Heme/Onc Microbiology

Gram-negative bacteria

Francisella tularensis, Yersinia pestis, Bartonella henslae, Brucella spp., Coxiella burnetii

Spirochetes

Borrelia burgdorferi, Leptospira interrogans

Obligate intracellular bacteria

Rickettsia rickettsia, Ehrilichia chaffiensis, Anaplasma phagoctophilum

DNA virus

EBV

RNA viruses

Dengue virus, Yellow Fever Virus

Apicomplexans

Plasmodium species, Babesia microti

Nematode

Wuchereria bancrofti

Enters into blood through inset bite

Francisella tularensis, Yersinia pestis, Borrelia burgdorferi, Rickettsia richettsii, Ehrlichia chaffeensis, Anaplasma phagocytophilum, Dengue virus, Plasmodium spp., Babesia microti

Enters into blood through animal contact

Francisella tularensis, Yersinia pestis, Bartonella henselae, Brucella spp., Leptospira interrogans

Lives in RBCs

Bartonella henselae, Plasmodium species, Wuchereria bancrofti

Lives in WBCs

Francisella tularensis, Brucella species, Ehrilichia chaffeensis, Anaplasma phagocytophilum, Dengue virus, EBV

Lives in lymphatics, lymph nodes

Francisella tularensis, Yersinia pestis, Bartonella henselae, Wuchereria bancrofti

Causes cancer

EBV

Requires cystine for growth (fastidious)

Francisella tularensis

Facultative intracellular in macrophages

Francisella tularensis

Rabbits

Francisella tularensis

Tick-borne

Francisella tularensis, Ehrlichia chaffeensis, Borrelia burgdorferi

Ulceroglandular tularemia MC type

Francisella tularensis

Painful, necrotic ulcer at inoculation site + regional lymphadenopathy

Francisella tularensis

Virulence involves inhibition of phagosome-lysosome fusion, causing apoptosis

Francisella tularensis

Diagnosed via serology showing ≥ 4-fold rise in IgM, IgG acute and convalescent serum

Francisella tularensis

Treat with streptomycin

Francisella tularensis

Gram-negative rod with bipolar (safety pin) staining

Yersinia pestis

Prairie dogs

Yersinia pestis

Transmission via flea bite MC

Yersinia pestis

Transmissible between human with pneumonic plague (in lungs)

Yersinia pestis

Painful lymphadenopathy (buboes) not contagious

Yersinia pestis

Septicemic plague leads to necrosis of extremities, "Black Death"

Yersinia pestis

Type III secretion system (T3SS)

Yersinia pestis

Yersinia outer proteins (Yops)

Yersinia pestis

Diagnosed via peripheral blood smear with Wright-Giemsa

Yersinia pestis

Treat with IV ciprofloxacin, levofloxacin, or moxifloxacin

Yersinia pestis

Diagnosed using Warthin-Starry silver stain

Yersinia pestis

Facultative intracellular in endothelial cells, especially in lymph nodes

Yersinia pestis

Bite, scratch, lick from infected cat

Yersinia pestis

Regional lymphadenopathy 1-3 weeks after contact

Yersinia pestis

Treat bacillary angiomatosis with erythromycin

Yersinia pestis

Zoonotic contact with sheep, goats, cattle, or pigs

Brucella species

Ingestion of unpasteurized dairy products

Brucella species, Coxiella burnetii

Fever, night sweats, & "moldy" odor of the sweat

Brucella species

Arthralgia

Brucella species

Treat with doxycycline and rifampin

Brucella species

Diagnosed with serology or blood/joint/CSF culture

Brucella species

Acute Q fever

Coxiella burnetti

Chronic Q fever (endocarditis)

Coxiella burnetti

Treat with doxycycline + hydroxychloroquine > 18 months

Coxiella burnetti

Transmitted via Ixodes tick

Borrelia burgdorferi, Anaplasma phagocytophilium, Babesia microti

Deer is normal host, humans are accidental hosts

Borrelia burgdorferi

Connecticut & Wisconsin most common locations

Borrelia burgdorferi

Tick has to be attached for 36-48 hours in order for bacteria to transmit

Borrelia burgdorferi

Causes Lyme disease

Borrelia burgdorferi

Facial nerve palsy + cardiac symptoms + multiple EMs

Borrelia burgdorferi

Chronic mono- or oligo-arthritis

Borrelia burgdorferi

Treat with doxycycline

Borrelia burgdorferi

Grows inside endothelial cells, leading to small blood vessel injury

Rickettsia rickettsii

American Dog tick, Rocky-Mountain Wood Tick most common

Rickettsia rickettsii

Endemic to AR, TN, MO, NC, & VA

Rickettsia rickettsii

Causes RMSF

Rickettsia rickettsii

Rash that first appears on the ankles and wrists and spreads to the trunk centripitally

Rickettsia rickettsii

May cause severe vasculitis

Rickettsia rickettsii

4-fold rise in IgG titer over 2-4 weeks confirms diagnosis

Rickettsia rickettsii

Treat with doxycycline before diagnosis is confirmed

Rickettsia rickettsii, Ehrlichia chaffeensis, Anaplasma phagocytophilium

Preference for monocytes

Ehrlichia chaffeensis

Lone-star tick

Ehrlichia chaffeensis

Causes Human Monocytic Ehrilichiosis (HME)

Ehrlichia chaffeensis

Morulae inside monocytes on Wright's stain can be diagnostic

Ehrlichia chaffeensis

Whole blood PCR is preferred diagnostic

Ehrlichia chaffeensis, Anaplasma phagocytophilium

Preference for neutrophils

Anaplasma phagocytophilium

Endemic to Great Lakes

Anaplasma phagocytophilium

Morulae inside PNMs on Wright's stain can be diagnostic

Anaplasma phagocytophilium

Causes Human Granulocytic Anaplasmosis (HGA)

Anaplasma phagocytophilium

Herpesviridae

Epstein-Barr Virus

Infects B cells, binds to CD21

Epstein-Barr Virus

Human only pathogen transmitted via saliva

Epstein-Barr Virus

Causes Endemic Burkitt lymphoma in African children

Epstein-Barr Virus

"Starry sky" appearance on histology

Epstein-Barr Virus

Retroviridae

Human immunodeficiency virus

Infects CD4 T-cells via gp120 and CD4 receptor, CCR5 coreceptor

Human immunodeficiency virus

Transmission via bodily fluids

Human immunodeficiency virus

CD4 T-cell count continues to decrease until reaching a critical level at which opportunistic diseases occur

Human immunodeficiency virus

CD4 < 200

AIDS

Prophylaxis for Pneumocystis jirovecii pneumonia

TMP-SMX

Prophylaxis for Toxoplasma gondii encephalitis

TMP-SMX

Prophylaxis for Mycobacterium avium complex

Azithromycin or clarithromycin

Prophylaxis for Histoplasma capsulatum

Itraconazole

Test for p24 antigen using ELISA

Human immunodeficiency virus

Flaviviridae

Dengue virus

Causes Dengue hemorrhagic fever

Dengue hemorrhagic fever

Vector is the Aedes mosquito

Dengue virus

Most common mosquito-borne viral disease in the world

Dengue virus

High fever + retro-orbital pain + severe muscle/joint pain

Dengue Fever

Plasma leakage, thrombocytopenia, bleeding

Dengue Hemorrhagic Fever

Life-threatening complication of DHF

Dengue shock syndrome

"White islands in a sea of red" appearance of skin

Dengue virus

Use RT-PCR for RNA or NS1 antigen test 0-5 days after onset for diagnosis

Dengue virus

Use IgM/IgG >7 days after onset for diagnosis

Dengue virus

Treat with fluids & acetaminophen, hospitalization in severe cases

Dengue virus

Live attenuated vaccine containing all 4 serotypes

Dengue vaccine (Dengvaxia)

Administer to patients who have had dengue or live in endemic areas

Dengue vaccine (Dengvaxia)

Jaundice, fever, bleeding/hemorrhage, "black vomit"

Yellow Fever Virus