A rare antibiotic resistant "super bug" has been found in five people in the Hutt Valley.
Carbapenam Producing Enterobacteriacae (CPE) is a family of bacteria resistant to nearly all antibiotics.
Hutt Valley District Health Board infectious diseases doctor Matthew Kelly said only one out of the five people developed the infection and it was treated successfully.
The other four people were carriers. Two cases were identified in hospital and three in the community.
People should not be unduly worried, Dr Kelly said said.
"For most people who have this bacteria they wouldn't know they had it and it will cause them no harm, and there's no need to be alarmed or have any tests done.
"The bacteria can cause infection in vulnerable people if it gets into the wrong place such as in the urinary tract or a wound from surgery.
"If this bacteria does go on to cause an infection that will be just like any other infection and if they see their health care professional and get the appropriate investigations done, it's likely to be detected."
However, Dr Kelly said it was a reminder to keep up hygiene standards.
"The first line of defence against any bacteria is thorough and frequent hand washing, especially after going to the toilet, and before preparing and eating food."
Dr Kelly said about 50 people nationwide had been discovered to carry CPE this year.
"It's uncommon, but unfortunately it is increasing. This bug originates from overseas, it evolved overseas and we do see cases in New Zealand, but almost all of those cases in New Zealand have been from people who have travelled overseas."
Increased travel, globalisation and antibiotic resistance rates around the world were some of the reasons for the rise in such bugs.
There had been very few new classes of antibiotics in the past 20 years and unless that situation changed, New Zealand would encounter more bacteria that could not be treated effectively, he said.
"If we can use antibiotics wisely and responsibly then that will reduce not just the development of these bugs but the spread of these bugs."
- Ellen O'Dwyer