MYCOPLASMA to pass through bacterial membrane filters

MYCOPLASMA

INTRODUCTION

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?  Mycoplasma coming under the class
Mollicutes.There are  9 genera in the
class Mollicutes. Thus  class Mollicutes
have  3 families are Mycoplasmataceae,
Acholeplasmataceae,Anaeroplasamataceae . From that 9 genera , 5 are  veterinary importance (Mycoplasma, Ureaplasma,
Acholeplasma,Anaerplasma,Asteroplasma) .There are  100 spp in the Mycoplasma genus  .First Mycoplasma identified in 1890 was Mycoplasma
mycoides subsp mycoides .Similar types of Mycoplasmas were subsequently identified  called as Pleuro Pneumonia Like
Organisms (PPLO)

?  Generally Mycoplasma are Prokaryotes
, have capable of replication. Pleomorphic organisms which will appear as  spherical , filaments .They do not have cell
wall so they  cannot synthesizes peptidoglycan
.However  they have 3 
layered flexible  outer membrane
which will causes the flexibility property of that organism . Flexibility : Allows to pass through bacterial
membrane filters (0.22 to 0.45µ) .Sensitive to heat , dessication, detergents but they resistant to penicillin

HABITAT: –

Found on
mucosal surfaces of conjunctiva ,nasal cavity,oro-pharynx ,intestinal, genital tract . these are extracellular organisms.Generally host specific in nature

PATHOGENESIS: –

Parasitic
mycoplasms tend to adhere firmly  to host
‘ s mucous membrane (adhesin) . There they produce haemolysins, proteases, nucleases,
other lethal factors  that leads to  death of cells. Some mycoplasmal organisms  have predilection site in mesenchymal cells –
joints, serous cavities. Respiratory
tract and lungs –  frequent site of the
pathogenic organisms . It destroys  the cilia of respiratory
tract thereby causes  2° bacterial
invasion .Latency 
can occur in that microbial pathogenecity .Stress , intercurrent infection & age
predisposes the disease .Infections may be chronic or low grade and
they are exogenous or endogenous

LABORATORY DIAGNOSIS: –

Specimens
:

?  Samples are fragile in nature  , it should be  kept at refrigerated  condition and delivered to a laboratory within
24 – 48 hours of collection .Samples :Mucosal
scrapings, tracheal exudates,  aspirates,
pneumonic tissue from the edge of lesionCavity or joint fluids, mastitis milk

Isolation : –

Culture
media: Mycoplasma are fastidious organisms, facultative anaerobes,  5-10% CO?. It requires enriched media for
growth  .Basic medium is a good
quality beef infusion with supplements pH 
of the medium – 7.2 to 7.8. Commercially available agar or broth
(supplemented with horse serum 20% and yeast extract with amino acid).Penicillin
– inhibition of gram +ve Thallous acetate- inhibition of gram –ve , fungi. Specimen
should be inoculated into 2 broths and onto (2 agar plates 1 for mycoplasm,1
for urea plasm).Fluid material (fetal fluids , exudates)- directly inoculated
into broth and agar mediumSome specimens (semen, joint fluids, tissues) contain
inhibitors of mycoplasmsBoth undiluted specimen & ten fold dilutions in
mycoplasmal broth should be cultured

IDENTIFICATION: –

Differentiation  from bacterial L forms :

?  Bacteria  temporarily failed to form cell walls (L
forms) can produce microcolonies similar to the mycoplasms . Staining microcolonies with Diene ‘s
stain – aids in differentiation between L and mycoplasmal colonies .Mycoplasmal colonies retain stain L
form decolorise within 15 mins

COLONIAL MORPHOLOGY: –

Microscopically
:

?  Fried egg colonies

?  Diene ‘s stain – recognizes
microcolonies

?  Inoculated agar plates placed in a
humid atm. at 37°C

?  umbonate micro colonies when illuminated obliquely

?  Microcolonies – fried egg
appearance

IDENTIFICATION OF THE GENUS: –

Sensitivity
to digitonin :

?  Mycoplasma and urea plasma are
sensitive to digitonin

?  Done by digitonin disc applied on
the agar media

?  Positive – Zone of inhibition should
be 5 mm or more

IDENTIFICATION OF SPECIES: –

Fluorescent
antibody staining:

?  To identify M.dispar and Urea plasm
– bronchial epithelium of calves

FA (direct
and indirect) for staining mycoplasmal colonies :

q  For 
recognizing mixed cultures

q  commonly used in avian mycoplasms

?  Enzyme linked immunoperoxidase:

?  Porcine bronchial epithelium –
M.hyopneumoniae

?  AGID- Using known antisera   to detect mycoplasmal ag

?  ELISA – ag identification with known
antisera

?  Species specific DNA probes are available

?  Biochemical tests

?     glucose fermentation ,arginine
hydrolysis ,phosphatase activity

SEROLOGICAL
TEST

 

 

Antibiotics
susceptibility:

?  Although it develop resistant to
antimicrobial drugs

?  So ABST not usually performed

?  Tylosin, tetracyclin, tiamulin,
fluroquinolones used for treatment

?  Specific pathogen free (SPF )
programmes

?  Established for poultry and pig
herds

?  2 phases in these programmes :

?  Detection of infections and culling
or isolation of affected animals

?  Followed by serological monitoring
of the flocks to demonstrate continued freedom from infection

 

 

 

CBPP

?  CHARACTERISTIC STANCE – Head,
neck,extended and elbow abducted

Post
mortem lesions :

?  Lungs – marbled appearance

?  Grey ,red consolidated lobules
alternate irregularly with pink emphysematous lobules

?  Chronic : fibrinous encapsulation of necrotic foci
(viable mycoplasms)

?  Break down of capsules is major factor in the persistence
and spread of CBPP

?  Joints – fibrin in synovial space
& articular cartilage erosion

CCPP: –

?  Highly contagious

?  incubation  period : 6-10 days 

?  Transmission :

?  Direct contact

?  Carrier animal may exist

?  PM lesions :

?  Granular lung appearance

Fibrinous
pneumonia

 

CRD: –

?  Highly versatile and successful
pathogen

?  Once infected, it remains for life

?  Transmission :

?  Vertical transmission

?  Economically  significant disease

?  PM lesions:

?  sinusitis,conjunctivitis, tracheitis
with excessive mucous , air sacculitis , pneumonia , synovitis, osteomyelitis