This systematic review and meta-analysis protocol are reported according to the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (PRISMA-P) checklist provided as an additional file [14].
Eligibility criteria
Type of studies to be included
This review will be included cross-sectional studies, case-control studies (nested or not), and cohort studies (either prospective, retrospective, or ambi-directional) conducted in intensive care units (ICUs). For the meta-analysis, only articles in which risk factors of MDR Pseudomonas aeruginosa acquisition/infection could be assessed will be selected. Studies without data on MDR-PA will be excluded. For multi-disease studies, when MDR-PA data will be not available separately in isolation, these studies will be excluded.
Type of participants
Studies include all patients, admitted to an ICU, whatever the reason for admission and the origin (community, another hospital, or another unit of the same hospital) of patients. No specific definition of ICU will be applied, and all studies which authors reported as having been conducted in an ICU will be considered. We will also include studies where it will possible to identify patients with specimens collected and tested for P. aeruginosa (positivity and antimicrobial susceptibility) during hospitalization and/or samples collected from the ICU patient’s environment (including staff hands and gloves) for P. aeruginosa testing. No specific restrictions on the type of patients will be applied.
Outcomes
The primary outcome
Factors of acquisition of MDR-PA. Since the year 2000, the most common definition of MDR used for gram-positive and gram-negative bacteria is ‘resistant to three or more antimicrobial classes [15].
Secondary outcomes
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(i)
Risk factors of carriage. The carriage was defined as positive screened specimens. These specimens could be collected from rectal swabs, nasal swabs or tracheal aspiration, or others [16].
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(ii)
Risk factors of colonization. Colonization was defined as positive clinical specimens and infection as positive clinical specimens with clinical signs confirming infection.
Search strategy
Six databases will be searched from inception onward, namely MEDLINE (Pubmed), EMBASE (OVID), the Cochrane Library (Wiley), Web of Science, CINAHL (EBSCOHost), and LILACS (BIREME). We will also search in grey literature through.
A search strategy using medical subject headings (MeSH) and text words related to Pseudomonas aeruginosa, intensive care units, carriage, colonization, or infection will be used (Table 1). For studies that will not be found via an internet search, the authors will be directly contacted to obtain them. Also, when a full text will be not available online, the author will be asked by email or telephone to provide it.
Study selection
The search will be conducted by an experienced information specialist, with no language restrictions. For studies published in a language other than English, Deepl translate will be used for translation. The result of electronic searches will be uploaded to Rayyan software for duplicate identification and removal. After this phase, two reviewers will independently screen titles and abstracts of all studies yielded by the search strategy. Firstly, they will screen the studies according to the inclusion and exclusion eligibility criteria. Then, the full text of these selected studies will be retrieved for a second analysis to decide whether the study should be finally included or not. Disagreements between the two reviewers will be resolved through discussion and consensus. PRISMA-P flow diagram template will be used to describe the number of articles retrieved and screened at each step [14].
Data extraction
An online google form will be used to extract data from each included study by two independent reviewers. The following data will be extracted from each report:
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Study characteristics: first author name, year of publication, number of recruitment centers, study design, and sampling method.
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Participants: number of participants, region (s) and country/countries from which participants were recruited, study eligibility criteria, reasons for admission in ICU, age, gender, and duration of hospitalization.
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P. aeruginosa carriage, colonization, or infection data: number of persons who acquired MDR-PA, number of persons who already had MDR-PA, antibiotic tested, number and type of environmental specimens.
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Factors associated with resistant P. aeruginosa: all factors reported in studies will be collected in “authors’ own words” and with their corresponding effect estimates (odds ratios, relative risk, or hazard ratios).
Data synthesis and management
Firstly, a descriptive analysis will be performed on the characteristics of studies, persons included, and risk factors obtained. Secondly, prevalence, odds ratio, relative risk, and hazard ratio with their 95% confidence intervals will be calculated from the compiled data. Thirdly, a meta-analysis of case-control and cohort studies with a similar population, same parameters, and P. aeruginosa testing will be performed. The analysis will evaluate factors influencing the estimates. An analysis by a sub-group of endogenous factors and by subtypes of exogenous factors will be performed. A random effect model will be used to summarize effect sizes. Heterogeneity between combined studies will be tested using the standard Chi-square test with the Q statistic (p <0.10 statistically significant). The extent of heterogeneity will be quantified using the I2 statistics; I2>50% will be deemed as representing substantial inconsistency or significant statistical heterogeneity. Where statistical pooling will be not possible, results will be presented in a synthetic narrative form. All the analyses will be carried out using Stata version 15 (StataCorp, College Station, TX).
Quality of studies and evidence assessment
The methodological quality of studies will be assessed using the National Heart, Lung, and Blood Institute critical appraisal tools for each corresponding study design (cross-sectional, case-control, cohort). Potential bias in the design, conduct, and analysis of each study will be appraised by two independent reviewers. The confidence in evidence will be discussed among the authors.