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Dentistry and the antimicrobial resistance battle

1 April 2016

Dentistry and the antimicrobial resistance battle

Are we really approaching a post-antibiotic era? How did we get to this point and what can dentists do to help? Alice Bowe investigates...

 

Antimicrobial resistance (AMR) continues to pose a major public health threat worldwide. The overuse and misuse of antimicrobials has contributed to a rise in microbes that can no longer be treated by many current medicines[1].

Resistance is increasing to all microbials, including antivirals and antifungals, however the rate at which antibacterial resistance is evolving is a particular concern. In many countries, antibiotic resistance rates have more than doubled in the past 5 years[2]. The rapid spread of multi-drug resistant bacteria means that both common and life-threatening infections could soon become untreatable and many surgical and medical interventions made impossible. It has been estimated that 25,000 people die each year in Europe as a result of infections from antibiotic-resistant bacteria[3], with this number set to increase if trends continue.

In 2013, the UK government published a five year strategy to slow the development and spread of AMR[4]. Their aims include improving knowledge of AMR, conserving the effectiveness of existing treatments and encouraging development of new antibiotics.

Primary care dentists in the UK are responsible for prescribing up to 10% of all common antibiotics[5]. Studies have shown that many of these prescriptions could be unnecessary[6] and could be contributing to the rise in antibiotic resistance. By reducing antibiotic prescriptions it is possible that dentists could contribute to conserving the effectiveness of existing drugs and prevent further resistance.

The rise of resistance

Drug resistance is not a new concept. In his 1945 Nobel lecture, following the discovery of the first antibiotic, penicillin, Alexander Fleming warned that: “there is the danger that the ignorant man may easily underdose himself and by exposing his microbes to non-lethal quantities of the drug make them resistant.”[7] His fears materialised just four years after mass treatment with the drug when penicillin-resistant bacteria strains became prevalent. Its mass use introduced a major selection pressure for penicillin-resistant genes found in natural bacterial populations[8]. Since then, resistance to all types of antibiotics has emerged. Increasingly, the resistant genes have been found in a region of the bacterial DNA called the plasmid, which allows for rapid transfer of the genes between bacterial species. In some cases, bacteria have acquired multiple genes that make them resistant to a wide range of antibiotics, creating a ‘superbug’.

In high-income countries, extensive use of antibiotics in hospitals, the community and agriculture have all contributed to the selection and dominance of resistant strains within the community. In low and middle-income countries, where antibiotic use is increasing, high rates of hospitalisation and hospital infections are facilitating the spread of resistant strains. The increase of global travel and trade means that these resistant strains can now spread throughout the world quicker than ever[9].  

Dental prescribing

Since the discovery of penicillin, antibiotics have been used extensively in dentistry for both therapeutic and prophylactic purposes.  Penicillins are the most commonly prescribed antibiotics by dentists, with amoxicillin being prescribed the most[10]. However, a number of studies have highlighted the inappropriate use of antibiotics in dentistry, which could be contributing to antibiotic resistance[11],[12].

Therapeutic antibiotic prescribing: recommendations

Clinical situations that require antibiotic therapy are limited; the Faculty of General Dental Practice UK (FGDP) state that antibiotics should only be prescribed in primary care[13]:

  • As an adjunct to the management of acute or chronic infection
  • For the definitive management of active infective disease, e.g. necrotising ulcerative gingivitis
  • Where definitive treatment has to be delayed due to referral to specialist services, e.g. an inability to establish drainage in an uncooperative patient who requires sedation or general anaesthesia.

With regard to periodontal diseases, the FDI World Dental Federation state that “conventional periodontal treatment alone is adequate to ameliorate or resolve the clinical condition in the vast majority of patients with periodontal diseases.” They state that in some cases adjunctive agents can be used systemically or locally to enhance the effect of conventional periodontal therapy. However, careful evaluation of the patient’s clinical condition is needed before administering these.

Despite such guidelines, there are still cases in the UK where dentists are prescribing therapeutic antibiotics for conditions they are not indicated for. These include irreversible pulpitis, acute apical periodontitis[14] and dry socket[15].

Prophylactic antibiotic prescribing: recommendations

Antimicrobial prophylaxis, or the prevention of infection by the administration of antimicrobial drugs, is a contentious topic in all surgical fields in all medical specialities[16].

According to the FGDP, the only situation where prophylaxis could be considered in healthy individuals is prior to placing implants. However, even in this case, they state that there is little good-quality evidence to support the prophylactic use of antibiotics. Conversely, one small meta-analysis study has shown that administering amoxicillin preoperatively significantly reduces implant failure[17] [18].

In the past, antibiotic prophylaxis has been indicated in the UK for patients at risk of infective endocarditis (IE) before receiving invasive dental procedures. This was to prevent bacteraemias and metastatic infections as a result of dental treatment. However, in 2008, the National Institute for Health and Care Excellence (NICE) published new guidance recommending that antibiotic prophylaxis in the UK should cease[19]. They confirmed that the severity and frequency of bacteraemias is no greater than that from normal chewing or tooth brushing. They also stated that the severity of adverse drug reactions caused by the treatment would outweigh the few cases in which IE could be prevented and would not be cost-effective.

Despite recent research which shows a significant increase in the incidence of IE since the 2008 recommendation[20], NICE have confirmed that they see no need to change the existing guidance and that the increase in IE incidence could be due to a number of factors. Due to lack of evidence regarding dental procedures and bacteraemias, antibiotic prophylaxis is also not recommended for patients with prosthetic joints.

Conclusion

Antimicrobial resistance is one of the biggest challenges we face in modern healthcare. If trends continue, common occurrences such as a child falling over, or a cut to the hand could lead to fatal infection.

Judicious use of antibiotics in healthcare is a vital step in slowing the development and spread of antibiotic resistance. Dentists are well placed to contribute to efforts to reduce antibiotic prescriptions and should remain aware of the latest prescribing recommendations.

The British Dental Association has encouraged all dentists to “do their bit” by taking the pledge to become an Antibiotic Guardian, which can be done here: www.antibioticguardian.com.  

To hear about the “use and abuse” of microbials in the management of periodontal disease, watch this webinar by Dr Mike Milward on Healthcare CPD, worth 1.5 hours of verifiable CPD: http://healthcarecpd.com/course/the-use-and-abuse-of-antimicrobials-in-the-management-of-periodontal-disease

 

[1] http://www.fda.gov/ForConsumers/ConsumerUpdates/ucm092810.htm

[2] Johnson, T. M., & Hawkes, J. (2014). Awareness of Antibiotic Prescribing and Resistance in Primary Dental Care. Primary dental journal3(4), 44-47.

[3] Johnson, T. M., & Hawkes, J. (2014). Awareness of Antibiotic Prescribing and Resistance in Primary Dental Care. Primary dental journal3(4), 44-47.

[4] UK Five Year Antimicrobial Resistance Strategy 2013 to 2018: https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/244058/20130902_UK_5_year_AMR_strategy.pdf

[5] https://www.bda.org/amr

[6] Johnson, T. M., & Hawkes, J. (2014). Awareness of Antibiotic Prescribing and Resistance in Primary Dental Care. Primary dental journal3(4), 44-47.

[7] http://www.nobelprize.org/nobel_prizes/medicine/laureates/1945/fleming-lecture.pdf

[8] Davies, J., & Davies, D. (2010). Origins and evolution of antibiotic resistance. Microbiology and Molecular Biology Reviews74(3), 417-433.

[9] Laxminarayan, R., Duse, A., Wattal, C., Zaidi, A. K., Wertheim, H. F., Sumpradit, N., ... & Greko, C. (2013). Antibiotic resistance—the need for global solutions. The Lancet infectious diseases13(12), 1057-1098.

[10] Dar-Odeh, N. S., Abu-Hammad, O. A., Al-Omiri, M. K., Khraisat, A. S., & Shehabi, A. A. (2010). Antibiotic prescribing practices by dentists: a review.Therapeutics and clinical risk management6, 301.

[11] Johnson, T. M., & Hawkes, J. (2014). Awareness of Antibiotic Prescribing and Resistance in Primary Dental Care. Primary dental journal3(4), 44-47.

[12] Dar-Odeh, N. S., Abu-Hammad, O. A., Al-Omiri, M. K., Khraisat, A. S., & Shehabi, A. A. (2010). Antibiotic prescribing practices by dentists: a review.Therapeutics and clinical risk management6, 301.

[13] http://www.fgdp.org.uk/publications/antimicrobial-prescribing-standards/prescribing-antimicrobials.ashx

[14] Johnson, T. M., & Hawkes, J. (2014). Awareness of Antibiotic Prescribing and Resistance in Primary Dental Care. Primary dental journal3(4), 44-47.

[15] Dar-Odeh, N. S., Abu-Hammad, O. A., Al-Omiri, M. K., Khraisat, A. S., & Shehabi, A. A. (2010). Antibiotic prescribing practices by dentists: a review.Therapeutics and clinical risk management6, 301.

[16] http://www.fgdp.org.uk/publications/antimicrobial-prescribing-standards/prophylactic-antimicrobials.ashx#16

[17] http://www.fgdp.org.uk/publications/antimicrobial-prescribing-standards/prophylactic-antimicrobials.ashx#10

[18] Esposito, M., Grusovin, M. G., Coulthard, P., Oliver, R., & Worthington, H. V. (2007). The efficacy of antibiotic prophylaxis at placement of dental implants: a Cochrane systematic review of randomised controlled clinical trials. European journal of oral implantology1(2), 95-103.

[19] http://www.nice.org.uk/guidance/cg64

[20] Thornhill, M. H., Lockhart, P. B., Prendergast, B., Chambers, J. B., & Shanson, D. (2015). NICE and antibiotic prophylaxis to prevent endocarditis.British dental journal218(11), 619-621.

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