BrucellaBrucella

Six species of Six species of BrucellaBrucella B.melitensis, B.abortus, B.suis, B.melitensis, B.abortus, B.suis,

B.canisB.canis Sir David Bruce Sir David Bruce [brucellosis][brucellosis], ,

Bernhard Bang Bernhard Bang [Bang's disease][Bang's disease] Undulant fever, Malta fever, Undulant fever, Malta fever,

Mediterranean remittent fever Mediterranean remittent fever

BrucellaBrucella

small (0.5 × 0.6 to 1.5 μm), nonmotile, small (0.5 × 0.6 to 1.5 μm), nonmotile, nonencapsulated, gram-negative nonencapsulated, gram-negative coccobacilli coccobacilli

grows slowly grows slowly strictly aerobic strictly aerobic does not ferment carbohydrates does not ferment carbohydrates

BrucellaBrucella

endotoxin is less toxic endotoxin is less toxic intracellular parasite intracellular parasite the organisms are phagocytosed by the organisms are phagocytosed by

macrophages and monocytes macrophages and monocytes phagocytosed bacteria are carried to the phagocytosed bacteria are carried to the

spleen, liver, bone marrow, lymph nodesspleen, liver, bone marrow, lymph nodes the bacteria secrete proteins that induce the bacteria secrete proteins that induce

granuloma formation granuloma formation

BrucellaBrucella

Intracellular pathogen that is resistant to Intracellular pathogen that is resistant to killing in serum and by phagocytes killing in serum and by phagocytes

Smooth colonies associated with Smooth colonies associated with virulence virulence

goats and sheep goats and sheep (Brucella melitensis)(Brucella melitensis) cattle cattle (Brucella abortus)(Brucella abortus) swine (Brucella suis)swine (Brucella suis) dogs, foxes (Brucella canis)dogs, foxes (Brucella canis)

BrucellaBrucella

Latin America, Africa, the Mediterranean Latin America, Africa, the Mediterranean basin, the Middle East, and Western Asia basin, the Middle East, and Western Asia

More than 500,000 documented cases More than 500,000 documented cases Vaccination of animals Vaccination of animals Direct contact with the organism (e.g., a Direct contact with the organism (e.g., a

laboratory exposure), ingestion (e.g., laboratory exposure), ingestion (e.g., consumption of contaminated food consumption of contaminated food products), or inhalation products), or inhalation

BrucellaBrucella

BrucellaBrucella causes mild or asymptomatic causes mild or asymptomatic disease in the natural host disease in the natural host

Erythritol (breast, uterus, placenta)Erythritol (breast, uterus, placenta) Brucellae are shed in high numbers in Brucellae are shed in high numbers in

milk, urine, and birth products milk, urine, and birth products B.melitensisB.melitensis is the most common spp is the most common spp

BrucellaBrucella-Clinical diseases-Clinical diseases

Brucellosis:Brucellosis: Initial nonspecific Initial nonspecific symptoms of malaise, chills, sweats, symptoms of malaise, chills, sweats, fatigue, myalgias, weight loss, fatigue, myalgias, weight loss, arthralgias, and fever; can be intermittent arthralgias, and fever; can be intermittent (undulant fever)(undulant fever)

can progress to systemic involvement can progress to systemic involvement (gastrointestinal tract, bones or joints, (gastrointestinal tract, bones or joints, respiratory tract, other organs) respiratory tract, other organs)

BrucellaBrucella-Clinical diseases-Clinical diseases

Incubation period 1-6 weeksIncubation period 1-6 weeks Fever rises in the afternoonFever rises in the afternoon Falling at night by drenching sweatFalling at night by drenching sweat Lymph nodes enlarge, SMLymph nodes enlarge, SM Hepatitis, steomyelitisHepatitis, steomyelitis Generalized infection subsides usuallyGeneralized infection subsides usually A chronic state may occurA chronic state may occur

BrucellaBrucella-Diagnosis-Diagnosis

grow slowly grow slowly most enriched blood agars most enriched blood agars microscopic and colonial morphology microscopic and colonial morphology positive oxidase and urease reactions positive oxidase and urease reactions B. abortusB. abortus and and B. melitensis, B. abortus,B. melitensis, B. abortus,

and and B. suisB. suis will react with antisera will react with antisera prepared against prepared against B. abortusB. abortus or or B. B. melitensismelitensis

Brucella-SerologyBrucella-Serology

IgM, IgG, IgAIgM, IgG, IgA Four fold increase or 1/80 indicate active Four fold increase or 1/80 indicate active

infection infection If agglutination negative “blocking If agglutination negative “blocking

antibodies” add antihumanglobulinantibodies” add antihumanglobulin

BrucellaBrucella-Treatment-Treatment

Doxycycline+rifampinDoxycycline+rifampin Trimethoprim-sulfamethoxazole for Trimethoprim-sulfamethoxazole for

pregnant women and for children pregnant women and for children younger than 8 years younger than 8 years

6 weeks or longer 6 weeks or longer Fluoroquinolones, macrolides, penicillins, Fluoroquinolones, macrolides, penicillins,

and cephalosporins either ineffective or and cephalosporins either ineffective or have unpredictable activity. have unpredictable activity.

FrancisellaFrancisella

Two species, Two species, Francisella tularensisFrancisella tularensis and and Francisella philomiragiaFrancisella philomiragia

the causative agent of the causative agent of tularemiatularemia (also (also called called glandular fever, rabbit fever, tick glandular fever, rabbit fever, tick fever,fever, and and deer fly feverdeer fly fever) in animals and ) in animals and humans humans

very small (0.2 × 0.2 to 0.7 μm), faintly very small (0.2 × 0.2 to 0.7 μm), faintly staining, gram-negative coccobacillus staining, gram-negative coccobacillus

nonmotile nonmotile thin lipid capsule thin lipid capsule fastidious requirements (most strains fastidious requirements (most strains

require cysteine for growth)require cysteine for growth) strictly aerobic and requires 3 or more strictly aerobic and requires 3 or more

days days

Gram stain of Gram stain of Francisella tularensisFrancisella tularensis isolated in culture; note the extremely small coccobacilli isolated in culture; note the extremely small coccobacilli

Antiphagocytic capsule Antiphagocytic capsule Intracellular pathogen resistant to killing in Intracellular pathogen resistant to killing in

serum and by phagocytes serum and by phagocytes Wild mammals, domestic animals, birds, fish, Wild mammals, domestic animals, birds, fish,

and blood-sucking arthropods are reservoirs; and blood-sucking arthropods are reservoirs; rabbits and hard ticks are most common hosts; rabbits and hard ticks are most common hosts; humans are accidental hosts humans are accidental hosts

Worldwide distribution Worldwide distribution The infectious dose is very small The infectious dose is very small

Human tularemia is acquired most often from Human tularemia is acquired most often from the bite of an infected "hard-shell" tick (e.g., the bite of an infected "hard-shell" tick (e.g., Ixodes, Dermacentor, AmbylommaIxodes, Dermacentor, Ambylomma spp.) spp.)

or from contact with an infected animal or or from contact with an infected animal or domestic pet domestic pet

F. tularensisF. tularensis requires as few as 10 organisms requires as few as 10 organisms when exposure is by an arthropod bite when exposure is by an arthropod bite

Ulceroglandular tularemia:Ulceroglandular tularemia: Painful papule develops Painful papule develops at the site of inoculation that progresses to ulceration; at the site of inoculation that progresses to ulceration; localized lymphadenopathy localized lymphadenopathy

Oculoglandular tularemia:Oculoglandular tularemia: Following inoculation into Following inoculation into the eye (e.g., rubbing eye with a contaminated finger), the eye (e.g., rubbing eye with a contaminated finger), painful conjunctivitis develops with regional painful conjunctivitis develops with regional lymphadenopathy lymphadenopathy

Pneumonic tularemia:Pneumonic tularemia: Pneumonitis with signs of Pneumonitis with signs of sepsis develops rapidly after exposure to contaminated sepsis develops rapidly after exposure to contaminated aerosols; high mortality unless promptly diagnosed and aerosols; high mortality unless promptly diagnosed and treated treated

Ulceroglandular tularemia is the most common Ulceroglandular tularemia is the most common manifestation manifestation

FrancisellaFrancisella-Diagnosis-Diagnosis

F. tularensisF. tularensis are hazardous for both the physician and are hazardous for both the physician and the laboratory worker the laboratory worker

Microscopy is insensitive due yo small size and faintly Microscopy is insensitive due yo small size and faintly stainingstaining

Fluorescein-labeled antibodiesFluorescein-labeled antibodies PCRPCR F. tularensisF. tularensis can grow on chocolate agar or buffered can grow on chocolate agar or buffered

charcoal yeast extract (BCYE) agar, media charcoal yeast extract (BCYE) agar, media supplemented with cysteine supplemented with cysteine

a fourfold or greater increase in the titer of antibodies a fourfold or greater increase in the titer of antibodies during the illness or a single titer of 1:160 or greater during the illness or a single titer of 1:160 or greater