HAEMOPHILUS, BORDETELLAE, BRUCELLAE, FRANCISELLA, YERSINIA AND PASTEURELLA, NEISSERIA Flashcards
• Small, Gram-negative, pleomorphic bacteria (do not have definite shape e.g. cocci, bacilli, or coccobacilli)
• Require special media (usually containing BLOOD or its derivatives) for isolation
- FAMILY PASTEURELLACEAE
HAEMOPHILUS spp.
the major human pathogen under Haemophilus
HAEMOPHILUS INFLUENZAE
etiologic agent of chancroid (a sexually transmitted disease)
HAEMOPHILUS DUCREYI
Aggregatibacter aphrophilus
(H. aphrophilus , H. paraphrophilus)
REQUIRES
X
V
NON HEMOLYTIC
Haemophilus influenzae
REQUIRES
X
V
HEMOLYTIC
Haemophilus haemolyticus
REQUIRES X
DO NOT REQUIRE V
NON HEMOLYTIC
Haemophilus ducreyi
• Found on the mucous membranes of the URT in humans
• Important cause of meningitis in unvaccinated children, upper & lower respiratory tract infections in children and adults
HAEMOPHILUS INFLUENZAE
COCCOBACILLARY
COCCOID BACILLI
IN PAIRS OR SHORT CHAINS
EXPRESS A CAPSULE (ANTIGEN FOR TYPING)
HAEMOPHILUS INFLUENZAE
HAEMOPHILUS MEDIUM
flat, grayish,
translucent colonies
1-2 mm diameter
after 24 hours of incubation
CHOCOLATE AGAR
H.INFLUENZAE
GROW ON sheep blood agar if with
STAPHYLOCOCCI COLONIES
—SATELLITE PHENOMENON
—— RELEASE NICOTINAMIDE ADENINE DINUCLEOTIDE (NAD)
H. INFLUENZAE
MEDIA ENHANCES GROWTH
IsoVitaleX
—-contains X and V
TEST FOR THE IDENTIFICATION OF Haemophilus INFLUENZAE
SATELLITISM TEST
acts physiologically as HEMIN
(derived from blood)
FACTOR X
invasive infections
H. influenzae biotypes I and II
polyribitol ribosephosphate (PRP)
(a sugar alcohol phosphate)
Type b- capsular antigen
test with specific antiserum immunofluorescence
CAPSULE SWELLING TEST
Most H. influenzae organisms in the normal flora of
the URT are
NOT encapsulated NTHi-
Non-typeable H. influenzae
most commonly encountered
in serious infections in humans
Type b H. influenzae
NO EXOTOXIN
H.INFLUENZAE
antiphagocytic (helps them to evade
the human’s immune system) in the absence of
specific anticapsular antibodies
CAPSULE
capsule of type b H. influenzae is the major
virulence factor
PRP CAPSULE
POLYRIBITOL RIBOSE PHOSPHATE
MORE SEVERE TYPE OF H. INFLUENZAE
Type b H. influenzae
Two most common etiologic agents of bacterial OM & acute sinusitis:
• H. influenzae (mostly NTHi)
• Pneumococci
• Encapsulated organisms may reach the bloodstream, carried to the meninges, or establish in the joints
(septic arthritis)
• Fulminating obstructive laryngotracheitis with swollen,
cherry-red epiglottis in young children (prompt
tracheostomy, intubation)
• Pneumonitis, epiglottitis may follow URTI in small
children, old & debilitated people
• Bronchitis, pneumonia in adults
H. INFLUENZAE
- Immunologic detection of antigens in spinal fluid using commercial kits
- Gram stain
- Nucleic acid amplification methods. Such as the PCR.
H. INFLUENZAE IDENTIFICATION
STANDARD MEDIUMFOR H. Influenzae
IsoVitaleX
enriched chocolate agar
• Test for X factor requirement :
o Inoculum incubated with _______________ Haemophilus organisms that do not require X factor synthesize porphobilinogen, porphyrins, protoporphyrin IX and heme.
gama- aminolevulinic acid
This indicates the presence of porphyrins so if we get a red fluorescence it is not a Haemophilus influenzae.
Red fluorescence under UV light.
INFANTS may have serum antibodies transmitted from their mothers
AT WHAT AGE
INFANTS UNDER 3 MONTHS
BY AGE ____
unimmunized children have naturally acquired anti- PRP antibodies that promote complement- dependent bactericidal killing and phagocytosis.
By age 3-5 years
H.INFLUENZAE TREATMENT
- AMPICILLIN
— but 25% produce beta lactamases - CEPHALOSPORINS ( CEFOTAXIMINE IV)
- CARBAPENEMS
LATE COMPLICATIONS OF INFLUENZA MENINGITIS:
Localized subdural accumulation of fluid w/c requires
surgical drainage.
Encapsulated H. influenzae type b is transmitted
from
person – to- person spread
by contaminated respiratory droplets
3 combination vaccines that contain
Haemophilus b conjugate vaccine:
- PRP -OMP – Hep B ( Merck & Co.,Inc)
- Dtap – IPV / PRP -T ( Sanofi Pasteur ,Inc)
- MenCY / PRP-T ( GlaxoSmithKline)
IN H. INFLUENZAE
IMMUNIZATION STARTS
age of 2 months
(3 doses at 2,4,6 months)
2 doses at 2,4 months ; booster dose between 12- 18 months.:
Koch- Weeks bacillus
HAEMOPHILUS AEGYPTUS
PINK-EYE CONJUNCTIVITIS
MILD TYPE
Brazilian purpuric fever-fever,purpura, shock ,&
death
HAEMOPHILUS AEGYPTIUS
• Causes CHANCROID ( soft chancre)
o A sexually – transmitted disease
o Ragged ulcer on the genitalia,with Marked swelling
and tenderness
o (+) Painful enlarged regional lymph nodes
HAEMOPHILUS DUCREYI
Small G(-) rods occur in strands in the lesions
HAEMOPHILUS DUCREYI
Requires X-factor but not V factor
grow best from scrapings of the ulcer base on chocolate agar containing
1% IsoVitaleX
vancomycin
incubated at 10% CO2 at 33°C.
HAEMOPHILUS DUCREYI
treatment for HAEMOPHILUS DUCREYI
- 1g Azithromycin oral
- Ceftriaxone IM
- Oral Ciprofloxacin —- 3 days
- Oral Erythromycin—- 7 days
HEALING - 2 WEEKS
- whooping cough (pertussis)
- Highly communicable and
- important pathogen of human
Bordetella pertussis
- Bordetella bronchicanis causes diseases in animals - (kennel cough for dogs, snuffles for rabbits),
respiratory disease & rarely bacteremia in human
Bordetella bronchiseptica
• minute gram-negative coccobacilli resembling H. influenza
• capsule is present
• small faintly-staining G (-) rods identified by immunofluorescence staining;
• non motile
—- ATTACHED TO CILIATED CELLS
BORDETELLA PERTUSSIS
Bordet-Gengou medium
Regan Lowe
BORDETELLA PERTUSSIS
CULTURE BORDETELLA PERTUSSIS
Bordet-Gengou medium
[potato-blood-glycerol agar] with Penicillin G
0.5mg/mL
CULTURE BORDETELLA PERTUSSIS
REGAN LOWE
[charcoal-containing medium
with
horse blood,
cefalexin
amphotericin B
• Strict aerobe; Oxidase & catalase (+)
• Nitrate, citrate & urea (-)
• Forms acid but not gas from lactose and glucose
• Does not require X and V factors on subculture
BORDETELLA PERTUSSIS
B. PERTUSIS
Bordetella operons
bvgA:
bvgA: is a transcriptional activator of the
virulence genes
B. PERTUSIS
Bordetella operons
bvgS:
responds to environmental signals
mediate adhesion to ciliated epithelial cells -
essential for tracheal colonization
Filamentous hemagglutinin and fimbriae
- similar to cholera toxin
- promotes lymphocytosis, sensitization to
histamine and enhanced insulin secretion - structure that reaches the bloodstream, thus, responsible for the systemic manifestations of pertussis disease
Pertussis toxin
inhibits phagocyte function
Adenylate cyclase toxin (ACT)
regulated by the bvg system
Dermonecrotic toxin (DNT)
Hemolysin
- inhibits DNA synthesis in ciliated cells
- responsible for the damage of ciliated cells
- not regulated by bvg
Tracheal cytotoxin
ANTIGENIC STRUCTURES PATHOGENESIS, PATHOLOGY:
B. pertusis
- in the cell wall important in causing damage to the
epithelial cells of the URT
Lipooligosaccharide
SURVIVES FOR ONLY BRIEF PERIODS
NO vectors
RESPIRATORY ROUTE
blood is NOT invaded
BORDETELLAPERTUSSIS
B. PERTUSIS
liberate TOXINS and substances that irritate surface cells
coughing and marked lymphocytosis as defense
IN B. PERTUSIS
necrosis of parts of the
epithelium
PMN infiltration
peribronchial inflammation
interstitial pneumonia
obstruction of the smaller bronchioles by mucous plugs results in atelectasis and diminished oxygenation of the
blood
——convulsions in whooping cough
Seizures and convulsions with accompanying cough
(whooping) are manifestations of B. pertussis infection.
B. PERTUSIS
INCUBATION PERIOD
2 WEEKS
B. PERTUSIS
STAGES
- mild coughing and sneezing
- large number of organisms are sprayed
- in droplets
- patient is higly infectious but not very ill
- resembles common colds
“CATARRHAL” STAGE:
B. PERTUSIS
STAGES
- cough develops in explosive character
- characteristic “whoop” upon inhalation
- this often results to broken ribs in children
“PAROXYSMAL” STAGE:
B pertussis is a common cause of
—-PROLONGED COUGH (4-6 WEEKS)
—-WBC count high 16,000 – 30,000/mL, with absolute lymphocytosis (than PMN)
—-Convalescence is slow; may take months
o 50% sensitivity
o Most useful in identifying B. pertussis after culture
on solid media
DIRECT FLUORESCENT ANTIBODY (FA) TEST
Most sensitive method to diagnose pertussis
POLYMERASE CHAIN REACTION
SEROLOGY
AFTER EXPOSURE TO B. PERTUSIS
IgA
IgG
IgM
B.PERTUSIS TREATMENT
during catarrhal stage promotes
elimination of the organism
ERYTHROMYCIN
PREVENTION OF B. PERTUSIS
PERTUSSIS VACCINE
DTaP 2,4,6, 15-18 mos, booster at 4-6 y/o
Prophylactic use of erythromycin for 5 days
• Obligate parasites of animals and humans
• Located INTRACELLULARLY
• Inactive metabolically
BRUCELLAE
Causes BRUCELLOSIS (Undulant fever, Malta fever)
BRUCELLAE
Characterized by acute bacteremic phase followed by a chronic stage
BRUCELLOSIS
o Cocci to rods 1.2 um in length in young cultures, short coccobacillary forms predominating
o Gram-negative, often stain irregularly o Aerobic, nonmotile, non-spore forming
BRUCELLA MELITENSIS
Small convex smooth colonies on enriched media
o Use carbohydrates but produce neither acid nor gas o Catalase and oxidase (+)
o H2S produced by many strains (black color)
o Reduce nitrates to nitrites
Brucella melitensis
Routes of infection OF B. MELITENSIS
○ Intestinal tract (ingestion of infected milk)
○ Mucous membranes (droplets)
○ Skin (contact with infected tissues of animals)
Portal of entry OF B. MELITENSIS
lymphatic channels
regional LN
thoracic duct
bloodstream
parenchymatous organs