The impact of multiresistant bacteria

Recent conservative figures from the European Centre for Disease Prevention and Control (ECDC) indicate that approximately four million healthcareassociated infections occur every year in Europe, which result in about 16 million extra hospital days, direct costs of approximately e5.5 billion and approximately 37,000 deaths per year. It is estimated that half of these deaths are due to infections with the seven most common multiresistant bacteria.

Why do we have resistance?

There are several reasons for the now rapidly increasing prevalence of multiresistant bacteria seen around the world. First, bacteria are masters of evolution, theoretically multiplying by 1,000 generations in as little as 10 days, and so resistance develops through selection and adaptation, in response to the use and misuse of antimicrobial agents. We also see the spread of resistant genes between bacteria and the spread of resistant organisms between people and between people and the environment. In the last form of spread, it is important to consider how we organise society (e.g. day care centres, schools, residential homes, animal husbandry and our habits, such as what we eat, where we travel and the quality of our water) and how we organise healthcare (e.g. general standards, availability of single rooms, space between beds, isolation facilities, staffing and general/hospital hygiene). In a recent community infection control programme, pre-school children were educated to use an alcohol hand rub before meals and after visiting the lavatory. Within days the problem had been solved. The necessary intellectual exertion required is minimal. Sadly, what was easy to achieve with four-year-old children proved almost impossible to reproduce with colleagues. Finally, we must remember that antimicrobial resistance sometimes ends up in overlying successful clones and that resistance (and sometimes multiresistance) then spreads like wildfire, causing epidemics and pandemics. An example of how methicillinresistant Staphylococcus aureus (MRSA) can spread and rapidly become a problem was seen in many UK hospitals in the 1990s, of which Addenbrooke’s Hospital in Cambridge was a prime example. It seemed that control measures were working in the early part of the decade, with as few as just a handful of new cases of MRSA isolates from patients reported during each six-month period. However, by 1998 these figures had soared to around 700 cases in six months.