Microbiology and Infectious Disease Flashcards
1
Q
define pathogen
A
an organism that is capable of causing disease
2
Q
define commensal
A
organism which colonises the host but does not cause disease in normal circumstances
3
Q
define opportunist pathogen
A
microbe that only causes disease if host defences are compromised
4
Q
define virulence/pathogenicity
A
the degree to which a given organism is pathogenic
5
Q
define asymptomatic carriage
A
when a pathogen is carried harmlessly at a tissue site where it causes no disease
6
Q
describe the structure of a Gram negative bacterial cell envelope
A
inner cell membrane, thin peptidoglycan layer, outer cell membrane, lipopolysaccharide layer, outer capsule.
7
Q
describe the structure of a Gram positive bacterial cell envelope
A
thick layer of peptidoglycan between the outer capsule + inner cell membrane.
8
Q
what is a bacterial endotoxin? describe features
A
a component of the cell wall that is released when the bacteria is damaged.
less specific actions than an exotoxin e.g. septic shock
9
Q
what is a bacterial exotoxin? describe features
A
mainly excreted by Gram +ve bacteria. actively secreted toxins with specific actions.
10
Q
how might bacterial genes be transferred between bacteria?
A
transformation e.g. via plasmid.
transduction e.g. via phage.
conjugation e.g. via sex pilus.
11
Q
describe the process of Gram staining
A
- heat fix sample to slide
- add methyl violet (blue/purple)
- add iodine - fixes methyl violet to gram +ve samples
- add alcohol to decolorize Gram -ve samples
- counterstain with basic fuchsin (red)
12
Q
what is the normal habitat of staphylococcus spp?
A
nose and skin
13
Q
how is S aureus spread?
A
aerosol and touch
14
Q
what agar is used to grow enterobacteria?
A
MacConkey - bile salts, lactose, pH indicator
15
Q
How do you distinguish Salmonella/Shigella from E coli on a MacConkey-lactose agar?
A
E.coli = pink, as it is lactose fermenting Shigella/salmonella = yellow, non-lactose fermenting
16
Q
how would you distinguish between Salmonella and Shigella?
A
serology, as both are non-lactose fermenting so appear the same on MacConkey agar
17
Q
what are the main infections caused by pathogenic E coli strains?
A
wound infections (surgical). UTIs. gastroenteritis. travellers' diarrhoea. bacteraemia. meningitis.
18
Q
what 3 infections are caused by salmonella?
A
- gastroenteritis - food poisoning (localised infection)
- enteric fever - typhoid (systemic infection)
- bacteraemia - uncommon
19
Q
what agar must H influenzae be grown on and why?
A
fastidious - requires haem and NAD - will not grow on blood agar, only chocolate agar (blood agar that has been heated so haem and NAD are released by RBCs).
non-motile.
20
Q
describe the main features of Legionella pneumophila and Legionnaires’ disease
A
seen in immunocompromised (elderly, alcoholics, smokers).
severe.
culture on charcoal agar.
found in man-made aquatic environments - replicates within freshwater protozoa.
can infect alveolar macrophages.
induces phagocytosis.
21
Q
what are the clinical features of an infection with campylobacter?
A
mild to severe diarrhoea, often with blood.
self-limiting (up to 1 wk).
campylobacter shed in faeces for 3wks.
22
Q
describe the features of bacteroides? where are they typically found as commensals?
A
non-motile rods.
strict anaerobes.
commensal flora of large intestine (also commensal in vagina/cervix).
23
Q
what shape are bacteroides?
A
bacilli
24
Q
what shape are spirochaetes?
A
spiral/helical
25
describe the cell wall of fungi and how it stains?
rigid. polysaccharides and chitin.
stain with Gomorra methenamine silver, and periodic acid-Schiff.
lack a capsule.
26
describe the features of yeasts
unicellular.
round/oval.
asexual - reproduce by budding.
27
what are dimorphic fungi?
fungi which grow as yeasts in tissue, but as moulds in-vitro.
28
describe the features of moulds
composed of tubular structures (hyphae).
grow by longitudinal extension and branching - interwoven mycelium.
reproduce by spore formation (sexual/asexual).
29
what type of fungi is candida albicans?
yeast
30
give some examples of moulds
aspergillus spp.,
fusarium spp.
mucoraceous moulds.
dark-walled fungi.
31
what are the 3 types of fungal infection?
1. superficial mycoses
2. subcutaneous mycoses
3. systemic mycoses
32
name some common sites for superficial mycoses
skin, hair, nails, mucous membranes
33
what are the two main kinds of infection seen in superficial mycoses?
ringworm.
| yeast infections.
34
what pathogens cause ringworm (dermatophytosis, tinea - athletes foot, swimmers crotch etc)?
tricophyton spp.
microsporum spp.
epidermophyton spp.
35
describe the transmission of ringworm infections
direct or indirect transfer of infected keratin - e.g. communal bathing facilities.
36
describe the different types of aspergillus infection
1. invasive aspergillosis - neutropaenic patients. treat with amphotericin.
2. allergic aspergillosis - ABPA
3. aspergilloma - fungus ball in pre-existing cavity of lung.
37
describe the basic idea behind the treatment of fungal infections, and give examples of drugs used.
```
use drugs that target sterols in their cell membranes.
topical - nystatin, ketoconazole.
systemic:
oral - fluconazole/other azoles
parenteral - amphotericin.
```
38
give some examples of mycobacteria of medical importance, and the diseases they cause
```
M. tuberculosis = TB
M. leprae = leprosy
M. kansaii = chronic lung infection
M. marinum = fish tank granuloma
M. ulcerans = buruli ulcer
```
39
why will immunocompromised patients show disseminated mycobacterial disease, instead of characteristic granulomas?
they don't have enough T cell function to form granulomatas
40
describe the microbiological features of mycobacteria
aerobic, non-spore forming, non-motile bacilli.
cell walls contain a lot of high molecular weight lipids - weakly gram-positive/colourless.
slow growing.
41
what does the thick lipid coating of mycobacteria allow them to do?
survive inside macrophages, even in low pH environment
42
what are the key cell wall components of mycobacteria?
mycolic acids.
| lipoarabinomannan
43
describe Koch's postulates for a disease to be defined as caused by bacteria (/mycobacteria etc)
1. bacteria should be found in all people with disease
2. bacteria should be isolated from infected lesions
3. a pure culture inoculated into a susceptible person should produce disease symptoms
4. same bacteria should then be isolated from that individual
44
what stain is used for mycobacteria and why?
Ziehl-Neelsen stain for acid fast bacilli - high lipid content in cell wall makes mycobacteria resistant to Gram stain
45
what type of granuloma is typically seen in TB?
caseating
46
what are the main principles of mycobacterial treatment?
1. slowly replicating bacteria - so need prolonged treatment
2. multiple drug combinations to combat resistance
3. compliance is essential - directly observe therapy used
47
describe the standard drug regime for tuberculosis
isoniazid, rifampicin, pyrazinamide and ethambutol for 2mths.
then isoniazid and rifampicin for 4 further months.
48
what makes up the primary complex of primary TB?
granuloma + lymphatics + lymph node
49
where in the lung are tuberculosis bacilli most likely to form a granuloma and why?
apex - there is more air and less blood supply, so fewer defending WBCs to fight
50
what is latent TB?
cell-mediated immune response from T cells manages to contain primary infection, but it persists.
no clinical disease (normal CXR).
51
what is pulmonary TB?
follows after primary disease, or after latent reactivation.
| necrosis in lesion. caseous material coughed up, leaving cavity. TB may spread in lung causing other lesions.
52
where, apart from the lungs, may TB spread?
```
GU TB
peritoneal TB
TB meningitis
widespread = miliary TB.
pleural TB
bone and joint TB
```
53
what are the three groups of helminths?
1. nematodes (round worms)
2. trematodes (flatworms, flukes)
3. cestodes (tapeworms)
54
what do adult worms need before they can reproduce?
a period of development outside the body
55
what is the "pre-patent" period in relation to helminth disease?
the interval between infection and the appearance of eggs in the stool
56
how are intestinal nematodes transmitted?
faecal-oral route.
| transmitted from person to person via eggs/larvae - these are only infectious after a period of development in the soil.
57
what organism causes pinworm/threadworm? what is the pre-patent period?
enterobius vermicularis
40d.
v common in UK!
58
describe the lifecycle of enterobius vermicularis (pinworm/threadworm)
1. adult is resident in large bowel
2. female emerges from anus at night to lay eggs on perineum
3. eggs are infectious after 4hrs, ingested by next host
59
what are the clinical features of pinworm/threadworm?
1. pruritis ani
2. appendicitis
3. vaginal penetration - endometriosis, salpingitis, infertility
60
how would you diagnose pinworm/threadworm?
microscopy of sellotape strip from perianal region
61
what is the general way to diagnose worms?
stool microscopy for eggs
62
what drug is used to treat a lot of worm infections? available in pharmacies for threadworm
Mebendazole
63
what causes schistosomiasis?
Schistosoma - an adult fluke. penetrate skin while swimming, mature in abdominal cavity.
64
what is schistosomiasis (katayama fever)? what are the clinical features?
initial immune-complex mediated illness 2-4wks after exposure.
fever; urticaria; eosinophilia; diarrhoea; hepatomegaly; splenomegaly; cough and wheeze; cachexia.
65
what are protozoa?
single-celled eukaryotes.
| consume bacteria, algae, microfungi
66
what are the two main stages in the general life cycle of protozoa?
proliferative TROPHOZOITE stage - feed and reproduce.
| dormant CYST stage - can survive outside host.
67
what are the 5 major groups that protozoa are divided into?
1. flagellates
2. amoebae
3. cilliates
4. microsporidia
5. sporozoa
68
what are the 4 species of plasmodia that cause human disease?
P. falciparum
P. ovale
P. vivax
P. malariae
69
how is malaria transmitted?
bite of female Anopheles mosquitoes
70
how does the Anopheles mosquito become affected?
feeding from infected human. then they are infected for life (3-4wks). night-biting. bite indoors. lifecycle depends on water (to lay eggs)
71
describe the basic stages of the plasmodia lifecycle
in human host has exo-erythrotic cycle (in liver), and erythrotic cycle (in blood). (P ovale/vivax also have hypnozoite stage - lie dormant).
matures in RBCs.
taken up from blood into female anopheles - sporogonic cycle.
72
describe the pathogenesis of falciparum malaria
fatal.
parasite matures in RBCs - 'knobs' on RBC surface.
bind to receptors on endothelial cells in capillaries + venules.
sequestration in small vessels.
obstruction of microcirculation - tissue hypoxia.
73
what are the acute clinical features common to all 4 species of malaria?
FEVER.
chills and sweats; headache; myalgia; fatigue; nausea and vomiting; diarrhoea.
anaemia; jaundice; hepatosplenomegaly; 'black water fever'
74
describe the clinical features of P falciparum malaria in adults
coma; ARDS; hypoglycaemia; renal failure (hypovolaemia, microvascular blockade).
SHOCK.
75
describe the clinical features of P falciparum malaria in children
non-specific - stop crying/playing/eating.
tachypnoea.
anaemia.
hypoglycaemia.
cerebral malaria can cause encephalopathy/coma - raised ICP, varied presentation - rule out meningitis.
76
how is malaria diagnosed?
thick AND thin blood films - 3 separate films at different times of day, examined under light microscopy.
77
how do you treat complicated falciparum malaria?
IV artesunate or IV quinine
78
how do you treat uncomplicated falciparum malaria?
oral riamet or oral quinine (±doxycycline)
79
how do you treat non-falciparum malaria?
oral chloroquine
80
describe the stages of viral replication
1. attachement
2. cell entry - only viral 'core' enters host cytoplasm
3. interaction with host cells - use cell materials for their replication etc
4. replication
5. assembly - may occur in nucleus/cytoplasm or at cell membrane
6. release - by lysis of cell, or by exocytosis
81
list the different ways in which viruses can cause disease
1. direct destruction of host cells
2. modification of host cell structure/function
3. immuno-pathological damage
4. damage through cell proliferation/immortalisation
5. evasion of host defences
82
what determines the defence mechanism employed against bacterial infection?
no. organisms/virulence.
low = phagocytes active
high = immune response
83
what types of immunoglobulin are produced in response to worm infection?
IgG and IgE
84
what is the most widely used antiviral agent? what is it's mode of action?
aciclovir
| nucleoside analogue
85
how do nucleoside analogue antiviral agents work?
phosphorylated within cells to an active triphosphate and inhibit viral DNA synthesis
86
what is septicaemia?
"blood poisoning" - when an infection is found in the circulating blood
87
what are "notifiable diseases"? who should be notified?
diseases/infections/conditions that are specifically listed as notifiable.
local health authorities/Public Health England
88
define "anti-microbial"
agents produced by microorganisms that kill or inhibit the growth of other micro-organisms in high-dilution
89
what is the target site of beta lactams?
cell wall - inhibition of cell wall synthesis.
| include penicillins, carbapenems and cephalosporins
90
give examples of antibiotics that work by interference with nucleic acid synthesis/function
metronidazole
| rifampicin
91
how do metronidazole/rifampicin work?
interfere with nucleic acid synthesis or function
92
how do fluoroquinolones work?
inhibit DNA gyrase
93
what types of antibiotics work by inhibiting ribosomal activity and protein synthesis?
aminoglycosides.
tetracyclines.
macrolides.
chloramphenicol.
94
what is the difference between bacteriostatic and bactericidal bacteria?
```
bacteriostatic = prevent growth of bacteria.
bactericial = kills the bacteria
```
95
what are the two major determinants of anti bacterial effect
concentration and time that the antimicrobial remains on binding sites
96
what antibiotics put the patient at risk of C diff? (the 5Cs of C diff)
Ciprofloxacin; Clindamycin; Cephalosporins; Co-amoxiclav; Carbapenems
97
what are 4 ways a bacteria may resist an antimicrobial?
1. target site mutation
2. destruction/inactivation of antimicrobial
3. prevent antimicrobial access
4. remove antimicrobial from bacteria
98
how does beta lactamase confer resistance to penicillins and cephalosporins?
beta lactam ring is hydrolysed by this bacterial enzyme. antimicrobial is now unable to bind to the bacteria.
99
give some examples of carbapenems and their uses
imipenem, meropenem, ertapenem.
| broad spectrum - severe hospital acquired infections.
100
give some examples of cephalosporins
cefradine
cefuroxime
cefotaxime
101
give examples of glycopeptides, and how they are used
vancomycin , teicoplanin.
gram +ve agents.
IV only.
reserved for serious/resistant gram +ve, e.g. MRSA
102
how does chloramphenicol work? how is it used?
it's a protein synthesis inhibitor.
very broad spectrum (except pseudomonas).
toxicity - little used today.
103
give examples of macrolides, and what they are used for
erythromycin, clarithromycin.
| good for staph/strep. alternatives to penicillins. no gram-ve cover.
104
what type of antibiotic is clindamycin? what is it used for?
lincosamides.
| active against staph, strep and anaerobes
105
give examples of aminoglycosides and what they are used for
gentamicin, tobramycin.
| enterobacteriaceae, pseudomonas and staphylococci.
106
what type of antibiotic is ciprofloxacin? what is it used for?
quinolones.
| used against enterobacteriaceae, pseudomonas and staph.
107
what types of organism is metronidazole active against?
anaerobic.
| bacteria and protozoa.
108
what does the catalase test differentiate between?
staphylococci - catalase +ve
| strep and enterococci - catalase -ve
109
what does the coagulase test differentiate between?
staph areus - coagulase +ve
| other staph - coagulase -ve
110
is staph aureus coagulase negative or positive?
positive
111
what does the oxidase test aim to identify?
oxidase positive bacteria - pseudomonas spp. and neisseria spp.
112
what does the optochin test do?
differentiates Strep pneumoniae from other alpa haemolytic strep.
strep pneumoniae shows a zone of inhibition around the optochin disc
113
What types of bacteria form red/pink colonies on MacConkey agar?
E coli and Klebsiella - lactose fermenting
114
What types of bacteria form a clear colony on MacConkey agar?
Salmonella, shigella, pseudomonas - lactose non fermenting
115
what type of agar differentiates between alpha and beta haemolytic strep?
blood agar
116
how do you identify alpha haemolytic strep (strep viridans) on blood agar?
green pigment due to partial breakdown of blood
117
how do you identify beta haemolytic strep on blood agar?
clear zones around the colonies - complete breakdown of blood
118
what is Lancefield grouping?
differentiates between beta haemolytic Strep spp. by detecting surface antigens
119
which bacteria are in Lancefield groups A, B and D
```
A = strep pyogenes
B = strep agalactiae
D = enterococci
```
120
what are the 6 key Gram +ve staining bacterial groups?
| remember - Sexy Students Can Look Bad Come morning
```
Streptococcus
Staphylococcus
Corynebacterium
Listeria
Bacillus
Clostridium
```
121
are the 6 key groups of Gram +ve bacteria aerobic or anaerobic?
aerobic, apart from Clostridium spp which are anearobes
122
describe the key features of streptococcus spp
chains or diplococci.
gram +ve.
catalase negative.
aerobic.
123
describe the features of strep pneumoniae and what diseases it can cause
gram +ve diplococci. alpha haemolytic. droplet transmission.
| community-acquired pneumonia, sinusitis, bacterial meningitis.
124
what antibiotics would be given to treat strep pneumoniae infection?
penicillin or erythromycin
125
what diseases are caused by alpha haemolytic strep (strep viridans)
bacterial endocarditis + dental caries.
126
how would you treat an alpha haemolytic strep infection?
penicillin/amoxicillin (erythromycin if allergic).
| bacterial endocarditis - penicillin and gentomycin.
127
give the features of strep pyogenes, and the diseases it causes?
group A beta-haemolytic.
transmission is airborne and hands.
cellulitis, necrotising fasciitis, pharyngitis (strep throat), tonsillitis etc
128
what are the features of enterococcus spp and what diseases do they cause?
group D, non-haemolytic, MacConkey growth. GI tract commensal.
infective endocarditis, UTIs, would infections, IV catheter infections.
129
how would you treat an enterococcus infection?
```
pencillin/vancomycin.
serious infection (e.g. IE) - penicillin/vancomycin + getamicin
```
130
describe the key features of staphylococcus spp.
cocci in clumps, Gram +ve.
| catalase positive. coagulase used to differentiate staph aureus (+ve) from the others. aerobic.
131
name two coagulase -ve staphylococcus spp.
staph epidermidis
| staph saprophyticus
132
give some diseases caused by staph aureus
```
Impetigo, cellulitis, wound infection.
osteomyelitis, septic arthritis.
conjunctivitis.
bacterial endocarditis (in IVDU)
pneumonia.
```
133
how would you treat a staph aureus infection?
flucloxicillin.
| MethicillinRSA isn't sensitive to flucloxacillin - use vancomycin instead.
134
give a disease caused by staph saprophyticus and its treatment?
UTI in sexually active young women.
| trimethoprim, flucloxacillin.
135
what is the important species of Corynebacterium? how is it spread? what disease does it cause?
Corynebacterium diphtheriae.
droplet spread.
diphtheria.
136
how would you treat diphtheria?
erythromycin.
| diphtheria antitoxin.
137
are Clostridium spp aerobic or anaerobic?
anaerobic
138
what bacteria causes tetanus? how is it spread? how would you treat it?
clostridium tetani.
spore-forming - spores enter open wounds.
human tetanus Ig + benzodiazepines.
139
what disease does C difficile cause? how does it spread?
transmission = spores via faecal-oral route.
| causes pseudomembranous colitis - diarrhoea following antibiotic therapy.
140
how would you treat C diff diarrhoea?
vancomycin
141
what are the 6 important Gram -ve bacterial groups?
```
Neisseria
Coliforms (also Enterobacteriaceae)
Parvobacteria
Helicobacter
Vibrio
Pseudomonas
```
142
Are the key Gram -ve bacterial groups aerobic or anaerobic?
aerobic
143
describe the features of Neisseria spp.
diplococci. gram -ve. oxidase positive. aerobic.
144
Neisseria meningitidis - give its transmission, diseases caused and treatment
transmission is by droplets/direct mucosal contact.
Causes meningitis and septicaemia (with purpuric skin rash).
treatment - benzylpenicillin or cefotaxime.
145
what disease does Neisseria gonorrhoea cause? transmission? treatment?
gonorrhoea. (opthalmia neonatorum, Reiter's syndrome).
transmission is direct mucosal contact.
treatment = ciprofloxacin or cefixime.
146
List the coliforms (/enterobacteriaceae) according to colour on MacConkey agar
red/pink colony = E coli and Klebsiella penumoniae.
| clear colony = Salmonella typhi, paratyphi (A, B, C) and enteritidis
147
E coli: transmission? diseases caused?
faecal-oral.
| diarrhoea. UTIs, hospital-acquired pneumonia.
148
Klebsiella pneumoniae: diseases caused? treatment?
hospital acquired pneumonia. UTIs.
| cephalosporins.
149
what diseases do Salmonella typhi and paratyphi cause? transmission and treatment?
typhoid and paratyphoid (enteric fever).
faecal-oral.
ciprofloxacin.
150
what disease does Salmonella enteritidis cause? transmission? treatment?
gastroenteritis (food-poisoning). transmitted in under-cooked food contaminated with infected animal faeces. no treatment - self-limiting disease.
151
what disease does Shigella dysenteriae cause? transmission and treatment?
bacillary dysentery. faecal-oral. ciprofloxacin.
152
give some examples of parvobacteria
Haemophilus influenzae, Bordatella pertussis, Legionella pneumophila, Campylobacter jejuni.
153
what diseases does Haemophilus influenzae cause?
meningitis, osteomyelitis, cellulitis, otitis media, septic arthritis, pneumonia.
154
how would you treat an H influenzae infection?
cefotaxime or ceftriaxone
155
what disease does Bordatella pertussis cause? transmission and treatment?
whooping cough. airborne droplets. erythromycin.
156
what disease does Legionella pneumophila cause? transmission and treatment?
```
Legionnaires disease (severe pneumonia, high fever). transmitted by aerosolised droplets - found in warm water such as air con units, water tanks.
treat with erythromcyin.
```
157
what does Campylobacter jejuni cause? transmission? treatment?
gastroenteritis ± dysentery - food poisoning.
reactive arthritis.
Guillain-Barre.
transmitted in contaminated poultry or unpasteurised milk.
no treatment - self-limiting.
158
what diseases does H pylori cause? how would you treat?
chronic gastritis. duodenal and gastric ulcers. increased gastric cancer risk.
treat - clarithromycin and amoxicillin or metronidazole.
PPI (omeprazole).
159
what disease does Vibrio cholerae cause? transmission and treatment?
cholera - rice water diarrhoea, 25l/day.
faecal-oral / seafood.
treat - rehydration.
160
what diseases does pseudomonas aeruginosa cause?
pneumonia (esp. in CF patients).
IV catheter infections.
folliculitis.
UTIs, esp. with catheters.
161
how would you treat a patient with a Pseudomonas aeruginosa infection?
severe cases - gentamicin or ceftazidime (IV).
| in CF/bronchiectasis - ciprofloxacin.
162
what 8 important bacterial groups stain poorly/not at all with Gram stain?
```
Chlamydia spp.
Coxiella spp.
Ricksettia spp.
Mycobacteria spp.
Trepnonema spp.
Borrelia spp.
Leptospira spp.
Mycoplasma spp.
```
163
What diseases are caused by Chlamydia trachomatis?
chlamydia.
trachoma - chronic follicular keratoconjunctivitis.
Reiter's syndrome/
PID.
164
what is the route of transmission of Chlamydia trachomatis?
mucosal contact
165
how would you treat a patient infected with Chlamydia trachomatis?
doxycycline or azithromycin
166
what disease is caused by Chlamydia psittaci? treatment?
pigeon fanciers lung. tetracylcine.
167
what culture medium is used for Mycobacteria? how long should the culture be grown for?
Lowenstein-Jensen culture medium. up to 12 weeks.
168
what disease is caused by Mycobacterium leprae? transmission and treatment?
Leprosy. aerosol droplet spread.
| Rifampicin and dapsone.
169
what disease is caused by Treponema pallidum? transmission and treatment?
Syphillis. tramission is through broken mucosa during sexual contact, or blood transfusion.
treatment - penicillin or doxycycline.
170
give some examples of spirochaete bacteria
Treponema spp.
Borrelia spp.
Leptospira spp.
171
what type of virus is the herpes simplex virus? what diseases does it cause?
DNA virus.
HSV1 = cold sores.
HSV2 = genital herpes.
172
how would you treat a herpes simplex infection?
aciclovir, famciclovir or valciclovir
173
what type of virus is the varicella-zoster virus? what diseases does it cause?
DNA virus.
chicken pox.
reactivation = shingles.
174
how would you treat someone infected with varicella zoster?
child - calamine lotion.
| adolescents/adults - aciclovir.
175
what type of virus is cytomegalovirus?
DNA virus.
176
what type of virus is Epstein-Barr virus? what diseases does it cause?
DNA virus.
infectious mononucleosis (Glandular fever).
Burkitt's lymphoma/Hodgkin's disease.
177
what type of virus is the influenza virus? how is it transmitted?
RNA virus.
| droplet spread.
178
what type of virus is the mumps virus? how is it transmitted?
RNA virus.
| droplet spread.
179
what are the clinical features of mumps?
prodrome - headache, malaise, fever.
enlarged parotid gland.
orchitis.
180
what type of virus is the measles virus? how is it spread?
RNA virus.
| droplet spread.
181
what are the clinical features of measles?
Prodromal illness.
| fever. rash - erythematous and maculopapular.
182
what type of virus is the coronavirus? what does it cause? how it is spread?
RNA virus.
common cold.
droplet spread.
183
what type of virus is the rotavirus? what does it cause? how is it spread?
RNA virus.
gastroenteritis.
faeco-oral + direct spread.
184
name two groups of yeasts
candidia spp. and cryptococcus spp.
185
where is Candida albicans found? how is it transmitted?
oropharynx, vagina, GI tract.
| disruption of normal bacterial flora leads to Candida overgrowth.
186
what diseases does Candida albicans cause?
vaginal and oral candidiasis (thrush).
skin/nail infections.
UTIs.
187
what type of protozoa is entamoeba histolyica? what disease does it cause?
an amoeba.
| causes amoebic dysentry - faeco-oral transmission.
188
what are the clinical features of amoebic dysentery?
abdo pain.
severe diarrhoea with blood and mucus.
tenesmus.
hepatomegaly.
189
how would you treat amoebic dysentery?
metronidazole.
190
what type of protozoa is giardia lamblia? what disease does it cause?
flagellate.
causes diarrhoea, including travellers diarrhoea.
faeco-oral.
191
give an example of a cestode
taenia solium - pork tapeworm
192
give an example of a trematode
schistosomes
193
what colour do Gram +ve bacteria stain?
Purple (Positive = Purple)
194
what colour do Gram -ve bacteria stain?
red/pink
195
what worm is the most common cause of iron-deficiency anaemia worldwide?
hookworm
