Bacteriology Exam 7 (Neisseria, Haemophilus, Other) Flashcards
What is the main pathogen of Haemophilus species?
H. influenzae
Haemophilus growth conditions
Facultative anaerobes at 35-37C with 5-7% CO2
Normal flora vs non-normal flora Haemophilus
Normal flora: H. influenzae, H. parainfluenzae
Never normal: H. ducreyi (STD)
Where are common infection sites for Haemophilus?
Ear, sinus, bronchitis, pneumonia, conjunctivitis
What is the Haemophilus sp. that causes STD and is never normal flora?
H. ducreyi
What is Factor V and what is Factor X?
Factor V is NAD
Factor X is Hemin
Haemophilus: Non-motile or motile?
Non-motile
Haemophilus gram stain
Pleomorphic GNR (coccobacillus or short GNR)
Haemophilus: oxidase and catalase
oxidase pos
catalase pos
T/F: Haemophilus will grow on SBA.
False; only on CHOC. This is why extra colonies seen on CHOC and no other plates should be suspicious for Haemophilus.
What 2 Haemophilus are beta hemolytic?
H. haemolyticus and H. parahaemolyticus
Haemophilus will not grow on Sheep blood agar, but which blood agars can they grow on and why?
Horse and Rabbit blood agars because X and V factors are readily available
Why will satellitism allow Haemophilus to grow on SBA?
S. aureus/S. pneumoniae/Neisseria have V factor as a product of their metabolism, so streaking this will allow Haemophilus to use Factor V to grow, and SBA already has X factor
How does the porphyrin test help us to identify Haemophilus species?
H. parainfluenzae is positive (red/orange color) - contains porphobilinogen and can synthesize heme which is why it only requires factor V to grow
H. influenzae is negative - needs both X and V given to it to grow
Which Haemophilus species are porphyrin test positive? What does this mean?
H. parainfluenzae and H. parahaemolyticus - they can synthesize heme meaning they only need factor V to grow
What Haemophilus species only need factor V to grow?
H. parainfluenzae
H. parahaemolyticus
What Haemophilus species only need factor X to grow?
H. ducreyi
What Haemophilus species need both factor X and factor V to grow?
H. influenzae
H. haemolyticus
H. aegyptius
Rapid NH test MacFarland
3.0 MacFarland (heavier because fastidious)
What does Haemophilus influenzae smell like on agar?
Mousy or bleachlike
T/F: Haemophilus influenzae is considered normal flora.
True
What can Haemophilus influenzae cause?
Ear infections, sinusitis, conjunctivitis, bacteremia
What can Haemophilus influenzae nonencapsulated/non-typeable strains cause?
Localized infections - Ear infections, sinusitis, conjunctivitis, bacteremia or bronchitis/pneumonia in older patients
What can Haemophilus influenzae encapsulated/typeable strains cause?
More serious/more invasive infections - meningitis, septic arthritis, pneumonia, cellulitis, epiglottitis
T/F: Haemophilus parainfluenzae is normal flora.
True; most haemophilus sp. normal flora is this species
What can Haemophilus parainfluenzae cause?
Rare endocarditis following dental procedures
What is the causative agent of “pink eye”?
H. aegyptius
What can H. aegyptius cause?
Pink eye, Brazilian Purpuric Fever
What does H. ducreyi cause?
Chancroid STD - Genital Ulcer Disease
What does H. ducreyi look like under a microscope?
School of fish or railroad tracks gram stain
What species uses the Quad Plate and what is it?
Haemophilus - four quadrants (I has X only, II has V only, III has X and V, and IV with horse blood to look at hemolysis)
Neisseria gram stain/wet mount
kidney bean shaped, gram neg diplococci, non-motile (may also be seen inside of WBCs)
What are the two major pathogens of interest in Neisseria sp.?
N. gonorrhea and N. meningitidis
T/F: N. gonorrhoeae is the second most commonly reported STD in the US
True
Where can Neisseria sp. be found?
Mucous membranes of respiratory and urogenital tracts
T/F: N. meningitidis can be considered normal flora.
True
What does N. meningitidis cause?
Fatal bacterial meningitis in children or IMD
What collection procedures are unacceptable for Neisseria and why?
Cotton tipped/wooden swabs and calcium alginate swabs because they can be inhibitory
What agars are ideal for Neisseria recovery?
MTM and Martin Lewis Agar, CHOC
What conditions do N. gonorrhoeae and N. meningitidis grow best in?
capnophilic conditions (3-7% CO2) with high humidity 35-37C
Neisseria oxidase/catalase
Pos
N. gonorrhoae sites of infection
Columnar/transitional epithelial cells of humans - can cause disseminated infections such as arthritis in the knees
N. gonorrhoeae is more like to show symptoms in males or females?
Males
Disseminated Gonococcal Infection
Purulent arthritis and rare septicemia, can be found in synovial fluid causing arthritis
What is in MTM that allows for Neisseria to be selected for?
Vancomycin - inhibits GP
Colistin - inhibits GNR
Nystatin - Antifungal
Trimethoprim - stops Proteus
What diseases can N. meningitidis cause?
Disease only occurs when normal flora spreads to sterile body site - can cause meningitis, bacteremia, pneumonia, Waterhouse Frederichsen Syndrome
Neisseria A strain is associated with what?
Neisseria B strain?
A - pandemics
B - community acquired disease in the US
Signs/Symptoms of meningitis
Fever, frontal headache, stiff neck, photophobia
What is Waterhouse Frederichsen Syndrome? What causes it?
Hemorrhage into adrenal glands caused by N. meningitidis
Neisseria weaveri
Normal oral flora in dogs, can be infected through a dog bite
What sugars can N. gonorrhoeae metabolize for the rapid NH test?
Only glucose
What sugars can N. meningitidis metabolize for the rapid NH test?
Glucose and maltose
What sugars can N. lactamica metabolize for the rapid NH test?
Glucose, maltose, and lactose
What sugars can N. sicca metabolize for the rapid NH test?
Glucose, maltose, and sucrose
How can M. catarrhalis be differentiated from Neisseria?
M. catarrhalis does not metabolize any sugars and it is also DNase positive.
Special features of Achromobacter
Aerobic, non-fermenting, gram-negative, nonsporulating, mostly motile GNR with peritrichous flagella
Achromobacter is an ________ opportunistic pathogen.
Environmental
What will Achromobacter/Rhizobacter grow on?
BAP/CHOC/MAC/THIO/BHI
What Achromobacter has been recovered from patients with cystic fibrosis?
xylosoxidans
Achromobacter Approach to ID: catalase, oxidase, indole, morphology, motility
Catalase pos
Oxidase pos
Indole neg
Flat, spreading, non-pigmented with feathery edge
Fruity odor
Motile
Achromobacter xylosoxidans special features
Common cause of ear infections
Reduces nitrate to nitrite
Oxidizes xylose and glucose
Grows on cetrimide agar
Grows at 42C
Resistant to aminoglycosides
Rhizobacterium epidemiology
Environmental opportunistic pathogen; exposure to contaminated medical devices mostly seen in cystic fibrosis patients
Notable features of the genus Alcaligenes
Oxidase positive, Catalase positive, non-glucose utilizers, NLF, GNR, motile with peritrichous flagella
Alcaligenes epidemiology
Environmental opportunistic pathogen recovered from CF patients from contaminated medical devices
Alcaligenes faecalis notable features
Produces a sweet odor reminiscent of juicy fruit or apple cider, slightly alpha hemolytic
T/F: Eikenella can grow on MAC
FALSE
T/F: Eikenella is a member of HACEK
TRUE
What is HACEK?
Group of bacteria known to cause subacute bacterial endocarditis in immunocompromised patients
Eikenella corrodens epidemiology
Normal microbiota of the human oral cavity associated with periodontitis and complications with dental procedures; recovered from human bites known as “clenched-fist wounds”
What group of patients are more at risk for Eikenella infections?
Diabetic patients because of the daily microtrauma to their skin
The most recognizable feature of E. corrodens towards Identification:
Bleachlike odor with colonies that pit the agar and demonstrates slight yellow hue after several days
Does not utilize any carbohydrates
Ox positive
Catalase neg
Reduces nitrate to nitrite
Hydrolyzes ornithine and lysine
T/F: Moraxella grows well on MAC
FALSE
Moraxella gram stain
Coccobacilli or short GNR that may appear gram-variable
Moraxella catarrhalis epidemiology
Normal microbiota of the upper resp tract; occasionally colonizes female genital tract
What diseases can Moraxella catarrhalis cause in children?
Sinusitis, otitis media, conjunctivitis, URI, pneumonia
ID of M. catarrhalis
Ox pos
Cat pos
GNCB
B-lactamase pos
Negative for all carb fermentation
Hockey puck consistency on agar
What is the purpose of butyrate esterase testing? What organism is this useful for? What does a positive reaction look like?
Used for the ID of M. catarrhalis; Positive reaction is blue if they possess the enzyme butyrate esterase
How to differentiate M. catarrhalis from Neisseria sp.
M. cat is DNase positive
Neisseria is DNase negative
M. cat also does not utilize ANY sugars
