 24

S. mitis

Answer 24

streptococcus

aerobic gram + cocci

cocci in pairs/chains

catalase -

alpha hemolytic

pathogenicity = polysaccharide capsule

clinical = native valve endocarditis, bacteremia

Question 25

Strep. agalactiae (group B strep)

Answer 25

streptococcus aerobic gram + cocci cocci in pairs/chains catalase - Beta hemolytic pathogenicity = polysaccharide capsule clinical = early onset neonatal disease (pneumonia, sepsis), late onset neonatal disease (meningitis, sepsis)

Question 26

Bacteroides fragilis

Answer 26

bacteroides anaerobic gram - straight bacilli, pale staining pathogenicity = capsules, endotoxins, enzymes clinical = abscesses throughout body, bacteremia, aspirational pneumonia

Question 27

Enterobacter spp

Answer 27

enterobacteriaceae aerobic gram - fermenter rods, oxidase - pathogenicity = endotoxins, exotoxins, capsule clinical = UTIs, nosocomial, blood infections

Question 28

M. pneumonia

Answer 28

mycoplasma non gram staining bacteria no cell wall, need special growth media pathogenicity = polyclonal T cell and B cell activators, trigger formation of cold agglutinins (CLUMP RBCs) clinical = atypical pneumonia, dermatologic involvement, cardiac and neuro complications

Question 29

Chlamydia trachomatis

Answer 29

obligate intracellular bacteria non-cultivable, requires living cells pathogenicity = complicated intracellular lifecycle, inhibits phagosome/lysosome fusion clinical = urethritis, epididymitis, proctitis, cervicitis, PID, conjunctivitis, lymphogranuloma venereum

Question 30

genital mycoplasma (M. hominis, M. genitalium)

Answer 30

non gram staining bacteria no cell wall, need special growth medium pathogenicity = resistant to B lactam antibiotics clinical: non gonococcal urethritis in males

Question 31

chlamydia psittaci

Answer 31

obligate intracellular bacteria non-cultivable as requires livings cells pathogenicity = vertebrate vector (birds) clinical = atypical pneumonia

Question 32

Helicobacter pylori

Answer 32

spirochetes gram - pathogenicity = acid resistance, establishes residence in stomach clinical significance = duodenal and gastric ulcers

Question 33

mycobacterium avium complex (MAC)

Answer 33

acid fast bacilli non-spore forming, non-motile Ziehl-Neelsen stain needed slow growing, fastidious growth requirements pathogenicity = inhibition of lysosome-phagosome fusion clinical = pulmonary disease, disseminated infection in AIDS patients, opportunistic in immune compromised patients

Question 34

Treponema pallidum

Answer 34

spirochete CANNOT gram stain tightly wound slender coils with pointed ends pathogenicity = lack of proteins on outer membrane of cell wall, antigenic variation clinical = primary syphilis (painless chancre) ; secondary syphilis (myalgia, headache, fever, rash); tertiary syphilis (neurosyphilis i.e general paralysis), Cv syphilis and congenital syphilis (facial and tooth abnormalities)

Question 35

Rickettsia rickettsii

Answer 35

obligate intracellular bacteria small and gram - growth requires living cells zoonotic infections caused by ticks, flease, mites pathogenicity = tick vector and cell to cell spread (hundreds of contagious epithelial cells are infected) clinical = rocky mountain spotted fever (fever and rash)

Question 36

mycobacterium tuberculosis

Answer 36

acid fast bacilli non spore forming, non motile Ziehl-Neelsen stain required due to waxy outer membrane slow growing fastidious growth requirements pathogenicity = survive and multiply in alveolar macrophages, carried to lymphatics and can start other foci of infection clinical = primary pulmonary disease, reactivation disease, disseminated disease