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Micro: Neisseria and Branhamella


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Pathogenic Neisseria: common metaboilic Characteristics?
- N. meningitidis, N.gonorrhoeae
- Gram Negative diplococci
- oxidase (+), glucose (+)
- optimal growth on inc. CO2 and chocalate agar
- differentiation by sugar test and slide agglutination

*Martin Lewis: chocalate agar containing antibiotics active against gram(+)bacteria
Pathogenic Neisseria: common pathogenic characteristics?
both species contain pili and outer membrane proteins(OMP), may change antigenically from gen to gen

Contain lipoOligosacchride(LOS)

lipid A and core oligosacchride function as endotoxin
N. Meningitidis: disease states?
upper respiratory meningococcal disease ranging from mild febrile to severe pharyngitis

may progress to systemic meningococcemia presenting w/ fever, weakness, petechial rash

20-40 % progress to meningitis, then arthritis, endocarditis and Waterhouse- Friderichsen syndrome (adrenal coritcal necrosis)
N. Meningitidis: describe the epidemiology?
2-3000 cases of meningococcal disease in US/year with fatality rate 10%

4-10% nasopharyngeal carriers

carrier state is 30-90% as a result of and during epidemics
What makes N. Meningitidis pathogenic?
pili - for ATTACHMENT

IgA protease - colonization, deactivation of IgA

LOS(polysacchride capsule) with sialic acid - interferes with complement

Endotoxin; sheds blebs of toxin

Outer Membrane Protein OMP binds IgG
What are methods used to id/diagnose N. meningitidis?
Gram stain spinal fluid, even buffy coat of blood

Ag detection in spinal fluid

culture spinal fluid, blood and petechiae (*remember CSF, glucose down, protein up)

nasopharyngeal swabs and throat

* there are 12 polysacchride serogroups
N. Meningitidis: Immunity?
most adults have immunity to cidal Abs

newborns have passive immunity

*children 6 mos to 2 yrs are most susceptible

asplenic persons and those with C5, C6, C7 deficiencies are esp susceptible
N. Meningitidis: Rx and Vaccines?
Penicillin in massive doses (is of very little risk to hospital personnel)

vaccine recommended for pts w/ asplenia or complement deficiencies

for families, soldiers use rifampin, ciproflaxin or ceftriazone for prophylaxis

vaccine contains polysacchride capsular antigens, used extensively by military and international travelers
N. gonorrhoeae: What are the disease manifestations common to men and women?
Short incubation 2-7 days

infection of the columnar and transitional epithelia of the urogenital tract

infection makes patients more susceptible to other STDs and HIV

pharyngitis occurs from oral genital sex
N. gonorrhoeae: What are the clinical manisfestations in MALES?
urethral infections subside in several weeks

repeated infections can lead to sequelae

most males present with pain on urination and a purulent pus
N. gonorrhoeae: What are the disease manifestations in FEMALES?
asymptomatic in about 30% of cases but may present with pain on urination , abdominal pain, and vaginal discharge

sequelae inc. fallopian tube inflammation w/ scarring pelvic pain, ectopic pregnacy and recurring PID

Disseminated Gonococcal (DGI) infections can result in septic arthritis and tenosynovitis

Gonococcal perihepatitis (Fitz Hugh Curtis Syndrome) and meningitis are rare complications
N. gonorrhoeae: What are disease manisfestations in children?
opthalmia neonatorum (eye infection) during passage thru birth canal as a reuslt of mom being infected with this bacterium

infection from sexual abuse leads to vulvovaginitis
N. gonorrhoeae: Epidemiologic characteristics?
The risk of getting this infection from an infected partner is 30% for females and 10% for males
N. gonorrhoeae: Describe its pathogenicity?
this bacteria has a pili and OMPs for attachment

Parasite directed endocytosis allows this org to enter cells which are not phagocytic

it forms a LOS/sailic complex

it upregulates catalase inside phagocytes to defend agst killing

Genetic variation in pili and surface Opa proteins help delay Ab reponse
N. gonorrhoeae: Rx and immunity?
30% are resistant to penicillin and tetracycline

Fluoroquinolones are used w/ other antibiotics to cover possibility of multiple infection

repeated infections can occur

lack of immunity is due to genetic variation of gonococci

there is NO vaccine
N. gonorrhoeae: What is the criteria for diagnosis?
this org requires an enriched choclate agar for growth (if taken fron anorectal area)

for women take and endocervix specimen and anal canal culture

Men urine may be used as a specimen but it must be cultured immediately;

for men gram negative intra cellular diplococci on direct smear from urethral exudate is diagnostic

throat cultures
What is the difference btwn Presumptive and Definitive diagnoses of N. gonorrheae?
garam(-) diplococci colonies on chocolate agar w/ antibiotics(thayer-Martin) that are oxidase positive, are adequate in uncomplicated cases
complicated cases where suspect colonies must be subjected to sugar utilization tests or slide agglutination; recommended for sites other than anal or genital region
N. gonorrheae: What are tequniques used for daignosis?
non culture tests which allow gc to be transported or stored over a pd of days

ELISA detect gc antigens

genetic transformation test to detect gc DNA

Nucleic Acid amplification tests, expensive
N. Sicca
N. flvescens
these are other sp. of Neisseria that are normal in the pharynx and can occasionally cause infection
Branhamella (Moraxell) catarrhalis
common commensal in the throat

it causes Otitis media in children
T/F Slide agglutination is the major way to detect cases of pirulent meningitis in the Cerebral Spinal Fluid.
False. Gram stain of CSF can detect bacteria in about 50 % of cases and can be used to distinguish between Hemophilus influenza, Strep pneumoniae, and N. meningitis.

Slide agglutination may also be used as an adjunct but not a substitute for Gram stain.

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