《微生物学》课程PPT课件讲稿（英文版）Lecture 11 Neisseriaceae

Comparison of meningococcus and gonococcus Pathobiology e Similarities. Both diplococci Share about 80% dNA Neither makes exotoxin: both make endotoxin Both are relatively good colonizers Other species colonize mucous membranes and skin and rarely cause disease BIOL 533 Lecture ll

BIOL 533 2 Lecture 11 Comparison of Meningococcus and Gonococcus • Pathobiology • Similarities: – Both diploccocci – Share about 80% DNA – Neither makes exotoxin; both make endotoxin – Both are relatively good colonizers • Other species colonize mucous membranes and skin, and rarely cause disease

Comparison of meningococcus and gonococcus Differences Gonococcus causes gonorrhea Localized inflammation(usually in urethra)and is very rarely fatal Meningococcus causes meningitis and other diseases Systemic and life-threatening disease BIOL 533 Lecture ll

BIOL 533 3 Lecture 11 Comparison of Meningococcus and Gonococcus • Differences: – Gonococcus causes gonorrhea • Localized inflammation (usually in urethra) and is very rarely fatal – Meningococcus causes meningitis and other diseases • Systemic and life-threatening disease

Comparison of meningococcus and gonococcus Why are diseases so different Presence in normal flora 10% healthy people colonized by meningococcus in posterior pharynx Gonococcus not present BIOL 533 Lecture ll

BIOL 533 4 Lecture 11 Comparison of Meningococcus and Gonococcus • Why are diseases so different? • Presence in normal flora – 10% healthy people colonized by meningococcus in posterior pharynx – Gonococcus not present

Comparison of meningococcus and gonococcus Penetration of mucous membranes Mechanism similar for the two organisms Penetrate different mucous membranes columnar epithelial cells Meningococcus---nasopharnyx Gonococcus--fallopian tubes BIOL 533 Lecture ll

BIOL 533 5 Lecture 11 Comparison of Meningococcus and Gonococcus • Penetration of mucous membranes – Mechanism similar for the two organisms – Penetrate different mucous membranes columnar epithelial cells • Meningococcus—nasopharnyx • Gonococcus—fallopian tubes

Comparison of meningococcus and gonococcus Survival against host defenses Gonococcus killed in bloodstream Meningococcus grows extremely fast in bloodstream, reaching very high blood titers Reason large capsule and outer membrane proteins BIOL 533 Lecture ll

BIOL 533 6 Lecture 11 Comparison of Meningococcus and Gonococcus • Survival against host defenses – Gonococcus killed in bloodstream – Meningococcus grows extremely fast in bloodstream, reaching very high blood titers • Reason: large capsule and outer membrane proteins

Comparison of meningococcus and gonococcus Signs and symptoms of two diseases Gonococcus(highly invasive) cause symptoms frequently but sites are localized Production of pus and pain during urination Sequellae depending on location Inflammation of fallopian tubes Pelvic inflammatory disease > May result in scarring leading to infertility and ectopic pregnancy BIOL 533 7 Lecture ll

BIOL 533 7 Lecture 11 Comparison of Meningococcus and Gonococcus • Signs and symptoms of two diseases – Gonococcus (highly invasive) cause symptoms frequently, but sites are localized • Production of pus and pain during urination • Sequellae depending on location – Inflammation of fallopian tubes – Pelvic inflammatory disease » May result in scarring, leading to infertility and ectopic pregnancy

Comparison of meningococcus and gonococcus Signs and symptoms Meningococcus(highly serum-resistant ) causes septicemia with multiple organ involvement, including cns Damage caused by Disseminated intravascular coagulation(DIC), accompanied by shock fever, and other responses Due to large amount of endotoxin in blood, tissues Due to ability of meningococcus to thrive in blood BIOL 533 Lecture ll

BIOL 533 8 Lecture 11 Comparison of Meningococcus and Gonococcus • Signs and symptoms – Meningococcus (highly serum-resistant )- causes septicemia with multiple organ involvement, including CNS – Damage caused by • Disseminated intravascular coagulation (DIC), accompanied by shock, fever, and other responses • Due to large amount of endotoxin in blood, tissues • Due to ability of meningococcus to thrive in blood

Neisseria meningitidis Morphology Encapulated gram diplococci e Colonization Asymptomatically in nasopharnyx of healthy ndividuals BIOL 533 Lecture ll

BIOL 533 9 Lecture 11 Neisseria meningitidis • Morphology – Encapulated Gram— diplococci • Colonization – Asymptomatically in nasopharnyx of healthy individuals

Neisseria meningitidis Microbial physiology and structure Colony morphology Form transparent, non-pigmented, non-hemolytic colonies on chocolate blood agar in 5% cO2 Capsule indicated by large mucoid colonies Physiology o Oxidase+ Acid production from glucose and maltose, but not sucrose or lactose Several serotypes known BIOL 533 Lecture ll

BIOL 533 10 Lecture 11 Neisseria meningitidis • Microbial physiology and structure – Colony morphology • Form transparent, non-pigmented, non-hemolytic colonies on chocolate blood agar in 5% CO2 – Capsule indicated by large mucoid colonies – Physiology • Oxidase+ • Acid production from glucose and maltose, but not sucrose or lactose • Several serotypes known

Neisseria meningitidis Causes of pathogenesis ability to colonize nasopharny nyx due to presence of pili ability to resist host defenses and spread due to presence of capsule Expression of toxic effects due to presence of endotol×in BIOL 533 Lecture ll

BIOL 533 11 Lecture 11 Neisseria meningitidis • Causes of pathogenesis – Ability to colonize nasopharnyx due to presence of pili – Ability to resist host defenses and spread due to presence of capsule – Expression of toxic effects due to presence of endotoxin