1. Antibiotic prescribing : Why is it an issue?
Ian Battersby
BVSC DSAM DipECVIM FRCVS

2. Antibiotic History

3. No new class of antibiotics since 1980s
How have we been using a commonly prescribed drug?
Unlike other drugs the more we use them their efficacy wanes….

4. Complex Issue Human Veterinary – Different species Mass prophylaxis
Welfare
Environment
Different countries : legislation e.g. Scandinavia
Different opinions !
Common thought – we recognise action is needed

5. MDR Bacteria Who are the main players?
Variety of Gram negative and Gram positive
‘ESKAPE’ pathogens
Enterococcus faecium
Staphylococcus aureus
Klebsiella pneumonia
Acinetobacter baumannii
Pseudomonas aeruginosa
Enterobacter species

6. How do Antibiotics influence Resistance Development…..

8. X

12. Bacterial Hyper-Mutational State
The simpsons
Antimicrobial level not high enough to inhibit/kill bacteria
Mechanisms to repair DNA replication errors in bacteria are inhibited

17. Too often
Too Long
Poor Dosing
Sub Therapeutic Levels

18. Practice Infection Control Policy
Hygiene/barrier
nursing protocols
Hygiene/barrier
nursing protocols
Antibiotics Prescribing Policy
(or stewardship)
Monitoring
Monitoring
How effective can these policies be…

19. J Small Ani Pract. June 2011;52(6):310-8.
Therapeutic antibiotic use patterns in dogs: observations from a veterinary teaching hospital.
J Small Ani Pract. June 2011;52(6):310-8.
OBJECTIVES: To describe therapeutic antibiotic use patterns in dogs at a small animal teaching hospital.
METHODS: A retrospective case analysis of randomly sampled antibiotic prescriptions in dogs from May 20th 2008 to May 20th 2009
RESULTS:
17% of therapeutic antibiotic prescriptions there was confirmed infection,
45% suspected infection
38% there was no documented evidence of infection.

22. Changing our prescribing habits

23. Changing Habits is Hard
The challenge
“ prescribe antibiotics just in case” vs. “ prescribe as they are indicated”
Changing Habits is Hard
Forming habits from N = 1

24. Were Abi prescribed ?

25. Were Abi prescribed ? Puppy Not vaccinated
Vomiting and Haemorrhagic diarrhoea
Pyrexic
Hypovolaemic, tachycardic

26. Were Abi prescribed ? Relatively Bright , Hydration Good
2 episodes of diarrhoea in 12 hours
Likes to scavenge!
Eating and drinking
Examination NAD

27. Were Abi prescribed ? 24 hours Anorexic Lethargic Diarrhoea 3x hr
Borborygmi
Vomiting
Is drinking

28. Were Abi prescribed ? 24 hours Anorexic Lethargic Diarrhoea 3x hr
Borborygmi
Vomiting
Is drinking

29. Human Acute Diarrhoea Guidelines

30. Consider the specificity of your findings for bacterial infection…
Antimicrobials
No Antimicrobials
Fever
Bacterial
Infection
viral,
protozoal,
Fungal
Sterile inflammatory disease
Immune mediated disease
Para-neoplastic
Metaphyseal osteopathy
Stress
Other example neutrophilia or protein in the urine

31. Is there a bacteria infection involved??
Cytology
Culture
Procalcitonin in humans
- pneumonia and sepsis

32. “Antibiotics are not a substitute for poor asepsis”
Surgical prophylaxis.
“Antibiotics are not a substitute
for poor asepsis”

34. In vitro resistance vs. Clinical ( in vivo) resistance

35. Clinical Resistance/Failure
Bacteria factors
Host factors
Pharmaco
dynamics
of the drug
WBC, cytokine,
Ab, Comp
In vitro
sensitivity*
Virulence
factors
Blood supply,
necrosis, drainage
Individual drug
properties
* MIC limitations
Rex and Pfaller (2002) – The 90:60 rule

36. Clinical Resistance/Failure
Bacteria factors
Host factors
Pharmaco
dynamics
of the drug
WBC, cytokine,
Ab, Comp
In vitro
sensitivity*
Virulence
factors
Blood supply,
necrosis, drainage
Individual drug
properties
* MIC limitations
Rex and Pfaller (2002) – The 90:60 rule

37. Siberian Husky – Anal abscess

38. ANTIBIOTIC PSEUDOMONAS E.COLI ENTEROCOCCUS
Amoxycillin RESISTANT RESISTANT RESISTANT
Amoxycillin-Clav RESISTANT RESISTANT RESISTANT
Cephalexin RESISTANT RESISTANT RESISTANT
TMS RESISTANT Sensitive RESISTANT
Gentamicin Sensitive * Sensitive * Sensitive *
Marbofloxacin Sensitive Sensitive RESISTANT
Erythromycin RESISTANT RESISTANT RESISTANT
Fusidic acid RESISTANT RESISTANT RESISTANT
Clindamycin RESISTANT RESISTANT RESISTANT

39. Clinical Resistance/Failure
Bacteria factors
Host factors
Pharmaco
dynamics
of the drug
WBC, cytokine,
Ab, Comp
In vitro
sensitivity*
Virulence
factors
Blood supply,
necrosis, drainage
Individual drug
properties
* MIC limitations

40. We want to Treat Effectively but not too long
How long…………………..?

41. Duration of Course Humans – Cochrane Reveiw Uncomplicated UTI –
young women 3 days vs 5-10 day
older women 3-6 d vs. 7-14
Pyelonephritis (non hospitalised)
7-14d vs d

42. Spectrum of Activity – Practice policy
Hard to do…. MTZ , aminoglycosides
Avoid combinations therapy
Avoid using certain antibiotics as first line agents
There are very strong arguments that antibacterials with restricted use in human medicine (e.g. imipenem, linezolid, teicoplanin, vancomycin) should not beused in animals

43. Thank you for listening 