Reported cases of bacteria that fight off some of the more widely used antibiotic treatments have increased dramatically in recent months.
Women suffering urinal infections are thought to be especially at risk from the resistant strains – and have had to report such cases since February this year.
The Swedish Institute for Infectious Disease Control is concerned by the development as it means relatively common and usually easily treated conditions have become harder to treat, involving injections and drips, rather than a less complicated course of tablets.
The institute also fears the growth of antibiotic-resistant bacteria could result in complications for treating more serious conditions.
The bacteria are not thought to be carried in the air, but are considered to be more contagious than most.
The widespread use of antibiotics is thought to have contributed to the emergence of bacteria that are resistant to them, and assisted in their spread.