World Antibiotic Awareness Week - Q&A with Dr Asha Bowen
Dr Asha Bowen is a Paediatric Infectious Diseases Specialist at Princess Margaret Hospital for Children in Perth, Western Australia. She is also a Research Fellow with the Wesfarmers Centre for Vaccines and Infectious Diseases at the Telethon Kids Institute. To mark World Antibiotic Awareness Week she recently joined us for a short Q&A to talk about antibotics used for group A streptococcal infections, and important considerations when using antibiotics for rheumatic fever and rheumatic heart disease (RHD).
What is rheumatic heart disase and how does it relate to group A streptocccal infections?
RHD is caused by an abnormal immune reaction to an earlier group A streptococcal (GAS) infection. Susceptible people develop acute rheumatic fever after untreated streptococcal sore throats or skin infections. Recurrent episodes of rheumatic fever cause permanent damage to heart valves, this is known as rheumatic heart disease (RHD). Damaged valves cause heart failure, heart rhythm abnormalities and stroke. Women with RHD are at risk of death during pregnancy and delivery. Rheumatic fever and RHD can be prevented through sore throat treatment in primary care. Early diagnosis and antibiotic treatment can halt progression of RHD.
What antibiotics are recommended for management of group A streptococcal infection?
The first is called primary prevention. Penicillin antibiotics are generally recommended for treating sore throats. The WHO guidelines recommended penicillin V (liquid or tablet) or injectable, intramuscular benzathine penicillin G (BPG). Some people are allergic to penicillin – in these cases, second line antibiotics are used, usually from the macrolide class.
The second is called secondary prevention, when antibiotics are used to prevent people with a history of acute rheumatic fever or known RHD from having recurrent group A streptococcal infections. Secondary prevention is needed for the period at highest risk – usually for 10 years during adolescence. BPG is recommended for secondary prevention because one injection provides 28 days of protection against group A streptococcal infection. Tablet antibiotics do not work as well for this indication.
Is group A streptococcus becoming resistant to these penicillin antibiotics?
No, there is no evidence of group A streptococcus resistance to penicillin. The mechanism of continued susceptibility is still being researched but it is reassuring that in over 60 years of use there has been no sign of penicillin resistance emerging in group A streptococcus.
What about other bacteria, are they becoming resistant to penicillin?
Yes, other bacteria can become resistant to penicillin. At a population level this is a potential risk for reducing the number of antibiotics available to treat serious infections.
Is there a role for non-penicillin antibiotics?
Some people are allergic to penicillin and need to take other types of antibiotics. This is a safe and appropriate choice. However, sometimes alternative antibiotics are used for other reason e.g. because penicillin is inconvenient, painful or out of stock. Substituting broader spectrum antibiotics (which are effective against a wider range of bacteria) can increase costs and also antimicrobial resistance.
What is the most important consideration when using antibiotics for RHD?
It is important that antibiotics are used rationally – the right antibiotic, for the right indication over the right period of time. People at risk of acute rheumatic fever or rheumatic heart disease need antibiotics to prevent heart damage. Ensuring that they have access to needed medication is an important global health priority. Equally, ensuring that doctors and health workers know when to use antibiotics and how to use them safely helps to reduce over-use and tackle antimicrobial resistance. Clinical and antimicrobial guidelines are an important part of supporting rationale use of antibiotics.