IV - Microbiology & Infection - Epidemiology and infections

Question 1

Why is it important to have a record of the amount of cases of infection?

Answer 1

The amount of cases of infection is important as allows us as pharmacists to be prepared.

• There needs to be record keeping for this
• So we know how much to stock up on in our pharmacies whether that be in hospital or community.
• This is important and relevant to us as at the moment there is a shortage of flu vaccinations.

Question 2

What is epidemiology?

Answer 2

Epidemiology is the study of where and when diseases occur

- How they are transmitted within populations, this helps with infection control and prevalence

Question 3

How is the occurrence of a disease measures?

Answer 3

Occurrence of disease measured by:

• Incidence: This is the number of new cases of infection in a given population (e.g. for HIV the number of new cases may be 40,000 in 2018.) This may need more medications.
• Prevalence: This is the number of existing cases of infection in the same population (e.g. the number of existing cases of HIV may be 400,000 in 2018.) This needs medications to be maintained.

Occurrence then is a combination of the two being 440,000.

Question 4

What is a spatial risk gradient?

Answer 4

Spatial risk gradient. This represents the hotspot for an infection. The closer you are to the hotspot, the more likely you are to developing that infection and vice versa. Red usually represents higher risk and blue represents lower risk. There is a scale to show what each colour represents

Question 5

What is a choropleth map?

Answer 5

Choropleth map, which looks at incidence of infection in a set number of people (e.g. per 1000 people.) The darker the area the higher the incidence.

Question 6

What is a dot map?

Answer 6

Dot map, which is used to usually represent the occurrence of infection in an area. Each dot represents a certain amount of people. There are now interactive maps, which you can click a dot and it will tell you how many people it represents, the details of the patients and what kind of infection it was.

Question 7

What is a phylogenic tree?

Answer 7

Phylogenic tree, which shows how an infection has evolved, how they have changed, how resistant has developed (changes in mutations and it spreading) and the different strains of the bacteria (e.g. some strains of E.coli are dangerous and others are not.) This looks at the genetics of an infection. Also there are some viruses that combine such as swine flu and bird flu, which are combinations of flu. Bird flu has two parts that derive from a flu virus that affected bird and one part from humans. Resistant is more common for viruses than bacteria.

Question 8

What is a social network diagram?

Answer 8

Social network diagram. This looks at how infection spread from person to persona and social aspects. This can be individual cases represented by numbers or groups of people. Then you indicate how they have spread. E.g. family members may be represented as circles and colleagues at work may be represented as squares and strangers may be triangles. The lines can also be used to represent different things. Like a dotted line may mean that they are married or have had close contact. This allows us to see how infections can spread in a community and this helps with infection control

Question 9

What is an Endemic infection?

Answer 9

A disease that normally occurs continually at a relatively stable incidence within area/population (something that is common, such as in winter there is a high occurrence of colds and flus, for which there is an expected number. This could be 5 million people in the UK.)

Question 10

What is a Sporadic infection?

Answer 10

Only a few scattered cases occur within area/population. This may be unusual or of higher frequency.

Question 11

What is an Epidemic?

Answer 11

• Diseases occurs at greater frequency/incidence than usual within area/population
• Epidemics of the same infection occurring in more than one country is called a pandemic.

Question 12

What is a Nosocomial Infection?

Answer 12

Exogenous nosocomial infections.

• Pathogens acquired from the healthcare environment to the patient
• This is common in a hospital environment

Endogenous nosocomial infections

• Arise from the normal microbiota within the patient
• For example the streptococci pneumonia, which is a commensal bacteria found in the nasal pharynx. If immunocompromised then you can be affected by something like this which is already living in the body.
• Some hospitals do testing on patient for potential MRSA, by given prophylactic antibiotics but it can come from themselves too.

Iatrogenic infections

• Subset of nosocomial infections that are a direct result of medical procedures
• For example, surgery, or simple thing like putting in catheters or injection lines.

Superinfections may result from use of (more potent) antibiotics, i.e. allowing opportunistic pathogens to thrive (resistant organisms develop and are passed on from person to person.)

Question 13

What are factors affecting nosocomial infections?

Answer 13

• Exposure to numerous pathogens due to more and more patients coming in
• Weakened immune system of host
• Transmission of pathogens among patient and healthcare professionals as well as visitors

Question 14

How can we control nosocomial infections?

Answer 14

• Aggressive control measures can reduce incidence, these have severe side effects
• Includes disinfection, hand gels/ hand washing (aseptic methods that has decreased nosocomial infections by 50%) medical asepsis, surgical asepsis, isolation of contagious or susceptible patients, establishment of nosocomial infection control protocols

Question 15

What is Bacterial meningitis?

Answer 15

Microbial diseases of the CNS

This is not common but the early stages are more common in a younger population (small children/babies). This means that you are dealing with parents.

• Inflammatory bacterial infection of the meninges (in the CNS)
• Inflammation of spinal meninges puts pressure on surrounding nerves and muscles
• When brain becomes infected – encephalitis results
• More than 50 species of bacteria can cause meningitis e.g. Neisseria meningitides (produces anti-phagocytic virulence factors), Streptococcus pneumoniae and Haemophilius influenza (this is commensal)
• Some of these organism are commensal organism that live in the body or can be ingested.
• It is important to identify the symptoms and signs of meningitis early on, as in certain cases 6 hours after the first symptom/sign the patient may die.
• Droplets inhaled and bacteria travel from lungs to meninges
• Treatment usually IV admin antimicrobials (this has 100% bioavailability.)

Question 16

What is Whooping cough?

Answer 16

Microbial diseases of the respiratory system

Pertussis (Whooping cough)
- This is common in young children and again you are dealing with parents
- Beginning signs and symptoms resemble common cold, after 1-2 weeks, signature severe coughing starts
- Caused by Bordella pertussis, it has virulence factors such as adhesins and toxins, which include
- Pertussis toxin (increase the mucus production in the lungs, allows a place for the organism to hide and rest), adenylate cyclase toxin (increases mucus production), dermonecrotic toxin (this causes localised constriction and damages capillaries- haemorrhage) and tracheal cytotoxic (inhibits the movement of cilia in the airways.)
- Causes mucus to be stuck and not be shifted
- It is called whooping cough due to high amounts of mucus that the body wants to remove. There is also constricted airways causing the whooping sound. They can cough really hard which can cause blood vessels in the eye to burst.
- Patients go through 30-40 coughing fits in a day.
- Characteristic whooping coughs occurs as patients coughs 2-3 times without inhalation,
followed by inhalation through congested trachea
- Treatment primarily supportive and vaccine is available. Can give advice like pain control or steam inhalation. Treatment is not necessary as it is not serious.