Antibiotics in cardio-respiratory infections Flashcards
Name some upper respriatory tract symptoms
- sinustitis
- ottis media
- rhinitis
- tonillitis
- pharyngitis
What is the common microogranisms that is in the upper respriatory tract
- normal flora such as viridans streptococci
- temporary colonisers such as staph aureus and candida
- pathogens
Name a organisms in the normal flora of the upper respiratory tract
viridans streptococci
Name some temporary colonisers of the upper respiratory tract
staph aureus and candida
Name some common bacteria in the URTI
= Strep pyogenes = group A
= strep pneumoniae
= haemophilus influenzae
Name 7 common URTI viruses
- rhinovirus
- influenza/parainfluenza
- cornavirus
- adenovrius
- RSV = respiratory syncytial virus
- Coxsackie
- enterovirus
what are uncommon causes of URTI
- corynebacterium diphtheriae
- nisseria menigitidis
What are the symptoms of influenza
- fever
- coryza
- systemic symptoms - headache, malaise, myalgia, arthralgia, and GI symptoms
What defines an influenza as complicated
Requires hospital admission
and/or
- pneumonia/hypoxaemia
- CNS - menigitis
- Exacerbation of co-morbdity
How do you treat complicated influenza
if the perosn is not severely immunosupressed
- 1st line is = oseltamivir, PO/NG
- 2nd line = zanamivir iNH, NEB or IV
How do you treat uncomplciated influenza
If they are previously healthy
- No treatment
or
- oseltamivir PO if physician feels patietn is a serious risk of developing complciations
If they are in an at risk group
- Are they severely immunosupressed
If no to immunosupressed
- oseltamivir PO within 48 hours of onset or later at clinical discretion
How do you prevent influenza
- Vaccinations of patients
How do you investigate influenza
- Primary care - not needed
- secondary care - nasopharygneal swab for flu PCR
in influenza you should not
- confirm the infection before treating
What is the treatment for influenza
- within 48hr of start of symptoms
- oseltamivir 75mg bd oral/NG x 5 days
What bacteria causes pharyngitis
- Group A, B, C streptococci
- Mycoplasma pneumoniae
- Neisseria gonorrhoea
- Corynebacterium diptheriae
What is the most common bacteria that causes pharyngitis
Group A streptococci
What virus can cause a pharyngitis
- 7 common URTI viruses
- EBV
- CMV
- HSV
- Measles, HIV etc
Is bacteria or virus most common cause of pharyngitis
Virus
What are the symptoms of scarlet fever
- sore throat, fever, felt ill
- tonsillar exudate
- tender cervical nodes
How do you treat scarlet fever
- Penicillin V for 10 days
What criteria is used to help GPs if patients benefit from antibitoics for pharyngitis
Centor criteria
How do you work out the centor criteria
One point for
- tonsillar exudate
- tender cervical lymph noes
- absence of cough
- fever
if 1 or 2 points there is a 20% chance of Group A Strep - no anitbotics is given
if 3 or 4 point there is a 50% chance of Group A Strep - antibitoics are given
How do you treat Group A Strep
- all are penicillin senstiive
- majority erythromycin senstiive - for penicillin allergic people
- penicillin V 500mg QDS or 1g BD for 5-10 days OR clarithromycin 500mg BD for 5 days
What are the complications for group A strep
- rheumatic fever
- glomerulonephritis
What are the symptoms of EBV
- sore throat, fever, felt ill
- tonsillar exudate
- tender cervical nodes
How do you treat EBV
penicillin V (or clarithromycin)
If you give amoxicillin to an EBV patient what can happen
amoxicillin frequently causes a rash in patients with EBV
DO NOT GIVE AMOXICILLIN FOR
SORE THROAT
What causes otitis media virus or bacteria more?
Virus
What bacteria can cause otitis media
- Streptococcus pneumoniae
- Haemophilus influenzae
- Moraxella catarrhalis
- Mycoplasma pneumoniae
- Streptococus pyogenes
How do you treat otitis media in children
No anitbiotics unless
- under 2 years
- symptoms persist longer than 48 hours
- high fever
- bilateral
- otorrhea
What antibitoics is used for otitis media for children
- Amoxicillin for 5-7 days
- clarithromycin for 5-7 days
in adults otitis media is more likely to be
bacterial than viral
How do you treat otitis media in adults
- Amoxicillin
- Clarithromycin
What complications do you get in otitis media that is untreated
- decreased hearing
- mastoditis
- brain abscess
is it bacteiral or viral that causes sinustitis more
Virus
What is the bacterial cause of sinusitis
- Streptococcus pneumoniae
- Haemophilus influenzae (unencapsulated)
- Moraxella catarrhalis
How do you treat sinustitis
Treatment is not usually as it is viral
but if it is bad
- consider penicilin V or clarithromycin
- Co-amoxiclav if systemically unwell
Name the lower respiratory tract infections
- Pneumonia
- Chronic bronchitis
- Bronchiectasis and cystic fibrosis
- emphysema
What are the types of pneumonia
Community acquired
- typical
- atypical
Hosptial acquired
Aspiration
What are the two types of community acquired pneumonia
- Typical
- Atypical
what are the causes of typical penumonia
- strep pneumoniae
- haemophilus influenzae
- staph aureus
What are the causes of atypical pneumonia
- Mycoplasma pneumoniae
- Legionella
- Chlamydia
pneumoniae - Chlamydia psittac
What are the risk factors for pneumoccoal pneumonia
- Influenza
- Alcohol
- Smoking /COPD
- HIV
What is the most common cause for pneumonia
Pneumoccoal pneumonia
What are the first line and 2nd line antibitoics for strep pneumoniae (pneumococcal pneumonia)
1st line
- amoxicillin
- doxycycline
- leveofloxacin
2nd line
- ceftriazone
- tecioplanin
- vancomycin
What should you always ask in the history of someone with pneumonia
- Take a travel history as if they picked up the pnemonia from another country they could be resistant to certain antibiotics
what are the two main causes of atypical pneumonia
- Mycoplasma pneumoniae
- legionella species
why is Mycoplasma pneumoniae not visible on gram stain
- Has no cell wall
- therefore not visible on gram stain
- therefore unaffected by cell wall antibitoics
When does myoplasma pneumoniae typically act
- autumn to winter
- casues a dry cough
What do patients with myoplasma pneumoniae present with
- Dry cough
- +/- pharyngitis, rhinorrhea, otalgia
- +/- hepatitis, meningitis
What antibitoics do you use for mycoplasma pneumonia
- Macrolides (clarithromycin or erythromycin)
- Quinolones (levofloxacin)
- tetracyclines (doxycycline)
describe the structure of legionella spp (penumonia cause)
- Gram negative rods
- Require special media for growth
- Slow growth (3-5days)
What is the most common type of legionella spp
L pneumophila
How do you treat legionella spp causing pneumonia
- Cell wall antibiotics clinically not effective
- Quinolones >Macrolides>tetracyclines effective
What are the risk factors of S aureus penumonia
More comon
- colonisation of URT
- Viral URT
what does a PVL-toxin strains in s aureus penumonia cause
- Severe disease
- necrotising/abscess formation
what is treatment of pneumonia based on
CURB65
Describe the different part of the scores that make up the CURB65
- Confusion
- Urea greater than 7mmol/l
- Respiratory rate greater than 30/min
- Blood pressure hypotensive
- aged over 65
Score
- 0-1 = low severity, risk of death is less than 3% so treat as an outpatient
- 2 = moderate severity, risk of death is 9%, admit, have microbioloigcal investigations, IV antibitoics
- 3-4 = high severity, risk of death is 15-40%, urgent admission
What is the negative to do with the CURB65 score
- may underestimate how severe pneumonia is in someone who is young as they tend to have there blood pressure controlled until they are really ill
What is the treatment used for pneumonia based on the CURB 65 score
- 0-1 : Oral amoxicillin 500mg TDS OR doxycycline 100mg OD
- 2 : IV benzylpenicillin 1.2g QDS & doxycycline 100mg BD
- > 2 : IV Co-amoxiclav 1.2g TDS & doxycycline 100mg BD
OR IV ceftriaxone 2g OD & doxycycline 100mg BD
What is hospital acquired pneumonia
- pneumonia that develops 48 hours after admission or within 2 weeks of admission
hospital acquired pneumonia is
3rd commonest nosocomial infection but has the highest mortality
What are the predisposing factors for hospital acquired pneumonia
- Abnormal conscious state/ intubation and ventilation
- immunosuppresion
How do you treat hospital acquired pneumonia
Mild/moderate
– doxycycline
Severe
○ Early onset (<5 days) – co-amoxiclav
○ Late onset (>5 days)- piperacillin-tazobactam
what is the microbiology for hospital acquired pneumonia comapred to community
- hospital acquired also includes gram negative organisms such as E.coli, Klebsiella and pseudomonas
What causes aspiration pneumonia
- can involve bacteria from the upper respiratory tract or stomach - usually low virulence
can be polymicrobial
- invovles aerobic streptococci and anaerobes
How do you treat aspriation pneumonia
- Amoxicillin & metronidazole(need anaeorbe cover from metronidazole)
- Levofloxacin & metronidazole (need anaeorbe cover from metronidazole)
- Co-amoxiclav - has got anaerobe activity in it
- Piperacillin-tazobactam - has got anaerobe activity in it
What is ECOPD
- Exacerbation of COPD
What are the symptoms of ECOPD
Worsening of symptoms
- shortness of breath
- cough
- sputum
What are the triggers for ECOPD
- viruses
- bacteria
- pollution
- CCF (congestive cardaic failure)
- VTE
- aspriation
- in a 1/3rd of cases it is not known
What are the bacterial causes of ECOPD
- Haemophilus influenzae
- moraxella catarrhalis
- streptococcus pneumoniae
- pseudomonas aeruginosa
- chlamydia pneumniae
What are the viral causes of ECOPD
- Rhinovirus
- influenza/parainfluenza
- adenovirus
- RSV
- metapneumovirus
- coronavirus
What are antibotics only effective in ECOPD
if they have a history of 2 or more of
- increased dyspnoea
- increased sputum purulence
- increasd sputum volume
What is the treatment of ECOPD
- Doxycycline or clarithromycin
- duration of treatment is 5 days
- if relapse/recurrence within 3 months then antibotics with alternative agent
- if consolidation on CXR then treat as for CAP/HAP
What is bronchiectasis
- abnormal dilatation of the major bronchi and bronchioles
- chronic daily cough with viscid sputum production
- on CT see bronchila wall thickening and luminal dilatation
What is cystic fibrosis
- congenital
- abnormal secrtions resulting in chronic infections and bronchiectasis
What organisms can caue bronchiectasis
- Viral
- Haemophilus influenzae
- Moraxella catarrhalis
- Staph aureus
- Strep pneumoniae
- Pseudomonas aeruginosa
How do you treat bronchiectasis
- If no pseudomonas – Rx clarithromycin or doxycycline or co-amoxiclav
- If pseudomonas – Rx po ciprofloxacin or IV pip-taz
What is the prophyalxis for bronchiectasis and cystic fibrosis
- Chest physiotherapy /postural drainage
Oral azithromycin
- For recurrent exacerbations only
- After excluding non-tuberculous mycobacterial infection
Inhaled abx
- Nebulised gentamicin, tobramycin, colistin
What is empyema
complicated parapneumonic effusion
what is parapneumonic effusion
effusion into the pleural space adjacent to bacterial pneumonia
How do you treat a normal parapneumonic effusion
- resolve with treatment of pneumonia
What happens in complicated parapneumonic effusion
- Bacteria invade pleural space
- Empyema develops
How do you treat empyema
Drainage
- Antibiotics until XR resolution
- Usually 2-4 weeks
What diseases can you get vaccinations to
- Influenza
- Pneumococcal
- Haemophilus influenzae
- Pertussis
- Diptheria
where can infective endocarditis occur on
- normal valves
- abnormal native valves
- prosthetic valves
in infective endocarditis the
site determines the likley organism
On a normal native valve what are the organisms that cause infective endocarditis
High virulence
- Staphylococcus aureus
- strep pneumoniae
What are the risk fators for infective endocarditis on a normal valve
infected cannulae
- normaly S aureus
IVDA (IV drug abuse) - often leads to right sided endocarditis
- S aureus
- Yeasts
- Pseudomonas spp
What causes infective endocarditis in an abnormal native valve
- rheumatic fever
- degenerative (calcific) disease
- congenital defects (especially turbulent flow)
- mitral valve prolapse (5-10 x risk)
What bacteria causes infective endocarditis
infection due to low virulence bacteria
- oral streptococci
- endterococcus spp
- HACEK group of organisms
- occasionally - coxiella burnetti, chlamydia spp, mycoplasma spp, bartonella spp
What causes infective endocarditis in the prosthetic valve in the 1st year after surgery
- in first year after surgery risk is 1-2%
commonly - Stap aureus - immediately post op
- coagulase negative staphylococci - later presentation
What causes infective endocarditis in the prosthetic valve in the after 1st year post surgery
- risk is 0.5%
Commonly - oral streptococci
- enterococcus spp
What is the treatment of infective endocarditis
- Vegetation is hard to treat as it is impenetrable by phagocytoes
- surgicial backup is essential
- IV therapy is essentila - 4 weeks native valve IE, 6 weeks prostehtic valve IE
- need to know what bug is causing it
What are the two types of antibitoic senstivity teting
- Disc diffusion tests
- MIC tests (E-test)
What is a disc diffusion test
- qualitative measurement to see if it is sensitive or resistant
- uses an ajar plate - put on a paper disc that has antibiotic in it
- over 12-24 horus the anitbiotic goes over the plate and kills bacterai that is senstivie to it
How does MIC test work
- on agar plate place a paper strip that has antibitoic on it
- at the top of the strip there is the highest concentration of antibitoic and as you go down the antibiotic concentration decreases
- tells you how much anitbioitc is required to kill the microorganisms
- quantitative measurement to see how sensitive/resistant the microorgansim is
What does MIC stand for
- minimum inhibitory concentration
- lowest concentration of an antimicrobial that will inhibit the visible growth of a microorganism after overnight incubation
What does MBC stand for
- minimum bactericidal concentration
- lowest concentration of antimicrobial that will prevent the growth of an organism after subculture on to antibiotic-free media.
- dont really use in clinical practise
What is the treatment for infective endocarditis on the native and prosthetic valve
Native
- Vancomycin and gentamicin
- or vancomycin and meropenem (if risk of gram negative spesis)
Prosthetic
- vanocmycin and gentamicin and rifampicin
- 6 week course
- poor prognosis
- add oral rifampicin to treat biofilm
What do you use to treat each of these microorganisms in infective endocarditis
- Staphylococcus
- streptococci
- enterococci
Staphylococcus
- Flucloxacillin - 4 hourly
- MRSA - vancomycin
Streptococci
- Benzylpenicillin 4 hourly
- If pencillin resistance - vancomycin and gentamicin
Enterococci
- amoxicillin 4 hourly and gentamicin
What is a biofilm
a cluster of bacteria in an extracellular matrix (slime) attached to a surface
describe how a biofilm forms
- adhesion to the surface
- formation of monolayer and production of slime
- microcolony formation with multi layering cells
- mature biofilm with characterstic mushroom formed of polysaccharide
