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Micro: Haemohphilus, Bordatella, Pseudomonads


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Haemophilus influenza
blood loveing upper respiratory tract organism

causes invasive diseases preceede by URT infections w/ vague mild symptoms that progress to meningitis, pneumonia, septic arthritis, osteomyelitis, sepsis, pericarditis or epiglotitis
What are diseases caused by NON encapsulated Haemophilus influenza?
The unencapsulated form causes Otitis media, sinusitis, bronchitis
Which serotype of Haemophilus influenza causes the invasive diseases?
Serotype b (Hib)

*capsule b is BAD!
What is the most common cause of bacterial otitis media?
Streptococcus penuemoniae
What contributes to the pathogenecity of Haemophilus influenza?

IgA protease

Capsules are antiphagocytic- 6 antigenic types; type b makes up 95% of invasive diseases

endotoxin- not prominent feature
What lab tequniques would you use to isolate/identify Haemophilus influenza?
Gram stain of CSF

Slide agglutinations tests of CSF to detect polyribitol phosphate capsule (PRP)

X-V factor tests

Antibiotic susceptibility to determine best chemotherapy
What type of medium is needed to culture Haemophilus influenza?
grows on Chocolate (or any similar) enriched with hemin (X factor) and NAD (V factor)

CO2 incubation is required from some strains
What two factors are required for growth of Haemophilus influenza on blood agar?
NAD (V factor)

hemin (X factor)
Can you acquire immunity to Haemophilus influenza? if so, how?
YES Infante get passive protection from their moms

acquired immunity includes opsonic Ab and bacteriocidal Ab

adults have acquired immunity, but there is increased susceptibility in geriatric patients
Is there a vaccine for Haemophilus influenza?
vaccine is primarily polyribosylribitol phosphate (PRP) capsule of Hib covalently linked to T cell independent protien
there are other protein carriers vaccines( see notes)

side benefits of immunizations- it reduces passive carraige of Hib
How do you treat Haemophilus influenza?

treated w/ cephalosporin or chloramphenicol (some strains have acquired ampicillin resistance by plasmids)

rifampin is used for prophylactic treatment
Haemophilus parainfluenza?
this org is commonc in upper respiratory tract and must be differentiated from H. influenza
Haemophilus ducreyi: what disease does it cause?
Causes chancroid or soft chancre that are PAINFUL*

supporative ulcers, buboes- secondary lesions assoc. w/ kissing

*unlike syphilis lesions which are hard and painful
How is Haemophilus ducreyi diagnosed?
diagnosis is made on clinical picture, elimination of other sexually transmitted diseases

Gram stain of lesion and aspirates of buboes

culture growth is poor, may grow on chocolate
What STD may be confused with Haemophilus ducreyi?
What bacteria causes whooping cough?
Bordetella pertussis
What are the clinical characteristics of whooping cough?
this disease starts as a cold with inflammation of mucus membranes

it is followed by a persistant coughing state

coughs are sudden and severe w/ an inspiratory whoop as child tries to get air from a narrowed glottis
What are the pathogenic mechanisms of Bordetella pertussis?
non invasive infection of bronchial epithelium

filamentous hemagglutinin aids in attachtment

tracheal cytotoxin causes epithelial injury

pertussis toxin (lymphocyte promoting factor, promotes lymphocytosis and enhances attachment
How is Bordetella pertussis spread?
spread by droplet nuclei, highly infectious
Describe the Pertussis Toxin?
an A + B (Bind and Action)

ADP ribosylates reg proteins for cytoplasmic adenylate cyclase

* see notes about genetic variation of virulence genes
What type of media is used to grow Bordatella?
Culture of nasopharynx is most successful

Bordet- Gengou media w/ 10-15% blood in a potatoe starch base

10% charcoal base media

use a low conc of cephalosporin or other antiB to inhibit growth of normal throat flora
How is Bordetella diagnosed?
direct flourescent Abs

identification based on slide agglutination test or flourescent Ab test
Is there a vaccine for Whooping Cough?
DTP vaccine - diptheria and tetanus toxoids with whole cell pertussis

DTaP - diptheria and tetanus toxoids with acellular pertussis components
How is whoping cough treated?

AB treatment is of little vaule during thw whooping stage

erythromycin is used for preventative prophylaxis
What diseases does Pseudomonas aeruginosa cause in healthy people?
swimmers ear
skin infection from whirlpools
eye infections from contaminated contact lens solution
contribute to peritonitis
What diseases does P. aeruginosa cause in immunocomprimised?
cystic fibrosis - pneumonia

burn patients - septicemia

leukemic pts - septicemia

diabetics - otitis externa and gangrene
How is P. aeruginosa tranmitted?
only environment acquired, no person to person spread

org found in soil water, vegetation, and in humans
What makes P. aeruginosa virulent?
pili and polysacchride slime (alginate) for adherence

Toxin A - identical mode to diptheria toxin

Exotixin S - protease

Phospholipase - destroys cell membranes
Is there a vaccine for P. aeruginosa?
there is an experimental vaccine

immunity is poorly identified
How do you grow/ identify P. aeruginosa?
isolated from blood, pus, fluids

grows aerobicallly on any routine media (blood or MacConkey)

produces a greenwater souble pigment and a fruity odor

pyocin and serotypin schemes not usually done

* in CF pts isolates appear in mucoid colonies due to presence o polysacchride, alginate, capsule
How is P. aeruginosa treated?
by not getting it in the first place

very resistant to the normal antibiotics due to outer membrane porins
Burkholderia cepacia
formally cassified as a Psuedomonads

causes a lung infection in children with CF

very resistant to antibiotics
Burkholderia pseudomallei
formally cassified as a Psuedomonad

found in the tropics

causes pnuemonia, septicemia in soldiers during Vietnam

causes a disease called melioidosis
Stenotrophomonas maltophilia
formally cassified as a Psuedomonad

cause of nosocomial infections of wounds, UTs, respiratory tract, cystic fibrosis patients and neurotropenic (low neutrophils) patients
short gram negative bacilli

some strains may be confused with Neisseria in cases of urethritis

ubiquitis in nature

causes pneumonia, wound infections, septicemia, nosocomial infections
What are the leading causes of bacterial pneumonia in patients with AIDS?
#1 Streptococcus pneumoniae

#2 Haemophilus influenzae

#3 Pseudomonas aeruginosa

#4 Staph aureus
What are two life threatening diseases caused by H. influenzae?

What environmental bacterium is the cause of most oppurtunistic infections?
P. aeruginosa
Bacterial infections are the most frequent complication of hemodialysis patients. What are some of the bacteria that cause these infections?
P. aeruginosa

Stenotrophomonas maltophilia

Acinetobacter species
T/F most H. influenzae infections are caused by nonencapsulated thus nontypeable strains?
TRUE - earaches

incidence of disease cause by the un encapsulated strain is decreased dramatically since the advent of the vaccine

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