Animal contact as a source of human non-typhoidal salmonellosis

Ecological prevalence and genomic characterization of Salmonella isolated from selected poultry farms in Jiangxi province, China

Non-typhoidal Salmonella (NTS), particularly antimicrobial-resistant serovars, remains the major source of foodborne bacterial illnesses. Raw chicken is the leading cause of human salmonellosis. In this study, we evaluated the prevalence, antimicrobial resistance profiles, and genomic features of 143/1,800 (7.94%) Salmonella strains isolated from poultry farms in five major regions of Jiangxi province, China, between 2022 and 2023 using Whole genome sequencing (WGS). Among Salmonella isolates, the most common serovars were Infantis (ST32) and Enteritidis (ST11). Resistance to amoxicillin and tetracycline was the most prevalent, with 60.84% of Salmonella isolates exhibiting a multi-drug resistance (MDR) pattern. The detection of antimicrobial-resistant genes (ARGs) examined was aligned with the resistant phenotypes found. A total of 61 ARGs were identified, with aph(3')-Ia, qnrS1, aph(3'')-Ib, and tetA being the prominent ARGs. Furthermore, 24 beta-lactam genes were also identified, including blaTEM, blaSHV, and blaCTX-M. The number of ARGs and the distribution of serovars varied according to the year, farms, and cities. Salmonella isolates carried 13 heavy metal resistance genes (HMRGs) and two biocide resistance genes, with pcoS being the most prevalent. A total of 145 virulence genes and 19 plasmids were found, with serovars Infantis and Enteritidis having the most virulence genes. The high occurrence of MDR Salmonella in this study, particularly carrying numerous mobile genetic elements (MGEs), posed a serious threat to food safety and public health, emphasizing the need to improve poultry farm hygiene to decrease contamination and transmission.

Salmonella enterica serovar Braenderup shows clade-specific source associations and a high proportion of molecular epidemiological clustering

Salmonella enterica serovar Braenderup (S. enterica ser. Braenderup) is an important clinical serovar in the United States. This serovar was reported by the CDC in 2017 as the fifth most common Salmonella enterica serovar associated with outbreaks in the United States, which have been linked to both fresh produce and food animal products. The goals of this study were to compare the relatedness of human clinical isolates from southeastern USA (Tennessee (n = 106), Kentucky (n = 48), Virginia (n = 252), South Carolina (n = 109), Georgia (n = 159), Alabama (n = 8), Arkansas (n = 26), and Louisiana (n = 91)) and global clinical (n = 5,153) and nonclinical (n = 1,053) isolates obtained from the NCBI. Additionally, we also examined the population structure of S. enterica ser. Braenderup strains (n = 3,131) on EnteroBase and found that all the strains of this serovar are associated with a single cgMLST eBurst group (ceBG 185), confirming that this serovar is monophyletic. We divided the S. enterica ser. Braenderup population into two clades (Clade I and Clade II) and one clade group (Clade Group III). The composition of distinct environmental isolates in the clades differed: Clade I was significantly associated with produce (90.7%; P < 0.0001) and water, soil, and sediment (76.9%; P < 0.0001), and Clade II was significantly associated with poultry environments (62.8%; P < 0.0001). The clade-specific gene associations (e.g., Clade I-associated competence proteins and cytochrome_c_asm protein and Clade II-associated heme-exporter protein and dimethyl sulfoxide [DMSO] reductase-encoding genes) provide potential insights into possible mechanisms driving environmental adaptation and host-pathogen interaction. Phylogenetic analyses identified 218 molecular epidemiological clusters in the current study, which represented a greater proportion of potentially outbreak-related isolates than previously estimated.

IMPORTANCE

This study provides insights into the genomic diversity of S. enterica ser. Braenderup by revealing distinct clade-specific source attribution patterns and showing that a greater proportion of isolates were associated with epidemiological clusters based on the genomic relatedness than previously estimated. Specifically, we analyzed the diversity of human clinical isolates from southeastern USA and compared them with the global clinical and nonclinical isolates. Our analysis showed different clades of S. enterica ser. Braenderup linked to different environments, providing insights on the potential source of human sporadic infection and outbreaks. These findings can enhance public health surveillance and response strategies targeting S. enterica serovar Braenderup by expanding our understanding of potential transmission pathways and the genomic diversity of clinical and environmental isolates.

Salmonella isolated from street foods and environment of an urban park: A whole genome sequencing approach

Salmonella is one of the most important foodborne pathogens worldwide. Therefore, this study was conducted to understand the importance of this microorganism in street food and the environment of an urban park in Quito, Ecuador. This research included phenotypic characterization and whole genome sequencing (WGS) analysis of isolates from different food matrices and fecal samples of dogs and pigeons. Salmonella was found in 10% (18/180) of the food samples, 3% (3/100) of the dog stool samples, and 5% (5/100) of the pigeon stool samples. These results also showed that meals containing any sauce or eggs were associated with a high probability of Salmonella isolation, regardless of other ingredients. All Salmonella isolates from food were identified as Salmonella enterica serovar Typhimurium (S. Typhimurium) while isolates from animal feces belonged to Salmonella enterica serovar Infantis (S. Infantis) and S. Typhimurium. WGS analysis showed that all S. Typhimurium strains belonged to ST19 and S. Infantis to ST32 according to the Multi-Locus Sequence Type (MLST) scheme. These strains were not related to Salmonella genomes of other origins when a Single Nucleotide Polymorphism (SNP) tree analysis was carried out. Antimicrobial resistance genes, such as blaCTX-M-65, were predominantly linked to the pESI-like plasmid found in S. Infantis. These results show the importance of urban fauna as a reservoir of S. Infantis and the impact these animals could have in terms of public health.

Serological Distribution of Salmonella enterica subsp. Isolated from Feces of Domesticated Crested Gecko (Correlophus ciliates) in Busan Province, South Korea

Geckos are often considered to be reservoirs of zoonotic pathogens. This study was conducted to describe the prevalence and characteristics of pathogens isolated from fecal samples of crested geckos in South Korea. A total of 76 fecal samples were collected from 76 domesticated crested geckos in independent captivity. To determine bacterial profiles, matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS), the disk diffusion method, PCR and direct sequencing, and the Kauffmann-White scheme for serotyping Salmonella species were performed. A total of 107 Gram-negative isolates were identified as belonging to 50 Citrobacter species, 33 Salmonella enterica subsp., 8 Serratia marcescens, 8 Klebsiella species, 3 Morganella morganii, 2 Enterobacter cloacae, 2 Pseudomonas aeruginosa, and 1 Acinetobacter species. Most of the isolates were susceptible to antibiotics tested in this study. The chloramphenicol acetyltransferase (cat) gene was detected in one M. morganii isolate, and the class C beta-lactamase (AZECL-14) gene was detected in one E. cloacae. The most prevalent somatic (O) antigens of the groups were C (n = 23) and D (n = 7), and 8 different serotypes were identified among the 33 Salmonella enterica subsp. isolates. Five of eight Salmonella serotypes have not been previously reported among clinical isolates in South Korea. Our results reveal that enteric bacteria have not been shared between crested geckos and humans, at least in South Korea.

Reptile trade and chelonians-associated Salmonellosis in humans: A public health concern

Animal trade has become a serious criminal practice in the world. Every day thousands of exotic wild animals, including reptiles, are farmed and sold worldwide. The illegal collection of turtles and tortoises remains completely unsupervised and represents a big challenge for responsible authorities. This has consequences for animals and public health because it can contribute to the spread of multiple zoonotic pathogens by introducing exotic species into new geographical areas like wet markets, pet shops, and houses. Non-typhoidal Salmonella are bacteria that can commonly cause self-limiting gastroenteritis but can also cause more serious symptoms, especially in more vulnerable people with impaired immune systems. There is growing evidence linking Salmonella to reptiles, especially chelonians, and its prevalence has increased recently as turtles and tortoises have become popular as new pets. These animals can potentially transmit antimicrobial resistant strains of Salmonella to humans, which puts people in danger, especially young children. Pet owners should be aware and take all the control measures to prevent the infection. This updated review investigates the reptile trade situations worldwide, including chelonians, explaining their relationship with the spread of Salmonella and the risk of infections for humans.

The effects of rain and drought on incidence of enteric disease in Pennsylvania (2010-2019)

BACKGROUND

Campylobacter, nontyphoidal Salmonella, Cryptosporidium, and Giardia cause an estimated 1 million cases of domestically acquired waterborne diseases annually in the United States. Acute symptoms can include diarrhea and vomiting; however, these illnesses can result in longer term complications such as reactive arthritis, Guillan Barré syndrome and death, particularly in immunocompromised individuals. Precipitation and drought can plausibly increase the risk of enteric infections, but consensus in the literature is lacking.

OBJECTIVES

To determine the effects of rain and drought on weekly counts of reportable enteric illness (due to Salmonella, Campylobacter, Giardia, or Cryptosporidium) in Pennsylvania, US between 2010 and 2019.

METHODS

We obtained 10-years of data on confirmed illness from 66 Pennsylvania counties due to: Salmonella (9,924), Campylobacter (15,854), Giardia (4,537), and Cryptosporidium (4,017). A zero-inflated negative binomial model with random-intercept for county was used to assess the relationship between illnesses caused by these pathogens between 2010 and 2019, and weekly rain (cm) and Palmer Drought Severity Index (PDSI) values from the National Weather Service. The lag times that were tested, between illness and weather event, were chosen by calculating the cross correlation between the statewide average weekly rain and the statewide number of weekly cases.

RESULTS

A positive association was found between rain and counts of campylobacteriosis, salmonellosis, and giardiasis. An increase in prior wetness (PDSI value) was associated with increased incidence rates of cryptosporidiosis and campylobacteriosis. The relationship between rain and PDSI and illness varied by organism type.

DISCUSSION

Complex relationships exist between enteric disease and precipitation and prior environmental wetness. Our findings suggest that rainfall may be contributing to increased waterborne exposure. Further investigation is needed to explore these relationships with factors such as drinking water source, local geological conditions, presence of combined sewer overflows and agricultural activities, recreational water use and irrigation water sources to better elucidate important waterborne transmission pathways.

Exogenous cystine increases susceptibility of drug-resistant Salmonella to gentamicin by promoting oxidation of glutathione metabolism and imbalance of intracellular redox levels

Introduction

Antibiotic overuse has caused the development of bacterial resistance, which is a major threat to public health. Intracellular metabolic processes are essential for maintaining the normal physiological activities of bacteria, and an increasing body of research has demonstrated a significant association between metabolic alterations and the development of drug resistance. Numerous studies have demonstrated that the addition of adjuvants can counteract bacterial antibiotic resistance.

Method

Cystine treatment was verified in vitro to promote the lethal effect of gentamicin on Salmonella using in vitro bactericidal counting methods. The metabolic differences in Salmonella enterica Typhimurium standard strain ATCC 14028 with or without the addition of cystine were analyzed via untargeted metabolomics. The multifunctional electronic enzyme marker was used to determine intracellular reduced glutathione/oxidized glutathione (GSH/GSSG), ferrous iron on (Fe2+), and reactive oxygen species (ROS) levels. The expression of glutathione and stress genes was determined using real-time quantitative PCR.

Result

We confirmed that exogenous cystine increased the lethal effect of gentamicin against strain S. enterica Typhimurium (ATCC 14028) and other clinically resistant Salmonella serotypes. Exogenous cystine stimulated the metabolism of the cell and activated the glutathione pathway while altering the GSH/GSSG ratio, which placed bacteria in a state of redox imbalance with increased Fe2+ and ROS levels. Our results suggest that when bacterial redox levels are reprogrammed, bacterial susceptibility to antibiotics can also change.

Discussion

This study confirms that cystine enhances the antimicrobial efficacy of gentamicin against drug-resistant Salmonella. Through the application of metabolomics, the underlying metabolic mechanisms by which cystine exerts its effects on Salmonella have been elucidated, offering a novel perspective in the domain of metabolic reprogramming aimed at counteracting drug resistance. Furthermore, these findings reinforce the potential role of small-molecule metabolites as effective adjuvants to enhance antibiotic action.

Antimicrobial Resistance and Zoonotic Potential of Nontyphoidal Salmonella From Household Dogs

BACKGROUND

Companion animals, like household dogs, are an overlooked transmission point for zoonotic pathogens such as nontyphoidal Salmonella (NTS). Given the proximity of dogs to humans and the use of critically important antibiotics in companion animal medicine, household dogs represent a risk for the spread of antimicrobial-resistant (AMR) Salmonella.

METHODS AND RESULTS

To this end, we aimed to leverage existing biosurveillance infrastructure to investigate AMR and the zoonotic potential of NTS isolated from dogs and humans. We identified all NTS strains isolated from domestic dogs via the Veterinary Laboratory Investigation and Response Network between May 2017 and March 2023 (N = 87), and spatiotemporally matched strains isolated from humans in the NCBI Pathogen Isolate Browser (N = 77). These 164 strains, collected from 17 states in the United States, formed the basis of our analysis. Strains isolated from dogs comprised diverse serovars, with most being clinically relevant to human health. All strains possessed AMR determinants for drug classes deemed critically or highly important by the World Health Organization. We identified sixteen NTS isolates from humans closely related to ≥1 of six dog-associated strains.

CONCLUSIONS

Collectively, our data emphasize the importance of antimicrobial stewardship and sustained biosurveillance beyond human- and agriculture-associated veterinary medicine, using a One-Health framework that accounts for all transmission points including companion animals.

Evaluation of multi-drug resistance, virulence factors, and antimicrobial resistance genes of non-typhoidal Salmonella isolated from ruminants as a potential human health threat in Razavi Khorasan, northeastern Iran

Non-typhoidal Salmonella (NTS) is a significant foodborne pathogen that poses a threat to human health by causing infections and potentially acquiring antibiotic resistance. We evaluated thirty-five Salmonella serovars previously isolated from cattle, sheep, goats, and their retail meat in Razavi Khorasan Province, Iran. The isolates were confirmed with Salmonella polyvalent antiserum. Furthermore, PCR was used to identify the Salmonella Enteritidis, Salmonella Typhimurium, and the host-adapted serovars Salmonella Dublin and Salmonella Abortusovis. Additionally, the antimicrobial susceptibility of the serovars was evaluated using the disk diffusion method. Subsequently, the occurrence of antimicrobial resistance genes and virulence factors was evaluated using the PCR technique. Molecular typing revealed that 20 % of the isolates were S. Typhimurium, 11.4 % were S. Dublin, 8.6 % were S. Enteritidis, 5.7 % were S. Abortusovis, and 54.3 % (19 isolates) were classified as non-typed serovars. Salmonella isolates showed high susceptibility to ciprofloxacin (91.4 %), colistin (88.6 %), gentamicin (88.6 %), and cefotaxime (85.7 %) while exhibiting high resistance to others such as ampicillin (88.6 %), streptomycin (74.3 %), and tetracycline (51.4 %). The most prevalent resistance genes in non-typhoidal Salmonella (NTS) are blaTEM (91.4 %), sul1 (65.7 %), and aadA (54.3 %). Additionally, twenty-five isolates (71.4 %) showed multi-drug resistance profiles. The most frequent virulence genes are stn (100 %), iroN (100 %), and pefA (42.9 %). The current study has revealed that Salmonella serovars isolated from sheep and goats, like those from cattle, exhibit multi-drug resistance and harbor antimicrobial resistance genes. Additionally, they possess diverse virulence factors that can threaten human health by spreading diseases and developing drug resistance, leading to antibiotic treatment failure.

Pre-Harvest Non-Typhoidal Salmonella Control Strategies in Commercial Layer Chickens

Non-typhoidal Salmonella (NTS) infections in poultry, particularly in commercial-layer chickens, pose a critical risk to food safety and public health worldwide. NTS bacteria can remain undetected in poultry flocks, contaminating products and potentially leading to gastroenteritis in humans. This review examines pre-harvest control strategies for NTS in layer chickens, including biosecurity protocols, vaccinations, feed additives, genetic selection, and environmental management. These strategies have substantially reduced Salmonella colonization and product contamination rates in the commercial layer industry. By evaluating these strategies, this review highlights the importance of integrated control measures to limit NTS colonization, reduce antimicrobial resistance, and improve poultry health. This review aims to provide producers, researchers, and policymakers with insights into effective practices to minimize Salmonella contamination and enhance both animal and human health outcomes.

Scoping Review About Salmonella spp. in Colombian Pig Farms from 2009 to Mid-2024

In Colombia, research on Salmonella concerning animal health, veterinary diagnostics, and epidemiology within the primary production chain is limited. This study aimed to analyze the published data about Salmonella in the Colombian primary pig production chain from 2009 to mid-2024. This involved an exploratory literature review using systematic search strategies, including articles, graduate studies, conference presentations, and technical reports from the selected period. Of the 35 studies reviewed, 30 met the inclusion criteria, with eleven being from the grey literature. The pooled prevalence of Salmonella spp. on Colombian farms was 8.9%, while the seroprevalence ranged from 27 to 40%. Risk factors associated with the presence of this bacterium on farms included aspects such as water sources, pest control, the farm type, and management practices. Few scientific publications address the presence of this pathogen in primary pig production in Colombia, underscoring the need to raise awareness within the academic and production communities about the importance of conducting and reporting new studies and cases.

Integron-Mediated Antimicrobial Resistance and Virulence Factors in Salmonella Typhimurium Isolated from Poultry

This study investigates antimicrobial-resistant (AMR) Salmonella Typhimurium in poultry, focusing on how class I integrons contribute to AMR and virulence. Using whole genome sequencing, researchers analyzed 26 S. Typhimurium isolates from U.S. poultry, finding that three isolates contained integrons (1000 base pairs each). These integron-positive isolates exhibited significantly higher resistance to beta-lactams, phenicols, and tetracyclines compared to integron-free isolates (p = 0.004, 0.009, and 0.02, respectively) and harbored genes like ges, imp, and oxa, which are linked to extended-spectrum beta-lactamase resistance. Most AMR gene classes (64%) were chromosome-based, with integron-positive isolates showing a broader array of resistance genes, including catB and tetA. Integron-bearing isolates had higher occurrences of bacteriocin genes and specific AMR genes like aminoglycoside and beta-lactam resistance genes, while integron-free isolates had more fimbrial and pilus genes. The presence of integrons may trend with increased AMR genes and virulence factors, highlighting the role of integron screening in enhancing AMR surveillance and reducing the need for high-priority antimicrobial treatments in poultry. These findings could support better AMR stewardship practices in poultry production, potentially lowering infection risks in humans and livestock.

Occurrence of Salmonella enterica in faecal sludge from Nigeria and genetic relatedness with strains associated with human infections in Africa

AIMS

This study investigated occurrence of Salmonella in faecal sludge from public toilets in Nigeria and genetic relatedness of strains that have been reported to cause human infection across Africa.

METHODS AND RESULTS

The study collected 150 human sludge from public toilets and identified Salmonella through culture and PCR. Isolates were tested for antimicrobial susceptibility and sequenced using Illumina MiSeq. Draft sequences were compared with sequence data from Enterobase and GenBank. Twenty-four (16.0%) of sewage samples were positive for Salmonella [CI95 (10.2-21.8)]. Salmonella serotype Give [sequence type (ST) 516], Salmonella serotype Seftenberg (ST-14), and Salmonella serotype Chester (ST-411) were the most prevalent serovars found in 45.8%, 16.7%, and 16.7% of samples, respectively. Most of the isolates were sensitive to the antimicrobials tested, only one isolate of Salmonella serotype Derby showed resistance to ampicillin and cefazolin. Notably, 91.7% of the strains had the aac (6)-Iaa gene and point mutations in parC, gyrA, and acrB. Salmonella serotype Chester showed genetic relatedness with strains from Benin Republic and South Africa.

CONCLUSIONS

There is genetic relatedness of present strains and those associated with human infections in Africa.

Genomic diversity of Salmonella Typhimurium and its monophasic variant in pig and pork production in France

Salmonella Typhimurium and its monophasic variant (Salmonella 4,[5],12:i:-) are among the most prevalent serovars worldwide. Even though these serovars have been the focus of many studies, their spread has not yet been investigated in French pig herds and slaughterhouses at a regional scale. Here, we characterized the genomic diversity of 188 Salmonella strains belonging to sequence type (ST) 19 and 34. These strains were isolated from pigs in metropolitan France between 2014 and 2019. Samples were collected from 10 regions, three of which together represent 75% of French pig production in 2020. To contextualize the French Salmonella genomes at a worldwide level, 193 ST 34 genomes from three continents and 14 countries were also included. This study revealed little diversity in ST 34 strains circulating in France, suggesting that one or two clones are spreading within pig herds and slaughterhouses. In silico virulence and antimicrobial resistance genes were investigated to understand the prevalence of these strains among farmed pigs and in the slaughterhouse environment. A comparison with ST 34 isolates from other countries highlighted the genomic specificity of the ST 34 monophasic variants in France, with some exceptions concerning isolates from bordering countries. This work provides new insights into the dynamics of S. Typhimurium and its monophasic variant sampled in French pig herds and slaughterhouses.

IMPORTANCE

Salmonellosis is a leading cause of bacterial infection in humans and animals around the world. This study provides a snapshot of the genomic diversity of one of the most prevalent Salmonella serovars (Salmonella Typhimurium and Salmonella 4,[5],12:i:-) circulating on French pig farms between 2013 and 2021. We investigated the link between geographical and genomic diversity. The analyses revealed little diversity of the strains, suggesting that one or two clones are spreading within French pig herds. We also in silico screened genetic elements that could explain the prevalence of these strains among farmed pigs and in the slaughterhouse environment. Finally, the comparison with isolates from other countries highlighted the genomic specificity of these two French sequence type 34 clones. This work provides new insights into the dynamics of S. Typhimurium and S. 4,[5],12:i:- sampled from pig herds and slaughterhouses in France, thus laying the foundations for future analyses.

Isolation and antimicrobial susceptibility profile of Salmonella species from slaughtered cattle carcasses and abattoir personnel at Dessie, municipality Abattoir, Northeast Ethiopia

BACKGROUND

Antibiotic-resistant Salmonella is one of the main public health concerns in the world. Isolation of Salmonella in abattoirs has been considered the core source of infection in the community from meat. Still, there is limited information on the contamination rate of cattle carcasses.

OBJECTIVE

This study aimed to document the occurrence and antimicrobial susceptibility profile of Salmonella species recovered from cattle carcass and abattoir personnel at Dessie, municipality abattoir, Northeast Ethiopia: METHODS: A total of 336 carcass swabs of abdomen, neck, and hind limb from cattle carcasses and 24 stool samples were collected from abattoir personnel using a systematic sampling method from February to April 2019. The collected samples were transported using Cary-Blair transport media and cultivated on Selenite cysteine F-broth, Brilliant green agar, and Xylose-lysine deoxycholate agar plates to isolate Salmonella species. Gram stain, colony morphology, and biochemical tests were performed to identify the isolated bacteria. An antimicrobial susceptibility test for Salmonella was performed using the Kirby-Bauer Disc Diffusion method. Descriptive statistics; both bivariable and multivariable logistic regression analysis was performed using SPSS version 25 software. P-value < 0.05 at 95% CI was considered statistically significant.

RESULTS

The prevalence of salmonella species was 8%(27/336) from all samples.'The prevalence of Salmonella isolates in cattle carcass and abattoir personnel was 8%(25/312) and 8.3%(2/24) respectively. The antimicrobial test showed that Salmonella species were 100% resistant to ampicillin, 59.3% to trimethoprim-sulfamethoxazole, 59.3% to tetracycline, and 55.6% to amoxicillin/clavulanate. From the total antimicrobial tested bacteria, 81.5%(22/27) were resistant to three and above classes of antibiotics (drug classes). Unwashed knives, carcasses, and hands of butchers during slaughtering were significantly associated (p < 0.05) with Salmonella found in carcasses.

CONCLUSIONS

Salmonella isolation rates from cattle carcasses were high, with the bacteria showing notable resistance to most tested antibiotics. Poor hygiene practices, unsanitized equipment, and unhygienic beef processing were contributing factors.

Sequence Types and Antimicrobial Resistance Profiles of Salmonella Typhimurium in the Food Chain in Singapore

Salmonella remains a significant foodborne pathogen globally with S. Typhimurium presenting as a frequently occurring serovar. This study aimed to characterize 67 S. Typhimurium isolates from humans, food, farms, and slaughterhouses collected in Singapore from 2016 to 2017. Using whole-genome sequencing analysis, the isolates were found to belong to either ST19 (n = 33) or ST36 (n = 34). ST36 predominated in human intestinal and chicken isolates, while human extra-intestinal and non-chicken food isolates belonged to ST19. Plasmids were predicted in 88.1% (n = 59) of the isolates with the most common incompatibility group profiles being IncFIB(S), IncFII(S) and IncQ1. IncFIB(S) (adjusted p-value < 0.05) and IncFII(S) (adjusted p-value < 0.05) were significantly more prevalent in ST19 isolates, while Col156 (adjusted p-value < 0.05) was more significantly found in ST36 isolates. ST36 isolates exhibited higher resistance to multiple antibiotic classes such as penicillins, phenicols, folate pathway inhibitors, aminoglycosides, β-lactam/β-lactamase inhibitor combinations, tetracyclines, and fluoroquinolones. Phylogenetics analysis suggested potential shared routes of transmission among human, chicken, farm and slaughterhouse environments. Taken together, this study offers a cross-sectional epidemiological insight into the genomic epidemiology and antimicrobial landscape of S. Typhimurium isolates in Singapore, informing strategies for future public health and food safety surveillance.

Small mammals as carriers of zoonotic bacteria on pig and cattle farms - Prevalence and risk of exposure in an integrative approach

To prevent foodborne infections from pigs and cattle, the whole food chain must act to minimize the contamination of products, including biosecurity measures which prevent infections via feed and the environment in production farms. Rodents and other small mammals can be reservoirs of and key vectors for transmitting zoonotic bacteria and viruses to farm animals, through direct contact but more often through environmental contamination. In line with One Health concept, we integrated results from a sampling study of small mammals in farm environments and data from a capture-recapture experiment into a probabilistic model which quantifies the degree of environmental exposure of zoonotic bacteria by small mammals to farm premises. We investigated more than 1200 small mammals trapped in and around 38 swine and cattle farm premises in Finland in 2017/2018. Regardless of the farm type, the most common species caught were the yellow-necked mouse (Apodemus flavicollis), bank vole (Clethrionomys glareolus), and house mouse (Mus musculus). Of 554 intestine samples (each pooled from 1 to 10 individuals), 33% were positive for Campylobacter jejuni. Yersinia enterocolitica was detected in 8% of the pooled samples, on 21/38 farm premises. Findings of Salmonella and the Shiga-toxin producing Escherichia coli (STEC) were rare: the pathogens were detected in only single samples from four and six farm premises, respectively. The prevalence of Campylobacter, Salmonella, Yersinia and STEC in small mammal populations was estimated as 26%/13%, 1%/0%, 2%/3%, 1%/1%, respectively, in 2017/2018. The exposure probability within the experimental period of four weeks on farms was 17-60% for Campylobacter and 0-3% for Salmonella. The quantitative model is readily applicable to similar integrative studies. Our results indicate that small mammals increase the risk of exposure to zoonotic bacteria in animal production farms, thus increasing risks also for livestock and human health.

Investigation of prevalence and antimicrobial resistance of Salmonella in pet dogs and cats in Turkey

BACKGROUND

Although salmonellosis is considered to be a foodborne zoonotic disease, pets can play a significant role in the dissemination of antimicrobial-resistant Salmonella organisms to humans because of close contact with their owners.

OBJECTIVES

To determine the prevalence, risk factors, virulence factors, serotypes, and antimicrobial resistance profile of Salmonella in pet dogs and cats in Turkey and to assess the public health risk. Furthermore, to perform macroscopic comparison of lactic acid bacteria (LAB) in Salmonella-positive and Salmonella-negative animals.

METHODS

International Standards Organization (ISO) 6579-1:2017 and Food and Drug Administration (FDA) methods were used to compare the effectiveness of culture methods in the identification of Salmonella in 348 rectal swabs. Positive isolates were serotyped using the slide agglutination method according to the White-Kauffmann-Le Minor scheme and the presence of virulence genes (invA and stn) were evaluated by polymerase chain reaction (PCR). Antimicrobial activity was tested by Kirby-Bauer disk diffusion method according to Clinical and Laboratory Standards Institute (CLSI) guidelines.

RESULTS

Salmonella prevalence was 5.73% (9/157) in dogs and 0.0% (0/191) in cats. Eight (8/9) isolates were cultured with the ISO method and 5 (5/9) isolates were cultured with the FDA method. Macroscopic results revealed that Salmonella agents had no effect on LAB. Three different serotypes were detected and all isolates were positive for virulence genes. Antibiotic resistance profiling indicated that 11.1% of the isolates were MDR and the highest resistance was found for ciprofloxacin. MDR-resistant S. Virchow and carbapenem-resistant S. Enteritidis were detected from dog isolates. There was a significant difference between raw meat consumption and Salmonella carriage (p < 0.01).

CONCLUSIONS

Dogs could be potential carriers of Salmonella infection. The isolation of Salmonella in healthy dogs instead of dogs suffering from diarrhoea indicates that attention should be paid to asymptomatic carriage. The emergence of resistance among zoonotic Salmonella isolates poses a significant threat to public health.

Tackling salmonellosis: A comprehensive exploration of risks factors, impacts, and solutions

Salmonellosis, caused by Salmonella species, is one of the most common foodborne illnesses worldwide with an estimated 93.8 million cases and about 155,00 fatalities. In both industrialized and developing nations, Salmonellosis has been reported to be one of the most prevalent foodborne zoonoses and is linked with arrays of illness syndromes such as acute and chronic enteritis, and septicaemia. The two major and most common Salmonella species implicated in both warm-blooded and cold-blooded animals are Salmonella bongori and Salmonella enterica. To date, more than 2400 S. enterica serovars which affect both humans and animals have been identified. Salmonella is further classified into serotypes based on three primary antigenic determinants: somatic (O), flagella (H), and capsular (K). The capacity of nearly all Salmonella species to infect, multiply, and survive in human host cells with the aid of their pathogenic and virulence arsenals makes them deadly and important public health pathogens. Primarily, food-producing animals such as poultry, swine, cattle, and their products have been identified as important sources of salmonellosis. Additionally, raw fruits and vegetables are among other food types that have been linked to the spread of Salmonella spp. Based on the clinical manifestation of human salmonellosis, Salmonella strains can be categorized as either non-typhoidal Salmonella (NTS) and typhoidal Salmonella. The detection of aseptically collected Salmonella in necropsies, environmental samples, feedstuffs, rectal swabs, and food products serves as the basis for diagnosis. In developing nations, typhoid fever due to Salmonella Typhi typically results in the death of 5%-30% of those affected. The World Health Organization (WHO) calculated that there are between 16 and 17 million typhoid cases worldwide each year, with scaring 600,000 deaths as a result. The contagiousness of a Salmonella outbreak depends on the bacterial strain, serovar, growth environment, and host susceptibility. Risk factors for Salmonella infection include a variety of foods; for example, contaminated chicken, beef, and pork. Globally, there is a growing incidence and emergence of life-threatening clinical cases, especially due to multidrug-resistant (MDR) Salmonella spp, including strains exhibiting resistance to important antimicrobials such as beta-lactams, fluoroquinolones, and third-generation cephalosporins. In extreme cases, especially in situations involving very difficult-to-treat strains, death usually results. The severity of the infections resulting from Salmonella pathogens is dependent on the serovar type, host susceptibility, the type of bacterial strains, and growth environment. This review therefore aims to detail the nomenclature, etiology, history, pathogenesis, reservoir, clinical manifestations, diagnosis, epidemiology, transmission, risk factors, antimicrobial resistance, public health importance, economic impact, treatment, and control of salmonellosis.

The biogenesis, identification, and functionality of circWWP2 in lipopolysaccharide stimulated macrophages

CircRNA, a non-coding RNA, is an ideal biomarker and a suitable potential therapeutic target for various disease due to its high stability, species conservation and cell/tissue specificity. Our previous study has found a circular RNA WWP2 (circWWP2) was significantly decreased in chicken macrophages during bacterial infection. However, the function of circWWP2 in chicken macrophages remains unclear. In this study, it was demonstrated that circWWP2 was a stable circular RNA created by back-splicing of exons 2 to 4 of WWP2 via PCR amplification, Sanger sequencing, RNase R exonuclease digestion, and RT-qPCR. Moreover, bioinformatics analysis showed circWWP2 could interact with 13 miRNAs and target 3,264 genes, which were significantly enriched in lysosomes, IgA-producing intestinal immune networks for IgA production, and Notch signaling pathway. Furthermore, CCK8 and RT-qPCR indicated that overexpression of circWWP2 could promote lipopolysaccharide (LPS)-induced cellular injury by decreasing cell viability and increasing the expression levels of pro-inflammatory cytokines and pro-apoptosis genes, and NO production. CircWWP2 may exert a potential target for the treatment of bacterial infection. Further experiments are necessary to validate the specific mechanism that circWWP2 regulates LPS induced cellular immune responses.

Study of Salmonella spp. from Cage Papers Belonging to Pet Birds in an Argentinean Canary Breeder Championship

Birds, including canaries and other birds, have become increasingly popular as pets. Bird fairs, where breeders gather and show their production in a championship setting, present a setting for possible Salmonella spp. contamination and transmission. Therefore, this study estimated the rate of Salmonella spp. isolation from cage papers, located in the bottom of cages of exotic pet birds, including canaries. Collected Salmonella isolates were used to determine the antimicrobial resistance profile to 52 antibiotics and 17 commercial disinfectants, based on pure or a mixture of acids, alcohols, aldehydes, alkalis, halogens, peroxygen, and quaternary ammonium compounds. The samples consisted of 774 cage papers taken in the 2015 Argentinean canary breeder championship, pooling three cage papers into one sterile sampling bag. Only one pool of the cage papers was positive for Salmonella spp. (0.4%), which belonged to the sample from three frill canary cages. Two strains of Salmonella serotype Glostrup were isolated, which were only resistant to sulfonamides and erythromycin and sensitive to alkali-based product PL301 AS. Although the rate of Salmonella spp. isolation from cage papers in an Argentinean canary breeder championship is low, it should not be discounted because Salmonella ser. Glostrup can be a source of human Salmonella outbreaks and they show high resistance to disinfecting products.

Emergence of Salmonella Infantis carrying the pESI megaplasmid in commercial farms of five major integrated broiler operations in Korea

Considering Salmonella transmission occurs through several routes in integrated broiler operations, control of nontyphoidal Salmonella in commercial farms is essential. This study aimed to compare the distribution of persistent Salmonella serovars in environments and dead chickens between 5 major integrated broiler operations in Korea. The prevalence of Salmonella-positive farms in dust prior to placement by operations was 0 to 25%, but the prevalence in dust and feces at the time of depletion was increased to 16.7 to 41.7% and 16.7 to 66.7%, respectively. Moreover, the prevalence of farms with Salmonella in chickens that died within 1 week old and at 4 to 5 weeks old ranged from 8.3 to 58.3% and 16.7 to 41.7%, respectively. The prevalence of Salmonella enterica serovar Infantis-positive farms in dust prior to placement and in chickens that died within 1 week old was 5.2 and 3.4%, respectively, but the prevalence in dust and feces at the time of depletion and in chickens that died at 4 to 5 weeks old was significantly increased to 27.6, 41.4, and 20.7%, respectively (P < 0.05). Interestingly, the plasmid of emerging S. Infantis (pESI) was only identified in S. Infantis, and the prevalence of multidrug-resistance was significantly higher in pESI-positive S. Infantis (99.2%) than in pESI-negative S. Infantis (6.7%) (P < 0.05). The distribution of pulsotypes between pESI-positive and pESI-negative S. Infantis were varied, but a majority of S. Infantis were clustered only 2 pulsotypes. Moreover, pESI-positive S. Infantis harbored more virulence factors than pESI-negative S. Infantis. This study is the first report on characteristics of S. Infantis carrying the pESI plasmid in commercial broiler farms in Korea.

Frequency of isolation and phenotypic antimicrobial resistance of fecal Salmonella enterica recovered from dairy cattle in Canada

Salmonellosis is one of the leading causes of gastrointestinal infections in humans. In Canada, it is estimated that approximately 87,500 cases of salmonellosis occur every year in humans, resulting in 17 deaths. In the United States, it is estimated that 26,500 hospitalizations and 420 deaths occur every year. In dairy cattle, infections caused by nontyphoidal Salmonella enterica can cause mild to severe disease, including enteritis, pneumonia, and septicemia. Our study objectives were to determine the proportion of fecal samples positive for Salmonella in dairy cattle in Canada and determine the resistance pattern of these isolates. We used data collected through the Canadian Dairy Network for Antimicrobial Stewardship and Resistance (CaDNetASR). Pooled fecal samples from preweaning calves, postweaning heifers, lactating cows, and manure storage were cultured for Salmonella, and the isolates were identified using matrix-assisted laser desorption/ionization-time of flight mass spectrometry. Antimicrobial susceptibilities were determined using the minimum inhibitory concentration test, and resistance interpretation was made according to the Clinical and Laboratory Standards Institute. A 2-level, multivariable logistic regression model was built to determine the probability of recovering Salmonella from a sample, accounting for province, year, and sample source. The proportion of farms with at least one positive sample were 12% (17/140), 19% (28/144), and 17% (24/144) for the sampling years 2019, 2020, and 2021, respectively. Out of the 113 Salmonella isolates, 23 different serovars were identified. The occurrence of Salmonella appeared to be clustered by farms and provinces. The most common serovars identified were Infantis (14%) and Typhimurium (14%). Overall, 21% (24/113) of the Salmonella isolates were resistant to at least one antimicrobial. Resistance to tetracycline was commonly observed (17%); however, very limited resistance to category I antimicrobials (categorization according to Health Canada that includes third-generation cephalosporins, fluoroquinolones, polymyxins, and carbapenems) was observed, with one isolate resistant to amoxicillin and clavulanic acid. The proportion of Salmonella isolates resistant to 2 and 3 antimicrobial classes was 3.5% and 8.8%, respectively. Our study provided valuable information on the proportion of fecal samples positive for Salmonella, the serovars identified, and the associated resistance patterns across CaDNetASR herds, at regional and national levels.

Emergence of Poultry-Associated Human Salmonella enterica Serovar Abortusovis Infections, New South Wales, Australia

Salmonella enterica serovar Abortusovis is a ovine-adapted pathogen that causes spontaneous abortion. Salmonella Abortusovis was reported in poultry in 2009 and has since been reported in human infections in New South Wales, Australia. Phylogenomic analysis revealed a clade of 51 closely related isolates from Australia originating in 2004. That clade was genetically distinct from ovine-associated isolates. The clade was widespread in New South Wales poultry production facilities but was only responsible for sporadic human infections. Some known virulence factors associated with human infections were only found in the poultry-associated clade, some of which were acquired through prophages and plasmids. Furthermore, the ovine-associated clade showed signs of genome decay, but the poultry-associated clade did not. Those genomic changes most likely led to differences in host range and disease type. Surveillance using the newly identified genetic markers will be vital for tracking Salmonella Abortusovis transmission in animals and to humans and preventing future outbreaks.

A Review on Microbiological Source Attribution Methods of Human Salmonellosis: From Subtyping to Whole-Genome Sequencing

Salmonella is one of the main causes of human foodborne illness. It is endemic worldwide, with different animals and animal-based food products as reservoirs and vehicles of infection. Identifying animal reservoirs and potential transmission pathways of Salmonella is essential for prevention and control. There are many approaches for source attribution, each using different statistical models and data streams. Some aim to identify the animal reservoir, while others aim to determine the point at which exposure occurred. With the advance of whole-genome sequencing (WGS) technologies, new source attribution models will greatly benefit from the discriminating power gained with WGS. This review discusses some key source attribution methods and their mathematical and statistical tools. We also highlight recent studies utilizing WGS for source attribution and discuss open questions and challenges in developing new WGS methods. We aim to provide a better understanding of the current state of these methodologies with application to Salmonella and other foodborne pathogens that are common sources of illness in the poultry and human sectors.

Infant Salmonella enterica Meningitis: A Rare Case Report and Review of Literature

Meningitis caused by Salmonella enterica can be a fatal condition that is more common in low- and middle-income countries and uncommon in infants. This case of a 2-month-old male infant reported Salmonella meningitis symptoms, such as fever, irritability, altered sensorium, and diarrhoea. Clinical examination revealed bulging anterior fontanelles, dehydration, and sunken eyes. Screening for normal hearing, cranial ultrasound, and magnetic resonance imaging (MRI) revealed no brain abnormalities. A cerebrospinal fluid (CSF) culture revealed gram-negative Salmonella enterica bacilli. Treatment with meropenem and ampicillin was initiated after antibiotic susceptibility testing showed sensitivity. The patient's cerebrospinal fluid parameters and bacterial growth improved after antibiotic therapy. Two weeks later, the baby was neurologically healthy and discharged. Paediatricians should be aware that Salmonella enterica can cause meningitis in children with non-specific symptoms.

Outlining the Phytoconstituents of Greek Clover Herb Extract and Assessment of Its Effect against Foodborne Infections Caused by Salmonella typhimurium

Owing to the spread of resistance between pathogenic bacteria, searching for novel compounds with antibacterial activity is essential. Here, we investigated the potential antibacterial activity of Greek clover or Trigonella foenum-graecum herb extract on Salmonella typhimurium clinical isolates. The chemical profile of the herb was initially determined using LC-ESI-MS/MS, which explored 36 different compounds. Interestingly, the fenugreek extract possessed antibacterial action in vitro with minimum inhibitory concentrations of 64 to 512 µg/mL. The potential mechanism of action was studied by elucidating the effect of the fenugreek extract on the membrane properties of S. typhimurium bacteria, including the inner and outer membrane permeability and membrane integrity. Remarkably, the fenugreek extract had detrimental effects on the membrane properties in 40-60% of the isolates. Moreover, the in vivo antibacterial action was studied using a gastrointestinal infection model with S. typhimurium bacteria. Interestingly, the fenugreek extract (200 mg/kg) improved the infection outcomes in the tested mice. This was represented by the noteworthy decrease (p < 0.05) in the bacterial count in the small intestine and caecum tissues. The survival rate of the fenugreek-extract-treated mice significantly increased compared to the S. typhimurium-infected group. Additionally, there was an improvement in the histological and immunohistochemical features of tumor necrosis factor-alpha. In addition, using an ELISA and qRT-PCR, there was an improvement in the proinflammatory and oxidative stress markers in the fenugreek-extract-treated group. Consequently, fenugreek extract should be investigated further on other food pathogens.

MARCKS Inhibition Alters Bovine Neutrophil Responses to Salmonella Typhimurium

Neutrophils are innate immune cells that respond quickly to sites of bacterial infection and play an essential role in host defense. Interestingly, some bacterial pathogens benefit from exuberant neutrophil inflammation. Salmonella is one such pathogen that can utilize the toxic mediators released by neutrophils to colonize the intestine and cause enterocolitis. Because neutrophils can aid gut colonization during Salmonella infection, neutrophils represent a potential host-directed therapeutic target. Myristoylated alanine-rich C-kinase substrate (MARCKS) is an actin-binding protein that plays an essential role in many neutrophil effector responses. We hypothesized that inhibition of MARCKS protein would alter bovine neutrophil responses to Salmonella Typhimurium (STm) ex vivo. We used a MARCKS inhibitor peptide to investigate the role of MARCKS in neutrophil responses to STm. This study demonstrates that MARCKS inhibition attenuated STm-induced neutrophil adhesion and chemotaxis. Interestingly, MARCKS inhibition also enhanced neutrophil phagocytosis and respiratory burst in response to STm. This is the first report describing the role of MARCKS protein in neutrophil antibacterial responses.

Salmonella Vitkin Outbreak Associated with Bearded Dragons, Canada and United States, 2020-2022

We identified 2 cases of Salmonella enterica serovar Vitkin infection linked by whole-genome sequencing in infants in Ontario, Canada, during 2022. Both households of the infants reported having bearded dragons as pets. The outbreak strain was also isolated from an environmental sample collected from a patient's bearded dragon enclosure. Twelve cases were detected in the United States, and onset dates occurred during March 2021-September 2022 (isolates related to isolates from Canada within 0-9 allele differences by core-genome multilocus sequence typing). Most US patients (66.7%) were <1 year of age, and most (72.7%) had reported bearded dragon exposure. Hospitalization was reported for 5 (38.5%) of 13 patients. Traceback of bearded dragons identified at least 1 potential common supplier in Southeast Asia. Sharing rare serovar information and whole-genome sequencing data between Canada and the United States can assist in timely identification of outbreaks, including those that might not be detected through routine surveillance.

Enterococcus contamination of infant foods and implications for exposure to foodborne pathogens in peri-urban neighbourhoods of Kisumu, Kenya

We collected infant food samples from 714 households in Kisumu, Kenya, and estimated the prevalence and concentration of Enterococcus, an indicator of food hygiene conditions. In a subset of 212 households, we quantified the change in concentration in stored food between a morning and afternoon feeding time. In addition, household socioeconomic characteristics and hygiene practices of the caregivers were documented. The prevalence of Enterococcus in infant foods was 50% (95% confidence interval: 46.1 - 53.4), and the mean log10 colony-forming units (CFUs) was 1.1 (SD + 1.4). No risk factors were significantly associated with the prevalence and concentration of Enterococcus in infant foods. The mean log10 CFU of Enterococcus concentration was 0.47 in the morning and 0.73 in the afternoon foods with a 0.64 log10 mean increase in matched samples during storage. Although no factors were statistically associated with the prevalence and the concentration of Enterococcus in infant foods, household flooring type was significantly associated with an increase in concentration during storage, with finished floors leading to 1.5 times higher odds of concentration increase compared to unfinished floors. Our study revealed high prevalence but low concentration of Enterococcus in infant food in low-income Kisumu households, although concentrations increased during storage implying potential increases in risk of exposure to foodborne pathogens over a day. Further studies aiming at investigating contamination of infant foods with pathogenic organisms and identifying effective mitigation measures are required to ensure infant food safety.

Salmonellosis: An Overview of Epidemiology, Pathogenesis, and Innovative Approaches to Mitigate the Antimicrobial Resistant Infections

Salmonella is a major foodborne pathogen and a leading cause of gastroenteritis in humans and animals. Salmonella is highly pathogenic and encompasses more than 2600 characterized serovars. The transmission of Salmonella to humans occurs through the farm-to-fork continuum and is commonly linked to the consumption of animal-derived food products. Among these sources, poultry and poultry products are primary contributors, followed by beef, pork, fish, and non-animal-derived food such as fruits and vegetables. While antibiotics constitute the primary treatment for salmonellosis, the emergence of antibiotic resistance and the rise of multidrug-resistant (MDR) Salmonella strains have highlighted the urgency of developing antibiotic alternatives. Effective infection management necessitates a comprehensive understanding of the pathogen's epidemiology and transmission dynamics. Therefore, this comprehensive review focuses on the epidemiology, sources of infection, risk factors, transmission dynamics, and the host range of Salmonella serotypes. This review also investigates the disease characteristics observed in both humans and animals, antibiotic resistance, pathogenesis, and potential strategies for treatment and control of salmonellosis, emphasizing the most recent antibiotic-alternative approaches for infection control.

Enduring pathogenicity of African strains of Salmonella on plastics and glass in simulated peri-urban environmental waste piles

In low- and middle-income countries, plastic has become a major constituent of landfills and urban dump sites. Environmental plastic pollution can also provide a novel surface for the formation of microbial biofilm, which often includes pathogenic bacteria and viruses. Here, under conditions simulating a peri-urban waste pile typical of an African informal settlement, we aimed to determine if pathogenic Salmonella spp. can retain their virulence following a prolonged period of desiccation on the surfaces of environmental plastic and glass. We show that clinically (and environmentally) relevant strains of Salmonella including S. Enteritidis, S. Typhimurium and S. Typhi can persist on plastic and glass for at least 28-days and that temperature (which increases with the depth of an urban waste pile) is a key determinant of this survival. All three strains of Salmonella retained their pathogenicity (determined by using a Galleria mellonella model of infection) following their recovery from the plastisphere indicating that plastics in the environment can act as reservoirs for human pathogens and could facilitate their persistence for extended periods of time. Pathogens colonising environmental plastic waste therefore pose a heightened public health risk, particularly in areas where people are frequently exposed to plastic pollution.

[Quantitative Analysis and Characteristics of Salmonella from Retail Chicken Meat Products in Japan]

From October 2020 to February 2021, a total of 95 retail chicken meat products from 39 retail meat shops in Tokyo Metropolis and Kanagawa Prefecture, Japan, were collected and examined for the prevalence of Salmonella to assess public health implications. If a sample tested positive for Salmonella, a quantitative analysis was performed using the three-tube most probable number (MPN) method. Of 95 retail chicken meat products, Salmonella was isolated from 30 samples (31.6%). The levels of Salmonella contamination ranged from <0.3 to 4.3 MPN/g. The most frequent level was <0.3 MPN/g (63.3%). Of the 33 Salmonella strains isolated, four serotypes were identified: S. Schwarzengrund (60.6%), S. Infantis (24.2%), S. Agona (12.1%), and S. Manhattan (3.0%). Multilocus sequence typing (MLST) analysis classified most S. Schwarzengrund isolates into sequence type (ST) 241, the same ST found in chicken meat in Japan, except for one isolate. Of the 33 Salmonella isolates, 29 (87.9%) were antibiotic resistant. Twenty-six isolates (78.8%) showed multidrug resistance to two or more antibiotics. Therefore, these results indicate that retail chicken meat products in Japan are an important source of Salmonella infection in humans and that Salmonella contamination in retail chicken products seems to originate from chicken meat.

Ciprofloxacin-resistant ST198 Salmonella Kentucky in a hospitalized American black bear (Ursus americanus), with evidence of subsequent nosocomial transmission

Global emergence of ciprofloxacin-resistant ST198 Salmonella Kentucky poses an important public health threat. While conducting Salmonella surveillance among wildlife patients admitted to our veterinary medical teaching hospital in central New York, we isolated multidrug-resistant (MDR) ST198 Salmonella Kentucky from an American black bear (Ursus americanus) in September 2020. The isolate was phenotypically resistant to numerous antimicrobial agents, including ceftriaxone and ciprofloxacin, and several antimicrobial resistance genes and mutational resistance determinants were detected. Between April and July 2021, the same strain of MDR ST198 Salmonella Kentucky was also isolated from seven other wildlife patients and multiple hospital environmental locations, suggesting nosocomial transmission. Ciprofloxacin resistance is conferred by triple point mutations in the quinolone resistance-determining regions (QRDRs), a genotypic profile indicative of Clade ST198.2. To our knowledge, this is the first report of this ciprofloxacin-resistant clade being identified in animals or animal products in the United States. Timely resolution of the outbreak was achieved following efforts to further enhance environmental disinfection protocols and biosecurity measures at the hospital, with no known cases or positive environmental samples after July 2021.

Bat-associated microbes: Opportunities and perils, an overview

The potential biotechnological uses of bat-associated bacteria are discussed briefly, indicating avenues for biotechnological applications of bat-associated microbes. The uniqueness of bats in terms of their lifestyle, genomes and molecular immunology may predispose bats to act as disease reservoirs. Molecular phylogenetic analysis has shown several instances of bats harbouring the ancestral lineages of bacterial (Bartonella), protozoal (Plasmodium, Trypanosoma cruzi) and viral (SARS-CoV2) pathogens infecting humans. Along with the transmission of viruses from bats, we also discuss the potential roles of bat-associated bacteria, fungi, and protozoan parasites in emerging diseases. Current evidence suggests that environmental changes and interactions between wildlife, livestock, and humans contribute to the spill-over of infectious agents from bats to other hosts. Domestic animals including livestock may act as intermediate amplifying hosts for bat-origin pathogens to transmit to humans. An increasing number of studies investigating bat pathogen diversity and infection dynamics have been published. However, whether or how these infectious agents are transmitted both within bat populations and to other hosts, including humans, often remains unknown. Metagenomic approaches are uncovering the dynamics and distribution of potential pathogens in bat microbiomes, which might improve the understanding of disease emergence and transmission. Here, we summarize the current knowledge on bat zoonoses of public health concern and flag the gaps in the knowledge to enable further research and allocation of resources for tackling future outbreaks.

Development and application of a competitive ELISA for the detection of antibodies against Salmonella Abortusequi in equids

The high abortion rate associated with Salmonella Abortusequi (S. Abortusequi) infection in equids has re-emerged over the past 10 years and has caused serious economic losses to China. Our previous studies showed that the flagellin FljB gene could distinguish S. Abortusequi from most Salmonella serotypes. In this study, the flagellin antigen was used to develop a competitive enzyme-linked immunosorbent assay (cELISA) that could be used to detect both horse and donkey serum samples using a monoclonal antibody (MAb) that was found to bind to FljB. A cELISA was established using the purified MAb coating of the plate and incubation of the mixture of horseradish peroxidase (HRP)-conjugated FljB antigen with the undiluted serum sample. The performance of the cELISA and the tube agglutination test (TAT) assay was compared with respect to sensitivity and specificity, by testing a panel containing 660 S. Abortusequi-positive and 515 S. Abortusequi-negative serum samples, all of which had been characterized by Western blotting. Receiver operator characteristic (ROC) analyses were performed to determine the cutoff value and estimate the detection specificity (Sp) and sensitivity (Se). ROC analysis showed that the area under the ROC curve (AUC) values of cELISA [AUC = 0.9941; 95% confidence interval (CI), 0.9898-0.9984] were higher than those of TAT (AUC = 0.7705; 95% Cl, 0.7437-0.7972). A cutoff value of 39.5% was selected with Sp and Se values of 100 (95% Cl, 99.26-100.00) and 97.58 (95% Cl, 96.10-98.50), respectively. The cELISA has excellent futures compared with TAT, such as shortened detection time, no need for pre-treatment of sera, and easy interpretation of the results, and is more suitable for disease surveillance.

Synergistic Strategies of Heat and Peroxyacetic Acid Disinfection Treatments for Salmonella Control

The food industry has recognized a pressing need for highly effective disinfection protocols to decrease the risk of pathogen emergence and proliferation in food products. The integration of antimicrobial treatments in food production has occurred as a potential strategy to attain food items of superior quality with respect to microbiological safety and sensory attributes. This study aims to investigate the individual and synergistic effects of heat and peroxyacetic acid on the inactivation of bacterial cells, considering various contact times and environmental conditions. Four Salmonella serotypes, isolated from industrial meat production surfaces, were employed as model organisms. By systematically assessing the impacts of individual factors and synergistic outcomes, the effectiveness of bacterial cell inactivation and the efficiency of heat and peroxyacetic acid could be predicted. To better approximate real-world food processing conditions, this study also incorporated a bovine albumin-rich condition as a simulation of the presence of organic loads in processing steps. The findings revealed the essential need for a synergistic interplay of investigated parameters with the following optimized values: 1.5% concentration of peroxyacetic acid, temperature range of 60-65 °C, and contact time of 3 min for the complete effect regardless of the degree of contamination.

Parasites and zoonotic bacteria in the feces of cats and dogs from animal shelters in Carinthia, Austria

Due to their close associations with humans, dogs and cats can be important reservoirs for zoonotic pathogens. In the current study 200 fecal samples of dogs (n = 70 samples) and cats (n = 130 samples) from animal shelters in Carinthia, southern Austria, were examined for the presence of parasites (fecal flotation and larval migration assay) and selected bacteria. Overall, 17.1% of the canine and 38.5% of the feline samples were positive for parasites (p < 0.001), most commonly Giardia duodenalis (dogs and cats), including potentially zoonotic genotypes revealed by multilocus genotyping, and Toxocara cati (cats). Cryptosporidium (C. felis), Cystoisospora spp. (dogs and cats), hookworms (dog), Trichuris (dog) Capillaria hepatica (cats), taeniids (cat), and Aelurostrongylus abstrusus (cat) were also found. Zoonotic bacteria were detected in 10.5% of the samples, Salmonella enterica (dogs), Campylobacter jejuni (dogs and cats) and Yersinia enterocolitica (cat) and were significantly associated with parasite infections in cats but not in dogs. Samples that were positive for several pathogens were common; especially G. duodenalis and T. cati were frequently found in association with each other, other parasites or bacteria. The spectrum of detected pathogens is comparable to that of other dog and cat populations in central Europe. However, since animals from shelters are frequently rehomed, diagnostic measures, appropriate hygiene and therapy as well as training of shelter staff are recommended to prevent zoonotic transmission of enteropathogens to staff or new owners. The presence of heteroxenic parasites, i.e. Aelurostrongylus abstrusus and Taenia taeniaeformis, and spurious excretion of Ca. hepatica in cats, indicates that these animals preyed on intermediate hosts, and that biosafety measures in pet shelters need to be evaluated for their efficacy in the prevention of pathogen transmission.

A Systematic review on Prevalence, Serotypes and Antibiotic resistance of Salmonella in Ethiopia, 2010-2022

Background

In Ethiopia, salmonellosis is one of the most common zoonotic and foodborne illnesses. Ethiopia continues to be at risk for its fast-expanding medication resistance. For the development of preventative and control methods, summarized knowledge regarding salmonellosis is necessary. Determining a thorough evaluation of the prevalence, serotypes, and antibiotic resistance of Salmonella in humans and animals from January 1, 2010, to December 30, 2022, in Ethiopia was our goal.

Methods

To find Salmonella related articles that published in English, we used the Google Scholar and PubMed search engines. Three researchers conducted the eligible studies using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist, making sure to include the necessary keywords. If studies were duplicates, incomplete publications, or reported without an antimicrobial test were excluded. Excel 2013 was used to calculate frequencies and tabulate data.

Results

There were a total of 43 investigations from food handlers, diarrhoeic patients, and animals. The prevalence rates ranged from 1% to 10% and 1% to 13% among food handlers and diarrhoea patients, respectively. The highest prevalence was among pigs (41.6%). S. Anatum in animals and S. Typhimurium in people were the predominant serotypes. Amoxicillin and ampicillin were claimed to be 100% resistant in human studies. The highest recorded resistances for ceftriaxone and ciprofloxacin were 16.7% and 100%, respectively. Animal studies revealed that Salmonella resistances to ampicillin, streptomycin and tetracycline were 100%, 90%, 86.4%, respectively. S. Kentucky showed complete resistance to tetracycline, ampicillin, gentamicin, ciprofloxacin, and streptomycin.

Conclusion

The prevalence of Salmonella among asymptomatic food handlers, diarrheal patients and animals were high in Ethiopia. S. Typhimurium that have the zoonotic importance was presented predominantly in human study. High levels of resistances were showed to tetracycline, ampicillin and streptomycin in animal studies. Salmonellosis prevention and control techniques should be strengthened.

The epidemiology of fecal carriage of nontyphoidal Salmonella among healthy children and adults in three sites in Kenya

BACKGROUND

Despite the importance of non-Typhoidal Salmonella (NTS) disease in Africa, epidemiologic data on carriage and transmission are few. These data are important to understand the transmission of NTS in Africa and to design control strategies.

METHOD

To estimate the prevalence of stool carriage of NTS in Kenya, we conducted a cross-sectional study in Kilifi, Nairobi, and Siaya, sites with a low, moderate and high incidence of invasive NTS disease, respectively. At each site, we randomly selected 100 participants in each age-group of 0-11 months, 12-59 months, 5-14 years, 15-54 years and ≥55 years. We collected stool, venous blood (for hemoglobin and malaria rapid tests), anthropometric measurements, and administered a questionnaire on Water Access Sanitation and Hygiene (WASH) practices. Stool samples were cultured on selective agar for Salmonella; suspect isolates underwent serotyping and antimicrobial susceptibility testing.

RESULT

Overall, 53 (3.5%) isolates of NTS were cultured from 1497 samples. Age-adjusted prevalence was 13.1% (95%CI 8.8-17.4) in Kilifi, 0.4% (95%CI 0-1.3) in Nairobi, and 0.9% (95%CI 0-2.0) in Siaya. Prevalence was highest among those aged 15-54 years (6.2%). Of 53 isolates; 5 were S. Enteritidis, 1 was S. Typhimurium. No S. Typhi was isolated. None of the risk factors were associated with carriage of NTS. All isolates were susceptible to all antibiotics tested, including ampicillin, chloramphenicol, ciprofloxacin and co-trimoxazole.

CONCLUSION

Prevalence of fecal carriage was high in Kilifi, an area of low incidence of invasive NTS disease and was low in areas of higher incidence in Nairobi and Siaya. The age-prevalence, risk factors, geographical and serotype distribution of NTS in carriage differs from invasive disease.

Prevention and Control of Human Salmonella enterica Infections: An Implication in Food Safety

Salmonella is a foodborne zoonotic pathogen causing diarrhoeal disease to humans after consuming contaminated water, animal, and plant products. The bacterium is the third leading cause of human death among diarrhoeal diseases worldwide. Therefore, human salmonellosis is of public health concern demanding integrated interventions against the causative agent, Salmonella enterica. The prevention of salmonellosis in humans is intricate due to several factors, including an immune-stable individual infected with S. enterica continuing to shed live bacteria without showing any clinical signs. Similarly, the asymptomatic Salmonella animals are the source of salmonellosis in humans after consuming contaminated food products. Furthermore, the contaminated products of plant and animal origin are a menace in food industries due to Salmonella biofilms, which enhance colonization, persistence, and survival of bacteria on equipment. The contaminated food products resulting from bacteria on equipment offset the economic competition of food industries and partner institutions in international business. The most worldwide prevalent broad-range Salmonella serovars affecting humans are Salmonella Typhimurium and Salmonella Enteritidis, and poultry products, among others, are the primary source of infection. The broader range of Salmonella serovars creates concern over multiple strategies for preventing and controlling Salmonella contamination in foods to enhance food safety for humans. Among the strategies for preventing and controlling Salmonella spread in animal and plant products include biosecurity measures, isolation and quarantine, epidemiological surveillance, farming systems, herbs and spices, and vaccination. Other measures are the application of phages, probiotics, prebiotics, and nanoparticles reduced and capped with antimicrobial agents. Therefore, Salmonella-free products, such as beef, pork, poultry meat, eggs, milk, and plant foods, such as vegetables and fruits, will prevent humans from Salmonella infection. This review explains Salmonella infection in humans caused by consuming contaminated foods and the interventions against Salmonella contamination in foods to enhance food safety and quality for humans.

Ion channel function in translational bovine gallbladder cholangiocyte organoids: establishment and characterization of a novel model system

The study of biliary physiology and pathophysiology has long been hindered by the lack of in vitro models that accurately reflect the complex functions of the biliary system. Recent advancements in 3D organoid technology may offer a promising solution to this issue. Bovine gallbladder models have recently gained attention in the investigation of human diseases due to their remarkable similarities in physiology and pathophysiology with the human gallbladder. In this study, we have successfully established and characterized bovine gallbladder cholangiocyte organoids (GCOs) that retain key characteristics of the gallbladder in vivo, including stem cell properties and proliferative capacity. Notably, our findings demonstrate that these organoids exhibit specific and functional CFTR activity. We believe that these bovine GCOs represent a valuable tool for studying the physiology and pathophysiology of the gallbladder with human significance.

Development and Application of an iELISA for the Detection of Antibody against Salmonella Abortusequi

Equine abortus salmonellosis is a bacterial disease that causes high abortion rates in susceptible equids and therefore significant economic losses. Although the tube agglutination test (TAT) is a commonly used serological test for S. Abortusequi, it is not highly specific or sensitive, and the development of more sensitive, specific and rapid assays is therefore urgently required. In this study, an indirect enzyme-linked immunosorbent assay (iELISA) was developed for the specific detection of flagellum protein (FljB) antibodies against S. Abortusequi. Negative sera from horses in China (n = 1030) were used to establish the baseline for a negative population, and reference antisera positive against other viruses or bacteria were used to test the cross reactivity of the technique. The performance of the FljB iELISA was evaluated against that of the standard TAT, and was tested using field serum samples. The FljB iELISA assay was 8-16 times more sensitive than TAT. ROC analysis showed that the FljB iELISA was accurate, with an area under the curve (AUC) = 0.9943 (95% CI, 0.9815-1.000). The diagnostic sensitivity (DSe) of the FljB iELISA was 98.9% (95% Cl, 93.84%-100.00%), which was higher than that of TAT (DSe 38.6; 95% CI, 29.14%-49.08%). The diagnostic specificity (DSp) of the iELISA was 100.0% (95% CI, 95.82%-100.0%). When the 508 clinical samples were tested, the FljB iELISA had a positive detection rate of 51.38% (261/508, 95% CI, 51.24%-51.51%), which was higher than that of TAT (44/508). We also performed a serological survey for S. Abortusequi infection, using a series of samples collected from across eighteen provinces of China in 2021. The results showed that all provinces except Jiangsu had a certain number of cases, and the positive rates ranged from 0% to 96.9%, indicating the wide spread of S. Abortusequi in China. The abovementioned results suggest that the FljB iELISA developed in this study is rapid, sensitive, specific, and repeatable and is likely to be a suitable test for large-scale serological surveys for the detection and control of S. Abortusequi infection.

Prevalence Estimation, Antimicrobial Susceptibility, and Serotyping of Salmonella enterica Recovered from New World Non-Human Primates (Platyrrhini), Feed, and Environmental Surfaces from Wildlife Centers in Costa Rica

Concern about zoonoses and wildlife has increased. Few studies described the role of wild mammals and environments in the epidemiology of Salmonella. Antimicrobial resistance is a growing problem associated with Salmonella that threatens global health, food security, the economy, and development in the 21st century. The aim of this study is to estimate the prevalence and identify antibiotic susceptibility profiles and serotypes of non-typhoidal Salmonella enterica recovered from non-human primate feces, feed offered, and surfaces in wildlife centers in Costa Rica. A total of 180 fecal samples, 133 environmental, and 43 feed samples from 10 wildlife centers were evaluated. We recovered Salmonella from 13.9% of feces samples, 11.3% of environmental, and 2.3% of feed samples. Non-susceptibility profiles included six isolates from feces (14.6%): four non-susceptible isolates (9.8%) to ciprofloxacin, one (2.4%) to nitrofurantoin, and one to both ciprofloxacin and nitrofurantoin (2.4%). Regarding the environmental samples, one profile was non-susceptible to ciprofloxacin (2.4%) and two to nitrofurantoin (4.8%). The serotypes identified included Typhimurium/I4,[5],12:i:-, S. Braenderup/Ohio, S. Newport, S. Anatum/Saintpaul, and S. Westhampton. The epidemiological surveillance of Salmonella and antimicrobial resistance can serve in the creation of strategies for the prevention of the disease and its dissemination throughout the One Health approach.

Cell membrane-coated nanoparticles: An emerging antibacterial platform for pathogens of food animals

Bacterial pathogens of animals impact food production and human health globally. Food animals act as the major host reservoirs for pathogenic bacteria and thus are highly prone to suffer from several endemic infections such as pneumonia, sepsis, mastitis, and diarrhea, imposing a major health and economical loss. Moreover, the consumption of food products of infected animals is the main route by which human beings are exposed to zoonotic bacteria. Thus, there is excessive and undue administration of antibiotics to fight these virulent causative agents of food-borne illness, leading to emergence of resistant strains. Thus, highprevalence antibiotic-resistant resistant food-borne bacterial infections motivated the researchers to discover new alternative therapeutic strategies to eradicate resistant bacterial strains. One of the successful therapeutic approach for the treatment of animal infections, is the application of cell membrane-coated nanoparticles. Cell membranes of several different types of cells including platelets, red blood cells, neutrophils, cancer cells, and bacteria are being wrapped over the nanoparticles to prepare biocompatible nanoformulations. This diversity of cell membrane selection and together with the possibility of combining with an extensive range of nanoparticles, has opened a new opportunistic window for the development of more potentially effective, safe, and immune evading nanoformulations, as compared to conventionally used bare nanoparticle. This article will elaborately discuss the discovery and development of novel bioinspired cell membrane-coated nanoformulations against several pathogenic bacteria of food animals such as Klebsiella pneumoniae, Escherichia coli, Staphylococcus aureus, Salmonella enteritidis, Campylobacter jejuni, Helicobacter pylori, and Group A Streptococcus and Group B Streptococcus.

Disease Occurrence in- and the Transferal of Zoonotic Agents by North American Feedlot Cattle

North America is a large producer of beef and contains approximately 12% of the world's cattle inventory. Feedlots are an integral part of modern cattle production in North America, producing a high-quality, wholesome protein food for humans. Cattle, during their final stage, are fed readily digestible high-energy density rations in feedlots. Cattle in feedlots are susceptible to certain zoonotic diseases that impact cattle health, growth performance, and carcass characteristics, as well as human health. Diseases are often transferred amongst pen-mates, but they can also originate from the environment and be spread by vectors or fomites. Pathogen carriage in the gastrointestinal tract of cattle often leads to direct or indirect contamination of foods and the feedlot environment. This leads to the recirculation of these pathogens that have fecal-oral transmission within a feedlot cattle population for an extended time. Salmonella, Shiga toxin-producing Escherichia coli, and Campylobacter are commonly associated with animal-derived foods and can be transferred to humans through several routes such as contact with infected cattle and the consumption of contaminated meat. Brucellosis, anthrax, and leptospirosis, significant but neglected zoonotic diseases with debilitating impacts on human and animal health, are also discussed.

A longitudinal study to examine the influence of farming practices and environmental factors on pathogen prevalence using structural equation modeling

The contamination of fresh produce with foodborne pathogens has been an on-going concern with outbreaks linked to these commodities. Evaluation of farm practices, such as use of manure, irrigation water source, and other factors that could influence pathogen prevalence in the farming environment could lead to improved mitigation strategies to reduce the potential for contamination events. Soil, water, manure, and compost were sampled from farms in Ohio and Georgia to identify the prevalence of Salmonella, Listeria monocytogenes (Lm), Campylobacter, and Shiga-toxin-producing Escherichia coli (STEC), as well as Arcobacter, an emerging human pathogen. This study investigated agricultural practices to determine which influenced pathogen prevalence, i.e., the percent positive samples. These efforts identified a low prevalence of Salmonella, STEC, and Campylobacter in soil and water (< 10%), preventing statistical modeling of these pathogens. However, Lm and Arcobacter were found in soil (13 and 7%, respectively), manure (49 and 32%, respectively), and water samples (18 and 39%, respectively) at a comparatively higher prevalence, suggesting different dynamics are involved in their survival in the farm environment. Lm and Arcobacter prevalence data, soil chemical characteristics, as well as farm practices and weather, were analyzed using structural equation modeling to identify which factors play a role, directly or indirectly, on the prevalence of these pathogens. These analyses identified an association between pathogen prevalence and weather, as well as biological soil amendments of animal origin. Increasing air temperature increased Arcobacter and decreased Lm. Lm prevalence was found to be inversely correlated with the use of surface water for irrigation, despite a high Lm prevalence in surface water suggesting other factors may play a role. Furthermore, Lm prevalence increased when the microbiome's Simpson's Diversity Index decreased, which occurred as soil fertility increased, leading to an indirect positive effect for soil fertility on Lm prevalence. These results suggest that pathogen, environment, and farm management practices, in addition to produce commodities, all need to be considered when developing mitigation strategies. The prevalence of Arcobacter and Lm versus the other pathogens suggests that multiple mitigation strategies may need to be employed to control these pathogens.

A Familiar Outbreak of Monophasic Salmonella serovar Typhimurium (ST34) Involving Three Dogs and Their Owner's Children

Salmonella is a Gram-negative enteric bacterium responsible for the foodborne and waterborne disease salmonellosis, which is the second most reported bacterial zoonosis in humans. Many animals are potential sources of salmonellosis, including dogs, cats, and other pets. We report the case of an outbreak of salmonellosis in a family in central Italy, affecting two children and involving their three dogs as carriers. One of the children needed medical care and hospitalisation. Isolation and analysis of stool samples from the sibling and the animals present in the house were carried out. Serotyping allowed the identification of S. enterica subsp. enterica serovar Typhimurium in its monophasic variant for all the isolates. The results of whole-genome sequencing confirmed that the strains were tightly related. The minimum inhibitory concentration (MIC) test documented the resistance to ampicillin, sulfamethoxazole, and tetracycline. The origin of the zoonotic outbreak could not be assessed; however, the case study showed a clear passage of the pathogen between the human and non-human members of the family. The possibility of a transmission from a dog to a human suggests the need for further studies on the potential ways of transmission of salmonellosis through standard and alternative feed.

Salmonella Enteritidis Fatal Septicemia with Meningoencephalitis in a Tiger (Panthera tigris) Cub

A 15-day-old, female, captive Panthera tigris cub was hospitalized after developing severe hyperthermia, depression, and lack of appetite. The clinical condition rapidly worsened, and the tiger cub died in 72 h after the onset of neurological symptoms, septic shock, and multiple organ dysfunction syndrome. The postmortem main gross findings consisted of a severe and diffuse bilateral fibrino-suppurative meningoencephalitis and ventriculitis, mild fibrinous and sero-hemorrhagic polyserositis and cystitis, severe pulmonary edema, and hemorrhages. Microscopically, the meninges, ependyma, and choroid plexuses were diffusely expanded by abundant infiltration of neutrophils and macrophages, with multifocal fibrinous exudation. Histiocytic interstitial pneumonia, fibrinous and neutrophilic polyserositis, and pyelocystitis were also observed. Vascular thrombosis with multifocal vasculitis and vascular necrosis were frequently observed. Aerobic and anaerobic cultures performed on the brain, lungs, intestine, kidneys, and in pericardial effusion reported the presence of Salmonella enterica subsp. enterica serovar Enteritidis. Environmental and nutritional contamination were identified as putative sources of infections. To the best of the authors’ knowledge, this is the first report of Salmonella Enteritidis septicemia with meningoencephalitis in a tiger cub, which highlights the need to further investigate the cause of acute perinatal death to reduce the risk of infectious disease outbreaks.