Active screening and patient-placement and cohort-placement strategies to decrease carbapenem-resistant gram-negative bacilli colonization and infection in pediatric patients: A 5-year retrospective observational study in China

Carbapenem-resistant gram-negative bacilli (CR-GNB) colonization screening was initiated across high-risk departments (PICU, NICU, neonatal wards, and hematology departments) in January 2017, and several CR-GNB cohort and patient-placement strategies were introduced throughout the hospital in January 2018. The colonization and infection rates decreased to varying degrees from 2017 to 2021.

The Children's Hospital of Fudan University is an 800-bed, tertiary-care, teaching hospital comprising 3 intensive care units (ICUs, each with 40-60 beds), 12 surgical and 16 medicine wards.Patients under 18 years of age are considered pediatric.Most patients are cared for in 5-bed rooms in medical and surgical wards.ICUs are organized in open spaces, with a nurse-to-patient ratio of 2.5.
A project to decrease CR-GNB nosocomial infection incidence was initiated in 2017.CR-GNB colonization screening in the pediatric ICU, neonatal ICU, neonatology and hematology departments (hereafter referred to as high-risk departments) was implemented in January 2017. 4All CR-GNB-positive patient isolation and cohort-placement strategies were executed across the entire hospital beginning in January 2018.Other basic infection precaution bundle measures were implemented before 2017.
The study was approved by the Ethics Committee of the Children's Hospital of Fudan University, Shanghai, China (no.2021-372).

Basic infection precaution bundle measures
Contact precautions, including hand hygiene, surgical masks, hats, use of gowns and gloves along with patient and staff cohort placement, were implemented once CR-GNB was detected in a patient.Hand hygiene adherence and environmental cleaning and disinfection qualification rates (ie, number of environmental samples without positive culture divided by the total number of environmental samples) were monitored.Previously published definitions of hospital-associated infection and colonization were used. 5,6eek thereafter during admission.Repetitive screening of CR-GNB colonized patients was conducted weekly during hospitalization.

Patient isolation and cohort placement program
Beginning in January 2018, 4 types of patient placement were used for patients known to be colonized or infected with CR-GNB.Single-room placement (type A) refers to 1 patient in 1 room.Same-room placement (type B) refers to placement of patients who were infected or colonized with the same CR-GNB in the same room.Same-area placement (type C) means patients with the same CR-GNB were placed in cohorts in the same area of a multibed room with use of partition barriers.No cohort placement (type D) refers to placing patients with or without CR-GNB or with different CR-GNB in the same room without any attempt to group patients with the same CR-GNB status.Curtains were used between beds.

Microbiological methods
CR-GNB culture, identification, and antimicrobial susceptibility tests were performed as previously described. 4Clinical information for patients with CR-GNB was systematically retrieved from electronic medical records.

Statistical analysis
All data are expressed as rates for categorical variables.Comparison of rates between groups were performed using the χ 2 test; P <0.05 was regarded as statistically significant.All statistical analyses were performed using SPSS version 21.0 software (IBM, Armonk, NY).

CR-GNB-positive patients and use of isolation and cohorting strategies
Between 2017 and 2021, 5,078 CR-GNB-positive patients were identified: 4,161 in high-risk departments and 917 in non-highrisk departments.Among them, 2,016 were identified by clinical culture, 2,711 by screening, and 351 by both screening and positive Compared with the previous year, the use of placement types A and B increased in 2020 and 2019 in high and non-high-risk departments, respectively (all P < .05)(Fig. 1

and Supplementary Table S1 online).
We detected no significant change in the hand hygiene compliance rate or the environmental cleaning and disinfection qualification rate (P >.05) (Supplementary Table S2 online).

CR-GNB colonization prevalence in high-risk departments
From 2017 to 2021, >20,000 patients were screened >50,000 times in total, with detection of 2,711 CR-GNB-positive patients.Active screening was mainly concentrated within 48 hours of admission (Supplementary Table S3 online).Each year, CR-GNB colonization prevalence in the upper-respiratory tract and the intestinal tract significantly increased, with an increased length of hospital stay.However, colonization prevalence decreased from 2017 to 2021 among patients in all duration-of-hospitalization categories except the 3-7-day hospitalization group (P < .001)(Fig. 2 and Supplementary Table S4 online).

CR-GNB nosocomial infection incidence
Nosocomial CR-GNB infection was identified in 530 patients: 422 in high-risk departments and 108 in non-high-risk departments.The nosocomial infection incidence showed an overall downward trend (all P <0.001) in both the high-risk and non-high-risk departments.Compared with the previous year, the CR-GNB nosocomial infection incidence in high-risk departments decreased in 2018 and 2020 and in non-high-risk departments in 2019 (all P < 0.05) (Fig. 2 and Supplementary Table S5 online).

Microbiological data
The detection rates (from both the high-risk and non-high-risk departments) of carbapenem-resistant Klebsiella pneumoniae, carbapenem-resistant Acinetobacter baumannii and carbapenem- clinical culture.Also, 3,948 CR-GNB-positive patients (1,208 by clinical culture, 2,438 by screening, and 302 by both screening and positive clinical positive) received different types of patient placement between 2018 and 2021.The use of placement types A and B increased in high-risk and non-high-risk departments.

Fig. 1 .
Fig. 1.Percentage of patients with carbapenem-resistant gram-negative bacilli (CR-GNB) cared for using each of 4 isolation and cohort-placement strategies: 2018-2021(%) Various CR-GNB patient placements were performed in (A) high-risk departments (pediatric ICU, neonatal ICU, neonatal and hematology departments) and (B) non-high-risk departments.The proportion of patients managed using placement type A (isolation) or B (cohort placement) increased in high-risk departments and non-high-risk departments.Note.Type A, single-room placement; type B, same-room placement; type C, same-area placement; type D, no cohort placement.*P <.05, comparison of patient placement type between years.# P <0.05 compared with the previous year.

Fig. 2 .
Fig. 2. Carbapenem-resistant gram-negative bacilli (CR-GNB) colonization prevalence, nosocomial infection incidence and detection rate (%).The (A) upper respiratory and (B) intestinal tract CR-GNB colonization prevalences, (C) nosocomial infection incidence, and (D) detection rate decreased (P <0.001).*P < 0.05, comparison between years.# P < 0.05, compared with the previous year.The nosocomial incidence rate is the number of new nosocomial infection cases divided by the number of patients in the hospital during the observation period×100%.The CR-GNB detection rate is the number of CR-GNB positive clinical isolates divided by the number of gram-negative bacilli-positive clinical isolates×100%.