What are Carbapenemase-Producing Organisms?

CPO refers to certain strains of bacteria such as Klebsiella, Escherichia coli (E. coli), Acinetobacter, and Pseudomonas that have acquired genes that make them resistant to many of the antibiotics commonly used to treat infections, including those antibiotics known as carbapenems.

Some common examples of these genes are the New-Delhi Metallobetalactamase (NDM) and Klebsiella pneumoniae Carbapenemase (KPC). The NDM genes originated in India and Pakistan and are considered common in some health care settings. KPC originated in the US, and is now regularly found in places such as the US, Greece, and Asia.

Where are CPOs found?

CPOs are becoming more common in quite a number of countries in the world. They 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 most likely acquired through health care exposures in areas where these bacteria are more common. These include countries where CPOs have been identified in their health care facilities.

Enterobacteriaceae (the family of bacteria that includes E. coli, Serratia, Kebsiella and Enterobacter) are commonly found in the normal human gut, without causing infection. When members of this family have acquired a gene that allows them to  produce a carbepanamase (an enzyme that blocks carbapenem antibiotics), they are called carbapenem-resistant enterobacteriaceae (CRE), or carbapenemase-producing enterobactieriaceae (CPE). CPOs include the larger group of bacteria, beyond the enterobacteriaceae family.

Sometimes these bacteria can spread outside the gut and cause serious infections, such as urinary tract infections, bloodstream infections, wound infections, and pneumonia. When these normal gut bacteria acquire the characteristics for CPO and spread outside the gut, they can cause infections that are very difficult to treat.

What are the risk factors for CPO?

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-affected locales are at increased risk of acquiring the bacteria and developing infections.

How are CPO infections treated?

CPOs are sometimes difficult to treat because they have high levels of resistance to antibiotics. However, 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 internationally. Depending on the type of infections, other therapies might be available, such as draining an abscess.

What is the situation in British Columbia health care facilities related to CPO in 2013?

Since the global increase of CPOs in the last few years, hospitals along with the Provincial Health Services Authority’s Public Health Laboratory in Vancouver have been actively testing for and monitoring CPO in BC. Facility infection control programs are quickly alerted of identified cases to prevent transmission. As well, patients who are returning from countries where they have received health care services and where these bacteria are more common are also tested for CPO when they enter a BC facility. These screening programs allow hospitals to reduce the spread of these bacteria to other patients through  infection prevention and control practices.

In 2013, 53 CPO cases were identified in the province compared to 29 in 2012 and 14 in 2011. These cases included NDM, KPC, as well as less common CPOs. Most of those persons were carriers of the CPO and did not have an invasive infection.

The increasing  number of cases between 2011 and 2013 were mostly identified in returning overseas travelers. Although transmission within facilities has occurred and contributed to this increase, identified outbreaks were  effectively controlled.

What is status of surveillance and action in British Columbia related to CPO?

In BC, CPOs are being tracked by the health authorities, who are responsible for health care facilities and infection prevention and control within these settings. Antibiotic-resistant organisms are detected in microbiology laboratories across the province. The PHSA Public Health Laboratory in Vancouver assists with specimen testing, CPO confirmation, and provincial data tracking..

What level of concern do health care officials and infection prevention and control experts have about CPO currently in BC?

As with all antibiotic resistant organisms that are found in some patients in health care facilities, we have a high level of alert but a moderate level of concern. A combination of active surveillance, aggressive infection prevention and control screening protocols and laboratory testing measures are in place to identify cases and take appropriate actions.

What can be done to prevent CPO?

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 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.

To prevent the spread of CPO, the public should:

  • Avoid unnecessary exposures to health care measures 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 is the difference between 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 Enterobacteriaceae (CRE) refers to bacteria in the family of Enterobacteriaceae (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 Enterobacteriaceae (CPE) refers to bacteria in the family of Enterobacteriaceae (e.g. E.coli, Klebsiella, etc.) that are resistant to 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 Enterobacteriaceae (e.g. E.coli, Klebsiella, etc.) and those that do not belong to this family (such as Pseudomonas) that 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.

Why is PICNet using the term CPO?

As we know that the genes for carbapenem resistance can be transferred to bacteria in the Enterobacteriaceae family and to bacteria not within this family, the term CPO includes the larger group of potentially affected bacteria. This is important for surveillance purposes, as we do not want to miss any patients that may be carrying these bacteria that are capable of spreading these antibiotic resistant genes.

What provincial work is being done on CPOs?

PICNet, in collaboration with the BC Health Authorities, has launched a provincial CPO surveillance program. Data collection began in 2014, and the first provincial CPO report is scheduled for release in February 2015. In addition, a Toolkit for the Management of Carbapenemase Producing Organisms (CPO) was published in September 2014.

More information

In March 2015, PICNet held a symposium on the topic of CPOs. You can view videos of the presentations here; the password is picnet2015.

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