Microbiology Flashcards
1
Q
All DNA viruses are double stranded except
A
Parvovirus (single stranded)
2
Q
All DNA viruses replicates in the nucleus except
A
Poxvirus (Cytoplasm)
3
Q
All DNA viruses are has icosahedral capsid except
A
Poxvirus (complex)
4
Q
All DNA viruses has linear genome except
A
Papillomavirus
Polyomavirus
Hepadnavirus
(circular)
5
Q
A mnemonic for DNA viruses
A
PARdon PAPa As HE Has POX DNA
(naked)
PARvovirdea
PAPovavirdea
Adenovirdea
(enveloped)
HErpesvirdea
Hepadnavirdea
POXvirdea
6
Q
Treatment of Genital Herpes
A
Doesn’t have any. if you have it, you have it for life.
Symptomatic relief regimen:
Acyclovir 400 mg TID for 5 days (4-3-5)
7
Q
HSV incubation period
A
2-7 days
8
Q
Target or Bull’s eye lesion is specific for
A
Erythema Multiform (HSV1-2)
9
Q
Steven Johnson Syndrome
A
Is Eryhtema Multiform Major (HSV1-2)
-Fever
-Extensive Oral Lesions
-Desquamating lesions
10
Q
Histological feature of CMV
A
Owl’s eye
11
Q
Most commonly available serologic test for measuring antibodies to CMV.
A
ELISA
12
Q
Varicella Zoster Virus Incubation Period
A
1-3 Weeks (7-21 days)
13
Q
CMV incubation period
A
3-12 Weeks
14
Q
Congenital defects associated with CMV
A
IUGR
Microcephaly
Hepatosplenomegaly
Sensory neural hearing loss
15
Q
Most common cause of sensory neural hearing loss
A
CMV
16
Q
Materno fetal transmission rate of CMV
A
40%
17
Q
CMV causes a disease called
A
Mononucleusis Syndrome
18
Q
Most common cause of Infectious mononucleosis
A
Ebstein-Barr Virus
19
Q
HIV primarily infects which cells?
A
CD4 cells
Dendritic cells
Macrophage
20
Q
Perinatal Transmission rates of HIV
A
with treatment <1%
Without treatment =15%
21
Q
Perinatal Transmission rates of HIV
A
with treatment <1%
Without treatment =15%
22
Q
Risk factors of HIV Perinatal transmission
A
High maternal viral load
Low CD4 count
Prolonged rupture membrane
Chorioamnionitis
Co morbidity (HCV, malaria)
Breastfeeding
Preterm birth
23
Q
What disease does rubella cause?
A
German Measles
24
Q
Feto- maternal Transmission Rate of Rubella virus
A
1st trimester = 90%
2nd trimester = 30%
Risk of transmission is decreased after 16 weeks
25
Obligate Aerobes
Pseudomonas
Mycobacterium
Nocardia
26
Facultative Anerobes
E. Coli
Staphylcoccus
Enterococcus
27
Obligate Anerobes
Colistridia
Bacteroids
Prevotella
28
Which one of the following bacteria produces an exotoxin causing 'toxic shock syndrome' associated with tampon usage
Staph aureus
29
Features of Strept. Pneumonia
1. alpha hemolytic strept.
2. G+ve diplococci
3. Optochin sensitive
4. Bile soluble
5. Quellung reaction (spelled capsules)
30
Clinical features of Strept. Pneumonia
MOPS
Meningitis
Otitis media
Pneumonia
Sepsis (in sickle cell disease/ splenic patients)
31
DOC in treating Strept. Pneumonia
Penicillin
then ceftriaxione and Macrolides
32
Features of Staph aureus
1. G+ve cocci
2. Catalase +ve
3. Urease -ve
4. Coagulase +ve
5. Ferments mannitol
33
Clinical features of Staph aureus
Skin infections
Osteomylitis --> septic arthritis
Endocarditis
Toxic shock syn. (with tampon usage)
Food poisoning
Staph scalded skin syndrome SSSS
34
Toxin by Staph aureus causes Toxic shock syndrome
TSST-1 Enterotoxin F (superantigen)
35
Toxin by Staph aureus causes Staph Scalded Skin Syn.
Exfoliate toxin A & B (superantigen)
36
Most common cause of UTI
E.coli
37
Most common cause of UTI in sexually active women
Staph. Saprophyticus
38
Group F streptcocci
Strept. anginosus
39
Group D streptococci
Enterococci
Strept. Bovis
40
Most pathogenic beta hemolytic strept
Strept pyogens GAS
41
GAS is commensal in
Nasopharynx
42
Features of GAS
Has M protein and Hyaluronic acid capsule
Bactricin Sensitive
Catalase negative
produce different endotoxins & extoxins
43
Symptoms of GAS
Pyogenic:
- Pharyngitis
-impetigo
-erysipales
-cellulitis
Immungenic:
-Rhemuatic fever
-Glomerulonephritis
Toxogenix:
-toxic shock-like syn.
- Scarlet fever (strawberry tongue
44
GAS produce three important inflammatory enzymes
1. Hyalorunidase-> degrades hyaluronic acid -> Skin infection
2. Streptokinase (fibrinolysin)
3. DNAse-> degrades DNA in exudates and necrotic tissue
45
GAS produce important toxins
1. Erythrogenic toxin A (pyrogenic toxin A)
2. Streptolysin O
3. Streptolysin S
4. Exotoxin B
46
Scarlet Fever
- Fever
- Flushed Cheeks
- Endometritis
-Strawberry tongue
47
Cause of Necrotizing fasciitis type 2
GAS
48
M Protein virulence factor:
- Fimbrial protein
-Involve in capsule formation
- Anti phagocytic
-Involve in destroying c3 convertas and prevents opsonization by c3b
- Responsible for organ adhesion and invasion
49
What type of hypersensitivity is Rheumatic fever
Type II
50
What type of hypersensitivity is Glomerulonephritis
Type III
51
Which is the single most appropriate treatment of Chlamydia vaginal infection in pregnancy
Erythromycin 500 mg BID/14 days
52
Early onset neonatal infection of GBS
before 7 weeks - presented by neonatal sepsis
53
Late onset neonatal infection of GBS
7 weeks to 3 months - presented by meningitis (capsular serotype III) most common
54
GBS clinical features in neonates
Neonatal Sepsis
Meningitis
Pneumonia
55
GBS clinical features in adults
Endocarditis
Arthritis
Pneumonia
Osteomyelitis
Postpartum endometritis
56
Main predisposing factor of GBS transfer to neonates
Prolonged Rupture of membranes in women who are colonized with the organism
57
Main predisposing factor of GBS in Adults
Diabetes Mellitus
58
risk factors for neonatal GBS
- Preterm Delivery (<37 w)
- Prolonged ROM (>18 before time of delivery)
- Prolonged Labour
-Choriamnionitis
59
Antibiotic Regimen to treat GBS
- Benzylpenicilin G 3 gm IV then 1.5 gm IV/4 hrs until delivery
- Clindamycin 800 mg IV/ 4hrs until delivery
- Erythromycin 500 mg IV/ 6hrs until delivery
60
Most Enterococci species to cause infection
E. faecalis 85-90%
61
How is Enterococci are hardy organisms
They are commensals of normal flora of the colon.
They can grow in hypertonic (6.5%) saline or in bile
They are not killed by Penicillin G
62
Important Risk factors of Enterococci infection
Nosocomaila Infection:
Indwelling urinary Catheter
Urinary tract instrumentation
63
Important Risk factors of Enterococci infection
Nosocomaila Infection:
Indwelling urinary Catheter
Urinary tract instrumentation
64
Treatment of Enterococci infection
synergetic combination of penicillin G and amino glycoside (gentamycin)
65
N. Meningitides has three important virulence factors:
1. Polysaccharride capsule. It is antiphagocytic in nature.
2. The endotoxin of N. Meningitidis is a lipopolysaccharide (LPS). It induces septic shock by causing release of cytokines.
3. IgA protease. It cleaves the IgA antibodies present in respiratory mucosa.
66
Method of transmission of N. Meningitides
The organisms are transmitted by airborne droplets
67
most common cause of meningitis in persons between the ages of 2 and 18 years.
N. Meningitidis
68
What is waterhouse friderichsen syndrome
Is a group of symptoms caused when the adrenal glands fail to function normally. This occurs as a result of bleeding into the glands. Caused by Meningococci
69
Different methods for laboratory diagnosis of N. Meningitidis are
-Gram staining: G-ve bean shaped diplococci
-Culture: grows on blood and chocolate agars
-Oxidase test: Oxidase +ve
-Fermentation tests: ferment maltose & mannitol
-Latex agglutination test: detects capsular polysaccharide in the spinal fluid.
70
features of meningitis caused by N. Meningitidis
1. headache
2. fever
3. neck stiffness
4. photophobia
5. phonophobia
71
N. Gonorrhoeae causes
- gonorrhea
- neonatal conjunctivitis (ophthalmia neonatorum)
- pelvic inflammatory disease (PID).
72
Most important virulence factor of N. gonorrhea
Pili
Piliated gonococci are usually virulent, whereas non piliated strains are avirulent.
73
Different methods for laboratory diagnosis of N. Gonorrhea are
-Gram staining: G-ve bean shaped diplococci
-Culture: grows on Thayar-Martin Agar or Mueller-Hinton agar (chocolate Agar)
-Oxidase test: Oxidase +ve
-Fermentation tests: ferment mannitol {not maltose}
74
Clinical picture of gonorrhea in males
1. Urethritis
2. Prostatitis
3. Epidedimitis
75
PID Clinical Picture
1. Fever
2. Lower Abdominal Pain
3. Abnormal menstrual bleeding
4. Cervical motion tenderness
76
Comiication of PID
1. Infertility
2. Scarring Ectopic pregnancy
3. Peritonitis
4. Violin string adhesions
5. Fitz-Hugh-Kurtis synd.
77
difference between conjunctivitis of gonorrhea and chlamydia
Both Purulent
If infection before 4 days of delivery: gonorrhea
If infection after 5 days of delivery: chlamydia
78
Treatment of Gonorrhea
Ceftriaxone + Azithromycin
79
What sexually transmited disease (STD) is caused by Haemophilus ducreyi?
Chancroid
80
Syphilis caused by which organism
Treponema Pallidum
81
Mode of transmission of Syphilis
1. Acquired (direct contact)
- MSM 35%
- Oral 15%
2. Vertical from mother to fetus
(transplacental passage only occurs when placenta fully developed at 14 weeks)
82
1ry stage of Syphilis
1-3 weeks after infection
Chancer (painless ulcer)
Regional lymphadenopathy
83
2ry stage of Syphilis
6-12 w after infection (4-10 w after chancer appears)
Maculopapular rash
Chondyloma Lata
84
Neurosyphilis features
from 15-30 years of infection
- Ascending aorta (aortitis, aortic aneurysm)
-Endartritis (info. of vasa vasorum
85
Features of early onset congenital syphilis
within 2 years
- IUFD
- Rhagades (linear cracks at the angle of the mouth)
-Hemorrhagic Rhinitis (Bloody snuffles)
86
Features of late onset congenital syphilis
After 2 years
- saber shins
- saddle nose
- hutshingson's disease
-Mulberry molars
87
Syphilis Antigens
1. Group specific antigen (all treponema)
2. Species specific antigen (specific to T. palladium)
3. Cardiolipin (lipoprotein present in spirochetes)
Antibodies appear 4-8 weeks after infection
88
Sexual history in primary syphilis
History of partners for the last 3 months
89
Sexual history in early 2ry and late latent syphilis
History of partners for the last 2 years
90
VDRL to assess syphilis serological activity
>1:8 --> Positive
>1:16 --> Active disease
<1:6 --> doesn't exclude active disease particularly if symptoms are present
91
VDRL to assess response to treatment of syphilis
After treatment with penicillin --> Repeat VDRL after 4 weeks --> 4 folds decrease means treated
92
Donovan bodies' are associated with?
Granuloma inguinale
93
What is the incubation period for Rubella?
12-23 days
94
Chlamydia trachomatis causes
- urogenital infection
- trachoma
- conjunctivitis
- pneumonia
- Lympogranuloma venerium
95
What kind of Organism is chlamydia
Obligate intracellular parasites
96
Chlamydia trachomatis serovars
L1, L2, L3
97
What virus family does HIV belong to?
Retroviridae
98
What kind of organism is Toxoplasma Gondii?
intracellular protozoan
99
What is the most common type of nosocomial infection in uk hospitals?
UTI
100
Which group of viruses cause molluscum contagiosum ?
Pox virus
101
congenital infections is most characteristically associated with fetal hydrops?
Parvovirus-B19
102
What is the causative organism of Toxoplasmosis?
Toxoplasma Gondii
103
which infection is most commonly associated with an increased risk of ectopic pregnancy?
Chlamydia trachomatis
104
What is the primary causative organism in Bacterial Vaginosis?
Gardnerella vaginalis
105
Which kind of organism is Neisseria Gonorrhoeae?
Gram Negative Cocci
106
What stage of syphilis infection is gumma?
tertiary stage
107
What is the causative organism of gas gangrene?
Clostridia perfringens
108
Which species of candida is the most common cause of genital candida infection in pregnancy?
Candida albicans
109
Which group of beta haemolytic streptococci isassociated with chorioamnioitis?
GBS
110
What is the approximate risk of HIV transmission during a single episode of vaginal unprotected sexual intercourse with a known HIV positive person?
0.05%
111
REGARDING URINARY TRACT INFECTIONS, WHICH MICRO-ORGANISM IS MOST LIKELY TO BE ASSOCIATED WITH BLADDER CATHETERISATION?
PSEUDOMONAS AERUGINOSA
112
141. Which of the following cell types lyses cells that have been infected with viruses?
CD8+T CELLS
113
Causative organism of granuloma inguinale
Klebssiella Granulomatous
114
Structure of mycoplasma genitalium
Flask shaped
115
Which HPV causes genital warts
HPV 6 & 11
116
When is the highest risk of maternal-fetal transmission of Toxoplasma gondii
24-26 weeks
117
Percentage of women develop antibodies to human papilloma virus following infection
50-60%
118
Routine antenatal screen is usually for
1. HIV
2. HBV
3. Syphilis
119
Tubal Infertility rate after 1 episode of PID
12%
120
Tubal Infertility rate after 3 episode of PID
50%
121
Mortality rate in patients with Septic shock
60%
122
Prevalence of HIV in the UK obstetric population
2 per 1000 live births
123
GBS Antibiotic Prophylaxis in elective CS
No AB prophylaxis needed in planned CD with no labor and intact membranes
124
Mortality rate of treated disseminated neonatal herpes
30%
125
Percentage of CMV infected infants are symptomatic
10%
126
Leading cause of surgical site infections
Staphylococcus aureus
127
What percentage of HPV infections will be cleared by the host within one year
70%
128
What percentage of HPV infections will be cleared by the host within 2 year
90%
129
Which group of beta hemolytic streptococci is associated with liver abscess formation
Group F: S. anginosus
130
Fetal case mortality rate associated with listeria infection during pregnancy
20-30%
131
What percentage of trichomoniasis cases would you expect to a strawberry cervix
2%
132
HPV Vaccine Gardasil is of what type
Recombinant vaccine of virus-like particles
133
The risk of FVS to babies born to mother who have chickenpox in first 20 weeks of gestations
1-12 weeks = 0.4%
13-20 weeks= 2%
134
Features of fetal varicella syndrome
- hypoplasia of one limb
- cicatricial lesions with a dermatomal distribution
- CNS abnormalities
- Eye abnormalities
135
What percentage of trichomoniasis cases is asymptomatic
50%
136
What percentage of trichomoniasis cases has yellow frothy discharge
20%
[total patients with vaginal discharge 70%]
137
What epithelium cell type lines in the endometrium
Columnar
138
Congenital rubella syndrome
- Cataract
- Bluberry muffin rash
- PDA
- deafness
139
1st line TTT of Listeria
Amoxicillin or Penicillin
140
What is the first line treatment of trichomoniasis
Metronidazole 400 mg TDS 7 days
(HIV +ve 500 mg BD)
141
Most common causative organism of Fitz Hugh Curtis syndrome
Chlamydia trachomatis
142
TTT of toxoplasmosis
W/O fetal infection: Spiramycin
W/ Fetal infection: primethamine, sulfadiazine and folinic acid
143
Incidence of listeriosis in pregnancy
1 per 10,000
144
What are the two major onco proteins associated with high risk HPV
E6 and E7
145
Most common cause of sepsis in puerperium
Genital tract infections (endometritis)
146
Most common causative organism of puerperal sepsis
GAS
147
Which type of cells are clue cells
Epithelial cells
148
Lancefield grouping of streptococci is based on the presence of
Carbohydrate antigen on cell wall
149
What do these signs refer to:
- green vaginal discharge
- erythematous cervix
- perinuclear halo by microscope
Trichomonas vaginalis
150
Organism subunit vaccine
Pertissis
Hepatitis B
Influenza
Neisseria meningitides
151
Which organism colonize copper IUD
Actinomyces species
