In the JournalsPerspective

Carbapenem-resistant A. baumannii colonization persists for months

At one Israeli hospital, screening readmitted patients with prior positive clinical cultures for carbapenem-resistant Acinetobacter baumannii, or CRAB, showed that CRAB colonization was persistent for up to 285 days.

“Furthermore, we found widespread contamination of persistent carriers' immediate environment,” Amir Nutman, MD, MPH, a physician at Tel Aviv Sourasky Medical Center and the National Center for Infection Control and Antibiotic Resistance in Tel Aviv, told Infectious Disease News. “These patients may be the source of hospital outbreaks if not identified early and put on contact isolation upon return admission to prevent transmission of CRAB.”

CRAB is a leading cause of deadly health care-associated infections, but there is limited information regarding the “natural history of carriage and risk factors for extended duration of carriage,” Nutman and colleagues wrote.

Between June 2015 and November 2017, they researchers “evaluated the risk of CRAB carriage upon first readmission among patients previously diagnosed with CRAB.” The study included 38 adult patients with a clinical CRAB culture during a prior hospitalization. Patients were required to be screened within 7 days upon first readmission, and samples were collected from both patients and their immediate surroundings.

Nutman and colleagues observed a median of 59 days from discharge to readmission (interquartile range, 35-147) and a median of 2 days from readmission to screening. They reported that 31.6% (n = 12) of cultures were positive for CRAB.

Compared with patients who screened negative, patients with a positive culture were more likely to have been admitted with an infection-related diagnosis (75% vs. 38.5%; P = .04), to have arrived from an institution (66.7% vs. 23.1%; P = .01) and to have a feeding tube (41.7% vs. 7.7%; P = .02), the researchers reported.

Among the beds of the 12 patients with positive cultures, 11 were positive for CRAB. Additionally, 50% of cabinets and 57% of medical equipment associated with these patients were positive for CRAB.

Up to 58 days after discharge, the risk for CRAB carriage was 42% (95% CI, 24%-59%). Up to 141 days after discharge, it was 33% (95% CI, 17%-51%) and up to 285 days, the risk was 14% (95% CI, 3%-34%), Nutman and colleagues reported.

“Screening for CRAB upon readmission is feasible and may be warranted in specific settings; however, screening guidelines are beyond the scope of this study,” Nutman said. “Further research is needed in order to build evidence on which to base CRAB screening recommendations.” – by Marley Ghizzone

Disclosures: The authors report no relevant financial disclosures.

At one Israeli hospital, screening readmitted patients with prior positive clinical cultures for carbapenem-resistant Acinetobacter baumannii, or CRAB, showed that CRAB colonization was persistent for up to 285 days.

“Furthermore, we found widespread contamination of persistent carriers' immediate environment,” Amir Nutman, MD, MPH, a physician at Tel Aviv Sourasky Medical Center and the National Center for Infection Control and Antibiotic Resistance in Tel Aviv, told Infectious Disease News. “These patients may be the source of hospital outbreaks if not identified early and put on contact isolation upon return admission to prevent transmission of CRAB.”

CRAB is a leading cause of deadly health care-associated infections, but there is limited information regarding the “natural history of carriage and risk factors for extended duration of carriage,” Nutman and colleagues wrote.

Between June 2015 and November 2017, they researchers “evaluated the risk of CRAB carriage upon first readmission among patients previously diagnosed with CRAB.” The study included 38 adult patients with a clinical CRAB culture during a prior hospitalization. Patients were required to be screened within 7 days upon first readmission, and samples were collected from both patients and their immediate surroundings.

Nutman and colleagues observed a median of 59 days from discharge to readmission (interquartile range, 35-147) and a median of 2 days from readmission to screening. They reported that 31.6% (n = 12) of cultures were positive for CRAB.

Compared with patients who screened negative, patients with a positive culture were more likely to have been admitted with an infection-related diagnosis (75% vs. 38.5%; P = .04), to have arrived from an institution (66.7% vs. 23.1%; P = .01) and to have a feeding tube (41.7% vs. 7.7%; P = .02), the researchers reported.

Among the beds of the 12 patients with positive cultures, 11 were positive for CRAB. Additionally, 50% of cabinets and 57% of medical equipment associated with these patients were positive for CRAB.

Up to 58 days after discharge, the risk for CRAB carriage was 42% (95% CI, 24%-59%). Up to 141 days after discharge, it was 33% (95% CI, 17%-51%) and up to 285 days, the risk was 14% (95% CI, 3%-34%), Nutman and colleagues reported.

“Screening for CRAB upon readmission is feasible and may be warranted in specific settings; however, screening guidelines are beyond the scope of this study,” Nutman said. “Further research is needed in order to build evidence on which to base CRAB screening recommendations.” – by Marley Ghizzone

Disclosures: The authors report no relevant financial disclosures.

    Perspective

    People remain colonized for long periods of time with this multidrug-resistant organism.

    The risk factors for remaining colonized in these patients who are readmitted are similar to what we see with other multidrug-resistant organisms, so there is no real surprise.

    In terms of screening, I think the data are not strong enough to make a public policy statement, and it requires a little bit more before we move forward. Part of it the information comes from an Israeli study. Israel is a country where carbapenem-resistant A. baumannii has been endemic. Whereas if you look at North America, there are several geographic regions or in certain populations where it is endemic but there are other areas where these organisms are emerging. In fact, in some regions of the United States, including where I work, these organisms are emerging. At this point, we do not have enough data to make sweeping guidelines given there are few studies and the epidemiology varies. If we wanted to develop preliminary guidance, we would have to stratify by the prevalence of these organisms in different regions, and potentially populations, to make them cost-effective and sensitive to the patient population, and available resources when they are applied in a widespread fashion.

    This study includes only 38 patients. It is very tantalizing data, but I think we have to be careful before we make too many widespread conclusions.

    We need to have more studies like this that corroborate the findings. We, as a community, need to really advocate for more extensive epidemiological work such as this to really understand the roles that all kinds of different infection prevention interventions play, included screening in the management and care of patients. So, these findings may apply or may not apply in settings where you do not have the density of CRAB that you have in Tel Aviv. For instance, is this a reasonable strategy that applies to nursing home patients who are getting admitted vs. children who are aged younger than 2 years? We really need to invest in this kind of research to answer important questions and develop relevant and pragmatic policies that prevent transmission of these multidrug resistant organisms and extension in all kinds of different settings.

    • Trish M. Perl, MD, MSc, FIDSA, FSHEA
    • Member, Infectious Diseases Society of America
      Chief of infectious diseases,
      Jay P. Sanford Professor of Infectious Diseases,
      University of Texas Southwestern

    Disclosures: Perl reports no relevant financial disclosures.