Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Pathogenic Microbiology > Exam #3 > Flashcards

Exam #3 Flashcards

1
Q

Neisseria gonorrhoeae:

Outline

A

gram negative diplococci
fastidious- requires blood and increased CO2
naturally competent for DNA transformation
capable of conjunction- large plasmid
-may possess antibiotic resistance genes
-encoded transposons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Neisseria gonorrhoeae:

Epidemiology

A

transmitted via mucosal surfaces and infected secretions

-nonsexual transmission rare

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Neisseria gonorrhoeae:

Disease Presentations

A 
asymptomatic infection
urethritis
cervicitis
-inflammation of endocervical canal
-mucopurulent discharge
-abscess formation in paracervical (Bartholin's) glands
vulvovaginitis
-pre-adolescent women and post-menopausal
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Neisseria gonorrhoeae:

Diseases

A

opthalmia neonatorum
-acute purulent conjunctivitis in newborns
-acquired via passage through the infected birth canal
epididymitis/prostatitis
-common in males under 35
-sterility is post-infection complication
pelvic inflammatory disease (PID)
-peritoneal spread (Curtis-Fitz-Hugh Syndrome)
-infertility is a complication (fallopian tube damage)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Disseminated Gonococcal Infection (DGI)

A

hematogenous spread
-effects skin and joints
*hemorrhagic papular lesions- fingers, wrists, feet
*arthritis- #1 cause of septic arthritis in adults
-endocarditis and meningitis (rare)
complement deficiency is higher risk

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

DGI:

Diseases

A 
rectal infection
-generally asymptomatic
-can result in tenesmus, local pain, pus on defecation
pharyngeal infection
-generally asymptomatic
-can result in sore throat
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Gonococcal Pathogenesis:

Adherence

A

adheres and invades the epithelial cells

  • non-ciliated cells of fallopian tubes
  • cilitated cells damaged through indirect process
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Gonococcal Pathogenesis:

Bacterial Phase Shift

A

antigenic variation: pili and opacity proteins
phase variation: ability to quickly turn genes on and off
-reversible and non-reversible
-Pili and Opa proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Gonococcal Virulence Factors:

Pili

A

mediate adherence to eptihelial cells and spermatozoa

subunit (pilin) is component of structure that varies: immune avoidance strategy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Gonococcal Virulence Factors:

Opacity (Opa) Proteins

A

mediate adherence and kinvasion
12 different
each undergoes phase variation
-open reading frame (ORF)- shift mechanism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Opa Phase Variation

A

facilitates survival in high progesterone levels
-Opa+ bacteria isolated during proliferative stage of the menstral cycle
-Opa- bacteria isolated during luteal stage
in vitro studies
-Opa+ more sensitive to progesterone than Opa- variants

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Gonococcal Virulence Factors:

Lipooligosaccharide (LOS)

A

shorter form of LPS
membrane blebs of GC contain this component
phase and antigenic variation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Gonococcal Virulence Factors:

Iron-Binding Proteins

A

expressed under low iron

compete w/ transferrin, hemoglobin, lactoferrin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Gonococcal Virulence Factors:

IgA Protease

A

cleaves IgA1 (secretory IgA) at mucosal surfaces

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Gonococcal Lab Identification

A 
chocolate agar + increased CO2
growth after 1-2 days incubation
carbohydrate utilization
-both glucose
-both can't use lactose
-meningitidis can use maltose, gonorrhoeae cannot
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Gonococcal Treatment:

Penicillin

A

no longer drug of choice

  • penicillinase-producing N. gonorrhoeae (PPNG) exists
  • acquired from H. ducreyi plasmid
  • resistance via mutated PBPs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Gonococcal Treatment:

Tetracycline

A

resistance gene carried by transposon on large conjugative plasmid
some strains resistant to both penicillin and tetracycline

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Gonococcal Treatment

A

ceftriazone is drug of choice
some isolates also resistant to other classes of antibiotics
-fluoroquinolones
-spectinomycin
vaccine unavailable due to lack of capsule and Ag variation being problematic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

C. trachomatis

A

trachoma serovars A, B, Ba, C
adult inclusion conjunctivitis sero’s D-K
most common VD in US
non-gonococcal urethritis: acute epididymitis
-irritation and discharge
persistant urethral leukocytosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

C. trachomatis:

Serovars D-K

A

acute urethral syndrome; cervicitis; PID
-most females asymptomatic
-symptoms are subtle
-sterility, ectopic pregnancies, miscarriages, low birth weight
neonatal infections
-ocular: acute mucopurulent eye discharge
-most common form of neonate conjunctivitis in US
-interstitial pneumonia- gradual onset; no fever

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

C. trachomatis:

L1, L2, L2a, L3

A

lymphogranuloma venereum (LGV)

  • tropism of lymphoid tissue
  • primary lesion: small painless vesicle on or near genitalia
  • regional lymphadenopathy after several weeks
  • buboes w/fever, headache, myalgia, arthralgia
  • late phase sequelae
  • perirectal ulcers, fistulas, urethral strictures, fibrosis, elephantiasis
  • many infections inapparent
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Treponema spp.:

General Characteristics

A

genus composed of three pathogenic spirochete species
-T. pallidum; T. pertenue; T. carateum
corkscrew motility via axial filaments
-can move through high viscosity media
difficult to visualize microscopically
-too thin, need to use dark field
T. pallidum cannot be grown outside tissue culture or live animals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Syphilis:

Epidemiology

A 
12 million cases per year
highly infectious
-aggressively infets mucous membranes
-sexual and congenital transmission
-can infect by direct contact
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Syphilis:

Primary Pathogenesis

A

formation of a chancre at site of infection

  • 2-10 weeks
  • painless ulcer
  • heals spontaneously
  • infection systemic at this point
  • genital sites–> increased risk of HIV
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Syphilis: | Secondary Pathogenesis
multiple lesions, 2-10 weeks post chancre -skin- papulosquamous rash -mucosal lesions- condylomata lata systemic infection becomes asymptomatic after disappearance of rash resolution of disease in 1/3 of infected rare sequelae of secondary syphilis -meningitis, iritis, hepatitis
26
Syphilis: | Latent Pathogenesis
``` asymptomatic can last years post-infection secondary lesions in 25% infectivity of body fluids declines resolution of disease n 1/3 of infected ```
27
Syphilis: | Tertiary Syphilis
*neurological (CNS) meningovasculitis and parenchymal degeneration chronic meningitis -fever, headache, ocular involvement, cortical degeneration of brain tissue -behavioral disturbances - paresis *cardiovascular medial necrosis and loss of arterial elasticity -aortic valve disfunction, aneurysm *lesions gummas (syphilomas) and/or syphilids
28
T. pallidum: | Virulence Factors
``` poorly characterized lacks numerous surface-expressed proteins tpr genes -12 proteins -adhesions and/or porins hemolysins -5 genes -products my be cytolytic ```
29
T. pallidum: | Virulence Factors cont.
``` gcp gene -encodes a sialoglycoprotease (degrades host glycoproteins) ankA and ankB -encode homologs of mammalian ankyrin 3 iev -encodes an integral membrane protein -possible immunosuppressive effects ```
30
T. pallidum: | Diagnostic Procedures
``` direct observation of bacteria from lesions -dark field microscopy serology -RPR: Rapid Plasma Reagin *non-treponemal-based on cross-reaction of anti- T. pallidum with cardiolipin from beef heart *not very specific -FA: fluorescent antibody staining *confirms RPR ```
31
T. pallidum: | Treatment and Immunity
- penicillin drug of choice for all stages of the disease - tetracycline or erythromycin also effective - antibody response to OMPs * contributes to host resistance to re-infection - CMI resolves lesions but does not clear bacteria
32
Haemophilus ducreyi
``` gram negative coccobacillus -may be pleomorphic and gram 'variable' non-motile fastidious- needs hemin -chocolate agar will support growth -elevated CO2 better ```
33
H. ducreyi: | Disease
ST etiology of chancroid or 'soft chancre' 10x's more prevalent in males short incubation: 2-5 days -ragged ulcer on genitalia with marked swelling and tenderness -regional lymph nodes enlarged associated with poor hygiene and poor socioeconomic conditions
34
H. ducreyi Virulence Factors: | HdCDT
Haemophilus ducreyi cytolethal distending toxin | -progressive apoptosis of antigen presenting cells
35
H. ducreyi Virulence Factors: | Outer Membrane Proteins
LspA1, LspA2 - 456 and 543 kDa - anti-phagocytic properties
36
H. ducreyi Virulence Factors: | DltA
ducreyi lectin A | -serum resistance
37
H. ducreyi Virulence Factors: | flp Gene Cluster
15 genes type IV secretion tadA: reduced lesion formation if mutated
38
H. ducreyi Virulence Factors: | SOD
superoxide dismutase | -may also be involved in iron acquisition
39
H. ducreyi Virulence Factors: | pCb
low molecular weight plasmid | -encodes beta-lactamases
40
Ureaplasma urealyticum
``` single species in genus related to mycoplasma large: 0.2-0.3 mm; pleomorphic -no cell wall- has a three layer membrane *contains sterols- scavenged from hose *slow growers on enriched mediea 14 serotypes produces urease- primary virulence factor ```
41
Ureaplasma: | Diseases
urethritis in males - very common chorioamnionitis and postpartum fever in females tetracycline is drug of choic -will also work against Chlamydia
42
Mycoplasma hominus
numerous species - only two pathogenic -M. pneumoniae, M. hominus M. hominus associated with genitourinary tract -commonly causes postpartum fever (self-limiting) -also, pelvic inflammatory disease -CNS and joint involvement, but rare responds to tetracycline
43
Borrelia Species: | Principle Pathogenic Species
B. recurrentis: epidemic relapsing fever B. hermsii: endemic relapsing fever B. burgdorferi: Lyme disease -12 other species associated with human disease
44
Borrelia Species: | Morphology
'classic' spirochete long: 10-30um more axial filaments than treponemes visualized by Giemsa or Wright stain
45
Borrelia Species: | Cultivation
some can be cultivated fastidious: require long-chain fatty acids, ect. microaerophilic
46
B. hermsii
``` etiologies of relapsing fever tick (ornithodoros species) -'endemic' rf *rodent primary reservoir *ticks will also maintain bacteria transovarially ```
47
B. recurrentis
``` etiology of relapsing fever louse-borne -'epidemic' rf *humans are the only host *areas of poor hygiene and dire poverty ```
48
Relapsing Fever
average incubation time = 7 days bacteremia w/febrile episodes (days) -each relapse duration: 2-4 days -one to 4 cycles before resolution (afebrile intervals: 7-9 days) mortality -tick-borne: very low! -louse-borne: up to 40%! (due to myocarditis, hepatic failure, ect.)
49
Relapsing Fevers
total systemic involvement no bacteria in blood during 'down time' relapsing cycles correlate with antibody production antigenic phase-shift
50
B. recurrentis and B. hernsii: | Virulence Factors
OMPs and lipoproteins - phase vary at high frequency (~40 different phenotypes/proteins) - mechanism: recombination between genes on linear plasmids - protective humoral immunity when bacterium exhausts phenotypic repertoire
51
B. burgdorferi
``` etiology of Lyme disease -follows sylvatic cycle growth in vitro -slow, doubling time 8-24 hours -may take days to weeks to isolate 10 different sub-species ```
52
B. burgdorferi: | Epidemiology
localized distribution in US due to anthropogenic factors tick-vectored -most common arthropod-vectored infection in US -eggs-->larvae-->white-footed mouse-->nymphs-->deer-->maturation/mating
53
B. burgdorferi: | Disease Presentation
erythema chronicum migrans (ECM) -at bite sites, small papule, turns into bull's eye fever, fatigue, myalgia, headache that last more months secondary rash half the time 'stage #2' day to weeks post-infection: neurologic/cardiac symptoms weeks, months, years post-infection: chronic arthritis; encephalitis
54
B. burgdorferi: | Virulence Factors
``` OspA-->OspC adhesins -targets integrins, platelets, and collagen LPS peptidoglycan -inflammatory properties immune-mediating toxins ```
55
Relapsing Fever: | Diagnosis and Treatment
direct examination of blood serologic tests tetracycline or erythromycin effective at a single dose
56
Lyme Disease: | Diagnosis and Treatment
clinical findings direct examination, PCR/serology doxycycline IV; ceftrioxone for more serious -response to treatment is slow --> requires 30-60 days
57
Borrelia Vaccine
``` discontinued insufficient consumer demand recombinant OspA... the tick protein antibodies target the arthropod mid-gut localized bacteria pathogen is killed at point of enetry ```
58
Leptospira Species
``` L. interrogans in humans (over 200 serotypes) other species are free-living more 'tightly-wound' spirochete -very thin-viewed in dark field only -single axial filament can be cultivated in vitro -aerobic; fastidious -killed in an acidic environment -survival for weeks in water ```
59
Leptospirosis: | 'Swamp Fever'
occurs world-wide (100-200 in US yearly) zoonotic disease -wild and domestic animals (rodents, cattle, dogs) -transmitted to humans through contaminated water -farmers and slaughterhouse workers at highest risk
60
Leptospirosis: | Pathogenesis
site of inocculation is through break in skin or mucosal surface rapid systemic spread to include CSF -also renal tubules and kidneys in animals
61
Leptospirosis: | Virulence Factors
23 potential virulence genes by subtractive hypbridization | evidence for apoptotic effectors
62
Leptospirosis: | Disease Presentation
``` most infections asymptomatic 7-13 days incubation time flu-like symptoms -fever, chills, headache, myalgia -associated w/bacteremia and CSF inflitration (1 week duration) ```
63
Leprospirosis: | Stage 2
``` *bacteremia disappears aseptic meningitis -usually 3 weeks in duration -resembles viral meningitis -other generalized symptoms *myalgia, rash, renal and hepatic involvement -severe form: Weil's disease *extensive vasculitis; jaundice; renal damage; hemorrhagic rash *10% mortality ```
64
Leptospirosis: | Diagnosis and Treatment
serologic tests (including slide agglutination) culture not useful as it takes weeks organism sensitive to beta-lactams or tetracylcine
65
Corynebacterium Species
``` pathogenic -C. diptherieae -C. ulcerans and C. pseudotuberculosis -C. jeikeium (on immunosuppressed) -group D-2 coryneforms/ UTIs (C. urealyticum) low virulence -'diptheroids' ```
66
C. diphtheriae: | Characteristics
``` humans are reservoirs- URT and skin gram+, club shaped, non-motile non-spore forming, catalase + stained organisms resemble Chinese letters three biotypes -gravis, mitis, intermedius ```
67
C. diphtheria: | Diseases
URT infection: toxinogenic strains -low-grade fever and sore throat -adherent pseudomembrane (tonsils/pharynx) cutaneous infection: Tox+ or Tox- strains -insect bites, wounds, co-infected lesions -tropical climate toxic complications -myocarditis/ polyneuritis
68
C. diphtheria: | Pathogenesis
non-invasive respiratory symptoms from local effects of toxin -pseudomembrane from back of throat to trachea -cervical adentitis/edema/'bull neck' -respiratory obstruction -systemic effects *myocarditis- arrythmia, congestive heart failure *CNS- paralysis
69
C. diphtheria: | Diphtheria Toxin
encoded by toxin-converting phage expression under low iron -repressor upregulated in presence of iron A/B subunit toxin -its expressed as a single polypeptide -B fragment- receptor binding -A fragment- internalized enzymatic activity
70
C. diphtheria: | Other Virulence Factors
iron acquisition proteins and siderophores

Pathogenic Microbiology (3 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions