HUNDREDS of people treated at Darent Valley Hospital have been contacted by doctors after two patients contracted drug-resistant strains of tuberculosis.

The Kent and Medway Health Authority has written to about 300 patients and 75 of them, who have weaker immune systems, have been offered screenings.

Around 300 members of staff, including agency nurses, have also been contacted.

The patients are those who were admitted to Linden Ward between February 22 and the end of July while two men, one aged 41, the other 42, were being treated for multi-drug resistant tuberculosis (MDRTB).

The hospital at Darenth, near Dartford, had had been treating a case of MDRTB when it was later discovered another patient in same ward had the same strain.

It is not known how they contracted the disease or if one caught it off the other. But in a letter to patients, the authority's clinical director, Dr Mathi Chandrakumar, said: "I can assure you however, it is very unlikely that you have acquired the infection as studies of a similar nature in the past have shown that on screening a large number of people who are contacts of cases, only one, or two cases, have been rarely identified."

He told a press conference that people had no cause for alarm and the measure was merely "precautionary".

He said: "Only about a quarter of the patients we have written to will have been at any risk at all. They will have had to be in close proximity for some time with one of the two patients with TB and also had their immune systems working poorly.

"This sort of thing has happened before in other hospitals and a very small number of people turned out to have been infected - almost always none."

He explained how a similar exercise was carried out at another Kent hospital during which 500 patients were contacted but none had been infected.

Dr Chandrakumar added: "We are offering immediate screening to all those people at any sort of risk. If anyone is infected then we can start a course of treatment straight away."

MDRTB is no more infectious than other strains of TB but it is rarer and takes longer to treat with different antibiotics. There are between 40 and 50 cases of TB in Kent every year.

A special helpline to answer patients' queries can be reached on 0845 4647.