Mycoplasma

Question 1

Mycoplasma cell characteristics

Answer 1

Do not have a cell wall
Pleomorphic
Susceptible to drying
Not susceptible to penicillin

Question 2

Mycoplasma general characteristics

Answer 2

Belong to the class Molicutes (bacteria with "soft skin")
Smallest free living bacteria

Question 3

Preferred habitat of Mycoplasma

Answer 3

Inhabit mucous membranes (obligate parasites) of respiratory and reproductive tracts
Affinity for ciliated epithelium

Question 4

Diagnosis of Mycoplasma infections

Answer 4

Fastidious - difficult to isolate in the lab
Need serum-rich media
Colonies are not visible to the “naked eye”
Mycoplasma colonies have a “fried egg” appearance

Question 5

How Mycoplasma cause disease

Answer 5

Associate, colonize = ciliary or epithelial attachment
Evade, multiply = antigenic mimicry by absorbing host cell antigens; persist by antigenic variation cell surface
Damage = direct contact cell peroxidation, complement/antibody lysis; indirect contact superantigenic immunomodulation

Question 6

Mycoplasma disease facts

Answer 6

Septicemias lead to polyserositis, polyarthritis
Pneumonia
Genital, urinary tract infections, mastitis
Conjunctivitis
Infection of red blood cells (“Hemoplasma”)
Antimicrobial drugs are often disappointing - Do not use cell wall active drugs

Question 7

Mycoplasma hyponeumoniae

Answer 7

Mycoplasma of swine
Enzootic pneumonia
Acquired from sow
Adheres to ciliary epithelium (alveoli, bronchi, bronchioles)
Mitogenic activity produces hyperplasia BALT (“cuffing pneumonia”)
Impairs bacterial clearance, predisposes to bacterial infections

Question 8

Mycoplasma bovis

Answer 8

Mycoplasma of cattle
Upper respiratory tract infection
Bronchopneumonia seen in cattle with feedlot pneumonia
Mastitis - highly infectious, leading to gland fibrosis, purulent plugs
Arthritis (concurrent with pneumonia, mastitis)

Question 9

Mycoplasma mastitis

Answer 9

Mycoplasma bovis
Drop in milk production
Milk becomes thick and intermixed with watery and purulent secretions
Udder can be swollen and the four quarters can be affected - fibrosis

Question 10

Mycoplasma mycoides subsp. mycoides

Answer 10

Contagious bovine pleuropneumonia
Most virulent Mycoplasma in cattle
Reportable disease
Foreign animal (exotic)

Question 11

Mycoplasma and urogenital infections in cattle

Answer 11

Ureaplasma and a few Mycoplasma sp. have been associated with infertility
Most are commensals in the reproductive tract
Ureaplasma diversum - can be a normal commensal organism of the lower urogenital tract

Question 12

Mycoplasma bovoculi

Answer 12

Mycoplasma of cattle

Conjunctivitis

Question 13

Mycoplasma capricolum subsp. capripneumoniae

Answer 13

Mycoplasma in goats
Contagious pleuropneumonia
Reportable disease
Fatal disease

Question 14

Mycoplasma agalactiae (an M. putrefaciens)

Answer 14

Mycoplasma in cattle

Contagious agalactia of sheep and goats

Question 15

Mycoplasma gallisepticum

Answer 15

Avian mycoplasmas
Chronic respiratory diseases in chicken and turkeys
Coughing, nasal discharges, tracheal rales, sinusitis with production of thick mucoid exudate, decrease in egg production

Question 16

Mycoplasma synoviae

Answer 16

Synovitis resulting in lameness, swelling of joints, retarded growth

Question 17

Mycoplasma felis

Answer 17

Mycoplasma of horses

Cause of pleural effusion, often following transports

Question 18

Hemotrophic Mycoplasma sp.

Answer 18

Classified by genetic relatedness
Have not been grown in vitro

Mycoplasma hemofelis
Mycoplasma hemosuis

Question 19

Mycoplasma hemofelis

Answer 19

Principal target cell = erythrocytes
Disease = Feline infectious anemia
Affects cats
Clinical signs = fever, anemia, depression, weakness, icterus
Vector is unknown

Question 20

Mycoplasma hemosuis

Answer 20

Prinicipal target cell = Erythrocytes
Affects pigs
Clinical signs = fever, anemia, weakness, icterus
Vector is unknown
Found in plasma and RBC of swine as coccoid forms with Giemsa stain

Question 21

Diagnosis of Hemotrophic Mycoplasma sp.

Answer 21

CBC, Coombs test

Microscopic detection of agent in blood smear

Question 22

Treatment of Hemotrophic Mycoplasma sp.

Answer 22

Antimicrobial therapy
Blood transfusions, corticosteroids, IV glucose
Control - test blood donors