One hundred years ago, many healthcare- associated infections (HAIs) had an exogenous origin, which means they were caused by micro-organisms from other patients, healthcare workers or the hospital environment. A smaller proportion was due to endogenous micro-organisms from the patients' own microbial flora. Meanwhile, many improvements have been achieved. The majority of devices used for diagnosing and treating the patients are now single- use items. The disinfection and sterilization measures used for reprocessing the remaining devices are on a very high safety level (at least in high-income countries) and cross- transmission via instruments is a very rare seldom event. Hand hygiene has also improved substantially. We have observed an increase in hand rub consumption of more than 100% during the last 12 years in Germany. For these measures the ‘one size fits all approach’ is appropriate because they have to be applied for all patients independent of their diseases and pathogens.

Today, we see a small percentage of exogenous HAIs. The majority of HAI have an endogenous origin. Of course, it is still necessary to focus on basic or standard infection-control measures to prevent transmission of micro-organisms. However, the majority of HAIs have an endogenous origin now. Thus our measures should not only focus on preventing transmission of microorganisms, but also on prevention of infections. Therefore, a personalized infection prevention approach is now appropriate and examples will be presented.

一百年前，许多医疗保健相关感染（HAI）都是外源性的，这意味着它们是由其他患者，医护人员或医院环境中的微生物引起的。较小的比例是由于患者自身微生物菌群中的内源微生物引起的。同时，已经实现了许多改进。现在，用于诊断和治疗患者的大多数设备都是一次性用品。用于对剩余设备进行再处理的消毒和灭菌措施处于很高的安全级别（至少在高收入国家/地区），并且很少通过仪器进行交叉传输。手部卫生也大大改善。在过去的12年中，我们发现德国的手擦消耗量增长了100％以上。

今天，我们看到少量的外源性HAI。HAI的大多数具有内源性。当然，仍然有必要关注基本或标准的感染控制措施，以防止微生物的传播。但是，大多数HAIs现在具有内源性。因此，我们的措施不仅应侧重于防止微生物传播，而且还应侧重于预防感染。因此，现在适合采用个性化的感染预防方法，并给出示例。