Table 3:

Description of Cohorting Strategy by Pathogen

Author, year	COHORT AREA Separate (S) Geographic (G)		P	S	PS	Cohorting in phases (Yes or No)	DESCRIPTION of COHORTING
	S	G	Patient (P) staff (S), or both (PS)
C. difficile
Struelens, 1991		✓	✓			Y
Cherifi, 2006	✓				✓	N
Debast, 2009	✓		✓			N
Price, 2010	✓				✓	N	The cohorting ward was specifically for patients with CDI. Patients testing positive for CDI who still had ongoing diarrhea were transferred to the cohort ward on the same day. The ward had its own nursing staff and all patients admitted to the ward were transferred to the care of the infectious diseases team. All staff working on the ward wore scrubs and put on a new apron and gloves between each patient contact. A small minority of CDI patients had health needs, most usually surgical or high-dependency, which prevented transfer to the ward; however, all patients eligible for transfer to the ward were accommodated there.
Islam 2013	✓				✓	N	11 bed cohort ward; This had two four-bedded bays providing separate female and male areas, a double bay and one side-room. All patients had their own commode, stethoscope and disposable bed curtains.
Garcia-Lecona 2018	✓		✓			N	Common isolation unit (CIU)- A CIU consisted of 1 room with 4 beds was designated for CDI patients. The CIU had 1–2 nurses and 1 medical attendant per shift.
MRSA
Selkon, 1980	✓				✓	N	The unit has eight single cubicles and two double rooms, all with ante-rooms and en suite toilet and shower facilities. The windows are sealed, ventilation being provided by a plenum system in which air is released into the corridor and then passes through grilles on the doors into the ante-room and then to the patient’s room (providing 10 air changes per hour). The air is removed from the patient’s room through a central exhaust system and discharged at roof height: Each ante-room is fitted with a wash-hand basin and everyone entering the room puts on a gown and removes it on leaving this area. The nursing and ancillary staff are permanently employed on the unit.
Arnow, 1982		✓			✓	N
Duckworth, 1988	✓	✓	✓			Y	The isolation bay was located at the end of the ward and had a maximum of five patients at any one time and was open for 7 weeks. The Isolation ward was 14-bed capacity, and was opened during phase 5 of the intervention
Murray-leisure, 1990	✓				✓	Y	In 10/1998 a single unit was established
Cohen, 1991	✓		✓			Y	Cohorting was done only until 1985
Faoagali, 1992	✓	✓	✓			Y	Cohort ward was separate from main hospital, but on campus
Cox, 1995	✓				✓	N	Though the cohort area was completely separated from the ward by double doors, and had a separate team of nurses, cases continued to occur in the main ward, particularly in the adjacent bay. A vacant ward in a more isolated part of the hospital site was therefore refurbished and the patients moved there.
Mayall, 1996		✓			✓	Y	Positive patients were cohorted into two four-bed bays at one end of the ward. A four-bed bay was left vacant between these patients and other patients from whom MRSA was not isolated: this was reopened in mid-January. Previously colonized patients remained cohorted until discharge. Nurses assigned to these two bays for a single shift did not work elsewhere.
Meier, 1996		✓	✓			N
Farrington, 1998		✓			✓	Y
Fitzpatrick, 2000	✓		✓			N	Cohorting in a separate MRSA cohort ward – comprised of three open plan three-bedded areas with assisted and ambulant showering facilities, two single rooms with en suite facilities, a staff changing room with showering facilities, and a rehabilitation room, incorporating physiotherapy and occupational therapy facilities which converts to a patient recreation room after hours.
Cepeda, 2005		✓			✓
Curran, 2006		✓			✓	N	Cohort w/ in the unit
Singh, 2006		✓	✓			N
Raineri, 2007		✓	✓			Y	From 1 January 1996 to 31 December 2002, the ICU was divided into two five-bed bays. From 1 January 2003 the ICU moved to another floor, where it was structured into two single rooms, one two-bed and two three-bed bays. MRSA-positive patients, either colonized or infected, where always isolated in single rooms or cohorted in the same bay
Gilroy 2009	✓		✓			N	A cohort unit with 17 private rooms, each with a bathroom; contact precautions was only for those colonized w/ other MDRO
Khan, 2009		✓			✓	Y
Batra, 2010		✓	✓			Y
Kusachi, 2010		✓	✓			Y
Barbut, 2013		✓	✓			N
Fisher, 2013		✓	✓			N	Patients were placed in isolation or, more usually, in a designated cohort cubicle, established on each ward.
Marshall, 2013		✓	✓			N
VRE
Karanfil, 1992		✓			✓	N
Lai, 1998		✓			✓	Y
Jochimsen, 1999	✓				✓	N	Patients were cohorted on a single hospital ward with dedicated nursing staff and patient-care equipment. Patients requiring many different levels of care, from intensive care to rehabilitation, were placed on the same unit
Montecalvo, 1999		✓			✓	N
Bartley, 2001		✓			✓	N	A six-bed bay in the Infectious Diseases ward was converted into a VRE-only hemodialysis facility.
Ridwan, 2002		✓			✓	N
Sample, 2002		✓			✓	Y
Timmers, 2002		✓			✓	Y	The first cohort consisted of all “known VRE-positive” patients. Additionally, patients who had been hospitalized between November 1998 and August 1999 were considered “possibly VRE-positive”, irrespective of culture results. They were cohorted and barrier nursed. No sharing of any article between patients was allowed in this patient group. New patients, who had never been admitted to the hematology ward before, were considered to be a “true VRE negative” cohort,” and were nursed in separate rooms, without isolation precautions. Nurse cohorting: On every shift nurses were strictly allocated to either VRE-positive or -negative patients. Clinicians conducted their rounds visiting the VRE-negative patients first, followed by the “possibly colonized patients” and the VRE- positive patients last.
Christiansen, 2004	✓				✓	N	3 cohorts established - Positive patients were transferred into dedicated isolation wards where strict contact gown and glove precautions were maintained. Patients who had been in the same ward as positive patients were accommodated in designated “contact” wards. Patients who had not been admitted to Royal Perth Hospital previously during the outbreak, those who had not been in contact with a carrier, and those who had had four negative rectal swabs were placed in designated “clean” wards. Standard precautions were practiced in the latter two patient cohorts. Each cohort had dedicated nursing staff, thus ensuring that movement of nursing staff between VRE-positive and VRE-negative patients did not occur.
Mascini,2006		✓			✓	Y	P1 (6/2000–10/2000): 4 Cohorts: epidemic VRE (epiVRE) patients, roommates of epiVRE patients, wardmates of epiVRE patients, and newly admitted patients; staff cohorting in 4 cohorts; P2 (11/2000–6/2001): 3 Cohorts: epiVRE patients, possibly epiVRE patients, and newly admitted patients; staff cohorting in 3 cohorts; Preemptive isolation of all patients hospitalized in the ward between January and November 2000, regardless of culture results (patients labeled in hospital information system)
Lucet, 2007	✓				✓	N	All 14 VRE-positive patients in the hospital were cohorted in the rooms opening into one corridor and, later on, in one of the ID units. No other patients were admitted to the cohorting area. Contact precautions were reinforced for these patients according to published guidelines; staff cohorting was done as well.
Schmidt-Heiber, 2007	✓				✓	N	Patients were housed on separate hematologic wards according to their VRE status. Those with an unknown VRE status were housed on a separate ward and then grouped according to the VREscreening results. Each patient cohort was attended by a separate nursing staff.
Kurup, 2008	✓		✓			N	VRE cohorts stretched the capacity of the existing 16-bed isolation ward. Consequently, the latter was extended to a 46-bed ward by temporarily displacing an adjacent colorectal ward.
Servais, 2009	✓				✓	N
Moretti, 2010	✓				✓	Y	Establishment of a new hospital unit with 14 individual rooms exclusively for VRE patients
Morris-Downes, 2010		✓	✓			Y
Chotiprasitsakul, 2016		✓	✓			N	Each unit was divided into 3 zones: confirmed positive VRE zone, VRE-contact zone and non-contact zone. The patients in the confirmed positive VRE and VRE-contact zones had contact precautions implemented, while the patients in the non-contact VRE zone had standard precautions continued.
A baumannii
Podnos, 2001		✓			✓	N
Longo, 2005		✓			✓	N
Apisarnarnthan arak, 2008		✓	✓			Y	Cohorting in a section of the unit during period 2
Kohlenberg 2009		✓			✓	Y	Cohorting was started only during second phase
Palmore, 2011		✓			✓	N
Ayraud-Thevenot, 2012		✓			✓	N	Patients cohorted in a three-bedded area, physically separated from the rest of the unit and with dedicated healthcare workers.
Landelle, 2013	✓				✓	Y	Patient cohorted in a 6- bed isolation unit created in a medical ward and cared for by trained and dedicated healthcare workers
Alfandari, 2014	✓				✓	Y	A second cohorting sector for carbapenem resistant A. baumannii (CRAb) patients was created in an isolated 4-bed sector of the infectious diseases unit,
Apisarnarnthan arak, 2014		✓	✓			N	Cohorting of patients in one section of the unit
Cho, 2014	✓		✓			N	4 cohort rooms, of 16 beds dedicated to MDRO
Gray, 2015	✓				✓	N	A cohort ward was created
Molter, 2015		✓			✓	Y	Cohorting (started D4 of outbreak) a designated area for care of patients colonized or infected was defined in the MICU and a separate nursing team took over; cohorting of patients was established to separate patients colonized with CRAb and their contact patients (grey area) from unaffected patients (yellow area).
Gavalda, 2016	✓		✓			N	Cohorting to a unique unit; the cohorting practice was maintained during the entire post-intervention period, even when screening cultures were not systematically performed.
Gagnaire, 2017		✓			✓	N
Metan, 2019		✓			✓	N
CRE/ESBL
Ohana 2006		✓			✓	N	Carriers were cohorted in the same bedrooms or placed in single rooms
Laurent 2008	✓				✓	N	All colonized patients received cohorted care from a designated nursing staff in a dedicated 6-bed ICU, with additional nurses provided to staff this unit. After 2 weeks, the nursing staff assigned to the cohorting unit was permuted with another team to relieve the staff members from the extra workload and to maintain a high level of compliance with infection control measures.
Kochar 2009		✓			✓	N
Langer 2009		✓			✓	N	Cohorted all patients in adjacent private ICU rooms and assigned dedicated nursing staff.
Carbonne 2010		✓	✓			N	Cohorting separately case and contact patients.
Gregory 2010	✓				✓	N	Patients with infection or colonization were placed in a cohort in 1 unit with a dedicated nursing staff.
Kassis 2010		✓			✓	Y	Defined 5 distinct sections (cohorting); Nursing staff was assigned exclusively to one of the five sections.
Munoz-price 2010		✓			✓	N	Cohorted in an open, 4-patient pod. Respiratory therapists, nursing staff, and nursing aids were also cohorted during their shifts and on a rotating basis, to care exclusively for patients known to harbor KPC-producing K. pneumoniae.
Agodi 2011		✓			✓	N
Ciobotaro 2011	✓				✓	N	Clinical cases as well as carriers of CRKP were cohorted in separated locations. The cohorted carriers were treated exclusively by dedicated nursing personnel
Cohen 2011		✓			✓	Y	Cohorting of CRKP patients with dedicated nursing staff and screening of patients neighboring a patient newly identified as a carrier of CRKP, which was started in March 2007
Schwaber 2011	✓				✓	N	Placement of patients in self-contained nursing units—either single rooms or cohorts—containing all materials needed for their care and staffed by dedicated nurses on all shifts.
Palmore 2013		✓			✓	N
Sisirak 2013		✓	✓			N
Vergara-lopez 2013		✓		✓		N	Nurse cohorting
Kim 2014		✓	✓			N
Nouvenne 2014	✓				✓	Y	A 14-bed isolation ward with a staff-cohorting management was activated (10/2011–2/2012);
Viale 2014		✓	✓			N	Targeted cohorting of carriers
Hussein 2017		✓			✓	Y
Decraene 2018	✓				✓	Y	Patient and staff cohorting in dedicated CRE wards (3/2015–12/2015)
Pirs 2018		✓			✓	N
Reeme 2019	✓				✓	Y	The cohorting unit was an 8-bed hospital ward initially designed for containment of Ebola hemorrhagic fever cases and was used for cohorting KPC cases during this outbreak.
Other MDROs
Landrum 2008		✓			✓	N
Rosenberger, 2011		✓			✓	Y	Patient cohorting/enhanced isolation in ICU (until discharge): The main front entrance was closed, and all traffic was redirected through the back entrance of the unit, decreasing unnecessary flow in the “high-risk” area. Nursing staff assigned to provide care for either two isolation or two non-isolation patients, and no nurse provided care to both an isolation and a non-isolation patient. Staff rounds in the ICU were modified; Procedures and diagnostic tests were performed at the bedside without transportation out of the unit unless absolutely necessary. When a procedure outside the unit was necessary for an isolated patient, his or her exit from the unit was through the previously closed front door to avoid passage in front of the rooms of non-isolated patients
Stumpfs, 2013	✓				✓	N	Patient cohort in a special unit -the 34 beds of the unit were located in 16 rooms for adult MDRO-infected patients and 2 additional rooms for respiratory isolation. Patients were transferred to the unit when they were identified as infected or colonized with MDROs.
Wongchaoren, 2013		✓			✓	Y	8 bed cohort area in the unit, 1 nurse per shift in the area
Arruda, 2019	✓				✓	N