Identification of risk profiles for Salmonella prevalence in pig supply chains in South Korea using meta-analysis and a quantitative microbial risk assessment model

Characterization of novel mutations involved in the development of resistance to colistin in Salmonella isolates from retail pork in Shanghai, China

Salmonella is an important foodborne pathogen that poses a significant threat to food safety. This study aims to assess the prevalence, genomic features, and colistin-resistant mechanisms of Salmonella isolates collected from 118 retail pork samples from January 2021 to January 2022 in Shanghai, China. Overall, 46 (39.0 %, 46/118) Salmonella isolates were collected, which were identified as 12 serotypes by genomic analysis, including Salmonella Typhimurium (n = 17) and Salmonella London (n = 6). Antimicrobial resistance profiling revealed that the resistance rate of these isolates to colistin was 13.0 % (6/46), while 60.9 % (28/46) exhibited multidrug-resistant. It was found that there were 51 distinct antimicrobial resistance genes in these 46 isolates, which were predominantly associated with resistance to aminoglycosides, fluoroquinolones, and β-lactams. More importantly, among six colistin-resistant isolates, two isolates (Salmonella Schwarzengrund and Salmonella Indiana) were found to carry the mcr-1 gene. The mechanism of resistance in the remaining four colistin-resistant isolates was further studied, and it was found that there were nine amino acid substitutions in PmrAB. It was demonstrated by site-directed mutagenesis that novel substitutions G53W in PmrA and I83V in PmrB led to colistin resistance in Salmonella (MIC = 2 or 4 μg/mL). Analysis results by real-time quantitative PCR and mass spectrometry indicated that the mutants PmrAG53W and PmrBI83V displayed higher expression levels of the gene pmrE than in the parental strain. This upregulation resulted in an increase in the production of 4-amino-4-deoxy-l-arabinose (L-Ara4N) that modified lipid A, thereby conferring resistance to colistin. These findings demonstrated that there was a high prevalence of MDR Salmonella isolates in retail pork in Shanghai, and the substitution G53W in PmrA and I83V in PmrB were independent factors contributing to the development of resistance to colistin in Salmonella via modification of lipid A with L-Ara4N.

Salmonella Control in Swine: A Thoughtful Discussion of the Pre- and Post-Harvest Control Approaches in Industrialized Countries

Pork is among the major sources of human salmonellosis in developed countries. Since the 1990s, different surveys and cross-sectional studies, both national and international (i.e., the baseline studies performed in the European Union), have revealed and confirmed the widespread non-typhoidal Salmonella serotypes in pigs. A number of countries have implemented control programs with different approaches and degrees of success. The efforts could be implemented either at farms, in post-harvest stages, or both. The current review revises the current state of the art in Salmonella in swine, the control programs ongoing or conducted in the past, and their strengths and failures, with particular attention to the weight of pre- and post-harvest control and the implications that both have for the success of interventions or mitigation after outbreaks. This review provides a novel perspective on Salmonella control in swine, a matter that still includes uncertainties and room for improvement as a question of public health and One Health.

Organophosphorus pesticide contaminants in fruits and vegetables: A meta-analysis

The worldwide demand for organophosphorus pesticides (OPs) in food production has raised concerns about pesticide residues. Meta-analysis, proven effective in assessing contaminants like aflatoxins and organotin compounds, is applied here to comprehensively study OP contamination in fresh fruits and vegetables. Employing Comprehensive Meta-Analysis V3.0 software, we meticulously examined 24 relevant articles encompassing 69,467 data points. Our findings revealed that while the residual concentrations of OPs (such as chlorpyrifos and profenofos) in most fruits and vegetables have typically met international or national safety standards, including Codex Alimentarius Commission, European Union, British, and Chinese standards, there are some instances in which the maximum residue limits have been exceeded, posing safety risks. Therefore, significant efforts are required to maintain residual OP contamination at safe concentrations.

The Relationship between Health Insurance and Pharmaceutical Innovation: An Empirical Study Based on Meta-Analysis

The growing research interest in the relationship between health insurance and pharmaceutical innovation is driven by their significant impact on healthcare optimization and pharmaceutical development. The existing literature, however, lacks consensus on this relationship and provides no evidence of the magnitude of a correlation. In this context, this study employs meta-analysis to explore the extent to which health insurance affects pharmaceutical innovation. It analyzes 202 observations from 14 independent research samples, using the regression coefficient of health insurance on pharmaceutical innovation as the effect size. The results reveal that there is a strong positive correlation between health insurance and pharmaceutical innovation (r = 0.367, 95% CI = [0.294, 0.436]). Public health insurance exhibits a stronger promoting effect on pharmaceutical innovation than commercial health insurance. The relationship between health insurance and pharmaceutical innovation is moderated by the country of sample origin, data range, journal type, journal impact factor, type of health insurance, and research perspective. Our research findings further elucidate the relationship mechanism between health insurance and pharmaceutical innovation, providing a valuable reference for future explorations in pharmaceutical fields.