Bacteriology-39 Neisseria Meningitis Infections/bacterial Meningitis*

Front 1

Define meningitis

Back 1

An inflammation of the meninges with the exudative response present in the CSF. There are many infectious and some non-infectious causes of meningitis. The infectious agents that cause meningitis include bacteria, viruses and fungi

Front 2

What are some host conditions that predispose patients to bacterial meningitis

Back 2

Age, Immunocompromised state, Basilar skull fracture, Head trauma: postneurosurgery, Cerebrospinal fluid shunt

Front 3

What is critical to the management of bacterial meningitis

Back 3

Early recognition and institution of appropriate therapy. The disease is life-threatening and sequelae are common

Front 4

The majority of meningitis cases in the US are caused by what microorganisms

Back 4

Streptococcus pneumoniae, group B streptococci, and Neisseria meningitidis. Less than 16 years ago, Haemophilus influenzae was the most common cause in children less than 5

Front 5

What bacteria cause meningitis in those less than one month old

Back 5

group B streptococci (70%)
Listeria monocytogenes (25%)
Streptococcus pneumoniae (5%)
Also E. coli K-1, Klebsiella, and other gram negative enterics

Front 6

What bacteria cause meningitis in those ages 1-23 months

Back 6

Streptococcus pneumoniae (50%)
Neisseria meningitidis (30%)
group B streptococci (15%)
Haemophilus influenzae type b (5%)

Front 7

What bacteria cause meningitis in those age 2-18 years

Back 7

Neisseria meningitidis (60%)
Streptococcus pneumoniae (25%)
Haemophilus influenzae type b (9%)
group B streptococci (3%)
Listeria monocytogenes (3%)

Front 8

What bacteria cause meningitis in those age 19-59 years

Back 8

Streptococcus pneumoniae (60%)
Neisseria meningitidis (18%)
Haemophilus influenzae type b (12%)
Listeria monocytogenes (8%)
group B streptococci (2%)

Front 9

What bacteria cause meningitis in those age 60 and up

Back 9

Streptococcus pneumoniae (70%)
Listeria monocytogenes (24%)
Neisseria meningitidis (2%)
Haemophilus influenzae type b (2%)
group B streptococci (2%)

Front 10

What are the general steps in development of meningitis

Back 10

Nasopharyngeal colonization; Local invasion; Bacteremia; Meningeal invasion; Bacterial replication in the subarachnoid space; Release of bacterial components; Decreased cerebral blood flow and loss of cerebrovascular autoregulation

Front 11

How do patients with meningitis present

Back 11

With symptoms and signs related to their systemic illness, the initial focus of infection, and the CNS.
Symptoms and neurological signs in bacterial meningitis include headache, fever, meningismus, altered sensorium, Kernig's sign, Grudzinski's sign, vomiting, seizure, focal findings, and papilledema

Front 12

What is the single most important laboratory test in patients with meningitis

Back 12

Examination of the CSF

Front 13

How should meningitis caused by Neisseria meningitidis be treated

Back 13

Penicillin G or ampicillin

Front 14

What is the mortality rate from community acquired bacterial meningitis

Back 14

5-20%, even with antimicrobial therapy

Front 15

What are the general characteristics of Neisseria

Back 15

Gram negative diplococci; Occur in pairs; Non-motile; Non spore forming
All are aerobic but will multiply under microaerophilic conditions
Oxidase positive-have cytochrome C oxidase as measured by reduction of the dye N,N-dimethylp-p-phenylene diamine

Front 16

How is pathogenic Neisseriae differentiated from non-pathogenic Neisseriae

Back 16

Pathogenic will not grow at 22 C, will not grow on agar without blood, but does require 5-10% CO2 in atmosphere for optimal growth

Front 17

What three antigens are used to classify Neisseria meningitidis

Back 17

Polysaccharide capsule- 12 serogroups. Meningococcal capsular antigens are present in blood and CSF in severe infections. Antibodies to type B capsule cross-react with E.coli K-1 capsule
Lipo-oligosaccharide (LOS)- not LPS, because has short sugar chains rather than multiple repeating units
Outer membrane proteins- antibodies against serotype antigens are bactericidal in the presence of complement

Front 18

What are the characteristics of the Asymptomatic pharyngeal carrier of Neisseria

Back 18

5-25% of population are carriers at any one time
Rates increase in closed population
Carrier state enhances immunity of the host
Low incidence of disseminated disease after colonization in adults, though higher incidence in children

Front 19

Define meningococcemia

Back 19

Meningococci in the blood

Front 20

What are some characteristics of meningococcemia

Back 20

Cutaneous manifestations such as petechiae or purpura
Waterhouse-Friderichsen syndrome, manifests as shock, disseminated intravascular coagulation with bilateral destruction of the adrenal glands. Usually fatal
Meningitis is a common form of meningococcal disease

Front 21

What bacterial disease is associated with C' deficiency (C6, C7, or C8)

Back 21

Chronic recurring meningococcal disease

Front 22

What are the virulence factors of Neisseria meningitidis

Back 22

Capsules are antiphagocytic by interfering with complement deposition and preventing C3b-mediated uptake of the meningococci by phagocytes. Major virulence determinants
Protease which cleaves sIgA (LAMP1)
LOS-a hyperproducer of endotoxin-containing blebs
Pili
Capacity to acquire iron in vivo. Neisseria don't have siderophores

Front 23

Can meningococci survive within PMNs

Back 23

No, they are obligate extracellular parasites. Although meningococci often are seen on gram stains within PMNs, the bacteria are dead

Front 24

What bacteria produce a protease that cleaves sIgA

Back 24

Streptococcus pneumoniae
Neisseria meningitidis
Neisseria gonorrhoeae
Haemophilus influenzae

Front 25

What does recovery from Neisseria meningitidis in untreated cases correlate with

Back 25

Development of IgG bactericidal anti-capsular antibodies

Front 26

What is the epidemiology of Neisseria meningitidis

Back 26

Spread human to human. Asymptomatic carriers are the focus of infection
Highest attack rates in late winter, early spring
Greatest incidence between 6 months and 3 years

Front 27

Which serogroup of Neisseria meningitidis typically causes epidemics in developed nations with attack rates of 50 to 100 per 100,000

Back 27

Serogroup B

Front 28

Where do Neisseria meningitidis serogroup C outbreaks occur

Back 28

Developed and less developed countries. Attack rates can be as high as 500 per 100,000

Front 29

Where does Neisseria meningitidis serogroup A cause epidemics

Back 29

Less developed nations. Attack rates as high as 1000 per 100,000

Front 30

How do patients with bacterial meningitis typically present

Back 30

Headache, fever, and stiff neck. Vascular legions (petechiae and/or purpura) are commonly seen in patients with meningitis caused by Neisseria meningitidis. The CSF typically contains bacteria or polysaccharide capsules, PMNs, elevated levels of protein, and decreased amounts of glucose

Front 31

What Neisseria species are pathogenic for humans

Back 31

Neisseria gonorrhoeae (gonococcus)
Neisseria meningitidis (meningococcus)
The habitats of these organisms are mucosal surfaces. Pathogenic species are not normal flora but may be transient flora in the URT or genital tract without causing disease
Other members of the family Neisseriaceae that can cause disease include Eikenella corrodens and Kingella kingae

Front 32

How is Neisseria meningitidis identified

Back 32

Genera- gram negative diplococci, oxidase positive
Species- Sugar reactions
Serogroup- Agglutination reaction

Front 33

How is Neisseria meningitidis treated

Back 33

Penicillin G. Rifampin, ciprofloxacin, or ceftriaxone are sometimes used

Front 34

How is Neisseria meningitidis immunity achieved

Back 34

Acquired immunity as we get older
Vaccine that contains A,C,Y, and W-135 capsular polysaccharides. C not good for children under 2
Tetravalent conjugate vaccine (MCV4), contains capsular polysaccharide from A,C,Y, and W135 each conjugated to diphtheria toxoid. Vaccine for young adolescents, college freshmen in dormitories, microbiologists, military recruits, travelers, immunodeficiencies, and asplenia

Front 35

Describe Eikenella corrodens

Back 35

Family Neisseriaeaceae. Gram negative ROD, fastidious growth requirements, can pit or corrode agar. Normal flora in URT but cause subacute endocarditis in immunocompromised or oral cavity trauma. Can be part of polymicrobial infection

Front 36

Describe Kingella kingae

Back 36

Family Neisseriaeaceae, looks more like Neisseria (Gram negative coccobacilli). Resides in human oropharynx. Can cause septic arthritis in children, and subacute endocarditis in everyone