Micro - respiratory infections Flashcards
Morphology of strep pneumo?
Lancet-shaped diplococci or short chains
How is strep pneumo spread?
Contact
What are some major risk factors for strep pneumo?
Asplenia is big, and the other typical ones
What are the major virulence factors of strep pneumo?
LPS capsule
Pneumolysin - pore formation
Is strep pneumo necrotizing or non-necrotizing?
Non
What is the OP and IP treatment of strep pneumo?
OP: macrolide + doxy
IP: penicillins, or macrolide + B-lactam
Otitis media from strep pneumo treatment?
amoxicillin
What are the two vaccines for strep pneumo?
Pneumovac: cargo-based, short-acting
Prevnar: protein conjugate
How is yersinia pestis spread?
Flea bites
Y pestis morphology?
Safety pins
Y pestis virulence factors
Type III secretion system injects effectors that stop phagocytosis
F1 capsule - basis of rapid tests
How can Y pestis be definitely diagnosed?
F1 capsule serology
What is the treatment for Y pestis?
Streptomycin; doxy for pneumoic because it’s contagious
Is Y pestis contagious?
Only the pneumonic form of disease
Describe the different types of plague and their unique features
Bubonic: painful LAD buboes
Septicemic: worse than bubonic, toxemia, MOF, DIC possible, etc.
Pneumonic: septicemic version disseminates to lungs; CONTAGIOUS, BLOODY AND WATERY sputum
Brucella - disease presentation
Chronic infection with granulomas in bone and liver; night sweats and long-lasting fever; back pain
Brucella phrase
Butchers in Brussels get Brucellosis from Bovines with Back Pain and Break Sweats
Brucella transmission
Raw dairy; handling animals; zoonistic in cows/sheep
Coxiella burnetti spread
aerosol and animal products
Coxiella burnetti associated disease
Q fever
Q fever S/S
Atypical pneumonia 2-4 weeks; sometimes cardiac involvement and liver.
Q fever treatment
doxycycline for coxi!
Which antivirals are NA inhibitors?
Zanamivir and oseltamivir
Which antivirals are best for flu B?
Zanamivir and oseltamivir
What does the flu HA protein do?
Facilitate attachment and penetration
What does the flu NA protein do?
Destroy receptor by cleaving sialic acid from virion and cell surface
What does the flu M2 protein do?
Only in Type A; ion channel involved in uncoating
Nocardia - who is most vulnerable?
Chronic lung disease patients; also HIV/chemo; OPPORTUNISTIC
Nocardia virulence factors
Catalse and superoxide dismutase
Nocardiosis features
Acute inflammation with necrosis and abcessation
Nocardia is Necrotic and comes in through your Nose
Nocardia treatment
Cefamandole (‘nocardia needs a man’)
Nocardia habitus
Soil and water
Nocardia spread?
Inhalation, not p to p
If you ate or inhaled dirt, which pathogens could you potentially contract?
Nocardia (inhalation)
Histoplasma (regional)
Acinetobacter (Asia/Australia)
Which fungal infections are considered opportunistic?
Aspergillus, mucormycoses, pneumocysis
Which fungal infections are considered systemic?
Histo, blasto, coccidio
Histoplasma morphology
Dimorphic yeast with BUMP CONIDIA
Where is histo endemic?
MS and OH river valleys
Central America
histoplasma virulence
yeast resists macrophage destruction
What parts of the body does histo target?
‘Reticuloendothelial system’ - lymph, spleen, BM
Histoplasmosis presentation
Cough, fever, similar symptoms to TB, potential for renal failure and CNS in immunocompromised
Treatment for histoplasmosis
Azole for competent pts; Ampho B then azoles for compromised
Blasto spread
Airborne spores
Blasto morphology
“Broad-based” budding yeast snowmen
Blasto virulence
Yeast form IS susceptible to macrophages (unlike histo)
Blasto presentation
Acute pneumonia with PURULENT BROWN/bloody sputum
40% warty skin lesions (cutaneous)
Can spread to prostate
Blasto tx
Azole if competent; AmpB+maintenance azole if compromised
Coccidioides morphology
Dimorphic spherule (not yeast) that sporulates
Coccidioides transmission
sporulation/airborne
Coccidioides vulnerable pops
SW US; AAs, AIDS/immunocompromised
Coccidioides virulence info
Very infectious; bioweapon
Coccidioides disease caused
Valley fever/Coccidiomycosis
Fever, ARTHRALGIA, fatigue, rash; long-lasting fatigue
Coccidioides script
Black HIV+ man living in California
Aspergillus morphology
45 deg septate hyphae
Aspergillus spread
sporulation/airborne
Aspergillus tx
Ampho B
Zygomycetes morphology
90 deg septate hyphae
Zygomycetes buzz words exposure
Tornadoes/disasters
Zygomycetes spread
Sporulation/airborne
Zycomycetes vulnerable pops
opportunistic/ic’d
Zygomycetes tx
Ampho B
Zycomycetes distinguishing S/S
severe HA
Pneumocystic jerovici morphology
deflated soccer balls
Pneumo jerovici who’s vulnerable?
Everyone is infected by ~4; AIDS at risk; opportunistic
Pneumo jerovici virulence and dx
Can’t be cultured; part protozoan so can’t use AmpB (cholesterol)
Silver stain to see cysts is Dx
Pneumo jerovici tx
Trimethoprim-sulfamethoxazole
Coronavirus genome
Non-seg + RNA
Flu genome
Segmented - ssRNA
Coronavirus spread
P to P through airborne droplets
Coronavirus virulence factors
S: spike protein - stimulates prod of antibody so important! HE: hemagg esterase E - envelope protein M - membrane p - budding/env formation N - nucleocapsid p - encapsidation
Coronavirus diseases
Colds, croup, SARS
What are the major causes of croup?
90% viral
Paraflu, flu, adenovirus are major sources, sometimes RSV
Coronavirus cold
mild URT, ~15-30% of colds
Coronavirus croup - which virus?
HVoC-NL63
SARS S/S
High fever, flu-like, GI symptoms
Severe LRTI progressing to pneumonia; targets Typ e II pneumocytes
Eventually, severe ARDS
Chlamydia diseases
Psittacosis
Pneumonia (atypical)
Ocular and genital infections
Describe the chlamydia life cycle
Biphasic:
- Inert EB enters cell
- Becomes RB which undergoes binary fission
Chlamydria morphology
Obligate intracellular parasite dependent on cell for many substances
Chlamydia presentation of pneumonia
Mild atypical pneumonia (slow progressing) in adolescents and young adults
HA is an important finding not typical of other pneumonias
Chlamydia virulence factors
TTS; tarp; CopN…
Chlamydia Dx
IgM titer
Chlamydia often has this area of involvement along with pneumonia
Ocular!
Legionella morphology
Aerobic G- rods
facultative intracellular parasites
Which pathogens are intracellular parasites, either facultative or obligate?
Legionella (facultative)
Chlamydia (obligate)
Brucella (facultative)
Coxiella
Legionella spread
Not P to P; through water sources
Legionella mech
Replicates in alveolar macrophages; avoids phagolysosome fusion; creates ‘special vacuole’
Legionella Dx
urine test
Legionnaire’s disease S/S
Incubates 2-10 days;
HIGH fever
cough, chills
Pontiac fever S/S
Flu-like; passes in 2-5 days; incubates 36-48 hours
Mycoplasma pneumonia vulnerable pops
LITTLE KIDS 1-5
And younger > older in general
Mycoplasma CAP
5-10% of CAP
GRADUAL, insidious onset of days/weeks
Especially consider if cough of > 3 weeks
Adenovirus srpead
Inhalation of droplets from fecal-oral
Adenovirus vulnerable pops
Children, military, pools/etc for eye infections
Adenovirus virulence factors
Hexon proteins and capsid
Which adenovirus serotypes affect GI only?
40, 41
Which adenovirus serotypes cause ARD?
4, 7
Adenovirus dx
cytopathic effect on culture
Adenovirus S/S of respiratory infection
Erythema, cough, fever, sore throat
Ocular: ‘sand’ in eye, runny nose, fever, sore throat
GI: N/V/D, fever
AdV can persist for several months after acute episode!
Acinetobacter gram __
-
Acinetobacter vulnerable pops
Australians and Asians with CAP and chronic disease
Acinetobacter virulence
Low virulence; apoptosis of laryngeal epithelium via OMP 38
Acinetobacter dx
culture
Acinetobacter S/S pneumonia
Fever, other typical
chest pain
If cutaneous: orange, bumpy skin
Acinetobacter tx
MDR - use meropenem other things….
Corynebacterium morphology
chinese letters, G+
Corynebacterium virulence
Diptheria toxin:
- B subunit facilitates entry/endocytosis
- A subunit: 1 molecule can kill cell
Diphtheria dx
culture
Corynebacterium S/S
Colonizes pharynx and forms PSEUDOMEMBRANE and VERY sore throat
Can cause heart issues
Which pathogens can potentially involve cardiac damage?
diphtheria Q fever (coxiella)
Bordetella morphology/char
Fastidious G-
Bordetella transmission
Very contagious; P to P!
Bordetella virulence factors
Pertussis toxin paralyzes cilia and causes inflammation
FHA: filamentous hemagg
Pertussis phases and symptoms
3 phases
- Catarrhal (low fever, progressive cough)
- Paroxysmal (wax/wane whoop, fatigue, cyanosis, N/V)
- Convalescent (recovery, still some cough)
Pertussis vaccine
DTaP: acellular
Bacillus anthracis morphology
boxcars - the anthrax children
G+ aerobic SPOREs
Anthrax virulence
Non-antigenic capsule
AB toxin:
-B allows receptor binding
-A: two subunits - EF edema factor - swelling; LF lethal factor - disrupts cell signals
Inhalational anthrax S/S
Two phases
- Flu-like symptoms
- Hemorrhagic mediastinitis with pleural effusion
MEDIASTINAL WIDENING ON CXR
INC UP TO 6 WKS
Hantavirus genome
Segmented (-) RNA
Hantavirus spread
Aerosolized rodent waste, esp.
DEER MOUSE
‘Santa loves reindeer; Hanta loves deer (mice)’
Hantavirus virulence
HPS causes PULMONARY CAPILLARY PERMEABILITY - edema edema edema
How does the immune system contribute to hantavirus infection pulmonary syndrome?
Lymphos and macros recruited by high viral burden - provokes endothelial overactivation and edema/migration
What is the hantavirus ‘triplet’ of S/S?
Elevated HCT
Thrombocytopenia
Leukocytosis with left shift
What are the two stages of hantavirus RDS?
- Fever and myalgias, NO SIGNS OF TYP URI
2. Lots of edema, cough, low BP
Hantavirus tx
no specific, but low fluids and use pressors
Anthrax tx
Cipro or Doxy IV
RSV vulnerables
kids, daycare, premature babies, immunodeficient
RSV genome
Enveloped, nonseg (-) RNA
RSV virulence
Respiratory tract only
Two envelope proteins -
1. F protein
2. G protein
RSV dx
F protein serology
RSV S/S
Airway inflammation, necrosis, sloughing, edema, …
SEASONAL
RSV tx
palvizumab
prophylaxis for RSV
ribavirin
ALL of the syncytial viruses have this genome
Env nonseg - RNA
Actinomyces morphology
Produce hard yellow granules
Actinomyces virulence
not highly
Actinomyces manifestation areas
Pulmonary, facial, lumpy jaw, GI
Actinomycosis S/S
Chest pain w/ inspiration, phlegm, weight loss
Actinomycosis tx
Penicillin IV 4-6 wks
Rhinovirus genome
Unenv (+) RNA
Rhinovirus spread
direct contact
Rhinovirus virulence
IRES elements - selective translation of viral
Local inflammation responsible for smyptoms as opposed to virus
Lives long on surface
Rhinovirus infection symptoms/Signs
Sore throat –>rhinorrhea/congestion
HA, facial pressure possible
Normal pharynx - no erythema!
Cough and hoarseness possible
TB phase 1
droplet of nuclei inhalted
TB phase 2
7-21 days post-infection; unrestricted multiplication and macrophage migration
TB phase 3
Macrophage activation by T cells
Tuberculin + now
Caseating necrosis begins
TB phase 4
MTB grows in weak macrophages and dissemination possible
TB phase 5
Caseous liquefication - rapid growth - bronchial necrosis/rupture - everywhhherre
TB treatment
Rifampin
Isoniazid
Pyrazinamide
Ethambutol/strepto
Francisella morpho
G- non-sporing cocco
Francisella S/S
Patchy infiltrates on CXR!!
Ulceroglandular most common -
Fever, chills, HA, exhaustion
SKIN ULCER at bite site
Francisella spread
rabbits; fleat bites; dead animals; NOT p to p
Francisella tx
streptomycin
