Shedding of multidrug-resistant gram-negative bacilli by colonized patients during procedures and patient care activities.

Background: Medical procedures and patient care activities may facilitate environmental shedding of health care-associated pathogens.

Methods: We conducted a cohort study of hospitalized patients in contact precautions for carriage of extended-spectrum beta-lactamase (ESBL)-producing gram-negative bacilli (N = 38) or carbapenem-resistant gram-negative bacilli (CR-GNB) (N = 22) to determine the frequency of environmental shedding during procedures and care activities. Perirectal, wound, and skin were cultured for ESBL-producing and CR-GNB. High-touch surfaces and portable equipment were disinfected before and cultured after procedures; control cultures were collected in the absence of procedures.

Results: Of 60 patients enrolled, 34 (57%) had positive perirectal and/or skin or wound cultures. For these 34 patients, 15 (44%) shed their colonizing organism to surfaces during 1 or more procedures. Patients with shedding had significantly higher concentrations of the pathogens recovered from perirectal swabs than those with no shedding (mean, 3.5 vs 2.2 log colony-forming units per swab; P < .01). Environmental shedding occurred more frequently during procedures and care activities than in the absence of a procedure (21 of 117, 18% vs 1 of 61, 2%; P < .01), and 6 of 56 (10%) portable devices used for procedures became contaminated.

Conclusions: Environmental shedding of antibiotic-resistant gram-negative bacilli occurs frequently during medical procedures and patient care activities. Decontamination of surfaces and equipment and approaches that reduce the burden of carriage could reduce the risk for dissemination.