Bug Control New Zealand Ltd Infection Control Advisory Service discusses CRE, the next big bug about to hit New Zealand, and what care facilities can expect.

Multi-resistant organisms (MROs) are on the rise, and we are seeing them enter into residential care facilities from both the acute care sector as well as the community. MROs such as extended Beta lactamases (ESBLs) are on the rise every year.

A new and emerging MRO is carbapenem-resistant enterobacteriaceae (CRE). While there are no reported cases of this MRO in New Zealand to date, there are many reported cases in Australia, and given the countries’ proximity and the frequency of travel between the two, it will only be a matter of time before cases start to appear here. The main thing to remember is not to overreact. There are standard and transmission-based contact precautions to be followed that can minimise risk following a comprehensive risk assessment for each case.

What is CRE?

Enterobacteriaceae are a family of bacteria that are found in the normal human intestinal tract. Sometimes these bacteria can spread outside of the bowel and cause infection – e.g. urinary tract infection, wound infection, and pneumonia. Carbapenems are powerful antibiotics used to treat serious infections. Some enterobacteriaceae have become resistant to carbapenem antibiotics, and these are referred to as carbapenem-resistant enterobacteriaceae or CRE. The occurrence of antimicrobial resistance in these and other gram-negative bacteria is increasingly reported worldwide and has become a major threat to the provision of healthcare. In recent years, infections caused by CRE have become more common in overseas hospitals.

The carbapenem group of antibiotics (imipenem, meropenem, doripenem, ertapenem) are considered last resort antibiotics as they offer broad spectrum antibiotic cover, enabling safe and effective treatment for severe infections. CRE occur due to the acquisition of carbapenemase enzymes (i.e. carbapenemase-producing enterobacteriaceae or CPE) or less commonly arise via other mechanisms, such as porin loss. Within the enterobacteriaceae family, carbapenemases have been found most commonly in escherichia coli and klebsiella pneumoniae, although they have also been reported in other gram-negative bacteria, such as pseudomonas and acinetobacter species.

Carbapenemase-producing enterobacteriaceae pose a particular infection prevention and control risk to any healthcare or residential care facility, as they are difficult to treat, and they can more efficiently be transmitted between patients and residents within a facility. CPE have caused a number of healthcare facility outbreaks overseas.

Recently in Australia, a number of cases of CPE have been reported in people who acquired the organism overseas. Following the detection of a CRE by the pathology laboratory, the confirmation of CPE requires specialised molecular testing in a referral laboratory, which may take several days.

Risk factors for acquisition (colonisation or infection)

  • In New Zealand, the major risk factor for acquiring CRE is recent hospitalisation in a healthcare setting overseas. Hospitalisation in the Indian subcontinent, Israel, Greece, Eastern Europe, China, North America, and South East Asia appears to confer the greatest risk.
  • Within healthcare facilities in countries where CRE are endemic, risk factors include prior antimicrobial use, length of hospital stay, severity of illness, mechanical ventilation, intensive care, the presence of wounds, prior surgery, and recent transplantation.
  • The majority of people who acquire CRE are colonised rather than infected. The primary site of colonisation is the lower gastro-intestinal tract. The duration of colonisation is unknown but is possibly lifelong. CRE can survive on environmental surfaces and equipment.

Risk factors for transmission

  • Certain CRE-positive patients and residents are more likely to contaminate the environment, together with the hands of healthcare workers. These include:
  • patients and residents with diarrhoea or faecal incontinence, enterostomies, discharging wounds
  • catheterised patients and residents with CRE colonisation of the urinary tract
  • patients and residents who are incapable of maintaining their own personal hygiene.

Caregivers providing direct care to these patients and residents are at increased risk of transient acquisition of CRE on their hands if standard and transmission-based contact precautions are not strictly followed.

The routes of transmission from patient or resident are either by direct contact through carriage of CRE on the hands of caregivers or indirectly via contaminated environmental surfaces or shared equipment.

Want to know more? ‘Simple Solutions to Managing Multi Resistant Organisms’ is the topic of a series of education sessions that are being run around New Zealand by Bug Control Ltd to help your knowledge about how to manage CRE and other MROs. Most facilities over-manage residents with MROs and therefore spend valuable time and money unnecessarily.


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