The public health watchdog has launched an investigation after the number of C difficile incidents in the English NHS rose last year for the first time since 2007.

Public Health England said it was concerned by the increase in cases of the bacterial infection, which can lead to life threatening complications in some infected patients.

According to data in this month’s NHS England board papers, 2014-15 saw a 6 per cent increase in cases of C difficile compared to the previous year.

Between April 2014 and March this year, 14,165 cases were reported across the NHS, compared to 13,361 in 2013-14.

This is the first annual rise since enhanced mandatory surveillance of the infection was introduced in 2007 as part of a major campaign by the Labour government against “hospital bugs”.

Alan Johnson, head of PHE’s department of healthcare associated infection and antibiotic resistance, said the increase in cases of C difficile was “a concern”.

However, he said it was too early to tell whether it was “just a short term fluctuation” in the downward trend which has been observed since 2007, or a “more sustained” increase.

“PHE will continue to monitor the numbers of cases and is working with the NHS and wider health service to better understand the underlying epidemiology,” he said.

Dr Johnson added: “Tackling C difficile infection continues to be a priority for PHE and across the NHS.”

While the number of C difficile incidents increased last year, it remains about 75 per cent below the number of infections in 2007-08.

The number of MRSA cases has continued to fall, decreasing by 7 per cent in 2014-15 compared with the previous year.