Overview of pathogenic Escherichia coli, with a focus on Shiga toxin-producing serotypes, global outbreaks (1982-2024) and food safety criteria.

Classification of pathogenic E. coli has been focused either in mammalian host or infection site, which offers limited resolution. This review presents a comprehensive framework for classifying all E. coli branches within a single, unifying figure. This approach integrates established methods based on virulence factors, serotypes and clinical syndromes, offering a more nuanced and informative perspective on E. coli pathogenicity. The presence of the LEE island in pathogenic E. coli is a key genetic marker differentiating EHEC from STEC strains. The coexistence of stx and eae genes within the bacterial genome is a primary characteristic used to distinguish STEC from other pathogenic E. coli strains. The presence of the inv plasmid, Afa/Dr adhesins, CFA-CS-LT-ST and EAST1 are key distinguishing features for identifying pathogenic E. coli strains belonging to EIEC, DAEC, ETEC and EAEC pathotypes respectively. Food microbiological criteria differentiate pathogenic E. coli in food matrices. 'Zero-tolerance' applies to most ready-to-eat (RTE) foods due to high illness risk. Non-RTE foods' roles may allow limited E. coli presence, which expose consumers to potential risk; particularly from the concerning Shiga toxin-producing E. coli (STEC) strains, which can lead to life-threatening complications in humans, including haemolytic uremic syndrome (HUS) and even death in susceptible individuals. These findings suggest that decision-makers should consider incorporating the separate detection of STEC serotypes into food microbiological criteria, in addition to existing enumeration methods. Contamination of STEC is mainly linked to food consumption, therefore, outbreaks of E. coli STEC has been reviewed here and showed a link also to water as a potential contamination route. Since their discovery in 1982, over 39,787 STEC cases associated with 1,343 outbreaks have been documented. The majority of these outbreaks occurred in the Americas, followed by Europe, Asia and Africa. The most common serotypes identified among the outbreaks were O157, the 'Big Six' (O26, O45, O103, O111, O121, and O145), and other serotypes such as O55, O80, O101, O104, O116, O165, O174 and O183. This review provides valuable insights into the most prevalent serotypes implicated in STEC outbreaks and identifies gaps in microbiological criteria, particularly for E. coli non-O157 and non-Big Six serotypes.

Evaluating the effectiveness of the Ministry of Health restriction policy on seasonal antibiotic consumption trends in Saudi Arabia, 2016-2020.

Background: Understanding antibiotic consumption patterns over time is essential to optimize prescribing practices and minimizing antimicrobial resistance. This study aimed to determine whether the antibiotics restriction policy launched by the Saudi Ministry of Health in April 2018 has impacted antibiotic use by assessing changes and seasonal variations following policy enforcement. Methods: Quarterly sales data of J01 antibacterial for systemic use in standard units were obtained from the IQVIA-MIDAS database, spanning from the first quarter of 2016 to the last quarter of 2020. Antibiotics consumption was measured in defined daily doses per 1,000 inhabitant per day- in a quarter (DDDdq). A comparative analysis of antibiotic consumption pre- and post-policy periods introduction was conducted by computing the average consumption values for each period. Statistical comparison of the mean differences between the two periods were then made using independent samples t-test, Mann-Whitney U Test where needed. Time series analysis was employed to estimate the projected antibiotic consumption in the post-policy period if the restriction policy had not been implemented, which was then compared to actual consumption values to evaluate the effectiveness of the restriction policy. Results: During the pre-policy, there were seasonal trends of the total and oral antibiotic consumption through quarters, with higher consumption observed in the first and fourth quarters. In contrast, parenteral antibiotic consumption did not appear to follow a clear seasonal pattern. Following the restriction policy, there was a significant reduction in total and oral antibiotic use, with mean reductions of -96.9 DDDdq (p-value = 0.002) and -98 DDDdq (p-value = 0.002), respectively. Conversely, a significant increase in parenteral antibiotic consumption was observed with a mean increase of +1.4 DDDdq (p-value < 0.0001). The comparison between the forecasted and actual models showed that the actual antibiotics consumption for total, oral, and parenteral were lower than the corresponding forecasted values by 30%, 31%, and 34%, respectively. Conclusion: Overall, our analysis of antibiotics consumption from 2016 to 2020 displays great success for the policy implemented by the Saudi Ministry of Health in significantly reducing the total and oral use of antibiotics. However, future studies are needed to explore the increased consumption of the parenteral antibiotics as well as the persistent high consumption patterns during the fall and winter months even after the implementation of the restriction policy.

The Silent Threat: Antimicrobial-Resistant Pathogens in Food-Producing Animals and Their Impact on Public Health.

The emergence of antimicrobial resistance (AMR) is a global health problem without geographic boundaries. This increases the risk of complications and, thus, makes it harder to treat infections, which can result in higher healthcare costs and a greater number of deaths. Antimicrobials are often used to treat infections from pathogens in food-producing animals, making them a potential source of AMR. Overuse and misuse of these drugs in animal agriculture can lead to the development of AMR bacteria, which can then be transmitted to humans through contaminated food or direct contact. It is therefore essential to take multifaceted, comprehensive, and integrated measures, following the One Health approach. To address this issue, many countries have implemented regulations to limit antimicrobial use. To our knowledge, there are previous studies based on AMR in food-producing animals; however, this paper adds novelty related to the AMR pathogens in livestock, as we include the recent publications of this field worldwide. In this work, we aim to describe the most critical and high-risk AMR pathogens among food-producing animals, as a worldwide health problem. We also focus on the dissemination of AMR genes in livestock, as well as its consequences in animals and humans, and future strategies to tackle this threat.

Antimicrobial resistance and genomic characterization of Salmonella enterica isolates from chicken meat.

This study investigated genotypic and phenotypic antimicrobial resistance profiles, phylogenic relatedness, plasmid and virulence composition of 39 Salmonella enterica strains isolated from chicken meat samples using whole genome sequencing (WGS) technology. Four distinct serotypes were identified; Salmonella Minnesota (16/39, 41%), Salmonella Infantis (13/39, 33.3%), Salmonella Enteritidis (9/39, 23.1%), and one isolate was detected for Salmonella Kentucky (1/39, 2.6%), with sequence types (STs) as followed: ST548, ST32, ST11, and ST198, respectively. Phenotypic resistance to tetracycline (91.2%), ampicillin (82.4%), sulfisoxazole (64.7%), and nalidixic acid (61.6%) was the most observed. Resistome analysis revealed the presence of resistance genes to aminoglycosides, ß-lactamase, sulfonamides, trimethoprim, phenicol, lincosamide, macrolides, and tetracyclines. Plasmidome showed the presence of eight incompatibility groups, including IncA/C2, IncFIB(K)_1_Kpn3, Col440I_1, IncR, IncX1, IncI1_1_Alpha, IncFIB(S)/IncFII(S), IncHI2/IncHI2A, IncX2 and ColpVC plasmids across the 39 genomes. Three resistance genes, sul2, tetA and blaCMY-2, were predicted to be located on IncA/C2 plasmid in S. Minnesota isolates, whereas all S. Infantis isolates were positive to IncFIB(K)_1_Kpn3 plasmid that carries bla CTX-M-65 gene. Eleven Salmonella pathogenicity islands and up to 131 stress and/or virulence genes were identified in the evaluated genomes. Phylogenetic analysis showed four phylogroups that were consistent with the identified ST profiles with a high level of inter-diversity between isolates. This is the first genomic characterization of Salmonella isolates from retail chicken meat in Saudi Arabia using WGS technology. The availability of Salmonella genomes from multiple geographic locations, including Saudi Arabia, would be highly beneficial in future source-tracking, especially during epidemiological surveillance and outbreak investigations.

Antimicrobial Sales Comparison before and after the Implementation of Nationwide Restriction Policy in Saudi Arabia.

Antimicrobial dispensing without a prescription has been identified as a significant contributor to the burgeoning crisis of antimicrobial resistance. To combat this, the Saudi Ministry of Health introduced a stringent antimicrobial restriction policy in mid-2018, mandating prescriptions for all antimicrobial drug dispensations at pharmacies. Therefore, this study aimed to assess the immediate impact of this policy on retail antimicrobial sales. To do so, we analyzed annual sales data from 2017 to 2019 sourced from the IQVIA-MIDAS® database, which included a range of antimicrobials, such as antibiotics, antifungals, and other related agents. The analysis revealed a notable reduction in overall antimicrobial sales by 23.2%, decreasing from 818.9 million SAR in 2017 to 648.4 million SAR in 2019. While the Wilcoxon signed-rank test indicated a statistically significant median reduction in total antimicrobial sales post-policy implementation (p = 0.0397), it is important to acknowledge that the long-term effects and adherence to the policy require further investigation. Notably, sales of amoxicillin dropped by 70% in 2019 compared to 2017, contributing largely to the decline. Conversely, a continuous increase in sales of some antimicrobial drugs following the restriction policy was observed, led by amoxicillin/clavulanic acid. Our data support the implementation of antimicrobial restriction measures as an effective means of controlling excessive antimicrobial sales and dispensing without prescriptions.

Complete Genome Sequence of a Colistin-Susceptible Salmonella enterica Serovar Minnesota Strain Harboring mcr-9 on an IncHI2/IncHI2A Plasmid, Isolated from Chicken Meat.

The recent emergence and dissemination of mobilized colistin resistance (mcr) genes have triggered extensive concerns globally. Here, we report the complete genome sequence of a colistin-susceptible Salmonella enterica serotype Minnesota strain (named SA18578), belonging to sequence type 548 (ST548) and carrying the mcr-9 gene on an IncHI2/IncHI2A plasmid, that was isolated from chicken meat in Saudi Arabia in 2020.