Some wards at Auckland's Middlemore Hospital have been declared a transmission risk area after a superbug was found in two patients.
Photo: RNZ / Claire Eastham-Farrelly
The Counties Manukau District Health Board said there is no cause for alarm but it has intensified surveillance for the antibiotic-resistant bug.
The superbug known as carbapenemase-producing enterobacteriaceae (CPE) was identified in a patient last month, then in a second patient nine days later.
Neither had symptoms or was unwell and no connection has been established between them.
The source of the infection hasn't been identified.
The DHB said most patients and visitors are not at any risk and the hospital continues as normal.
But to prevent any spread, all patients admitted for a day to surgical wards excluding maternity since 31 October will be screened if they have been or are admitted to any healthcare or aged residential care facility.
No action is needed by patients discharged home since late October.
An infectious diseases consultant, David Holland, said it's important the DHB takes every precaution to ensure it identifies anyone else who may be a carrier of CPE and, if possible, the source of the CPE.
He said that while CPE remains relatively rare in New Zealand, "there has been an increase in the number of patients presenting at the hospital with these organisms in their gut over the last few years".
Dr Holland said the bacteria can be in the gut for months to years and will cause no harm in the gut.
"There is no effective way to remove it from the gut and it may stay longer if you take antibiotics," he said.
Dr Holland said CPE can cause infection in vulnerable people if it gets into the wrong place, such as urine or a surgical wound.
The first line of defence was thorough and frequent hand-washing, especially after using the toilet and before preparing and eating food.
Dr Holland added that the DHB is working with the Health Ministry.