GRAM-POSITIVE BACTERIA:
Organism Diagnostics Virulence Factors Clinical Manifestations Treatment
Staphylococcus
Staphylococcus 1. gram stain: 1. Protective 1. Exotoxin Dependent 1. penicillinase-resistant
aureus a. gram (+), clustered a. microcapsule a. enterotoxinÆ gastroenteritis (rapid penicillins (eg. methicillin,
cocci b. Protein A: binds IgG onset and recovery) naficillan)
(nose, skin esp. 2. culture: c. Coagulase: fibrin b. TSST-1 Æ toxic shock syndrome 2. vancomycin
hospital staff a. β-hemolytic formation around (fever, GI sx w/diarrhea, rash, 3. clindamycin
and pts; vagina) b. golden w/ sheep organism hypotension, desquamation of palms and
blood d. hemolysins soles) * if methicillin resistant, treat w/
3. Metabolic: e. leukocidins c. exfoliatinÆ scalded skin syndrome IV vancomycin
a. catalase (+) f. penicillinase (children)
b. coagulase (+) 2. Tissue-Destroying 2. Direct Invasion of Organs
c. facultative anaerobe a. hyaluronidase a. pneumonia
b. staphylokinase (lysis of b. meningitis
clots) c. osteomyelitis (children)
c. lipase d. acute bacterial endocarditis
e. septic arthritis
f. skin infection
g. bacteremia/sepsis
h. UTI
Staphylococcus 1. gram stain: 1. Protective 1. Nosocomial Infection 1. vancomycin
epidermidis a. gram (+), clustered a. polysaccharide capsule a. prosthetic joints, valves
cocci (adherence to prosthetic b. sepsis from intravenous lines
(skin, mucous 2. Metabolic: devices) c. UTI
membranes) a. catalase (+) 2. skin contamination in blood cultures
b. coagulase (-) * high antibiotic resistance
c. facultative anaerobe
Staphylococcus 1. gram stain: 1. UTIs in sexually active women 1. penicillin
saprophyticus a. gram (+), clustered
cocci
2. culture:
a. γ-hemolytic
3. Metabolic:
a. catalase (+)
b. coagulase (-)
c. facultative anaerobe
,Organism Diagnostics Virulence Factors Clinical Manifestations Treatment
Streptococcus
Streptococcus 1. gram stain: 1. capsule (83 serotypes) 1. pneumonia 1. penicillin G (IM)
pneumoniae a. gram (+), diplococci 2. meningitis 2. erythromycin
2. culture: 3. sepsis 3. ceftriaxone
(oral a. does not grow in 4. otitis media (children) 4. vaccine: against the 23 most
colonization) presence of optochin common capsular Ag’s
and bile (secretes pneumolysins that bind cholesterol of host-
b. α-hemolytic cell membranes, actual effect is unknown)
3. Metabolic:
a. catalase (-)
b. facultative anaerobe
4. (+) quellung test (encapsulated
bacteria)
Streptococcus 1. gram stain: 1. M-protein (adherence factor, 1. Direct Invasion/toxin 1. Penicillin G
pyrogenes (group a. gram (+), chains antiphagocytic, antigenic) a. pharyngitis (purulent exudates on tonsils, 2. Penicillin V
A) 2. culture: 2. lipoteichoic acid (adherence factor) fever, swollen lymph nodes) 3. Erythromycin
a. inhibited by bacitracin 3. steptokinase b. sepsis 4. Penicillinase-resistant penillicin
b. β-hemolytic 4. hyaluronidase c. skin infections (skin infections b/c might be staph)
(streptolysin 5. DNAase d. scarlet fever
OÆoxygen labile, 6. Anti-C5a peptidase e. toxic shock syndrome * après RF, cont. prophylaxis for
antigenic; SÆoxygen 2. Antibody-mediated repeat infection, if heart valve
stable, non-antigenic) a. rheumatic fever (fever, myocarditis, complications, prophylaxis avant
3. Metabolic: arthritis, chorea, rash, subcutaneous certain procedures (eg. dental work)Æ
a. catalase (-) nodules) endocarditis
a. microaerophilic b. acute post-streptococcal
glomerulonephritis ** invasiveÆ clindamycin
Steptococcus 1. gram stain: 1. neonatal meningitis 1. penicillin G
agalactiae a. gram (+), chains (urine 2. neonatal pneumonia
or CSF) 3. neonatal sepsis
(vaginal 2. culture: (urine, CSF, blood)
colonization) a. β-hemolytic
3. Metabolic:
a. catalase (-)
b. facultative anaerobe
Enterococci 1. gram stain: 1. extracellular dextran helps bind to 1. subacute bacterial endocarditis 1. ampicillin (combined w/
(group D) a. gram (+), chains heart valves 2. biliary tract infections aminoglycosides in endocarditis)
2. culture: 3. UTI
(normal colon a. bile, sodium chloride (high intrinsic resistance) *resistance to penicillin G and
flora) b. α,β,γ-hemolytic emerging resistance to vancomycin
3. Metabolic:
a. catalase (-)
b. facultative anaerobe
Streptococcus 1. gram stain: 1. subacute bacterial endocarditis 1. penicillin G
viridans a. gram (+), chains 2. dental cavities
2. culture: 3. brain or liver abcesses
(normal orophry a. resistant to optochin
nx flora & GI) b. α-hemolytic (green)
3. Metabolic:
a. catalase (-)
b. facultative anaerobe
, Organism Diagnostics Virulence Factors Clinical Manifestations Treatment
Clostridium
Clostridium 1. gram stain: 1. flagella (H-Ag (+)) 1. tetanospasmin: inhibits release of GABA and 1. tetanus toxoid: vaccine w/ formalin-
tetani a. gram (+), spore-forming glycine from nerve cellsÆ sustained muscle inactivated toxin (DPT)
rods (drumstick contraction 2. antitoxin: human tetanus immune
(soil; entry via appearance) a. muscle spasm globulin (for those never immunized)
wounds) 2. metabolism: b. lockjaw (trismus) 3. clean the wound
a. anaerobe c. risus sardonica (grin) 4. penicillin or metronidazole
d. opisthotones (pronounced back arch) 5. ventilatory assistance
e. respiratory muscle paralysis
Clostridium 1. gram stain: 1. flagella (H-Ag (+)) 1. neurotoxin: inhibits release of ACh from peripheral 1. antitoxin
botulinum a. gram (+), spore-forming nn (not secreted; released upon death of organism) 2. penicillin
rods a. cranial nerve palsies 3. hyperbaric oxygen
(soil, smoked 2. metabolism: b. muscle weakness 4. ventilatory assistance and intubation
fish, canned a. anaerobe c. respiratory paralysis
food, honey)
* infants: constipation and flaccid paralysis
Clostridium 1. gram stain: 1. non-motile 1. alpha toxin: lecithinase (splits lecithin into 1. radical surgery (amputation)
perfringes a. gram (+), spore-forming phosphocholine & diglyceride) 2. penicillin & clindamycin
rods a. gaseous gangrene 3. hyperbaric oxygen
(soil, food) 2. metabolism: • cellulites/wound infection
a. anaerobe • clostridial myonecrosis: fatal if no tx
2. superantigen (spores in food)
a. food poisoning
Clostridium 1. gram stain: 1. flagella (H-Ag (+)) 1. toxin A 1. metronidazole
difficile a. gram (+), spore-forming a. diarrhea 2. oral vancomycin
rods 2. toxin B 3. terminate use of responsible
(GI, hospitals 2. metabolism: a. cytotoxic to colonic epithelial cells antibiotic
and nursing a. anaerobe
homes) 3. immunoassay for C. difficile Î pseudomembranous enterocolitis (antibiotic-
toxin associated diarrhea)
4. colonoscopy
Organism Diagnostics Virulence Factors Clinical Manifestations Treatment
Bacillus
Bacillus 1. gram stain: 1. unique protein capsule (polymer of 1. anthrax toxin (exotoxin): 3 proteins (protective Ag 1. penicillin G
anthracis b. gram (+), spore-forming γ-D-glutamic acid: antiphagocytic (PA), edema factor (EF), lethal factor (LF)) 2. erythromycin
rods 2. non-motile a. anthrax: painless black vesicles; can be fatal 3. vaccine: for high-risk individuals
(herbivores; 2. metabolism: 3. virulence depends on acquiring 2 if untreated, woolsorter’s pulmonary disease, a. composed of protective Ag
cutaneous, b. aerobe (can be plasmids; one carries gene for protein abdominal pain, vomiting and bloody b. animal vaccine composed of
inhaled, ingested facultative) capsule, other carries gene for diarrhea (infection results in permanent live strain, attenuated by loss
endospores) 3. serology exotoxin immunity if pt survives) of its protein capsule
Organism Diagnostics Virulence Factors Clinical Manifestations Treatment
Staphylococcus
Staphylococcus 1. gram stain: 1. Protective 1. Exotoxin Dependent 1. penicillinase-resistant
aureus a. gram (+), clustered a. microcapsule a. enterotoxinÆ gastroenteritis (rapid penicillins (eg. methicillin,
cocci b. Protein A: binds IgG onset and recovery) naficillan)
(nose, skin esp. 2. culture: c. Coagulase: fibrin b. TSST-1 Æ toxic shock syndrome 2. vancomycin
hospital staff a. β-hemolytic formation around (fever, GI sx w/diarrhea, rash, 3. clindamycin
and pts; vagina) b. golden w/ sheep organism hypotension, desquamation of palms and
blood d. hemolysins soles) * if methicillin resistant, treat w/
3. Metabolic: e. leukocidins c. exfoliatinÆ scalded skin syndrome IV vancomycin
a. catalase (+) f. penicillinase (children)
b. coagulase (+) 2. Tissue-Destroying 2. Direct Invasion of Organs
c. facultative anaerobe a. hyaluronidase a. pneumonia
b. staphylokinase (lysis of b. meningitis
clots) c. osteomyelitis (children)
c. lipase d. acute bacterial endocarditis
e. septic arthritis
f. skin infection
g. bacteremia/sepsis
h. UTI
Staphylococcus 1. gram stain: 1. Protective 1. Nosocomial Infection 1. vancomycin
epidermidis a. gram (+), clustered a. polysaccharide capsule a. prosthetic joints, valves
cocci (adherence to prosthetic b. sepsis from intravenous lines
(skin, mucous 2. Metabolic: devices) c. UTI
membranes) a. catalase (+) 2. skin contamination in blood cultures
b. coagulase (-) * high antibiotic resistance
c. facultative anaerobe
Staphylococcus 1. gram stain: 1. UTIs in sexually active women 1. penicillin
saprophyticus a. gram (+), clustered
cocci
2. culture:
a. γ-hemolytic
3. Metabolic:
a. catalase (+)
b. coagulase (-)
c. facultative anaerobe
,Organism Diagnostics Virulence Factors Clinical Manifestations Treatment
Streptococcus
Streptococcus 1. gram stain: 1. capsule (83 serotypes) 1. pneumonia 1. penicillin G (IM)
pneumoniae a. gram (+), diplococci 2. meningitis 2. erythromycin
2. culture: 3. sepsis 3. ceftriaxone
(oral a. does not grow in 4. otitis media (children) 4. vaccine: against the 23 most
colonization) presence of optochin common capsular Ag’s
and bile (secretes pneumolysins that bind cholesterol of host-
b. α-hemolytic cell membranes, actual effect is unknown)
3. Metabolic:
a. catalase (-)
b. facultative anaerobe
4. (+) quellung test (encapsulated
bacteria)
Streptococcus 1. gram stain: 1. M-protein (adherence factor, 1. Direct Invasion/toxin 1. Penicillin G
pyrogenes (group a. gram (+), chains antiphagocytic, antigenic) a. pharyngitis (purulent exudates on tonsils, 2. Penicillin V
A) 2. culture: 2. lipoteichoic acid (adherence factor) fever, swollen lymph nodes) 3. Erythromycin
a. inhibited by bacitracin 3. steptokinase b. sepsis 4. Penicillinase-resistant penillicin
b. β-hemolytic 4. hyaluronidase c. skin infections (skin infections b/c might be staph)
(streptolysin 5. DNAase d. scarlet fever
OÆoxygen labile, 6. Anti-C5a peptidase e. toxic shock syndrome * après RF, cont. prophylaxis for
antigenic; SÆoxygen 2. Antibody-mediated repeat infection, if heart valve
stable, non-antigenic) a. rheumatic fever (fever, myocarditis, complications, prophylaxis avant
3. Metabolic: arthritis, chorea, rash, subcutaneous certain procedures (eg. dental work)Æ
a. catalase (-) nodules) endocarditis
a. microaerophilic b. acute post-streptococcal
glomerulonephritis ** invasiveÆ clindamycin
Steptococcus 1. gram stain: 1. neonatal meningitis 1. penicillin G
agalactiae a. gram (+), chains (urine 2. neonatal pneumonia
or CSF) 3. neonatal sepsis
(vaginal 2. culture: (urine, CSF, blood)
colonization) a. β-hemolytic
3. Metabolic:
a. catalase (-)
b. facultative anaerobe
Enterococci 1. gram stain: 1. extracellular dextran helps bind to 1. subacute bacterial endocarditis 1. ampicillin (combined w/
(group D) a. gram (+), chains heart valves 2. biliary tract infections aminoglycosides in endocarditis)
2. culture: 3. UTI
(normal colon a. bile, sodium chloride (high intrinsic resistance) *resistance to penicillin G and
flora) b. α,β,γ-hemolytic emerging resistance to vancomycin
3. Metabolic:
a. catalase (-)
b. facultative anaerobe
Streptococcus 1. gram stain: 1. subacute bacterial endocarditis 1. penicillin G
viridans a. gram (+), chains 2. dental cavities
2. culture: 3. brain or liver abcesses
(normal orophry a. resistant to optochin
nx flora & GI) b. α-hemolytic (green)
3. Metabolic:
a. catalase (-)
b. facultative anaerobe
, Organism Diagnostics Virulence Factors Clinical Manifestations Treatment
Clostridium
Clostridium 1. gram stain: 1. flagella (H-Ag (+)) 1. tetanospasmin: inhibits release of GABA and 1. tetanus toxoid: vaccine w/ formalin-
tetani a. gram (+), spore-forming glycine from nerve cellsÆ sustained muscle inactivated toxin (DPT)
rods (drumstick contraction 2. antitoxin: human tetanus immune
(soil; entry via appearance) a. muscle spasm globulin (for those never immunized)
wounds) 2. metabolism: b. lockjaw (trismus) 3. clean the wound
a. anaerobe c. risus sardonica (grin) 4. penicillin or metronidazole
d. opisthotones (pronounced back arch) 5. ventilatory assistance
e. respiratory muscle paralysis
Clostridium 1. gram stain: 1. flagella (H-Ag (+)) 1. neurotoxin: inhibits release of ACh from peripheral 1. antitoxin
botulinum a. gram (+), spore-forming nn (not secreted; released upon death of organism) 2. penicillin
rods a. cranial nerve palsies 3. hyperbaric oxygen
(soil, smoked 2. metabolism: b. muscle weakness 4. ventilatory assistance and intubation
fish, canned a. anaerobe c. respiratory paralysis
food, honey)
* infants: constipation and flaccid paralysis
Clostridium 1. gram stain: 1. non-motile 1. alpha toxin: lecithinase (splits lecithin into 1. radical surgery (amputation)
perfringes a. gram (+), spore-forming phosphocholine & diglyceride) 2. penicillin & clindamycin
rods a. gaseous gangrene 3. hyperbaric oxygen
(soil, food) 2. metabolism: • cellulites/wound infection
a. anaerobe • clostridial myonecrosis: fatal if no tx
2. superantigen (spores in food)
a. food poisoning
Clostridium 1. gram stain: 1. flagella (H-Ag (+)) 1. toxin A 1. metronidazole
difficile a. gram (+), spore-forming a. diarrhea 2. oral vancomycin
rods 2. toxin B 3. terminate use of responsible
(GI, hospitals 2. metabolism: a. cytotoxic to colonic epithelial cells antibiotic
and nursing a. anaerobe
homes) 3. immunoassay for C. difficile Î pseudomembranous enterocolitis (antibiotic-
toxin associated diarrhea)
4. colonoscopy
Organism Diagnostics Virulence Factors Clinical Manifestations Treatment
Bacillus
Bacillus 1. gram stain: 1. unique protein capsule (polymer of 1. anthrax toxin (exotoxin): 3 proteins (protective Ag 1. penicillin G
anthracis b. gram (+), spore-forming γ-D-glutamic acid: antiphagocytic (PA), edema factor (EF), lethal factor (LF)) 2. erythromycin
rods 2. non-motile a. anthrax: painless black vesicles; can be fatal 3. vaccine: for high-risk individuals
(herbivores; 2. metabolism: 3. virulence depends on acquiring 2 if untreated, woolsorter’s pulmonary disease, a. composed of protective Ag
cutaneous, b. aerobe (can be plasmids; one carries gene for protein abdominal pain, vomiting and bloody b. animal vaccine composed of
inhaled, ingested facultative) capsule, other carries gene for diarrhea (infection results in permanent live strain, attenuated by loss
endospores) 3. serology exotoxin immunity if pt survives) of its protein capsule
