Module 9.11 Part B

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Nonsporeforming (largely Gram-negative) anaerobes and Mycoplasma :

Nonsporeforming (largely Gram-negative) anaerobes and Mycoplasma Module 9.11 Part B



Percy the porker:

Percy the porker

Percy the porker:

Percy the porker Percy joined large finisher barn when 10 weeks old Starting coughing 10 days later, and for the rest of his life His group had below expectations weight gain, FCE (5%) over life Developed pneumonic pasteurellosis at 12 weeks, treated with penicillin Lungs collected at slaughter

Percy has enzootic pneumonia of swine = Mycoplasma hyopneumoniae:

Percy has enzootic pneumonia of swine = Mycoplasma hyopneumoniae

M. hyopneumoniae: Enzootic pneumonia of pigs:

M. hyopneumoniae: Enzootic pneumonia of pigs Chronic anteroventral bronchopneumonia of pigs, common Persists months Predisposes to secondary bacterial infections Mostly spread direct contact Acquired from sow, spread in weaner-grower pigs

M. hyopneumoniae: Enzootic pneumonia of pigs:

M. hyopneumoniae: Enzootic pneumonia of pigs Adheres ciliated epithelium AV bronchi, bronchioles Mitogenic activity produces hyperplasia BALT (“cuffing pneumonia”) Infection ciliated epithelium persists months Impairs bacterial clearance, predisposes to bacterial infections

M. hyopneumoniae: Enzootic pneumonia of pigs:

M. hyopneumoniae: Enzootic pneumonia of pigs Control by SPF herds, monitoring at slaughter or serologically, herd biosecurity Alternatively, immunization Alternatively, deal with secondary bacterial infections


Mycoplasma Smallest free-living bacteria Lack cell wall; dependent on host for nutrients Environmental survival poor Infection by close contact of animals Diseases mostly localized (respiratory tract ++++, genital tract +, conjunctiva +, udder+, sometimes septicemia)


Mycoplasma 0.3 µ m diameter Don’t stain Gram Small genome Host dependence - host species specific Obligate parasites moist mucosal surfaces Identified antigenically

Mycoplasma: Laboratory identification:

Mycoplasma : Laboratory identification Specialized laboratories Grow 2-5 + days on serum-rich media as 0.1- 1 mm colonies Subculture and identified antigenically (PCR) Antibody sometimes used

Mycoplasma: Habitat:

Mycoplasma : Habitat Moist mucosal surfaces, species specific Not too complex microflora Nasopharynx, prepuce, cervix, urethra, conjunctiva +++ Infected, diseased tissue eg lung ++ Mammary gland +


Mycoplasma Mycoplasma 85+ species Pathogens and commensals Ureaplasma 5 species Pathogens and commensals Acholeplasma Commensals

Typical Mycoplasma disease:

Typical Mycoplasma disease Mild, chronic, persistent Localized respiratory tract infections ++ Diseases of intensified livestock (close contact with carriers; also because poor environmental survival) Extracellular pathogens Important predisposition to “secondary bacterial infections”

How do Mycoplasma cause disease?:

How do Mycoplasma cause disease? Associate, colonize Ciliary or epithelial attachment (epithelial very tight contact) Evade, multiply Antigenic mimicry by absorbing host cell antigens. Persist by antigenic variation cell surface Damage Direct contact cell peroxidation , complement/antibody lysis ; Indirect : Superantigenic immunomodulation

Typical Mycoplasma diseases involve::

Typical Mycoplasma diseases involve: Septicemias (polyserositis, polyarthritis) Pneumonias Genital, urinary tract infections Mastitis Conjunctivitis Infection of red blood cells (“ Haemoplasma ”)

General features Mycoplasma control:

General features Mycoplasma control Eradication and biosecurity Vaccination in some cases Antimicrobial drugs often disappointing (tetracyclines, macrolides; fluoroquinolones better?)

“4 quadrant approach to antimicrobial selection”:

“4 quadrant approach to antimicrobial selection” Gram-positive Gram-negative Aerobe Aerobe Anaerobe Anaerobe

Mycoplasma of swine:

Mycoplasma of swine M. hyopneumoniae Enzootic pneumonia M. hyorhinis Polyserositis M. hyosynoviae Polyarthritis M. suis Anaemia

Mycoplasma of birds:

Mycoplasma of birds M. gallisepticum Chronic respiratory disease, CRD M. synoviae Infectious synovitis M. meleagridis Air sacculitis , bone deformities, decreased hatch turkeys

Mycoplasma of cattle:

Mycoplasma of cattle M. mycoides subsp. mycoides SC Contagious bovine pleuropneumonia ( exotic, reportable ) M. bovis Pneumonia, arthritis, mastitis Ureaplasma diversum Granular vulvovaginitis M. bovoculi Conjunctivitis ( Moraxella bovis predispose?) M. bovigenitalium Commensal M. canadense, M. californicum, etc Sporadic mastitis

Mycoplasma bovis:

Mycoplasma bovis Habitat URT + genital tract + udder Bronchopneumonia, 50% + lungs in cattle with feedlot pneumonia (“BRDC”) Increasingly important in recent years Mastitis: Highly infectious in large herds, gland fibrosis, purulent plugs Arthritis (concurrent with pneumonia, mastitis)

Mycoplasma of cats:

Mycoplasma of cats M. felis Mild respiratory infection? M. haemofelis (“Haemobartonella felis”) Feline infectious anaemia , usually only clinical in FLV or FIV infected cats. Spread fleas or fighting. M. haemominutum Usually subclinical M. gateae Subcutaneous abscesses (bites?)


Haemoplasma Volokhov, 2011)

Mycoplasma felis of horses:

Mycoplasma felis of horses Associated mild lower airway disease? Cause of pleural effusion, often following transport Predisposes to secondary S. zooepidemicus , then anaerobe colonization of effusion

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