Mycoplasma
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Mycoplasma

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Mycoplasma infections continue to be a prominent cause of Respiratory and Genital infections effective, diagnosis and prompt treatment reduces the morbidity.

Mycoplasma infections continue to be a prominent cause of Respiratory and Genital infections effective, diagnosis and prompt treatment reduces the morbidity.

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    Mycoplasma Mycoplasma Presentation Transcript

    • MYCOPLASMA infections Dr.T.V.Rao MD
    • Edmond Nocard and Emile Roux (1898)
    • Nocard and Roux contributed for Mycoplasma discovery In 1896 Nocard and Roux reported the  cultivation of the causative agent of contagious bovine pleuropneumonia (CBPP), which was at that time a grave and widespread disease in cattle herds. The work of Nocard and Roux represented the first isolation of a mycoplasma species.
    • History The name Mycoplasma, from the Greek  mykes (fungus) and plasma (formed), was proposed in the 1950s, replacing the term pleuro pneumonia-like organisms (PPLO) referring to organisms similar to the causative agent of CBPP. It was later found that the fungus-like growth pattern of M. mycoides is unique to that species.
    • Mycoplasma Mycoplasma  species are the smallest free-living organisms. These organisms are unique among prokaryotes in that they lack a cell wall.
    • Overview of Mycoplasma Infections Mycoplasma species are the smallest free-  living organisms and are unique among prokaryotes in that they lack a cell wall. This feature is largely responsible for their biologic properties, including lack of a Gram stain reaction and nonsusceptibility to many commonly prescribed antimicrobial agents, including beta- lactams. Mycoplasma organisms are usually associated with mucosa.
    • Can part of Normal flora They reside extracellularly in the  respiratory and urogenital tracts and rarely penetrate the sub mucosa, except in the case of immunosuppression or instrumentation, when they may invade the bloodstream and disseminate to numerous organs and tissues.
    • Important Human Mycoplasma infecting Human Family – Mycoplasmataceae – requiring  cholesterol or other sterols as an essential grwoth factor. a. Genus Mycoplasma which utilize glucose or arginine but donot split urea. b. Genus Ureaplasma – which hydrolyze urea
    • Basic Characters of Mycoplasma Prokaryotic microbes  Size of 150-250 nm  Lack of a cell wall  Sterol-containing cell  membrane Fastidious growth  requirements Fried-egg or mulberry  colonies on agar
    • Mycoplasma are cell wall deficient microorganisms Cross-section of  Mycoplasma bacteria, a common cause of atypical pneumonia. This bacteria is unusual in that it lacks a cell wall.
    • Culturing Mycoplasma Mycoplasma can be  cultured on liquid or solid medium Growths optimally at 35  to 370c Medium of growth should  be enriched with 20% horse or human serum. The colonies appears as  fried egg appearance
    • Characters of Mycoplasma They are prokaryotes but lack a cell wall.  However, they have a unique cell membrane that contains sterols, which are not present in either bacteria or viruses. Mycoplasma organisms are small (150-250 nm) and have deformable membranes. The name Mycoplasma refers to the plasticity of the bacterial forms resembling fungal elements.
    • Important Species in Mycoplasma Scientists have isolated at least 17 species  of Mycoplasma from humans, 4 types of organisms are responsible for most clinically significant infections that may come to the attention of practicing physicians. These species are Mycoplasma pneumoniae, Mycoplasma hominis, Mycoplasma genitalium, and Ureaplasma species
    • How they differ from other Bacteria They have sterols in the cell membrane.   They share no DNA homology with known bacteria.  They have low guanine levels plus cytosine content.  Their genome has a low molecular weight.  They exhibit no reversion to walled forms.
    • How Mycoplasma differ from other common bacteria. However, the term mycoplasma has been  frequently used to denote any species included in the class Mollicutes). The common characteristics are the complete lack of a bacterial cell wall, osmotic fragility, colony shape and filterability through 450-nm pore diameter membrane filters. The relatively close Phylogenetic relationship of these genera was measured by comparative sequence analysis of the 5S and 16S ribosomal RNA (rRNA)
    • Specific characters of Mycoplasma However, the term mycoplasma has been frequently  used to denote any species included in the class Mollicutes). The common characteristics are the complete lack of a bacterial cell wall, osmotic fragility, colony shape and filterability through 450-nm pore diameter membrane filters. The relatively close Phylogenetic relationship of these genera was measured by comparative sequence analysis of the 5S and 16S ribosomal RNA (rRNA). The rRNA sequence analyses also revealed that the Mollicutes are not at the root of the bacterial Phylogenetic tree, but rather developed by degenerate evolution from gram-positive bacteria with a low mol% G+C (guanine plus cytosine) content of DNA,
    • How they differ from Viruses They grow on cell-  free media in vitro. They contain both  RNA and DNA. They have both  intracellular and extracellular parasitism in vivo.
    • Genomic structure is documented
    • How Race Influce Mycoplasma Infections Patients with sickle cell disease or related  hemoglobinopathies are at increased risk for severe M pneumoniae infections and may develop large pleural effusions and marked respiratory distress. Since sickle cell disease and other related hemoglobinopathies are most common among African Americans, severe complications of mycoplasmal infections also occur most frequently in this group of patients.
    • Mycoplasma found on surfaces of Mucous Membranes Mycoplasma are found most often on the  surfaces of mucous membranes. They can cause chronic inflammatory diseases of the respiratory system, urogenital tract, and joints. The most common human illnesses caused by Mycoplasma are due to infection with M. pneumoniae, which is responsible for 10-20% of all pneumonias.
    • Antigenic properties The surface antigens  are glycolipids and protiens Glycolipids are  identified by complement fixation. Proteins antigens  detected by ELISA method.
    • Resistance They are normally destroyed by heat at  450c in 15 minutes.  They are relatively resistant to pencillins, and Cephalosporins  Sensitive to Tetracyclnes, and several other antibiotics
    • Why Mycoplasma are Pathogenic The lack of a cell wall most probably facilitates  the close contact between M. pneumoniae and its host cell and guarantees the exchange of compounds, which support the growth of the bacterium. As a consequence of this bacterial surface-parasitism the host cell is severely damaged. The exchange of toxic metabolic compounds is discussed as a possible cause of cell damage, however, at this stage not a single toxic compound has been identified as a causative agent of cell damage.
    • Spread of Mycoplasma Infections The disease is world wide,  and found in all age groups, Transmission by drop let  infection of nasopharyngeal secretions. Spread is associated with  close contact of infected person Important infection in  Military personal. Even the persons  recovered from infection will harbor the pathogens for 2 moths or more
    • Clinical Manifestations Generalized aches and pains  Fever (usually 102°F)  Cough - Usually non-productive  Sore throat (nonexudative Pharyngitis)  Headache/ myalgias  Chills but not rigors  Nasal congestion with coryza  Earache  General malaise 
    • Respiratory spread Infection moves easily  among people in close contact because it is spread primarily when infected droplets from the respiratory system circulate in the air due to coughing, spitting, or sneezing
    • Pneumonia leading Manifestation in Mycoplasma infections
    • Pneumonia Pneumonia caused  by Mycoplasma is also called atypical pneumonia, walking pneumonia, or community- acquired pneumonia.
    • Mycoplasma Pneumonia Mycoplasma pneumonia is most often seen in children and young people. Up to 15 % of all cases of pneumonia in patients younger than 40 years are caused by mycoplasma pneumoniae. Most mycoplasma infections are manifested clinically as bronchitis and/or Pharyngitis. Pneumonia develops in between 3 and 10% of the patients.
    • Mycoplasma presents as non specific Respiratory infections Infections commonly  involve the oropharynx, trachea, bronchi, and lungs, usually causing unilateral pneumonia of the lower lobe. The radiographic appearance cannot be distinguished from that of other nonbacterial pneumonias.
    • Mycoplasma contributes to several Respiratory infections M pneumoniae infections lead to clinically  apparent disease involving the upper respiratory tract. In 5-10% of patients (with the rate depending on age), the infection progresses to tracheobronchitis or pneumonia and is usually self-limited. Pleural effusion (usually small) occurs in 5-20% of patients. Mycoplasmas have also been implicated in the pathogenesis of asthma, leading to acute and chronic wheezing in some individuals.
    • Radiological presentation The radiological picture is  extremely variable, but one or both lower lobes are usually involved. The opacities usually start as partly mottled, partly node-like peribronchial opacities, which may gradually develop to involve whole segments or lobes
    • Other Systemic Infections in Mycoplasma  Inrare instances other organs may be involved (central nervous system, pancreas, joints, skin, heart, and pericardium), probably as a result of haematogenous spread.
    • Mycoplasma in children In children younger than 3 years primarily  develop upper respiratory infection. M pneumoniae infection is uncommon in the first  year of life; however in neonates, it may cause severe disease. M pneumoniae infection is common in school-  aged children, with the highest rate of infection in individuals aged 5-20 years, in whom the tendency is to develop bronchitis and pneumonia.
    • Mycoplasma in New born Colonization of infants by  genital Mycoplasma species usually occurs during passage through an infected birth canal, and genital mycoplasmal organisms have been isolated from the upper respiratory tract in 15% of infants. Colonization usually does not persist beyond 2 years.
    • Cardiac Manifestations Arrhythmia and/or  ECG abnormalities (conduction defects) Congestive failure  Pericarditis  Myocarditis  Endocarditis  Dr.T.V.Rao MD 
    • Neurological Manifestations Cranial neuropathy  Aseptic meningitis or Meingoencephalitis  Transverse myelitis  Brainstem dysfunction  Dysfunction of the pyramidal or extrapyramidal tract  Cerebellar dysfunction  Cerebral infarction  Guillain-Barré syndrome  Peripheral neuropathy  Dr.T.V.Rao MD
    • Musculoskeletal Manifestations  Polyarthralgias  Acute arthritis (monoarticular or migratory)  Digital necrosis Dr.T.V.Rao MD
    • Ureaplasma species
    • Important species in Ureaplasma The Ureaplasma genus now is subdivided  into 2 species: U urealyticum and U parvum. For clinical purposes, separating infections caused by the different 2 species is not possible or necessary. In both the clinical setting and in the diagnostic laboratory, they are considered Ureaplasma species.
    • Ureaplasma differs from Mycoplasma The Ureaplasma are the  only non fermentative mollicutes i.e., they do not ferment the growth substrates such as carbohydrates and amino acids like other mollicutes but they depend on the hydrolysis of urea for their energy
    • Urease test differentiates Mycoplasma from Ureaplasma species
    • UREAPLASMA UREALYTICUM Some strains of Mycoplasma frequently isolated  from Urogenital tract of human beings and animals They are also called T strains or T form  mycoplasma They are peculiar to hydrolyze urea, which is  essential grwoth factor in addition to Cholesterol At present the have been reclassified as  Ureaplasma urealyticum.
    • Ureaplasma can be a Normal flora in sexually active individuals U. urealyticum is part of the normal genital flora  of both men and women. It is found in about 70% of sexually active humans. It had also been described to be associated with  a number of diseases in humans, including non-specific urethritis (NSU), infertility, chorioamnionitis, stillbirth, premature birth, and, in the perinatal period, pneumonia, bronchopulmonary displasia[1] and meningitis.
    • Spread of Ureaplasma Infections Major infections are  produced by M.hominis and M.urealyticum Commonly spread by Sexaul contact
    • Ureaplasma can be opportunistic pathogen in pregnancy Ureaplasma urealyticum, a common  commensals of the urogenital tract of sexually mature humans, is gaining recognition as an important opportunistic pathogen during pregnancy. While its etiologic significance in many aspects of adverse pregnancy remains controversial, recent evidence indicates that U. urealyticum in the absence of other organisms is a cause of chorioamnionitis.
    • Ureaplasma can produce several disseminated complications Evidence indicates that U. urealyticum is a  cause of septicaemia, meningitis, and pneumonia in newborn infants, particularly those born prematurely. There is strong but not definitive evidence that Ureaplasma infection of the lower respiratory tract can lead to development of chronic lung disease in very low- birth-weight infants. Although risk factors for colonization of the lower genitourinary tract have been identified,
    • Ureaplasma species: causes Urethritis  Pyelonephritis  Pelvic inflammatory disease  Endometritis or chorioamnionitis  Infectious arthritis  Surgical wound infections  Neonatal pneumonia  Neonatal meningitis  Dr.T.V.Rao MD
    • Mycoplasma and sterility Mycoplasma species do not cause vaginitis, but  they may proliferate in patients with bacterial vaginosis and may contribute to the condition. M hominis has been isolated from the endometria and fallopian tubes of approximately 10% of women with salphingits; M genitalium may also be involved in pelvic inflammatory disease and Cervicitis. Whether Ureaplasma infection causes involuntary infertility remains speculative.
    • Mycoplasma in HIV infections Mycoplasmas tend to  cause more severe infections in the HIV infected persons and cause prolonged infections. Other Immunosupressed  patients are susceptible to Mycoplasma infections
    • Diagnosis in Immunosupressed a priority The correct  microbiological diagnosis takes on greater importance in patients who are Immunosuppressed and at greater risk for disseminated infection and a poor outcome. Dr.T.V.Rao MD
    • DIAGNOSIS Mycoplasma infections
    • Majority of cases are Diagnosed with Serological Tests
    • Cold Agglutination Test Cold Agglutination  test is associated with macroglobulin antibodies that agglutinate human o RBC at low temperature
    • Cold Agglutination test procedure The serial dilutions of patients  serum are mixed with an equal volume of 0.2% washed human O group erythrocytes at low temperature The clumping is observed at  40c overnight. However the clumping is  dissociated at 370c A titer of 1:32 or > is  suggestive. A raised titer in paired serum  sample is more suggestive of infection.
    • RBC showing non agglutinating and agglutinating RBC
    • Streptococcal MG test The test is performed  by mixing serial dilutions of patients serum with heat killed suspension of Streptococcus MG. The sample is  incubated at 370c The agglutination titer  of 1:20 or > is suggestive.
    • Other Serological Tests Immunofluorescence  Hemagglutination  inhibition test Complement fixation  test less sensitivie.
    • Growth of Bacteriological Medium For isolation swabs from  throat or respiratory secretions inoculated not Mycoplasma medium The growth is slow and  takes 1 – 3 weeks The colonies appear as  fried egg, with central opaque granular area surrounded by flat translucent peripheral zone
    • Mycoplasma on PPLO agar
    • Typical Mycoplasma colonies on enriched medium The colonies showing  typical fried egg appearance. The colonies appear 2-6  days of incubation. The size of the colonies  can be from 10 – 600 microns in size. Dr.T.V.Rao MD
    • Colony characters of Mycoplasma isolates
    • M. pneumoniae colonies demonostrated in Dienes method The colonies can be  demonostrated by Dienes method. In which a block of agar  containing the colony is cut and placed on a slide, covered with a cover slip on which has been dried in alcoholic solution of methylene blue and azure.
    • Biochemical Characters of Mycoplasma The metabolism of  Mycoplasma are fermentative Most species utilize  glucose or arginine Urea is hydrolyzed by  Ureaplasma only
    • Diagnosis of Urogenital Infections Material from urethra, cervical, or vaginal  or centrifuged deposit of urine is added to separate vials with liquid mycoplasmal medium containing phenol red and 0.1% glucose, arginine or urea  The Ureaplasmal urease also breaks down urea to ammonia
    • Newer methods in Diagnosis Phylogeny based  rapid identification of urogenital Mycoplasmas and ureaplasmas based on amplification of part of 165rRNA gene by PCR is available Dr.T.V.Rao MD
    • Emerging trends in PCR primers Now several DNA  primers specific for several Mycoplasmas are available and useful for specific identification of species
    • Advantages of PCR methods  PCR methods are proving to be rapid, sensitive, and specific
    • Drugs used in Mycoplasma infections Erythromycin (M. pneumoniae and  Ureaplasma spp.)  Tetracyclnes.  Clindamycin (M. hominis)  Levofloxacin  Doxycycline  Gentamycin
    • Created for benefit of Medical and Paramedical students in Devloping world Dr.T.V.Rao MD Email doctortvrao@gmail.com