Enterobacteriaceae are Gram-negative bacteria that live, mostly naturally, in our intestines. They are also largely described in serious infections such as sepsis, peritonitis, cystitis or pneumonia, often acquired in the context of healthcare environments such as hospitals.

Antibiotics from the beta-lactam family are commonly used to treat these nosocomial infections; however, bacteria have developed mechanisms to counteract the action of beta-lactam molecules, such as the production of enzymes able to specifically hydrolyse them. These beta-lactamases are typically found in Pseudomonas aeruginosa, Klebsiella pneumoniae, E. coli and many other bacteria. They confer a high level of resistance to a wide range of beta-lactam-type antibiotics.

To face those resistant strains, carbapenems have been successfully used for years as the last-resort medicine. However, carbapenemase-producing enterobacteriaceae (CPE) have now emerged, expressing new hydrolysis enzymes to deactivate carbapenem-like molecules. CPE outbreaks in healthcare facilities leave few alternative antimicrobial solutions, and are often associated with morbidity, mortality and tremendous care costs.

RESIST tests have opened access to accurate, fast and cost-effective solutions for the identification of CPEs.

Fast identification of carbapenemases

Different types of carbapenemases have been described all over the world, the most worrying being variants of the OXA-48, KPC and NDM families. As described for other types of resistance, those carbapenem enzymes are encoded by genes present on extra-chromosomal plasmids. It facilitates exchanges between Gram-negative bacteria and explains the successful worldwide transmission of these dangerous carbapenemases.

Since warning campaigns from multiple global health organisations, almost every country in the world has now drawn up governmental guidelines for proper control and management of CPE infections in hospitals. As soon as they are identified, resistant strains should be contained quickly to avoid any spreading outside the facility, and medication should be adapted to facilitate the recovery of the patient.

A rapid detection of CPE at the clinical laboratory level is essential to prevent the spreading, isolate the facility and cure the patient. To this end, microbiological culture is largely used because of its simplicity and low cost. However, antimicrobial resistance profiles have been increasingly variable and complicated to interpret, forcing laboratories to increase the amount of analysis and, consequently, the time to result.

While confirmatory CPE phenotypic tests do exist, they require an additional day following the first antimicrobial-susceptibility testing result. Decrypting antimicrobial resistance at the DNA level using molecular techniques is an alternative solution but, unfortunately, not available in every laboratory due to the extra costs, time and staff required.

Rapid diagnostic solutions

Alternatively, RESIST tests from Coris BioConcept are lateral flow assays allowing the precise identification of carbapenemase proteins using specific monoclonal antibodies. Lateral flow assays are rapid tests, providing results in less than 15 minutes following bacterial isolation on primary microbiological cultures.

This technology is easy to handle, equipment free and low cost. Moreover, RESIST tests have proved their high performance (100% specificity and sensibility) and convenience in routine CPE analysis. Covering main variants from the three OXA-48, KPC and NDM carbapenemase families, RESIST tests have opened access to accurate, fast and cost-effective solutions for the identification of CPEs.

Coris BioConcept is making fast progress in enlarging the RESIST range of products by developing additional diagnostic tests for the rapid identification of other antibiotic resistance proteins, with the aim of providing innovative solutions for the efficient control and management of outbreaks in healthcare facilities around the world.