(F) Lesson 12: Haemophilus and Other Fastidious Bacteria (Part 1) Flashcards
One major characteristic of how Haemophilus and other gram-negative bacteria are grouped depends on their ____
Gram staining results
Family of Haemophilus (including Actinobacillus, Pasteurella, and Aggregatibacter)
Pasteurellaceae
- Are small, non-motile, pleomorphic gram-negative
- Most are facultative anaerobes and obligate parasites
- Inhabitants of the upper respiratory tract (URT) of humans and animals (except Haemophilus ducreyi)
- 13 spp identified and 8 are associated with humans
Haemophilus
- A key identifier for the members of the Pasteurellaceae family
Non-motility
- Means varying morphology; can appear as coccobacilli
Pleomorphic
- They do not require CO2, but its presence enhances the growth
Facultative Anaerobes
- They require CO2 to grow
Obligate Anaerobes
- This type of parasite depends on others for nutrition
Obligate parasites
T or F: All members of Haemophilus come from humans.
F (some come from animals)
Members of HACEK?
- Haemophilus
- Aggregatibacter
- Cardiobacterium
- Eikenella
- Kingella
- This is the key similarity of the members of HACEK.
Usual causes of bacterial endocarditis
T or F: All of the members of HACEK are normal biota.
F (most are normal biota but some are really common human pathogen)
T or F: Not all members of HACEK come out as bacilli since some come out as coccobacilli.
T
- They tend to require a certain nutrition or supplement to grow in a media
Fastidious
Identify the species based on the description.
Fastidious, hemophilic?
Clue: 1 answer
Haemophilus spp.
Identify the species based on the description.
Fastidious fermenters and non-fermenters?
Clue: Three answers
- Haemophilus aphrophilus
- Eikenella spp.
- Capnocytophaga spp.
Identify the species based on the description.
Fastidious anaerobes?
Clue: Three answers
- Bacteroides spp.
- Fusobacterium spp.
- Prevotella spp.
Identify the species based on the description.
Non-fastidious fermenters of carbohydrates?
Clue: 1 answer
Enterobacteriaceae spp.
Identify the species based on the description.
Non-fastidious non-fermenter of carbohydrates?
Clue: Two answers
- Pseudomonas spp.
- Acinetobacter spp.
The 8 organisms of Haemophilus associated with humans.
- H. influenzae
- H. aegyptius
- H. ducreyi
- H. parainfluenzae
- H. haemolyticus
- H. parahaemolyticus
- H. paraphrohaemolyticus
- H. pittmaniae
What are the three (3) common human pathogens under Haemophilus?
- H. influenzae
- H. aegyptius
- H. ducreyi
What are the five (5) organisms under Haemophilus that are found in normal biota?
- H. parainfluenzae
- H. haemolyticus
- H. parahaemolyticus
- H. paraphrohaemolyticus
- H. pittmaniae
Haemophilus came from what two Greek words meaning?
Haemo (blood) + Philo (love)
- Protoporphyrin IX or hemin or hematin
- In BAP and CAP preparation, it uses the same procedures
- However, in preparing BAP, the mixture is cooled down to a lukewarm temperature after autoclaving. Its red color is due to the intact RBCs
- In CAP, blood is immediately added to the medium after autoclaving, lysing the RBCs causing the change in color from red to brown.
Factor X
- NAD or NADP
- Found in the blood
Factor V
Growth of Haemophilus is enhanced in?
5-10% CO2
They exhibit ____ around S. aureus.
Satellitism
- Happens due to the beta-hemolytic property of S. aureus that lyses the RBC, allowing the growth of Haemophilus spp.
Satellitism
Haemophilus are (positive/negative) in catalse, oxidase, nitrate reduction, and hemolysis on 5% sheep/horse/rabbit blood agar (SBA, HBA, RBA).
Positive
- This type of agar contains NADases that lyse NAD.
Sheep Blood Agar
- Medium of choice for Haemophilus since it contains NAD, liberated Factor X from lysed RBCs in CAP
HCA or Horse Chocolate Agar Plate
Known with the common name of Pleiffer’s Bacillus
Haemophilus influenzae
Haemophilus influenzae
It was after the development of ____ that it became apparent that influenza was caused by a virus and the actual role of H. influenzae was that of a secondary/opportunistic invader.
Viral culture techniques
Haemophilus influenzae
It was after the development of viral culture techniques that it became apparent that influenza was caused by a virus and the actual role of H. influenzae was that of a ____.
Secondary or oppotunistic invader
Haemophilus influenzae
This makes the organism more pathogenic; mechanisms on how they can illicit diseases greatly.
Virulence Factor
Haemophilus influenzae
- Used in serotyping, it has 6 antigenically distinct serologic groups: a, b, c, d, e, and f based on differences in the capsular polysaccharide
- For its antiphagocytic property and anticomplementary activity
- Not present in all H. influenzae
Capsule
Haemophilus influenzae
The six (6) antigenically distinct serologic groups are based on differences in their?
Capsular polysaccharide
Haemophilus influenzae
- This the most invasive serotype since it contains a unique polymer: ribose, ribitol, and phosphate (polyribitol phosphate or polyribitol ribose phosphate).
Hib or serologic type B
Haemophilus influenzae
- Protection from the phagocytic activity by phagocytes
Antiphagocytic
Haemophilus influenzae
- Complements can’t attach to the organism, membrane attack complexes can’t be executed
Anticomplementary
Haemophilus influenzae
These types of Haemophilus do not contain capsules.
NTHi or non-typable H. influenzae
Haemophilus influenzae
This particular virulence factor is unique to Haemophilus influenzae.
Immunoglobulin A (IgA) Proteases
Haemophilus influenzae
- Inhibits human secretory IgA found in body secretions
- Since the Haemophilus spp. reside in the URT and there are a lot of secretions in the URT
Secretory IgA
Haemophilus influenzae
- Sometimes organisms may contain pili for attachment
- Significant in the type of infection produced by an organism
Adherence mechanisms
Haemophilus influenzae
- ____ is non-adherent (no pili)
- They tend to spread throughout the body, producing systemic infection
- There is no organ of infection
Hib
Haemophilus influenzae
- ____ are adherent
- Produces localized infection (better compared to Hib)
NTHi