(F) Lesson 12: Haemophilus and Other Fastidious Bacteria (Part 2) Flashcards
- Composed of Haemophilus, Aggregatibacter, Cardiobacterium, Eikenella, Kingella
- Most are part of the normal biota of the oral cavity and URT
- All are related to bacterial endocarditis
- Fastidious, facultative anaerobes, enhanced growth under presence of CO2
HACEK group
ACEK are ____ which means slower or poorer growing.
Dysgonic
T or F: The HACEK group includes those with immunocompromised state or those that are called as opportunistic pathogen.
T
The HACEK group are related to bacterial endocarditis due to their?
Predilection for attachment to heart valves
Familiarize yourself with the risk of infection for the HACEK group.
- Tooth extraction
- History of endocarditis
- Gingival surgery
- Heart valve surgery
- Mitral valve prolapse
- Comes from the Greek words aphros and philia which means foam-loving or desiring high concentration of CO2
- Found in dental plaque and gingival scraping
- Reclassification of H. aphrophilus and H. paraphrophilus due to molecular techniques
Aggregatibacter aphrophilus
- Formerly part of actinobacillus
- Divided into 6 serotypes: A to F
- Etiologic pathogen for periodontitis
- Has two major virulence factors: collagenase and leukotoxin
Aggregatibacter actinomycetemcomitans
Aggregatibacter actinomycetemcomitans
These serotypes (3) are the most common causative agents of infection.
A, B, C
Aggregatibacter actinomycetemcomitans
This virulence factor is for the destruction of collagen.
Collagenase
Aggregatibacter actinomycetemcomitans
This virulence factor is against WBCs and has something to do with anti-phagocytosis.
Leukotoxin
Colony of Aggregatibacter actinomycetemcomitans after 48 hours?
`
Star-shape with 4 to 6 points
T or F: The colony of Aggregatibacter actinomycetemcomitans may be observed with the naked eye.
F (use a microscope or stereomicroscope in LPO or scanner)
Drug of choice for Aggregatibacter actinomycetemcomitans?
Penicillin and an aminoglycoside (combined)
Alternative drugs for Aggregatibacter actinomycetemcomitans?
- Third generation cephalosporins
- Quinolones
- Chloramphenicol
- Tetracycline
Resistance of Aggregatibacter actinomycetemcomitans to ____ and ____ common.
Vancomycin and erythromycin
What are the two species of Cardiobacterium?
- Cardiobacterium hominis
- Cardiobacterium valvarum
Which Cardiobacterium spp. is more related to bacterial endocarditis?
Cardiobacterium hominis
- Part of the normal biota
- Has agar pitting
- Infects the aortic valve more than other HACEK members
Cardiobacterium hominis
Drug of choice for Cardiobacterium hominis?
Penicillin with an aminoglycoside
Cardiobacterium hominis is sensitive to what drugs?
- Beta-lactam antibiotics
- Chloramphenicol
- Tetracycline
Cardiobacterium hominis has a variable response to what drugs?
- Aminoglycosides
- Erythromycin
- Clindamycin
- Vancomycin
- Part of the normal biota
- Associated with human bites or fights (clenched fist wounds)
- Opportunistic to immunocompromised individuals, producing periodontitis, meningitis, empyema, pneumonia, osteomyelitis, arthritis, and postoperative tissue infections
- The least common isolate among the HACEK group for endocarditis
- Called this because of corrosion seen in its agar pitting and yellow pigment
Eikenella corrodens
Eikenella corrodens is sensitive to what drugs?
- Penicillin
- Ampicillin
- Cefoxitin
- Chloramphenicol
- Carbenicillin
- Imipenem
Eikenella corrodens is resistant to what drugs?
Clindamycin and other narrow-spectrum cephalosporin
- It resists in decolorization in G/S, appearing as G(+)
- Major G(-) bacterium isolated from degenerative joint and bone infections (osteoarthritis) in children
Kingella kingae
What are the four members of the Kingella species?
- Kingella kingae
- Kingella denitrificans
- Kingella oralis
- Kingella potus
Which member of the Kingella species is related to endocarditis?
Kingella kingae
Kingella kingae’s ability to resist decolorizatuon is not due to what?
Peptidoglycan layer
Color of the colonies of Kingella kingae?
Yellow brown
T or F: Kingella kingae is resistant to most agents, including penicillin.
F (susceptible)
The five (5) identified species of Capnocytophaga spp. that are part of the oral microbiota
- Capnocytophaga ochracea
- Capnocytophaga gingivalis
- Capnocytophaga sputigena
- Capnocytophaga haemolyticus
- Capnocytophaga granulosa
This species of Capnocytophaga spp. is the only one that tests negative for oxidase and catalse.
Capnocytophaga granulosa
- Not as commonly involved in endocarditis as they are in septicemia
- G/S: thin and often fusiform (pointed ends) resembling Fusobacterium spp.
- Motile organisms with a gliding motility
- On the agar: yellow-orange
Capnocytophaga spp.
- Positive for: Sucrose, glucose, maltose, lactose, nitrite, and esculin
- No growth on TSI without enrinchment
- Non-hemolytic
Capnocytophaga spp.
This is the only beta-hemolytic organism from Capnocytophaga spp.
Capnocytophaga haemolytica
Capnocytophaga spp.
The two zoonotic species found in the cat/dog oral cavity from bite wounds.
- Capnocytophaga canimorsus
- Capnocytophaga cynodegmi
Drug of choice for Capnocytophaga canimorsus and Capnocytophaga cynodegmi?
Penicillin
The Capnocytophaga spp. are susceptible to what drugs?
- Imipenem
- Erythromycin
- Clindamycin
- Tetracycline
- Chloramphenicol
- Quinolones
- Beta-lactams
The Capnocytophaga spp. are resistant to what drugs?
Aminoglycosides
- Has 17 spp, but not all are related to man
- (+) catalase, oxidase, glucose
- (+) CHOC with grayish colonies
- (-) MAC
- (+) SBA (BAP) w/o satellitism, non-hemolytic, mucoid, narrow green to brown w/ halo around the colony
- (+) bipolar staining in G/S with a safety pin appearance
Pasteurella spp.
What is the zoonosis of Pasteurella spp. and what are the involved organisms?
Systemic and cutaneous infections caused by Pasteurella canis, Pasteurella stomatis, and Pasteurella dagmatis
The most common isolate related to human infection involving the Pasteurella spp.
Pasteurella multocida
Familiarize yourself with the differential characteristics of Pasteurella spp.
Go mo na yan, it’s in the transes!
T or F: Most of the Pasteurella spp. are zoonotic, but due to their proximity to dogs and cats, humans can get infected.
T
- The CDC categorizes them as category B agents since they can easily disseminate, cause moderate morbidity but low mortality
- Under BSL-3 requiring many precautionary measures
- Facultative intracellular pathogens
- Colonies: smooth, raised, translucent
- (+) Rose Bengal Test and 2-mercaptoethanol (2-ME) agglutination Test
Brucella spp.
What are the four members of the Brucella spp?
- Brucella melitensis
- Brucella abortus
- Brucella suis
- Brucella canis
Best media for Brucella spp.?
- Castañeda broth
- TSB (Trypticase Soy Broth)
Selective media for Brucella spp?
Wisconsin medium
This enhances the growth for Brucella spp.
Erythritol
What is the disease associated with the Brucella spp?
Brucellosis
Identify the clinical stage of Brucellosis.
Nonspecific symptoms (fever, malaise, headache, anorexia, myalgia, and back pain)
Acute
Identify the clinical stage of Brucellosis.
Undulating fevers (normal temp in the AM, high temp during PM), arthritis, and epididymoorchitis
Subchronic
Identify the clinical stage of Brucellosis.
Depression, arthritis, chronic fatigue syndrome
Chronic
Familiarize yourself with the differential characteristics of Brucella spp.
Nasa transes again hehe.
T or F: Natural hosts of Brucella spp. are usually humans.
F (animals, hence they are zoonotic)
- Categorized by the CDC as Category A agents
- Can pose a risk to national security because they can be spread through person-to-person contact or are easily disseminated and result in high mortality rates, leading to a potentially great public health impact and public panic
- BSL-3
- Fastidious, facultative intracellular
- (-) oxidase, urease, satellite, X&V test
- Weak (+) catalase and beta-lactamase activity
Francisella spp.
Francisella spp. requires the supplementation of what?
Cysteine, cystine, or thiosulfate
Familiarize yourself with the media used for Francisella spp.
- CHOC
- Modified Thayer-Martin
- Buffered Charcoal Yeast Extract (BCYE) agar
- Mueller-Hinton agar
- Trypticase Soy Broths (TSB)