Colistin is considered to be an antimicrobial of last-resort for the treatment of multidrug-resistant Gram-negative bacterial infections. The recent global dissemination of mobilized colistin resistance (mcr) genes is an urgent public health threat. An accurate estimate of the global prevalence of mcr genes, their reservoirs and the potential pathways for human transmission are required to implement control and prevention strategies, yet such data are lacking. Publications from four English (PubMed, Scopus, the Cochrane Database of Systematic Reviews and Web of Science) and two Chinese (CNKI and WANFANG) databases published between 18 November 2015 and 30 December 2018 were identified. In this systematic review and meta-analysis, the prevalence of mcr genes in bacteria isolated from humans, animals, the environment and food products were investigated. A total of 974 publications were identified. 202 observational studies were included in the systematic review and 71 in the meta-analysis. mcr genes were reported from 47 countries across six continents and the overall average prevalence was 4.7% (0.1–9.3%). China reported the highest number of mcr-positive strains. Pathogenic Escherichia coli (54%), isolated from animals (52%) and harboring an IncI2 plasmid (34%) were the bacteria with highest prevalence of mcr genes. The estimated prevalence of mcr-1 pathogenic E. coli was higher in food-animals than in humans and food products, which suggests a role for foodborne transmission. This study provides a comprehensive assessment of prevalence of the mcr gene by source, organism, genotype and type of plasmid.

This study aimed to examine the global burden, risk factors, and trends of esophageal cancer based on age, sex, and histological subtype. The data were retrieved from cancer registries database from 48 countries in the period 1980–2017. Temporal patterns of incidence and mortality were evaluated by average annual percent change (AAPC) using joinpoint regression. Associations with risk factors were examined by linear regression. The highest incidence of esophageal cancer was observed in Eastern Asia. The highest incidence of adenocarcinoma (AC) was found in the Netherlands, the United Kingdom, and Ireland. A higher AC/squamous cell carcinoma (SCC) incidence ratio was associated with a higher prevalence of obesity and elevated cholesterol. We observed an incidence increase (including AC and SCC) in some countries, with the Czech Republic (female: AAPC 4.66), Spain (female: 3.41), Norway (male: 3.10), Japan (female: 2.18), Thailand (male: 2.17), the Netherlands (male: 2.11; female: 1.88), and Canada (male: 1.51) showing the most significant increase. Countries with increasing mortality included Thailand (male: 5.24), Austria (female: 3.67), Latvia (male: 2.33), and Portugal (male: 1.12). Although the incidence of esophageal cancer showed an overall decreasing trend, an increasing trend was observed in some countries with high AC/SCC incidence ratios. More preventive measures are needed for these countries.

Tobacco smoking strongly increases risk of esophageal squamous cell carcinoma and moderately increases risk of esophageal adenocarcinoma. How smoking cessation influences esophageal cancer risk across histological subtypes, time latencies, and geographic regions is not clear. Studies were systematically searched on Medline, Embase, Web of Science, Cochrane Library, and ClinicalTrials.gov. Pooled estimates of risk ratios (RRs) were derived using a random effects model. Cochran’s Q test and I² statistic were used to detect heterogeneity. Among 15 009 studies, 52 fulfilled the inclusion criteria. Using nonsmokers as a reference, risk of esophageal squamous cell carcinoma was lower among former smokers (RR = 2.05, 95% confidence interval [CI] = 1.71 to 2.45) than among current smokers (RR = 4.18, 95% CI = 3.42 to 5.12). Compared with current smokers, a strong risk reduction was evident after five or more years (RR = 0.59, 95% CI = 0.47 to 0.75), and became stronger after 10 or more years (RR = 0.42, 95% CI = 0.34 to 0.51) and 20 or more years (RR = 0.34, 95% CI = 0.25 to 0.47) following smoking cessation. The risk reduction was strong in Western populations, while weak in Asian populations. Using nonsmokers as reference, the risk of esophageal adenocarcinoma was only slightly lower among former smokers (RR = 1.66, 95% CI = 1.48 to 1.85) than among current smokers (RR = 2.34, 95% CI = 2.04 to 2.69). The risk of esophageal adenocarcinoma did not show any clear reduction over time after smoking cessation, with a risk ratio of 0.72 (95% CI = 0.52 to 1.01) 20 or more years after smoking cessation, compared with current smokers. Smoking cessation time-dependently decreases risk of esophageal squamous cell carcinoma, particularly in Western populations, while it has limited influence on the risk of esophageal adenocarcinoma.