Infectious Diseases Flashcards
Which antibiotic groups work by Time above the MIC?
Beta lactams
Note: why beta lactams are giving at frequent dosing as opposed to higher doses
Which antibiotic group works as a concentration dependent killer (peak concentration)?
Aminoglycosides
Which antibiotic group works by AUC/MIC?
Vancomycin
Azithromycin
What is the mechanism of action of aminoglycosides?
Binds the 30s subunit
What is the mechanism of action of beta lactams?
Bind to penicillin binding
proteins (PBPs)
* Inhibit completion of
synthesis of peptidoglycans
* Leads to bacterial cell wall
lysis in dividing cells
What is the mechanism of action of augmentin?
Bind to the beta-lactamase enzyme of bacteria to inhibit it allowing Beta-lactam antibiotic to damage bacteria
– Improves activity vs.
* Gram negative bacilli (E.coli, K. pneumoniae etc..)
* Staphylococcus aureus
* Beta-lactam producing anaerobes
* No antipseudomonal coverage
In a child with meningitis what level must the MIC be in order to use penicillin alone?
MIC <0.06
What is the mechanism for resistance in MRSA?
Altered penicillin binding sites
What is the drug of choice for ESBL?
Carbapenams +/- aminoglycosides
In a newborn with congenital CMV when would you treat?
<28 days old + moderate symptoms
Oral valganciclovir for 6 months
What are the clinical features of congenital rubella infection?
- SNHL (58% of patients)
- Eyes ‐ cataracts, retinopathy, micropthalmia (43% of patients)
- Cardiac – PA stenosis and PDA
+ neurodevelopmental disability
When do neonates receive varicella immunoglobulin?
- Neonatal exposure following maternal varicella
- > 7days before delivery – no treatment
- <7 before – 2(Aus) or 7 (NZ) days after delivery – VZIG
- All <28 weeks gestation – VZIG
What medication can be given to mothers positive for toxoplasmosis with unaffected foetus?
Spiramycin - doesn’t cross the placenta
Treatment for congenital toxoplasmosis??
Pyrimethamine
Sulfadiazine
Folinic acids
What is the treatment of neonatal syphilis?
IV Benzylpenicillin for 10 days
When could you get a false positive HIV test result?
Patient who has previous had CART therapy
How would you test for HIV in a child <18months old?
Viral PCR
Can’t do antibody testing as could be transferred maternal antibodies
What is the first line therapy for HIV?
2 NRTIs + third drug (NNRTI, INSTI or PI)
Which class of HIV treatment is a CYP3A4 inhibitor?
Protease inhibitors
When is window treatment given for TB?
Child <5 years old who has been exposed to a confirmed case of TB less than 10 weeks prior whilst awaiting TST/IGRA testing.
What is the main side effect of ethambutol that is monitored for?
Optic neuritis and red/green colour blindness
What antibiotic is used to treat stenotrophomonas maltophilia?
IV Co-trimoxazole (also used in PJP)
What are the features of Aspergillus on high resolution CT scan?
Halo sign
Air crescent sign
What is first line treatment for invasive Aspergillus?
Voriconazole
What treatment would you start in an immunosuppressed patient who you suspect has a fungal infection?
Liposomal Amphotericin (toxic to the kidneys)
What is first line treatment for candidaemia or invasive candidiasis?
Caspofungin (doesn’t have urine or CSF penetration)
What anti fungal is used for neonates?
Conventional amphotericin
Which one of the following confers the greatest risk for the development of fungal infection in a patient undergoing chemotherapy?
Prolonged severe neutropenia
Where is invasive Aspergillus mainly found?
Brain, chest, sinuses
What is used to treat haemorrhagic cystitis in BK infection?
Cidofovir
What are you at risk of if you are taking infliximab?
Reactivation of latent TB
Should have interferon gamma assay and CXR prior to commencing as it is an anti-TNF monoclonal antibody
Which vaccines should be avoided in babies within the first 12 months whose mothers have been on biological agents such as infliximab?
Live attenuated vaccines such as BCG
What are the high risk HPV serotypes?
HPV 16 and 18 (Cervical cancer)
Low risk 6 and 11 (cause of non-malignant genital warts and recurrent respiratory papillomatosis)
Which bacteria are catalase negative?
Streptococcus
Enterococcus
