Lecture 12 Flashcards
1
Q
What are the general characteristics of Neisseria?
A
Gram– dipplococci; small nonmotile aerobes that are oxidase-positive, has pili; invasive
2
Q
What is the reservoir for Neisseria?
A
STRICTLY human
3
Q
What exotoxins do Neisseria species produce?
A
no exotoxins have been identified
4
Q
What disease do Neisseria species cause commonly?
A
Gonorrhea
5
Q
What is the second most common bacterial STI in USA?
A
Gonorrhea
6
Q
What is the most (#1) common STI in USA?
A
HPV
7
Q
What is the difference between a disease and infection?
A
one can have an infection without developing a disease
8
Q
Why is using the term “STI” more accurate than using the term “STD”? (infection vs disease)
A
one can be infected but not form a disease and have no symptoms = asymptomatic but can pass on infection to another person who may develop symptoms = disease
9
Q
Who first identified Neisseria species? What year?
A
Albert Neisser (German physician), 1879
10
Q
What is another name for the Neisseria species?
A
Moraxella species
11
Q
What are the 2 Neisseria species discussed?
A
N. gonorrheae and N. meningitides
12
Q
What is another name for N. gonorrheae?
A
Gonococcus
13
Q
What is another name for N. meningitides?
A
Meningococcus
14
Q
What diseases does Gonococcus cause?
A
Gonorrhea
15
Q
What diseases does Meningococcus cause?
A
bacterial meningitis and septicemia
16
Q
How many known Neisseria/Moraxella species are found in humans?
A
10
17
Q
What is gonorrhea (STI) called in the hood?
A
The Clap
18
Q
What kind of pathogen is N. gonorrheae considered to be and why?
A
mucosal pathogen because it colonizes with mucosal epithelial membranes/surfaces
19
Q
What are the 2 characteristics of all mucosal pathogens?
A
cannot survive outside of host and highly sensitive to light
20
Q
What is the mode of transmission of N. gonorrheae?
A
vaginal/anal/oral sex (due to genital secretions) with someone infected (does not need to have the disease)
21
Q
Is gonorrhea a new or old disease? What is the evidence?
A
old bacteria STI infected men from ancient world as well as Biblical references
22
Q
What does “gono” and “rrhea” mean?
A
“gono” = seed and “rrhea” = flow
23
Q
What does “asymptomatic carriage” mean?
A
pathogen is carried mostly via asymptomatic persons
24
Q
What percentage of women are asymptomatic?
A
~20-40%
25
What percentage of men are asymptomatic?
~10%
26
Which gender is more susceptible to develop gonorrhea and why?
men because they are only 10% asymptomatic
27
Which gender is more likely to transmit gonorrhea and why?
women because they are more asymptomatic = will not know IF they are infected
28
What are the common symptoms of gonorrhea in women?
vaginitis (mild), increased vaginal discharge, vaginal bleeding between periods
29
In which gender does painful/burning sensation when urinating occur as a symptom of gonorrhea? What is this due to?
BOTH men and women; due to infection of urethral canal
30
What are the common symptoms of gonorrhea in men?
penile discharge (white, yellow, or green), painful/swollen testicles (less common)
31
What are the symptoms of gonorrhea in a rectal infection?
P-DABS = Painful bowel-movements, Discharge, Anal-itches, Bleeding, Soreness
32
Can symptoms of gonorrhea occur anywhere else in the body other than the reproductive tract?
Yes, like in the liver and pharynx
33
What is gonococcal conjunctivitis?
N. gonorrheae causes an eye infection in newborns from their infected mothers
34
How does gonococcal conjunctivitis occur?
women infected with N. gonorrheae (asymptomatic or not) pass the pathogen to the newborn via delivery thus affects eyes of the newborn
35
How can gonococcal conjunctivitis be prevented?
via prophylactic treatment where drops of erythromycin are applied onto all newborn's eyes to prevent infection in case if the mother is infected
36
How many new cases/year of gonorrhea in the US? Is this an estimation or exact? Who does it include?
~700,000 = estimation as it includes reported cases and unreported asymptomatic cases of infected individuals
37
What are 3 reasons for the many cases of gonorrhea?
1) acquired immunity doesn't exist = can get reinfected | 2) use of oral contraceptives = help bacteria colonize | 3) symptoms in females may be mild = undetect disease = pass to sexual partners
38
Between bacterial STIs and viral STIs, which is more treatable and why?
bacterial STIs = antibiotics available; antibiotics cannot treat viral STIs
39
What is the 3rd most common STI in US?
syphillus
40
How can one bring a rare STI to the US?
when one travels out of the country and has unprotected sex
41
Which region of the world has the highest cases of gonorrhea?
Africa
42
Which part of the US has the highest occurrence of gonorrhea?
south-east USA
43
Which ethnic group in the US does gonorrhea highly occur in?
African-Americans
44
What is the reason for the decline in gonorrheal cases (US) during 1945-1955?
war and production of antibiotics
45
What is the reason for the increase in gonorrheal cases in the US during the 1960s?
sexual revolution #hippienation
46
What is the reason for the decline in gonorrheal cases in the US from 1981?
increase awareness of STIs due to increase awareness of AIDS and HIV = more people started practicing safe sex
47
What are the 5 virulence factors of N. gonorrheae?
pili, Opa surface proteins, IgA1 autotransporter, Lipo-oligosaccharide and peptidoglycan endotoxins
48
What is the function of the pili in pathogenesis?
bind to surfaces
49
What is the function of the Opa in pathogenesis?
bind to mucosal epithelial and phagocytic cells ; cell-cell signaling
50
What is the function of the IgA1 autotransporter in pathogenesis?
acts as a protease cleaving IgA1 antibodies
51
What is significant about the mechanism of the IgA1 autotransporter of N. gonorrheae?
these bacteria have been "born" to fight the host immune system at mucosal surfaces by releasing the IgA1 protease = will degrade and inactivate the IgA1 antibodies | makes sense because gonorrhea=old disease=N. gonorrhea knows how to attach mucosal epithelial cells
52
Where are IgA1 antibodies found?
on mucosal surfaces
53
What is the difference in the mode of invasion between Gonococcus and Meningococcus?
Gonococcus = no capsule = infection remains localized only to mucosal epithelial surfaces | Meningococcus = has capsule = infection not localized = can enter bloodstream and infect other organs
54
What is antigenic variation and how does it occur?
changes in the composition/structure of "main" surface molecules on bacteria's cell surface = allows them to avoid recognition by specific antibodies during the course of an infection | happens via random genetic rearrangements (change sequence = change structure)
55
What structure on N. gonorrheae undergoes antigenic variation?
the pili
56
What is the consequence of the antigenic variation mechanism of N. gonorrhea on us the hosts?
contributes to the lack of protective immunity during infection because the immune system never recognizes the bacteria, its always under some disguise = why people can be reinfected
57
What are the 2 mechanisms N. gonorrhea uses to escape detection by the immune system?
antigenic variation and phase variation
58
What is phase variation?
genes that encode for the specific outer-membrane proteins contain repeats | change the number of repeats = change sequence = change structure
59
What structure on N. gonorrheae undergoes phase variation?
the Opa proteins
60
What are the 4 methods of diagnosis to detect/identify presence of N. gonorrheae?
1) swab of discharge from infected area | 2) microscopy-Gram stain | 3) culture on selective media, biochemical assays | 4) PCR (4hrs, sensitive/specific)
61
What was the first antibiotic used to treat gonorrhea and why is it no longer recommended for treatment?
penicillin, many penicillin-resistant strains
62
What are 2 examples of antibiotics used for treatment?
quinolones and cephalosporins (= QuinoCephs)
63
What is a rising problem in the treatment of gonorrhea, what is N. gonorrheae then considered as?
multi-drug-resistant strains on the rise - considers N. gonorrheae to be a Super Bug :(
64
Are there vaccines available to prevent N. gonorrheae infections? Explain.
No vaccines available due to: changes (hyper-variablility) of surface proteins | blocking antiboies like the IgA1 autotransporter | N. gonorrheae spends most of time inside host = intracellular resistance (evolved to fight off host defenses)
65
What is the reservoir for N. meningitides?
human
66
What is the mode of transmission for N. meningitides?
direct contact and airborne; asymptomatic carriage also possible
67
What are the 5 most common serogroups of N. meningitides?
A, B, C, W-135, Y
68
What is bacteremia?
BACTERIA in the blood
69
What is septicemia?
INFECTION in the blood
70
What does the type of infection of N. meningitides that we have refer to?
infection of the membrane that surround the brain
71
What are the 2 stages of bacterial meningitis?
1) bacteria enters blood and colonizes meninges | 2) inflamed meninges allows phagocytes and blood proteins to enter spinal fluid and brain
72
What is the sequence of events of bacterial meningitis?
bacteria enters host via respiratory system >> it crosses mucosal epithelial cells >> enters bloodstream >> lands on central nervous system, colonizes membranes of CNS and brain
73
What causes the inflammation of the meninges?
the infection, colonization of the meninges
74
What is responsible for most of the damage and why?
the inflammation causes/allows blood proteins and phagocytes to enter the spinal fluid and brain
75
What are the initial symptoms of bacterial meningitis?
fever, rash, stiff neck, headache (= FRSH)
76
What percent of cases lead to death and what is significant about this?
3% and includes individuals that have been treated with antibiotics
77
What are the virulence factors of N. meningitides?
capsule and LOS endotoxin
78
What specimen is collected for diagnosis?
blood
79
What are the methods to diagnose/detect the presence of N. meningitides?
culture, microscopy, PCR-based assay
80
What antibiotics are used to treat bacterial meningitis?
cephalosporins & penicillin (CephaPen)
81
How many vaccines are available to help prevent infection due to N. meningitides?
4
82
What are the vaccines that contain the capsular polysaccharide serogroups?
Meningococcal ACWY vaccine (A, C, W-135, Y serogroups included) and Meningococcal B vaccine
83
Which vaccine is ineffective on infants and why?
Meningococcal ACWY vaccine because it does not contain the B serogroup
