Antibiotics & Emerging Resistance

Transcription

1 Antibiotics & Emerging Resistance Some points to consider : A. Overview WHO and World Economic Forum say emerging antibiotic resistance is one of the greatest challenges facing mankind, we know what causes resistance and what to do, but have trouble collectively doing it (political and behavioural) The total cumulative tonnage of antibiotics used in a community seems to be the biggest driving force of resistance overall. This is best estimated as the average defined daily dose (DDD) per head of population Horticulture and agriculture are the biggest users in many countries (including NZ, over 56 tons per year, 7 tons penicillin to dry off milking cows), however the most resistance of concern for humans is where antibiotics are used most ongoing, namely hospitals, rest homes (LTCFs) and GP practices NZ prescribers generally believe (and may well do) that they follow good evidence based antibiotic prescribing patterns. However the end result is our DDD is amongst the highest 6 of the most high use EU countries To achieve lower overall medical tonnage antibiotic use, we are likely going to have to move more away from proven evidence of what works, to the balance of what is definitely needed because a given infection of mild to even moderate severity will often resolve itself without antibiotics albeit in a longer timeframe and with appropriate management/monitoring for the future benefit of ANY antibiotic availability for serious infections of the patients we have not seen yet

2 All and every antibiotic use drives/selects for resistance of not only the microbes causing a specific infection (e.g. wound), but also the collateral damage of removing all susceptible relatively good and potential pathogens from our vast microbiome of bacteria (90 trillion per person). Only resistant organisms survive and multiply post any antibiotic use. These resistant organisms can and do readily swap their genetic secrets (resistant plasmids, etc) amongst themselves, other species and genera (including potential pathogens and commensals). The good news is for all those that are carriers only of MDROs (i.e. not, and/or no longer infected) 90% of these carriers will spontaneously lose their MDRO (MRSA, ESBL, VRE) within 1-12 months so long as this carrier does not use antibiotics within this timeframe to reselect for resistance again before spontaneous clearance. This happens because there is a metabolic cost to bacteria carrying resistant plasmids/genes, so they multiply more slowly than susceptible bacteria of the same species. This does not happen with parasites, once resistance has occurred in a parasite it lasts for decades (as the NZ veterinary industry has found, and scabies/malaria resistance). However despite this MDRO transient carriage only, in an individual, the community routine infection swab MRSA rate in Canty is 5%, and in AKL 12%. i.e. our combined average DDD per person of antibiotic use in the community (increasing at 6% per year) keeps increasing our now (transient to an individual) endemic MDRO community rates! In a regional South Island hospital January 2014 (unpublished so far, so not named) the first 100 adult admissions were screened for MDROs as an indicative sample of MDRO community endemicity (at least for that population sample) 6% were ESBL positive, one VRE positive. So important to think of ALL people (HCW and patients) as potential MDRO carriers, not just the relatively small number that we know are positive (unless an individual is known to have an MDRO that is more resistant than what is already endemic in that community. Understanding our microbiome is key, and how it is shared routinely amongst others (we are like flour bags shedding skin) and including faecal flora sharing (witness Norovirus outbreaks in an institution 30-50% clinical infection rates of patients/residents/staff even though they are taking extra precautions because there is a known outbreak faecal oral spread). Good hand hygiene, cough etiquette and environmental cleaning can only slow down but not stop sharing of our combined microbiome (including the MDRO s within). It is every use of antimicrobials that creates/breeds the MDROs in the first place, then we share them. This has special applications for any areas where people who have a higher incidence of antibiotic use and are together and/or share touch items (e.g. waiting rooms, childrens toys, healthcare workers in general). There is no such thing as we shall try an antibiotic and see if it works, at least it will not do any harm (other than wiping out that individuals susceptible microbiome with unknown consequences, plus adding to community resistance).

3 B. Some Specifics If we are going to substantially reduce our total antibiotic use to help preserve efficacy, we will have to change from what we are doing now. This will involve new guidelines, medical and public understanding (habits, education and realities of competitive business environment) i.e. a paradigm shift e.g. Uncomplicated UTI s o 10% of patients presenting to a GP practice are often quoted as being for a UTI. Some practices in Canty have said their rate is higher, others lower. Whatever, this is a significant antibiotic use o Prior to antibiotic availability, UTI was a self limiting infection 98% of the time (albeit over days). 2% of those infected went on to get the serious infection pyelonephritis however o So, should we treat all these self limiting infections for the sake of the 2% that need antibiotics? o Or only monitor carefully and treat those with? pyelonephritis symptoms with antibiotics??? This would be a major philosophical change to accept (medical & patient)?! o Some hopeful guidance/facilitation of such an approach is offered by a German pilot randomised controlled study which showed no superiority of ciprofloxacin over ibuprofen for symptomatic relief in 80 women with uncomplicated UTIs. Good monitoring to detect the development of pyelonephritis would be needed though. About a quarter to a third of patients in both arms of the study did need a change in treatment due to no improvement. Note (as did they) that ciprofloxacin is a 2 nd line antibiotic to compare against, to give a high threshold of comparison. The NHS uncomplicated UTI treatment protocols generally recommend paracetamol instead of ibuprofen for safety reasons as the symptomatic treatment approach of choice Symptomatic treatment (ibuprofen) or antibiotics (ciprofloxacin) for uncomplicated urinary tract infection? - Results of a randomized controlled pilot trial Jutta Bleidorn, Ildikó Gágyor, Michael M Kochen, Karl Wegscheider and EvaHummers- Pradier

4 UTI Symptom Course days 0-7 o Rest homes (LTCFs) have a very high antibiotic overuse record (worldwide) promoting resistances (shared with hospital transfers). Dipsticks are totally unreliable indicators of UTIs in over 65 year olds in an institution (because of 30-50% asymptomatic bacteriuria carriage rate), plus the other 50% without bacteria in the bladder have raised leucocytes so in many LTCF populations without UTI symptoms only 20% will be dipstick negative. Yet the relatively untrained, high turnover carer workforce are commonly given (positive) dipstick as the guide of when to send a urine to the lab regardless of any (subtle) GU symptoms or not, so the lab processes the urine believing they must have been symptomatic otherwise they should/would not have been sent so on the positive result received by the GP and LTCF the pressure is on to treat because the assumption is the lab thinks and has confirmed that they have a UTI by providing ID and antibiotic susceptibilities - incorrect, clinical decision only

5 Cutaneous Abscesses o Most clinicians lance the abscess,? irrigate and provide cover with antibiotics with/without a swab as standard treatment Note the attached article of a USA 2013 survey 15 ED s USA wide, 74% response rate, 350 replies, 54% Physicians, 78% replies from University Teaching Hospitals - of 324 Physicians only 15% covered with antibiotics, unless cellulitis,or immunocompromised and this in a litigious framework Cellulitis o When cellulits of the leg, note that tinea maceration between the toes is often (?83%) the entry point for the Staph or Strep that has multiplied in this moist environment where the skin has now lost its integrity. Note this is a higher risk factor than commonly associated diabetes Impetigo o In practice often waiting for the individual s own immune system to get on top of that particular strain of Staphylocccus aureus (when it is Staph). This can take weeks to months, and although there are regimens of treatment/decolonisation that may have some benefit, these are often shorter term benefits and the resolution would have come anyway. However clinical judgement required for when serious infection and intervention is appropriate. Dilute bleach bathing (1:1000 including for infected moist eczema) is commonly used with success also. Topical antibiotics are generally best avoided (resistance and sensitisation reasons) Respiratory o Big subject but significant progress has been made in antibiotic reductions when viruses or non microbial causes (e.g. allergic, bronchitis, sinusitis). One tip on a CDC wise antibiotic promotion was to encourage examiners of lower respiratory infections believed to be of non bacterial cause, to repeatedly say out loud for the patient to hear during the stethoscope examination no sign of any bacterial infection here, or here, or here.... Makes it easier not to prescribe an antibiotic because the patient is better convinced.

6

7

8 BPAC Five key points from this are: 1. The per capita level of antibiotic consumption within a country is a powerful driver of the emergence and proliferation of antibiotic resistant bacteria within that country. 2. Countries vary greatly in the level of antibiotic consumption and countries with high per capita levels of consumption have high levels of antibiotic resistance. 3. The per capita level of antibiotic consumption in New Zealand in recent years has been higher than that in most European countries. During 2010, only Greece, Belgium, France and Italy (countries widely considered to have profligate levels of antibiotic consumption) had higher levels of consumption than New Zealand. 4. Between 2005 and 2012 the average annual increase in total per capita antibiotic consumption in New Zealand has been greater than 6%. 5. Increased efforts to reduce antimicrobial consumption in New Zealand are required to slow the spread of antibiotic resistant microbes, and preserve the utility of antibiotics for future generations. Ref: Rising antimicrobial resistance: a strong reason to reduce excessive antimicrobial consumption in New Zealand Ben Harris Medical Liaison Infection Control Team Canterbury Southern Community Laboratories 18 Logistics Drive, Harewood PO Box , CHRISTCHURCH 8143, NZ DDI Ph