Microbiology Flashcards
(154 cards)
1
Q
1st line treatment for severe falciparum malaria?
A
Artesunate
2
Q
Diarrhoeal illness species which is most likely to develop into a chronic state
A
Typhoid
3
Q
Complications of MUMPS
A
Meningitis / post meningitis deafness / encephalitis / pancreatitis / orchitis / oophoritis
4
Q
Which infection is subacute sclerosing panecephalitis associated with?
A
Measles
5
Q
FBC result in whooping cough
A
Lymphocytosis
6
Q
Acute hepatitis B serology
A
HBsAg, HBeAg, Anti-HBc IgM
7
Q
Chronic hepatitis B serology
A
HBsAg, anti-HBe, anti-HBc IgG
8
Q
Cleared infection Hep B serology
A
Anti-HBs, anti-HBe, anti-HBc IgG
9
Q
Vaccinated against HepB serology
A
Anti-HBs
10
Q
Which drugs are used in each phase of TB tx
& timeframe
A
Initial - Isoniazid, rifampicin, ethambutol, pyrazinamide (2 MONTHS)
Continuation - Isoniazid & rifampicin (4 MONTHS)
11
Q
Herpes simplex encephalitis, which region of the brain is abnormalities seen on imaging?
A
Temporal lobe
12
Q
Infective endocarditis in IV drug users most commonly caused by which pathogen?
A
Staph. areus
13
Q
First line treatment for typhoid fever?
A
Cefotaxine / ceftriaxone
14
Q
How does N.gonorrhoea adhere to genital mucosa?
A
Using fimbriae
15
Q
Most common cause of gastroenteritis …
- Adults
- Children
A
Norovirus
Rotavirus
16
Q
Define incubation periods
A
the period between the infection of an individual by a pathogen and the manifestation of the illness or disease it causes
17
Q
Incubation period for rubella
A
2-3 weeks
18
Q
How does Giardia attach to gut mucosa?
A
Sucking discs
19
Q
How to E.coli attach to host epithelial cells in the urinary tract
A
Pili
20
Q
When is Hep B given in the childhood vacc schedule?
A
2,3,4 months
21
Q
N. Goborrhoeae mechanism of attachment
A
Fimbriae
22
Q
Deficiency in what makes you particularly susceptible to herpes simplex?
A
T cell deficiency
23
Q
What causes T cell deficiency (4)
A
HIV infection
Chemo
Corticosteroid therapy
Organ transplant
24
Q
Which malaria pathogen causes the most severe and progressive illness?
A
Falciparum
25
What % of Hep B infections become chronic?
10%
26
Rheumatic fever is...
Post infectious immune-mediated reaction secondary to Streptococcus pyogenes
Characterised by myocarditis, endocarditis, reactive arthritis, chroea and skin complaints
27
Tx for F.malariae which can be used in those pregnant in all trimesters? (2)
IV artesunate
OR
Quinine with clindamycin
28
1st line in osteomyeletitis
Flucloxacillin
29
Commonest helminth in the UK
Threadworm
30
Where do the threadworm ova hatch
Upper GI tract (digestive juices activate)
31
Tx for threadworm
Combined family hygiene methods
+ mebendazole
(single dose, second dose can be given after 2 weeks).
32
Cysticercosis
Larvae of tape worms enter the blood stream and dissemintate forming cyst like lesions in muscles / skin / eyes and brain (neurocysticercosis)
33
Tx for tapeworms
Niclosamide / Praziquantel
34
Complications of roundworm infection
Pneumonitis
Intestinal obstruction
Malnutrition
Hepatic abscess
35
Tx for round worm
Mebndazole
36
How is hookworm usually acquired?
Walking barefoot in soil contaminated with human faeces
37
Tx for hook worm
Mebendazole
38
Define malaria
Ix of RBC caused by a protozoan parasite
39
Which RBC defects confer some protection against P.falciparum
Sickle cell
Thalassaemia
G6PD deficiency
40
Where do malarial sporozoites replicate / mature
Liver
41
What is released into the blood steam following maturation of sporozoites in the liver?
Which invade what?
Forming what?
Merozoites which invade erythrocytes forming erythrocytic schizonts
42
What causes the clinical features of malaria
erythrocytic schizonts RUPTURE -> release merozites and desctruct RBC -> acute inflamm response -> cytokines
43
Uncomplicated malaria sx
Fever, chills, sweats, headaches, muscle pains, N&V
44
Severe malaria sx
Confusion, coma, focal neurological sx, severe naeamia, reap difficulties
45
Common cause of severe malaria
Plasmodium falciparum
46
When should a dx of malaria be considered?
Acutely unwell / pyrexic travellers returning from endemic areas
47
What is required to exclude a malaria diagnosis?
3 negative malaria smears 12-24hrs apart
48
In context of malaria...
Thick blood film used for what ?
Thin?
Confirm malaria diagnosis
Diagnose species of plasmodium
49
Which malarial sporozites can become latent hynozoites and reactivate months / years later?
P. ovale and P. vivax
50
Recommended tx for uncomplicated P. falciparum malaria
Artemisinin combo therapy
51
How is specific causes of GI viral infections diagnosed?
NAAT of stool sample
52
Why can norovirus ccur in people of all ages?
Because immunity is not long lasting
53
Most common cause of gastroenteritis in children?
Rotavirus
54
When is the rotavirus vaccine given in children?
2 & 3 MONTHS
55
Where is candida spp. found naturally in the body?
Skin, GI tract, female genital tracr
56
What does candida look like on microscopy?
Gram +ve spores and pseudohyphae
57
Intense exposure to what can put you at risk of cryptococcus?
Pigeons
58
Cryptcoccus neoformans transmission
Inhalation of spores from bird drppings
59
Diagnosis of Cryptcoccus
Direct microscopy of CSF, antigen detection of latex-agglutination test or culture
60
Tx of cryptococcus meningitis
Amphotericin or flucytosine
then oral fluconazole for 8 weeks or unti cultures -ve
61
Oral tx for dermatophytes?
Terbinafine
62
Klebsiella spp. bacterial properties
Anaerobic
Gram neg
Rods
OPPORTUNISTC
63
Klebsiella spp. found where in the body ?
GI and URT
64
Klebsiella spp. typically cause what type of infection?
Noscomal ix
65
Common infections caused by Klebsiella spp.
Ventilator associared pneumonia
Catheter associated UTI
Device related / wound infectin
Septiicaemia
Neonatal meningitis
66
Characterisation of Klebsiella spp. CAP
Rare
Severe
Red current jelly sputum
67
Salmonella spp. characteristics?
Anaerobic
Gram -ve
Bacilli
68
Presentation of enteric (typhoid) fever?
Fever, systemic upset, abdominal pain, alteration of bowel habit, splenomegaly, rash of rose spots
69
What happens to typhoid chronic carrier?
Gall bladder and bowel colonisation
70
Tx of salmonella entercolitis?
Self limiting usually
If severe - cipro or cefotaxime
71
First line tx for typhoid fever?
Cefotaxime
72
E. coli characteristics?
Anaerobic
Gram negative
Bacilli
73
Pathogenic mechanisms of E.coli strains
Pili (particularly in urinary tract)
Capsule
Endotoxin
Exotoxins
74
Why are newborns exposed to E.coli?
Colonisation in the the vaginal canal
75
Types of diarrhoea caused by E.coli strains
Exotoxin mediated watery (travellers)
Enteroinvasive disease
Haemorrhagic dysentery
76
Characteristics of H. pylori
Motile
Gram neg
Spiral bacillus
77
Where doea H. pylori exclusively live?
Gastric mucosa
78
What does H. pylori secrete to protect itself?
Urease, raises gastric pH
79
Characteristics of Campylobacter jejuni
Gram -ve
Rod
80
Typical clinical features of Campylobacter ix
Fever
Flu like illness
Abdo pain / cramps
Profuse / occasionally blood diarrhoea
N&V
81
Tx of Campylobacter ix
Usually self limiting
1st line clarithromycin
82
Complication of Campylobacter ix (2)
Reactive arthritis
Gullain-Barre syndrome
83
Clostridium perfringens characteristics
Gram postivie rod, obligate anaerobe, spore forming and produces an exotoxin
84
Clostridium perfringens typically causes
Gas gangrene / food poisoning
Gas gangrene is a form of necrotising fasciitis caused by Clostridium species (most commonly C. perfringens), resulting in gas being produced by the bacteria within the tissue.
85
Clostridium tetani characteristics?
Gram +ve, rod, obligate anaerobe, spore forming, produces tetanospasim
86
What disease does Clostridium tetani cause?
Tetanus
87
C.diff characteristics
Gram +ve, rod, obligate anaerobe, spore forming, produces Toxin A (enterotoxin) and B (cytotoxin)
88
C.diff causes
Pseudomembranous colitis
89
What do c.diff toxins do
Cause intestinal fluid secretion, tissue damage resulting in profuse watery diarrhoea, abdo cramps, fever, rigors and sepsis
90
Complications
of pseudomembranous colitis
Toxic megacolon
Bowel perforation
Dehydration
AKI
Electrolyte disturbance
Systemic toxicity
91
Pseudomembranous colitis tx
Stop implicated abx
1st line - vancomycin orally QDS for 10 days
2nd line Fidaxomicin
Fluid and electrolyte management
Strict barrier / isolation, hand washing
92
Management of gas gangrene
Rapid surgical debridement of necrotic tissue
Fasciotomy
Removal of FB
Wound cleansing and packing
Abx - penicillin, gentamicin, metronidazole
Consider hyperbaric O2 therapy
93
MOA of tetanospasmin
Impaires the the membrane of syntaptic vesicles, presents release of GABA at pre-synaptic membrane, nil inhib control -> spasm
94
Incubation period of C. tetani
Av 10 days (3 - 22)
95
Tx for C.tetani
Wound debridement
Abx - metronidazole
IV TETANUS IMg
Tetatnus toxid immunisation
Benzos, non dpol NMB and baclofen for spasms
Supportive care
96
Immunisation schedule for tetanus
2 months
3 months
4 months
3.5 - 5 years
13 - 18 years
97
N. meningitidis characteristics
Gram negative cocci, aerobe, encapsulated
98
What doe N. meningitidis cause
Meningitis and meningococcal sepsis
99
Why do those with complement deficiencies have an increased of developing meningococcal bacteriaemia?
Immunity is dependent on compliment activation
100
CSF in meningitis:
Cloudy and turbid
Raised WCC - mainly neutrophils
High protein
Low glucose
Gram -ve diplococci on microscopy
101
Vaccines against N.meningitidis
Men B - 2,4,& 12 months
MenC - 1yr
Men ACWY - 14yrs
102
N. Gonorrhoeae characteristics
-VE Gram stain
Cocci
Aerobe
103
N. Gonorrhoeae can cause...
Urethritis, epidiidymo-orchitis, PID, septic arthritis, endocarditis, neonatal conjunctivitis
104
How does N. Gonorrhoeae adhere to epithelium
Pili
105
1st line tx for N. Gonorrhoeae
STAT IM Cef
Azithromycin as a single dose
106
Typical CXR findings in TB
Upper lobe involvement with cavitation / consolidation / fibrosis
107
Initial phase of TB tx
2 months
Isoniazid
Rifampicin
Pyrazinamide
Ethambutol
108
MOA of quinolones
Interfere with bacterial nucleic acid synthesis
109
CSM warning re quinolones
May induce convulsions, increased risk if take an NSAID with it
(GABA antagonists)
110
Caution with use of quinolones over which age?
60 +
111
Caution with use of quinolones due to risk of tendon damage, taking which medication alongside?
Corticosteroids
112
Ciprofloxacin dose in uncomplicated gonorrhoea
500mg 1 dose
113
Within what timeframe should an antiviral be started in shingles?
72hrs
114
Who may require post-exposure prophylaxis of varicella zoster infection?
Neonates
Pregnant women
Immunocompromised individuals
115
What can be given to tx severe or complicated falciuparum malaria if artesunate not available?
Quinine IV, should complete the course
Add doxy when able to swallow
116
Quinine potential SE in pregnancy?
Increase risk of uterine contractions and hypoglycaemia
117
Legionella characteristics
Gram -ve, rod, obligate aerobes
118
Characteristics of legionella?
Gram neg, rod, obilgate aerobes
119
Host risk factors for legionella pneumonia?
Male
Older
Previous lung disease
Smoking
High alcohol intake
Immunosupression
120
Systemic features associated with legionnaires disease
Nausea, vomiting, diarrhoea, headache, malaise, confusion and renal failure
121
Characteristics of pseudomonas?
Gram negative rod, obligate aerobe
122
Risk factors for pseudomonas
CF
Burns
IV drug users
Diabetes mellitus
Neutropenia
Immunosuppression
Indwelling catheter
123
Chlamydia trachomatis characteristics
Gram negative obligate intracellular organisms
124
Chlamydia peripartum transmission can caused what Ix in the neonates?
Neonatal opthalmic infection / pneumonias
125
What can be given to pregnant women who are not immune to VSZ virus who have had significant contact with an infected person?
varicella-zoster immunoglobulin (VZIG) within first 10 days of contact
(in the case of continuous exposures, this is defined as 10 days from the
appearance of the rash in the index case). 3
126
Obligate pathogen =
Require a host to fulfil their life cycle. All viruses are obligate pathogens as they are dependent on the cellular machinery of their host for their reproduction.
127
Giemsa stain used to identify?
Malaria
128
Fluorescent
microscopy used to identify?
RSV
129
Which antibodies are diagnostic for Hep A?
Anti- HAV IgM antibodies
130
When is faecal shedding demonstrated in Hep A infection (in relation to jaundice sx)
For 2-3 weeks before and a week after
131
Measles:
transmission
incubation period
Respiratory droplet route
9 - 12 days
132
Measles - relation of infectivity to rash
Patients are infectious from about 3 days before rash emerges to 4 days after
133
Measles, key exam finding in the mouth
Koplik spots (white papules on buccal mucosa),
134
Measles rash
Maculopapular rash appearing first behind the ears and spreading to whole body, rash resolves after 7 - 10 days
135
When is the MMR vaccine given?
1 y/o AND at pre school age (3 yrs + 4 months)
136
Mumps:
Transmission
Incubation
Respiratory droplet
14 - 24 days
137
Key distinguishing features in Mumps
Bilateral tender parotitis, usually resolves after about 7 - 10 days
138
Measles secondary complications:
Secondary bacterial infection (pneumonia, bronchitis, otitis media), encephalitis, subacute sclerosing panencephalitis
139
Rubella secondary complications:
Arthritis, encephalitis, congenital rubella syndrome (deafness, cataracts, cardiac defects, microcephaly, cognitive impairment, intrauterine growth restriction)
140
Congenital rubella syndrome
- which trimester has highest risk?
- Potential complications of maternal ix
1st
Foetal death
Severe abnormalities - sensorineural deafness / cataracts / cardiac / microcephaly / IUGR / cognitive impairment
141
Complications of Mumps
Meningitis, post meningitis deafness, encephalitis, orchitis (+ infertility), oophoritis, pancreatitis
142
What organisms are most common causes of neonatal meningitis?
Group B strep (+ve cocci) and E. Coli (-ve rods)
143
Characteristics of streptococcus pneumoniae
Gram +ve, cocci, anaerobe
144
Most common cause of CAP
streptococcus pneumoniae
145
Characteristics of streptococcus pyogenes
Gram +ve, cocci, anaerobe
146
Streptococcus pyogenes also know as?
Group A beta-haemolytic streptococci
147
How is Streptococcus pyogenes spread?
Respiratory droplets or direct contact with infected wounds on the skin
148
How is streptococcus pneumoniae spread?
Respiratory droplet
Ix can be endogenous also
149
Staph Aureus characteristics?
Gram +ve, cocci, anaerobe
150
What is beta haemolysis ?
Beta-hemolysin breaks down the red blood cells and hemoglobin completely. This leaves a clear zone around the bacterial growth. Such results are referred to as β-hemolysis (beta hemolysis).
151
What is alpha haemolysis ?
Alpha-hemolysin partially breaks down the red blood cells and leaves a greenish color behind.
152
Staph epidermis characteristics?
Gram +ve, cocci, anaerobe
153
Staph epidermis usually involved in infections.
Devices (cardiac / lines / prosthetic)
154
