Chapter 5: Infection Flashcards
What aminoglycosides are active against Pseudomonas and what one is the treatment of choice?
Gentamicin - treatment of choice
Amikacin
Tobramycin - usually via inhalation in CF
What aminoglycoside is active against TB?
Streptomycin
mainly reserved for this indication
Can aminoglycosides be given orally?
No- destroyed by gut => must be given via injection
Is gentamicin a broad or narrow antibiotic?
What strains does it have poor activity against?
Broad but inactive against anaerobes and poor activity against haemolytic streptococci and pneumococci
Very good for gram -ve organisms
Which aminoglycoside is used for endocarditis?
If it is resistant to this, what is an alternative aminoglycoside?
Gentamicin <3 plus another antibiotic
Streptomycin is an alternative if resistant to gentamicin
Are aminoglycosides more active against gram positive or gram negative?
Gram negative but are broad
Can neomycin be given IV?
No - too toxic.
Can only be used for skin/mucous membrane infections. However BNF: cream less suitable for prescribing
Can also be used to reduce bacterial population of the colon prior to bowel surgery or in hepatic impairment
What is the problem with using aminoglycosides in myasthenia gravis?
Contraindicated
May impair neuromuscular transmission
What antibiotics can be used for prophylaxis in rheumatic fever?
Pen V or sulfadiazine
What anitbiotics can be used for prevention of secondary case of menincoccal meningitis?
Ciprofloxacin or rifampicin
Or IM ceftriaxone (unlicensed)
What antibiotic can be used for prevention of secondary infection for Group A strep?
Pen V
What antibiotic can be used for prevention of secondary infection in Influenza Type B?
MOA?
Rifampicin
Antimycobacterial; inhibits bacterial DNA-dependent RNA synthesis by inhibiting bacterial DNA-dependent RNA polymerase.
What antibiotic can be used for prevention of secondary cases of diphtheria in non-immune patients?
Erythromycin
What would you treat gonorrhoea with?
1st:
- Unknown antimicrobial: IMceftriaxone.
- If micro-organism sensitive to ciprofloxacin: oralciprofloxacin.
2nd: alternative to allergy/needle phobia/CI
- IMgentamicin+oralazithromycin.
3rd: If parenteral administration is not possible:
- oralcefixime[unlicensed]+oralazithromycin.
What antibiotic is used for prophylaxis of pertussis (whooping cough)?
Clarithromycin
What antibiotic is used post splenectomy or in patients with sickle cell disease for prevention of pneumococcal infection?
Pen V
Erythromycin if penicillin allergic
What antibacterial prophylaxis/treatment is used in animal and human bites?
If the patient is penicillin allergic, what should be used instead?
Co-amoxiclav
(co-species)
If penicillin allergic: Doxycycline and metronidazole
Up to 5 days and give tetanus jab
What antibacterial prophylaxis do you use in hip and knee replacement?
Single dose IV cefuroxime/flucloxacillin
Add in gentamicin
What antibacterial prophylaxis do you use in high lower limb amputation?
Use IV co-amoxiclav alone
or
IV cefuroxime + IV metronidazole
What antibacterial prophylaxis do you use in caesarean section?
Single dose cefuroxime
What is 1st line for aspergillosis?
What is 2nd line if this cannot be used?
Voriconazole
Liposomal amphotericin
If a patient with aspergillosis is intolerant/refractory to voriconazole and liposomal amphotericin, what other antifungals can be used?
Caspofungin
Itraconazole
3rd line: posaconazole
What systemic antifungal is used in vaginal candidiasis?
For resistant organisms, what can be used?
Fluconazole
Itraconazole as an alternative
What is micafungin licensed for?
CANDIDIASIS
- Invasive candidiasis
- Oesophageal candidiasis
- Prophylaxis of candidiasis in patients undergoing haematopoietic stem cell transplantation
Cryptococcal meningitis, a fungal infection, is especially common in which group of immunocompromised patients?
How is this treated?
HIV positive
IV amphotericin followed by PO fluconazole
What is tinea capitis?
Fungal infection (ringworm) of scalp
What is tinea pedis?
Athlete’s foot
How do you treat tinea capitis?
Systemically - Griseofulvin
Can also used an additional topical application
True or false:
In fungal nail infections, topical therapy is more effective than systemic
False
Systemic is more effective
Is fluconazole active against Aspergillus?
No
Is caspofungin effective against CNS fungal infections?
No
What is the advantage of lipid amphotericin formulations over conventional amphotericin?
Significantly less toxic but also £££ expensive £££
Recommended when the conventional formulation of amphotericin is CI because of toxicity, esp. nephrotoxicity or when response to conventional amphotericin is inadequate
What are echinocandin antifungals active against? (Caspofungin, micafungin)
Aspergillus and Candida
Not active against CNS fungal infections
What can be used for MRSA?
- main class
- alternatives
- soft or skin tissue infections
- bone and joint
Glycopeptides mainly: Teicoplanin and vancomycin
Alternatives: Tigecyline, Daptomycin
Linezolid (if glycopeptide unsuitable)
Tetracyclines can be used for skin or soft tissue infections or UTI caused by MRSA
Clindamycin can be used for bone and joint MRSA infections
Are carbapenems useful against MRSA?
No
Do carbapenems have good activity against pseudomonas? What is the exception to this?
Yes apart from ertapenem
Why does imipenem have to be administered with cilastatin?
Imipenem is partially inactivated in the kidney by enzymatic activity and is administered in combination with cilastatin, a specific enzyme inhibitor, which blocks its renal metabolism.
If meningitis is suspected, what antibiotic should be given before being transferred to hospital (as long as this doesn’t delay treatment)?
What would be an alternative?
IV benpen
Cefotaxime if penicillin allergic
Chloramphenicol if history of immediate hypersensitivity to penicillin and cephalosporins
When would you use dexamethasone in meningitis?
In what situations would you avoid this?
Particularly in pneumococcal meningitis in adults, either before starting antibacterial therapy or within 12 h of starting.
Avoid using in septic shock, mening. septicaemia, immunocompromised, or meningitis following surgery
What is the recommended antibiotic therapy for children 3 months - adults 50 years in meningitis if the cause is unknown?
What is the suggested duration of treatment?
Cefotaxime / ceftriaxone
Consider adding vancomycin
10 days
What is the recommended antibiotic therapy for adults over 50 years in meningitis if the cause is unknown?
What is the suggested duration of treatment?
Cefotaxime / ceftriaxone AND amoxicillin / ampicillin
Consider adding vancomycin
10 days
What is the recommended antibacterial therapy for meningitis caused by meningococci (neisseria)?
What would be an alternative if not suitable?
What is the suggested duration of treatment?
Benpen
Or cefotaxime/ceftriaxone
Chloramphenicol is an alternative if history of immediate hypersensitivity to penicillins or cephalosporins
7 days
What bacteria can be the cause of meningitis? (4)
Meningococcal (neisseria)
Pneumococcal
Haemophilus influenzae
Listeria
What is the recommended antibacterial therapy for meningitis caused by pneumococcal?
If the organism if penicillin and cephalosporin resistant, what can be added?
What is the suggested duration of treatment?
IV Cefotaxime / ceftriaxone
Consider adding dex before first dose or within 12 hours of starting antibacterial therapy
If penicillin sensitive, change to Benpen*
If penicillin and cephalosporin resistant, vancomycin and rifampicin can be added
14 days!
What is the recommended antibacterial therapy for meningitis caused by Haemophilus influenzae?
What is the suggested duration of treatment?
Cefotaxime / ceftriaxone
Consider adding dex before first dose or within 12 hours of starting antibacterial therapy
10 days
What is the recommended antibacterial therapy for meningitis caused by Listeria?
What is the suggested duration of treatment?
If history of immediate penicillin hypersensitivity, what could be an alternative?
Amox/ampicillin AND gentamicin
21 days - can consider stopping gentamicin after 7 days
Alternative- co-trimoxazole for 21 days
How should the following be managed:
Patients presenting with sinusitis symptoms of 10 days or less
Paracetamol, ibuprofen, nasal saline
Antibiotics not usually required
How should the following be managed:
Patients presenting with sinusitis symptoms of 10 days or more
Consider high-dose nasal corticosteroid; mometasone [unlicensed use] or fluticasone [unlicensed use] for 14 days.
Back-up antibiotic can be issued if symptoms do not improve within 7 days
In what situations would you offer antibiotics for sinusitis?
Should only be offered to patients with acute sinusitis who are SYSTEMICALLY UNWELL, have signs and symptoms of a more serious illness OR if bacterial sinusitis is suspected.
- Streptococcus pneumoniae,
- Haemophilus influenzae,
- Moraxella catarrhalis, and
- Streptococcus pyogenes
What is 1st and 2nd line in a non-penicillin allergic sinusitis patient if antibiotics are indicated?
1st line- Pen V
2nd line- Co-amox
especially if more serious illness
What is 1st line in a penicillin allergic sinusitis patient if antibiotics are indicated?
Doxycycline or clarithyromycin
What is 1st line in a penicillin allergic sinusitis PREGNANT patient if antibiotics are indicated?
Erythromycin
What antibiotic can be used in a pregnant UTI patient?
Cefalexin
If antibiotics are clinically appropriate, what would be used for otitis externa?
What if the patient is penicillin allergic?
Flucloxacillin
Clarithromycin
If antibiotics are clinically appropriate, what would be used for otitis media?
What if the patient is penicillin allergic?
Amoxicillin (or co-amox as second line)
Clarithromycin
What antibiotics are likely to cause C.Diff?
Clindamycin
Penicillins
Cephalosporins
Fluoroquinolones
What 3 antibiotics can be used in C.Diff?
Vancomycin
Metronidazole
Fidaxomicin
For first episode of mild-moderate C.Diff, what should be used and for how long?
Oral metronidazole for 10-14 days
For second/subsequent C.Diff infection not responding to metronidazole, what can be used and for how long?
Oral vancomycin
Fidaxomicin can be used for severe infection
10-14 days
What antibiotic is used for bacterial vaginosis and how long for?
Metronidazole 5-7 days
What antibiotics cover chlamydia? AED
Azithromycin (single dose)
Doxycycline
Erythromycin
What would you use to treat gonorrhoea?
If the IM route is not possible, what would you use instead?
- If unknown species IM 1g ceftriaxone
- If sensitive to cipro, oral ciprfloxacin 500mg
- Alternative for allergy, contraindication or needle phobia: IM Gentamicin + oral Azithromycin
- If IM route not possible oral Cefixime+ Azithromycin
What is the recommended length of treatment for osteomyelitis?
6 weeks
Osteomyelitis and septic arthritis antibiotic choice:
- First line
- If penicillin allergic
- If MRSA suspected
- Flucloxacillin
- Clindamycin
- Vancomycin or teicoplanin
What penicillins can you use for oral infections e.g. dental?
Pen V / Amoxicillin
However these are not effective against bacteria that produces beta lactamases
Co-amox can be used in severe cases
What is drug of choice for acute ulcerative gingivitis?
Metronidazole
What is the recommended therapy for Haemophilus influenzae?
Cefotaxime / ceftriaxone
What antibiotics do you use to treat an acute exacerbation of chronic bronchitis and how long for?
Amoxicillin or a tetracycline for 5 days
What antibiotic therapy is recommended in low severity CAP and how long for?
CRB65 score 0, or CURB65 score 0 or 1
What would be alternatives?
1st choice: Amoxicillin 500 mg TDS orally or IV
4 for 5 days in total
Alternative antibiotics
- Clarithromycin 500 mg BD or IV
4 for 5 days in total
- Erythromycin (in pregnancy) 500 mg QDS for 5 days
- Doxycycline 200 mg on first day, then 100 mg once a day orally for 5 days
CAP
- start tx within 4 hrs
- within 1 hr if sepsis suspected
- CRB65 or CURB65
LOW severity = Oral 1st line: Amoxicillin.
- Alt pen allergy; clarithro, doxy, or erythro (preg).
MODERATE severity = Oral 1st line: Amoxicillin.
- Atypical pathogens sus: Amox + Clari / Erythro (preg).
- Alt pen allergy; clarithromycin, or doxy.
HIGH severity = Oral or IV 1st line:
Co-amoxiclav + clarithromycin / oral erythromycin (preg).
- Alt pen allergy: levofloxacin (consult local microbiologist if fluoroquinolone not appropriate).
What antibiotic therapy is recommended in high severity CAP and how long for?
CRB65 score 3 or 4, or CURB65 score 3 - 5
High severity; Oral or IV 1st line:
Co-amoxiclav with clarithromycin or oral erythromycin (in pregnancy).
Alternative in penicillin allergy: levofloxacin (consult local microbiologist if fluoroquinolone not appropriate).
5 days
If MRSA suspected, add teic/vanc
CRB 65 or CURB 65 used when and where?
CURB-65 mortality risk score (hospital setting) or CRB-65 severity score (community setting)
- Confusion
- BUN > 19 mg/dL (> 7 mmol/L)
- Respiratory Rate ≥ 30
- Systolic BP < 90 mmHg or Diastolic BP ≤ 60 mmHg
- Age ≥ 65
If MSRA was suspected in CAP, what would you add on to the treatment?
Teic/vanc
What are the main organisms that cause pneumonia?
Streptococcus pneumoniae Chlamydia pneumoniae Haemophilus influenzae Mycoplasma pneumoniae Legionella pneumophila
What would you use to treat pneumonia caused by chlamydial/mycoplasma?
Doxycycline
What is the difference between early onset vs late onset HAP (in terms of days in hospital)?
Early onset = < 5 days admission to hospital
Late onset = > 5 days after admission to hospital
How do you treat HAP?
- non severe signs/symptoms within 3-5 days of hospital admission and not at ^risk resistance
- Severe signs/symptoms or at ^ risk of resistance
Non-severe signs/symptoms & not at ^!!resistance:
- Oral 1st line: Co-amoxiclav.
- Alt pen alergy; doxycycline, cefalexin (caution in penicillin allergy), co-trimoxazole [unlicensed], or levofloxacin [unlicensed]
Severe signs or symptoms or at higher risk of resistance
- IV 1st line: Piperacillin with tazobactam, ceftazidime, ceftazidime with avibactam, ceftriaxone, cefuroxime, levofloxacin [unlicensed], or meropenem.
- MRSA confirmed/sus: add vancomycin, or teicoplanin, or linezolid
What would you use to treat a small area of impetigo?
Fusidic acid
What would you use to treat impetigo?
If penicillin allergic, what would be an alternative?
1. TOPICAL; hydrogen peroxide 1% local. => fusidic acid => resistant? mupirocin. 1. ORAL 1st line: Flucloxacillin. Alternative if pen allergy or flucloxacillin unsuitable: clarithromycin or erythromycin (in pregnancy).
What would you use to treat cellulitis?
If penicillin allergic, what can be used?
High dose flucloxacillin
Clindamycin/clarithromycin
What antibiotic would you use for mastitis during breastfeeding?
What if penicillin allergic?
Flucloxacillin
Pen allergic => Erythromycin
10-14 days
What are the side effects of aminoglycosides?
OTOTOXICITY - report tinnitus, hearing loss, vertigo
NEPHROTOXICITY
May impair MUSCLE transmission-c/i in myasthenia gravis
What is the risk of aminoglycosides to the infant in pregnancy?
Risk of auditory or vestibular nerve damage
What is a possible problem with carbapenems that means it is cautioned in CNS disorders?
Seizure inducing potential
Also ^ risk of seizures if renal impairment
imipenem-cilastatin, meropenem, ertapenem, doripenem, panipenem-betamipron, and biapenem.
Should you give carbapenems if there is a history of immediate hypersensitivity to penicillins?
No
True or false:
Cephalosporins penetrate the meninges poorly unless they are inflamed
True
What are some common side effects of cephalosporins?
Abdominal pain
Eosoniphilia
Thrombocytopenia
Should you give cephalosporins if there is a history of penicillin allergy?
Used in caution
But should not be given if there is immediate hypersensitivity
What are the glycopeptide antibiotics?
Dalbavancin, Teicoplanin, Telavancin, Vancomycin
- inhibits bacterial cell wall formation by inhibiting peptidoglycan synthesis. Used for treating MRSA infections and enterococcal infections, which are resistant to beta-lactams and other antibiotics.
Which of the following antibiotics has a lower incidence of nephrotoxicity:
Teicoplanin
Vancomycin
Teicoplanin
What drugs are associated with red man syndrome?
Red Man Syndrome an anaphylactoid reaction caused by the rapid infusion of
Glycopeptides;
Teicoplanin
Vancomycin
What is the main advice to give to patients on clindamycin [lincomycin] and should stop taking if this happens?
Diarrhoea
Stop and contact doctor
What are the cautions in macrolides?
QT prolongation
and electrolyte disturbances
- clarithromycin, erythromycin, azithromycin
Amoxicillin can cause an increased risk of erythematous rash in what conditions?
Acute lymphocytic leukaemia
Chronic lymphocytic leukaemia
CMV
Glandular fever
Why should you maintain adequate hydration with high doses of IV amoxicillin?
Risk of crystalluria especially in renal impairment
What is the dose of amoxicillin in susceptible infection for a child 1-11 months?
125mg TDS
increased up to 30mg/kg TDS if needed
What is the dose of amoxicillin in susceptible infection for a child 1-4 years?
250mg TDS
increased up to 30mg/kg TDS if needed
What is the dose of amoxicillin in susceptible infection for a child 5-11 years?
500mg TDS
increased up to 30mg/kg TDS if needed
What is the dose of amoxicillin in susceptible infection for a child 12-17 years?
500mg TDS
Increased up to 1g TDS if needed
What is the dose of amoxicillin in susceptible infection for an adult?
500mg TDS
What is the MHRA warning surrounding flucloxacillin?
Cholestatic jaundice and hepatitis
What is a side effect of oral amoxicillin and co-amox in terms of colouring the patient’s tongue?
Black hairy tongue
Ciprofloxacin is a type of what antibiotic?
Quinolone
What is the important safety information regarding fluoroquinolones?
CONVULSIONS; taking NSAIDs may also induce them.
TENDON damage (including rupture) may occur within 48 h of starting treatment
Small increased risk of aortic aneurysm and dissection
Should quinolones be used in MRSA?
No
What quinolone is active against pseudomonas?
Ciprofloxacin
What are some common side effects of quinolones?
QT prolongation
Hearing impairment
Decreased appetite
Rhabdomylosis
Drug should be discontinued if psychiatric, neurological reactions occur
Cautioned in young adults and children- risk of arthropathy (joint disease)
What antibiotic would you use for PCP prophylaxis and treatment?
Co-trimoxazole
PCP = pneumocystitis carinii pneumoneai
What is a rare but serious side effect of co-trimoxazole?
Blood disorders
Rash - steven johnson’s syndrome
What age group are tetracyclines contraindicated in?
Children < 12 due to deposition in growing bones and teeth ; Staining of teeth can occur
What are the common side effects of tetracyclines?
doxy, mino, tiga, tetra
Can they be taken with dairy products?
Angiodema
Henoch Schonlein purpura (spotty rash)
Photosensitivity rxn
Headaches and visual disturbances- may indicate benign intercranial hypertension - discontinue if intercranial pressure increases
Dairy products decrease the exposure to tetracycline—manufacturer advises take 1 hour before or 2 hours after dairy products.
Is there any special patient advice with doxycycline?
Should be taken with meals
Avoid exposure to sunlight and sun lamps
Do not take zinc, indigestion remedies 2 hours before or after
What is a serious SE of chloramphenicol when given systemically?
Haemotological side effects (agranulocytosis, bone marrow disorder)
Aplastic anaemia- reports of leukaemia
Should only be reserved for life-threatening conditions e.g. typhoid fever
What muscle side effect can daptomycin cause?
Myopathy; Report any muscle weakness and monitor creatine kinase if necessary
Need to monitor CK twice a week whilst on it
What monitoring requirements are needed for systemic fusidic acid?
Elevated liver enzymes, hyperbilirubinaemia and jaundice can occur with systemic use
Manufacturer advises monitor liver function with high doses or on prolonged therapy
What is the important safety information regarding linezolid? [oxazolidinone]
Severe optic neuropathy- report visual impairment
Blood disorders - thrombocytopenia, anaemia,
What food does linezolid interact with and why?
Tyramine-rich foods (such as mature cheese, salami)
Avoid consuming large amounts
Why? Linezolid is a reversible MAOI
Is linezolid active against gram-ve, gram+ve or both?
Gram +ve
What would be the maintenance dose of trimethoprim in an adult for UTI?
200mg BD
Can you use trimethoprim in renal impairment?
Can it cause any electrolyte disturbances?
Yes- monitor
May need to half normal dose eGFR <15 ml/min
Half dose after 3 days if eGFR 15-30 ml/min
can cause hyperkalaemia and hyponatraemia
What is the patient advice surrounding rifampicin?
May stain contact lenses RED
Report signs of LIVER disorder
May colour urine RED - harmless
How does rifampicin interact with hormonal contraceptives?
Effectiveness of hormonal contraceptives are reduced - alternative method needed
What antibiotics are used in the initial phase of TB treatment?
How long is treatment for?
Rifampicin Ethambutol (only in initial phase) Pyrazinamide (only in initial phase) Isoniazid with Pyridoxine - continue for 2 months initial phase - 4 months continuation phase (up to 10 months)
Streptomycin- hardly used but may be useful if resistant to isoniazid
How many antibacterials are used in the continuous phase of TB treatment and how long for?
2 - rifampicin and isoniazid (with pyridoxine hcl)
4 months
If someone is isoniazid, what else must be prescribed and why?
Pyridoxine (vitamin B6)
Prophylaxis of isoniazid-induced neuropathy
What treatment for TB should be given in pregnancy and breastfeeding?
RIPE for 2 months and then RI (Rifampicin and isoniazid) for a further 4 months
Should NOT be given streptomycin
DOT TB therapy should be offered to which groups of people?
Directly Observed Therapy should be offered to:
- History of non-adherence;
- Previously treated for TB;
- Are in denial of the TB; multidrug-resistant TB; major psychiatric / cognitive disorder;
- History of homelessness, drug or alcohol misuse;
- Are/been in prison the past 5 years;
- Are too ill to self-administer treatment;
- Request directly observed therapy.
In a patient with HIV and TB, starting antiretrovirals in the first 2 months of TB treatment can increase the risk of what?
Immune reconstitution syndrome
In patients with HIV and TB, how long should the TB treatment be for?
What is the exception to this?
6 months
If TB has CNS involvement, 12 months max
What is the general CNS TB treatment?
RIPE for 2 months and then RI (Rifampicin and isoniazid) for a further 10 months
Initial high dose of dexamethasone or prednisolone should be started at the same time and slowly withdrawn over 4-8 weeks
What would be the treatment regimen for latent TB?
Isoniazid for 6 months - recommended if interactions with rifampicin a concern
OR rifampicin and isoniazid for 3 months - recommended if hepatotoxicity a concern
A break in TB treatment of how many weeks is classed as a treatment interruption?
2 weeks