This is simplified presentation of Mycoplasma for MBBS students and also useful for those who want to know basic of mycoplasma.

1. Mycoplasma
Dr Kamlesh Patel
MBBS MD DCP
Assist Professor, Microbiology,
SAIMS Indore
Director, jaailab.com

2. General characters
• Smallest free living organisms i.e. may grow on artificial
culture medium (Versus Virus).
• Gram Negative, but better stained with Giemsa stain.
• Non- sporing, Non-flagellated.
• Non-motile, may show gliding motility.
• Nocard and Roux (1898) : Discovered and named
Pleuropnemonia like organisms or PPLO.

3. General characters
• Lack a cell wall (versus L- form; L= Lister) hence
Resistant to cell wall active antibiotics. (Streptobacillus
moniliformis)
• Pleomorphic (Coccoid/ bacilli or sometimes filamentous
also)
• Surrounded by a single triple layered membrane containing
sterol (Cholesterol), hence Need incorporation of sterol in
medium for growth.
• Reproduce by binary fission & budding.

4. Genus and species
• Two main genus causing human infections:
• Genus Mycoplasma:
• Mycoplasma pneumoniae: Pneumonia (atypical) and other respiratory
infections.
• Mycoplasma Hominis, Mycoplasma genitalum: NGU
(Nongonococcal urethritis), prostatitis and sometimes Septicemia, GU
tract infections & wound infections.
• Genus Ureaplasma:
• Ureaplasma urealyticum (urease positive): NGU, LRTI,
septicemia, meningitis.

5. Pathogenesis
• M.pneumoniae:
• Mechanisms of respiratory infection:
• Adhesion with respiratory mucosa
• Induces injury to respiratory mucosa by H2O2, Cytotoxins and
Lipoproteins.
• Spread is mainly by droplets.
• It is Common in close families & military recruits.
• Incubation period: 2- 4 weeks
• Infections:
• Upper respiratory tract infection: Pharyngitis, tracheobronchitis
• Lower respiratory tract infection: Atypical pneumonia (Interstitial pneumonia)
& bronchiolitis.
• Atypical pneumonia: Causative agents:
• M. pneumoniae,
• Legionella,
• Chlamydia,
• Viruses.

6. Pathogenesis
• M. hominis & others:
• Non-gonococcal urethritis (NGU),
• Postpartum urethritis,
• Proctitis,
• Acute salpingitis,
• PID etc.
• Transmitted by sexual contact.

7. Lab Diagnosis
• Sample:
• For respiratory infection:
• Swabs (wooden shafts not recommended as wood itself is toxic for mycoplasmas).
• Throat swabs, Nasophyrangeal swabs
• Sputum, Throat washings
• Tracheal & transtracheal aspirates, BAL
• For Genital tract specimens:
• Urethral, cervical & vaginal swabs.
• Prostatic secretions
• Semen
• Urine
• Others
• CSF, Blood, Amniotic fluid etc.
• Transport Media: Tripticase-soy broth with 0.5% bovine serum albumin and
viral transport medium can also be used.

8. Lab Diagnosis
• Culture:
• Culture medium:
• PPLO Agar solid medium.
• Methylene blue-glucose diphasic medium (solid and liquid):
• Mycoplasma glucose agar medium.
• SP4 medium
• Culture characterstrics:
• M. pneumoniae:
• On solid medium fried egg like colonies seen.
• In liquid medium we look for Change in pH.
• Result should be confirmed by hemabsorption &/or tetrazolium
reduction test or by fluorescence microscope using isothiocyanate
dye.

9. Lab Diagnosis
• Genital Mycoplasmas:
• M.hominis and U.urealyticum are easily cultiviable, growth within 1-
5 days and shows Typical large colonies, Fried egg morphology.
• M.genitalum & M.fermentans grow slowly & difficult to cultivate.
• Sensitivity:
• It is not required because the organisms usually sensitive to
Doxycyclin and other antibiotics.

10. Lab Diagnosis
• Serology:
• Antigen capture assay.
• Complement fixation test.
• Detection of IgM and IgG antibodies to Mycoplasma.
• Direct immunoflorescence assay (by using isothiocynate
dye)
• Molecular diagnosis:
• PCR.
• LAMPs.

11. Thanks