Transmission of health care-associated infections from roommates and prior room occupants: a systematic review

Figures & data

Table 1 Assessment of study quality

Quality measurea	Yes (%)	No (%)	Cannot determine	Not applicable
1. Is the hypothesis/aim/objective of the study clearly described?	18 (100)	0	0	0
Population, intervention or exposure, and outcome included? Yes=1; No=0
Note: Score may be based on study’s main aim
2. Are the main outcomes to be measured clearly described in the introduction or methods section?	17 (94)	1 (6)	0	0
Enough information provided to replicate study? Yes=1; No=0
3. Are the characteristics of the patients included in the study clearly described?	18 (100)	0	0	0
General patient population and inclusion/exclusion criteria described? Yes=1; No=0
Note: Descriptive statistics not required
4. Is exposure of interest clearly described?	15 (83)	3 (17)	0	0
Enough information provided to replicate study? Yes=1; No=0
Note: Score based on exposure of interest (ie, prior room occupant and/or roommate infection status)
5. Are the distributions of principal confounders in each group of subjects to be compared clearly described?	Most described: 13 (72)	0	0	0
Most clinically relevant characteristics described=2; only a few general patient characteristics described=1; no characteristics described=0	Few described: 3 (17)
6. Are the main findings of the study clearly described?	18 (100)	0	0	0
Results presented for all proposed analyses and outcome measures? Yes=1; No=0
7. Does the study provide estimates of the random variability in the data for the main outcomes?	18 (100)	0	0	0
Confidence intervals, p-values, or other measures of standard error included? Yes=1; No=0
Note: Score based on analyses for roommate and/or prior room occupant exposures
8. Have the characteristics of patients lost to follow-up been described?	2 (11)	0	0	16 (89%)
If loss to follow-up is implied, are patients described or compared to those who participated? Yes=1; No=0
Note: If loss to follow-up not mentioned by authors, item scored as “not applicable” and removed from denominator
9. Have actual probability values been reported for the main outcomes except where p<0.001?	18 (100)	0	0	0
Yes=1; No=0
10. Were patients selected in a way that is representative of the source population the authors identified in the inclusion/exclusion criteria?	16 (89)	0	2 (11%)	0
All patients identified in the source population included=1; certain patients included in the source population systematically excluded (eg, patients who died, were transferred, refused participation, etc)=0
Note: Zero was scored if authors did not provide enough information to determine representativeness
11. Were the staff, places, and facilities where the patients were treated representative of the treatment the majority of patients receive? Facility similar to other institutions of the same type?	17 (94)	0	1 (6%)	0
Yes=1; No=0
Note: Zero was scored if authors did not provide enough information to determine representativeness
12. If any of the results of the study were based on “data dredging”, was this made clear?	0	0	2 (11%)	16 (89%)
All subgroup analyses described in methods section or noted as post hoc analyses=1; unplanned subgroup analyses presented and not noted as post hoc=0
Note: If study included no subgroup analyses, item scored as “not applicable” and removed from denominator
13. Do the analyses adjust for different lengths of follow-up of patients, or in case–control studies, is the time period between the intervention and outcome the same for cases and controls?	8 (44)	6 (33)	0	4 (22%)
If follow-up is differential between groups, was this controlled for in the design or analysis? Yes=1; No=0
Note: If follow-up is same for all patients, item scored as “not applicable” and removed from denominator
14. Were the statistical tests used to assess the main outcomes appropriate?	15 (83)	3 (17)	0	0
Statistical tests minimally appropriate for the data and research questions? Yes=1; No=0
15. Were the main outcome measures used valid and reliable?	16 (89)	1 (6)	0	1 (6%)
Systematic, repeatable methods of case finding and appropriate lab definitions used? Yes=1; No=0
Note: Zero was scored if authors did not provide enough information to assess outcome measures
16. Were the patients in different intervention groups or cases and controls recruited from the same population?	18 (100)	0	0	0
Yes=1; No=0
17. Were the study subjects in different intervention groups or cases and controls recruited over the same period of time?	18 (100)	0	0	0
Yes=1; No=0
18. Was there adequate adjustment for confounding in the analyses from which the main findings were drawn?	9 (50)	6 (33)	3 (17%)	0
Key confounders included in multivariable models? Yes=1; No=0
Note: Score based on exposure of interest (ie, prior room occupant and/or roommate infection status)
19. Were losses of patients to follow-up taken into account?	1 (6)	1 (6)	16 (89%)	0
If loss to follow-up is reported, is an appropriate statistical method used to account for this? Yes=1; No=0
Note: If no loss to follow-up is reported, item scored as “not applicable” and removed from denominator. Zero was scored if authors did not provide enough information to assess loss to follow-up
20. Did the study have sufficient power to detect a clinically important	0	4 (22)	14 (78%)	0
effect where the probability value for a difference being due to chance is <5%?
Power calculation included and adequate power reported=1; power calculation included and inadequate power reported or no power calculation mentioned=0
Note: Score based on exposure of interest (ie, prior room occupant and/or roommate infection status). Zero was scored if authors did not provide enough information to assess power

Note:

a Data collection tool from Downs and Black.²⁴

Figure 1 Identification, screening, eligibility, and inclusion of articles according to the PRISMA guidelines.

Notes: Three hundred and thirty articles were identified by database search and no additional records were identified from other sources. No duplicates were identified.
Abbreviation: PRISMA, Preferred Reporting Items for Systematic Reviews and Meta-Analyses.

Figure 2 Findings of studies investigating the association between health care-associated infection or colonization and exposure to infected or colonized roommates.

Notes: Studies reporting significant positive associations are represented in black circles and those reporting significant negative associations are represented in white circles. Studies that did not find statistically significant associations are represented in gray circles. Circles display study authors, setting, investigation of endemic versus epidemic pathogen, and quality score.

Table 2 Summary and quality assessment of studies reporting associations between health care-associated infection and exposure to infected or colonized roommates

Author, quality score	Study period	Setting	Design	Subjects	N	Outcome	Exposure	Analysis	Results
Auerbach et al^Citation25 Score: 83%	August 1989–February 1990	50-bed nursing home, North Carolina	Outbreak investigation and case–control	All residents who underwent diagnostic testing for GAS, excluding those who died from causes other than GAS	37 roommate pairs	Symptomatic or asymptomatic GAS infection detected by culture or serology	Roommate w/symptomatic or asymptomatic GAS infection	Two-tailed Fisher’s exact test	26 pairs concordant uninfected, 6 concordant infected, 5 pairs discordant p=0.0009
Bass et al^Citation41 Score: 83%	March 2010–October 2010	34-bed hematology–oncology ward in 427-bed tertiary care teaching hospital, Melbourne, Australia	Quasi-experimental	All pts w/neg VRE rectal swab upon admission and no known history of VRE	439 pts	Incident VRE colonization detected by rectal surveillance culture	Roommate w/VRE infection or colonization	Cox proportional hazard adjusted for prior bed occupant status and study intervention phase	HR: 18.8 (5.4–66.2)
Bruce et al^Citation26 Score: 50%	August 1994–October 1996	Special Immunity Service ward for HIV-pos pts, Grady Memorial Hospital	Retrospective cohort	Exposed: all roommates of pts w/Cryptosporidium stool sample and no prior history; unexposed: roommates of pts w/o Cryptosporidium matched by nearest CD4 count and hospitalization date	74 pts (37 exposed, 37 unexposed)	Incident cryptosporidiosis	Roommate w/cryptosporidiosis	Unadjusted RR	RR undefined (one case in unexposed roommates, zero cases in exposed roommates)
Chang and Nelson^Citation42 Score: 94%	March 1987–August 1987	305-bed community hospital, Baltimore, MD	Retrospective cohort	All pts w/LOS >48 h	2,859 pts	Incident Clostridium difficile diarrhea >48 h after admission and within 15 days of discharge	Roommate w/C. difficile diarrhea	Unadjusted RR	RR: 2.7 (0.6–7.0)
Deutscher et al^Citation27 Score: 89%	October 2007–February 2008	57-bed long-term acute care hospital, New Mexico	Case–control	Cases: all pts w/incident GAS infection >48 h after admission; controls: randomly selected pts w/o GAS symptoms or cultures	50 residents (11 cases, 39 controls)	Incident GAS infection >48 h after admission	Roommate w/GAS infection or colonization	Logistic regression adjusted for age, sex, BMI, death, admission to special care unit, LOS >4 weeks, admission from home, C. difficile, diabetes, CHF, hypertension, PVD, chronic renal failure/dialysis, malignancy, ventilator, cellulitis, nonsurgical wound, neg pressure	OR: 15.3 (2.5–110.9)
Drinka et al^Citation28 Score: 72%	1993–2000	Wisconsin Veterans Home, a 635-bed skilled nursing facility	Retrospective cohort	All residents	3,294 resident- seasons	Culture confirmed influenza A infection	Roommate w/pos influenza A culture	Unadjusted RR comparing exposed to pos roommate versus single room	RR: 3.1 (1.6–5.8)
Drinka et al^Citation29 Score: 76%	1992–1993 influenza season	Wisconsin Veterans Home, a 635-bed skilled nursing facility	Retrospective cohort	All residents	489 resident- seasons	Culture confirmed influenza B infection	Roommate w/pos influenza B culture	Unadjusted RR comparing exposed to pos roommate versus single room	RR: 2.6 (1.2–5.6)
Forns et al^Citation30 Score: 80%	August 2000–October 2002	Three-ward liver unit in tertiary care center	Prospective cohort	All pts w/neg anti-HCV screen upon ward admission	1,301 pts	Incident HCV infection assessed 6 months postdischarge	Roommate w/HCV infection	Unadjusted OR	OR: 12.0 (1.4–103.0)
Furuno et al^Citation31 Score: 95%	March 2005–September 2008	120-bed Baltimore Rehabilitation and Extended Care Center, 150-bed Perry Point VA Medical Center, 180-bed University Specialty Hospital, Maryland	Prospective cohort	All residents w/o history of MRSA colonization, ≥1 neg MRSA screen from anterior nares or skin breakdown at enrollment, LOS >7 days, and ≥1 follow-up culture	Residential care: 286; rehabilitation care:157 residents	Incident MRSA colonization in anterior nares or site of skin breakdown	Roommate w/MRSA colonization	Residential care: Cox proportional hazard adjusted for antibiotic therapy and bedbound status; rehabilitation care: Cox proportional hazard HR adjusted for bedbound status and limited mobility status	Residential care HR: 1.4 (0.5–3.9); rehabilitation care HR: 0.5 (0.1–2.2)
Greene et al^Citation32 Score: 78%	January 2001–December 2001	120-bed long-term care facility, Georgia	Retrospective cohort	All residents	125 residents	GAS infection or colonization	Roommate w/GAS colonization or infection	Unadjusted and Mantel–Haenszel RR (variables included in multivariable not described)	Adjusted RR: 2.0 (1.1–5.1); unadjusted RR: 2.1 (1.1–4.0)
Pegues et al^Citation33 Score: 72%	August 1989–September 1989	St Christopher’s Hospital for Children, a 350-bed pediatric referral center, Philadelphia, PA	Case–control	Cases: CF pts w/initial isolation of Pseudomonas cepacia from respiratory secretions; controls: randomly selected CF pts w/neg P. cepacia sputum cultures	28 pts (14 cases, 14 controls)	Pos P. cepacea culture in pts hospitalized ≥1 time between last neg and first pos culture	Roommate w/pos P. cepacea culture	Unadjusted OR	OR: 12.5 (0.6–607.0)
Shorman and Al-Tawfiq^Citation34 Score: 76%	February 2006–March 2010	Tertiary care referral hospital, Damman, Saudi Arabia	Case–control	Cases: pts w/pos surveillance or clinical VRE cultures; controls: randomly selected pts w/neg clinical or surveillance VRE cultures	90 pts (30 cases, 60 controls)	VRE colonization or infection	Roommate with VRE infection or colonization	Unadjusted OR	OR: 0.04 (0.004–0.4)

Abbreviations: BMI, body mass index; CF, cystic fibrosis; CHF, congestive heart failure; GAS, group A streptococcus; HCV, hepatitis C virus; HIV, human immunodeficiency virus; HR, hazard ratio; LOS, length of stay; MRSA, methicillin-resistant Staphylococcus aureus; neg, negative; OR, odds ratio; pos, positive; P. cepacia, Pseudomonas cepacia; pts, patients; PVD, peripheral vascular disease; RR, relative risk; VRE, vancomycin-resistant enterococci; w/, with; w/o, without.

Figure 3 Findings of studies investigating the association between health care-associated infection or colonization and exposure to infected or colonized prior room occupants.

Notes: Studies reporting significant positive associations are represented in black circles. Studies that did not find statistically significant associations are represented in gray circles. No studies reported a significant negative association. Circles display study authors, setting, investigation of endemic versus epidemic pathogen, and quality score.

Table 3 Summary and quality assessment of studies reporting associations between health care-associated infection and exposure to infected or colonized prior room occupants

Author, quality score	Study period	Setting	Design	Subjects	N	Outcome	Exposure	Analysis	Results
Ajao et al^Citation35 Score: 94%	September 2001–June 2009	Medical and surgical ICUs in University of Maryland Medical Center	Retrospective cohort	All pts ≥18 years w/o ESBL at hospital admission, neg ESBL screen at ICU admission, and ICU stay ≥48 h	9,371 admissions (7,651 unique pts)	Acquisition of ESBL- producing pathogen during ICU stay detected by clinical or surveillance culture	Immediate prior room occupant w/pos clinical or surveillance ESBL culture	Logistic regression adjusted for colonization pressure, renal disease, anti-MRSA, and anti-pseudomonal beta- lactam therapies	Unadjusted OR: 1.9 (1.3–2.7); adjusted OR: 1.4 (0.9–2.1)
Bass et al^Citation41 Score: 83%	March 2010–October 2010	34-bed hematology–oncology ward in 427-bed tertiary care teaching hospital, Melbourne, Australia	Quasi-experimental	All pts w/neg VRE rectal swab upon admission and no known history of VRE	439 pts	Incident VRE colonization detected by rectal surveillance culture	Prior bed occupant w/VRE colonization or infection	Cox proportional hazard adjusted for roommate status and study intervention phase	HR: 0.4 (0.1–1.2)
Chang and Nelson^Citation42 Score: 94%	March 1987–August 1987	305-bed community hospital, Baltimore, MD	Retrospective cohort	All pts w/LOS >48 h	2,859 pts	Incident C. difficile diarrhea >48 h after admission and within 15 days of discharge	Prior room occupant with C. difficile or roommate with prior C. difficile infection who is no longer symptomatic	Unadjusted RR	RR: 1.2 (0.3–3.4)
Datta et al^Citation36 Score: 78%	September 2003–April 2005 and September 2006–April 2008	ICUs in 750-bed academic medical center	Quasi-experimental	All pts w/neg MRSA and/or VRE screening culture prior to ICU admission	MRSA: 16,345 pts (7,629 baseline, 8,716 intervention); VRE: 16,630 pts (7,806 baseline, 8,824 intervention)	Incident MRSA or VRE acquisition	Prior room occupant	GLM adjusted for age, sex, pre-ICU LOS, prior occupant LOS, duration of room vacancy, clustering by ward, diabetes, end-stage renal and liver diseases, malignancies, immunocompromised status	MRSA: baseline OR: 1.4 (p=0.04), intervention OR: 1.1 (p=0.66); VRE: baseline OR: 1.4 (p=0.02), intervention OR: 1.4 (p=0.04)
Drees et al^Citation37 Score: 94%	February 2002–March 2003	Medical and surgical ICUs, Tufts-New England Medical Center, Boston, MA	Prospective interventional crossover	All pts in ICU ≥48 h w/neg VRE screens within first 48 h of ICU admission and no known history of VRE	638 pts	Acquisition of VRE during ICU stay detected by surveillance culture	Prior room occupant (immediate and within previous 2 weeks)	HR adjusting for average colonization pressure and mean antibiotics per day	Immediate prior occupant HR: 3.8 (2.0–7.4); prior occupant within 2 weeks HR: 2.7 (1.4–5.3)
Huang et al^Citation38 Score: 94%	September 2003–April 2005	Eight adult ICUs, Brigham and Women’s Hospital, Boston, MA	Retrospective cohort	All pts w/o pos MRSA or VRE surveillance cultures within 2 days of ICU admission	MRSA: 7,629 pts; VRE: 7,806 pts	Acquisition of MRSA or VRE	Prior room occupant with MRSA or VRE colonization or infection	GLM accounting for clustering within ICUs and controlling for age, sex, LOS before ICU admission, prior occupant LOS, duration of room vacancy before occupancy, diabetes, end-stage renal and liver diseases, noncancer immunocompromised state, and malignancies	MRSA OR:1.4 (1.0–1.8); VRE OR: 1.4 (1.0–1.9)
Nseir et al^Citation39 Score: 89%	December 2006–December 2007	30-bed medical/surgical ICU	Prospective cohort	All pts in ICU >48 h w/neg MDR GNB screen at admission	511 pts	Acquisition of Pseudomonas aeruginosa resistant to ceftazidime or imipenem, Acinetobacter baumannii, or ESBL-producing GNB	Prior room occupant w/pos MDR GNB screening or diagnostic culture	Logistic regression: MDR P. aeruginosa model adjusted for age, SAPS II, LOD, transfer from other wards, LOS prior to ICU admission, prior antibiotics, room occupancy rate, central venous, arterial, and urinary catheters, tracheostomy, sedation, percentage of days in the ICU with amoxicillin–clavulanate acid, piperacillin–tazobactam, fourth-generation cephalosporins, carbapenems, fluoroquinolones, aminoglycosides, mechanical ventilation, and LOS in ICU; A. baumannii model adjusted for SAPS II, LOD, admission type, prior antibiotics, colonization pressure, central venous, arterial and, urinary catheters, sedation, percentage of days in ICU with piperacillin–tazobactam, fourth-generation cephalosporins, and fluoroquinolones	MDR P. aeruginosa OR: 2.3 (1.2–4.3); A. baumannii OR: 4.2 (2.0–8.8); ESBL-producing GNB OR: 1.5 (0.6–3.5)(br)Note: multivariable results not reported
Shaughnessy et al^Citation40 Score: 94%	January 2005–June 2006	20-bed ICU in 809-bed tertiary care hospital	Retrospective cohort	All pts w/o Clostridium difficile diagnosis in previous 3 months	1,770 pts	Incident C. difficile infection >48 h after ICU admission and within 30 days of ICU discharge	Immediate prior room occupant w/history of pos C. difficile toxin results within 30 days prior to current occupant’s ICU admission	Adjusted HR controlling for age, APACHE II, proton pump inhibitor, and exposure to antibiotics	HR: 2.4 (1.2–4.5)

Abbreviations: APACHE II, acute physiology and chronic health evaluation II; ESBL, extended-spectrum beta-lactamase–producing organism; GLM, generalized linear mixed model; GNB, Gram-negative bacteria; HR, hazard ratio; ICU, intensive care unit; LOD, logistic organ dysfunction score; LOS, length of stay; MDR, multidrug resistant; MRSA, methicillin-resistant Staphylococcus aureus; neg, negative; OR, odds ratio; pts, patients; pos, positive; RR, relative risk; SAPS II, simplified acute physiology score II; VRE, vancomycin-resistant enterococci; w/, with; w/o, without.

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