Rapid increase in resistant intestinal bacteria among preschool children

Antibiotic resistance, a growing global problem, is described by the World Health Organization (WHO) as one of the main threats to our health. Every year, resistant bacteria cause millions of deaths around the world from infections that are untreatable. They make disease progression more severe and entail rising medical costs. Intestinal bacteria that produce ESBLs (extended-spectrum beta [ß] lactamases) are the most rapidly increasing source of antibiotic resistance found among patients in Sweden, although the prevalence of resistance in the Nordic countries has long been comparatively low. Outbreaks of resistant bacteria have, however, been reported at hospitals and in society at large since 2000.

ESBLs are a group of enzymes formed from bacteria. They break down a number of important types of antibiotic, rendering them ineffective. The enzymes often disperse among intestinal bacteria, commonly in the Enterobactericeae family, which can lead not only to urinary tract infections but also to abdominal and wound infections, septicaemia and meningitis. Antibiotic-resistant intestinal bacteria, as such, represent no danger to the carrier. However, it may result in problems if the bacteria give rise to an infection.

For his thesis, Johan Kaarme studied the prevalence of two important types of antibiotic resistance among healthy preschool children in Uppsala: ESBLs and vancomycin-resistant enterococci (VRE). The latter are common intestinal bacteria that have become resistant to vancomycin, an antibiotic used to treat several severe infections. The thesis also includes an investigation of the prevalence of potentially harmful viruses, bacteria and parasites in healthy children. 

In the results of the study, no vancomycin-resistant enterococci were found among the children, and symptom-free carriers of common gastroenteritis (‘stomach bug’) organisms also proved to be comparatively rare among healthy preschool children.

On the other hand, some 20% of the children proved to be carrying ESBL-producing intestinal bacteria. This represented a more than sixfold increase between 2010 and 2016.

The prevalence of antibiotic resistance is not associated with any particular areas of Uppsala: rather, preschools with high ESBL rates are dispersed across the city. Although there are preschools with no demonstrable resistant bacterial strains, there are nevertheless a handful where more than 45% of samples from the children exhibit antibiotic resistance. It is unclear how the resistance spreads within the preschools, but at several of them the children share the same resistant bacteria.

The phenomenon of antibiotic resistance is not confined to healthcare settings. Instead, resistant bacteria are all around us – in the environment, among animals and in our food, for example. This is probably due to a range of factors that include incorrect use of antibiotics both for human consumption and in animal husbandry, inadequate water purification and increased travel. In recent years, scientists have shown that resistant bacteria exist in virtually every part of the world – even regions remote from habitation, such as in the Arctic and Antarctic.

The reason for the rapid increase in ESBL-forming intestinal bacteria is unknown, since the study was carried out without knowledge of the children’s identity or possible risk factors. One implication of the findings, however, is that the healthcare services may henceforward see more infections caused by ESBL-carrying intestinal bacteria. Care services may need to become more vigilant for infections caused by resistant bacteria and, more often than they do today, grow cultures to study resistance and control treatment options. It has been known for some time that travelling abroad elevates the risk of being colonised by resistant bacteria, and one theory may be that increased travel has contributed to the increase.

Thus, parents need not be worried about these results; but the findings are of interest to the healthcare services.

To survey the prevalence of antibiotic resistance among children and adults in other segments of society and parts of Sweden, repeat studies are needed. More research is also necessary to find out how long children can carry the resistant bacteria and how high a risk of falling ill they run as a result. To slow down the rising trend of resistance, we need decisive, coordinated policy measures and research collaboration among many different academic disciplines and countries.