NHS Lothian said it took the decision in the interests of patient safety after the Pseudomonas Aeruginosa bacterium was detected in a shower and some taps last week.
A small number of patients suffered from an infection caused by the bacterium.
Around 30 procedures were initially suspended as a “precautionary measure,” but health bosses say the delays will remain in place until at least Thursday while the infection continues to be treated.
The bacteria is common and rarely affects healthy individuals, but it can be harmful to patients who are vulnerable to infection.
Sixteen additional non-elective operations are now understood to have been postponed.
A hospital spokesman said an Incident Management Team (IMT) had tested the wards and patients affected and were awaiting further results.
Professor Alex McMahon, nurse director, NHS Lothian, said: “The IMT has decided to continue the suspension of elective procedures within the specialty, until Thurdsay, until test results are confirmed.”
“We do not have the necessary assurance that we require to resume normal services.
“I know this will be disappointing and frustrating for patients, who are scheduled in for a procedure in the early part of this week, and I apologise to them for the inconvenience and disruption this will cause.”
He added: “I would reassure them, however, that patient safety is the priority in any decision we make and we are doing everything we can to return to normal as quickly as possible.”
“We have contacted all of the affected patients directly and will provide a new appointment for each of them as quickly as possible.
“In the meantime, all necessary infection control measures are in place and the situation will continue to be reviewed and monitored very closely.”