Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Infection & Immunity > Treating Infection > Flashcards

Treating Infection Flashcards

0
Q

Name some examples of specific and supportive treatment in cases of infection.

A

SPECIFIC:

  • antimicrobials
  • surgery (drainage e.g. of pus, debridement - removal of dead/damaged tissue - & dead space removal - preventing further infection)

SUPPORTIVE:

  • symptom relief
  • physiological restoration (combat changes caused by infection e.g. pH, O2, CO2)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
1
Q

List some of the different mechanisms of infection and give examples for each.

A

Contiguous/direct spread: one part of body to another
e.g. commensals in bowel causing UTI, perforation of organ causing peritonitis

Haematogenous: bloodstream spread e.g. endocarditis

Ingestion: faecal-oral e.g. Salmonella enteritis

Inoculation: contaminated object entering body e.g. bite (Rabies), stabbing

Inhalation: droplet/aerosol

Vector: third party organism e.g. mosquito, ticks

Vertical: intrauterine e.g. syphilis, toxoplasmosis; during delivery e.g. HIV, hepatitis B

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are some important things to consider when using antimicrobials?

A

Bacteriocidal (kills bacteria) v.s. bacteriostatic (prevents multiplication of bacteria)

Broad v.s. narrow spectrum

  • selectively toxic
  • few side-effects
  • reach site of infection
  • oral/IV
  • long half-life (infrequent dosing)
  • no interference with other drugs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Give some examples of antibacterial drugs which target cell wall synthesis.

A

Beta-lactams =

  • Penicillins: penicillin (Streptococci), amoxicillin (Streptococci & some Gram+ve), flucloxacillin (Staph. & Strep.), co-amoxiclav (all above + anaerobes + lots of Gram-ve)
  • Cephalosporins: cetriaxone (acts in CSF: blind treatment of meningitis)
  • Meropenem: broad spectrum, almost all Gram-ve, generally safe for penicillin allergy

Glycopeptides (vancomycin) = most Gram+ve, some enterococci resistant VREs, Staph. resistance rare, not absorbed, narrow therapeutic window

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Give some examples of antibacterial drugs which target protein synthesis.

A

Tetracyclines (doxycycline): oral, broad spectrum, specifically used in penicillin allergy, Gram+ve, atypical pneumonia, chlamydia, some protozoa inc. malaria treatment & prophylaxis, DON’T GIVE TO <12yrs)

Aminoglycosides (gentamicin): Gram-ve, severe Gram-ve sepsis, blood/urine, potentially nephro/ototoxic, narrow therapeutic window

Macrolides (erythromycin): intracellular penetration, alternative to penicillin for mild Gram+ve, atypical respiratory pathogens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Give some examples of antibacterial drugs which target nucleic acid synthesis.

A

Quinolones (ciprofloxacin): inhibit DNA gyrase, lots of activity on Gram-ve, atypical pathogens, increased chance of resistance & risk of Clostridium difficile

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Give some examples folic acid synthesis inhibitors.

A

Trimethoprim

Sulfonamides

e.g. co-trimoxazole for pneumocystis pneumonia & MRSA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Give an example of an anti-fungals.

A

Fluconazole for Candida albicans

inhibits cell membrane synthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Give some examples of antivirals.

A

Aciclovir: Varicella zoster, Herpes simplex
(inhibits DNA pol)

Tamiflu: flu A & B

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is metronidazole used to treat?

A

Anaerobic bacteria & protozoa (amoebae, diarrhoea, vaginitis)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How would you measure antibiotic activity?

A

Disc sensitivity testing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How would you determine the minimum concentration of an antibiotic required to inhibit bacterial growth?

A

Minimum inhibitory concentration:

Double dilution of antibiotic-bacterial solution until bacteria is visible

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the types of horizontal gene transfer?

A

Conjugation = temporary union of unicellular organisms to exchange genomic material

Transduction = transfer of genetic material between bacteria via a bacteriophage or plasmid

Transformation = uptake of fragments of genetic material by bacteria which are then incorporated into the recipient genome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Give some examples of mechanisms of antibiotic resistance.

A

Drug inactivating enzymes e.g. beta-lactamases, aminoglycoside enzymes

Altered target (reduces affinity for antibiotic) e.g. meticillin, macrolides, trimethoprim

Altered uptake: reduced permeability (beta-lactams)/increased efflux (tetracyclines)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Outline the transmission, signs and symptoms, and treatment of cellulitis.

A

Severe inflammation of dermal and subcutaneous layers of the skin

note: the term erysipelas also used (superficial form of cellulitis)

Direct contact (break in skin)
e.g. cuts, bites, surgery, psoriasis, Athlete's foot, etc.

Most common causative organisms = group A beta-haemolytic Strep. (e.g. S. pyogenes) & Staph. aureus

S&S:

  • inflammation: rubor (erythema), tumor, dolor (tender to touch)
  • +/-fever
  • throbbing area of inflammation which spreads
  • “unwell”
  • tends start on the leg and move up

Treatment:

  • start antibiotics immediately - flucloxacillin 1st line
  • check spread of infection by marking edge of inflammation
  • examine heart in case it has spread —> endocarditis
  • RICE = rest, ice, compression, elevate

note: necrotising fasciitis mimics cellulitis in the early stages (but has severe, constant pain out of proportion to physical signs)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Outline the transmission, signs and symptoms, and treatment of conjunctivitis.

A

Inflammation of conjunctiva of eye (mucous membrane lining the eyelids and sclerae)

Direct contact e.g. touching eye, makeup application, eye drops

Causative organism usually viral (e.g. adenovirus) but can also be bacterial (e.g. Staph. aureus, N. gonorrhoe, Chlamydia) or can be due to allergy rather than infection

S&S:

  • soreness
  • redness
  • discharge
  • burning
    etc.

Treatment:

  • analgesia
  • hydration
  • medication depends on cause
16
Q

Outline the structure, replication, transmission, diagnosis, clinical presentation, and treatment of Streptococcus pneumoniae infection.

A

STRUCTURE = Gram+ve diplococci, anaerobic, alpha-haemolytic

TRANSMISSION = aerosol

COMMENSAL = found in resp. tract & nasopharynx

DIAGNOSIS = Gram stain (presence of neutrophils also)
catalase -ve, green on blood agar (alpha-haemolytic)

CLINICAL PRESENTATION =

  • community acquired pneumonia
  • pneumococcal meningitis
  • sinusitis
  • otitis media

note: pneumococcal disease usually affects >5yrs & 65yrs< or chronic heart, lung, liver disease + sickle-cell anaemia +HIV/AIDS

TREATMENT =

  • penicillin if sensitive
  • otherwise vancomycin or ceftriaxone
17
Q

How can Staphylococcus and Streptococcus be differentiated and identified?

A

Gram stain:

  • Staphylococcus = “bunch of grapes”, Gram+ve
  • Streptococcus = “string of pearls” e.g. Strep. pyogenes or diplococci e.g. Strep. pneumoniae, Gram+ve

Catalase:

  • Staphylococcus = catalase+ve
  • Streptococcus = catalase-ve

Staph. differentiation:

  • coagulase: only Staph. aureus is +ve
  • haemolysis: only Staph. aureus is haemolytic (beta - complete destruction of RBCs)

Strep. differentiation:

  • beta-haemolytic includes Group A (e.g. Strep. pyogenes), B, D (e.g. Strep. faecalis)
  • alpha-haemolytic (green on blood agar due to partial destruction of RBCs) e.g. Strep. pneumoniae
18
Q

Outline the structure, transmission, pathogenesis, diagnosis, clinical presentation, and treatment of Clostridium difficile infection.

A

STRUCTURE = Gram+ve rods, obligate anaerobes (but can form spores)

COMMENSAL = large intestine (becomes pathogenic after antibiotic treatment reduces commensal bacteria which compete with C. difficile and produce antimicrobials)

e.g. amoxicillin, cephalosporins, clindamycin, quinolones

PATHOGENESIS = endotoxins A & B
A —> produces enterotoxin —> damages membrane (so B can enter) & produces cytokines causing inflammation & excessive fluid secretion
B —> disrupts protein sysnthesis & produces cytokines causing inflammation

DIAGNOSIS = stool sample culture - Gram stain, ELISA (for toxins A & B)

CLINICAL PRESENTATION = pseudomembranous colitis

TREATMENT =

  • discontinue predisposing antibiotics, PPIs, immunosuppressants, laxatives, opioids (if possible)
  • fluid replacement
  • oral metronidazole (IV if more serious) + vancomycin for severe diarrhoea
  • isolate patient and inform infection control
19
Q

What diseases do Clostridium spp. cause?

A

C. botulinum = botulism

C. perfringens = gas gangrene/food poisoning

C. tetani = tetanus

C. difficile = pseudomembranous colitis

20
Q

Give some examples of microorganisms which cause diarrhoea.

A

Watery diarrhoea
e.g. Bacterial: E.coli (enterotoxigenic), Salmonella typhi, Vibrio cholerae (“rice water” stools)
Viral: Rotavirus, Norovirus,
Parasitic: Cryptosporidium parvum (+ microscopic cysts in stool), Giardia lamblia

Bloody diarrhoea (dysentery)
Bacterial: E.coli (enteroinvasive), Campylobacter spp., Shigella
Parasitic: Entaemoeba histolytica

21
Q

Outline the structure, transmission, diagnosis, pathogenicity, clinical presentation, and treatment of Legionnaire’s disease.

A

STRUCTURE = Gram-ve rod, aerobic (Legionella pneumophila)

TRANSMISSION = aerosol of water vapour (found within amoebae & protozoae in water and soil)

PATHOGENICITY = phagocytosed by macrophages but phagosome and lysosome do not fuse —> protected environment —> replicates

DIAGNOSIS = Gram stain/Gimenez stain, urinary & respiratory antigen test

CLINICAL PRESENTATION = acute atypical lobar pneumonia (after travel e.g. to Southern Europe)

TREATMENT = macrolides/fluoroquinolones

22
Q

Why can fungi not be treated with antibiotics?

A

Fungi are eukaryotic, not prokaryotic

Infection & Immunity (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions