Fastidious Flashcards
Genera that belong to the family Pasteurellaceae
Haemophilus
Actinibacillus
Pasteurella
Aggregatibacter
Known to cause zoonotic infections
Pasteurella
Brucella
Francisella
Indigenous human flora and have been implicated in cases or bacterial endocarditis
Haemophilus
Aggregatibacter
Cardiobacterium
Eikenella
Kingella
Characteristics of Haemophilus
Non-motile
Facultative anaerobic
Oxidase positive
Catalase positive
Nitrate reductase positive
Haemophilus is derived from the Greek word meaning _____
Blood-lover
Haemophilus sp. obtains X factor from _____ and V factor from _____
Blood Agar Plate (BAP)
V factor-producing organisms
Other organisms that produces B factor as products of metabolism
Staphylococcus aureus
Streptococcus pneumoniae
Neisseria spp.
All clinically important Haemophilus species may demonstrate satellitism except for
Haemophilus ducreyi
Erroneously implicated in the influenza pandemic of 1889-1890
H. influenza
Has an anti-phagocytic and anti-complementary property
Capsule
Virulence factos of H.influenzae
Capsule
Immunoglobulin A (IgA) proteases
Adherence mechanism
Outer membrane proteins and lipopolysaccharide
The serologic grouping of H. influenzae into six antigenically distinct types which are the:
A, B, C, D, E, and F
Implicated in invasive infections such as meningitis in children.
Serotype B
An enzyme capable of breaking down secretory IgA that protects the mucosal surfaces
Immunoglobulin A (IgA) proteases
Lacks adherent properties which explains its tendency to cause systemic infections
Serotype B
Two patterns of disease under H. influenzae
- Invasive and systemic disease by encapsulated strains
- Localized infection by non-typable H. influenzae or NTHi (unencapsulated strains)
Examples of invasive disease:
Septicemia
Meningitis
Arthritis
Epiglottitis
Tracheitis
Pneumonia
Examples of localized infection:
Conjunctivitis
Sinusitis
Otitis media with effusion (middle ear infections)
Haemophilus influenzae serotype b (Hib) in children
Meningitis
Rapid onset, acute inflammation, intense edema of the epiglottis
Epiglottitis
May cause complete airway obstruction
Epiglottitis
Epiglottitis occurs in children between what ages?
2 to 4 years old
Life threatening disease in children; Can arise after an acute, viral respiratory infection
Bacterial tracheitis
Observed in conjunctivitis exudates from Egyptians by Koch in 1883
H. aegypticus (Koch-Weeks Bacillus)
H. aegypticus is associated with _____
Pinkeye conjunctivitis
H. aegypticus is observed in conjunctivitis exudates from Egyptians by _____ in _____
Koch
1883
Agent of chancroid (soft chancre), a type of genital ulcer disease
H. ducreyi
Infects mucosal epithelium, genital and nongenital skin, and regional lymph nodes
H. ducreyi
H. ducreyi incubation period
4 to 14 days
Endocarditis of insidious onset. In which no signs and symptoms are seen before becoming apparent
H. parainfluenzae
Pharyngitis
H. parahaemolyticus
Specimens for Haemophilus spp.
Blood, CSF, middle ear exudate, joint fluids, respiratory tract specimen, swabs from conjunctiva, vaginal swabs, and abscess drainage
For the isolation of H. ducreyi, the site should be cleaned with _____ moistened with _____
Sterile gauze
Sterile saline
A swab pre moistened with _____ saline is used to collect material from the ulcer
Sterile phosphate buffered saline
H. influenza grow on _____
Chocolate Agar Plate (CAP)
For respiratory specimens, CAP supplemented with _____ can be used
Bacitracin
Milligrams required for bacitracin to be supplemented with CAP
300 mg/L
For H. aegypticus and H. ducreyi, CAP is supplemented with _____
1% Iso-VitaleX or Vitox
For _____ and _____, CAP is supplemented with 1% Iso-VitaleX or Vitox
H. aegypticus
H. ducreyi
Chemical supplements intended to nourish fastidious organisms
Vitox
Chocolate agar plate is a commonly used medium incubated between _____ and _____ in an atmosphere of 5% to 10% carbon dioxide (CO2)
33 degree Celsius and 37 degree Celsius
Chocolate agar plate is a commonly used medium incubated between 33°C and 37°C in an atmosphere of _____ to _____ carbon dioxide (CO2)
5% to 10%
In contrast to other species Haemophilus ducreyi grows best at _____
33 degree Celsius
In contrast to other species _____ grows best at 33°C
Haemophilus ducreyi
Colonies of H. influenzae on CAP appear:
Translucent, tannish, moist, smooth and convex, with distinct odor
H. ducreyi appears as:
Small, flat, smooth, nonmucoid, transparent to opaque colonies or appears tan or yellow
Capsules of _____ may be observed in gram-stained smears, as clear, non-staining halo surrounding the bacteria
H. influenzae
Appear as pale staining gram-negative coccobacilli arranged singly or in groups
H. ducreyi
Used to differentiate heme-producing species of Haemophilus
Porphyrin Test
Principle of Porphyrin Test
Tests the ability of the organism to convert d-aminolevulinic acid (d-ALA) into porphyrins or porphobilinogens
Detection of porphobilinogen is detected by addition of _____
Kovacs’ reagent
Porphyrins can be detected using an _____ with a wavelength of about 360 nm
Ultraviolet light
Porphyrins can be detected using an ultraviolet light with a wavelength of about _____
360nm
Risk factors for infective (bacterial) endocarditis include:
Tooth extraction, history of endocarditis, gingival surgery, heart valve surgery, and mitral valve prolapse
Found in dental plaque and gingival scrapings
Aggregatibacter aphrophilus
Describe the colonies of Aggregatibacter aphrophilus:
Convex, granular, and yellow with an opaque zone near the center on CAP
The most frequently isolated member of the HACEK group that is seen in cases of endocarditis.
Aggregatibacter aphrophilus
Infected patients of Aggregatibacter aphrophilus typically present with;
Fever, congestive heart failure, and embolism
Small bacilli to coccoid gram-negative bacilli that are nonmotile
Aggregatibacter actinomycetemcomitans
Aggregatibacter actinomycetemcomitans is isolated from:
Blood, lung tissue, abscesses of the mouth and brain
Implicated in endocarditis and periodontitis
Aggregatibacter actinomycetemcomitans
An infection of the gums that may exacerbate into destruction of the bones that support the teeth
Periodontitis
Pleomorphic, nonmotile, fastidious, gram-negative bacillus
Cardiobacterium hominis
Form rosettes or flower like symmetries or patterns agar depression, swellings, long filaments, or sticklike structure in yeast extract
Cardiobacterium hominis
Normal flora, of the nose mouth and throat and has been implicated in endocarditis following oral infections or dental procedures
Cardiobacterium hominis
Normal flora of the oral cavity and infections, typically occur after trauma such as human bites
Eikenella corrodens
Implicated in periodontitis, meningitis, empyema, pneumonia, osteomyelitis, arthritis, and postoperative tissue infections
Eikenella corrodens
Fastidious, gram-negative coccobacilli that grows best in increased carbon dioxide with hemin
Eikenella corrodens
Eikenella corrodens risk factors:
Poor oral hygiene and oral surgery
Members are coccobacillary to short bacilli with squared ends that occur in pairs or short chains
Kingella
Grows on Thayer-Martin agar and can resemble Neisseria spp.
Kingella
Kingella grows on _____ and can resemble Neisseria spp.
Thayer-Martin agar
Kingella grows on Thayer-Martin agar and can resemble _____
Neisseria spp.
Associated with bacteremia and abscesses
K. dinitrificans
An important pathogen in pediatric population, causing degenerative joint and bone infection or osteoarthritis in children younger than three years
K. kingae
Soul glucose non-fermenter
Eikenella corrodens
The most common isolate of Pasteurella
P. multocida
Describe the colonies of Pasteurella
Gram negative, nonmotile, facultatively anaerobic coccobacilli that appear ovoid, filamentous or as bacilli
Pasteurella grows on _____ and _____, but not on _____
BAP and CAP
MAC
Produces non hemolytic colonies that may appear mucoid after 24 hours, followed by the production of a narrow green-to-brown halo around the colony after 48 hours, with a characteristic mushroom smell
P. multocida
Also known as Undulant fever, Mediterranean, Crimean, and Malta fevers
Brucella
Brucella is also known as _____
Undulant fever, Mediterranean, Crimean, and Malta fevers
The organism can gain entry to the body through aerosols, percutaneous or oral routes. Transmission through sexual contact and breastfeeding has also been reported.
Brucella
There are three stages of brucellosis infection:
- Acute infection
- Subchronic or undulant form
- Chronic form
Nonspecific symptoms (such as fever, malaise, headache, anorexia, myalgia, and back pain), occurs within 1-4 weeks of exposure
Acute infection
Undulating fevers (characterized by normal temperatures in the morning followed by high temperatures in the afternoon and evening), arthritis, and epididymo orchitis (inflammation of the epididymis and testis).
Subchronic or undulant form
Depression, arthritis, and chronic fatigue syndrome. The chronic form commonly manifests 1 year after exposure with symptoms.
Chronic form
Four commonly isolated species of Brucella
B. melitensis
B. abortus
B. suis
B. canis
The preferred sample for isolation for Brucella spp.
Blood
Bone marrow
Capnophilic member of the genus Brucella
B. abortus
Implicated in most human infections; the causative agent of tularemia
F. tularensis
A zoonotic disease also known as rabbit fever, deer fly fever, lemming fever, and water rat trappers’ disease
Tularemia
The most common form of the disease is characterized by ulcers at the site of inoculation and enlargement of the regional lymph nodes
Ulceroglandular
Appear as small, nonmotile, non-spore forming, gram-negative bacilli or coccoid bacteria that are strictly aerobic
Francisella
Agar where Francisella can grow
Chocolate agar, Modified Thayer-Martin, and Buffered charcoal yeast extract (BCYE) agar
The infectious dose of Francisella is about _____ making it highly infectious
50 organisms
Ubiquitous gram-negative bacilli
Legionella
Legionella is responsible for _____ of community acquired pneumonia
2 to 15%
Febrile disease with pneumonia
Legionnaire’s disease
Legionnaire’s disease incubation period
2-10 days
Characterized by dry cough, fever, headache, and myalgia
Legionnaire’s disease
Bacteremia, kidney failure, liver disorders, diarrhea, and central nervous system abnormalities can also be present
Legionnaire’s disease
Incubation period of Pontiac fever
2 days
Flu-like symptoms, these include fever headache and myalgia that resolves without medical intervention legionella can be present
Pontiac fever
Primary mode of transmission of Legionella
Inhalation of aerosolized water particles
Specimens for diagnosis of Legionella spp.
Sputum and bronchial washing
Detection of Legionella antigen in urine specimen using radioimmunoassay and enzyme immunoassay. What is this test?
Urine Antigen Test
Fluorescein isothiocyanate labeled antibodies bind to antigens on the cell surface, and the Ag-Ab complexes are detected using a fluorescent microscope. What is this test?
Direct Fluorescent Antibody test
Primary human pathogens of Bordetella
B. pertussis and B. parapertussis
Causes whooping cough or pertussis
Bordetella
An opportunistic pathogen, causing respiratory and wound infection
B. bronchiseptica
Small, gram-negative, aerobic bacilli or coccobacilli
Bordetella
Obligate aerobes that grow at 35-37 degrees
Bordetella
Bordetella are obligate aerobes that grow at _____
35 to 37 degree Celsius
Bordetella spp. that exhibits motility
B. bronchiseptica
Virulence factors of B. pertussis and B. parapertussis
- Filamentous hemagglutinin and pertactin
- Pertussis toxin
- Tracheal cytotoxin
Used to facilitate attachment to epithelial cell
Filamentous hemagglutinin and pertactin
Interferes with signal transduction within cells
Pertussis toxin
Promotes cell death
Tracheal cytotoxin
Three phases of disease of B. pertussis and B. parapertussis
- Catarrhal phase
- Paroxysmal phase
- Convalescent phase
– Nonspecific signs such as sneezing, cough, runny nose, and conjunctivitis can be present; infection is highly communicable.
- Respiratory distress can be seen in infants
Catarrhal phase
Sudden onset of sever, repetitive coughing followed by the characteristic “whoop” at the end of the coughing spell
Paroxysmal phase
Decrease in frequency and severity of coughing spells; patients recover within weeks or months
Convalescent phase
● A human disease with no animal reservoir or vector
● Acquired through respiratory droplet or direct contact with secretions
● One of the most highly communicable diseases of childhood
● Adults may or may not experience respiratory symptoms
Pertussis
● Respiratory tract pathogen of animals including dogs, in which it causes kennel cough
● Humans can acquire disease, such as those who have contact with animals or the immunosuppressed
B. bronchiseptica
Specimen of choice for Brucella spp.
Nasopharyngeal aspirates or swab
