STO's and Neisseria meningitidis Flashcards Preview

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Flashcards in STO's and Neisseria meningitidis Deck (88):
1

Treponema pallidum shape and visualization techniques

Thin spirochete

  • Visualized in fixed tissues by silver stain
  • Visualized live by dark field microscope

*Not visible using light microscopy

2

Treponema has a _____ that surrounds the whole cell

 

It is motile due to.....

It has a GAG sheath surrounding the whole cell

 

Motile due to endoflagella within periplasm (THREE at each end)

3

Treponema envelope composition

  • No LPS
  • Loosely anchored OM containing cardiolipin
  • Mostly IM lipoproteins (OM few)

4

Lab culture technique for treponema

Can't culture in lab!

Cultivate in rabbit testes

 

*has microaerophilic metabolism

5

Primary treponema presentation

  • Chancre = Ulcerated defined papule at infection site
  • Regional lymph node swelling
  • heals spontaneously, but organisms remain

6

Secondary treponema presentation

  • Maculopapular rash anywhere on body (palms/soles)
  • Condylomas in moist areas
  • Heals spontaneously, recurs for 8 months, then latent for 20 years

7

How many patients progress to tertiary syphillis?

About 40%

8

Tertiary syphillis: where's the lesion?

throughout the body

*due to immune response, not bacteria

9

How does tertiary treponema affect particular tissues?

Skin: gummas

Bones: porous, fragile

Heart: aorta swells, ruptures

Liver: ??

CNS: paresis in brain, tabes dorsalis in spinal cord

10

Neurosyphillis can occur...

during secondary or tertiary stages

11

Vertical transmission of treponema?

Yes, it can cross the placenta

  • 20% aborted, stillbirth
  • 80% congenital defects

12

What does congenital syphillis present as?

Hutchinson's triad

  1. Interstitial keratitis (blindness)
  2. 8th nerve deafness
  3. Hutchinson's teeth

*also saddlenose, cognitive deficits, and bone deformation

13

Treponema reservoirs and transmission?

Only human, only STD

 

(can artificially infect rabbits, but they don't progress beyond the Primary stage

14

When is treponema contagious?

 

Only for the first 3-5 years

15

Who should be tested for syphilis?

High risk populations

Pregnant women at 28 weeks and at delivery

After any stillbirth

16

Pathogenic factors (4) for treponema

Highly infectious (10 organisms)

Hyaluronidase (facilitates spread and invasion)

Motility

Few surface proteins (hide from immune system)

17

______ lesions are full of treponema organisms

Primary and secondary

18

(General) control measures for treponema

ID sexual contacts

Scrape chancres (only if active infection, not latent)

Serologic testing

19

Indirect serologic tests for treponema

induce formation of reagin in host (IgM+IgA)

  • add cardiolipin to patients serum
  • If positive, the reagin will cause cardiolipin to clump
  • ****False positives possible***

FTA test (detect anti-treponema antibodies)

  • bind treponema to slide and add patient's serum
  • add a fluorescent anti-human 2' antibody to detect the 1' antibody

20

Direct serological tests for treponema

FTA test (can also be indirect)

  1. Fix anti-treponema antibodies to slide, and add patients serum
  2. Add fluorescent anti-treponema antibodies to detect organisms

21

Syphilis Tx

Pen G (2.4 MU)

Early disease = One injection

Latent disease = Three injections

 

*Salvorsan (arsenic) was used before 1940

22

Neisseria gonorrhea organism shape and location (in cells)

Gram (-) , Coffee-bean shaped diplococcus

Intracellular and inside PMN's

23

N. gonorrhea growth characteristics

  • Fastidious (grow on MTMor chocolate blood agar)......better with selective media (vanco,colistin)
  • Aerobic growth but prefers 5% CO2 (candle jar)
  • Cytochrome C oxidase ++

24

Ox+, Gram(-) diplococcus =

Neisseria

25

Neisseria genome

Two identical chromosomes (diploid) -- never heterozygous

26

Neisseria invades what tissues?

What are the infections that this causes?

invades mucus membranes of the UGT, rectum, eye, throat

Proctitis, pharyngitis, arthritis, dermatitis (rare)

 

27

Male N. gonorrhea infections

Urethritis

*40% asymptomatic

28

N. gonorrhea female infections

  • Urethritis, vaginitis
  • Cervicitis, salpingitis, PID, peritonitis

-->> fallopian tube scarring and infertility (even if asymptomatic...60%)

 

29

Neonatal N. gonorrhea infection

Conjunctivitis

(from infected birth canal)

30

Animal carriers of N. gonorrhea

None. Exclusively human

31

Infection and coinfectino rates of N. gonorrhea

75% of people who sex an infected person (50% after one time)

40% coinfect with Chlamydia

32

N. gonorrhea diagnosis

Males = gram stain of urethral discharge

Females = culture of cervical/vaginal swab

33

N. gonorrhea virulence factors

  1. Pili
  2. Proteins 1-3
    1. Por
    2. Opa
    3. Rmp
  3. IgA protease
  4. LOS
  5. Peptidoglycan release
  6. Fbp

34

N. gonorrhea virulence factors for ATTACHMENT

pili (initial)

  • Antigenic variation via cassette switching  -- avoid host immune response
    • One promoter (PiliE), many genes (PiliS)
    • recombine new piliS gene or part of gene with piliE

OPA protein = "Protein 2" (tight attachment)

  • antigenic variation by DNA slippage of repeats
  • infections in females change Opas during menstrual cycles

 

35

N. gonorrhea virulence factors for EVASION (3)

Por = protein 1

  • Outer membrane porin
  • Prevents phagolysosome fusion

Rmp = protein 3

  • Prevents antibody binding to Por and LOS in the outer membrane

IgA protease

  • prevents complement activation
  • Stops IgA response (first-response Ab in mucus membranes)

36

N. gonorrhea virulence factors for TOXICITY (2)

Lipooligosaccharide (rather than LPS)

  • Lipid A = toxic in all Gram (-) bacteria (endotoxin)
  • Oligosaccharide mimics hist cell membrane structure
  • NANA transferase = sialylates bacterial LOS with host NANA

Peptidoglycan release by autolysins

  • At low temperature or alkaline pH

37

"Other" N. gonorrhea virulence factor

Fbp

Scavenges iron from human lactoferrin and transferrin

38

What is PPNG?

Penicillinase-producing N. gonnorhea

* produces beta-lactamases

39

Other type of resistant gonorrhea?

Pan-resistant NG

**to ALL available antibiotics

40

Tx for N. gonorrhea

Ceptriaxone (i.m.) + Cefixime (oral)

PLUS

Doxy or erythromycin for chlamydia co-infection

 

**NO DOXY DURING PREGNANCY

41

Treat N. gonorrhea sexual partners with...

Cefixime

42

Neonatal N. gonorrhea infection treatment?

Tetracycline drops (for conjunctivitis)

**no longer use AgNO3

43

Neisseria meningitidis structure

Like the gonococcus, but has polysaccharide capsule

44

Types of N. meningitidis

12 types

Common: A, B, C, Y, W135

45

N. meningitidis initially invades ______, causing ________ (infection)

It presents as ________ and small hemorrhages. Why?

 

Invades bloodstream--> meningococcemia

Purpura (75%) -- because blood vessels become more permeable in response to the toxic effects of LOS and soluble peptidoglycan

46

15% of N. meningitidis cases involve

meninges (meningococcal meningitis)

  • acute headache, vomiting, stiff neck

 

47

Cellular findings in meningococcal meningitis?

 

This may progress to...

PMN lymphocytes in CSF (d/t increased vascular permeability)

Brain covered in purulent exudate with PMNL's and N. meningitidis

 

--> may progress to DIC and circulatory collapse = meningococcal septicemia

48

N. meningitidis is ______ in 10% of people

resident flora

49

N. meningitidis spread is helped by __________

pilin modification

--with phosphatidylglycerol

--disrupts microcolony and spreads the organism

50

N. meningitidis is chiefly spread by

respiratory droplets, especially in crowded areas and with susceptible populations

51

Common environments (examples) for spread of N. meningitidis

College dorms and military barracks

52

Once N. meningitidis epidemic begins, there is a ____ carrier rate. This necessitates ________

80% carrier rate

 

Prophylaxis for control of epidemic

53

Most N. meningitidis epidemics are due to...

specific capsular antigen types

54

N. meningitidis virulence factors...

all of the ones from N. g.

PLUS

  1. Antiphagocytic polysaccharide capsule
    • Antigen B is sialylated = much more disguised
  2. Special Pili that attach to BBB and recruit junction complexes, depleting them in other areas of the BBB (increasing permeability)
  3. Additional Adhesins (in outer membrane)

55

N. meningitidis vaccines

(current and newly approved)

NmA vaccine = general prophylaxis

ACWY conjugate vaccine = US use (dorms, army, etc)

 

NmB vaccines = recently approved

  • Bexsero = 3Nm proteins + PorA
  • Trumenba = 1 recombinant lipidated proteinfrom 2 NmB strains

56

Preferred N. meningitidis treatment

3rd gen Ceph

(may include acyclovir too if CSF suggests herpes present (RBC/WBC)

57

Initial treatment of N. meningitidis should be...

 

broad spectrum antibiotic

including Vancomycin (will penetrate BBB)

58

_____ or ______ can be used for prophylactic N. meningitidis treatment in epidemic settings. Why these in particular?

Rifampin or 3rd gen Ceph

 

** they cross the BBB

**can also use high-dose ciprofloxacin

59

Other Neisseria

(Carrier rate, infections in kids and adults, and Tx)

Moraxella catarrhalis

  • 50% carrier in school aged kids
  • infections = opportunistic sinusitis, bronchitis, PNA
  • May also present as Otitis Media (3rd most common cause)
  • Exacerbates COPD in adults (attach to ECM)
  • Produce BETA LACTAMASES = Treat wth Ceph3 or with Cipro (or not at all?)

60

Chlamydia trachomatis organism, genome,and structure

  • Obligate intracellular parasite
  • Small genome (lacks metabolic genes, steals ATP from host)
  • Cell wall lacks MurNAC, but has PBP's
    • Susceptible to Penicillin but not to lysozyme (PEN NOT USED TO TREAT)

61

Chlamydia trachomatis has ___ serovariants, baed on ____

15 serovariants

based on LPS antigens

62

Must cultivate Chlamydia trachomatis on ________

eukaryotic host cells

(embryonated chicken eggs, McCoy cells in monolayer tissue cultures, mouse brains)

 

63

Two life cycle forms of Chlamydia trachomatis

Elementary bodies

  • .3um in diameter, electron dense nucleoid tough membrane (S-S)
  • INFECTIVE FORM   (the form that enters cell)

 

Reticulate bodies

  • 1um diameter, diffuse EM staining, fragile (SH-HS), more ribosomes
  • REPLICATIVE FORM   (the one that divides)

64

Chlamydia trachomatis life cycle (7 steps)

  1. Entry
  2. Initial attachment (surface sugars), actin remodeling, induced uptake
  3. Vacuole
  4. Elementary body metabolism
  5. Develops into RB
  6. RB matures
  7. Release

 

65

Eye infection of Chlamydia trachomatis

(Aquisition and symptoms/pathology)

Trachoma

  • infection at birth or early childhood via flies
  • mucopurulent discharge --> pannus forms (keratinized cornea)
  • Corneal obscuration and trichiasis
  • Permanent blindness

Tx = oral Azithromycin (mass trial showed reduced infective rate by 50%)

66

Other eye infection of Chlamydia trachomatis (the less severe one)

 

(who does it infect, and possible complications)

Inclusion conjunctivitis

  • mostly in neonate (adult from self-innoculation of conjunctiva)
  • may be respiratory complications

67

Chlamydia trachomatis neonatal (non-eye) infection

(Symptoms and Dx?)

Neonatal PNA

  • Shortness of breath
  • NO FEVER
  • suspect if infant has inclusion conjunctivitis

68

STD version of Chlamydia trachomatis?

Chlamydia

69

Male Chlamydia STD symptoms

 

  • non-gonococcal urethritis
  • epididymitis
  • prostatitis

 

(usually self-limiting)

70

Female chlamydia STD symptoms

  • urethritis
  • cervicitis
  • salpingitis/PID (most common cause)

(**Fallopian scarring may lead to infertility or predispose to ectopic pregnancies -- 10 fold increase in likelihood)

71

Most common cause of acquired infertility in females?

Chlamydia induced PID

72

Latent infection of Chlamydia trachomatis?

General infection timeline?

Lymphogranuloma venereum

(small abcess--> heals quickly --> inguinal buboes later)

 

**must Ddx from PLAGUE buboes

73

Latent Chlamydia infection may become ______. This could lead to ______ or ______ due to fibrous restrictions of lymphatic system.

Chronic

elephantiasis or bowel obstruction

74

Specific manifestation of latent Chlamydia depends on...

Serovar of the organism

75

Probability of infection by sex with partner who is infected with Chlamydia trachomatis?

68%

76

Most common Chlamydia trachomatis infections in North/South America and Europe?

What about Asia and Africa?

NA/SA/Eur = STD

Asia/Africa = Trachoma

77

Why do we need to treat both epidemiological localizations of Chlamydia trachomatis the same?

They can cross-infect

78

Chlamydia trachomatis infectiveness is caused by _______

Elementary Bodies

--binding to a host receptor and inducing Pathogen-mediated endocytosis

79

_____ remodels the host cytoskeleton in Chlamydia trachomatis pathogenesis

T3SS

80

Chlamydia inhibits ______ so it can proliferate intracellularly

 

phagolysosome fusion

81

Chlamydia trachomatis induces _______

Cytokine (IL-1) production

82

Chlamydia vaccine?

What is the preferred treatment? Prevention?

Vax = ineffective d/t intracellular location

 

Tx = Azithromycin (one dose oral)

  • Can also treat with Tetracycline or macrolides

Prevention = surgery or epilation for trichiasis to prevent keratinization of the cornea

 

** ID partners -- expidited partner therapy, legal in 35 states

 

83

C. pneumoniae may have originated as a _____ from what?

zoonosis from koalas

84

C. pneumoniae infection rate

100%, but mostly asymptomatic

85

C. pneumoniae may progres to....

Walking PNA (like mycoplasma)

86

C. pneumoniae is found in ______, which suggests...

 

atherosclerotic plaques

 

suggests link to atherosclerosis and coronary artery disease

 

** also associated with asthma, stroke, and late-onset Alzheimer's

87

C. pneumoniae Tx

usually untreated

Tetracycline may help

88

C. psittaci presentation, transmission, and Tx/control

  • Severe PNA, sepsis with patchy, well-defined lung involvement
  • Transmitted via contact with psittacine birds (bites or inhalation of dried feces)
  • Control with tetracycline and quarantine of imported birds