General Principles Of Treatment And Selection Of Antimicrobial Regimens Flashcards
If you get a positive culture sample from non-sterile sides e.g wounds and catheter urines, should you give antibiotic treatment?
No as they do not necessarily warrant treatment
Name some life-threatening infections requiring immediate treatment
Sepsis Neutropenia sepsis Meningitis Meningococcal sepsis Encephalitis Epiglottis Necrotising fasciitis Toxic shock syndrome
Name some factors in choosing antibiotics
Empirical treatment = best guess
Site of infection Seriousness Likely organism Patient factors Cost Toxicity and side effects Local/national resistance rates Other underlying diseases Contraindications
Factors to assess whether the drug is safe in this patient
Known allergy
Impaired excretion
Drug interactions e.g. ciprofloxacin and theophylline
Higher risk of toxic affects
Pregnancy and breast feeding
Antibiotic associated diarrhoea risk
There are two types of agents, bactericidal or bacteriostatic .
Cidal (penicillins, ciprofloxacin and gentamicin)
Static (tetracyclines, sulphonamide)
Give situations when cidal agents would be preferred
Immunocomprimised (seriously ill and steroid therapy) Immunodeficiency (neutropenia, HIV) Difficult sites (endocarditis, meningitis)
After reviewing treatment , what should happen
Stop if no evidence of infection Switch from IV to oral Change antibiotics to narrow Continue and review Outpatient parental antibiotic therapy
Why switch from IV to oral for antibiotics?
Reductions in hospital-required bacteraemias and infected/phlebitic lines
Saves medical and nursing time
Reduces discomfort for patients and enables mobility and earlier discharge
Reduced treatment costs
Patient more likely to receive antibiotic at correct time
Potential to reduce risk of adverse effects
Most infections respond to 5-7 days treatment according to severity
How long should you treat,UTI, streptococcal pharyngitis, pulmonary tuberculosis and endocarditis
UTI 3 days
Streptococcal pharyngitis 10 days
Pulmonary tuberculosis 6 months
Endocarditis 5 weeks
Outpatient parenteral antimicrobial therapy (OPAT)
Let’s people be treated in their own home
Reduces risk of acquisition of nosocomial infections
But can develop others like drug toxicity or line infections, failure to resolve underlying condition
What is sepsis
- Microbial invasion
- Systemic inflammation (cytokines mediated, hypothalamus involved)
- Organ dysfunction (e.g. inflammation happens somewhere it shouldn’t, like joints)
Death from multi-organ failure
Hypothermia can be a sign
Describe the clinical definition for sepsis in
Temperature
HR
RR
WBC
Note that SIRS (systemic inflammatory response) is not specific for infection or organ dysfunction. Need 2+ of above
Temp >38 or <36
HR >90/min
RR >20/min
WBC >12x10^6/ml or <4x10^6/ml
Define bacteraemia
What is septicaemia
Presence of micro-organisms in bloodstream
May be transient (e.g. dental procedures)
May be terminated by host immune system
Bacteraemia and sepsis = septicaemia
What does the cytokines cascade cause in sepsis?
Clotting activation (disseminated intravascular coagulation) Oxidative stress (circulatory compromise) Increased endothelial permeability (impaired pulmonary function) Autonomic NS activation (inadequate organ perfusion)
Common causes of sepsis are listed below, name the common organisms that cause them
UTI Pneumonia Skin/soft tissue/bone Meningitis Intra-abdominal infection Infective endocarditis
UTIx e.coli
Pneumonia- s.pneumoniae
Skin/soft tissue/bone- s.aureus, s.pyogenes
Meningitis- n.meningitidis
Intra-abdominal infection- e.coli
Infective endocarditis- streptococci and s.aureus
Infective endocarditis is a bacterial infection on heart valves. When pumped into the blood, they can go to many places around the body.
Describe the risk factors of infection
Valvular disease Prosthetic valve Intravenous drug use Central lines Implantable cardiac devices
S.pyogenes is a common cause of tonsillitis and scarlet fever. What is it sensitive to and what antibodies does it activate
Penicillin sensitive
Antistreptolysin O antibodies (ASOT) rise after tonsillitis
Antibody cross-reactivity following s.pyogenes infection can cause rheumatic fever.
What does this cause?
Damage to connective tissue
Fever, poly arthritis, carditis
Untreated repeat attacks can cause valve damage
List the presentation of infective endocarditis and signs
Fever, lethargy, emboli infection
Signs
New murmur, skin lesions from emboli (Roth’s spots, oslers nodes)
List the diagnosis and management of infective endocarditis
Duke’s criteria (microbiology or cardiology)
Management
High dose IV antibiotics
BSAC guidelines
May need valve replacement
List the common syndromes of hospital onset sepsis
Central/peripheral lines)
Urinary catheters
Pneumonia (ventilator associated)
Post-op wound infections
In sepsis, what should you do before antibiotic prescription?
Bloods (include lactate)
High lactate identifies patients at risk who may not be hypotensive
Microbiology (take 2 blood cultures, infection specific samples-urine, CSF, and pus swab in universal)
Broad spectrum antibiotic on outset, oxygen, fluid in and out
What is synergistic with vancomycin for MRSA?
Rifemipicin
Patient is examined for a cardiac murmur after initial management, why?
Organs affected for sepsis
List the risk factors for resistant organisms
Frequent hospital admission Prolonged stay in intensive care Hospital stay overseas Nursing home resident Previous carriage Previous antibiotic use
What should occur in a sepsis follow-up
Important to find source
Assess risk of recurrence
Exclude endocarditis/intravascular source if:
Persistent bacteraemia despite treatment
Multiple sites of infection
Specific signs of endocarditis
Monitor bloods (inflammatory markers, therapeutic drug monitoring and kidney function)
what are the six indicators of high risk ‘red spesis’
New objective confusion Oliguria RR >25 or new O2 reqt >40% Pulse >130 or systolic BP <90 Skin - mottled, cyanosis Lactate >2mmol/L
What is included in the sepsis 6 bundle
Oxygen Blood cultures (2) and bloods Check lactate IV antibiotics <1 hour Fluids- give and monitor Senior review/critical care
