fastidious gram negative rods Flashcards
fastidious gram negative rods are cultured on ___ agar
chocolate
bartonella spp.: name the four species
b. bacilliformis, b. quintana, b. henselae, b. clarridgeiae
b. bacilliformis: clinical presentations
carrion’s disease = oroya fever (high fever = severe anemia due to RBC infection)
character skin rash
spread by sandflies
b. quintana: clinical presentations
trench fever, aids related conditions, endocarditis
b. henselae: clinical presentations
cat scratch disease, aids related condition, endocarditis
b. clarridgeiae: clinical presentations
cat scratch disease
bartonella spp.: diagnosis
serology, histology, culture
haemophilus influenzae: culture
chocolate agar
haemophilus influenzae: character
requires hemin (X factor) and NAD (V factor) to grow
throat carriage
haemophilus influenzae: transmission
respiratory droplets, close contact
haemophilus influenzae: virulence factors
some strain possess antiphagocytic capsules (a-f, b is the most common; also in sg the most common type is the non encapsulated type)
haemophilus influenzae: clinical presentations
encapsulated infections: meningitis, acute epiglottitis, septicaemia, cellulitis, pneumonia, osteomyelitis, septic arthritis
non-encapsulated infections: invasive (meningitis and septicaemia in neonates; pneumonia in older age groups) and non-invasive (urti)
haemophilus influenzae: diagnosis
blood culture
haemophilus influenzae: treatment
ceftriazone; most species are resistant to penicillin since they produce beta lactamase
haemophilus influenzae: prevention
conjugate vaccines against type b for children and at risk patients
chemoprophylaxis of rifampicin and vaccine for prevention of secondary cases
haemophilus ducreyi: histology + character
“shoal of fish” appearance
x (iron, hemin) dependent growth
haemophilus ducreyi: culture
chocolate agar
haemophilus ducreyi: transmission
sexually transmitted disease
haemophilus ducreyi: clinical presentations
chancroid (painful genital ulcer + enlarged inguinal lymph nodes that may suppurate and ulcerate)
haemophilus ducreyi: diagnosis
culture, pcr
haemophilus ducreyi: treatment
several agents effective
hacek group
group of gram negative bacteria associated with endocarditis
haemophilus parainfluenzae aggregatibacter actinomycetemcomitans cardiobacterium hominis eikenella corrodens kingella kingae
klebsiella granulomatis: transmission
sexually transmitted disease
klebsiella granulomatis: clinical presentations
granuloma inguinale = donovanosis
subcutaneous nodules break down to painless ulcers, gradual enlargement of ulcers with prominent granulation tissue, tissue loss and scarring
spread to inguinal region causes periadenitis (pseudo bubo) and pelvic fibrosis
klebsiella granulomatis: diagnosis
“donovan bodies” seen in macrophages in tissues smears
bordetella spp.: name the 2 species
bordetella pertussis, bordetella parapertussis
bordetella spp.: culture
mercury droplet colonies on bordet-gengou agar
bordetella spp.: transmission
respiratory droplets
bordetella spp.: clinical presentations
whooping cough
catarrhal stage: resemble other respiratory infections
paroxysmal stage: paroxysmal cough (lungs emptied in a series of cough before dragging in a fresh breath through a narrowed throat which produces the “whoop”) - once this stage is established, may last afew months
bordetella spp.: diagnosis
pernasal swab for culture, pcr
bordetella spp.: treatment
erythromycin - reduces severity of illness if given before the paroxysmal stage
bordetella spp.: prevention
effective vaccines available in national childhood immunisation schedule
francisella tularensis: character
naturally infects animals like rodents and rabbits
francisella tularensis: transmission
handling animal carcasses, arthropod vector - respiratory, oral routes
francisella tularensis: clinical presentations
tularaemia: infection of skin, eye, lymph nodes and pneumonia
legionalla pneumophila: culture
buffer charcoal yeast extract agar (B-CYE): needs cysteine and iron
legionella pneumophila: character
environmental bacteria that grows in water (e.g. in cooling tower of air conditioning plant), poorly maintained water supplies
legionella pneumophila: transmission
infectious aerosol from colonised water source dispensers (not person to person, not airborne)
legionella pneumophila: clinical presentations
legionnaire’s disease: severe pneumonia frequently accompanied by confusion or extra pulmonary manifestations
pontiac fever: brief influenza-like illness, less dangerous
legionella pneumonia: diagnosis
immonofluorescent stain on sputum sample or bronchoalveolar lavage
antigen detection in urine only for serogroup 1
serology only for serogroup 1
legionella pneumonia: treatment
high dose iv erythromycin alone or + rifampicin
pasteurella multocida: character
present in mouth and throat of many animals (especially cats)
pasteurella multocida: transmission
animal bites
pasteurella multocida: clinical presentations
cellulitis, osteomyelitis
pasteurella multocida: treatment
penicillin, co-amoxiclav (infected bites are often polymicrobial)
brucella spp.: character
naturally infects a variety of farm animals
brucella spp.: transmission
zoonosis (direct contact with infected animals or consumption of contaminated meat/milk/cheese)
brucella spp.: clinical presentations
brucellosis = maltese fever pyrexia of unknown origin, undulant fevers chronic brucellosis (low grade fever with malaise) bone and joint symptoms, osteomyelitis endocarditis
brucella spp.: diagnosis
blood culture, serologu
colonies positive for urease
brucella spp.: treatment
doxycycline + streptomycin
brucella spp.: prevention
pasteurisation of milk kills brucella spp., vaccinate farm animals
acinetobacter baumannii: character
environmental
normal skin flora
acinetobacter baumannii: clinical presentations
nosocomial pneumonia (often multi resistant)
name the 3 bacteria of yersinia spp.
y. enterocolitica, y. pseudotuberculosis
y. pestis
y. enterocolitica, y. pseudotuberculosis: clinical presentations
gastroenteritis, mesenteric lymphadenitis, terminal ileitis, septicaemia
y. enterocolitica, y. pseudotuberculosos: diagnosis
culture from stool or blood, serology
yersinia pestis: histology + character
saftety pin appearance
infects rodents
yersinia pestis: transmission
zoonosis (often through the bite of rat flea), respiratory droplets
yersinia pestis: clinical presentations
bubo formation (painful swelling of lymph nodes) with subsequent invasion of bloodstream giving rise to pneumonia and septicaemia
yersinia pestis: diagnosis
microscopy and culture of sputum or blood
