JMM Editor's Choice: membrane permeability in carbapenem resistance

Posted on February 7, 2020   by Microbiology Society

The Journal of Medical Microbiology (JMM) is a journal published by the Microbiology Society, focused on providing comprehensive coverage of medical, dental and veterinary microbiology and infectious diseases; including bacteriology, virology, mycology and parasitology. This month, Dr Tim Inglis discusses the paper 'A simple phenotypic test for detecting the contribution of outer membrane permeability to carbapenem resistance' which was selected as Editor’s Choice from the January issue.

Pinet and colleagues have come up with a simple test for a form of antibiotic resistance that was previously difficult to identify in some bacteria. Resistance to carbapenem antimicrobials is the result of a combination of mechanisms that include changes in the bacterial cell membrane. The method described here uses a chemical treatment to increase cell membrane permeability and confirms that some antimicrobial resistance in Gram-negative bacteria is due to membrane alterations.

A simple phenotypic test for detecting the contribution of outer membrane permeability to carbapenem resistance

The emergence and spread of carbapenem-resistance in Gram-negative bacteria is a worrying threat for human health and urgently requires the development of tests to identify the underlying resistance mechanism. Enzymatic and membrane barriers are the main mechanisms involved in resistant isolates. Several tests have been developed to detect the presence of the enzymes which break down carbapenems (known as carbapenemases) but there is no simple test to identify how membrane impermeability is involved in resistance.

In our paper, a phenotypic test is described for detecting membrane-associated mechanisms of carbapenem resistance in various Enterobacteriaceae. The ease, sensitivity and specificity of this test should allow its implementation in microbiology labs and clinical settings.