Microbiology Flashcards
(154 cards)
1
Q
What are the consequences of toxoplasmosis in pregnancy?
A
1) Microcephaly
2) Hydrocephalus
3) Cerebral calcifications
4) Cerebral palsy
5) Epilepsy
6) Choroidoretinitis
7) Thrombocytopenia.
2
Q
When are fetal consequences most severe in toxoplasmosis?
A
If transmission occurs in first 10 weeks
3
Q
When is there the greatest risk of transmission?
A
Further into the pregnancy, however although the transmission rate increases, the severity decreases with greater gestation
4
Q
What does HBsAG show?
A
Acute infection
5
Q
What does HBeAG show?
A
Viral replication, and therefore high infectivity
6
Q
Anti-HBc shows what?
A
Previous or ongoing infection
7
Q
Anti-HbsAb shows what?
A
Either vaccination or immunity following previous infection
8
Q
What is the most common congenital infection?
A
CMV
9
Q
What proportion of children with congenital CMV infection are a) symptomatic at birth? b) symptomatic in later life?
A
a) 10-15%
b) 10-15%
10
Q
What infection causes strawberry cervix?
A
TV
11
Q
What is the drug combination used in TB?
A
Rifampicin + Isoniazid + Pyrazinamide + Ethambutol
12
Q
What are the S/Es of rifampicin?
A
Orange urine and tears
Hepatotoxicity
13
Q
What are the S/Es of isoniazid?
A
Hepatotoxicity
Peripheral neuropathy
14
Q
What are the S/Es of pyrazinamide?
A
Hepatotoxicity
Gout
15
Q
What are the S/Es of ethambutol?
A
Optic neuritis
16
Q
What are the polymicrobial causes of endometritis?
A
Ureaplasma
Gardnerella
Group B Strep
17
Q
What are the alpha haemolytic streps?
A
Strep pneumonia
Strep viridans
18
Q
Which type of bacteria produce endotoxins?
A
Gram -ve ONLY. Only gram -ve can produce endotoxins, whilst both gram +ve and gram -ve bacteria can produce exotoxins
19
Q
What is CMV caused by?
A
Human herpes virus 5
20
Q
What are the gram +ve bacilli?
A
Listerias
Clostridiums
Actinomyces’
Mycobacteriums
21
Q
What are the gram +ve cocci?
A
Staphylococcus’
Streptococcus’
Enterococcus’
22
Q
What are the gram -ve bacilli?
A
Escherichias Enterobacters Klebsiellas Salmonellas Shigellas Campylobacters Legionellas
23
Q
What are the gram -ve cocci?
A
Neisserias
24
Q
Which bacteria is associated with sulphur granules on coils?
A
Actinomyces israelis
25
What does the gardasil vaccine consist of?
HPV 6/11/16/18
26
What proportion of HPV-related cancer is caused by 16 and 18?
70%
27
What type of vaccine is gardasil?
Vaccine of virus-like particles (VLPs)
28
What oncoproteins are associated with HPV?
E6 and E7
29
What tumour suppressor protein is inactivated by E6?
p53
30
What tumour suppressor protein is inactivated by E7?
pRB
31
What are the ssRNA viruses?
Hep A/C/D/E
Rubella
HIV
32
What are the dsRNA viruses?
Rotavirus
33
What are the ssDNA viruses?
Parvovirus B19
34
What are the dsDNA viruses?
```
Hep B
CMV
HSV
HPV
EBV
VZV
```
35
What is group A beta haemolytic bacteria?
Streptococcus pyogenes
36
What is a group B beta haemolytic bacteria?
Streptococcus agalactia
37
What is a group C beta haemolytic bacteria?
Streptococcis dysgalactiae
38
What is a group D beta haemolytic bacteria?
Re-classified as enterococcus
39
What is a group F beta haemolytic bacteria?
Streptococcus anginosus
40
What is a group G beta haemolytic bacteria?
No specific name - just group G streptococcus
41
What does group G streptococcus cause?
Toxic shock
Necrotising fasciitis
Vaginitis
42
What does Streptococcus anginosus cause?
Liver abscess
43
What does enterococcus cause?
Colitis
| Endocarditis
44
What does Streptococcis dysgalactiae cause?
Pharyngitis
Endocarditis
Toxic shock
Necrotising fasciitis
45
What does Streptococcus agalactia cause?
GBS disease of the newborn
Chorioamnioitis
Endometritis
46
What does Streptococcus pyogenes?
```
Scarlet fever
Rheumatic fever
Tonsilitis/pharyngitis
Toxic shock
Necrotising fasciitis
```
47
What is the most common causative organism of cellulitis?
Streptococcus pyogenes
48
What is the most common causative organism of skin/superficial wound/SSI?
Staphylococcus aureus
49
What are the treatments for anogenital warts?
1) Podophylline paint
2) 5-FU
3) Trichloracetic acid
4) Liquid nitrogen cryotherapy
5) Imiquimod 5% cream
6) LASER
50
What are the treatments for anogenital warts not suitable in pregnancy?
Podophylline paint and 5-FU
51
What is the cause of gas gangrene?
Clostridia perfringens
52
How is toxoplasmosis treated?
Spiromycin
53
How is toxoplasmosis diagnosed?
PCR/immunoglobulins, or ring-enhancing lesions on MRI/CT
54
When are Abx not needed in a GBS +ve pregnancy?
In a planned elective section, in the absence of labour where the membranes are intact
55
What is the FVS risk in the first 12 weeks of gestation?
0.4%
56
What is the FVS risk in weeks 13-20/40?
2%
57
What are the consequences of FVS?
1) hypoplasia of 1 limb
2) CNS abnormalities
2) Eye abnormalities
58
What is the incidence of listeriosis in pregnancy?
12/100,00. It is 20x more likely in pregnancy
59
How is listeria treated?
2-3/52 amoxicillin
60
What does listeriosis in pregnancy cause?
1) Chorioamnionitis
2) Placental necrosis
3) Granuloma formation
61
What is the fetal mortality of listeria?
20-30%
62
What infection is blueberry muffin rash associated with?
Congenital rubella syndrome
63
What is the HIV testing regime of formula fed infants?
During hospital admission
2 weeks post cessation of prophylaxis (age 6 weeks)
2 months post cessation (age 12 weeks)
HIV Ab testing for seroreversion at 18 months
64
When should children breast-fed by HIV mothers be tested?
As above, but tests additionally every month.
65
What is the incubation of chickenpox?
14 (10-21)
66
What is the incubation of rubella?
14 (12-23)
67
What is the incubation of influenza?
1-3
68
What is the incubation of parvovirus (fifth disease)?
4-20
69
What is the incubation of CMV?
3-12/52
70
What is the risk of congenital CMV with primary infection in pregnancy?
30-40%
71
What is the risk of congenital CMV with recurrent infection in pregnancy?
1-2%
72
Which organism causes lymphogranuloma venereum?
Chlamydia trachomatis L1–L3
73
Which organism causes ocular trachoma?
Chlamydia trachomatis A–C
74
What type of fungus is Candida albicans?
Yeast-like fungus
75
How does listeria monocytogenes circumvent the immune system?
It is an intracellular pathogen and 'hides' within phagocytic cells
76
What is the route through which CMV is most commonly transmitted?
Breastfeeding
77
What proportion of people whom are admitted to hospital develop and hospital-acquired infection?
10%
78
What pressure do theatre air systems generate and why?
Generates positive air pressure in order to draw air away from the patient so that it may be filtered for airborne infections
79
How are gram -ve organisms usually spread?
Aerosol route
80
What may cause sudden deterioration in a Hep B infection?
Delta-virus super-infection, esp. in IVDU's
81
Which microorganism most commonly causes catheter-associated UTIs?
Pseudomonas
82
What is leptospirosis also called?
Well's disease. It is caused by leptospira which is a spirochaete
83
What are the zoonoses?
```
Anthrax (cattle, goats)
Listeriosis (pets)
Leptospirosis (rats)
Toxocara (cats)
Toxoplasmosis (dogs)
Tapeworms (dogs)
Brucella (sheep)
TB (cattle)
```
84
What type of organism is actinomyces israelii?
Gram positive, cast-forming, non-acid-fast, non-spore-forming anaerobic bacillus
85
How is actinomyces israelii treated?
Penicillins/cephalosporins. In those that are penicillin allergic, tetracyclines may be used
86
What are the notifiable diseases?
```
Food poisoning
Haemolytic uraemic syndrome
Meningitis
Meningococcal septicaemia
Rubella
Malaria
Mumps
Measles
TB
```
87
What bacteria can cause osteomyelitis?
Staphylococcus
Haemophilus influenzae
Salmonella
P. aeruginosa
88
What happens when blood agar exposed to staph aureus?
Haemolysis
89
What is the mechanism of action of ciprofloxacin?
Interferes with DNA synthesis by disrupting the function of DNA gyrase
90
With what stain is toxoplasmosis identified?
Giemsa stain
91
What is the mechanism of action of glycopeptides (for example, vancomycin)?
Inhibit cell wall synthesis through steric hindrance of peptidoglycans
92
Which organism causes lymphogranuloma venereum?
Chlamydia
93
What family of viruses does EBV belong to?
Herpes virus
94
What are the predominant organisms of the vagina?
Lactobacilli
95
What is the pH of the vagina during a woman reproductive life?
3.5-4.5
96
What is the pH of the vagina after menopause?
7 (the bacterial flora become more like the skin again)
97
What causes the cuboidal epithelium lining the vagina of a child to turn into the stratified squamous epithelium found in the vagina of a woman of reproductive years?
Puberty and the influence of oestrogen
98
What are the constituents of physiological discharge?
1. Desquamated epithelial cells
2. Mucus from the cervical glands
3. Bacteria - mainly lactobacilli
4. Transudate from through the vaginal wall (major constituent)
99
What are the types of vaginal candidia?
C. albicans - 80% of affected women
| C glabrata, C krusei, C tropicalis - remaining 20% of affected women
100
What factors predispose to vaginal candidiasis?
1. Immunosuppression
2. DM
3. Vaginal douching
4. Increased oestrogen levels - e.g. pregnancy
5. Broad spec Abx therapy
6. Skin conditions
101
What treatment should be given fro candidiasis in pregnancy?
Clotrimazole 100mg/day pessaries for 7/7. Oral therapies NOT recommended
102
What is the pH of the vagina in BV?
4.5-7.0 due to the loss of lactobacilli
103
What are the Amsel criteria for diagnosis of BV?
1) Fishy smell
2) pH>4.5
3) Clue cells
4) Characteristic discharge O/E
104
What are the complications of BV?
1) Increased risk of second-trimester miscarriage
| 2) Increased risk of preterm delivery
105
What medium should be used for culture of TV?
Feinberg-Whittington medium
106
Which serovars of chlamydia cause LGV?
L1-L3
107
What is the 'gold standard' method of diagnosis of PID?
Laparoscopy
108
What is Reiter syndrome?
Disseminated infection with chlamydia trachomatis resulting in asymmetrical oligoarthritis of the large joints of the lower limbs, uveitis and a rash
109
Which is HLA is associated with Reiter syndrome?
HLA B27
110
What can chlamydia and/or gonorrhoea cause in newborns?
Opthalmia neonatorum - causes keratoconjunctivitis, corneal scarring and blindness. They may also cause pneumonitis in the first few months of life and so newborns with opthalmia neonatorum should recieve systemic therapy with erythromycin
111
What causes yaws?
Treponema pallidum pertenue
112
What causes pinta?
Treponema pallidum carateum
113
What causes bejel (endemic syphillis)?
Treponema pallidum endemicum
114
Over what period does a chancre appear in syphillis?
3-6/52
115
What are the conseqences of syphillis for a neonate?
Fetal death
Eight-nerve deafness
Interstitial keratitis
Mulberry teeth
116
What may be seen on dark-field microscopy in syphillis?
Spirochaetes
117
What is the Jarisch-Herxheimer reaction?
An exacerbation in symptoms +/- fever that may occur 24 hours after the start of treatment of syphillis. It is due to the release of proinflammatory cytokines following death of organisms.
This reaction may induce preterm labour in a woman with a high organism load when treated in pregnancy.
118
What disease is 'groove sign' associated with?
Lymphogranuloma venereum (LGV) - occurs when the enlargement of LNs in the groin region form buboes which are then compressed by the inguinal ligament
119
What infection causes chancroid?
Haemophilus ducreyi
120
What is more common - HIV1 or HIV2?
HIV1
121
How does HIV gain access to a cell?
The viral outer membrane protein gp120 binds to the CD4 receptors present on T lymphocytes, macrophages etc.
122
What is the proportion of vertical transmission of HIV if no intervention is made?
25-40% - mainly through transmission from breastfeeding
123
What should happen if varicella develops at the end of pregnancy?
It may be that the fetus is exposed to infection without the benefit of passive maternal antibodies. Therefore, if maternal infection occurs 7 days before or after pregnancy VZIG should be given to prevent severe infection
124
What proportion of pregnancies does CMV affect?
0.5%
125
How is transmission rate and severity related in CMV?
Transmission rate increases the further along the pregnancy, but severity decreases the further along the infection is acquired
126
What are the possible USS features of CMV?
1) Ventriculomegaly
2) Pseudocysts
3) Microcephaly
4) Intra-cranial calcification
5) Abnormalities of cerebellum
6) Echogenic bowel
7) IUGR
8) Splenomegaly
9) Cardiomegaly/pericardial effusion
10) Hydrops
127
What are the only infections to be routinely screened for at booking?
HIV
Hep B
Rubella
Syphillis
128
How do you tell the difference between gram +ve and gram -ve bacteria?
Gram +ve bacteria retain the colour violet dye
| Gram -ve bacteria do not retain the violet dye's colour and instead turn pink with the addition of a counter stain
129
What are obligate aerobes?
Require the presence of O2 to grow
130
What are facultative anaerobes?
Can tolerate aerobic and anaerobic conditions
131
What are obligate anaerobes?
Require the exclusion of O2 to grow
132
What type of bacteria is listeria?
Gram +ve, rods, facultative anaerobes
133
What are the 2 types of listeriosis?
Early - occurs within 2 days postpartum, they usually present septic with disseminated organ involvement. mortality is 60%
Late - occurs more than 5 days postpartum, usually as meningitis
134
What are enterobacteriaceae?
Gram -ve rods that ferment glucose - 2 types, gut commensals and overt bacteria
135
What are the enterobacteriaceae gut commensals?
```
E.coli
Klebsiellas
Proteus
Enterobacter
Citrobacter
```
136
What are the enterobacteriaceae overt bacteria?
Salmonellas
Shigella
Campylobacter
137
What are the complications of severe malaria?
1. Severe anaemia
2. Acute pulmonary oedema
3. Hypoglycaemia
4. Cerebral malaria - reduced GCS and seizures
5. DIC
6. Acute renal failure - blackwater fever due to intravascular haemolysis
138
What haematological characteristic is associated with increased incidence of malaria?
Duffy antigen
139
Are bacteria visible using light microscopy?
Yes
140
What are the mechanisms of bacterial antimicrobial resistance?
1. Drug inactivation
2. Alteration of drug target site
3. Alternation in the bacteria's metabolic pathway
4. Fibronectin coast
5. IgA cleaving protease
141
How many of the Amsel criteria are required for diagnosis of BV?
3/4
142
What are Argyll Robertson pupils?
Small, irregularly shaped, difficult to dilate pupils, that may occur as a result of neurosyphillis
143
What is mycoplasma hominis?
May be a primary or co-pathogen in PID, or a co-pathogen in chorioamnionitis
144
Which types of chlamydia causes genital chlamydia?
D-K
145
What is the serology process for diagnosing syphillis?
IgM/FTA-ABS --> IgG --> TPPA --> VDRL
146
How many organism are required to develop a wound infection?
10 to power 5 (usually), 10 to power 3 in the presence of a foreign body
147
What is the difference between type 1 and type 2 necrotising fascitis?
Type 1 = associated with surgery/diabetes. Polymicrobial
| Type 2 = due to group A streptococcus
148
What culture does chlamydia grow on?
McCoy's culture
149
What are the different types of, and examples of, fungal groups?
1. Mould - e.g. aspergillus
2. True yeast - e.g cryptococcus
3. Yeast-like - e.g. candida
4. Dimorphic - e.g. histoplasma
150
What are the 2 types of protozoa?
1. Protozoa
| 2. Helminths
151
What are the 3 groups of helminths?
1. Fluke
2. Tape
3. Worm
152
At what CD4 count foes AIDS occur?
<200
153
What proportion of Hep B feto-maternal transmissions occur in the 3rd trimester?
90%
154
What is the Hep B feto-maternal transmission rate when mother is HBeAg positive?
90%
