1 / 38

Genital Mycoplasmal Disease in the Newborn

Genital Mycoplasmal Disease in the Newborn. John Baier M.D. University of Manitoba. Characteristics of Mycoplasmas. Mycoplasmas are the smallest self replicating organisms Do not have a cell wall like other bacteria Do not Gram stain

elu
Télécharger la présentation

Genital Mycoplasmal Disease in the Newborn

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Genital Mycoplasmal Disease in the Newborn John Baier M.D. University of Manitoba

  2. Characteristics of Mycoplasmas • Mycoplasmas are the smallest self replicating organisms • Do not have a cell wall like other bacteria • Do not Gram stain • Small genome and lack enzymes needed to synthesize may compounds • Complex nutritional requirements • Require host cells and their products • Difficult to culture outside of hosts • Will not grow on routine bacteriologic media

  3. Mycoplasmas in Human Disease • Difficulties in culturing have made establishing a pathogenic role of mycoplasmas difficult • Diseases caused by mycoplasmas • acute Mycoplasma pneumoniae • often subacute or chronic • lack well defined clinical presentations

  4. Mycoplasmas in Human Disease • Diseases potentially caused by mycoplasmas • Periodontal disease Mycoplasma salivarium • Arthritis Mycoplasma arthitidis, Mycoplasma fermentans • Urethritis, cervicitis Mycoplasma hominis, Ureaplasma urealyticum • Prematurity Mycoplasma hominis, Ureaplasma urealyticum • Recurrent pregnancy loss Mycoplasma hominis, Ureaplasma urealyticum • AIDS related diseases Mycoplasma penetrans, Mycoplasma fermentans • Chronic lung disease Mycoplasma hominis, Ureaplasma urealyticum

  5. Mycoplasmas Colonizing the Genital Tract • Ureaplasma urealyticum/ Ureaplasma parvum • premature labor • pneumonia • meningitis • BPD • Mycoplasma hominis • premature labor • pneumonia • meningitis • BPD? • Mycoplasma fermentans • no known association with perinatal disease • Mycoplasma genitalium • Only detectable by PCR • no known association with perinatal disease

  6. Epidemiology of Genital Tract Mycoplasmas • Commonly found • 40-80% pregnancies colonized with Ureaplasma urealyticum • 5-50% pregnancies colonized with Mycoplasma hominis • Increased colonization with • increased number of sexual partners • earlier age of first intercourse • isolation of other STDs (Chlamydia trachomatis)

  7. Transmission of Ureaplasma urealyticum to the Newborn • Vertical transmission • 18-55% in term infants • 29-55% in preterm infants • Factors that increase chance of transmission to fetus • rupture of membranes • chorioamnionitis • vaginal delivery • Transmission rate varies with gestational age • Once acquired colonization of respiratory tract may persist for months untreated

  8. Perinatal Transmission of Ureaplasma to Newborn Klein JO 1969

  9. Consequences of Genital Mycoplasma Infections in the Newborn • Variable response to infection • self limited with no long term effects • acute pneumonia • chronic inflammatory response may lead to development of chronic lung disease

  10. Ureaplasma urealyticum as a cofactor in the development of BPD • BPD is a multifactorial disease • Uu is not THE CAUSE of BPD • Conflicting data in the literature • different culture sites/methods • single culture vs. multiple culture • tracheal aspirate vs. nasal aspirate • reliability of cultures • PCR vs. culture • different populations • not a disease of larger infants • colonization with Uu is of no significance (generally) in a otherwise healthy term infant • different frequencies of organisms causing preterm birth

  11. Ureaplasma urealyticum as a cofactor in the development of BPD • Overall, isolation of Uu from airways is associated with a 2-3 fold increase in the incidence of oxygen dependency at 28 days of age • Associated with a lesser but still significant increase in the incidence of oxygen dependency at 36 weeks PCA * LSU 1992-94 *p<0.001

  12. Mechanisms of lung injury caused by Mycoplasmas • Live and heat killed mycoplasmas induce inflammatory cytokine production in a variety of lung cell types • mononuclear cells (alveolar macrophages) • respiratory epithelium • fibroblasts • In most mycoplasmas the cytokine inducing activity is been determined to be membrane lipoproteins • slight similarity to LPS • utilize LPS receptors (toll like receptors) • The component that stimulates cytokine production has not been determined for Ureaplasma urealyticum

  13. In vitro infection with U. urealyticumpreterm monocyte cytokine release Monocytes from preterm cord blood (24 to 32 weeks) were incubated with CRPMI-10% FCS alone, U. urealyticum at 103 CCU (UU3) (low inoculum) or 106 CCU (UU6) (high inoculum), or LPS (100 ng/ml) with or without U. urealyticum for 24 h. (A) TNF- ; (B) IL-6; (C) IL-10; (D) IL-8. Results are expressed as percentages of the LPS positive control value n = 6). *, P < 0.05 versus medium control; ,P < 0.05 versus LPS.

  14. Pulmonary Inflammation and isolation of Ureaplasma urealyticum

  15. Induction of CC chemokines by M hominis and U urealyticum:Cord blood mononuclear cells

  16. Uu increases inflammatory responses in animal models • Yoder et al 2003 • Intra-amniotically infected premature baboons • Increased inflammatory cell infiltrate in Uu +ve animals compared to controls of Uu – ve animals • Predominately monocytic cells

  17. Factors determining “pathogenicity” of Genital Mycoplasmas • Gestational age • animal models suggest that immature animals develop more severe disease • clinically this is a disease of the smallest infants • reduced transfer of maternal IgG • immature immune responses • Surfactant deficiency • infants with mature lungs rarely develop problems • lack of mycoplasmacidal effects of surfactant proteins • Oxygen administration/Mechanical ventilation • synergistic effect between oxygen and infection • Maternal immune response • low antibody production in mother increases risk of disease in newborn • Genetic Factors? • Variations in cytokine or pathogen pattern recognition genes • IL-1RA (maternal) • TLR2 • Biovar or serotype does not play a role • no specific pathogenicity factor known

  18. Surfactant protein A: mediation of mycoplasmacidal activity of alveolar macrophages Hickman-Davis et al 1998

  19. Clinical Presentation • Transient colonization • Non resolving HMD/Persistent colonization • Rapid development of BPD like changes • Pneumonia • PPHN (rare) • Apnea

  20. Transient respiratory tract colonization • Incidence is not known • May constitute ~ 25% of culture positive infants • Present with mild-moderate respiratory distress • HMD or TTN • Positive culture for Uu/Mh incidental • Rapid resolution without sequelae • Culture results return after patient is extubated and relatively well • Require no treatment

  21. Non resolving HMD/Persistent colonization • Represents largest proportion of infants • Initial presentation of typical HMD • Incomplete resolution • May have multiple cultures positive • initial may be negative

  22. Infants with persistent Uu are more likely to develop BPD Baier RJ et al 2003

  23. Rapid development of BPD like changes • Initial presentation of typical HMD • does not have to be severe • Poor resolution • Development of cystic appearance by first weeks of life • can be confused with PIE • likely represents pneumonia • Worse prognosis?

  24. Ureaplasmal pneumonia • May present at birth • indistinguishable from HMD • pneumonic appearance • May present several weeks after birth • apnea • respiratory distress • may progress to chronic lung disease • No other agent is cultured

  25. Adverse CNS Outcomes in infants with Ureaplasma urealyticum * * * *p<0.02

  26. Interaction between isolation of Uu and IL-1b –511T polymorphism

  27. Diagnosis and Management of Mycoplasmal Infections

  28. Diagnosis of Genital Mycoplasma infections • Who to culture? • Routine • Infants with birth weight less than 1500 grams • mechanical ventilation • preterm labor ± ROM, chorioamnionitis • Suspect genital mycoplasmas • early BPD like changes • non resolution of HMD • culture negative pneumonia

  29. Diagnosis of Genital Mycoplasma infections • What to culture? • Tracheal aspirate • Blood ? • Little predictive value of positive cultures from nose, throat, rectum, gastric aspirate • Value of repeated cultures? • Persistent positive cultures correlate better with development of BPD • frequently initial culture at birth may be negative • 3x during first week if intubated

  30. Diagnosis of Genital Mycoplasmas • Culture methods • Mycoplasmas are not hardy organisms • fresh specimens • specialized transport media • frozen • blood • CSF • frequently there are natural inhibitors to growth • serial dilutions • multiple media • cultures are difficult to interpret • require microscopic examination of colony formation • color change in media may be from other organisms

  31. Diagnosis of Genital Mycoplasmas • Polymerase Chain Reaction (PCR) • Ureaplasma • Urease gene • Multiple banded antigen • distinguishes between U. urelyticum and U. parvum • Mycoplasma hominis • 16S rRNA gene PCR for Ureaplasma based on Urease gene

  32. PCR vs Culture • PCR • rapid results <24 hours • biovar information • very sensitive • relevance of detecting ~ 10 organisms • Culture • may take longer than a week for positive ID • no biovar information • false negatives may be common depending on lab experience and specimen handling • less sensitive • detects larger numbers of viable organisms

  33. Treatment Strategies • Should you treat • Whom to treat? • What to treat with?

  34. Treatment of Genital Mycoplasmas • Treatment of genital mycoplasmas is controversial • No studies have been done to show that it alters outcome • diagnosis and treatment is often delayed • not considered • cultures take 5-7 days • distinguishing between colonization and infection • strains of Ureaplasma may be resistant to antimicrobials

  35. Treatment of Genital Mycoplasmas: Strategies • Empiric treatment of at risk infants • no studies • possible benefit of early treatment • treatment of infants who won’t develop disease with broad spectrum antibiotics • increased risk to develop yeast infections? • Treatment of culture positive or persistently positive infants • delay of treatment after much of the damage may be done • the few studies done show little or no benefit

  36. Treatment of Genital Mycoplasmas • Ureaplasma urealyticum • sensitive to macrolide antibiotics • erythromycin 30-40 mg/kg/day • 10-14 days (no studies) • Failure to clear organism • azithromycin • no data • 10mg/kg day 1 then 5/mg/kg/day x 6days? • insensitive to clindamycin • sensitive to chloramphenicol and tetracyclines • resistant cases or meningitis? Baier RJ et al 2003

  37. Treatment of Genital Mycoplasmas • Mycoplasma hominis • insensitive to macrolides • may be sensitive to gentamicin (not reliable) • sensitive to clindamycin • sensitive to chloramphenicol and tetracyclines • resistant cases or meningitis?

  38. Summary • Genital mycoplasmas frequently colonize and infect the respiratory tract of preterm infants • Infants may develop self limited disease from infection or may have chronic inflammation that may predispose to the development of BPD • Identification and treatment of infants with these organisms is frequently delayed or missed because of specialized culture requirements • The benefits of treating these infants have not been determined although treatment of infants with pneumonia or chronic inflammation may be warranted

More Related