Gram (-) bacilli (Zoonotics) Flashcards
Brucella
lab tests
Bruce Farms
gram (-) bacilli
Facultative intracellular (can live inside or outside of host cells). Most of the bacteria are found in phagocytic cells like macrophages.
Urease (+)
H2S (+)
Requires CO2 to grow
Large amounts of catalase an superoxide dismutase (SOD) to protect from respiratory bursts (against H2O2 and superoxide)
Brucella
signs and symptoms
Bruce Farms
Infected macrophages.
Fever, chills, and anorexia initially.
Undulant fever (rises and falls like a wave).
Enlargement of spleen, liver, and lymph nodes (Brucella travels through multiple endothelial organs).
Osteomyelitis from chronic infection.
Brucella
Source
Bruce Farms
Farm animal’s are the reservoir.
1) Directly: from cows, pigs, or goats.
Veterinarians, slaughterhouse workers, ranchers.
2) Indirectly: contact with milk or cheese products that are unpasteurized.
Brucella
treatment
Bruce Farms
a tetracycline like doxycycline
along with rifampin for primary tx
Francisella Tularensis (Tularemia)
lab tests
Francis the rabbit
radish shaped gram (-) coccobacilli
Facultative intracellular (can live inside or outside of host cells). Cell mediated immunity needed to kill it.
DOES NOT induce respiratory bursts.
cysteine glucose blood agar
Francisella Tularensis (Tularemia)
signs and symptoms
Francis the rabbit
Causes painful ulcer.
Enters through ulcer → into macrophages → into lymph system → to reticulendothelial** organs** → causes caseation necrosis
(caseation: diseased tissue forms firm, dry, mass with cheese like appearance like in TB)
Regional lymphadenopathy (swollen lymph nodes)
Francisella Tularensis (Tularemia)
Source
Francis the rabbit
Tick vector (dermacenter tick) or Rabit vector.
Can be aerosolized and used for bioterrorism.
Francisella Tularensis (Tularemia)
treatment
Francis the rabbit
A aminoglycoside like streptomycin
Coxiella burnetii
lab tests
Curly Q the Ram
gram (-) bacilli
Obligate intracellular
Coxiella burnetii
signs and symptoms
Curly Q the Ram
DOES NOT cause a rash (vs. rickettsia or borrelia)
Q fever
* Pneumonia and headache
* Causes hepatitis
Hemmorrhage on fingers
Coxiella burnetii
Source
Curly Q the Ram
Spore like structure that comes in animal droppings and dirt.
Gets into humans though aerosol transmission, outbreaks from farm animals to farmers, or placental excretions.
Coxiella burnetii
treatment
Curly Q the Ram
Antibiotics are NOT needed, self limiting.
(Pasterurozation of milk can help prevent)
Pastuerella multocidida
lab tests
Louis Pasteur’s Lab(rador!)
gram (-) bacilli
catalase (+)
oxidase (+)
Grown on 5% sheeps blood agar
Bipolar / safety pin staining (similar to Yersinia)
Capsule
Pastuerella multocidida
VF
Louis Pasteur’s Lab(rador!)
Capsule is an important VF
Pastuerella multocidida
signs and symptoms
Louis Pasteur’s Lab(rador!)
Cellulitis after a bite.
(found in respiratory tract of small mammals like dogs and cats)
May lead to necrotizing fasciitis or osteomyelitis.
Lymphadenopathy in pt with COPD or Liver disease.
(P. multocidida is more common in cats and P. canis more common in dogs, but both can harbor the P. multocidida strain)
Pastuerella multocidida
treatment
Louis Pasteur’s Lab(rador!)
Penicillin
or
Beta lactamase inhibitor to help prevent resistance
(amoxicillin and clavulanic acid)
Bartonella henselae
lab tests
Bart the Leopard
gram (-) bacilli
Wartharin starry silver stain needed to visualize it.
Bartonella henselae
Source
Bart the Leopard
Transmitted by cat scratches
“Cat scratch fever!”
Bartonella henselae
signs and symptoms
Bart the Leopard
Can involve regional lymph nodes in axilla in one arm
(in immunocompetent)
Raised red vascular lesions in Bacillary angiomatosis
(in immunocompromised)
Bartonella henselae
ddx Bacillary angiomatosis
vs
Karposi’s sarcoma
Bart the Leopard
* Karposi’s sarcoma looks very similar to Bacillary angiomatosis
ddx using Wartharin starry silver stain (+ stain if Bacillary angiomatosis)
or ddx with biopsy (acute neutrophilic inflammation for Bacillary angiomatosis vs. lymphoplasmocytic inflammation for Karposi’s sarcome)
Bartonella henselae
treatment
Bart the Leopard
Doxycycline for Bacillary angiomatosis
Macrolides (azithromycin) for both the swelling and pain of lymph nodes and for Bacillary angiomatosis
