Mollicutes

Question 1

Mollicutes

Answer 1

Myycoplasmas or minimal cells
Small genome and small colony size
Physiologically restricted and highly fastidious
Lack cell walls (no peptidoglycan)
Sterols present in cell membrane

Question 2

Mollicute genera

Answer 2

Mycoplasma~ 100 species of pathogens and commensals

Question 3

Ureaplasma

Answer 3

Pathogens and commensals

Question 4

Spiroplasma

Answer 4

Plant pathogens, insect commensals

Question 5

Anaeroplasma

Answer 5

Rumen commensal

Question 6

Acholeplasma

Answer 6

Mainly commensal

Question 7

Pathogenicity

Answer 7

“Parasites” of animals, arthropods, and plants
Tends to be mucosal-associated
Most commonly asymptomatic > chronic> sub- acute > acute
High inter-strain heterogeneity
Pathogenic and non-pathogenic strains can be very similar
Lack conventional virulence factors

Majority of ones that are known cause respiratory issues, and not that many cases of death

Question 8

Diagnosis of mycoplasmosis

Answer 8

Typically use multiple tests

Pathology- gross and histo
Isolation and identification- phenotypic, biochemical, antigenic, genomic 
Serological response
Antigenic detection
Genomic detection

Problems with asymptomatic carriage, strain heterogeneity, and genetic similarity between pathogenic and non strains

Question 9

Virulence mechanisms of mollicutes

Answer 9

Adhesions
Physical disruption- Competition for metabolites and degradative enzymes 
Cytotoxic metabolites
Endotoxicity- lipogalactan and lipopeptides
Antigenic variation/capsules
Intrapagoctic survival
Assimilation of host cell antigens 
Autoimmunity
Lymphocyte suppression
Superantigenicity
Antigen persistence 

Immunomodulation and immunopathology

Question 10

Respiratory mycoplasma infection

Answer 10

Mycoplasma hponeumoniae/Porcine Enzootic Pneumonia

Inhalation -> adherence to ciliated epithelium -> colonization of bronchioles/alveoli -> ciliostasis and ciliotoxicity -> immunomodulation/immune evasion -> alveolar and peribronchial inflammation ->mononuclear cell infiltration and hyperplasia -> lymph node enlargement ->catarrhal exudation -> consolidation

Frequent chronic infection that persists months/years with 2o consequences. Not typically life threatening, more of a production loss disease

Question 11

2o consequences of Mycoplasma hyponeumoniae

Answer 11

Pasteurella multocida
Actinobacillus pleuropneumoniae
Haemophilus parasuis
Bordetella bronchiseptica 
Streptococcus suis

Can me a major health concern

Question 12

Contagious pleuropneumonia

Answer 12

Acute/peracute respiratory mycoplasmosis

Includes contagious bovine pleuropneumonia and contagious caprine pleuropneumonia

Notifiable diseases
occasionally sub-acute/chronic 
High mortality
Highly contagious
Remission and re-activation
Chronic carriers
Neutrophil infiltration ->necrosis
Fluid exudation
Vascular inflammation 

Not a problem in UK, but still notifiable. Mainly a problem in sub tropics and sometimes S. Europe

Question 13

M. myciodes

Answer 13

Causes contagious bovine pleuropneumonia

Question 14

M. capricolum

Answer 14

Causes contagious Caprine pleuropneumonia

Question 15

Erythrocyte associated mycoplasmas

Answer 15

Feline anemia caused by Haemobartonella felis or mycoplasma haemofelis

Porcine Eperythrozoonosis cause by Eperythrozoon suis or Mycoplasma haemosuis

Question 16

General features of haemotrophic mycoplasmas

Answer 16

Unculturable

Potentially predisposed by inter-current infection- FIA from FLV?

Detected in increasing range of mammalian host species
Emerging genus of RBC parasitic/pathogenic Mycoplasma

Question 17

Infection scheme of mycoplasma heam”x”

Answer 17

mycoplasma enters into the circulation and adheres to erythrocytes. Can lead to autoimmunity or indentations/rupture, which can lead to erythrocyte lysis and anemia

Question 18

Haemotrophic mycoplasmas and hosts

Answer 18

3 major groupings, and seem to have the ability to cross species. May be zoonotic

Question 19

Control of mycoplasmoses

Answer 19

Test and slaughter
Disease-free herds/flocks via testing
selective breeding
Antibacterial chemotherapy- protein synthesis inhibitor  such as tetracycline (cant target wall bc dont have one)
Vaccines