infections Flashcards
(85 cards)
1
Q
list the bacteria sought by routine cultures of stools from patients with diarrhoea in the u.k.
A
campylobacter gastroenteritis
salmonella gastroenteritis
E.coli O157
2
Q
campylobacter commonly arises from
A
food poisoning
3
Q
salmonella gastroenteritis is symptomatic after how many hours?
A
48
4
Q
how many days does a salmonella gastroenteritis infection be active for?
A
10
5
Q
E. coli O157 route of infection
A
meat to person
6
Q
list other potential bacteria for diarrhoea
A
shigella E.coli staph aureus bacillus cereus clostridum perfringens C. difficile
7
Q
4 C’s related to C difficile
A
cephalosporin’s
co-amoxiclav
clindamycin
ciprofloxacin
8
Q
clostridium perfringen’s vector of infection
A
undercooked meat
9
Q
bacillus cereus may arise from
A
Re-fried rice
10
Q
list parasite that may cause diarrhoea
A
Protozoa giardia duodenalis
Protozoa cryptosporidium parvum
11
Q
Protozoa Giardia duodenalis may arise from and how many cases?
A
direct contact with cattle, or food/water infected with faeces. 200 cases a year in Scotland.
12
Q
protozoa cryptosporidium parvum
A
contaminated water/food with faeces or animal.
and helminths.
13
Q
list viruses that commonly cause diarrhoea
A
rotavirus
norovirus
14
Q
rotavirus diagnosis is by
A
antigen in stool
15
Q
rotavirus is commonly associated with
A
children under 5
16
Q
norovirus is commonly associated with
A
winter vomiting bug, common in institutions
17
Q
norovirus diagnosis is commonly by
A
PCR
18
Q
gastroenteritis definition
A
3 or more loose stools a day with accompanying features such as pain and fever
19
Q
dysentery definition
A
large bowel inflammation with bloody stools
20
Q
normal bowel defences
A
stomach acidity, normal gut flora, immunity
21
Q
what percentage of the population are due to infectious intestinal disorders each year
A
25%
22
Q
what percentage of GP visits are because of a GI infection
A
2%
23
Q
Cholera pathophysiology
A
increased cAMP results in loss of Cl from cells with loss of sodium and potassium, osmotic effect draws water into lumen leading to dehydration
24
Q
E. coli O157 produces which toxin?
A
Shiga
25
C. difficile produces what toxins?
enterotoxin and cytotoxin
26
assessments for enteritis
assess risk of food poisoning, travel, diet and contacts. Then hydration (postural BP, turgor, pulse), check for fever, raised WCC.
27
investigations for enteritis
stool culture Ag, blood culture, renal function, blood count, abdominal X-ray
28
C. difficile treatment
metronidazole, oral vancomycin, fidaxomicin, stool transplants
29
parasite infection diagnosis
microscopy
30
protozoa giardia duodenalis treatment
metronidazole
31
complications of a E. coli O157 infection
Shiga toxin can enter the blood causing haemolytic uraemia syndrome leading to renal failure, haemolytic anaemia, thrombocytopenia.
32
colonisation refers to
process of establishment of the microbe in the body tissue
33
infection refers to
– process of invading body tissue causing symptoms of a disease
34
host factors that enable an infection to spread/occur
underdeveloped immune system, decreasing immune system, drugs or diseases, tubes.
35
first step in the chain of infection
infectious agent
36
how to break the first step of infection in the chain
diagnosis, treatment, anti-microbials
37
second step in the chain of infection
reservoir
38
how to break the second step of infection in the chain
cleaning, sterilisation, disinfection, policies, pest control
39
third step in the chain of infection
portal of exit
40
how to break the third chain of infection
hand hygiene, PPE’s, control of aerosols and splatter, respiratory etiquette, waste disposal
41
fourth step of the chain of infection infection
mode of transmission
42
how to break the fourth step of the chain of infection
hand hygiene, food safety, cleaning, sterilisation, disinfection, isolation, PPE
43
fifth step of the chain of infection
portal of entry
44
how to break the fifth chain of infection
removal of tubes and catheters, hygiene, hand hygiene, PPE’s, first aid
45
6th chain in infection
susceptible host
46
how to break the 6th chain of the infection
vaccines, treat underlying disease, patient education
47
cleaning refers to
physical removal or organic material and decrease in microbial load. E.g. skin, stethoscopes, beds
48
disinfection refers to
large reduction in microbe numbers – mucous membrane contacts, endoscopes. Can be pasteurisation, boiling, or chemical such as alcohol.
49
sterilisation refers to
removal/destruction of all microbes and spores. – surgical equipment. Can be autoclaved, hot air oven, gas (ethylene dioxide), ionising radiation.
50
sepsis refers to
systemic illness caused by microbial invasion of normally sterile parts of the body resulting in life threatening organ dysfunction caused by dysregulation of host response
51
septic shock refers to
identified by persisting hypotension requiring vasopressors to maintain mean arterial pressure >65mm Hg and having a serum lactate >2mmol/l despite adequate volume resuscitation
52
For each hour’s delay in administering antibiotics in septic shock, mortality increases by
7.6%
53
general pathophysiology of sepsis
there is a breach in the integrity of the host barrier, the organism enters the blood stream creating a septic state. There is an uncontrolled inflammatory response. Patients with sepsis have the inability to clear the infection, predisposition to nosocomial infection and loss of delayed hypersensitivity. This starts with the increase in inflammatory mediators and later a shift to anti-inflammatory immunosuppressive phase.
54
phase one of sepsis
bacterial invasion; negative with lipopolysaccharide or positive microbial associated molecular pattern or superantigens
55
phase two of sepsis
endotoxin lipopolysaccharide or exotoxins which stimulate pro-inflammatory response, such as superantigens stimulating a cascade response
56
phase 3 of sepsis
proinflammatory; promote adhesion between endothelial cells and leukocytes, release of arachidonic acid metabolites, complement activation, vasodilatation by NO, increased coagulation and hyperthermia.
57
reasons for differential presentations for sepsis
may present differently due to Age, co-morbidities, immunosuppression or prior surgeries. Then there is the effects of gram positive versus gram negative, virulence factors or bioburden. Then there is the effect of the environment on the presentation with occupation, travel and hospitalisation.
58
clinical presentation of sepsis and septic shock
altered consciousness, tachypnoea (PaO2 <70mmHg, Sats <90%), jaundice (increased liver enzymes, reduced albumin, increased prothrombin time, reduced platelets and protein C and increased D dimer), tachycardia, hypotension, oliguria, anuria and increased creatinine, fever, chills, rigors, flushes, cold sweats and night sweats, hypothermia
59
what is the outline of the sepsis 6
```
Oxygen
Blood cultures
antibiotics
fluid challenge – 30ml/kg
lactate - A hypoperfusions, B mitochondrial toxins, alcohol
urine output
```
Take three, give three
60
2 C's of sepsis 6
crystalloid bolus and catheter to see if renal dysfunction for low urine output.
61
2 B's for sepsis 6
blood cultures for microbiological diagnosis (if spike in temperature then take 2), blood lactate for marker of generalised hypoperfusion/ severe sepsis/ poorer prognosis.
62
2 A's of sepsis 6
Air enriched with oxygen, antibiotics after blood culture.
63
HDU for sepsis if
if low B.P, lactate > 2, elevated creatinine, oliguria, liver dysfunction or bilateral infiltrates.
64
what percentage of healthy person may be colonised by S. Aureus
25-50% of a healthy person may be persistently or transiently colonised.
65
rate of S. Aureus colonisation is increased by
Rate of colonisation is higher among patients with insulin dependent diabetes, HIV infection, patients undergoing haemodialysis and individuals with skin damage.
66
sites of S. Aureus reservoir
Most frequent site of colonisation is the anterior nares. Skin such as the vagina, axilla, perineum or oropharynx may also be colonised and act as a reservoir for future infections.
67
investigations of S. Aureus bacteraemia
microscopy and multiple cultures of specimens, repeat one 48-72 hours after antimicrobial therapy. Biopsy for bone infections. Imaging X-Ray, Ct, MRI, radionuclide imaging, transthoracic ECHO and TOE.
68
drugs for management of S. Aureus bacteraemia
flucloxacillin, vancomycin, teicoplanin, linezolid, daptomycin
69
influenza virus is what sort of virus and with how many groups
RNA virus with 3 main groups
70
antigenic drift refers to
mechanism of genetic variation within the virus. Occurs gradually small point mutations which may alter the antigenic properties allowing it to evade immune responses
71
antigenic shift refers to
abrupt major H/N changes that allow a shift in flu from one species to another. There is reassortment of virus gene segments. New antigenic properties the population is unprotected and this can lead to pandemics.
72
seasonal influenza affects what percentage every winter?
10-55%
73
pandemic refers to what percentage infected?
25%
74
laboratory diagnosis of influenza
viral nose and throat swabs, CXR, blood culture, pulse oximetry, respiratory rate, U+E’s, FBC, CRP
75
presentation of influenza
incubation of 2-4 days, abrupt fever up to 41 degrees lasting for 3 days. Plus 2 or more of cough, sore throat, rhinorrhoea, myalgia, headache, malaise. Systemic symptoms and less common nausea, vomiting and diarrhoea.
76
complications of influenza
respiratory (acute bronchitis, secondary bacterial pneumonia), cardiac (myocarditis/pericarditis), CNS (transverse myelitis/Guillain barre, myositis). Encephalitis lethargy (fever, headache, ophthalmoplegia, lethargy, sleep reversal). Secondary bacterial pneumonia ( flu like symptoms and fever for >4 days require CXR).
77
describe the role of antiviral agents in the treatment of influenza
use quickly within 48 hours of symptom onset. There is complicated at risk then first line oseltamivir or zanamivir second line. Complicated or uncomplicated low risk then oseltamivir and zanamivir for 1st and 2nd.
78
role of immunisation in preventing outbreaks
prepared each year using most likely circulating virus grown in chicken embryos with a single intramuscular injection. Healthcare workers being vaccinated enables protection, reduces risk and minimises absences for sick days
79
zoonosis is defined as
infections that can pass between living animals and humans
80
what percentage of pathogens are zoonotic
61%
81
brucellosis acute features
Acute are fevers, weakness, headaches, sweats, splenomegaly. Subacute is fever and joints
82
brucellosis chronic features
chronic as flu, malaise, depression, chronic arthritis, endocarditis but most commonly subclinical.
83
brucellosis aetiology
infected by milking infected animals, parturition, handling carcasses, consumption of unpasteurised dairy products
84
leptospirosis features
flu like symptoms, jaundice, renal failure from many reservoir hosts.
85
treatment of brucellosis
serology, long acting doxycycline + rifampicin.
