Infectious diseases Flashcards
MRSA - gene causing resistance?
MecA gene
VRE - gene causing resistance
Van - multiple genes
VanB more common
ESBL - how is resistance transmitted
Plasmid mediated - multiple genes
Resistance to Pen and 3rd gen ceps,
Sensitive to 2nd gen/Carbapenems/beta lactamase inhibitors (tend to use carbapenems as other drugs not good in vivo activity)
ESCAPPM - how is resistance transmitted
Chromosomal mediated, inducible
AmpC gene leading to beta lactamase production
Rx Carbapenems
What genes confer resistance to carbapenems
Multiple genes found in enterobacteriaceae
KPC (Klebsiella Pneumonia Carbapenemase)
NDM (New Delhi Metallo beta lactamse 1) found in E.coli (and others). Rx Tigecycline, Colistin
Meningitis
ceftriaxone, aciclovir, pred
add ampicillin if immunosuppressed to cover listeria
IE
genta + benpen + fluclox
toxoplasma
HIV CD4+ < 100
multiple ring enhancing lesions
DDx: primary CNS lymphoma (single or multiple), PML (enhancing areas, CMV (non specific imaging), HIVE (diffuse change)
cellulitis
strep pyogenes, staph aureus
flucloxacillin
clindamycin if pen allergy / no response
COPD exacerbation
haemophilius influenzae
strep pneumoniae
moraxhella catarrhalis
if pneumonia - strep pneumo
meningitis
ceftriaxone - meningococcal cover
benzylpenicillin - listeria cover
vanc if hospital / surgery etc - MRSA cover
pen allergy: vanc + cipro / maxi
prophylaxis: ceftriaxone / cipro
pneumonia in etOH excess
klebsiella
colistin
GN cover only
malaria
artemether /lumefantrine - non severe artesunate - severe falciparum quinine - if pregnant mefloquine (larium) psych SEs atovaquone /proguanil (malarone)
cefepime
no useful activity against MRSA
MERS
middle eastern respiratory syndrome
9-12 day incubation
50% mortality
diagnosis from LRT PCR
PCP
Bactrim
2nd line: clindamycin + primaquine
add steroids if PaO2 < 70mmHg
Staph Aureus methicillin resistance
via production of penicillin binding protein PBP 2A
nitrofurantoin
SEs fever + hepatitis (self limiting)
GN UTI
DNA gyrase mutation
fluoroquinolone resistance
GN resistance
efflux pumps, porins
penicillin resistant staph aureus
penicillinase production
live vaccines
MMR, oral polio, varicella, yellow fever, BCG, japanese encephalitis, rotavirus, oral typhoid, smallpox
HIV + TB together
start HAART 8/52 post TB therapy if possible
culture negative meningitis
NSAIDs, cryptococcus, TB, sarcoid, behcets, malignancy
gentamicin
GN sepsis incl pseudomonas
beta lactams
bactericidal activity directed at cell wall
carbapenems, cephalosporins, penicillins
carbapenems
GN, pseudomonas, GP
inactive against: e faecium, MRSA, pseudomonas
inactivated by metallobeta lactamases
cephalexin, cephazolin
strep, staph, E coli, klebsiella
inactive: enterococci, listeria, pseudomonas
ceftriaxone
GN rods, staph; meningitis
inactive: enterococci, MRSA
resistance develops: serrate, citrobacter, enterobacter; ESBL - e coli, klebsiella, enterobacter
ceftazidime
enteric GN rods incl pseudomonas
inactive: ESBL enzymes
daptomycin
GPs only
not for lungs
AEs: myopathy
aztreonam
aerobic GNs incl haemophilus, pseudomonas
OK in penicillin allergy
bi/flucloxacillin
GPs incl staph with beta lactamase
cholestatic jaundice up to 6/52 post Rx
amoxy/ampicillin
drug of choice for enterococcus
beta lactamase
produced by staph, bactericides fragilis, h. influenza, e. coli, klebsiella
use augment / tazocin
tazocin / timentin
only penicillins for pseudomonas cover
some enterococci, klebsiella cover
fusidic acid
staph
never use alone (rapid resistance)
teicoplanin / vancomycin
GPs only
MRSA, MRSE
severe infx if penicillin allergy
vanc for metro resistant c diff
clinda / lincomycin
GPs
linezolid
GPs incl MRSA, coag neg staph, VRE, pen resistant strep pneumo only use in multi drug resistant infxs BM suppression; peripheral neuropathy serotonin syndrome
macrolides
azithro, clarithro, erythro, roxithro
GPs, legionella, corynebacteria, GN cocci, mycoplasma, chlamydia, anaerobes
erythro, clarithro - QT prolongation, inhibit 3A4
clarithro + colchicine = fatal BM toxicity
metronidazole
anaerobes
colistin
resistant GNs - pseudomonas
renal, neruotox
quinolones
cipro, moxi, norflox, oflox
rifampicin
MAC, TB, MRSA
AEs: thrombocytopaenia, AKI, flu like, orange body fluids
pristinamycin
GP, neisseria, mycoplasma, ureaplasma, chlamydia, haemophilus
Bactrim
PCP, MRSA, listeria, nocardia
tetracyclines
GP, GN
brain abscess
benpen + metro + cef
prostatitis
amoxy + gent
necrotising fasciitis
pen + gent + metro
CCR5
early coreceptor for HIV (macrophages)
delta32 mutation predicts indolent disease and relative resistance to infection
CXCR4
later coreceptor for HIV (T cell)
HLA B57 HIV
allergic to abacavir
better prognosis HIV
HIV + HCV
HAART first; HCV therapy once CD4 > 100
Causes of bloody diarrhoea
shigella, salmonella, campylobacter, E histolytica
varicella in pregnancy
infectious: 48 hours pre rash to vesicle crusting
incubation: 10-21 days
fatal threat: < 20/40; within 5/7 of delivery
VZIg within 72/24 of contact to lessen maternal illness
VZIg to baby if born within 5/7 of maternal infx or exposed in 1st week of life
HLA associations
HLA-A3 haemochromatosis HLA-B5 Behcet's disease HLA-B27 ankylosing spondylitis Reiter's syndrome acute anterior uveitis HLA-DQ2/DQ8 coeliac disease HLA-DR2 narcolepsy; Goodpasture's HLA-DR3 dermatitis herpetiformis Sjogren's syndrome, PBC HLA-DR4 type 1 diabetes mellitus* rheumatoid arthritis
