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The meningococcus. Nathan Keller Md. PhD . The Department of clinical microbiology and the national center for meningococci The Chaim Sheba Medical Center Tel Hashomer. Meningococcal Disease. Etiologic Agent:
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The meningococcus Nathan Keller Md. PhD. The Department of clinical microbiology and the national center for meningococci The Chaim Sheba Medical Center Tel Hashomer
Meningococcal Disease Etiologic Agent: • Neisseria meningitidis (Gram-negative diplococcus bacterium) with multiple serogroups ( A, B, C, D, 29E, H, I, K, L, W-135, X, Y, and Z). • Strains belonging to groups A, B, C, Y and W-135 are implicated most frequently in invasive disease.
Neisseria gonorrhoeae Gram negative intracellular diplococci
Neisseria meningitidis • Aerobic gram-negative bacteria • At least 13 serogroups based on characteristics of the polysaccharide capsule • Most invasive disease caused by serogroups A, B, C, Y, and W-135 • Relative importance of serogroups depends on geographic location and other factors (e.g. age)
Meningococcal meninigitis • second most common meningitis • pneumococcus, most common • fatal if untreated • responds well to antibiotic therapy • penicillin
N. meningitidis • resides in man only • usually sporadic cases • mostly young children • outbreaks • adults • crowded conditions • e.g. army barracks
Neisseriameningitidis • upper respiratory tractinfection • adhesion pili • bloodstream brain
Capsule • capsule • inhibit phagocytosis • anti-capsular antibodies • stop infection • antigenic variation • serogroups • vaccine • multiple serogroups
Identification of infectious agents in the diagnostic laboratory • Aids treatment • Helps antibiotic selection • General hospital laboratory • physiological tests • Reference laboratories • Genetic tests
Laboratory Diagnosis • spinal fluid • Gram negative diplococci • within polymorphonuclear cells • meningococcal antigens • Culture • Thayer Martin agar • Choclate agar, Blood agar
Microscopy • spinal fluids (meningitis) • sensitivity poor
Isolation and identification • Step 2. Colonies Gram stained • cells observed microscopically
Step 3.Isolated bacteria are speciated • Generally using physiological tests
Antibiotic susceptibility testing Susceptible Not susceptible Bacterial lawn Growth No growth Antibiotic disk Data on Usraeli susceptibility will be given by dr block
Neisseria meningitidesDiagnosis • Immediate • Microscopy • Antigen detection • Molecular
Meningococcemia - intracellular diplococci in buffy coat leukocytes
Neisseria meningitidesDiagnosis • Antigen detection
Antigen detection assay Kurzynski et al JCM jun 1985
Real-time PCR ds DNA Cycle one Dye Cycle two Cycle 30 2 30
DNA-DNA hybridization Strain 1 Heat + Strain 2 0% Homology 100% Homology
Cell surface of Neisseria meningitidis Capsule - polysacch. serogroup A, B, C, Y, W-135, etc. Pilus Outer membrane phospholipid Opa (opacity - protein) porin (serotype 2,15,etc.) lipooligosaccharide Peptidoglycan layer Cytoplasmic membrane Cytoplasm
Case Definition Clinical Description: Meningococcal disease manifests most commonly as meningitis and/or meningococcemia that may progress rapidly to purpura fulminans, shock, and death. However, other manifestations might be observed. Laboratory criteria for diagnosis: Isolation of Neisseria meningitidis from a normally sterile site (e.g., blood or cerebrospinal fluid (CSF) or, less commonly, joint, pleural, or pericardial fluid)
Case Definition Case Classification Probable:a case with a positive antigen test in cerebrospinal fluid or clinical purpura fulminans in the absence of a positive blood culture. What about real time PCR? Confirmed:a clinically compatible case that is laboratory confirmed.
באדיבותה של ד"ר אמיליה אניס המחלקה לאפידמיולוגיה משרד הבריאות
Laboratory confirmed isolates of Neisseria meningitidis from blood and cerebrospinal fluid 1986 - March 2005
Laboratory confirmed isolates of Neisseria meningitidis from blood and cerebrospinal fluid – 1986 - March 2005
Laboratory confirmed isolates of Neisseria meningitidis from blood and cerebrospinal fluid – 1986 - March 2005
Laboratory confirmed isolates of Neisseria meningitidis from blood and cerebrospinal fluid – 1986 - March 2005
Laboratory confirmed isolates of Neisseria meningitidis from blood and cerebrospinal fluid – 1986 - March 2005
Meningococci this year • Gr B 21 (32) • Gr Y 7 (8) • Gr W135 2 • Polyagglut 1 (1) • Gr A - (1) • Gr C - (4) • (Number of cases in 2004)
λ M11 M13 M18 M19 M20 M21 λ M23 M24 M25 M26 M28 λ בידודי חיידקי מנינגוקוקים שהתקבלו לפי מקורם: PFGE of GR B meningococci Feb-Mar 2005 λ – סמן גודל
Dice (Tol 1.0%-1.0%) (H>0.0% S>0.0%) [0.0%-100.0%] PFGE NheI No. Hospital Residence % 100 40 60 80 M20 . Hadassa ein karem Beit Shemesh M28 . Ichilov Tira M11 . Belinson Kiriat Sefer M26 . Sheba Ashdod Belinson Ramat Gan M19 . M13 Kaplan Yavne M18 Sheba Bnei Brak M25 Kaplan Ashdod M21 Volfson Holon Sheba Holon M23 Volfson Holon M24 PFGE analysis of GR B meningococci באדיבותה של ד"ר לאה ולינסקי המעבדה לביולוגיה מולקולרית מעבדות מרכזיות משרד הבריאות ירושלים
Neisseria gonorrhoeae Gram negative intracellular diplococci
תודות • ד"ר לאה ולינסקי • יהודית דוידסון • ד"ר גיל סמולן • פרידה יעקובוביץ • ד"ר גנריאטה רוזל • גיה סרקיסיאן • ד"ר בלוק • צוות המעבדה