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NEISSERIA. Neisseria Thayer Martin Medium Oxidase test N. gonorrhoeae Gonorrhea, Ophthalmia neonatorum, Septic arthritis N. meningitidis Meningitis, Cerebral spinal Fever, Waterhouse-Friedrichsen Syndrome. Key Words. NEISSERIA. Neisseria gonorrhoeae. Neisseria : Natural Habitats.
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Neisseria Thayer Martin Medium Oxidase test N. gonorrhoeae Gonorrhea, Ophthalmia neonatorum, Septic arthritis N. meningitidis Meningitis, Cerebral spinal Fever, Waterhouse-Friedrichsen Syndrome Key Words
NEISSERIA Neisseria gonorrhoeae
Neisseria: Natural Habitats • Neisseria gonorrhoeae an obligate pathogen with invasive infection of anogenital, oropharyngeal, and conjunctival mucous membranes • Neisseria meningitidis normally colonizes oropharyneal and nasopharyngeal mucous membranes of humans (carrier rate of 8-20%)
Neisseria Gram negative Diplococci (pairs of cocci) Oxidase positive Culture Chocolate agar heated blood (brown) Thayer Martin. selective Incubation 35-36 C 5-10% CO2 essential Very delicate and autolytic
Modified Thayer-Martin Agar • Colistin: Inhibits gram-negative flora (N. gonorrhoeae and N. meningitidis resistant to colistin, most saprophyic species of Neisseria susceptible) • Vancomycin: Inhibits gram-positive flora • Nystatin: Inhibits yeast flora • Trimethoprim: Inhibits swarming Proteus
Selected Biochemical Reactions for Identification of Neisseria and Moraxella catarrhalis1 Glu Mal Lac Suc DNa N. gon + – – – – N. men + + – – – N. lac2 + + + – – M. cat– –– – + 1Glu=glucose, Mal=maltose, Lac=lactose, Suc=sucrose, DNa=DNase, N.gon=N. gonorrhoeae, N. men=N. meningitidis, N. lac=N. lactamica, M. cat=Moraxellacatarrhalis 2Colistin-resistant saprophytic species of Neisseria
Neisseria gonorrhoeae: Modes of Infection • Neisseria gonorrhoeae spread by sexual contact, including genital, anogenital, and orogenital. Spread from infected mother to neonate as ocular infection during birth. Non-sexual transmission not documented.
N. gonorrhoeae the “Gonococcus" • Found only in human • Gonorrhea - Second most common venereal disease (after chlamydia trachomatis) • N. gonorrhoeae of sexually-transmitted lower genital tract disease (acute urethritis in men, endocervicitis in women) • N. gonorrhoeae untreated can progress to epididymitis, prostatitis, urethral stricture, salpingitis, tubo-ovarian abscess, and pelvic inflammatory disease
Neisseria: Types of Infectious Disease • N. gonorrhoeae causes oral and anorectal infections as a result of oral or anal intercourse • N. gonorrhoeae disseminates with bacteremia and/or septic arthritis if untreated • Disseminated infection (bacteremia, pyogenic arthritis) by N. meningitidis and N.gonorrhoeae associated with deficiency in the terminal components of complement (C5-C8)
Smear • Polymorphonuclear cell • Gram negative cocci • many in cells
Antibiotic therapy • βlactamase-resistant cephalosporin • e.g. ceftriaxone • Resistant strains • common • produce β lactamases • destroy penicillin
Pathogensis • Adhesion to genital epithelium • outer membrane • pili • Antigenicity • highly variable among strains • No vaccine • IgA protease • also N. meningitidis
N. gonorrhoeae • Tissue injury • lipopolysaccharide • peptidoglycan
N. meningitidis • Resides in man only • Usually sporadic cases • mostly young children • Outbreaks • adults • crowded conditions • e.g. army barracks, dorms
Neisseria meningitidis: Modes of Infection • Neisseria meningitidis transmitted by inhalation of infectious air-born respiratory droplets or direct contact with infectious respiratory secretions.
Neisseriameningitidis • upper respiratory tractinfection • adhesion pili • bloodstream brain
Meningococcal meninigitis • Second most common meningitis • pneumococcus, most common • Fatal if untreated • Responds well to antibiotic therapy • penicillin
Neisseria: Types of Infectious Disease • N. meningitidis causes a rapidly progressive meningitis in school-aged children, adolescents, and young adults with a mortality of 7-13% • N. meningitidis bacteremia (mortality of 19-70%) a cause of Waterhouse-Friderichsen syndrome with petechiae, purpura, adrenal hemorrhage, dissemin-ated intravascular coagulation, and shock
Characteristics of N. meningtidis • Neisseria meningitidis encapsulated (capsule the major virulence factor) • Thirteen capsular polysaccharide serogroups • Invasive infection caused by organisms with one of five capsular serogroups (A, B, C, Y, and W135) with 90% of meningococcal disease due to serogroups A, B, and C
Capsule • Capsule • inhibit phagocytosis • Anti-capsular antibodies • stop infection • Antigenic variation • sero-groups • Vaccine • multiple sero-groups
Laboratory Diagnosis Spinal fluid Gram negative diplococci Within polymorphonuclear cells Detection of Meningococcal antigens Culture Blood /Chocolate Agar CSF – Pressure Glucose Proteins Chlorides Normal
Neisseria Meningitidis • Treatment -Penicillin - rifampicin or Minocycline- prophylaxis - Vaccine- polyvalent vaccine A,C,Y,W135
Moraxella catarrhalis: Types of Infectious Disease • Acute purulent exacerbation of chronic bronchitis • Causes 10-15% of episodes of otitis media and sinusitis • Rarely associated with systemic infection (endocarditis, meningitits)