Carbapenemase-producing Organisms (CPOs)

What are Carbapenemase-Producing Organisms?

CPO refers to certain strains of bacteria such as Klebsiella, Escherichia coli (E. coli), Acinetobacter, and Pseudomonas that are resistant to many of the antibiotics commonly used to treat infections, including those antibiotics known as carbapenems. Carbapenems are considered one of the antimicrobial treatments of last resort. These bacteria produce an enzyme (carbapenemase) that breaks down the structure of carbapenem antibiotics.

The genes coding for cabapenemaze enzymes can be expressed after exposure to antibiotics or acquired horizontally from other bacteria. Some common examples of these genes include the New Delhi metallo-beta-lactamase-1 (NDM-1) and Klebsiella pneumoniae Carbapenemase (KPC). The NDM genes were first identified in India and Pakistan and are considered common in some health care settings. KPC was detected for the first time in the US, and is now regularly found in places such as the US, Greece, and Asia. CPOs have become common in quite a number of countries around the world.

What is the difference between bacteria referred to as CPO, CPE and CRE?

The differences depend on the type of bacteria that is being included and the mechanisms of resistance to carbapenem antibiotics.

Carbapenem Resistant Enterobacterales (CRE) refers to bacteria in the family of Enterobacterales (e.g. E. coli, Klebsiella, etc.) that are resistant to carbapenem antibiotics regardless of the method of resistance, as there are a number of different ways.

Carbapenemase Producing Enterobacterales (CPE) refers to bacteria in the family of Enterobacterales (e.g. E.coli, Klebsiella, etc.) that resist carbapenem antibiotics by producing an enzyme that blocks carbapenem antibiotics. This is determined by testing for the genes that code for these enzymes, such as KPC and NDM.

Carbapenemase Producing Organisms (CPO) refers to bacteria in the family of Enterobacterales (e.g. E.coli, Klebsiella, etc.) and those that do not belong to this family (such as Pseudomonas) but also resist carbapenem antibiotics by producing an enzyme that blocks these antibiotics. This is determined by testing for the genes that code for these enzymes, such as KPC and NDM.

Because the term CPO includes the larger group of potentially affected bacteria, PICNet and the provincial infection control community of practice are using the term CPO for their surveillance and control programs in order to capture all patients that may be carrying bacteria that are capable of spreading these antibiotic resistant genes.

Where are CPOs found?

CPOs don’t always cause infections, but often reside in the intestines of people who have become carriers of bacteria with these genetic changes. These bacteria are often acquired through health care exposures in areas where these bacteria are more common, including countries where CPOs have been identified in their health-care facilities and communities.

Some CPOs are bacteria that are commonly found in the human gut without causing harm, such as the family of Enterobacterales (including E. coli, Serratia, Kebsiella and Enterobacter). When these bacteria acquire a gene that allows them to produce a carbapenemase, they become carbapenemase-producing organisms.

Sometimes these bacteria can spread outside the gut and cause infections, such as urinary tract infections, bloodstream infections, wound infections, and pneumonia. Infections with CPOs are very difficult to treat.

What are the risk factors for CPO acquisition?

The initial risk factor is health care exposures in countries where these bacteria are commonly found. This means that individuals who have had surgery, dialysis, or been admitted to health-care facilities in CPO endemic regions are at increased risk of acquiring the bacteria and developing infections.

How are CPOs spread?

People can carry CPOs without any symptoms of illness (this is called colonization), but they still can pass the germs to other people. CPOs usually spread person-to-person through contact with infected or colonized people, or via contaminated surfaces. This can happen in both the community and health-care settings. Without proper precautions, CPOs can spread easily from person-to-person in hospitals, especially in countries where CPOs are endemic.

How are CPOs treated?

CPO colonization does not need to be treated with antibiotics. If a CPO is causing an infection, the antibiotics that will work against it are limited, but some options are still available. There are combinations of antibiotics available to effectively treat most infections. Strains of CPO resistant to all antibiotics are very rare, but have been reported. Depending on the type of infection, other therapies might be available, such as draining an abscess.

What can be done to prevent the spread of CPO?

Health care staff

To prevent the spread of CPO, health care personnel and facilities should follow infection control precautions:

• Washing hands with soap and water or an alcohol-based hand rub (ABHR) before and after caring for a patient,
• Carefully cleaning and disinfecting rooms (including sinks) and medical equipment,
• Wearing gloves and a gown before entering the room of a CPO patient,
• Keeping patients with CPO infections in a single room or sharing a room with someone else who has a CPO infection,
• Whenever possible, dedicating equipment and staff to CPO patients,
• Removing gloves and gown and washing hands before leaving the room of a CPO patient,
• Only prescribing antibiotics when necessary.

The public

To prevent the spread of CPO, the public should:

• Avoid unnecessary exposures to health care in endemic countries,
• Inform your health care professionals if you had a medical procedure done recently while travelling to an endemic country prior to a procedure (e.g. dialysis) or seeking treatment (e.g. Emergency room visit, elective surgery) in a facility in Canada.

What provincial work is being done on CPOs?

PICNet, the BC Centre for Disease Control’s Public Health Laboratory, and the BC health authorities and their facilities have been working collaboratively to identify and control CPOs in the province. A mandatory surveillance program was established in acute care facilities in July 2014 and PICNet developed various CPO surveillance elements in response to a BC Ministry of Health Policy Communique. Patients who have had a healthcare encounter outside Canada or who are suspected to be CPO carriers are tested when they seek health care services in BC. These screening programs allow hospitals to identify CPO early and reduce the spread of these bacteria to other patients through infection prevention and control practices. CPOs were designed as a reportable condition by the Provincial Health Officer in December 2016 and the mandatory surveillance was further expended to the community settings.

In addition, a Toolkit for the Management of Carbapenemase Producing Organisms (CPO) was published in September 2014, and last updated in April 2018.

What is the situation of CPO in BC health-care facilities?

The first CPO case in British Columbia (BC) was identified in 2008 from a traveler returning from an endemic country where the patient had exposure to medical procedures. Since then, CPOs have been identified among patients in both community settings and health care settings, but remain uncommon.

Through surveillance 98 new cases of CPO were identified in BC hospitals in 2015, 85 in 2016, and 109 in 2017. Most of these cases were identified in returning overseas travelers who had a health care encounter there. NDM was the predominant gene identified. Most of those persons were carriers of the CPO and did not have an invasive infection.

The emergence of carbapenemase producing organisms (CPOs) is a medical and public health concern, of which the epidemiology and control is little known in British Columbia (BC). PICNet has been working with a multidisciplinary group of representatives from each health authority and related agencies in the province to establish a provincial surveillance program for CPO. This revised protocol, endorsed by the Provincial Communicable Diseases Policy Advisory Committee, provides guidance on patient screening, data collection and reporting for CPO surveillance in BC.

Annual Report

Annual Surveillance Report for the fiscal year 2018-2019

Protocol and forms

• Surveillance Protocol for Carbapenemase Producing Organisms (CPO) and Candida auris (C. auris) in British Columbia
• Fillable CPO Surveillance Forms
  • Appendix B – Requisition Form for Carbapenemase-Producing Organisms (CPO) Testing
  • Appendix C – Surveillance form (acute care)
  • Appendix D – Addendum form for CPO or C. auris infections (acute care)
  • Appendix E – Notification of CPO or C. auris transmission investigation
  • Appendix F – Letter to ordering provider (community)
  • Appendix G – Enhanced surveillance form (community)

More information

PICNet has periodically hosted CPO Symposiums through the years. Click here for more information.