Key facts and the Victorian situation
What are KPC and other CRE?
Enterobacteriaceae are bacteria found in the gut, and are among the most common human pathogens, causing infections such as blood stream infections, urinary tract infections and intra-abdominal infections such as peritonitis.
Carbapenems (such as meropenem) are last line antibiotics to treat bacteria resistant to most other commonly available antibiotics. Carbapenem resistant Enterobacteriaceae are bacteria that are resistant to carbapenems which means there are very few antibiotic treatment options available for these infections.
There are many different types of CRE; they may be different bacterial species and can have different mechanisms of resistance to antibiotics. Klebsiella pneumoniae carbapenemase (KPC) is one of the mechanisms through which a bacterium can become a CRE. The bacteria acquire the ability to produce KPC which is an enzyme that breaks down carbapenems. In some cases, the genes that encode this enzyme can move between bacterial species. They have been reported worldwide and have been responsible for a number of outbreaks internationally.
Sporadic cases of carbapenem-resistant Enterobacteriaceae have been reported in Australia, though they have most often been acquired overseas. Local transmission of CRE in Australia represents a serious threat to public health. A coordinated response is required to address the risk of CRE becoming established in healthcare facilities or in the community.
Why are these organisms important?
CRE can be present in the gut of a patient without causing clinical disease, known as colonization. A subset of patients colonised with CRE may develop active infection caused by these bacteria. Infections can include, for example, urinary tract infections or blood stream infections. Infections with CRE have been associated with very high mortality rates of up to 50 per cent in some studies. Some strains of CRE were found to be resistant to all antimicrobials, known as pan-resistant CRE.
What is the situation?
Since 2012, laboratories have voluntarily submitted a selection of isolates they suspect to be CRE to the Microbiologic Diagnostic Laboratory Public Health Laboratory (MDUPHL) for characterisation. This has identified 201 patients known to have been colonised or infected with CRE in Victoria to date. This may underestimate the true number of CRE in patients as the number of isolates not referred to MDU PHL is unknown. In addition, the approach to screening and testing for CRE is likely to be affected by degree of awareness at a health service.
An increase in isolates of genetically similar KPC was identified by MDU PHL from specimens at several laboratories in Melbourne. An investigation was initiated to review all known cases of detection of KPC, in order to understand potential source(s) and patterns of transmission of this type of CRE. As a result of this detailed review of isolates since 2012, KPC has been detected in 57 patients, including in six patients in 2015.
Genetic characterisation of KPC K. pneumoniae isolates from all over Victoria has revealed a number of sporadic cases, or small clusters, that appear to be travel related. However, the majority of isolates were genetically very similar, and the most common location of identified patients in this major cluster was at two campuses of St Vincent’s Hospital Melbourne. Patients with isolates from this larger cluster who were not identified through St Vincent’s Hospital Melbourne had previous exposure to St Vincent’s in the majority of cases.
KPC are the predominant CRE bacteria identified in Victoria recently, however KPC isolates are estimated to comprise around a third of the many different CRE strains identified in several Victorian health services over the last few years. CRE are an issue for all health services and appear to be an increasing problem.
The Australian Commission of Safety and Quality in Healthcare published a national guideline in 2013 on CRE (link). The national guideline details recommendations which are the minimum standard the Department expects of all public health services and private hospitals in Victoria. The hospital circular ‘Interim Advice on Carbapenem Resistant Enterobacteriaceae (CRE)’ provides additional information and interim recommendations specific to Victoria in light of this increase in CRE detections, especially KPC.
For further information see the Department of Health & Human Services Hospital Circular Interim Advice on Carbapenem Resistant Enterobacteriaceae (CRE).June 2015.
For consumer information see the Better Health Channel factsheet