The document discusses Neisseria, a genus of Gram-negative cocci that includes the human pathogens N. gonorrhoeae and N. meningitidis. N. gonorrhoeae causes the sexually transmitted infection gonorrhea, while N. meningitidis most commonly causes meningitis. The document provides details on the clinical presentation, diagnosis, treatment and prevention of infections caused by these Neisseria species.

1. GRAM NEGATIVE COCCI Dr Kamran Afzal Classified Microbiologist

2. Family Neisseriaceae Gram-negative cocci Residents of mucous membranes Genera include Neisseria, Moraxella, Acinetobacter 2 primary human pathogens Neisseria gonorrhoeae Neisseria meningitidis Both are Gram-negative intracellular diplococci

3. Family: Neisseriaceae Genus: Neisseria

4. Genus Neisseria Gram-negative, bean-shaped, diplococci No flagella or spores Virulence factors Capsules Pili, other surface molecules for attachment; slows phagocytosis IgA protease – cleaves secretory IgG Strict parasites, do not survive long outside of the host Aerobic or microaerophilic Oxidative metabolism Produce catalase and cytochrome oxidase Pathogenic species require enriched complex media and CO 2

5. Neisseria gonorrhoeae Causes gonorrhea, an STD Virulence factors: pili, other surface molecules, IgA protease Strictly a human infection In top 5 STDs Does not survive more than 1-2 hours on fomites Infection is asymptomatic in 10% of males and 50% of females

6. Gonorrhea Males – urethritis, yellowish discharge, scarring and infertility Females – vaginitis, urethritis, salpingitis (PID), common cause of sterility and ectopic tubal pregnancies Extragenital infections – anal, pharygeal, conjunctivitis, septicemia, arthritis

7. Potential for PID Potential scar tissue blockage - infertility

8. Gonorrhea in newborns Infected as they pass through birth canal Eye inflammation, blindness Prevented by prophylaxis after birth

9. Diagnosis and Control Gram stain Gram-negative intracellular (neutrophils) diplococci from urethral, vaginal, cervical, or eye exudate – presumptive identification Culture 20-30% of new cases are penicillinase-producing PPNG or tetracycline resistant TRNG Combined therapies indicated Recurrent infections can occur Reportable infectious disease

10. Treatment GC - used to use only penicillin Resistant strains are emerging so  -lactamase testing should be done For penicillin resistant strains or penicillin sensitive individuals substitute ceftriaxone or spectinomycin (1 dose to treat GC) plus 7 days of doxycycline to treat possible coexisting C. trachomatis infection Amoxicillin or ampicillin or Penicillin G plus probenecid can be used for uncomplicated cases

11. Neisseria meningitidis Morphology Capsulated Gram negative diplococci 0.5 – 1 µm K idney shaped, flat sides adjacent Intracellular, usually Non-motile Non spore-forming

12. Virulence factors ANTIGENS Capsular polysaccharide 13 serogroups (A, B, C, D, W135, X, Y, Z, H, K & L) Used in vaccine Serogroups A, B, C, Y, W135 account for about 90% of all infections OMP 5 classes Serogroups further subdivided into 20 serotypes PILI

13. TOXIN ENDOTOXIN Lipid A part of lipopolysaccharide Causes fever and shock ENZYME IgA Protease

14. Epidemiology Reservoir and Habitat Upper respiratory tract of humans Transmission Direct contact and air borne droplets Close contact with infectious person (e.g., family members, day care centers, military barracks, prisons, and other institutional settings) Incubation period: 1-7 days Carriage 5-30% of normal persons may harbor meningococci in nasopharynx

15. Common cause of meningitis between the ages of 2-18 years Highest incidence in children 2-5 years of age Group A meningococci 90% of outbreaks Group C Africa, Asia and South America Group W135 Occasionally

16. Diseases - N. meningitidis Meningitis Meningococcemia Septicemia with or without meningitis Meningoencephalitis Pneumonia Bacteremia Arthritis Urethritis

17. Meningitis

18. Definition Inflammation of the membranes of the brain or spinal cord

19. Etiology Infectious

20. Non-infectious

21. Etiology according to Patient Age Age Common bacteria Birth - 1 month S. agalactiae, E. coli, K. pneumoniae, L. monocytogenes, enterococcus species 1 - 3 months S. agalactiae, E. coli, L. monocytogenes, H. influenzae, S. pneumoniae, N. meningitidis 3 months to over 15 years S. pneumoniae, N. meningitidis, H. influenzae

22. Neisseria meningitidis Spread of bacteria from a nasopharyngeal infection to blood and CSF

23. Pathogenesis

24. Clinical features Symptoms IN ADULTS

25. IN BABIES

26. Neck and back stiffness Positive Kernig’s and Brudzinski’s signs In children, there is usually presence of neck rigidity with bulging fontanelle Signs

27. Complications

28. CSF – Acute Bacterial Meningitis CSF (Lumbar puncture) Cloudy or purulent Elevated pressure Increased protein Decreased glucose Cell count Usually > 1000 cells/ µL with Neutrophils predominating Gram stain Gram negative intracellular diplococci

29. CSF evaluation Positive (MTB) Negative Positive Negative Culture Increased +/- Increased Increased 5-40 Protein < 30% Normal <40% 66% CSF : plasma Glucose ratio Decreased Normal Decreased 60-80 Glucose Increased Predominate Late 5 Lymphocytes +/- increased Early Predominate 0 Polymorphs <500 <1000 >1000 0-5 Cells TB Viral Bacterial Normal

30. Laboratory diagnosis Specimens Blood and CSF for smear and culture Nasophyrangeal swab for carrier state Culture media Blood agar Chocolate agar Selective medium (Modified Thayer-Martin medium) To avoid contamination vancomycin, amphotericin B and colistin are added

31. Growth characteristics Oxygen Requirement Aerobic or facultative anaerobic Temperature 37 0 C Growth promoted by 5-10% CO 2 Colony morphology 1-2 mm dia, convex, grey, translucent, non-pigmented and non-hemolytic After 48 hours, colonies are larger with an opaque raised centre and transparent margins

32. Biochemical reactions Oxidase positive Ferments glucose and maltose but not sucrose or lactose

33. Serology Latex agglutination test Antibodies to meningococcal polysaccharides can be detected Results are available within 20 – 30 minutes

34. Antibiotic sensitivity testing Ampicillin/Penicillin Ceftriaxone Chloramphenicol Rifampicin Ciprofloxacin Meropenem

35. Treatment Empiric Antibiotics Ceftriaxone / Cefotaxime Add Vancomycin (till possibility of Penicillin-resistant Strep pneumoniae has been ruled out) Add Ampicillin (for Listeria infections) For patients with serious Penicillin allergies, Meropenem Ceftazidime + Vancomycin for neurosurgical patients Add Acyclovir in case of viral infection Definitive Therapy As per C/S report

36. Immunity and Prevention Infants - passive immunity from mothers Under 2 years of age - do not reliably produce antibodies with bacterial polysaccharides Quadrivalent menigococcal polysaccharide vaccine (A,C,Y & W135) The use of meningococcal vaccine should be strongly advised if an outbreak occurs

37. Chemoprophylaxis Antibiotics Rifampicin is the drug of choice, given for 2 days A single oral dose of Ciprofloxacin or an Inj of Ceftriaxone is also effective Indications Should be given to household members of a patient who are exposed Hospital contacts need not be treated unless intense exposure has occurred

38. Meningococcemia Septicemia and fulminant meningococcemia

39. Clinical features Intravascular multiplication of N. meningitidis Abrupt onset of spiking fevers, chills, arthralgia, joint and muscle pains Abrupt onset of hypotension and tachycardia Rapidly enlarging petechial lesions Wide spread purpura Shock DIC Coma Death ensues within hours

40. Skin Lesions of Meningococcemia NOTE: Petechiae have coalesced into hemorrhagic bullae

41. The most severe form of meningococcemia is the life threatening WATERHOUSE FRIDERICHSEN SYNDROME Septic shock Bilateral hemorrhages into the adrenal glands -> adrenal insufficiency LABORATORY FINDINGS Increased PT and PTTK Raised fibrin dimers Low fibrinogen levels Depressed platelet count Fulminant meningococcemia

42. Other Gram-negative Cocci and Coccobacilli Genus Branhamella Branhamella catarrhalis – found in nasopharynx: significant opportunist in cancer, diabetes, alcoholism Genus Moraxella Bacilli; found on mucous membranes Genus Acinetobacter Gram-negative bacilli; non-living reservoir; source of nosocomial infections

43. Clinical significance Other Neisseria species Rarely associated with endocarditis, septicemia, and meningitis B. catarrhalis - may be a significant cause of otitis media and maxillary sinusitis in children May cause pneumonia and bronchitis in immunocompromised individuals May also occasionally cause endocarditis, meningitis and septicemia

44. Metabolism Difference between Aerobic and Anaerobic (Fermentation) cellular respiration Aerobic cellular respiration -> Results in complete breakdown of glucose to carbon dioxide, water and a lot of ATP Anaerobic respiration and Fermentation -> Only partially breaks down glucose, into pyruvic acid and organic waste products and a little ATP

45. Oxidation - Reduction reactions Redox reaction A chemical reaction in which electrons are gained, lost or shared Oxidation The loss of electrons by a molecule, atom or ion Reduction The gain of electrons by a molecule, atom or ion

46. Bacterial respiration Used to denote involvement of a membrane associated electron transport chain in the process of oxidation Aerobic Final electron recipient in oxidation process is molecular oxygen Anaerobic Final electron recipient is an organic molecule in the absence of oxygen, this oxidative process is referred to as ‘Fermentation’ All bacteria in evolution were anaerobes

47. CSF analysis returns with the following values: Glucose 20, WBC 1200/µL, Protein 300. This profile is consistent with A. Fungal meningitis B. Bacterial meningitis C. Viral meningitis D. Non-infectious meningitis E. Tuberculous meningitis

48. CSF analysis returns with the following values: Glucose 20, WBC 1200/µL, Protein 300. This profile is consistent with A. Fungal meningitis B. Bacterial meningitis C. Viral meningitis D. Non-infectious meningitis E. Tuberculous meningitis

49. Which of the following is an absolute contraindication to performing an LP? A. Coagulopathy B. Infection of the overlying skin C. Thrombocytopenia D. Meningococcemia E. Malignant Hypertension

50. Which of the following is an absolute contraindication to performing an LP? A. Coagulopathy B. Infection of the overlying skin C. Thrombocytopenia D. Meningococcemia E. Malignant Hypertension

51. Which antibiotic regimen should be initiated in an immunocompromised adult patient suspected of having bacterial meningitis without any allergies A. Penicillin G & Ceftriaxone B. Ceftriaxone & Vancomycin C. Vanco, Gentamicin, & Ceftriaxone D. Ceftriaxone, Vancomycin & Acyclovir E. Ceftriaxone, Acyclovir & Amphotericin B

52. Which antibiotic regimen should be initiated in an immunocompromised adult patient suspected of having bacterial meningitis without any allergies A. Penicillin G & Ceftriaxone B. Ceftriaxone & Vancomycin C. Vanco, Gentamicin, & Ceftriaxone D. Ceftriaxone, Vancomycin & Acyclovir E. Ceftriaxone, Acyclovir & Amphotericin B