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MYCOPLASMA
II MBBS
Dr Ekta ChourasiaMicrobiology, GMCA
19/02/2008 Dr Ekta,Microbiology, GMCA
Key Words
MycoplasmaNo cell wallPleomorphismFried egg coloniesDiene’s stainPrimary atypical/
walking pneumoniaGenital infections
Cold agglutination test
Cell culture contamination
UreaplasmaHydrolysis of urea
19/02/2008 Dr Ekta,Microbiology, GMCA
MYCOPLASMASmallest (<1µ) free-living micro organisms,
lack cell wall.
1st member of this group – isolated by Nocard & Roux (1898) – caused bovine pleuropneumonia.
Later, many similar isolates were obtained from animals, human beings, plants & environmental sources – called as “pleuropneumonia like organisms”(PPLO).
19/02/2008 Dr Ekta,Microbiology, GMCA
MYCOPLASMA
1956- PPLO replaced by Mycoplasma.– Myco : fungus like branching filaments– Plasma : plasticity
highly pleomorphic – no fixed shape or size - Lack cell wall.
Can pass through bacterial filters.
19/02/2008 Dr Ekta,Microbiology, GMCA
Mycoplasmas of Humans Parasitic1. Established pathogens: M.
pneumoniae2. Presumed pathogens: M. hominis,
U. urealyticum3. Non pathogenic: M. orale, M. buccale,
M. genitalium, M. fermentans Saprophytic – present mainly on skin
& in mouth.
19/02/2008 Dr Ekta,Microbiology, GMCA
Pathogenicity Produce surface infections – adhere
to the mucosa of respiratory, gastrointestinal & genitourinary tracts with the help of adhesin.
Two types of diseases:1. Atypical Pneumonia2. Genital infections
19/02/2008 Dr Ekta,Microbiology, GMCA
Mycoplasmal pneumonia
Also called Primary Atypical Pneumonia/ Walking pneumonia
Seen in all ages Incubation period: 1-3 wksTransmission: airborne droplets of
nasopharyngeal secretions, close contacts (families, military recruits).
19/02/2008 Dr Ekta,Microbiology, GMCA
Mycoplasmal pneumoniaGradual onset with fever, malaise,
chills, headache & sore throat.
Severe cough with blood tinged sputum (worsens at night)
Complications: bullous myringitis & otitis, meningitis, encephalitis, hemolytic anemia
19/02/2008 Dr Ekta,Microbiology, GMCA
Laboratory Diagnosis
Specimens – throat swabs, respiratory secretions.
Microscopy –
1. Highly pleomorphic, varying from small spherical shapes to longer branching filaments.
2. Gram negative, but better stained with Giemsa.
19/02/2008 Dr Ekta,Microbiology, GMCA
Laboratory Diagnosis Isolation of Mycoplasma (Culture) –1. Semi solid enriched medium containing
20% horse or human serum, yeast extract & DNA. Penicillium & Thallium acetate are selective agents. (serum – source of cholesterol & other lipids)
2. Incubate aerobically for 7 -12 days with 5–10% CO2 at 35-37°C. (temp range 22- 41°C, parasites 35- 37°C, saprophytes – lower temp)
19/02/2008 Dr Ekta,Microbiology, GMCA
Laboratory Diagnosis
3. Typical “fried egg” appearance of colonies - Central opaque granular area of growth extending into the depth of the medium, surrounded by a flat, translucent peripheral zone.
4. Colonies best seen with a hand lens after staining with Diene’s method.
5. Produce beta hemolytic colonies, can agglutinate guinea pig erythrocytes.
19/02/2008 Dr Ekta,Microbiology, GMCA
Fried egg coloniesFried egg colonies
19/02/2008 Dr Ekta,Microbiology, GMCA
Identification of Isolates
Growth Inhibition Test – inhibition of growth around discs impregnated with specific antisera.
Immunofluorescence on colonies transferred to glass slides.
Serological diagnosis PCR
19/02/2008 Dr Ekta,Microbiology, GMCA
Identification of Isolates Serological diagnosis1. Specific tests – IF, HAI2. Non specific serological tests –
cold agglutination tests (Abs agglutinate human group O red cells at low temperature, 4C).
1:32 titer or above is significant.
19/02/2008 Dr Ekta,Microbiology, GMCA
Ureaplasma urealyticumStrains of mycoplasma isolated from
the urogenital tract of human beings & animals.
Form very tiny colonies - hence called T strain or T form of mycoplasmas.
Hydrolyzes urea
19/02/2008 Dr Ekta,Microbiology, GMCA
Genital InfectionsCaused by M. hominis & U. urealyticumTransmitted by sexual contactMen - Nonspecific urethritis, proctitis,
balanoposthitis & Reiter’s syndromeWomen – acute salpingitis, PID,
cervicitis, vaginitisAlso associated with infertility,
abortion, postpartum fever, chorioamnionitis & low birth weight infants
19/02/2008 Dr Ekta,Microbiology, GMCA
Mycoplasma & HIV infectionSevere & prolonged infections in HIV
infected & other immunodeficient individuals
19/02/2008 Dr Ekta,Microbiology, GMCA
Mycoplasma as cell culture contaminants
Contaminates continuous cell cultures maintained in laboratories
Interferes with the growth of viruses in these cultures.
Mistaken for viruses.
Eradication from infected cells is difficult.
19/02/2008 Dr Ekta,Microbiology, GMCA
TreatmentTetracycline, Erythromycin &
Clarithromycin – drug of choice
Resistant to antibiotics which interfere with bacterial cell wall synthesis.
Newer macrolides & quinolones being used now.