Chapter 1.11 Haemophilus, Bordetella, And Legionella Flashcards
What are the gram-negative rods?
Haemophilus influenzae, Bordetella pertussis, and Legionella pneumophilia
*grouped together because they are acquired though the respiratory tract
What is the meaning of haemophilus influenzae?
Haemophilus- “blood loving”- this organism requires blood-containing medium for growth
Influenzae- attacks people with viral influenza infection
What type of organism is haemophilus influenzae?
Obligate human parasite transmitted via respiratory route
What are the major subtypes of haemophilus influenzae?
A, b, c, d, e, f
- type b is associated with invasive Haemophilus influenzae disease in children such as meningitis, epiglottitis, and septic arthritis
- capsule b = bad
What patients have frequent infections with nontypeable H. Influenzae?
COPD patients which then get worsening of wheezing, shortness of breath, and cough
What is the most serious infection caused by encapsulated haemophilus influenzae?
Meningitis- caused by type b
What is the clinical presentation of an infant with meningitis from haemophilus influenzae type b?
Nonspecific signs- fever, vomiting, and altered mental status
What are the 3 bacteria responsible for most meningitis acquired by the baby coming out the birth canal?
Listeria monocytogenes, E.coli, and Group B Streococus
What 2 bacteria cause meningitis later in life of an infant (6mo.-2 years)?
Neisseria meningitides and Haemophilus influenzae
How does Haemophilus influenzae cause acute epiglottitis?
H. Influenzae type b amuses rapid swelling of the epiglottis, obstructing the respiratory system and esophagus.
What is the clinical presentation of a child with acute epiglottitis from Haemophilus influenzae?
Sore throat, fever, severe upper airway wheezing (stridor), excessive saliva out of mouth, and unable to swallow
What organism is the most common cause of septic arthritis in infants?
Haemophilus influenzae type b
What is affected with septic arthritis caused by Haemophilus influenzae?
Single joint is usually affected
What is the clinical presentation septic arthritis from Haemophilus influenzae?
Infant with fever, pain, swelling, and decreased mobility of the joint
What does a gram stain show for septic arthritis from Haemophilus influenzae?
Pleomorphic gram-negative rod
What is the clinical presentation of children with sepsis from Haemophilus influenzae?
Fever, lethargy, loss of appetite, and no evidence of localized disease
What is the most important organ in fighting off infection by encapsulated bacteria?
Spleen
What disease is caused from Haemophilus ducreyi?
Sexually transmitted disease called chancroid
What is the clinical presentation of a patient with chancroid from Haemophilus ducreyi?
Painful genital ulcer, unilateral painful inguinal lymph node that could rupture and release pus
What organism causes syphilis?
Treponema pallidum
How is an ulcer from syphilis different than an ulcer from Haemophilus ducreyi?
Syphilis ulcer- painless and associated with bilateral, painless, and nonsupperlative (no pus)
Haemophilus ducreyi ulcer- painful genital ulcer
What is the organism that causes herpes?
Herpes simplex virus 1 and 2
What is the clinical appearance of herpetic lesions?
Blisters that can rupture and be painful
Usually accompanied by systemic symptoms of myalgias and fevers
What is the difference between chancroid and herpes lesion?
Chancroid does not produce systemic symptoms
Herpes- does produce systemic symptoms
What are the characteristics of lymphogranuloma venereum?
Painless matted suppurative, slow developing inguinal lymph nodes
*also called chlamydia trachomatis
What would be included in a differential diagnosis if a patient has matted lymph notes that will rupture?
Syphilis, herpes, and lymphogranuloma venereum
What Haemophilus species grow slowly and can cause endocarditis?
H. Parainfluenzae, H. Aphrophilus, H. Paraphrophilus
What group is Haemophilus species included in?
HACEK Haemophilus species Actinobacillus species Cardiobacterium species Eikenella species Kingella species
What disease does Gardnerella vaginalis cause?
Bacterial vaginitis with anaerobic vaginal bacteria
What is the clinical presentation of a woman infected with Gardnerella vaginalis?
Burning or pruritis of the labia, burning on urination, foul smelling vaginal discharge that has a fishy odor
How can Gardnerella vaginalis be differentiated from other causes of vaginitis?
The presence of clue cells on a slide of vaginal discharge
What are clue cells?
Vaginal epithelial cells that contain pleomorphic bacilli within the cytoplasm
*in Gardnerella vaginalis cells
What disease is caused by Bordetella pertussis?
Whooping cough
What are the 4 virulence factors of Bordetella pertussis?
Pertussis toxin, extra yo plasmin adenylate Cyclades, filamentous hemagglutinin, and tracheal cytotoxin
How is whooping cough transmitted?
Via respiratory secretions on the hands or in aerosolized form
What are the 3 stages of whooping cough?
- Catarrhal stage
- Paroxysmal stage
- Convalescent stage
What occurs in the catarrhal stage of whooping cough?
Low-grade fever, runny nose, sneezing, mild cough
- disease is contagious
- lasts 1-2 weeks
What occurs in the paroxysmal stage of whooping cough?
Fever subsides
Bursts of nonproductive cough (15-25/day)
May be hypoxemic, cyanotic, eyes bulge, neck veins engorge
Vomiting
*lasts a month or longer
Who is whopping cough most common in?
Infants less than 6 months
Infants and young children more than 6 months who require hospitalization
What is one of the manifestations of the pertussis toxin?
Increased number of lymphocytes but only slight increase in neutrophils
What occurs during the convalescent stage of whopping cough?
Coughing attacks are less frequent and the patient is no longer contagious
What medium is used to assess Bordetella pertussis?
Bordet-Gengou medium (potato, blood, and glycerol)
What is the vaccination used for Bordetella pertussis?
DTaP
Diphtheria-Tetanus-accellular Pertussis
What are the characteristics of Legionella pneumophila?
Aerobic gram-negative rod
Ubiquitous in natural and man made water environments
How is legionella pneumophila transmitted to humans?
Aerosolized contaminated water is inhaled, resulting in infection Ex. Air conditioners, whirlpools, shower heads that make mist in supermarkets
T/F Legionella pneumophila is a facultative intracellular parasite
T - it settles in the lower respiratory tract but survives and replicates intracellularly in macrophage
What are the 2 unique things about Legionella?
- Is a facultative intracellular parasite for free living amoebas
- Can enter low metabolic state and survive in biofilm
What diseases are associated with Legionella?
Pontiac fever and Legionnaires’ disease
What are the clinical manifestations of Pontiac fever caused by Legionella?
Headache, muscle aches, fatigue, followed by fever and chills
*strikes suddenly and resolves in a week
What are the clinical manifestations of Legionnaires’ diseases from Legionella?
High fever and severe pneumonia
What disease is commonly caused by Legionella pneumophila?
Community acquired pneumonia
What are the unique manifestations of community acquired pneumonia from legionella pneumophilia?
Fever with pulse-temperature dissociations (high fever, low HR), severe headache, confusion, myalgia, rhabdomylosis, cough, hyponatremia, hypophosphatemia, elevated liver enzymes (AST, ALT, LDH)
