Lecture 9 - Gram negative bacteria 2 Flashcards
What is the ‘HACEK’ group?
A miscellanious fastidious Gram NEgative Rods
Where can ‘HACEK’ speces be found?
Members of the normal flora of oropharynx or urogenital tract
What types of conditions are ‘HACEK’ bacteria associated with?
Rare human infections (most commonly associated with subacute infecive endocarditis.
What is endocarditis?
Damage to a faulty valve by bacteria
What are ‘HACEK’ bacteria?
Haemophilus aphrophilus and paraphrophilus
Actinobacillus actinomycetemcomitans
Cardiobacteriumhominis
Eikenella corrodens
Kingella kingae
Which of the ‘HACEK’ group are aggregatibacter?
Haemophilus aphrophilus
Actinobacilus actinmycetemcomitans
What is the mortality rate of untreated endocarditis?
100% the bacteria destroys the valve which results in death
What is Pasteurella multocida?
Gram negative rods/coccobacillus
Where are pasteurella multocida associated with?
Normal flora of animals’ mouths particular cats and dogs
What type of wounds do pasteurella multocida predominate in?
Bite wounds
What kind of infections are bite wound infections?
polymicrobial
Aggressive, destructive, chronic infection of skin and subcutaneous tissues
Tendon sheathes joint cavities and bones can be infected
What kind of infection does bordetella pertussis do?
Whooping cough which is an upper respiratory tract infection which also infects glottis and trachea
How is bordetella pertussis transmitted?
VIa respiratory droplets
How does bordetella pertussis cause disease?
it creates a toxin that kills and irritates the upper respiratory tract
What kind of illness does bordetella cause in adults?
Adults dont get the typical 3 stage disease but they get inflammation of lining of upper respiratory tract. Damage left behind by toxin can cause coughing for long after initial infection
What kind of disease does brucella cause in humans?
Zoonotic infections for people who get in contact with farm animals (sheep cattle and goat)
What is the common name of the disease caused by brucellosis?
Undulant fever
How does brucellosis affect humans?
Disease of lymphatic tissue
Bone and joint infections
and chronic symptoms such as fever, sweats, myalgia, headache, and depression
What tissue does brucellosis affect?
Liver
Spleen
Lymph nodes
Bone marrow
Kidneys
Where can bartonella be found?
In saliva and nails of cats/kittens
What kind of disease does bartonella cause?
Cat scratch disease in people with normal immune systems
What are the symptoms of cat scratch disease?
initial lesion: papule/pustule/vesicle
Regional lymphadenopathy (commonly in the axilla)
What is campylobacter?
curved, spiral gram negative rods found in animals such as cattle, pigs, and chickens.
What are the 2 species of campylobacter that humans are commonly infected with?
Campylobacter jejuni
Campylobacter coli
How do people get C. jejuni?
From poorly cooked chicken.
What are the symptoms of infection with C.jejuni?
Self-limiting bloody diarrhoea and abdominal cramping fever.
Common cause of diarrhoea
What is the shape of helicobacter pylori?
helical gram negative rod
Where was the helicobacter pylori discovered?
In Perth by Dr Barry Marshall
Where does the helicobacter pylori bacteria live?
In mucous layer covering mucus secreting epithelium of stomach and duodenum
What does helicobacter pylori do in disease?
Major causative factor for duodenal ulcers and most gastric ulcers.
Major causative factor in gastro adeno-carcinoma and gastric lymphoma
How can ulcers caused by helicobacter pylori be treated?
Treating with acid suppressing drugs and antibiotics
Where can legionella typically be found?
Can grow in cooling towers and when water evaporates it takes legionella with it causing pneumonia
What is the pneumonia associated with legionella called?
legionnaires disease
What is the mortality rate of legionnaires disease?
20%
How is legionella acquired?
by inhalation of vapours containing leginoella.
Could also be acquired from pot plant mix
What legionella species is found in pot plant mix?
legionella longbeachae
What are the haemophilus species?
Haemophilus influenzae
Haemophilus parainfluenzae
Haemophilus aphrophilus and paraphrophilus
Haemophilus ducreyi
Which haemophilus influenzae strains are virulent?
The encapsulated strains
What are encapsulated haemophilus strains serotyped from?
antigenic differences and they are lettered a to g
What is the most common strain of haemphilus influenzae?
Type b
What kind of disease is haemophilus influenzae”
Rapidly fatal meningitis and septicaemia.
Serious sequelae in survivors
What is a sequela?
a condition which is the consequence of a previous disease or injury.
What kind of demographic is most commonly infected by haemophilus influenzae type b?
Children <18yo
What are the symptoms of haemophilus influenzae type b infection?
Epiglottitis
Inflammation and swelling of epiglottis
Rapid progression to laryngeal obstruction and asphyxiation
Why is haemophilus disease type b uncommon now?
Vaccine was introduced in 1992 in Australia
Are noncapsular non-typeable haemophilus influenzae pathogenic?
yes they cause bronchitis, sinusitis, and otitis media
What kind of infections do haemophilus parainfluenzae produce?
uncommonly cause mucosal infections and endocarditis
What kind of disease do haemophilus ducreyi cause?
Chancroid which is an STD
What are the symptoms of chancroid?
Haemophilus ducreyi infection results in:
Ulcerative genital lesions
Enlarged lymph nodes
Where does chancroid typically occur?
Tropical locations
What are the gram negative cocci?
Genus Neisseria
genus Moraxella
What are the gram negative coccobacilli?
Genus Kingella
Genus Acinetobacter
Genus Haemophilus
Genus Bordetella
Genus Brucella
Genus Pasteurella
What kind of arrangement are Neisseria?
Diplococci?
What are the species of Neisseria?
Neisseria meningitidis
Neisseria gonorrhoeae
Commensal Neisseria
Name an important virulence factor for neisseria meningitidis:
Polysaccharide capsule
What are the most serious disease causing serogroups of neisseria meningitidis?
A,B,C,W, and Y
Which serogroups of Neisseria meningitidis predominate Australia?
B until 2015 and now W is becoming more common
What does neosseria meningitidis do?
Rapidly fatal infection in previously healthy people
Purulent meningitis
Overwhelming septicaemia with purpuric rash
Meningitis and septicaemia together
MENINGITIS IS NOT NECESSARY FOR DIAGNOSIS
Where is neisseria meningitidis typically located?
carried in nasopharynx of 5 - 10% of population
In africa there is a subsaharan meningitis belt
What serogroups is there a vaccine for?
A, B (took a while to get), C, Y and W135
What is neisseria gonnorrhoeae?
gonnorrhoeae
What are the symptoms of gonnorrhoeae?
Urethritis (infection of the urethra)
Pharyngitis or anorectal infection
Bacteraemia (rare)
In females:
Cervicitis, purulent discharge
Salpingitis (infection of fallopian tubes)
Opthalmia neonatorum (infection of eyes of newborn infants)
What is the issue with commensal neisseriae??
Can be occassionally misdiagnosed as gonnorrheae
Where are commensal neisseria typically located?
Respiratory and occaionally genital tracts
Rare causes of different types of infection
What is moraxella catarrhalis?
Gram negative diplococci on gram stain
Where are Moraxella catarrhalis typically located?
They are commensals of upper respiratory tract and female genital tract
What conditions can Moraxella catarrhalis cause?
Lower respiratory tract infections in adults with underlying lung disease (exacerbates previous lung issues)
Otitis media and sinusitis in children
What is the difference between self-limiting diarrhoea and normal diarrhoea?
Self-limiting goes away on its own
