Rapid Spread of Multidrug-Resistant Gram-Negative Bacteria in a COVID-19 Hospital Care Unit

One nurse looking at the medical ventilator screen. ICU COVID ward
Study authors reported a single-center experience where MDR GNB spread within a unit dedicated to COVID-19 patients.

Multidrug-resistant (MDR) gram-negative bacteria (GNB) rapidly spread among patients treated in a SARS-CoV-2 dedicated care unit, according to findings published in Emerging Infectious Diseases.

Study authors reported a single-center experience where MDR GNB spread within a unit dedicated to COVID-19 patients. The facility had COVID-19 patients in 2 intensive care units (ICU) and 1 step-down unit with closed, negative-pressure. Patients in the ICU were often in shared spaces. Staff did not change personal protective equipment between attending patients. In the case of identified resistant organisms, staff were instructed to wear 2 layers of gowns and remove the outer layer after contacting that patient.

The hospital performed routine weekly surveillance for resistant bacterial strains. In mid-May, 4 patients were identified to have MDR Escherichia coli (E coli) in 1 of the ICU. Study authors reported that between 9 and 11 weeks, there was a hospital-wide increase of MDR GNB , likely driven by the cases of E coli. Additional surveillance identified cefepime-resistant E coli, MDR Pseudomonas aeruginosa (P aeruginosa), and MDR Acinetobacter baumannii (A baumannii).

At week 12, all patients in the 3 COVID-19 wards were assessed for bacterial strains. Among the 29 patients, 18 had resistant GNBs. Public health authorities were notified, and patients were assessed biweekly for infection status.

Between April 16 and July 15, a total of 71 patients tested positive for a resistant GNB (E coli, n=44; P aeruginosa, n=27; A baumannii: n=27). More than a third of these patients (n=24) had coinfections with resistant GNBs. Patients were treated with antibiotics (97%) and received corticosteroids (73%), extracorporeal membrane oxygenation support (42%), renal replacement therapy (38%), remdesivir (35%), and tocilizumab (20%). A total of 23 of these patients died.

The E coli strains were found to belong to 3 related groups, suggesting rapid transfer from patient to patient. Transmission of P aeruginosa primarily occurred in 1 of the ICU and A baumannii in the other. These resistant strains were likely transferred from the ICU to the step-down unit.

The study authors attributed the infection spread to double occupancy of patients in the ICU and low compliance with hand and glove hygiene. Furthermore, to limit staff exposure, ancillary services, such as cleaning and stocking, were transferred to unit staff.

To ameliorate this outbreak, double occupancy was discontinued, hand and glove hygiene was frequently promoted, and high-touch surfaces were disinfected more regularly.


Patel A, Emerick M, Cabunoc M K, et al. Rapid spread and control of multidrug-resistant gram-negative bacteria in covid-19 patient care units. Emerg Infect Dis. 2021;27(4). doi:10.3201/eid2704.204036