Rational use of Antibiotics

1. Rational use of Antibiotics Dr Malika Karunaratne Consultant Microbiologist NIHS Kalutara

2. Introduction • Different from other drugs- • misuse can affect the response of future patients. • Irrational use – major problem-development of resistance • Few groups of antibiotics to attack large number of bacterial spp

3. Cost of antibiotics • Not just the unit cost of the antibiotic • Materials for administration of drug • Labourcosts • Cost of monitoring levels

4. What is Rational Use? • Is an antibiotic necessary? • All fevers are not due to infections • All infections are not due to bacteria • All bacterial infections does not need antibiotics- consider other options: surgery , antiseptics, self limiting • There is no evidence that antibiotics will prevent secondary bacterial infection in patients with viral infection

5. What is Rational Use? • Correct antibiotic / choice of antibiotic • Start at the correct time • Correct dosage and correct route • Correct duration

6. Correct antibioticfor empiric therapy • Community acquried infection- • Eg-pneumonia. UTI, skin infections • usually from pathogens sensitive even to narrow spectrum antibiotics • Hospital acquired infections – • Eg- SSI, VAP, HCA UTI , etc • pathogens are multi drug resistant- broad spectrum antibiotic as the first line therapy

7. Correct antibiotic? For empiric therapy • causative agents /most likely pathogen depends on the site of infection • Skin infections –Staph,Strep, rarely Coliforms/Pseudo - Surgical prophylaxis – Mainly to cover skin carriers • known colonizer (MRSA/ESBL?)

8. No anarobic activity – aminoglycoside/quinalones/cephalosporins • No Gram negative cover – clox/glycopeptides/clindamycin • No gram positive cover – aztreonam /ceftazidime • Less anti staph cover - CTX/CRO • Ciprofloxacin-no Pneumococcal cover • Nalidixic acid- no Staphylococcaal cover

9. Correct antibiotic? cont • Adequet concentration at the site • concentrated well in bones-ciprofloxacin/fusidic acid • Prostate – quinalones • Penetrate into deep abscesses clindamycin • 1st and 2nd gen cephalosporins, aminoglycosides- no CSF penetration

10. Correct antibiotic • Severity of the infection • Host factors and side effects– age, renal and hepatic involvt, pregnancy allergies ect • Antibiotic sensitivity patter of the likely pathogen - before ABST results local sensitivity data vary from country to country ,hospital to hospital and from unit to unit

11. Best guess principle for correct antibiotic • Predicting the most likely pathogen • Most likely site • The antibiotic sensitivity pattern CA/HA • local susceptibility patterns of micro organisms- • Severity of the patients illness • patient factors • Current national and local guidelines – BNF recommendations local guidelines

12. Correct antibiotic? Specific therapy • Interpretation of the ABST report- • what is isolated is not necessarily the pathogen. • It could be a contaminent or colonizer • Was the specimen properly collected?/ proper container? • sensitivity reports are at best a guide

13. Correct time • As soon as diagnosis of infection made and (appropriate sp have been collected) • Surgical prophylaxis – One hour prior to skin incision do you continue this until drain tubes are removed?

14. Correct dosage • BW • Ability of the drug to penetrate into site of infection Higher doses/prolonged therapy poor drug penetration to the site, difficult to eradicate infections eg- Endocarditissepticaemia, meningitis , brain abscess • Impairment of excretion – dose adjustments

15. Correct route • Severe infections – IV therapy • Endocarditissepticaemia, meningitis – always parenteral • Topical antibiotics-use only in clearly defined clinical situations - Eg- ENT and opthalmic infections absorb in sub theraputic dosages- promote resistance development

16. Correct duration • Duration varies. • usually 7 to 10 to 14 days (Severity of the infection , Clinical and Biochemical response) • deep seated, difficult to eradicate from the site longer duration- 4-6 weeks • Removal of pus – shorter duration

17. Correct duration Duration varies. • All prescriptions must be reviewed after 5 days of rx. • In severe infections prescriptions MUST BE REVIEWED in 24- 48 H to assess the clinical response

18. All IV prescriptions MUST BE REVIEWED after THREE DAYS • IV antibiotics can be switched to oral equivalents after 48 - 72 hrs if, • temp <38 at least for 24 hrs • clinical improvement observed • WBC and CRP improving • haemodynamically stable • oral route viable • UNLESS AN EXTENDED IV DURATION IS SPECIFICALLY STATED. (Meningitis, Endocarditis, Osteomyelitis, Septic arthritis, Discitis, Bacteraemia (positive BC), Necrotizing fasciitis)

19. Combination therapy increase the spectrum of antibacterial activity - • Empirical therapy – causative organism is not known • Prevention of drug resistance eg – anti TB therapy fusidic acid alone • Polymicrobial infections intra abdominal and pelvic infections,braain abscess • immunocompromised pt • Synergistic effect – endocarditis • To allow dose of a toxic agent to be reduced • Not properly combined- antagonism

20. Clinical problems • 5 year old boy • Came to OPD with his mother • Fever, running nose, cough for 2 days • O/E • Fever 101 F • Lungs – clear Probable diagnosis? What is your management?

21. Probable diagnosis –Acute bronchitis/ commonly Viral in origin • What is your management? • Symptomatic treatment • No antibiotics All infections are not due to bacteria • Do you give antibiotics to prevent secondary bacterial infections? There is no evidence that antibiotics will prevent secondary bacterial infection in patients with viral infection

22. Meta-analysis of 9 randomised placebo controlled trials involving 2249 patients Conclusions: There is not enough evidence of important benefits from the treatment of upper respiratory tract infections with antibiotics and there is a significant increase in adverse effects associated with antibiotic use. Arroll and Kenealy, Antibiotics for the common cold. Cochrane Database of Systematic Reviews. Issue 4, 2003

23. 69 year old female • Presented to OPD • Fever 5 days • Cough with yellow sputum • crepitations++ • No recent exposure to antibiotics/no co morbidities • What is your management • CXR--- no consolidation • (WBC/DC – 15,000 mg/dl , neutrophil 80%) • Amoxycillin 500mg 8hrly / • Cefuroxime 500mg 12hrly oral 5-7 days/ • R/V in3days or before

24. If above patient is presented with dyspnoea • CXR – Shadow at the R lung base • CURB 65 is 2 – moderate CAP • What will you do? • admit- IV therapy is indicated. • Ix- blood culture/sputum culture/CRP • If CURB 65 is 3 – severe CAP- patient needs urgent admission and IV antibiotics

25. Common organisms for CA P • Strep.pneumoniae • Heamophilusinfluenzae • Mycoplasmapneumoniae • Cefotaxime 1g 8hrly/ Ceftrioxone 1g daily/ Co-amoxyclav 1.2g 8 hrly • + Clarythromycin 500mg 12 hrly • Consider PO step‐down after 48 hours if patient improving

26. If CURB 65 is 4 or more –ICU • Severe CAP in ICU- inaddition, consider antipseudomonal cover • Levofloxacin is an option for high severity pneumonia not responding to Co-amoxiclav/clarythro combination

27. ACUTE EXACERBATION OF COPD (No consolidation on Chest X‐ray ,no history of antibiotic exposure with in last 3 months) Only give antibiotics if 2 or more of the following are present • • ↑ breathlessness •↑ sputum volume •↑ purulent sputum • Amoxicillin 500mg TDS PO for 7 days OR Co-amoxiclav 625mg tds or Clarithromycin500mg BD PO for 7 days

28. SINUSITIS • Acute – most cases are viral, treat with analgesics/anti‐inflammatories /steam for 3 days • Thereafter treat as chronic • Chronic 1st line: Co‐amoxiclav 625mg TDS PO for 5 days

29. BACTERIAL TONSILLITIS Do you treat? Do you use co-amoxiclav? • 1st line: Penicillin V 500mg QDS PO for 10 days • 2nd line (Penicillin allergy): Clarithromycin 500mg BD PO for 10 days

30. BONE AND JOINT INFECTIONS Unless the patient has clinical features suggesting ‘sepsis’ relating to their bone or joint infection it is better to delay antibiotic therapy until appropriate sampling has been undertaken

31. 70 years old patient with chronic wound • no fever • no redness/unusual swelling/surrounding cellulitis • DIAGNOSIS- DIABETIC FOOT ULCER Do you treat him with antibiotics? • Do not treat with antibiotics unless evidence of infection • Always seek specialist advice

32. BITES • Is an antibiotic necessary? • YES • Prophylactic co amoxiclav

33. 30 year old woman • 2 days dysuria, increased frequency • No fever • No recent history of UTI • Uncomplicated UTI(non pregnant female with no anatomical or functional defect) • Organisms • E.Coli • Staph. Saphrophyticus • Urine culture – not essential, if facilities are there test can be performed • Nitrofurantion • Nalidixic acid-? • Coamoxyclav • Cephalexin/ cefuroxime

34. 45years old patient came to OPD with watery stools 5-6 times /day for last 24 hours • fever + , No blood in stools • no evidence of dehydration What is your management? Salmonellosis- zoonotic, self limiting Shigellosis- if severe infection, blood and mucus

35. Antibiotics are indicated only for severe diarrheoa – watery stools more than 6 times per day, blood and mucus , extremes of age, immunocompromised

36. TAKE HOME MESSAGE • Antibiotic resistance is a major problem world-wide • Resistance is inevitable with use • No new class of antibiotic introduced over the last two decades • Appropriate use is the only way of prolonging the useful life of an antibiotic