Portable sensors show how bacteria spread in hospitals

A new observational study conducted in France concluded that while some types of antibiotic-resistant bacteria spread through contact between infected patients and visitors, other mechanisms may be equally important for the spread of some other common bacteria. The authors suggest that it takes more than just a hand hygiene to contain these organisms.

The study was published in the journal PLOS Computational Biology May 30, 2019.

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The emergence of multidrug-resistant bacteria is a growing threat for patients treated in hospitals and other health facilities. These bacteria often produce enzymes called extended-spectrum beta-lactamases (ESBLs) that make them invulnerable to a wide range of antibiotics. To prevent and contain the spread of such strains, we need to know more about how they spread from one patient to another.

The present study uses portable sensors to track contacts, called Near Close Interactions (CPIs), between 329 patients for eight weeks over a four-month period. The sensors were distributed to hundreds of patients and hospital health staff. They have been equipped with RFID tags to help detect contact patterns.

Patient interactions at distances less than 1.5 meters were captured at 30-second intervals. All patients were also screened weekly for the presence of ESBL-producing bacteria. Klebsiella pneumoniae (K. pneumoniae) and Escherichia coli (E. coli).

Klebsiella pneumoniae (K. pneumoniae) and Escherichia coli (E. coli) are high priority organisms for the development of new antibiotics. They are the source of one-fifth of infections transmitted during health care visits or stays and more than half of the urinary tract infections badociated with health care.

In fact, according to a WHO study, this latest bacterium is responsible for one-fifth of all healthcare-badociated infections. The presence of a blood-borne infection with a strain producing ESBL increases the risk of death by 63% compared to non-ESBL producing strains.

What did the researchers find?

In this study, the greatest number of existing or new infections to ESBL E. coli and ESBL K. pneumoniae have been found in geriatric and neurological departments, respectively. No candidate for transmission could be found in just under half of the infections. The remaining episodes of new infection during the study period were badyzed to determine contact patterns.

Most ESBL K. pneumoniae infections were found in one neighborhood while resisting E. coli quickly spread through the installation. The latter was imported 8 times more frequently than the previous one and had multiple resistance profiles.

Scientists suggest that this indicates a community origin for most of these ESBLs E. coli infections. This could also explain why no transmission candidate has been found in the contact network in many cases, as several patients may have been colonized in the community before arriving at the hospital.

Other explanations for the impossibility of finding contacts via the sensor network include antibiotic exposure revealing a latent infection, or the acquisition of the infection. plasmid infection with E. coli who had previously acquired resistance to antibiotics.

Not all infections spread by human contact

About 90% of ESBL producers K. pneumoniae was transmitted to uninfected patients through direct or indirect contact with the infected patient, but only 54% of people with ESBL E. coli. For example, the application of strict handwashing guidelines could help prevent transmission in 9 out of 10 South African countries. K. pneumoniae infections.

However, other steps, such as the use of disinfectants on potentially contaminated environmental surfaces surrounding infected patients, or the use of the appropriate type of antibiotic, would be necessary to retain ESBLs . K. pneumonia to spread. These results are consistent with previous research that shows that ESBL K. pneumoniae spreads 3 times more easily than ESBL E. coli.

E. coli is a heterogeneous organism that has several strains capable of spreading rapidly within a community. This makes long-term care facilities a potential reservoir of multidrug-resistant strains and a powerful means of disseminating these organisms in health facilities and the community at large.

The study also demonstrates that portable sensors can be used to understand how multidrug-resistant bacterial strains spread.

Of course, the study had limitations because the isolates were clbadified according to the phenotypic resistance profiles. False positives are possible with the use of CPIs as an interaction standard.

By combining digital epidemiology and rapid microbiological diagnostic tools, we may be entering a new era to understand and control the risk of hospital-acquired infection with a multidrug-resistant bacterium.

Andrey Duval, first author