Effect of veterinary feed directive rule changes on tetracycline-resistant and erythromycin-resistant bacteria (Salmonella, Escherichia, and Campylobacter) in retail meats in the United States

Effect of orally administered B. subtilis-cNK-2 on growth performance, immunity, gut health, and gut microbiome in chickens infected with Eimeria acervulina and its potential as an alternative to antibiotics

This study investigated the best oral delivery strategy (gavage or feed) for the B. subtilis expressing the chicken anti-microbial peptide cNK-2 (B. subtilis-cNK-2) in comparison to monensin, in chickens challenged with Eimeria acervulina (E. acervulina). A total of 120 broiler chickens were randomly allocated into 5 treatment groups in a completely randomized design: 1) uninfected chickens fed with basal diet (NC), 2) E. acervulina-infected chickens fed a basal diet (PC), 3) E. acervulina-infected chickens fed a basal diet supplemented with 90 mg monensin/kg feed (MO), 4) E. acervulina-infected chickens fed a basal diet and orally gavaged with B. subtilis-cNK-2 at 1 × 1010 cfu/d (CNK-O), and 5) E. acervulina-infected chickens fed a basal diet mixed with B. subtilis-cNK-2 at 1 × 1010 cfu/kg feed (CNK-F). The challenge consisted of 5,000 sporulated E. acervulina oocysts through oral gavage on d 15. Body weights were measured on d 7, 14, 21, and 23. Duodenal tissue and digesta samples were collected at 6 d postinfection (dpi) to assess the gut integrity, oxidative stress, mucosal immunity, and the gut microbiome. Fecal samples were collected from 6 to 8 dpi to enumerate the oocyst shedding. Chickens in the CNK-O group showed improved (P < 0.05) growth performance, gut integrity, and mucosal immunity compared to PC, comparable to chickens in the MO group. Chickens in the MO, CNK-F, and CNK-O treatment groups all showed lower (P < 0.05) oocyst shedding compared to PC chickens. Moreover, distinct cytokine profile, oxidative stress measures, tight junction proteins, and shifts in the gut microbiome with associated functional changes were observed in all challenge groups. In conclusion, we showed that the oral administration of B. subtilis-cNK-2 improved growth performance, enhanced local protective immunity, and reduced fecal oocyst shedding in broiler chickens infected with E. acervulina, demonstrating potential use of B. subtilis-cNK-2 as an alternative to antibiotics to protect chickens against coccidiosis.

Salmonella spp. in Domestic Ruminants, Evaluation of Antimicrobial Resistance Based on the One Health Approach-A Systematic Review and Meta-Analysis

Salmonella spp. pose a global threat as a leading cause of foodborne illnesses, particularly prevalent in the European Union (EU), where it remains the second cause of foodborne outbreaks. The emergence of antimicrobial resistance (AMR) in Salmonella spp. has become a critical concern, complicating treatment strategies and escalating the risk of severe infections. The study focuses on large and small ruminants, identifying a prevalence of Salmonella spp. in slaughterhouses and revealing varied AMR rates across antimicrobial families throughout a meta-analysis. Also, comparison with AMR in human medicine was carried out by a systematic review. The results of the present meta-analysis displayed a prevalence of Salmonella spp. in large and small ruminants at slaughterhouses of 8.01% (8.31%, cattle; 7.04%, goats; 6.12%, sheep). According to the AMR of Salmonella spp., 20, 14, and 13 out of 62 antimicrobials studied were classified as low (<5%), high (>5% but <10%), and very high (>10%), respectively. Salmonella spp. did not display AMR against aztreonam, mezlocillin, ertapenem, meropenem, cefoxitin, ceftazidime, levofloxacin, tilmicosin, linezolid, fosfomycin, furazolidone, quinupristin, trimethoprim and spectinomycin. In contrast, a prevalence of 100% of AMR has been described against ofloxacin, lincomycin, and cloxacillin. In the context of the main antibiotics used in the treatment of human salmonellosis, azithromycin was shown to have the highest resistance among Salmonella spp. isolates from humans. Regarding cephalosporins, which are also used for the treatment of salmonellosis in humans, the prevalence of Salmonella spp. resistance to this class of antibiotics was similar in both human and animal samples. Concerning quinolones, despite a heightened resistance profile in Salmonella spp. isolates from ruminant samples, there appears to be no discernible compromise to the efficacy of salmonellosis treatment in humans since lower prevalences of AMR in Salmonella spp. isolated from human specimens were observed. Although the resistance of Salmonella spp. indicates some degree of concern, most antibiotics are not used in veterinary medicine. Thus, the contribution of cattle, sheep and goats to the rise of antibiotic resistance of Salmonella spp. and its potential impact on public health appears to be relatively insignificant, due to their low prevalence in carcasses and organs. Nevertheless, the observed low prevalence of Salmonella spp. in ruminants at slaughterhouse and the correspondingly low AMR rates of Salmonella spp. to key antibiotics employed in human medicine do not indicate that ruminant livestock poses a substantial public health risk concerning the transmission of AMR. Thus, the results observed in both the meta-analysis and systematic review suggests that AMR is not solely attributed to veterinary antibiotic use but is also influenced by factors such as animal health management (i.e., biosecurity measures, prophylactic schemes) and human medicine.

Prevalence, serotype, antimicrobial susceptibility, contamination factors, and control methods of Salmonella spp. in retail fresh fruits and vegetables: A systematic review and meta-analysis

This research presents a comprehensive review of Salmonella presence in retail fresh fruits and vegetables from 2010 to 2023, utilizing data from recognized sources such as PubMed, Scopus, and Web of Science. The study incorporates a meta-analysis of prevalence, serovar distribution, antimicrobial susceptibility, and antimicrobial resistance genes (ARGs). Additionally, it scrutinizes the heterogeneous sources across various food categories and geographical regions The findings show a pooled prevalence of 2.90% (95% CI: 0.0180-0.0430), with an increase from 4.63% in 2010 to 5.32% in 2022. Dominant serovars include S. Typhimurium (29.14%, 95% CI: 0.0202-0.6571) and S. Enteritidis (21.06%, 95% CI: 0.0181-0.4872). High resistance rates were noted for antimicrobials like erythromycin (60.70%, 95% CI: 0.0000-1.0000) and amoxicillin (39.92%, 95% CI: 0.0589-0.8020). The most prevalent ARGs were blaTEM (80.23%, 95% CI: 0.5736-0.9692) and parC mutation (66.67%, 95% CI: 0.3213-0.9429). Factors such as pH, water activity, and nutrient content, along with external factors like the quality of irrigation water and prevailing climatic conditions, have significant implications on Salmonella contamination. Nonthermal sterilization technologies, encompassing chlorine dioxide, ozone, and ultraviolet light, are emphasized as efficacious measures to control Salmonella. This review stresses the imperative need to bolster prevention strategies and control measures against Salmonella in retail fresh fruits and vegetables to alleviate related food safety risks.

Contaminants of Emerging Concern: Antibiotics Research in Mussels from the Coasts of the Tyrrhenian Sea (Sardinia, Italy)

Contaminants of emerging concern (CECs) are compounds found in several environmental compartments whose ubiquitous presence can cause toxicity for the entire ecosystem. Several personal care products, including antibiotics, have entered this group of compounds, constituting a major global threat. It is essential to develop simple and reliable methods by which to quantify these contaminants in several matrices. In this work, mussels were chosen as sentinel organisms to assess environmental pollution and the safety of bivalve mollusk consumption according to the "One Health perspective". A liquid chromatographic tandem mass spectrometry method (LC-MS/MS) was developed for the quantification of two macrolides, erythromycin (ERY) and azithromycin (AZI), in mussels. This new method was validated according to international guidelines, showing high selectivity, good recoveries (>60% for both of them), sensitivity, and precision. The method was successfully applied for ERY and AZI research in mussels farmed along the Sardinian coasts (Italy), demonstrating itself to be useful for routine analysis by competent authorities. The tested macrolides were not determined in the analyzed sites at concentrations above the limits of detection (LODs). These results demonstrate the food safety of mussels (as concerns the studied antibiotics) and a negligible amount of pollution derived from these drugs in the studied area.

Monitoring antimicrobial resistance in Campylobacter isolates of chickens and turkeys at the slaughter establishment level across the United States, 2013-2021

Foodborne infections with antimicrobial-resistant Campylobacter spp. remain an important public health concern. Publicly available data collected by the National Antimicrobial Resistance Monitoring System for Enteric Bacteria related to antimicrobial resistance (AMR) in Campylobacter spp. isolated from broiler chickens and turkeys at the slaughterhouse level across the United States between 2013 and 2021 were analysed. A total of 1,899 chicken-origin (1,031 Campylobacter coli (C. coli) and 868 Campylobacter jejuni (C. jejuni)) and 798 turkey-origin (673 C. coli and 123 C. jejuni) isolates were assessed. Chicken isolates exhibited high resistance to tetracycline (43.65%), moderate resistance to ciprofloxacin (19.5%), and low resistance to clindamycin (4.32%) and azithromycin (3.84%). Turkey isolates exhibited very high resistance to tetracycline (69%) and high resistance to ciprofloxacin (39%). The probability of resistance to all tested antimicrobials, except for tetracycline, significantly decreased during the latter part of the study period. Turkey-origin Campylobacter isolates had higher odds of resistance to all antimicrobials than isolates from chickens. Compared to C. jejuni isolates, C. coli isolates had higher odds of resistance to all antimicrobials, except for ciprofloxacin. The study findings emphasize the need for poultry-type-specific strategies to address differences in AMR among Campylobacter isolates.