Review for 10.1186/s12876-025-03634-3 (2025)

Title: Prevalence of Common Diarrheagenic Enterobacteriaceae in Iran (2000-2023): A
Systematic Review and Meta-Analysis
Version: 2 Date: 29 Jul 2024
Reviewer's report:
Abstract:
1. Title:
o The phrase "Systematic and Meta-Analysis Review" is redundant. "Systematic Review and
Meta-Analysis" is the standard phrasing.
o Consider revising to: "Exploring the Incidence of Bacterial Gastroenteritis across Iran: A
Systematic Review and Meta-Analysis"
2. Objective:
o The phrase "stands out for the severity of its infections" is a bit awkward. Consider rephrasing
to "is known for causing severe infections."
o "The objective of the current study is to assess bacterial gastroenteritis pathogens in Iran" could
be clearer as "This study aims to assess the prevalence of bacterial gastroenteritis pathogens in
Iran."
3. Methods:
o The methodology is clear, but it would be helpful to mention if there were any specific
inclusion or exclusion criteria for selecting the articles.
o Mentioning the version of the Comprehensive Meta-Analysis software used can add clarity.
4. Results:
o The result section is well-explained but could benefit from a more detailed description of the
analysis process and any statistical tests used (mention in methods)
o The use of "Figure 3" implies a visual aid which is not included in the abstract. Consider
removing this reference or ensuring that it aligns with the final publication.
5. Conclusion:
o The conclusion succinctly summarizes the findings but should provide more actionable
recommendations based on the findings.
o Consider elaborating on what "further in-depth analyses" might involve or how they could be
practically implemented.
Language and Grammar:
• Generally well-written with only minor adjustments needed for clarity and conciseness.
• Ensure consistency in the usage of species names (e.g., Shigella spp. should be italicized).
Introduction:
1. Clarity and Conciseness:
o The introduction is generally clear, but some sentences are a bit long and could be broken
down for better readability.
o Example: "Gastroenteritis can be considered acute or chronic, on the basis of the severity of
the symptoms" could be split into two sentences for clarity.
2. Terminology:
o Ensure consistent use of terminology. For instance, use either "acute gastroenteritis" and
"chronic gastroenteritis" throughout, instead of switching between "acute" and "short-term" or
"chronic" and "long-term."
3. Scientific Details:
o The introduction provides a thorough background but could benefit from specifying more
about how bacterial gastroenteritis differs in terms of treatment and prognosis compared to viral
or parasitic causes.
o Including specific examples of how bacterial gastroenteritis can be more severe in certain
cases can strengthen the rationale for focusing on bacterial pathogens.
4. Statistics and References:
o The statistics presented are useful but could be enhanced by specifying the sources more
clearly.
o Ensure that all statistics have corresponding references, and the reference numbers should
directly follow the data they support for better readability (e.g., “Diarrhea is a key symptom and
is defined... [3].”).
5. Flow and Structure:
o The flow could be improved by clearly separating the general information about gastroenteritis
from the specific focus on bacterial gastroenteritis.
o Consider adding subheadings if the journal permits, such as "Background on Gastroenteritis"
and "Focus on Bacterial Gastroenteritis," to improve the structure.
6. Specificity to Iran:
o The introduction should better connect the general information on gastroenteritis to the specific
context of Iran. Adding a sentence or two on why studying this condition in Iran is particularly
important would be beneficial.
o Highlight any known regional variations in bacterial gastroenteritis prevalence or impact that
justify the focus on Iran.
7. Aims and Objectives:
o The aim of the meta-analysis is clearly stated, but the objectives could be more succinctly
listed to enhance clarity.
o Example: “This meta-analysis review aims to investigate the frequency of bacterial
gastroenteritis occurrences in Iran from 2000 to 2023. Specifically, the objectives are to: 1)
Determine the overall prevalence of bacterial gastroenteritis, 2) Identify the specific bacterial
strains responsible, and 3) Track the prevalence over time to inform public health interventions.”
8. Grammar and Style:
o Minor grammatical adjustments are needed. For example, "This meta-analysis review aims to
investigate..." should be "This meta-analysis aims to investigate..."
o Ensure consistent use of scientific names (italicize all genus and species names).
Specific Suggestions:
• Break long sentences into shorter ones for clarity.
• Ensure all data points have corresponding references.
• Strengthen the connection between the general background and the specific focus on Iran.
• Clearly list the study’s objectives.
• Maintain consistent terminology and formatting.
Methods:
1. Search Strategy:
o Clarity and Redundancy: The search strategy includes an extensive list of MeSH terms and
keywords, which is thorough but may be overly complex. Simplifying the search terms without
losing specificity can improve clarity.
o Boolean Operators: Ensure the use of Boolean operators is consistent and logical. The search
string as written is highly complex and may need testing to ensure it retrieves the most relevant
studies.
2. Eligibility Criteria and Study Selection:
o Independent Review: The method of having two authors independently review articles is a
good practice to reduce bias. However, it would be beneficial to specify how disagreements
were resolved (e.g., involving a third reviewer).
o Exclusion Criteria: The criteria are well-defined, but ensure all types of non-original research
(e.g., reviews, commentaries) are clearly excluded. It might be helpful to state explicitly that
only peer-reviewed articles were included.
3. Data Analysis:
o Random Effects Model: The choice of the DerSimonian-Laird random effect method is
appropriate for dealing with heterogeneity across studies. However, it's essential to justify this
choice by discussing the expected heterogeneity.
o Publication Bias: The use of funnel plots and Begg's test for publication bias is appropriate.
However, clarify the interpretation of these tests. For instance, a Begg's test p-value less than
0.05 typically indicates the presence of publication bias, not that results are free from bias.
o Statistical Significance: The statement "Results with a p-value less than 0.05 were considered
indicative of bias" is misleading. Typically, a p-value less than 0.05 indicates statistical
significance, suggesting evidence against the null hypothesis. Rephrase to clarify that tests for
publication bias are interpreted differently.
Specific Statistical Errors and Improvements:
1. Search Strategy:
o The search terms and Boolean operators should be tested for efficiency and specificity.
Consider running pilot searches to refine the strategy.
2. Eligibility Criteria and Study Selection:
o Resolution of Discrepancies: Include a specific procedure for resolving discrepancies between
reviewers, such as involving a third independent reviewer.
o PRISMA Flow Chart: Ensure the PRISMA flow chart is detailed and matches the text
description. It should clearly show the number of records identified, screened, eligible, and
included, with reasons for exclusions at each stage.
3. Data Analysis:
o Heterogeneity: Provide a measure of heterogeneity (e.g., I² statistic) and discuss its impact
on the meta-analysis. If heterogeneity is high, consider conducting subgroup analyses or meta-
regression to explore sources of variation.
o Model Justification: Explicitly justify the use of the DerSimonian-Laird random effects model
by discussing the expected heterogeneity among the studies.
o Publication Bias Tests: Clearly describe the interpretation of funnel plots and Begg's test. For
example, "A p-value less than 0.05 in Begg's test suggests the presence of publication bias."
o Sensitivity Analysis: Consider including sensitivity analyses to test the robustness of the
results. This could involve excluding studies with a high risk of bias or conducting leave-one-
out analyses.
Results:
Numbers and References: The total number of articles included (240) is clearly stated. However,
ensure all references are correctly numbered and cited consistently.
Sensitivity Analysis: Consider including sensitivity analyses to test the robustness of the meta-
analysis results, such as excluding studies with a high risk of bias or conducting leave-one-out
analyses.