I have been asked many times over the last few years about
prophylactic antibiotics for patients with recurrent skin and soft tissue infections such as abscesses, boils, furuncles and carbuncles caused by Staphylococcus aureus. These patients have often been referred to an immunologist for investigation of underlying immunodeficiency and had numerous investigations but nothing wrong has ever been identified.
prophylactic antibiotics for patients with recurrent skin and soft tissue infections such as abscesses, boils, furuncles and carbuncles caused by Staphylococcus aureus. These patients have often been referred to an immunologist for investigation of underlying immunodeficiency and had numerous investigations but nothing wrong has ever been identified.
Usually in these situations the problem lies with the bacterium and not the patient. These bacteria are perfectly adapted at causing these types of infections and do so on a regular basis. The most common reason for this is the production of the toxin Panton-Valentine Leukocidin (PVL). Of the 30% of the population who have Staphylococcus aureus as part of their normal flora, approximately 2% have bacteria that can produce PVL toxin. PVL positive Staphylococcus aureus can be either MRSA or MSSA. It is
difficult to predict which will produce PVL toxin except on
the basis of a clinical history of recurrent skin and soft tissue
infections.
difficult to predict which will produce PVL toxin except on
the basis of a clinical history of recurrent skin and soft tissue
infections.
The PVL toxin is a defence mechanism used by the bacteria against the hosts’ immune system to break down white blood cells and increase the virulence of the bacterium. PVL positive Staphylococcus aureus often cause recurrent and severe skin and soft tissue infections, but occasionally they
cause more severe infections such as necrotising pneumonia, which has a 75% mortality rate.
Unfortunately PVL positive Staphylococcus aureus is very good at spreading around small groups with close contact such as schools, nurseries, nursing care homes, sporting teams and military barracks. This can lead to “recurrent infections” but in fact the individual reacquires the bacterium from someone else in the group even after having been successfully treated. The key to managing these situations is to try to eliminate the bacterium from the entire group, especially those that are carriers but are not symptomatic. Start by screening the entire group with nose swabs to detect carriage and then offer them all suppression therapy, the same regime used for Methicillin-resistant Staphylococcus aureus, see below. Then rescreen the entire group within a week and retreat if any are still positive.
Suppression Therapy
cause more severe infections such as necrotising pneumonia, which has a 75% mortality rate.
Unfortunately PVL positive Staphylococcus aureus is very good at spreading around small groups with close contact such as schools, nurseries, nursing care homes, sporting teams and military barracks. This can lead to “recurrent infections” but in fact the individual reacquires the bacterium from someone else in the group even after having been successfully treated. The key to managing these situations is to try to eliminate the bacterium from the entire group, especially those that are carriers but are not symptomatic. Start by screening the entire group with nose swabs to detect carriage and then offer them all suppression therapy, the same regime used for Methicillin-resistant Staphylococcus aureus, see below. Then rescreen the entire group within a week and retreat if any are still positive.
Suppression Therapy
| All cases PLUS For adults | Mupirocin 2% nasal ointment (Bactroban) applied to inside of the nose 3 times per day for 5 days 4% Chlorhexidine body and hair wash 1 time per day for 5 days |
Additionally during the period of suppression therapy specifically treat any group member with active skin
and soft tissue infections with Clindamycin OR Linezolid. These antibiotics have the ability to switch off toxin production and are usually enough to break the cycle of cross transmission.
The original patient can be reassured that there is nothing wrong with their immune system and that it is in fact the bacteria itself that is the problem. Managing this problem proactively protects the patient from the bacterium and also any harm caused as a result of unnecessary antibiotic prophylaxis. It takes time and effort but the benefits to the patient are worthwhile. As doctors we must be wary of using antibiotic prophylaxis as bacteria are far better at evolution than us. By giving prophylactic antibiotics (especially long courses or low doses) selective pressure is applied to the bacterium, it just evolves to survive the onslaught, develops resistance and becomes an alternative larger problem.
and soft tissue infections with Clindamycin OR Linezolid. These antibiotics have the ability to switch off toxin production and are usually enough to break the cycle of cross transmission.
The original patient can be reassured that there is nothing wrong with their immune system and that it is in fact the bacteria itself that is the problem. Managing this problem proactively protects the patient from the bacterium and also any harm caused as a result of unnecessary antibiotic prophylaxis. It takes time and effort but the benefits to the patient are worthwhile. As doctors we must be wary of using antibiotic prophylaxis as bacteria are far better at evolution than us. By giving prophylactic antibiotics (especially long courses or low doses) selective pressure is applied to the bacterium, it just evolves to survive the onslaught, develops resistance and becomes an alternative larger problem.
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