Antibiotics Flashcards
How can the use of antibiotics lead to an increase in clostridium difficile and illness?
Patients who are treated with multiple or broad spectrum antibiotics may see an increase in the amount of C.diff in their bowel. This is because as other bacteria is killed off due to the antibiotics the C.diff can grow and colonise more of the bowel. This can lead to a C.diff infections as it releases toxins. Symptoms include:
- diarrhoea several times a day - a high temperature/fever - loss of appetite - feeling sick - tummy pain
What are the aims of antibiotics stewardship?
- to reduce antibiotic consumption
- to restrict worst offender agents
- to promote logical antibiotic choices
- to limit ‘co-lateral damage’
What are antibiotics?
Drugs that are used treat or prevent some types of bacterial infection.
What are some of the antibiotic therapies that can be used?
- guided therapy
- empirical therapy
- prophylactic therapy
Describe guided therapy in relation to antibiotics.
- depends on identifying the cause of infection and selecting an agent based on sensitivity testing
- normally used in mild infections that can wait a few days to be treated e.g. cystitis and mild would infections
- rationalising therapy in patients already on treatment
Describe empirical therapy in relation to antibiotics.
- this is a best/educated guess therapy based on clinical/epidemiological acumen
- used when therapy cannot wait for a culture
- used in patients with more severe infection e.g. sepsis, meningitis
- delay in therapy would result in worsening of the condition
- therapy needs to cover all likely causes
Describe prophylactic therapy in relation to antibiotics
- used to prevent infection
- e.g. when healthy people are exposed to surgery, injury or infected material
- e.g. in immunocompromised people with HIV, undergoing organ transplant, splenectomy
What are the 2 ideal characteristics to consider when choosing an antibiotic?
- Target effects
- Avoid Co-lateral damage
Achieving target effects and avoiding co-lateral damage are often mutually exclusive.
What are the ideal characteristics of target effects in antibiotics?
- highly toxic to bacteria causing infection
- penetrate the body area affected by infection
- limit release of toxins from bacteria
- convenient administration
What are the ideal characteristics to avoid co-lateral damage in antibiotics?
- non toxic to patient
- limited effect on colonising bacteria which reduces:
- mucosal candida
- C.diff infection
- selection of resistant bacteria
- low potential for bacteria to escape treatment through developing resistance
What compromises are involved in guided therapy antibiotics?
- usually narrow spectrum antibiotics
- use antibiotic which has limited action to the bacteria causing infection
- if possible limit penetration to site of infection
- achieve clinical cure with as little impact on colonisation and resistance as possible
What compromises are involved in empirical therapy antibiotics?
- usually broad spectrum antibiotics
- use antibiotic which has extensive action against any bacteria which may be causing infection
- need to penetrate broadly throughout body
- accept that impact on colonisation and resistance may be greater
Why would Nitrofurantoin be chosen to treat an 86 year old women complaining of dysuria with E.coli in her urine?
- it is a narrow spectrum antibiotic
- will penetrate only into urine so little systemic exposure
- high rate of cure in uncomplicated UTI
Why would Co-amoxiclav and Clarithromycin be chosen to treat a 26 year old male who presents with fever, SOB and green sepsis and who is unwell with respiratory failure and sepsis?
Patient is severely unwell so cannot wait for treatment, therefore broad spectrum antibiotics are chosen in order to treat common causes of pneumonia. Once a blood culture has been examined a more specific/narrow spectrum antibiotic may be chosen.
What is a bactericidal antibiotic? Give an example.
An antibiotic which will kill the bacteria e.g. penicillin
- these will achieve sterilisation of the infected site
- lysis of bacteria can lead to release of toxins and inflammatory material
