Zoonotic infection. Causative agents of the plague, tularemia, brucellosis and anthrax. Laboratory diagnostics and prophylaxis of diseases. Vinnitsa National Pirogov Memorial Medical University / Department of microbiology

Taxonomy and classification Pathogenic Yersinia Taxonomy and classification Family: Enterobacteriaceae Genus: Yersinia Medical important species: Y.pestis Y. pseudotuberculosis Y.enterocolitica

Yersinia pestis

Cultivation It is facultative anaerobe, and can grow at wide range of pH (4-10) and temperature (2-450C) Ordinary nutrient media (MPA and MPB) Selective media with hemolyzed blood

Antigen structure and virulent factors Fraction I (F-I) antigen V and W antigens Virulent enzymes Plague toxins

Epidemiology of the plague Source of infection is wild or domestic rodents The major route of transmission: By biting of infected fleas By skinning and handling of carcasses of infected wild animals By inhalation of the dried flea feces or respiratory droplets from person with pneumonic form By drinking of polluted water

Pathogenesis of the plague Major clinical forms : Bubonic form Pneumonic form Enteric form Septicemia

Bubonic form of plague

Laboratory diagnostics Microscopy Culture method Biological method

Prevention and therapy Specific prevention: Chemoprophylaxis

Other Yersinia Y. pseudotuberculosis Feature of morphology: polymorphic gram-negative rods, motile at 220C and non-motile at 370C Features of cultivation: it grows slowly and scanty onto the solid media (MPA, MacConkey agar) with formation R or S-colony Biochemical features: it is H2S (-), urease (+) and rhamnose (+)

Epidemiology and pathogenesis The source of infection is infected rodent. Humans may be infected by ingestion of contaminated row vegetables or by drinking of contaminated water. Clinical forms of pseudotuberculosis: Fatal typhoid like illness with hepatosplenomegaly and purpura (generalized form) Mesenteric lymphadenitis simulating acute appendicitis (local form)

Y.enterocolitica Clinical forms: Self-limited gastroenteritis or enterocolitis (young children) Mesenteric adenitis and terminal ileitis (older children) Systemic disease with bacteremia, meningitidis, arthralgia or erythema nodosum (adults)

Laboratory diagnostics Culture method Serology

Francisella tularensis Taxonomy and classification: Family: Brucellaceae Genes: Francisella Species: F.tularensis Biovars : type A – tularensis (non-arctic or American type; high virulent) type B – palearctika (European and Asian type; low virulent)

Francisella tularensis

Cultivation It is obligate aerobe, nutritionally exacting and slowly growing bacteria Fransis blood agar with dextrose and cystine Yolk blood agar

Virulent factors Capsule Vi-antigen Endotoxin Allergens

Epidemiology Reservoirs: wild rodents, squirrels, hedgehogs, and rabbits (source of infection). Human may be infected by: Biting of infected ticks Direct contact with infected animal Ingestion of contaminated food or water Inhalation of infective aerosols or dried feces

Pathogenesis and immunity Clinical forms: Skin-bubonic form Anginose form Pneumonic form Enteric form Septic form

Bubonic form of tularemia

Laboratory diagnostics skin allergic test Serology. Experimental infection. Prevention : specific

Brucella Taxonomy: Family: Brucellaceae Genus: Brucella Medical important species: B. melitensis B. abortus B. suis

Morphology

Cultivation and cultural properties Brucella are strict aerobs, but B. abortus is capnophilic (it requires 5-10% of CO2 for propagation ) The media for cultivation of Brucella: Liver infusion media (broth and agar); Serum potato infusion agar Serum dextrose agar with addition of polymyxin, bacitracin and cycloheximide

Epidemiology The source of infection is infected domestic animal (cattle, goats, sheep, pigs) The human may be infected by: Ingestion Direct contact Inhalation

Pathogenesis Human infection may be three types: Latent infection; Acute or subacute brucellosis Chronic brucellosis

Enlarged lymph nodes at brucellosis

Laboratory diagnose Culture method Serology

Bacillus anthracis Taxonomy Family: Bacillaceae Genus: Bacillus Medical important species: B. anthracis

B.anthracis

Cultivation It is aerobe and facultative anaerobe and easily cultivated onto the ordinary nutrient media Nutrient media: Nutrient agar Blood agar Gelatin stab culture (“inverted fir tree”) Penicillin media (“string of pearles”)

Antigen structure and virulent factors Capsular antigen Cell wall antigen Somatic antigen Exotoxin:oedema factor (OF), protective antigen (PA) and lethal factor (LF).

Epidemiology The source of infection is ill animal (cattle, sheep, horses, and swine). Human may be infected by: Direct contact Inhalation Ingestion

Pathogenesis Cutaneous form Pulmonary anthrax Intestinal anthrax Septicemia

Cutaneous form of anthrax

Laboratory diagnostics Microscopy Culture method Experimental infection Allergic skin test Ascoli`s thermoprecipitin test

Prevention Animals and human are protected by active immunization