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Antibiotics. James Clayton Consultant Microbiologist. Antibiotic groups. β-Lactams Penicillins Penicillin, Amoxicillin, Flucloxacillin PO/IV Penicillins + β-lactamase inhibitor Co-amoxiclav (Amoxicillin + clavulanate) PO/IV Tazocin (Piperacillin + tazobactam) IV
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Antibiotics James Clayton Consultant Microbiologist
Antibiotic groups • β-Lactams • Penicillins • Penicillin, Amoxicillin, Flucloxacillin PO/IV • Penicillins + β-lactamase inhibitor • Co-amoxiclav (Amoxicillin + clavulanate) PO/IV • Tazocin (Piperacillin + tazobactam) IV • Cephalosporins PO/IV • Carbapenems • Meropenem, Ertapenem IV
Other antibiotics: • Aminoglycosides • Gentamicin, (Amikacin) IV • Macrolides • Erythromycin, Clarithromycin PO/IV • Glycopeptides • Vancomycin, (Teicoplanin) IV • Tetracyclines • Doxycycline PO • Others • Trimethoprim, Nitrofurantoin PO • Rifampicin, Clindamycin PO/IV • Ciprofloxacin PO
Streptococci • Group A streptococci • Skin & soft tissue infection • Necrotising fasciitis • Tonsillitis • Toxic shock, sepsis • Group B streptococci • Neonatal infection, UTI • Other streptococci • Endocarditis, abscess
Streptococci & Enterococci • Strep. pneumoniae • URTI, pneumonia • Enterococcus faecalis / E.faecium • UTI, endocarditis
Staphylococcus • Staph. aureus • Skin & soft tissue infection • Abscess • Bone & joint infection • Line infections • Severe pneumonia • Remember MRSA • (Meticillin resistant S.aureus)
E.coli & coliforms • E.coli, Klebsiella, Proteus • UTIs • Intra-abdominal infection • E.g. cholangitis, sepsis • Hospital-acquired infection • Remember ESBLs
Neisseria & Haemophilus • N. meningitidis • Meningitis • N. gonorrhoeae • Gonorrhoea • H. influenzae • Respiratory tract infection • Meningitis (rare)
Pseudomonas • P. aeruginosa • UTIs (usually complicated / catheter) • Hospital acquired infections Anaerobes • Intra-abdominal infections • Skin & soft tissue infections • Abscess
Case 1 • John, 18 yrs old • Sore throat for 2 days, feverish • Exudate on tonsils when examined by GP • Tonsillitis diagnosed. • What organisms cause tonsillitis? • What antibiotics are appropriate?
Tonsillitis • Majority caused by Group A streptococci • Group A streptococci • Penicillin susceptibility ~ 100% • Erythromycin susceptibility ~ 80% • Penicillin preferred to Amoxicillin as: • Narrower spectrum • EBV / glandular fever reaction • Oral antibiotics in a community setting
Case 2 • Bob, 70 years old • COPD. 60 pack year smoking history. • Retired engineer. • 3 day history of cough, green sputum, malaise, raised temperature • o/e crepitations, reduced air entry • CXR – extensive consolidation • CURB-65 = 2 • No allergies
Community acquired pneumonia • Strep. pneumoniae ~ 30 - 40% • Haemophilus influenzae ~ 5 - 10% • Staph. aureus ~ 0.5 - 5% • Severity of infection (CURB-65 score) • Determines need for IV or oral treatment • Determines need for broad vs narrow cover
Don’t forget atypicals in CAP! • Legionella pneumophila ~ 1 - 5% • Mycoplasma pneumoniae ~ 1 - 10% • Chlamydophila pneumoniae < 10% ? • Chlamydia psittaci, Coxiella < 2% • Viruses including Influenza< 15% • Addition of • Macrolide e.g. erythromycin or clarithromycin • Tetracycline e.g. doxycycline • (Ciprofloxacin)
Case 3 • Katie, 25 years old • Presents to A&E with history of dysuria, frequency • Previously well
Do all antibiotics get into urine? These do: These don’t: Penicillins (few) Flucloxacillin (poorly only) Macrolides Erythro & Clarithromycin Tetracyclines Doxycycline Clindamycin • Penicillins (most) • Amoxicillin, co-amoxiclav • Cephalosporins • Carbapenems • Gentamicin • Trimethoprim • Nitrofurantoin • Ciprofloxacin • Vancomycin
UTI • Usually Gram-negatives as a cause • E.coli • Other coliforms (proteus, klebsiella) • Less commonly enterococci, staphylococci • Pseudomonas • Mainly in catheterised patients or those with underlying urinary tract disorders
Case 4 • Stephen, 17 years old • Admitted through A&E • Lethargic, drowsy, unwell • High fever • Photophobia & stiff neck • No allergies
Meningitis • Neisseria menigitidis (meningococcus) • Strep. pneumoniae (pneumococcus) • Haemophilus influenzae (HiB) • Listeria (extremes of age, immunocompromise) • Need IV therapy • Need antibiotics with good meningeal penetration
Case 5 • Albert, 82 years old • Had total hip replacement 5 days ago • On review today, unwell, coughing mucky sputum • Poor Oxygen sats, febrile • WCC 18, CRP 280 • CXR – widespread opacity • No allergies, no previous microbiology samples
Case 6 • Ivy, 82 year old • #neck of femur • Had a DHS 3 days ago. • Now has some erythema around the wound • Tender and wound feels hot. Well otherwise • Determined to be non-severe wound infection • Recent MRSA screen negative • Penicillin allergic (previous rash)