SEMR: Gram (-) bacilli Flashcards
aka enterics or coliforms
Enterobacteriaceae
all enterobacteriaceae are oxidase negative except for
Plesiomonas shigelloides
all enterobacteriaceae are motile at body temperature except
klebsiella, shigella, yersinia KYS
Enterobacteriaceae
Opportunistic Members
UTI, Septicemia, CNS and diarrheal diseases
Disease syndromes
1. Uropathogenic E. coli
2. Enterotoxigenic E.coli (ETEC)
3. Enteroinvasive E. coli (EIEC)
4. Enterophatogenic E. coli (EPEC)
5. Enterohemorrhagic E. coli (EHEC)
6. Enteroadherent E. coli (EAEC)
Escherichia coli
Enterobacteriaceae
Opportunistic Members
Escherichia coli
-Most common cause of UTI in humans
-Virulence factor :
1. pili
2. cytolysins
3. aerobactin
Uropathogenic E. coli
Enterobacteriaceae
Opportunistic Members
Escherichia coli
Virulence factor:
adherence to epithelial cells
Pili
Enterobacteriaceae
Opportunistic Members
Escherichia coli
Virulence factor: inhibit immune effector cells
Cytolysins
Enterobacteriaceae
Opportunistic Members
Escherichia coli
Virulence factor: chelate iron
Aerobactin
Enterobacteriaceae
Opportunistic Members
Escherichia coli
Also known “Montezuma’s revenge” or “turista”
Enterotoxigenic E. coli (ETEC)
Enterobacteriaceae
Opportunistic Members
Escherichia coli
Disease
-Epidemic (infant) diarrhea and traveler’s diarrhea
Virulence factor
-Fimbria
-Heat-labile (LT) and heat stable (ST) enterotoxins
Enterotoxigenic E. coli (ETEC)
Enterobacteriaceae
Opportunistic Members
Escherichia coli
Virulence factor
-Invades enterocytes causing Shigella like infection
Enteroinvasive E. coli (EIEC)
Enterobacteriaceae
Opportunistic Members
Escherichia coli
Disease
-Dysentery and Bloody stools
Other Characteristics- Sereny test (+)
-Strains can be non-motile or non-lactose fermenter
Enteroinvasive E. coli (EIEC)
Enterobacteriaceae
Opportunistic Members
Escherichia coli
Virulence factor
-Bundle-forming pilus for attachment to cells
of the small bowel
Enteropathogenic E. coli (EPEC)
Enterobacteriaceae
Opportunistic Members
Escherichia coli
Disease:
-Infantile diarrhea (watery with mucus but no blood)
Enteropathogenic E. coli (EPEC)
Enterobacteriaceae
Opportunistic Members
Escherichia coli
Also known as Verotoxic E.coli (VTEC)
Enterohemorrhagic E. coli(EHEC)
Enterobacteriaceae
Opportunistic Members
Escherichia coli
Virulence factor
-Cytotoxin (Verotoxin I & II) similar to Shiga toxin
-Serotype 0157:H7 strain (STEC) (sorbitol-MAC and
MUG negative)
Enterohemorrhagic E. coli(EHEC)
Enterobacteriaceae
Opportunistic Members
Escherichia coli
Disease
-Hemorrhagic colitis and hemolytic uremic syndrome
Enterohemorrhagic E. coli(EHEC)
Enterobacteriaceae
Opportunistic Members
Escherichia coli
Enteroadherent E. coli
-Associated with UTI and diarrheal disease
Diffusely adherent E.coli (DAEC)
Enterobacteriaceae
Opportunistic Members
Escherichia coli
Enteroadherent E. coli
-Adhere to HEp2 in a aggregative “stacked-brick “
pattern
-Produces watery diarrhea
Enteroaggregative E.coli (EAEC)
Enterobacteriaceae
Opportunistic Members
Friedlander’s bacilli
Klebsiella
Enterobacteriaceae
Opportunistic Members
Disease syndromes
-Respiratory tract (pneumonia) ,wound, urinary tract,
blood (septicemia) ,and CSF (Meningitis) infections
B-C. Klebsiella
(Friedlander’s bacilli) and
Enterobacter
Enterobacteriaceae
Opportunistic Members
-May be encapsulated and appears as mucoid colonies
that tend to “string”.
-Klebsiella is Associated with plasmid-mediated ESBL’s
Klebsiella(Friedlander’s bacilli) and
Enterobacter
Important IMVC Reactions for Lactose Fermenters
Indole: +
MR: +
VP: -
Citrate:-
E. coli
Important IMVC Reactions for Lactose Fermenters
Indole: -
MR: -
VP: +
Citrate: +
K. pneumoniae subs. pneumoniae
Important IMVC Reactions for Lactose Fermenters
Indole: +
MR: +
VP: -
Citrate: +
K. pneumoniae subs. oxytoca
Important Decarboxylase Reactions for Lactose Fermenters
LDC: +
ODC: -
ADH: -
K. pneumoniae subs. pneumoniae
K. pneumoniae subs. oxytoca
Important Decarboxylase Reactions for Lactose Fermenters
LDC: +
ODC: +
ADH: -
E. aerogenes
Important Decarboxylase Reactions for Lactose Fermenters
LDC: -
ODC: +
ADH: +
E. cloacae
Enterobacteriaceae
Opportunistic Members
Virulence factor
-Nosocomial and opportunistic pathogens causing
bacteremia, septicemia, urinary tract, respiratory
tract (pneumonias) and wound infections.
-ONPG Positive
Serratia and Citrobacter
Enterobacteriaceae
Opportunistic Members
Serratiaand Citrobacter
produces a red pigment (prodigiosin)
S. marcescens
Enterobacteriaceae
Opportunistic Members
Serratiaand Citrobacter
produces Lipase, Gelatinase and
DNase.
S. marcescens
Enterobacteriaceae
Differentiation of Tribe Proteeae
Reaction
Indole: -
MR/VP: +/-
Citrate: +
Urease: +
H2S: +
ODC: +
Motility: s/+
P. mirabilis
Enterobacteriaceae
Differentiation of Tribe Proteeae
Reaction
Indole: +
MR/VP: +/-
Citrate: d
Urease: +
H2S: +
ODC: -
Motility: s/+
P. vulgaris
Enterobacteriaceae
Differentiation of Tribe Proteeae
Reaction
Indole: +
MR/VP:+/-
Citrate:+
Urease: +/-
H2S:-
ODC:-
Motility: +
Prov. stuartii
Enterobacteriaceae
Differentiation of Tribe Proteeae
Reaction
Indole:+
MR/VP:+/-
Citrate: +
Urease: +
H2S:-
ODC:-
Motility:+
Prov. retgerri
Enterobacteriaceae
Differentiation of Tribe Proteeae
Reaction
Indole:+
MR/VP: +/-
Citrate: -
Urease: +
H2S: -
ODC: +
Motility: +
M. morganii
Enterobacteriaceae
Primary Intestinal Pathogens
-has 7 subspecies (1, 2, 3a, 3b, 4, 5, 6)
-Almost all clinical isolates are of Subgroup I
Salmonella
Enterobacteriaceae
Primary Intestinal Pathogens
Citrate V
Gas +
H2S V
LDC +
ODC +
Choleraesuis
Enterobacteriaceae
Primary Intestinal Pathogens
Citrate -
Gas -
H2S -
LDC -
ODC +
Paratyphi
Enterobacteriaceae
Primary Intestinal Pathogens
Citrate -
Gas -
H2S +
LDC +
ODC -
Typhi
Enterobacteriaceae
Primary Intestinal Pathogens
Virulence Factors
-Fimbria, ability to transverse intestinal mucosa,
enterotoxin (gastroenteritis)
Salmonella enterica subsp. enterica
Enterobacteriaceae
Primary Intestinal Pathogens
Clinical Infections
i. Acute gastroenteritis or food poisoning
ii. Enteric Fever (Typhoid fever)
iii. Bacteremia
iv. Carrier state
Salmonella enterica subsp. enterica
Enterobacteriaceae
Primary Intestinal Pathogens
Clinical Infections: Salmonella enterica subsp. enterica
-Associated with S. Typhi and S. Paratyphi
-Isolated in blood at (weeks 1 to 2), in stool (weeks
2 and 3), and in urine (weeks 3 and 4)
Enteric Fever (Typhoid fever)
Enterobacteriaceae
Primary Intestinal Pathogens
Clinical Infections: Salmonella enterica subsp. enterica
Associated with S. Typhimurium, S. Paratyphi and
S. Choleraesuis
Bacteremia
Enterobacteriaceae
Primary Intestinal Pathogens
Clinical Infections: Salmonella enterica subsp. enterica
harbor organisms in the gallbladder
Carrier state
Enterobacteriaceae
Primary Intestinal Pathogens
-Appears as metallic colonies
with a black ring in Bismuth
sulfite agar.
-Diagnosed with WIDAL’S TEST in reference laboratories.
Salmonella enterica subsp.
enterica
Enterobacteriaceae
Primary Intestinal Pathogens
Motile
H2S (+) Exp. Paratyphi A
Lysine Decarboxylase (+)
Infectious Dose: 10^6
Salmonella
Enterobacteriaceae
Primary Intestinal Pathogens
Non-motile
H2S (-)
Lysine Decarboxylase (-)
Infectious Dose: 100-200
Shigella
Enterobacteriaceae
Primary Intestinal Pathogens
Mannitol –
ONPG V
ODC –
ONPG –
Serogroup A
S. dysenteriae
Enterobacteriaceae
Primary Intestinal Pathogens
Mannitol +
ONPG –
ODC –
ONPG –
Serogroup B
S. flexneri
Enterobacteriaceae
Primary Intestinal Pathogens
Mannitol +
ONPG V
ODC –
ONPG –
Serogroup C
S. boydii
Enterobacteriaceae
Primary Intestinal Pathogens
Mannitol +
ONPG V +
ODC +
ONPG +
Serogroup D
S. sonnei
Enterobacteriaceae
Primary Intestinal Pathogens
Virulence Factors
-Mediate attachment and invasion of mucosal cells.
-S. dysenteriaeproduces neurotoxin and enterotoxin
-Other species produce only enteroxin
Shigella
Enterobacteriaceae
Primary Intestinal Pathogens
Clinical Infections
-Shigellosis or bacillary dysentery
i. First Stage involves watery diarrhea
ii. Dysenteric phase - Bloody and mucoid stools
Shigella
Enterobacteriaceae
Primary Intestinal Pathogens
Disease
§Bubonic (Glandular) and Pneumonic Plaque
Yersinia pestis
Enterobacteriaceae
Primary Intestinal Pathogens
Laboratory Diagnosis
-Bipolar staining “safety pin appearance”
-Exhibit a cauliflower appearance at 48 hrs in SBA
-Exhibit a “stalactite pattern” in broth culture
-Preferential growth at 25°C to 30°C
Yersinia pestis
Enterobacteriaceae
Primary Intestinal Pathogens
Disease
-Acute enteritis (enterocolitis)
-Arthritis and Erythema nodosum
Yersinia enterocolitica
Enterobacteriaceae
Primary Intestinal Pathogens
Laboratory Diagnosis
-Bipolar staining “safety pin appearance”
-Bull’s eye colonies in CIN agar in 48 hours
-Preferential growth at 25°C to 30°C, Motile at 25°C
Yersinia enterocolitica
Enterobacteriaceae
Primary Intestinal Pathogens
Disease
Pseudotubercles
Yersinia pseudotuberculosis
Enterobacteriaceae
Primary Intestinal Pathogens
Laboratory Diagnosis
-Bipolar staining “safety pin appearance”
-Motile at 18°C to 22°C
Yersinia pseudotuberculosis
Enterobacteriaceae
Primary Intestinal Pathogens
Yersinia
TSI Yellow/Orange
Christensen Urea –
Motility at 25°C –
ODC –
Sucrose –
Y. pestis
Enterobacteriaceae
Primary Intestinal Pathogens
Yersinia
TSI Yellow/Orange
Christensen Urea +
Motility at 25°C+
ODC +
Sucrose +
Y. enterocolitica
Enterobacteriaceae
Primary Intestinal Pathogens
Yersinia
TSI Yellow/Orange
Christensen Urea+
Motility at 25°C +
ODC –
Sucrose –
Y. pseudotuberculosis
Enterobacteriaceae
Primary Intestinal Pathogens
Yersinia
Cefsulodin-Irgasan-Novobiocin
inhibits gram (+) bacteria
and most gram (-) bacilli
Cefsulodin
Enterobacteriaceae
Primary Intestinal Pathogens
Yersinia
Cefsulodin-Irgasan-Novobiocin
inhibits gram (+) cocci
Novobiocin
Enterobacteriaceae
Primary Intestinal Pathogens
Yersinia
Cefsulodin-Irgasan-Novobiocin
inhibits gram (-) bacteria
Crystal
violet
O-F Media
Change in color in both tubes.
Enterobacteriaceae, Vibrio, Aeromonas,
Plesiomonas and Chromobacterium
Fermentative
O-F Media
Change in color in tubes w/out
mineral oil (Open tube)
Acinetobacter, Stenotrophomonas,
Pseudomonas, Burkholderia
Oxidative
O-F Media
No change in color in both
tubes. Alcaligenes, Oligella
Nonsaccharolytic
Oxidase -
Dark purple (Positive)
Pseudomonas and Burkholderia
Positive
Nonfermenting Gram (-) Bacilli
-75% of nonfermenters in nosocomial bacteremias
and 5% to 15% of nosocomial infections
-Causes bacteremia, wound infection, pulmonary
disease (Cystic fibrosis patients), UTI, endocarditis,
meningitis
-Otitis media and JACUZZI/ HOT TUB syndrome
Pseudomonas aeruginosa
Pseudomonas aeruginosa
Virulence Factor
most important exotoxin; blocks protein
synthesis
Exotoxin A
Pseudomonas aeruginosa
Virulence Factor
Polysaccharide polymer in mucoid strains
Alginate
Nonfermenting Gram (-) Bacilli
Identifying Characteristics
1. Strict aerobic
2. Pigmented
3. FRUITY, GRAPELIKE or
“CORN TORTILLA LIKE” Odor
(2-aminoacetophenone)
4. Growth at 42°C
5. Grows in Cetrimide Agar
6. Acetamide Positive
Pseudomonas aeruginosa
Pseudomonas aeruginosa
Pigments
green- P.fluorescens/P. putida
Fluorescein (Pyoverdin)
Pseudomonas aeruginosa
Pigments
blue
Pyocyanin
Pseudomonas aeruginosa
Pigments
red
Pyorubin
Pseudomonas aeruginosa
Pigments
brown/black (P. stutzeri)
Pyomelanin
Nonfermenting Gram (-) Bacilli
Clinical significance
1. Associated with ventilators, humidifiers, catheters, etc.
2. Opportunistic (1-3% of all nosocomial infection, 2ndmost commonly
isolated non-fermenter); burns, trauma
3. About 25% of adults present in skin; 7% in pharynx
4. Ubiquitous; found in soil, water, foodstuffs
Acinetobacter spp
Nonfermenting Gram (-) Bacilli
Acinetobacter spp
Saccharolytic (glucose oxidizing), nonhemolytic strains.
A. baumannii
Nonfermenting Gram (-) Bacilli
Acinetobacter spp
Asaccharolytic, nonhemolytic strains.
A. lwoffii
Nonfermenting Gram (-) Bacilli
Acinetobacter spp
β-hemolytic strains.
A. haemolyticus
Nonfermenting Gram (-) Bacilli
Identifying Characteristics
1. Plump, paired gram negative coccobacilli
Acinetobacter spp.
Nonfermenting Gram (-) Bacilli
Acinetobacter spp.
may exhibit
PURPLISH hue (due to lactose
oxidation)
A. baumannii
Nonfermenting Gram (-) Bacilli
Acinetobacter spp.
appears with a BLUE-GREY
(cornflower blue) center
in EMB.
A. baumannii
Nonfermenting Gram (-) Bacilli
Clinical significance
1. Contaminants in blood drawing equipment (collection tubes, disinfectants,
transducers, venous catheters, etc.)
2. Opportunistic (3rdmost commonly isolated among nonfermenters)
3. Intrinsic resistance commonly used antibacterial agent
(aminoglycosides and beta lactams)
Stenotrophomonas maltophilia
Nonfermenting Gram (-) Bacilli
Clinical significance
“Melioidosis”
-Bipolar staining (safety pin) in Gram Stain
Burkholderia pseudomallei
Nonfermenting Gram (-) Bacilli
Burkholderia pseudomallei
(pulmonar disease) formation of abscess
Melioidosis
Nonfermenting Gram (-) Bacilli
Identifying characteristics
1. Bipolar staining (safety pin) in Gram Stain
2. Smooth to wrinkled colonies in BAP
3. Wrinkled and deep pink in Ashdown media
4. “Earthy odor”
5. “Sniffing” of plate is discouraged (work on BSC)
Burkholderia pseudomallei
Nonfermenting Gram (-) Bacilli
“Associated with patients with CF (cystic fibrosis) and CGD (chronic
granulomatous disease)
Burkholderia gladioli
Nonfermenting Gram (-) Bacilli
-Glanders- zoonosis affecting horses,mules,donkeys. Formation of
nodular lesions in lungs. Coughing, fever and release of infectious nasal
discharge.
-Potential bioterrorist agent
-Nonmotile; non-pigmented colonies; no distinct odor
Burkholderia mallei
Nonfermenting Gram (-) Bacilli
Biochemical Physiologic Characteristics
Oxidase: -
Pigment: Y
Glucose: +
Maltose: S/+
Growth at 42°: +/-
S. maltophilia
Nonfermenting Gram (-) Bacilli
Biochemical Physiologic Characteristics
Oxidase: -
Pigment: -
Glucose: -
Maltose: -
Growth at 42°: -
A. lwoffii
Nonfermenting Gram (-) Bacilli
Biochemical Physiologic Characteristics
Oxidase: -
Pigment: -
Glucose: +
Maltose: +/-
Growth at 42°: +
A. baumannii
Nonfermenting Gram (-) Bacilli
Biochemical Physiologic Characteristics
Oxidase:
Pyoverdin:
Pyocyanin Acetamide 42° Growth:
Gelatin hydrolysis:
LDC-ONPG:
Nonfermenting Gram (-) Bacilli
Biochemical Physiologic Characteristics
Oxidase: +
Pyoverdin: +
Pyocyanin Acetamide 42° Growth: -
Gelatin hydrolysis: +
LDC-ONPG: -
P. fluorescens
Nonfermenting Gram (-) Bacilli
Biochemical Physiologic Characteristics
Oxidase: +
Pyoverdin: +
Pyocyanin Acetamide 42° Growth: -
Gelatin hydrolysis: -
LDC-ONPG: -
P. putida
Nonfermenting Gram (-) Bacilli
Biochemical Physiologic Characteristics
Oxidase: +
Pyoverdin: -
Pyocyanin Acetamide 42° Growth:
Gelatin hydrolysis:
LDC-ONPG: +/-
B. cepacia
Nonfermenting Gram (-) Bacilli
Biochemical Physiologic Characteristics
Oxidase: +
Pyoverdin: -
Pyocyanin Acetamide 42° Growth:
Gelatin hydrolysis:
LDC-ONPG: -
B. pseudomallei
General Characteristics
i. Dysgonic (slower or poorer
growing)
ii. Associated to SUBACUTE BACTERIAL ENDOCARDITIS
iii. Normal biota of the oral cavity
iv. Fail to grow in MacConkey
v. Glucose fermenter
(Require serum to the
fermentative media)
vi. Opportunistic bacteria
Fastidious Gram Negative Bacilli
Fastidious Gram Negative Bacilli
HACEK Group
1. Aggregatibacter (formerly Haemophilus) aphrophilus
2.Aggregatibacter (formerly Actinobacillus)
actinomycetemcomitans
3.Cardiobacterium hominis
4.Eikenella corrodens
5.Kingella spp.
Fastidious Gram Negative Bacilli
HACEK Group
-“foam loving” or needing high conc.of CO2
- Found in dental and gingival scrapings
Aggregatibacter aphrophilus
Fastidious Gram Negative Bacilli
HACEK Group
Virulence Factor
-Collagenase and Leukotoxin
Disease
-Destructive periodontitis
-Subacute bacterial endocarditis
Aggregatibacter actinomycetemcomitans
Fastidious Gram Negative Bacilli
HACEK Group
Microscopic characteristics
-Short bacilli in pairs /chains
-Bipolar staining “Morse Code”
appearance.
Aggregatibacter actinomycetemcomitans
Fastidious Gram Negative Bacilli
HACEK Group
Colonial appearance
-Pinpoint (24 hr ). With
star shape with 4 to 6 point”
in the center of the colony (48 hrs).
Aggregatibacter actinomycetemcomitans
Fastidious Gram Negative Bacilli
HACEK Group
Disease
-Oral Infections
-Subacute bacterial endocarditis
Characteristics
-Fermenter (dysgonic); pits agar
-Pleomorphic gram (-) rod that
tend to form rosettes or long
filaments
Cardiobacterium hominis
Fastidious Gram Negative Bacilli
HACEK Group
Disease
-Infections from human bites or fights
(clenched fist wounds)
-Cellulitis-needle use by drug addicts
-Oral Infections and Subacute bacterial endocarditis
Eikenella corrodens
Fastidious Gram Negative Bacilli
HACEK Group
Characteristics
-Non Fermenter; Pit agar; Chlorine bleachlike odor
-Non-motile, oxidase positive, asaccharolytic,
catalase negative; yellow pigment
Eikenella corrodens
Fastidious Gram Negative Bacilli
HACEK Group
Disease-major gram(-) bacteria in
bone infections in chidren below 3y.o
-Oral, blood, bone Infections
-Subacute bacterial endocarditis
Kingella spp.
Fastidious Gram Negative Bacilli
HACEK Group
Kingella spp.
Characteristics
-Short bacilli to coccobacilli
with squared ends in pairs/in chains
-Fermenter (dysgonic); pits agar
-Nonhemolytic (–) or
β-hemolytic (K.kingae)
K. denitrificans
Fastidious Gram Negative Bacilli
HACEK Group
Kingella spp.
Characteristics
-Short bacilli to coccobacilli
with squared ends in pairs/in chains
-Fermenter (dysgonic); pits agar
-Nonhemolytic (K. denitrificans) or
β-hemolytic (–)
K.kingae
Fastidious Gram Negative Bacilli
Infections
Periodontitis; Local infection to fulminant infection (septicemia) esp. in neutropenic patients
Capnocytophaga
Fastidious Gram Negative Bacilli
i. Microscopy
-Thin and fusiform, spindle-shaped, coccoid and curved filaments
ii. Culture Characteristics
-Haze (gliding motility) on solid surface
-opaque, shiny; pale beige or yellowish
-Resemble HACEK in CO2 requirement
§May produce yellow pigment; can resemble colonies of E.corrodens
Capnocytophaga
Fastidious Gram Negative Bacilli
Infections
-Systemic, pneumonic and cutaneous infection
from animal (often cats) bites (zoonosis)
Laboratory Diagnosis
i. Microscopy
-Coccobacilli (ovoid, filamentous or bacilli);
Bipolar staining
ii. Culture Characteristics
-Grayish, non hemolytic, mucoid with narrow green
to brown halo around the colony
Pasteurella multocida
Fastidious Gram Negative Bacilli
Infections
-Brucellosis (Undulant/Malta fever)- zoonosis-acquired through aerosol, percutaneous and oral routes; Category B biological agents ( high morbidity, low mortality)
Symptoms: fever,malaise,headache,anorexia,myalgia
Laboratory Diagnosis
Microscopy
-Coccobacili or bacilli
Culture and Other Characteristics
-Smooth, raised and translucent colonies
-Facultative intracellular pathogens
-Biosafety Practice Level 3
Brucella
Fastidious Gram Negative Bacilli
Brucella
Natural Host:Goat or
sheep
Serum Agglutination: +
H2S (Lead
Acetate): -
Urease: V
Thionine: -
Fuchsin:-
B.melitensis
Fastidious Gram Negative Bacilli
Brucella
Natural Host:Cattle
Serum Agglutination:+
H2S (Lead
Acetate):+
Urease: +<2 hrs.
Thionine: +
Fuchsin:-
B. abortus
Fastidious Gram Negative Bacilli
Brucella
Natural Host:Swine
Serum Agglutination:+
H2S (Lead
Acetate):+
Urease: +<0.5 hrs.
Thionine: -
Fuchsin: +
B.suis
Fastidious Gram Negative Bacilli
Brucella
Natural Host:Dogs
Serum Agglutination:-
H2S (Lead
Acetate):-
Urease: +<0.5 hrs.
Thionine: -
Fuchsin:-
B. canis
Fastidious Gram Negative
Bacilli
Infections- zoonosis (ingestion, inhalation, arthropod bite), highly infectious
-Tularemia (ulceroglandular, pneumonic, etc)-rabbit fever, water rat trappers disease
Laboratory Diagnosis
Microscopy
-Small, non-motile, coccobacili or bacilli
Culture and Other Characteristics
-Strictly aerobic; require cysteine, cystine or thiosulfate (SBA, BCYE agar, CHOC)
-Gray-white, smooth, raised colonies
-Biosafety Practice Level 3
Francisella tularensis
Fastidious Gram Negative Bacilli
Clinical Significance
i. Virulence Factor
a. Enter, survive and multiply within macrophages
b. Survive and multiply within free-living protozoa
c. Multiply at 20°C to 43°C and survive at 40°C to 60°C
d. Capacity to adhere and persist in piped water systems
Infections- Atypical pneumonia
a. Legionnaire’s disease- fever w/ pneumonia
(sporadic,epidemic,nosocomial)
a. Pontiac Fever- fever w/o pneumonia
Legionella pneumophila
Fastidious Gram Negative Bacilli
Epidemiology
-Aquatic sources (lakes, rivers, hot springs and mud)
-Man made distribution systems
-Humidifiers and respiratory therapy equipment
Specimen Collection and Handling
-Respiratory secretion, body fluids,
abscess, blood. Urine for Ag detection
Microscopic Examination
-Pleomorphic and weakly staining
gram (-) bacilli
-Direct immunofluorescent antibody
test, Silver or Giemsa stains
Legionella pneumophila
Fastidious Gram Negative Bacilli
Colony Morphology
-Grayish-white or blue green, convex, and glistening
measuring 2-4 mm in diameter
-Characteristic “ground-glass” colony
Legionella pneumophila
Fastidious Gram Negative Bacilli
Bordetella
Virulence Factors
facilitate attachment to ciliated
epithelial cells.
FHA and Pertactin
Fastidious Gram Negative Bacilli
Bordetella
Virulence Factors
interferes to signal transduction.
Pertussis toxin
Fastidious Gram Negative Bacilli
Bordetella
Virulence Factors
inhibits host epithelial and
immune effector cells.
Adenylate cyclase toxin
Fastidious Gram Negative Bacilli
Bordetella
Virulence Factors
causes ciliostasis and DNA
synthesis
Tracheal cytotoxin
Fastidious Gram Negative Bacilli
Clinical Manifestations
-Pertussis (whooping cough)
-Catarrhal, Paroxysmal, Convalescent phase
Epidemiology
-Droplets or direct contact with secretions
-Organism adhere and replicate on ciliated respiratory
epithelial cells
Bordetella
Bordetella pertussis and B. parapertussis
Fastidious Gram Negative Bacilli
Microscopic and Colony morphology
-Tiny gram-negative
coccobacilli
-Smooth, glistening
and silver, resembling
mercury droplets
Bordetella
Bordetella pertussis and B. parapertussis
Fastidious Gram Negative Bacilli
Bordetella
Laboratory Diagnosis
Charcoal-horse blood + (3-5 d)
Blood agar -
Mac/Catalase/Motility -
Oxidase +
Urease -
B. pertussis
Fastidious Gram Negative Bacilli
Bordetella
Laboratory Diagnosis
Charcoal-horse blood + (2-3 d)
Blood agar +
Mac/Catalase/Motility -
Oxidase -
Urease + 24 hours
B. parapertussis
Fastidious Gram Negative Bacilli
Bordetella
Laboratory Diagnosis
Charcoal-horse blood + (1-2 d)
Blood agar +
Mac/Catalase/Motility +
Oxidase +
Urease + 4 hours
B. bronchiseptica
