Neisseria

1. Neisseria Chapter 30 “Don’t eat chocolate agar!”

2. 2 important species: Neisseria gonorrhoeae Neisseria meningitidis Gram -, diplococci Figure 30-1 Virulence factors – Table 30-1 Neisseria

3. Primary site of infection Males – urethra (Fig. 30-2) Purulent discharge, dysuria, 2-5 day incubation 95% of men show symptoms Females – cervix Can progress to PID in 10-20% of women Vaginal discharge, dysuria, abdominal pain Only ~50% of women show symptoms Boxes 30-2 and 30-4 Gonorrhea

4. Disseminated Gonococcal Infection • In a few persons, the organism gains access to the blood stream and spreads throughout the body. This serious complication is characterized by elevated temp., joint pain, multiple small abscesses in the skin, and sometimes infections of the joints, tendons, heart valves, and meninges • Fig 30-3

5. Other N. gonorrhoeae Syndromes • Purulent conjunctivitis, particularly in newborns infected during vaginal delivery (ophthalmia neonatorum—Fig 30-4)

6. Meningitis • Site of infection • Meninges • Symptoms • Headache • Fever • Confused/Disoriented/Agitated • May lead to neurologic damage, hearing problems, and arthritis

7. Meningococcemia • Site of infection • Blood stream • Symptoms • Thrombosis of small blood vessels • Multiple organ involvement • Small skin lesions (Fig 30-5) • Shock as a result of disseminated intravascular coagulation with destruction of adrenal glands

8. Epidemiology of Gonococci • Gonorrhea occurs only in humans; there is no other reservoir • Major reservoir is asymptomatically infected person • Second to chlamydia as most commonly reported STD in US • Rates in males and females are equal • Highest in southeastern US

9. Epidemiology cont. • Occurs most often between ages of 15-24 • Decreased between ’75-’98 but has leveled out since then; 310,000 new cases were reported in 2004 • It is believed by officials that an accurate measure would double this number

10. Epidemiology cont. • Women have a 50% chance of becoming infected per single exposure • As many as half of infected women are asymptomatic • Men have approximately 20% chance of becoming infected • Most men (95%) are symptomatic

11. Epidemiology of Meningococci • Endemic throughout the world • Epidemics commonly occur in developing countries as a result of introducing a new virulent strain • Transmitted by respiratory droplets among people in prolonged close contact • Carriage is typically transient • Humans are only natural carriers

12. Other Facts About Meningococcal • Total of 1254 cases of meningococcal disease were reported in the US in 2004 • Most were meningitis • Mortality approaches 100% without treatment, but is less than 10% in patients who quickly receive appropriate antibiotic treatment

13. Laboratory Diagnosis-Gonorrhea • Gram stain is effective in men with purulent discharge • Not quite as effective in asymptomatic men • Difficult to use as proof of infection in women; depends on the skills of the microscopist • Must be proven by culture

14. Laboratory Diagnosis-Meningitis • Easily seen by stain of cerebrospinal fluid (Fig 30-6) • Unlike most bacteremia, meningococcal bacteremia has enough cells in the blood to identify

15. Treatment Prevention and Control • Penicillin is no longer used for Gonorrhea due to resistance • Beta-lactamase—plasmid transfer of genes • Mutations in penicillin-binding proteins and cell wall permeability • Ciprofloxacin resistance is common in Asia, the Pacific Islands, California, and in the male homosexual population in some US cities

16. Treatment Prevention and Control • N. meningitidis is susceptible to penicillin

17. Vaccine For Gonorrhea? • Multiple infections are still common • Variability in POR proteins, LOS, and Pili antigens make it difficult to create a vaccine • There is antigenic diversity among strains • Protection for infants against eye infections • 1% silver nitrate, 1% tetracycline, or .5% erythromycin