Module 1 revision of Bacteria, infections and antibiotics Flashcards
Staphylococcus aureus
Gram positive cocci - Wound infections, food poisoning
Beta haemolytic
One of major pathogens isolated from clinical samples
Often associated with wound infections
Also food poisoning especially from salted food stuff due to high salt tolerance
Only coagulase positive species in Staphylococcus genus
Staph saprophyticus
Urinary infections in female
non-haemolytic
Streptococcus pyogenes
Gram positive cocci - Nasopharyngeal infections, wound infections
Vibrio cholerae
Vibrio Gram negative curved rods - cholera
Neiserria meningitides
Gram negative cocci - Meningitis
Escherichia coli (E coli)
Gram negative bacilli
Escherichia coli (E coli) – food poisoning, diarrhoeal or haemorrhagic gastroenteritis, wound infections
Can be symbiotic
MRSA – Methicillin Resistant Staphylococcus Aureus
Identified through methicillin sensitivity tests
Trypanosoma has a characteristic immunity evasion mechanism, what is it?
Trypanosoma changes surface protein production avoiding detection by antibodies
Staph epidermidis
aka Coagulase Negative Staph (CoNS)
Skin commensals
One of two main causes of neonatal sepsis from indwelling line infections
Biofilm formation inpentrable to antimicrobial agents and immune cells
Beta haemolytic Strep Group A (Strep pyogenes)
Wound infections, bacteraemia, URTI and ‘Strept throat’ – pharyngitis, post streptococcal infection complications
benzylpenicillin
Benzylpenicillin Penicillin (beta-lactam)
Narrow-spectrum
Gram positive
Cell wall - Inhibits bacterial peptidoglycan transpeptidase – beta-lactam mimics peptide bond which breaks down the cell wall
Bactericidal
Good selective toxicity – inhibition of bacterial cell wall which is unique to prokaryotes
Used for:
Pneumonia
Cellulitis
Meningitis
Not suitable for penicillin allergies
Poor oral absorption, has to be IV or IM
“Strep. Pyogenes
Strep. Agalactiae
C. perfringens(Bacilli)”
“Hypersensitivity reaction
Hemolytic anaemia”
flucloxacillin
Penicillin (beta-lactam)
Narrow spectrum
Gram positive
Cell wall Inhibits bacterial cell wall synthesis Bactericidal
Good selective toxicity – inhibition of bacterial cell wall which is unique to prokaryotes
Used for: Impetigo
Cellulitis
Diabetic foot infection
Not suitable in penicillin allergies
Can cause false positive urinary glucose results
Can cause accumulation of sodium in renal failure patients
“Strep. Pyogenes
Strep. Agalactiae
C. perfringens(Bacilli)
E. faecalis
E. coli
PCNase-producing Staph. Aureus”
“Hypersensitivity reaction
Hemolytic anaemia”
amoxicillin
Penicillin (beta-lactam)
Broad-spectrum
Gram positive
Cell wall - Inhibits bacterial cell wall synthesis Bactericidal
Good selective toxicity – inhibition of bacterial cell wall which is unique to prokaryotes
Used for: Community-acquired pneumonia
Acute exacerbation of COPD
UTI
Not suitable in penicillin allergies
Common side effect of D&V
Increased risk of convulsions in renal impaired patients
“Strep. Pyogenes
Strep. Agalactiae
C. perfringens(Bacilli)
E. faecalis
E. coli”
“Hypersensitivity reaction
Hemolytic anaemia”
co-amoxiclav
Penicillin (beta-lactam – amoxicillin and beta-lactamase inhibitor – clavulanic acid)
Broad spectrum
Gram negative
Cell wall - Inhibits bacterial cell wall synthesis Bactericidal
Good selective toxicity – inhibition of bacterial cell wall which is unique to prokaryotes
Used for: Acute diverticulitis
Diabetic foot infection
Cellulitis
Amoxicillin interacts with Warfrin
Can be associated with jaundice
Not for penicillin allergies
It contains amoxicillin (an antibiotic from the penicillin group of medicines) mixed with clavulanic acid. The clavulanic acid stops bacteria from breaking down amoxicillin, allowing the antibiotic to work better.
“Strep. Pyogenes
Strep. Agalactiae
C. perfringens(Bacilli)
E. faecalis
E. coli”
“Hypersensitivity reaction
Hemolytic anaemia”
ceftriaxone
Cephalosporin (beta-lactam)
Broad-spectrum
Gram-negative
Cell wall - Inhibits bacterial cell wall synthesis – binds to penicillin binding proteins
Bactericidal
Targets cell wall which is unique to prokaryotes
Research shows can have nephrotoxicity due to effects on mitochondria of kidney
Used for:
Community-acquired pneumonia
Cellulitis
Diabetic foot infections
Not complete selective toxicity
Severe interaction with Warfrin
Can give false positive Coombs’ test
“S.aureus
S.epidermidis
E.coli
Klebsiella
Psuedomonas”
Hypersensitivity reaction
cefazidime
Cephalosporin (beta-lactam)
Broad-spectrum
Cell wall Inhibits bacterial cell wall synthesis – binds to penicillin binding proteins
Bactericidal
Targets cell wall which is unique to prokaryotes
Research shows can have nephrotoxicity due to effects on mitochondria of kidney
Used for: Meningitis
Hospital-acquired pneumonia
Complicated UTI
Not for known allergy to cephalosporins
Can cause thromocytosis
False positive Coombs’ test
S.aureus
S.epidermidis
E.coli
Klebsiella
Psuedomonas
Hypersensitivity reaction
erythromycin
Macrolides
Broad-spectrum
Protein synthesis inhibitor - Binds to 50S portion of ribosome, preventing movement of ribosome along mRNA
Mostly bacteriostatic
Good selective toxicity
Dec 2020 – increased risk of cardiotoxicity
Used for: Impetigo
Cellulitis
Community-acquired pneumonia
Not for patients with long QT (toxicity)
Can cause electrolyte disturbances
Can cause serious rashes
“Streptococcus
H. Influenza
Mycoplasma
Pneumonia”
Coumadin Interaction (cytochrome P450)
ciprofloxacin
Quinolones
Broad-spectrum
bactericidal
DNA inhibitor - Inhibit topoisomerases so prevent supercoiling and replication
Eye infection
Diabetic foot infection
UTIs
Risk with long QT syndrome
Risks in children
Avoid in pregnancy – arthropathy
“Strep. Pyogenes
Strep. Agalactiae
C. perfringens(Bacilli)
E. faecalis
E. coli
PCNase-producing Staph. Aureus”
“Hypersensitivity reaction
Hemolytic anaemia
Interstitial Nephritis”
doxycycline
Tetracyclines
Broad-spectrum
Bacteriostatic
protein synthesis inhibitor, binds 30S and prevents peptide bond formation - Protein synthesis inhibitor Interfere with attachment of tRNA to mRNA-ribosome complex
Used for: Hospital-acquired pneumonia
Cellulitis
Acute exacerbation of COPD
Higher toxicity – binds to calcium and causes staining on teeth
To be used only in children for severe/life-threatening conditions when no other alternatives
“Helicobacter pylori relapse
Acne
Rickettsia
Mycoplasma
Spirochetes (Lyme’s disease)”
trimethoprim
Sulfonamides
Broad-spectrum
Folate synthesis inhibitor - Prevents synthesis of folate into tetrahydrofolate by inhibiting dihydrofolate
Tetrahydrofolate needed for DNA synthesis
Bacteriostatic
Good selective toxicity
Used for: Respiratory-tract infections
Catheter-associated UTI
Lower UTI
Can be a predisposition to folate deficiency
Diarrhoea and vomiting side effects
Teratogenic risk in first trimester
“Thrombocytopenia
Avoid in 3rd trimester”
metronidazole
Nitroimidazole
Broad-spectrum
Affects DNA/RNA - Causes DNA fragmentation Bactericidal
Only anaerobic organisms have enzymes needed to reduce metronidazole to its active form,
Used for: Anaerobic infections
Diabetic foot infection
Cellulitis
Potentially mutagenic, carcinogenic, teratogenic
Many not for use in children
Avoid UV or sun exposure with topical use
Seizures
meropenem
Carbapenem (beta-lactam)
Broad spectrum
Cell wall - Inhibits bacterial cell wall synthesis – binds to penicillin binding proteins
Bactericidal
Good selective toxicity – inhibition of bacterial cell wall which is unique to prokaryotes
Used for: Meningitis
Endocarditis
Hospital-acquired scepticaemia
Common side effects of abdo pain, diarrhoea
False positive
IV only
Broadest of any antibiotic (except MRSA)
clarithromycin
Macrolides
Broad-spectrum
Protein synthesis inhibitor - Binds to 50S portion of ribosome, preventing movement of ribosome along mRNA
Most bacteriostatic
Good selective toxicity
Used for:Cellulitis
Impetigo
Community-acquired pneumonia
Electrolyte disturbances
IV not for children under 12
Safety in pregnancy not determined
“Streptococcus
H. Influenza
Mycoplasma
Pneumonia”
gentamicin
Aminoglycoside
Broad-spectrum
Protein synthesis inhibitor - Binds to 30S portion of ribosome and changes shape of it – causes mRNA to be read incorrectly
Bactericidal
Nephrotoxicity and ototoxicity (hearing or balance problems)
Used for: Eye infections
Diabetic foot infection
Meningitis
No oral form (IV or eye drops)
Increased risk of deafness in patients with mitochondrial mutations
“Aerobic Gram-
Enterobacteriaceae
Pseudomonas”
