Supplemental Digital Content 1: Summary of the layout, practices and procedures of the two ICUs

Hospital A / Hospital B
ICU design
Layout / 4 bays of 5 beds, 1 bay of 4 beds and 11 side rooms (all at negative pressure) / Ward A: 11 bedded unit
Ward B: 10 bedded unit including 4 side rooms (one at negative pressure)
Ward C: 3 bedded unit
Median inter-bed distance / 3.6 m / Ward A: 3.6 m
Ward B: 2.7 m
Ward C: 2.4 m
Ventilation rate / Rooms: 10-12 air changes per hour
bays: 8 air changes per hour / 6-10 air changes per hour
Infection control
Staff / A lead and five link nurses liaise with an infection control nurse / A dedicated ICU infection control nurse employed on a full time basis
Handwashing facilities
Sink, paper towels, Alcohol hand rub, Chlorhexidine, liquid soap / Ready access both hospitals (Purell hygienic hand rub; Gojo Industries)
Aprons / Worn if in proximity to patient; removed and disposed of prior to contact with shared surface; changed when moving between bed spaces
Gloves / Worn for all invasive procedures, the washing and turning of patients, contact with mucous membranes, contact and disposal of body fluids
Equipment / Common practice for staff to borrow equipment from adjacent bed areas / Common practice for staff to restock equipment from a cupboard outside the bed area
Instruments (e.g. stethoscope) / Individual instruments provided at each bed space for both hospitals
Curtains / Disposable: changed on discharge/transfer to single room or every three months, whichever the sooner. / Re-usable: changed on discharge for new admission
Sites sampled
Bed side / Bedside keyboard (Medigenic, AID Coeur d’Alene, ID, USA), bed rail, syringe driver, storage trolley drawer handle, monitor fascia, nurse hand (finger tips both hands) / As A except chart instead of keyboard
Communal / Bay telephone, apron dispenser, doctor’s hand (finger tips both hands), air (1 m³)
Media / Blood agar, oxacillin Resistance Selective Agar Base, Leeds Acinetobacter Medium, MacConkey agar with 2mg/l cefpodoxime, and from phase 2, Braziers’ contact plates (25 cm2; Oxoid Ltd, Basingstoke, UK) incubated anaerobically. Each medium incorporated 4 neutralising agents (Tween 80 (3.2g/l), histidine (0.14g/l), lecithin (0.32g/l) and sodium thiosulphate (0.8g/l))
Air sampling / Spin Air sampler (Fred Baker Ltd; Bridgend, UK); air (1 m3 ) at 100 L/min onto a 90 mm blood agar plate (Oxoid Ltd) rotated at 1 rpm. For C. difficile, 90 mm Brazier’s plate.
MRSA screening samples
Type / Nasal screening swabs / Nose/perineum screening swabs
Frequency / i) within 24 h of admission
ii) weekly thereafter
iii) on discharge from ICU / i) within 24 h of admission
ii) twice-weekly thereafter
iii) on discharge from ICU
Methodology / Rapid PCR-based screening / Rapid PCR-based screening
Confirmation via cultivation
Communication of results / Laboratory posts results electronically plus on daily microbiology ward round. / Infection control team contacts ICU infection control nurse
MRSA suppression therapy
Instigation / As soon as positive result is known / As soon as ICU infection control nurse is informed of a positive result
Duration / 5 days / 14 days
Therapy / 2% mupirocin (nasal ointment)
3 times a day
4% chlorhexidine cleanser
daily as skin wash and 3
times a week as hair wash. / 2% mupirocin (nasal ointment)
3 times a day
0.2% chlorhexidine mouthwash
4 times a day
4% chlorhexidine cleanser
daily as skin wash
twice weekly as hair wash
Test for clearance / Patient is considered to remain positive. Re-isolation of MRSA from a clinical sample prompts therapy. / Patient considered clear once 3 consecutive screening swabs are deemed negative A positive result prompts therapy to be repeated.
MRSA isolation/cohorting
Isolation of MRSA-positive patients / Yes – if single room available if not, cohorting as below
Cohorting of MRSA-positive patients / From Feb 2008, if no single rooms available, MRSA-positive patients cohorted in one bay / A two-patient cohort within the 10-bedded unit
Prophylaxis
Surgery if MRSA carrier / Teicoplanin and gentamicin / Teicoplanin and gentamicin
Other / None / All patients:
0.2% chlorhexidine mouthwash
4 times a day
4% chlorhexidine cleanser
daily as skin wash
twice weekly as hair wash
Treatment applied for 5 days then stopped for 5 days before repeating.

Supplemental Digital Content 2.

Additional information on Cleaning protocols

Three full-time and two part-time hygiene technicians were employed for the duration of the study. Each was trained in both the routine (i.e. standard) cleaning protocols (according to local hospital policy and procedures) and the enhanced cleaning regime – a total environmental cleaning system, based on microfibre technology, governed by standard operating procedures and designed to achieve microbiological control of the entire near-patient environment. This study was not a formal evaluation of microfibre which was merely used to deliver the high level environmental decontamination required.

Standard cleaning

Throughout the study, the domestic staff at both hospitals carried out their routine (i.e. standard) cleaning duties daily between 07:00 and 15:00. The nurses were expected to clean the bed area and associated equipment once a shift. However, at both sites routine cleaning by nurses was irregular and depended on the intensity of work required with a particular patient.

Enhanced cleaning regime

The team of hygiene technicians worked 7 days a week on a rota basis, with enhanced cleaning being performed between 08:00 and 16:00 plus an evening shift when high contact areas were re-cleaned. The same hygiene team was used for all enhanced cleaning at both hospitals.

Microfiber cloths were folded into quarters so as to allow eight clean areas of cloth to be available for cleaning. Microfiber cloths for use with patients with diarrhoea were separately colour coded, soaked in Actichlor Plus and folded in the same way. All cloths were then placed into plastic storage boxes.

Before commencing work, the technician washed his/her hands and put on an apron and gloves. Each bed area was divided into four zones as follows: i) the furniture and all equipment located to the left of the patient; ii) the furniture and all equipment located to the right of the patient; iii) the bed and associated components; iv) the furniture and all equipment located at the foot of the bed. The first zone included the top of pedestal, light switch, line feeder, syringe driver, computer keyboard, monitor and mouse, chart table, pens and pencils, computer table top, and chair arm rests. The second zone included the patient’s monitor, ventilator monitor, top of shelf, and oxygen and air points. The third zone included the cot rails and foot boards, control panels, rail release buttons, and mattress air unit. The fourth zone was the apron dispenser, dispensing cabinet, thermometer and holder, torch, storage trolley handles, glove dispenser, haemofiltration machine (except at Hospital B), patient controlled analgesia pump, bed warmer, and Doppler machine. Where present, the patient’s table, television and remote control were also cleaned. In practice there was variation in the equipment around each bed.

The type and amount of equipment present in each zone differed depending on the severity of illness of the patient. However, in general, four cloths were used to clean each bed area; one cloth being used for each zone, although this could vary depending on the type and/or level of contamination present. If, for example, blood was wiped up and absorbed by a cloth, that cloth would be discarded; the technician would then wash their hands and change their gloves before recommencing the clean. After cleaning each piece of equipment, the cloth was turned and/or re-folded so exposing a clean area of cloth for use on the next piece of equipment. Once all furniture and equipment had been cleaned, the technician removed their apron and gloves before leaving the bed area. Communal areas of the wider ward environment were also cleaned by the hygiene technicians. These included the telephones and computers at the nurse’s station, the medical supplies cabinet and the handles and/or push plates of the main ward/bay doors.

At the end of each shift all storage trays, boxes and other equipment were disinfected with Actichlor Plus.

To ensure the laundering process was not having a detrimental effect on the efficacy of the microfiber cloths and that the hygiene technicians were consistent in their cleaning technique and intensity, the enhanced cleaning regime was audited on a weekly basis using ATP bioluminescence (CleanTrace™ Rapid Cleanliness Test; 3M Health Care Ltd, Loughborough UK) both before and immediately (~ 10 min) after they had been cleaned. The overall bioload before and after cleaning was monitored at pre-selected sites within one random bed area each week. Audit results were fed back to the individual cleaning team members.

Supplemental Digital Content 3: Colonisation with or acquisition of other target pathogens during each study phase.

Target organism / Hospital A / Hospital B
Enhanced
cleaning / Standard cleaning / Enhanced
cleaning / Standard cleaning
Total number of admissions / 799 / 863 / 453 / 468
Acinetobacter
baumannii / Number of patients positive on admission to ICU / 2 / 1 / 6 / 4
Number of acquisitions1 / 2 / 0 / 2 / 9
Incidence density 2 / 0.48 / 0 / 0.64 / 2.89
ESBL-producing
coliforms / Number of patients positive on admission to ICU / 6 / 7 / 5 / 3
Number of acquisitions1 / 4 / 5 / 7 / 3
Incidence density 2 / 0.99 / 1.20 / 2.33 / 0.96
VRE / Number of patients positive on admission to ICU / 2 / 1 / 1 / 1
Number of acquisitions1 / 1 / 1 / 0 / 0
Incidence density 2 / 0.24 / 0.23 / 0 / 0
C. difficile / Number of patients positive on admission to ICU / 10 / 13 / 5 / 4
Number of acquisitions1 / 2 / 6 / 8 / 2
Incidence density 2 / 0.49 / 1.48 / 2.61 / 0.62

1 colonisation or infection

2 incidence density = number of acquisitions / 1000 patient days at risk

Supplemental Digital Content 4: Results of a generalized linear model used to analyse the effect of cleaning regimen, hospital environment and colonisation pressure upon patient acquisition of MRSA.

variable / odds ratio / 95% confidence interval / P-value
Enhanced cleaning regimen / 0.98 / (0.58, 1.65) / 0.93
Hospital B / 2.73 / (1.62, 4.59) / < 0.001
MRSA colonisation pressure
Lag 1
Lag 2
Lag 3 / 0.79
1.08
1.30 / (0.59, 1.05)
(0.73, 1.60)
(0.97, 1.74) / 0.10
0.70
0.08

 colonisation pressure on each of the 3 days prior to MRSA acquisition (2)

Supplemental Digital content 5. Total aerobic colony count (contact plate 25 cm²) on repeated sampling during the day

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