Gram
Gram NEG What’s +/- Diseases/Key words Virulence
Stain
Escherichia coli GN bacilli Cat + Most common UTI Endotoxin
Lact + Most common GN bacteremia Heat labile
All ferment glucose, are catalase negative, and oxidase negative.
Oxid – Most common neonatal meningitis (with group B strep) Heat stable
Facultative Anaerobes – capacity to switch to anaerobic.
Purple on Diarrhea Pili (adhesion)
MacConkeys
ETEC SI, watery D, cramps, nausea, and low grade fever. Enterotoxins promote water and electrolyte losses. Traveler’s/Mont Revenge
EIEC LI, fever, cramping, watery diarrhea followed by development of dysentery with scant, bloody stools. Invasion and destruction of
epithelial cells linging the colon.
EHEC LI, severe abd cramping, intial watery diarrhea followed by grossly bloody diarrhea, little or no fever
Klebsiella GN Cat – Pneumonia (compromised pulmonary function and Thick Capsule
Enterics Family
pneumonia Lact + alcoholics) Non-motile
Oxid - UTI, bacteremia
Current jelly (blood) sputum
Serratia GN Cat – Opportunistic infection
marcescnes Oxid - Bright red pigment
Shigella flexneri GN bacilli Lact – Dysentery (invasive diarrhea): watery, bloody diarrhea Shiga toxin
Oxid – Painful bloody diarrhea Non-motile
Anaerobic
Proteus mirabilis GN Urease + Hospital acquired infections Motile
UTI!!
Salmonella GN bacilli Lact – Eating undercooked chicken and eggs non-bloody Motile
Oxid – diarrhea
Produces Enteric *typhoid* fever, gastroenteritis, bactermia
H2S
Vibrio cholera GNR Oxid + Raw oysters – watery diarrhea with mucus AB toxin
Vibrionaceae Family
“Comma” Rice water stool/Cholera Flagellum
Vibrio GN Explosive, crampy diarrhea assoc with shellfish (raw
parahaemolyticus oysters and sushi)
Campylobacter GN bacilli Oxid + Most common cause of diarrhea! Bloody D assoc with Motile
jejuni Grows best undercooked meat Adhesion
in low O2 Gastroenteritis – poultry or milk that is contaminated Endotoxin
H.pylori GN bacilli Urease + Ulcers Motile/Flagella
Pseudomonas GN bacilli Cat + Pneumonia Capsule
Pseudomonas Family
aeruginosa Lact – Otitis media Endo and Exotoxin
Oxid + Opportunistic disease esp. for burn pts! Flagella
Aerobe Endocarditis, sepsis
Glucose Fruity smell
non-
fermenting
Blue-green
pigment
Bacteroides GN Anaerobic MOST COMMON SPECIES IN COLON! Capsule
fragilis cocbacillus Foul smelling, abscess Pili, endotoxin
Intra-abd abscess, pelvic infections, wound infections and Normal GI flora
Bacteroidaceae
bacteremia
Bacteroides GN Periodontal disease and aspiration pneumonia
melaninogenicus
Family
Fusobacterium GN Periodontal disease and aspiration pneumonia and AOM,
abscess
Haemophilus GNR Chocolate Meningitis! Capsule
influenzae agar Septic arthritis/Sepsis Attachment pili
Pneumonia X and V factors
OT, sinusitis, COPD exacerbation
Gram Negative Rods
Epiglottitis!
Haemophilus GNR STD! _ chancroid (painful ulcer)
dureyi
Bordetella GNR Whooping cough Endotoxin
pertussis Adhesions
Atypical pneumonia
Legionell GNR Aerobic Capsule
Legionnaire’s disease-pneumonia, fever and unproductive
pneumophila Cat +
cough
Brucella GNR Unpasteurized milk/cheese – fever, loss of appetite and
weakness
Shigella, Salmonella, Virbio are NEVER considered normal flora. – Always pathogenic.
Salmonella, Shigella, Campylobacter, ETEC, and Norwalk/Rotavirus – assoc with diarrhea. Diarrhea: increased in stool frequency, wt and liquidity of stools. Most
common cause is infectious. Acute diarrhea assoc. with viruses (70%).
Dysentery: intestinal inflammation with severe diarrhea, mucous and bloody stools and systemic disturbances.
Differential diagnosis and treatment of common types of acute diarrhea
Agent Epidemiology, Signs and Diagnostic
Transmission And Symptoms Evaluation
Related Factors
Salmonella Contaminated poultry, raw milk, foreign Nausea, vomiting, diarrhea, fever, Stool examination for
travel abdominal cramps, tenesmus, PMN and culture-Invasive
incubation period of 6-48 hr
Shigella Contaminated H2O, mixed salads, foreign Diarrhea, fever, PMN leukocytes in stools-Invasive
travel, day care centers tenesmus, bloody stools (incubation
period of 12-72 hr)
Campylobacter Raw milk, contaminated H2O,day care Incubation period of 2-7 days PMN leukocytes in stools
Jejuni centers, foreign travel culture
Clostridium Antibiotics, immunosuppression Diarrhea (mild to C. difficile toxin, C. difficile is rarely
Difficile severe), abdominal identified in the culture ; can do
cramps Colonoscopy and biopsy
Staphylococcus Contaminated meats, salads, cream-filled Incubation period of 1-8 hr) resolves History and stool cultures
Aureus pastries in 24-48 hr
Enterotoxigenic Contaminated food/H2O ingestion, Nausea, vomiting, diarrhea (mild to Stool culture
Escherichia coli foreign travel severe, with 24-48hr onset time)
Cryptosporidiosis Immunosuppression, contaminated H2O, Diarrhea (mild to severe; chronic or Special stool culture methods
animal handlers, day care centers self-limited) with large fluid losses
Viral Community outbreaks, contaminated Nausea, diarrhea (self-limited) Viral studies
gastroenteritis food
Gram
Gram NEG What’s +/- Diseases/Key words Virulence
Stain
Neisseria GNC Oxid + Meningitis: petechial rash, sudden fever, purpura (black Endotoxin - LOS
Only Pathological
meningitides Diplococci and blue marks) on skin, malaise and stiff neck. Capsule
CSF sample taken. Waterhouse-Friderichesen syndrome. Pili
GN cocci
High risk groups = infants and army recruits.
Neisseria GNC Glucose+ Gonorrhea: greenish-yellow d/c from penis. Pili, invades mucosal cells
gonorrhoeae Diplococci Oxidase – PID – most common cause (with chlamydia) IgA protease
Catalase + Thayer martin medium. VCN culture to diagnosis.
Pharyngitis, Urethritis, disseminated jt disease, arthritis
Moraxella GN Otitis media and URI in COPD/emphysema pts
catarrhalis
GN
Kingella kingae GN Septic arthritis and osteomyleitis in children
ENDOCARDITIS – haemophilus, actinobacillus,
cardiobacterium, eikenlla and kingella
Chlamydia GN Obligate Urethritis, conjunctivitis, mucocutaneous lesions Reticulate bodies and Elementary bodies
trachomatis Lacks cell intracellular Infertility. Blindness. EB infects cells becomes RB
Intracellular
wall parasite In-turned eyelashes
Parasites
Obligate
UTI/STD/PID
Rickettsia GN Obligate Damages endothelial cells lining blood vessels Non-motile
intracellular Rickettsii – Rocky mt spotted fever [tick]
parasite Akari – pox (vesicular rash) [mites]
Prowazeki – louse typhus [louse]
Mycoplasma and No cell Required Walking pneumonia (mycoplasma) – nagging, non-
Mycoplasma
Ureaplasma wall chol productive cough, low grade fever, HA and fatique
Atypical pneumonia
Urethritis (ureaplasma)
Treponema GN Anaerobe Syphilis – painless ulcer (chancre) Hyaluronidase promotes invasion,
Spirochete
pallidum Spirochete VDRL testing adherence and immunopathogenesis
Borrelia GN Tick bite – deer Lyme disease – high fever, chills, muscle Motile
burgdorferi Spirochete ache, HA, bacteremia Endotoxin
Gram
ACID FAST What’s +/- Diseases/Key words Virulence
Stain
VIRUS What’s +/- Diseases/Key words Virulence