Chapter 11: Haemophilus, Bordetella, and LEgionella Flashcards
why are these 3 grouped togeteher
becasue of common acquisition via the human respiratory tract
haemophilus influenzae what does name mean
haemophilus means blood loving, needs hematin in blood for bacteriums cytochrome system and needs bloods NAD+ for metabolic activity
what does haemophilus influenzae attach
lungs of persons debilitated by viral influenza infection
virulence of haemophilus influenzae
polysaccharide capsule (b subtype most common with invasive disease) -meningitis, epiglottitis, septic arthritis
nonencapsulated (nontypeable) strains can colonize upper resp tract but only cause local infection
otitis media in children and resp disease in adults weakened by preexisting lung disease
pts with COPD get frequent infections with what type of H influenzae
nontypeable which makes symptoms worse
what age are children most susceptible to h influenzae
6 months and 3 years old
what is the most serous infection caused by haemophilus influenza type b
meningitis: in children from 6 months to 3 years old
inhalation to get in then goes to LNs and blood stream where it penetrates meninges
symptoms are non specific: fever, vomiting, altered mental status
-treat with antibiotics lipid A gets released and can cause neurological effects
3 bacteria respnsible for most meningitis acquired by baby coming out of the birth canal
LESB
listeria monocytogenes
E coli
Streptococcus Group B
2 bacteria responsible for meningitis later on in life after maternal Abs worn off
new hampshire
Neisseria meningitides
Haemophilius influenzae
haemophilus infulenzae type b diseases causdd
meningitis
acute epiglottitis
septic arthritis
sepsis
Haemos are influenced to go to MASS
actue epiglottitis and haem influenaze b
large red epiglottis looks like a red cherry at base of tongue
excessive saliva will drool out of child’s mouth as they will not be able to swallow
sepsis and haem influenzae b
children btwn 6 months and 3 years present with
fever, lethargy, loss of appetite, and no evidence of localized disease
-bacteria invade blood stream via upper respiratory tract
septic arthritis and haem influenzae b
most common cause of septic arthritis in infants
role of vaccine for haem influenzae b
first vaccine hase purified b capsule can only be effective to children over 18 months
current vaccines have h influenzae capsule PRP conjugated with mutant diphtheria toxin protein, neisseria meningitides outer membrane protein, or tetanus toxoid
-activates T lymphocytes and Abs against b capsule antigens
vaccination with the Hib capsule
haemophilus ducreyi is responsible for
STD: chancroid
- painful genital ulcer
- unilateral painful swollen inguinal LNs rapidly develop in 1/2 of infected persons
haemos do cry when they get chancroid
differential diagnosis with haemophilius ducreyi
syphilis: ulcer is painless, bilateral, non-suppurative
herpes: lesions start as blisters but when break they are painful, usually have systemic symptoms like myalgias and fever (unlike chancroid)
lymphogranuloma venereum (chlamydia trachomatis)
- painless matted suppurative inguinal LNs that develop slower than chancroid
- primary ulcer disappears before nodes enlarge (coexist in chancroid)
gardnerella vaginalis
- causes what
- symptoms
causes bacterial vaginitis
burning or itching of labia
buring o on urination
copious foul smelling vaginal discharge that has fishy odor
how can gardnerella vaginalis be differentiated from other causes of vaginitis
(candida or trichomonas)
- examine slide of vaginal discharge for presence of clue cells
- tiny pleomorphic bacilli within cytoplasm
bordetella pertussis causes
-what kind of bacteria is it
whooping caugh
-gram neg rod
4 virulence factors of bordetella pertussis
pertussis toxin:
extra cytoplasmic adenylate cyclase
FHA
tracheal cytotoxin
bordetella pertussis: pertussis toxin
- B subunit binds target cell, A subunit activates cell membrane bound G reg proetins which in turn activate adenylate cyclase = increased cAMP
- causes: histamine sensitization, increased insulin syn, promotion of lymphocyte production and inhibition of phagocytosis
b pertussis: extra cytoplasmic adenylate cyclase
these are swallowed by host neutrophils, lymphocytes, and monocytes
-increases cAMP inside these cells, and causes impaired chemotaxis and impaired generation of h202 and superoxide
b pertussis: FHA
pili rod involved in binding to ciliated epithelial cells of bronchi
b pertussis: tracheal cytotoxin
destorys ciliated epithelial cells = impaired clearance of bacteria, mucus
-responsible for violent cough