Gold standards for infection

The CGDent publication is more recent than SDCEP’s Drug Prescribing For Dentistry, Dental Clinical Guidance Third Edition, January 2016. It more strongly reflects the importance of antimicrobial stewardship, particularly the need to

• only use antibiotics when there is published evidence of net benefit
• use first-line antibiotics (like penicillin, amoxicillin) whenever possible.
• reserve second line antibiotics (like metronidazole, clarithromycin, azithromycin) for when first line ones are contra-indicated (e.g. allergy, interactions).
• reserve third line antibiotics (like co-amoxiclav) for cases where a medical microbiologist or consultant in infectious diseases is involved, normally in a secondary care setting (i.e. outside GDP)
• Refer treatment of some conditions traditionally undertaken in GDP to the medical profession when antibiotics are being considered (e.g. sinusitis)

These restrictions will help protect patients and the public from harms caused by unnecessary antibiotic use, combat antibiotic resistance, and reduce discharge of antibiotics into the environment.

Not all infections need antibiotics. Most localised dental/oral infections can be eradicated effectively by the body’s immune system without them, particularly when local measures (like drainage) are employed by the dental professional.

Spreading infection

Infections can spread both regionally and systemically. Spread is a sign that the immune system is unable to effectively localise and eradicate it.

Regional spread is evidenced by

• cellulitis
• local lymphadenopathy (tender or enlarged lymph nodes)
• moderate/severe swelling
• trismus (limited mouth opening)

Signs of systemic involvement include

• pyrexia (temperature > 38°C)
• lmalaise (a general feeling of discomfort, illness)

All patients presenting with an oral/dental infection should be investigated for these signs, and if present, antibiotics should be considered as an adjunct to any possible local measures.

Immunocompromised patients

Infections in patients who are immunocompromised should be treated aggressively, where possible in conjunction with their medical specialist.

Conditions that may affect immunity include:

• Diabetes
• HIV
• Chemotherapy
• Radiotherapy
• Solid organ transplants
• Tumours of haemopoietic and lymphoid tissue

In the past it was common to prescribe antibiotics to this group for localised infections. However, use of antibiotics is only indicated when there is evidence of spread, and then as an adjunct to local measures.

Negative findings

Both positive and negative findings regarding spread should be noted in the patient record. This a key component of antibiotic stewardship. It allows accurate audit of antibiotic prescribing, an essential measure for determining whether antibiotics are always offered when appropriate, and never when they are not.

Local measures for treating dental/oral infections include

• removal of the cause (e.g. extraction)
• incision and drainage

Local measures are not always appropriate in GDP. Some procedures/conditions

• may be beyond the experience of the average practitioner (e.g. removal of an infected bone augmentation graft),
• are best managed in secondary care (e.g. infected osteoradionecrosis – ORN).
• may not require immediate local measures (e.g. a cellulitis may not be drainable or immediately removable).

Delayed local measures

It is recognised that appropriate local measures, and definitive treatment, may not be possible to undertake immediately, due to patient compliance, lack of skill in the practitioner, or an uncertain diagnosis. Here referral is needed and antibiotics may be prescribed to control a localised infection, and prevent spread, while awaiting referral.

It is not acceptable to delay local measures because a practitioner is busy. Time should be made, including cancellation of routine care appointments if necessary.

Fortunately, most antibiotics are still effective against most dental infections in most dental patients.

However, resistance is always increasing, and the more antibiotics are used, the more strains resistant to that particular antibiotic develop. Resistant bacteria can subsequently transfer their resistance genes across species. For this reason, certain antibiotics are classed as

• second-line
• third line
• “drugs of last resort”

These are reserved for infections that are known to be sensitive (through microbiological testing), or for patients who are unable to tolerate the more common antibiotics (e.g. allergy, drug interactions, serious side effects).

Their restricted use will (it is hoped) delay the emergence of widespread resistance to these drugs.

When choosing which antibiotic to use:

• use first-line antibiotics (like penicillin, amoxicillin) when possible.
• reserve second line antibiotics (like metronidazole, clarithromycin, azithromycin) for when first line ones are contra-indicated.
• reserve third line antibiotics (like co-amoxiclav), and drugs of last resort (e.g. vancomycin) for cases where a medical microbiologist or consultant in infectious diseases is involved, normally in a secondary care setting (i.e. outside GDP).

Dose refers to the amount taken, and the frequency - for example 500mg every 8 hours.

If the amount taken is too little, or the interval is too long, the infection may not be adequately dealt with, and the chance of resistant organisms developing is increased.

If too much, or the interval is too short, the probability of unwanted side effects increases.

There are two types of resistance that can develop when taking antibiotics:

• Relative resistance - bacteria that only can be killed by increasing the dose
• High-level resistance - bacteria that are not affected by the drug even when exposed to very high concentrations

In most situations, it is the exposure achieved during the first dose that most affects the therapeutic outcome of an infection. “Inadequate exposure” refers to concentrations which, while killing most of the bacteria, are not enough to kill those with borderline susceptibility. These survivors can mutate further and develop high-level resistance.

The presence of these antibiotic-resistant bacteria does not mean the infection cannot be cured - the body's own immune system may suppress them where the antibiotic has failed (though this is not guaranteed).

The important thing regarding dose/frequency is to ensure the concentrations are maintained at a high enough level to be effective. A little too high is better than a little too low.

Penicillin V and VK need to be taken 6-hourly, as they are cleared from the body quite quickly. This presents practical difficulties for many patients, so to ensure that plasma concentrations are maintained at an effective level in between doses, amoxicillin or metronidazole (with an 8 hour interval) may be preferred.

For most dental/oral infections, the patient should be advised to stop taking the antibiotics when the infection has resolved.

If it does not resolve before the course has finished, they should seek an urgent review appointment

The duration of antibiotic administration needs to be kept as brief as clinically appropriate to reduce the risk of selecting for resistant (or nonresponsive) bacterial strains.

It was previously believed that "finishing the course" was necessary to ensure that "all the bascteria are killed". We now know that this is wrong - a long course actually increases the creation of antbiotic-resistant bacteria.

The environment

About 50% of an antibiotic is absorbed by the gut, and 50% excreted into the environment unchanged, where it contaminates the environment (water, soil) with low concentrations. This can speed up the development and spread of resistance.

A short course means less excretion. Patients should be advised to return un-used antibiotics to their pharmacy, which will have a waste-disposal contract for safe disposal.

If an antibiotic is going to work, it normally does so within 3 days. Patients will ideally be reviewed on the second or third day.

Discontinue the antibiotic if the temperature is normal and swelling is resolving. Failure of resolution may require further local measures, or referral for specialist advice.

Use this visit also to check whether there have been any unusual side effects, or problems taking the drug at the required intervals.

Patients should be advised to return un-used antibiotics to you, or their pharmacy, for environmentally safe disposal.

Fever and/or malaise are signs that an infection is spreading systemically. When a patient presents with an infection, the dental professional must check for these signs and record any findings - positive or negative.

Systemic infection can lead to sepsis, an urgent life-threatening condition.

If a patient is showing any signs of systemic infection, they must then have a Sepsis Check using the Sepsis Trust tool available here.

Systemic infection can lead to sepsis, an urgent life-threatening condition.

If a patient is showing any signs of systemic infection (e.g. fever, malaise), they must have a Sepsis Check using the Sepsis Trust tool available here.

The sepsis check, and action taken, must be recorded in the patient record.