Eleven water outlets in an East Kent hospital have tested positive for legionella after a patient developed Legionnaire’s disease.

The patient, who is still in hospital two months after becoming infected, tested positive after being transferred to St Thomas’ Hospital for extracorporeal membrane oxygenation treatment in October. The patient had been an inpatient on the Minster ward at Queen Elizabeth, the Queen Mother Hospital in Margate, part of East Kent Hospitals University Foundation Trust.

Patients who were on the Minster ward at the same time have been traced and contacted, and two who shared a bay with the infected patient have tested negative for legionella.

However, the same subgroup of legionella was then identified from water samples on the ward. In total, five water outlets on Minster, four on Seabathing and two on Bishopston wards tested positive.

Research by the Nuffield Trust earlier this year showed East Kent has someof the largest backlog maintainence costs in the country, with £30m designated “high risk”. It allocated £625,000 to legionella work this year.

The trust – which has commissioned an independent review of control measures and testing – said remedial work has been carried out and this will be followed by hyperchlorination of the affected parts of the water system. Work carried out included removal of redundant pipework and replacement of some taps. Its statement said: “We routinely regularly monitor the water systems. We have tested this wing of the hospital extensively and are undertaking remedial work where necessary.”

Legionella bacteria cause serious illness – including Legionnaire’s disease, a type of pneumonia. They can multiply in hospital water systems and are then inhaled from water droplets in the air.

A handful of cases are acquired from hospital water systems in the UK each year but the bacteria can be difficult to eradicate. Two patients died – and others were infected – at Basildon Hospital between 2007 and 2010, leading to the trust being prosecuted for taking insufficient steps to protect the public. The trust spent £3m trying to control the bacteria and at one point sought the help of the US’s Centre for Disease Control to eradicate it.