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Characteristics of Neisseria and Moraxella

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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 flattened Frequently appear as intracellular gram-negative diplococci within polymorphonuclear neutrophils Neisseria 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 agar Neisseria 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 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

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

8 Pathogenic Species Neisseria gonorrhoeae Neisseria meningitidis Moraxella catarrhalis

9 Saprophytic Species Neisseria lactamica, N. polysaccharea, N. cinera, N. flavescens, N. subflava, N. sicca, and N. mucosa

10 Neisseria and Related Organisms
Virulence factors Neisseria and Related Organisms N. gonorrhoeae - ↑infectivity ↓severity (fortunately) Capsule (???): attachment & anti-phagocytosis Fimbriae/pili: specific attachment to urogenital columnar epithelial cells Lipopolysaccharide (endotoxin) = tumor necrosis factor Cell wall proteins I, II, and III (interfere with phagocytosis) IgA protease (cleaves IgA on mucosal surfaces) N. meningitidis Capsule Lipopolysaccharide (endotoxin)

11 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%)

12 Neisseria: Natural Habitats
Neisseria meningitidis can colonize anogenital mucous membranes of homosexual men Saprophytic 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 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)

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 discharge in Men - White, yellow, or green pus from the penis with pain, Burning sensations during urination that may be severe, Swollen or painful testicles Symptoms 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 bronchitis Causes 10-15% of episodes of otitis media and sinusitis Rarely 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. meningitidis Nutritive base of MTM is chocolate agar Antibiotics 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 flora Nystatin: Inhibits yeast flora Trimethoprim: Inhibits swarming Proteus

27 Neisseria gonorrhoeae: Identification
Off-white colonies on chocolate agar with no discoloration of agar Acid from glucose but not maltose, sucrose, fructose, or lactose Positive superoxol test (Catalase with 30% H2O2) Colistin resistance (growth on Modified Thayer-Martin medium)

28 Neisseria and Related Organisms
N. gonorrhoeae

29 Neisseria meningitidis: Identification
Gray colonies on chocolate agar with green haze in agar immediately under and adjacent to colonies Acid from glucose and maltose but not sucrose, fructose, or lactose Colistin 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 agar No acid from glucose, maltose, sucrose, fructose, or lactose (asaccharolytic) Produces DNase Possesses the enzyme butyrate esterase

32 Neisseria and Related Organisms
M. catarrhalis

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 positive Culture isolation and biochemical identification for urogential specimens with gonorrhea refractory to treatment or sexual abuse, and non-urogenital specimens Molecular strain typing for isolates of N. gonorrhoeae in sexual abuse cases

35 Antimicrobial Therapy
Neisseria and Related Organisms Antimicrobial Therapy Was 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) test These 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 recommended Penicillin is still the drug of choice for treatment of infections caused by N. meningitidis Most 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

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