When it comes to antimicrobial resistance, smaller, yet closer, cases can impact transmission. Credit - AKuptsova

抗菌素耐药性构成了对感染有效治疗的巨大威胁，尤其是住院患者。这些患者由于病情或已接受的程序而容易感染。随着抗生素的有效性降低，曾经良性的感染可能会威胁生命。

医院是抗生素耐药菌细菌的理想繁殖地，因为患者群体容易受到细菌感染和高抗生素使用的结合。为了保护患者免受抗性细菌的感染，医院积极试图避免对患者群体引起抗生素耐药性。

例如，可以通过筛查有携带这些细菌的风险的患者，例如那些以前被送进患有抗生素耐药性问题的医院的患者，可以避免引入。这些患者可以在他们的新医院播种新爆发，如果他们在入院后被识别和隔离，可以预防。在这方面，要制作一个已知存在问题的医院，例如大型暴发。

例如，可以通过筛查有携带这些细菌的风险的患者来完成避免引入。

We wanted to know if hospitals with a high prevalence of antibiotic-resistant bacteria, those that are likely to be included on a high-risk list, had the largest risk for the other hospitals in the country in relation to the number of patients these hospitals exchange.

我们以产生碳青霉酶的肠杆菌科（CPE）的分布为例，以研究抗性细菌的患病率与交换患者的数量之间的相互作用。CPE是一组革兰氏阴性细菌物种，可抵抗最后一些可用的抗生素，在全球医院中构成了越来越多的问题。

We estimated the regional prevalences of CPE, based on the number of CPE isolates received and confirmed by the reference laboratory at Public Health England. These prevalences were used, together with the patient flows between hospitals, to calculate the number of expected introductions for each hospital.

Despite a large outbreak of CPE in the North-West of England that caused a considerable difference in prevalence between regions, almost all hospitals could expect the majority of CPE introductions to come from their directly neighboring hospitals, rather than the high-risk ones.

The effect we found is caused by the large differences in the number of exchanged patients between hospitals.

The effect we found is caused by the large differences in the number of exchanged patients between hospitals; as a rule of thumb, hospitals in the same region exchange 100 times more patients with each other than with hospitals in different regions. The same prevalence in a neighboring hospital will, therefore, result in 100 times more received CPE colonized patients, compared to a hospital further away. So even if the prevalence far away is much higher, in absolute numbers most colonized patients are received from the neighboring hospitals. The number of introductions from hospitals far away only start to contribute substantially if the prevalence there is over 100 times higher.

The focus of control efforts is often drawn towards big outbreaks because they are more likely to be reported and perceived as a major threat. In the meantime, a larger threat is posed by the hospitals with fewer cases, which often go under-reported. This difference in reaction between the actual and the perceived threat may ultimately undermine all control efforts.

To effectively adjust control efforts to the actual threat of introductions from other hospitals, all hospitals need to have a complete picture of the current prevalence in each hospital, in particular, their surrounding hospitals, not just the hospitals with the biggest problems. This can, for instance, be achieved by performing point prevalence surveys, and actively sharing the results with the other hospitals.

Above all, hospitals need to actively collaborate in the coordination of infection prevention and control efforts, because their antibiotic resistance problems are connected through their shared patients.