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Flashcards in Community acquired infections Deck (21):
1

What are the most common bacteria infections in meningitis for 3 month - 50 year olds?

What about 50+?

Neisseria meningitis
Streptococcus pneumoniae

Hib used to be a big deal, pre-vaccination era

In the over 50s, or those with immunosuppression, we worry about Listeria monocytogenes

2

which populations are more susceptible to pneumococcus?

young children
elderly
ATSI
asplenia
chronic disease

3

what are the serotypes of N. meningitidis?

what's in the vaccine?

a,b,c, y and W-135

the vaccine does not contain the B serotype, but a reverse engineered vaccine has recently become available

4

what are the contact treatments for meningococcus?

if pregnant?

if pregnant, CTX 250mg IM

cipro 500mg once
rifampicin

Penicillin will not eradicate carriage

5

what is the treatment for meningitis, when gram-positive cocci in pairs are seen on gram-stain of CSF?

are there any other times when meningitis treatment is changed?

in this setting it is recommended that we give CTX/cefotaxime PLUS vancomycin at high doses

CAN STILL USE PENICILLIN FOR CHEST INFECTIONS - CAN GET HIGH TISSUE LEVELS IN THAT SETTING

6

what are the new treatment guidelines for meningitis in Australia?

what about if pen allergic?

describe the different types of pen allergies

if there is a delayed penicillin reaction/rash ONLY

then we use CTX 2g BD

If immediate hypersens rxn (angioedema, urticaria, anaphylaxis, bronchospasm)
- vancomycin PLUS cipro
OR
single agent moxifloxacin (400mg IV)

7

how does listeria meningitis present?

what does the Gram stain look like?

treatment?

it is in the older, immunocompromised patients

there is rhombencephalitis with cranial nerve signs, ataxia can occur
hemiplegia can occur
seizures may be a finding

PARTICULARLY FOCAL FINDINGS

Gram stain is Gram pos rods

this bug is intrinsically resistant to cephalosporins, so use BenPen or Amp

8

what are the CSF findings of encephalitis?

elevated protein
LL predominance
usually normal glucose
85% have increased red cells

add aciclovir until HSV encephalitis is excluded!

9

what are the common causes of brain abscess in an immunocompetent person?

it is a polymicrobial infection

esp S. milleri and anaerobes

treatment is aspiration

ABx = CTX and metronidazole

10

what is the empirical treatment of an abscess less than 5cm when patient systemically well?

incision and drainage.

11

what are the two most common pathogens in skin/soft tissue infection?

strep pyogenes (Group A) - erbcellicent cellulitis

staph aureus in focus disease (like abscesses and furuncles

12

what is the distinction between multi-resistant MRSA and non-multiresistant MRSA?

mMRSA = resistant to fluclox PLUS three additional classes of antibiotic (e.g. gent, TMP/STX, lincomycin) - this used to be HA-MRSA

nmMRSA = resistant to fluclox, but susceptible to other classes - this used to be called CA-MRSA
- this usually requires trimethoprim-sulphamethoxazole or clindamycin for treatment

13

what is the Panton-Valentine-Leukocidin cytotoxin?

this is apparently a cytotoxin that increases virulence

it is classically associated with nmMRSA

seems to be associated to with outbreaks

14

what is the classical bug from a freshwater, waterborne skin infection?

Aeromonas hydrophilia
- Gram neg rod
- fresh water predeominance
- very rapid onset of disease
- Fluoroquinolones are the agent of choice

STRONGLY ASSOCIATED WITH TRAUMA

15

what is the super nasty bug that is associated with estuary habititats?

vibrio vulnificus
- gram neg
- classic "flesh eating" bug
- free living in the estuary and marine habitats

Almost always occurs in those with co-morbidities, esp liver diease/EtOH or HCM

fulminant infection with necrosis and septic shock

HIGH MORTALITY

treat with doxycycline

16

what is the cause of "fish tank cellulitis"?

associated with skin/soft tissue infection after cleaning out a fish tank!

Mycobacterium marinum
- acid fast bacillus

- diagnosis is of granulomas and culture of tissue sample

treatment is excision +/- clari+ethambutol

17

what are the common bugs in animal bites?

what is empirical treatment?

these are typically considered low risk wounds, unless the involve joints/tendons and do not need empirical ABs if debrided within 8 hours

they are often polymicrobial

involved organisms include:
- natural skin flora (staph, strep) plus the animal oral flora

dogs and cats:
1. most important is Pasteurella multocida
2. capnocytophagia canimorsus
3. anaerobes and microaerophilic Streptococic

Bartonella henselae is a RARE organism - results from cat scratches rather than bites

Treatment is:
washout/debridement
oral Aug DF
or IV Pip/taz
IV CTX/metro

18

what are the bugs in nec fasc?

there are two major variants:

1. monobacterial
- strep pyogenes
- staph aureus
- clostridium perfringens (gas gangrene)
- waterborne Gram-negs

2. polymicrobial/synergistic gangrene
- Fournier's gangrene
- diabetes or other immune compromise

19

what is the antimicrobial treatment of nec fasc?

broad spectrum to cover everything, AND MRSA AND add an anti-toxin

usually this would mean:
- carbapenem
- clindamycin for its anti-toxin effects against toxin-releasing bugs like strept and staph
- an agent with definite MRSA activity (vanco)

20

what is the most common cause of acute diarrhoea in Australia?

rotavirus, norovirus, adenovirus, astrovirus

it is managed with supportive care and close infection control

these are notifiable diseases and are particularly relevant in nursing homes/aged care facilities

21

A 22-year-old overseas student working on an Australian dairy farm develops rapid-onset fevers (39.8°C), headache and myalgias

Laboratory results show
-ALT 96, AST 76
- Platelets 138
- FBC normal
- Creatinine normal
- Nose and throat swab for respiratory virus RNA – negative
- Lumbar puncture – WBC 0, protein and glucose normal

What is the likely diagnosis?




this is concerning for Q fever

refer to the zoonotic infection lecture for details about treatment

presentation can be:

non-specific febrile illness, hepatitis, pneumonia, meningo-encephalitis