Microbiology review Flashcards
1-3 weeks after patients are exposed
Catarrhal phase- rhinorrhea, watery eyes, fever
paroxysmal phase- whoop like cough, blue faces after coughing spasm
complication for pneumonia
Bordetella pertussis
gram negative non motile capsulate rod facultative anaerobe severe bronchopneumonia cavitary lesions currant jelly sputum
CAP and HAP
alcoholic, lives on streets
lobar pneumonia
klebsiella pneumonia
gram negative grows on chocolate auger dplococci catalase and oxidase positive pneumonia especially in the elderly otitis media
moraxella catarrhalis
aerobic gram negative kidney shaped diplococci capsuele
grows on thayer-martin media, chocolate agar
oxidase positive
transmitted via resp droplets
seen in dorm, military barrics, outbreak of meningitis
commensal of the human upper resp tract
pneumonia
septicemia
septic arthritis, pericarditis, etc.
can lose limbs
Diagnosis:
Gram stain from CSF
CSF PCR
CSF culture
Treatment:
Penicillin
Prevention:
treat contacts with rifampin
neisseria meningitidis
if not treated–> systemic disease in 70-90%
morbidity- limb loss, hearing loss, long term neuro disability
aerobic gram negative rod
produces pyocyanin (blue green pigment on media)
sputum is bright fluorescent green
nosocomial pathogen - picked up in hospital or nursing home
seen in hospitalized patients, ventilators, nursing homes, hot tubs, swimming pools
most common cause of otitis externa
seen in puncture wounds in tennis shoes
exotoxins, endotoxins, pili, flagella, proteases (all the virulence factors!!)
treated with two or more broad spectrum antibiotics (cephalosporin, aminoglycosides)
(levofloxacin, gentamicin)
pseudomnas aeruginosa
gram negative obligate intracellular bacteria
macrophages are the principal host cell
diseases –> psittoacosis (bird fancier’s pneumonia), atypical pneumonia, febrile illness
Aerosolized bird secretions and dust
treatment: tetracyclines, macrolides, fluoroquinolones
prevention –> 30 day quarantine of birds before being sold in the US
chlamyodophila psittaci
common infection in children under 5
80% of adults are seropositive
atypical pneumonia*** -incubation of several weeks -nonproductive cough -preceded by congestion, sore throat, hoarseness headaches
exam- crackles and rhonci
normal white count
pnumonitis on CXR
prolonged course
Diagnosis:
serology
Treatment:
tetracyclines
macrolides
fluoroquinolones
chlamydophilia pneumoniae
Q fever
gram negative hosted in monocytes
incompletetly elimated after acute infection
endocarditis
lives in mammals, birds and ticks
major outbreaks have been related to sheep and goats and associated during lambing season
if a female develops this infection, she can get a chronic uterine infection which will prevent pregnancy (spontaneous abortions)
cerebral emboli, renal insufficiency, splenomegaly, hepatomegaly
diagnosis:
serology
treatment:
- doxycycline x2 weeks in acute cases
- doxycycine + hydroxychloroquine (increases phagosomal pH) for 18-36 months for endocarditis
coxiella burnetii
prolonged fever of unknown origin pneumonia hepatitis rash meningitis, encephalitis meningoencephalitis peripheral neuropathy pericarditis, myocarditis
Q fever
infectious zoonosis
small aerobic pleomorphic gram negative bacillus
rabbits, squirrels, muskrats
direct contact with infected animal tissue
ingestion of contaminated water or meat
Clinical manifestations:
- ulceroglandular- fever, swollen nodes, ulcer formation, sore throat, infiltrates
- glandular- fever, lymphadenopathy
- oculoglandular
- typhoidal- fever only
- oropharyngeal- painful exudative pharyngitis and tonsillitis, pharyngeal ulcers
- pnuemonic - dry cough, fever, pleural effusion, dyspnea, sore throat, hilar adenopathy, peribronchial infiltrates
francisella tularensis
spore forming gram positive non motile rod
aerobic or facultatively anaerobic
catalase positive
grows on sheep agar
zoonotic infection from goats, sheep, cattle, antelope, pigs, horses, etc.
Clinical manifestations inhalations: -mediastinal widening ** -pleural effusions -rapidly fatal if not treated with antibiotics and drain pleural effusion
bacillus anthracis
gram negative coccobacillus
microaeorphilic
non motile
non spore forming
prairie dogs are a common host
Clinical manifestations:
Bubonic= swollen, tender lymph nodes (buboes) at site of initial infection, fever, chills, body aches, headaches, untreated–> confusion, delirium
Septic = DIC, hypotension, renal failure and ARDS type picture
Pneumonic = highly fatal, often die within 24 hour period, fever, cough, chest discomfort, resp distress
yersinia pestis
treatments?
spirochete
silver staining or dark field microscopy
rodents, dogs, pigs, cattle and sheep
weil’s disease
pulmonary hemorrhage syndrome
Early phase:
-fever, myalgias, headaches, n/v, abdominal pain, diarrhea, cough, photophobia, tender muscles, conjunctival suffusion
Late phase Weils disease:
jaundice
acute hemorrhage, thrombocytopenia
Diagnosis:
-Agglutination test
leptospirosis
treat with doxycycline
gram negative*** pleomorphic rod
aerobic
grows on chocolate agar (factor X and factor V)
nasopharynx of adults and children
respiratory droplet transmission
Clinical:
Meningitis in children (not seen much anymore)
Epiglottitis - high fever, drooling, dysphagia, resp distress with stridor, sore throat, very rapid course, lateral neck film for diagnosis, thumbs sign
(make sure to distinguish from croup which has a steeple sign)
Pneumonia
bronchitis
acute sinusitis
haemophilus influenzae
treat with 3rd generation cephalosporin for meningitis
vaccinations
gram positive bacillus- club shaped
grows on throat and pharynx
non spore forming
transmission- bacterium or phage via respiratory droplets
sore throat, malaise
thick tonsillar exudate (grayish membrane that is tightly adherent and bleeds on attempted removal)
cervical adenopathy (Bull neck) stridor extension of membrane can lead to airway obstruction myocarditis
Corynebacterium diptheria
treat with erythromycin
antitoxin
vaccination
weakly gram negative
pleomorphic rod
facultative intracellular
grows on charcoal yeast extract (requires cysteine and iron)
grows in water/air conditioning systems
no human to human transmission
smokers, age >55, alcohol intake are risk factors
clinical
legionaires disease:
fever, malaise, cough, chills, headaches, chest pain, diarrhea, mental confusion, low pulse?
myalgias, severe headaches, and diarrhea distinguish it from other penumonias
pontiac fever:
fever, sore throat, myalgia, headache
lasts only 3 days
diagnosis with urine test!
legionella pneumophila
treatment:
fluoroquinolones, macrolide–> azithromycin, erythromycin,
(drugs for atypical pneumonia)
drugs must penetrate human cells
smallest free living bacteria
no cell wall
unaffected by cell wall inhibiting antimicrobials such as Beta lactams
sterol containing membrane
atypical pneumonia (dorms, miltary barracks)
highest incidence b/w 5-20 years old
long incuation (2-3 weeks)
fevers, malaise, headaches, cough
cough usually non productive
walking pneumonia
bullous myringitis - blood filled tympanic membrane
positive cold agglutinins** - positive in 65 % of cases
Treatment: macrolides, erythromycin, azithromycin, clarithromycin
-tetracyclines
mycoplasma pneumonia
gram positive dipplococcus- lancet shape
closes on blood agar
lysed by bile
optochin sensitive
faculattive anaerobe
most common cause of CAP
polysaccharide capsule
risk factors- influenza infection, CHF, COPD, asplenia, alcoholism
usually aspirated from the upper respiratory tract
Typical pneumonia:
- shaking chills, high fever, rigors, lobar consolidations, blood tinged (rusty) sputum
- Adult meningitis- most common cause in adults
- otitis media and sinusitis- most common cause in children
strep pneumonia
gram positive cocci in clusters catalase positive small yellow colonies on blood agar beta hemolytic ferments mannitol
reservoir - nasal flora in 25% of population
transmission- hands, sneezing, surgical wounds, picnic food
over 50 virulence factors
toxin mediated diseases:
toxic shock-TSST-1 superantigen, fever, hypotension, involvement of 3 or more organ systems
food poisoning- enterotoxin A-E, 2-6 hrs after eating, self-limited
scalded skin syndrome- exfoliative toxin A and B
Clinical:
imetigo, folliculitis, furuncle, abscess, cellulitis, mastitis, wound infections
bacteremia
endocarditis- roth spots, oslers nodes, janeway lesions, petechiae
pericarditis,
osteomyelitis
septic arthritis
Salmon colored sputum **
staph aureus
Nafcillin/oxacillin- if patient has non resistant staph infection
Vancomycin for MRSA
fungus obligate extracellular parasite seen on silver stain** Cup and saucer opportunistic in patients with HIV with CD4 count
pneumocystis jirovecii
dimorphic fungus
facultative intracellular parasite
found in RES cells
found in soil, caves, abandoned buildings with bird and bat guano
endemic to Mississippi and Ohio river valleys
Transmission:
disruption of soil, attics, bridges, barns, tearing down old structures, spelunking
Clinical:
acute pulmonary- acute pneumonia, patchy lobar or multilobar infiltrate
Chronic pulmonary- progressive often fatal, looks like TB (multiple cavities, fibrosis)
histoplasma capsulatum
fungus
broad based budding yeast
associated with soil and decaying
in areas where there are rivers and lakes
endemic to north central, south central, great lakes, etc.
acute pulmonary:
- fever, malaise, non productive cough
- lobar , multilobar or nodular infilatres, skin lesions
chronic:
cavitary lesions, fibrosis
mass like effect on CXR
blastomyces dermatitidis
southwest deserts areas
fungus
transmitted through arthroconidia - which form spherules
most are asymptomatic
pulmonary infection–> 5-21 days after exposure
-fever, weight loss, fatigue, dry cough, pleuritic chest pain
arthralgias
erythema nodosum***
CXR - with pulmonary infiltrates, hilar adenopathy
perineumonic effusion
dissemination infection
- Hiv patients
- 3rd trimester prego women
doesn’t get better with antibiotics
Coccidiodes immitis
endemic in warm climates worldwide
exposed skin is how you get infected
after larvae penetrate skin they go to pulmonary vasculature –> rupture into alveolar spaces –> swallowed in the GI tract
eggs hatch in the lumen of the small intestine
manifestations:
can be severe in immunocompromised
resembles ARDS with acute onset of dyspnea and productive cough and hemoptysis
strongyloides stercoralis
