Presentation on theme: "Characteristics of Neisseria and Moraxella"— Presentation transcript:
1 Neisseria and Moraxella Meningitis, septicaemia, gonorrhoea, respiratory infection
2 Characteristics of Neisseria and Moraxella Gram-negative diplococci with adjacent sides flattenedFrequently appear as intracellular gram-negative diplococci within polymorphonuclear neutrophilsNeisseria gonorrhoeae fastidious showing optimal growth on enriched chocolate agar
5 Characteristics of Neisseria and Moraxella Growth of Neisseria meningitidis and Moraxella catarrhalis occurs on both sheep blood and chocolate agarNeisseria gonorrhoeae, N. meningitidis, and Moraxella catarrhalis capnophilic (optimal growth with 3-7% CO2)Neisseria meningitidis and N. gonorrhoeae closely related genetically and distantly to saprophytic species of Neisseria
6 Characteristics of Neisseria and Moraxella Neisseria meningitidis encapsulated (capsule the major virulence factor)Thirteen capsular polysaccharide serogroupsInvasive 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
7 Characteristics of Neisseria and Moraxella Moraxella rather than Branhamella accepted taxonomically as the genus designation for M. catarrhalis (family Moraxellaceae)Even though M. catarrhalis not a member of the family Neisseriaceae, morphologic and biochemical similarity to Neisseria allows clinical laboratory identification of M. catarrhalis with Neisseria species
9 Saprophytic SpeciesNeisseria lactamica, N. polysaccharea, N. cinera, N. flavescens, N. subflava, N. sicca, and N. mucosa
10 Neisseria and Related Organisms Virulence factorsNeisseria and Related OrganismsN. gonorrhoeae - ↑infectivity ↓severity (fortunately)Capsule (???): attachment & anti-phagocytosisFimbriae/pili: specific attachment to urogenital columnar epithelial cellsLipopolysaccharide (endotoxin) = tumor necrosis factorCell wall proteins I, II, and III (interfere with phagocytosis)IgA protease (cleaves IgA on mucosal surfaces)N. meningitidisCapsuleLipopolysaccharide (endotoxin)
11 Neisseria: Natural Habitats Neisseria gonorrhoeae an obligate pathogen with invasive infection of anogenital, oropharyngeal, and conjunctival mucous membranesNeisseria meningitidis normally colonizes oropharyneal and nasopharyngeal mucous membranes of humans (carrier rate of 8-20%)
12 Neisseria: Natural Habitats Neisseria meningitidis can colonize anogenital mucous membranes of homosexual menSaprophytic species are non-pathogenic (non-invasive) and normally colonize the oropharyngeal and nasopharyngeal mucous membranes of humans
13 Moraxella catarrhalis: Natural Habitats Present in the upper respiratory tract of % of healthy individuals, more commonly in children (50.8%) and elderly adults (26.5%)
14 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.
15 Neisseria meningitidis: Modes of Infection Neisseria meningitidis transmitted by inhalation of infectious air-born respiratory droplets or direct contact with infectious respiratory secretions.
16 Neisseria: Modes of Infection Neisseria meningitidis can be transmitted by sexual contact, especially orogenital or anogenital intercourse.Person-to-person transmission does not occur with saprophytic Neisseria species and infection (rare) is endogenous.
17 Moraxella catarrhalis: Modes of Infection Oropharyngeal endogenous strains spread into normally sterile regions of the tracheobronchial tree, the middle ear, and sinuses
18 Neisseria: Types of Infectious Disease N. gonorrhoeae second most common cause (after Chlamydia trachomatis) 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
19 Neisseria: Types of Infectious Disease N. gonorrhoeae causes oral and anorectal infections as a result of oral or anal intercourseN. gonorrhoeae disseminates with bacteremia and/or septic arthritis if untreatedDisseminated infection (bacteremia, pyogenic arthritis) by N. meningitidis and N. gonorrhoeae associated with deficiency in the terminal components of complement (C5-C8)
20 Preventative measures aren't taken gonococcal ophthalmia neonatorum affects the corneal epithelium causing microbial keratitis, ulceration and perforation
21 The bacteria are carried in semen and vaginal fluids and cause a discharge in men and women. in women - Bleeding during vaginal intercourse, Painful or burning sensations when urinating, Yellow or bloody vaginal dischargein Men - White, yellow, or green pus from the penis with pain, Burning sensations during urination that may be severe, Swollen or painful testiclesSymptoms of rectal infection include discharge, anal itching, and occasional painful bowel movements with fresh blood in the feces. Symptoms typically appear 2 to 5 days after infection but could appear as long as 30 days.
22 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, disseminated intravascular coagulation (DIC), and shock
23 Neisseria: Types of Infectious Disease Neisseria meningitidis associated with sexual transmission and gonococcal-like urethritis, cervicitis, salpingitis, and proctitis
24 Moraxella catarrhalis: Types of Infectious Disease Acute purulent exacerbation of chronic bronchitisCauses 10-15% of episodes of otitis media and sinusitisRarely associated with systemic infection (endocarditis, meningitits)
25 Neisseria gonorrhoeae and Neisseria meningitidis: Isolation Isolation often attempted from specimens with abundant normal flora (genital, oral, anorectal) (especially N. gonorrhoeae)Modified Thayer-Martin (MTM) agar an enriched and selective medium for pathogenic N. gonorrhoeae and N. meningitidisNutritive base of MTM is chocolate agarAntibiotics present in MTM selective for the growth of N. gonorrhoeae and N. meningitidis
26 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 floraNystatin: Inhibits yeast floraTrimethoprim: Inhibits swarming Proteus
27 Neisseria gonorrhoeae: Identification Off-white colonies on chocolate agar with no discoloration of agarAcid from glucose but not maltose, sucrose, fructose, or lactosePositive superoxol test (Catalase with 30% H2O2)Colistin resistance (growth on Modified Thayer-Martin medium)
29 Neisseria meningitidis: Identification Gray colonies on chocolate agar with green haze in agar immediately under and adjacent to coloniesAcid from glucose and maltose but not sucrose, fructose, or lactoseColistin resistance (growth on modified Thayer-Martin medium)
30 Neisseria and Related Organisms N. meningitidis
31 Moraxella catarrhalis: Identification Pink coloration of colonies on chocolate agar not apparent on blood agarNo acid from glucose, maltose, sucrose, fructose, or lactose (asaccharolytic)Produces DNasePossesses the enzyme butyrate esterase
33 Selected Biochemical Reactions for Identification of Neisseria and Moraxella catarrhalis1 Glu Mal Lac Suc DNa BE N. gon + – – – – – N. men + + – – – – N. lac – – – M. cat – – – – + + 1Glu=glucose, Mal=maltose, Lac=lactose, Suc=sucrose, DNa=DNase, BE=butyrate esterase (indoxyl butyrate substrate), N. gon=N. gonorrhoeae, N. men=N. meningitidis, N. lac=N. lactamica, M. cat=Moraxella catarrhalis 2Colistin-resistant saprophytic species of Neisseria
34 Laboratory Detection and Identification of Neisseria gonorrhoeae Direct PCR detection for urogenital specimens with culture confirmation when PCR positiveCulture isolation and biochemical identification for urogential specimens with gonorrhea refractory to treatment or sexual abuse, and non-urogenital specimensMolecular strain typing for isolates of N. gonorrhoeae in sexual abuse cases
35 Antimicrobial Therapy Neisseria and Related OrganismsAntimicrobial TherapyWas generally susceptible to penicillin in the US until 1976 when a pen-resistant strain was imported from Southeast Asia. This strain proliferated and spread within a few years. These strains are now detected using the cephalosporin (Cefinase) testThese strains are referred to as CMRNG (chromosome mediated resistant N.gonorrhoeae). Tetracycline and Spectinomycin chromosomal mediated resistance strains also occur.Ceftriaxone, a third generation cephalosporin, is recommendedPenicillin is still the drug of choice for treatment of infections caused by N. meningitidisMost M. catarrhalis strains produce beta lactamase, and are therefore pen-resistant.
36 Showing positive (left disk) and negative (right disk) reactions for Nitrocef Disks which include nitrocefin, a chromogenic cephalosporin