Karteikarten
Bacterial Pathogenicity
Karten in diesem Stapel (36)
- 1What is the term for free-living bacteria?Saprophytes
- 2Why will free-living bacteria not cause disease?Not adapted to live in host e.g. incorrect temperature optima
- 3What is the term for bacteria that live in/on a host and spread between animalsParasitic bacteria
- 4What is a symbiotic relationship?Bacteria and host gain
- 5Give an example of a symbiotic relationshipCellulose digestion in the rumen by cellulase producing bacteria
Bacteria obtain nutrients and more energy available to host - 6What are commensal relationships?Bacteria gain but cause no harm
- 7What are commensal bacteria specific to?Host
Site - 8When can commensal bacteria become harmful?Some commensal bacteria can become facultative pathogens
For example, E.Coli is commensal in the gut but pathogenic if it enters the abdominal cavity (e.g. during gut surgery) - 9What are pathogenic bacteria?Gain by causing harm to the host
- 10What are the 2 types of pathogenic bacteria?Obligate pathogenic
Facultative pathogenic - 11What 2 types of bacteria can become facultative pathogenic?Saprophytes
Commensals - 12What causes bacteria to become facultative pathogenic?Altered host conditions
- 13What is exogenous infection?Infection from environment or other hosts
- 14What is endogenous infection?Infection results from animal's own commensal flora
- 15When can staphylococcus aureus become facultative pathogenic?Carried in nose and usually harmless (commensal)
Can cause abscesses if introduced through the skin or septicaemia if introduced into the blood system - 16When can antibiotics cause commensal flora to become pathogenic?Clostridium difficile is antibiotic resistant so will proliferate in antibiotic therapy = antibiotic induced colitis in horses and humans
- 17When can rapid nutritional change lead to commensal bacteria becoming facultative pathogenic?Proliferation of Clostridium perfringens = acute enterotoxaemias
- 18Give 5 ways in which defences may be reduced causing an increase in facultative pathogenicityExtremes of age
Malnutrition
Immunosuppressive drugs (e.g. corticosteroids suppress T cell proliferation)
Primary infection
Stress - 19Describe the pathway of shipping fever in transported calvesStress caused corticosteroid release
Inhibition of immune defence
Primary respiratory virus e.g. parainfluenza
Damaged alveolar macrophages
Susceptible to secondary bacterial infections e.g. Mannheimia haemolytica commensal
Pneumonia - 20How do alveolar macrophages reduce likelihood of facultative pathogenicity?Keep population of commensal bacteria under control
- 21What is bacterial pathogenicity?Ability of a bacterial species to cause disease e.g. Salmonella species is pathogenic
- 22What is virulence?Degree of pathogenicity associated with a particular bacterial strain
- 23What are virulence determinants?Structural and/or biochemical features that enable a bacterium to overcome or evade the host defences so it is more virulent
- 24What species of bacterium causes strangles in horses?Streptococcus equi
- 25What are the 2 types of bacterial invasion?Superficial invasion of skin/ mucous membrane epithelium
Deeper invasion of blood or lymph vessels (more virulent) - 26What are the 2 ways in which bacteria can invade a host?Digestion of host tissues
Subversion of host defences - 27Give 4 ways bacteria can avoid complement activationPrevent antibody detection through a capsule or fibrin covering
Spatial hindrance by lipopolysaccharides which are antigenic so activate MAC
Preventing MAC development
Mutation to avoid antibody recognition (existing antibodies against commensals) - 28Which species uses fibrin to prevent detection by host cells?Some species of Staphylococcus convert fibrinogen to fibrin by producing coagulase
Recognised as host tissues - 29How can fimbriae help bacteria avoid the immune response?Tight adhesion to epithelium
Prevents macrophage uptake and digestion - 30Give 3 ways in whch chemicals produced by bacteria can help avoid the non-specific immune systemRepel phagocytes or inhibit chemotaxis
Prevent phagocyte activity
Kill phagocytes - 31What is the term for chemicals that prevent leukocyte activity?Leukostatins
- 32What is the term for chemicals that kill leukocytes?Leukocides
- 33Give 5 ways in which bacteria can avoid the specific immune responseBacterial immunosuppression of T and B cells
Entering host cells by endocytosis
Inhabiting privileged sites with low immune surveillance
Antigenic mimicry
Antigenic variation - 34Give an example of a site of the body with low immune surveillanceJoints
- 35Give an example of antigenic mimicryLipopolysaccharides in gram positive bacteria can mimic host sugars
- 36What is the term for bacterial spread to new hosts?Transmission
Informationen
- Beschreibung
- Animal Disease 1 (Agents of Disease) Karteikarten am Bacterial Pathogenicity, erstellt von Florence Edwards am 26/11/2016.
- Erstellt von
- Florence Edwards
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