Virulence Gene Profile, Antimicrobial Resistance and Multilocus Sequence Typing of Salmonella enterica Subsp. enterica Serovar Enteritidis from Chickens and Chicken Products

Epidemiological and Whole Genome Sequencing Analysis of Restaurant Salmonella Enteritidis Outbreak Associated with an Infected Food Handler in Jiangxi Province, China, 2023

In China, Salmonella is one of the most frequent causes of bacterial gastroenteritis, and food handlers in restaurants as an important contaminated source were rarely reported. In May 2023, an outbreak of Salmonella enterica serovar Enteritidis infection in a restaurant in Jiangxi Province, China, was investigated. Cases were interviewed. Stool samples from cases, anal swabs from restaurant employees, suspicious raw food materials, and semifinished food were collected and examined. Pulsed-field gel electrophoresis (PFGE) and whole genome sequencing (WGS) were performed to determine the relatedness of the pathogen isolates. Antimicrobial resistance genes and virulence genes of isolates were analyzed by WGS. The antimicrobial profile of the isolates was detected by broth microdilution, which involved 20 different antibiotics. Among the 31 patrons, 26 showed gastrointestinal symptoms. Five Salmonella Enteritidis strains were isolated from patients (2), semifinished food (2), and food handler (1). The results of PFGE and single-nucleotide polymorphism showed that these five isolates were identical clones. These findings demonstrated that this outbreak was a restaurant Salmonella Enteritidis outbreak associated with an infected food handler. The rates of resistance to nalidixic acid and colistin and intermediate resistance to ciprofloxacin were 100%, 80%, and 100%, respectively. These outbreak isolates harbored point mutation gyrA p.D87G. The cause of inconsistency between the genotype and phenotype of resistance was deeply discussed. A total of 107 virulence genes were found in each isolate, with many being associated with Salmonella pathogenicity island (SPI)-1 and SPI-2. As an overlooked contamination source, infected food handlers can easily cause large-scale outbreaks. This outbreak highlighted that the government should enhance the training and supervision of food hygiene and safety for food handlers to prevent foodborne outbreaks.

Rapid and sensitive detection of Salmonella in agro-Food and environmental samples: A review of advances in rapid tests and biosensors

Salmonella is as an intracellular bacterium, causing many human fatalities when the host-specific serotypes reach the host gastrointestinal tract. Nontyphoidal Salmonella are responsible for numerous foodborne outbreaks and product recalls worldwide whereas typhoidal Salmonella are responsible for Typhoid fever cases in developing countries. Yet, Salmonella-related foodborne disease outbreaks through its food and water contaminations have urged the advancement of rapid and sensitive Salmonella-detecting methods for public health protection. While conventional detection methods are time-consuming and ineffective for monitoring foodstuffs with short shelf lives, advances in microbiology, molecular biology and biosensor methods have hastened the detection. Here, the review discusses Salmonella pathogenic mechanisms and its detection technology advancements (fundamental concepts, features, implementations, efficiency, benefits, limitations and prospects). The time-efficiency of each rapid test method is discussed in relation to their limit of detections (LODs) and time required from sample enrichment to final data analysis. Importantly, the matrix effects (LODs and sample enrichments) were compared within the methods to potentially speculate Salmonella detection from environmental, clinical or food matrices using certain techniques. Although biotechnological advancements have led to various time-efficient Salmonella-detecting techniques, one should consider the usage of sophisticated equipment to run the analysis by moderately to highly trained personnel. Ultimately, a fast, accurate Salmonella screening that is readily executed by untrained personnels from various matrices, is desired for public health procurement.

Antimicrobial Resistance Profiles and Molecular Characteristics of Salmonella enterica Serovar Agona Isolated from Food-Producing Animals During 2010-2020 in South Korea

Multidrug-resistant (MDR) Salmonella enterica serovar Agona infections affect public health globally. This investigation aimed to ascertain the antimicrobial resistance profiles and molecular characteristics of Salmonella Agona isolates obtained from food-producing animals. A total of 209 Salmonella Agona isolates were recovered from mostly chickens (139 isolates), pigs (56 isolates), cattle (11 isolates), and ducks (3 isolates) between 2010 and 2020 in South Korea. In addition, these Salmonella Agona isolates were obtained from 25 slaughterhouses nationwide. Furthermore, this serotype suddenly increased in chickens in 2020. Salmonella Agona from chickens showed high resistance (69-83%) to ampicillin, streptomycin, tetracycline, trimethoprim/sulfamethoxazole, and chloramphenicol. Moreover, chicken/duck isolates (83.1%) showed significantly higher levels of MDR than cattle/pig isolates (1.5%). For molecular analysis by pulsed-field gel electrophoresis, infrared spectroscopy biotyping, and multilocus sequence typing in combination, a total of 23 types were observed. Especially two major types, P1-III-2-13 and P1-IV-2-13, comprised 59.3% of the total isolates spreading in most farms. Moreover, Salmonella Agona sequence type (ST)13 was predominant (96.7%) among three different STs (ST13, ST11, and ST292) widely detected in chickens (94.3%) in most farms located nationwide. Taken together, MDR Salmonella Agona in chickens might pose a potential risk to public health through direct contact or the food chain.

Genetic Characteristics of Salmonella Isolates Recovered From Reused Broiler Litter Over Three Successive Flocks

Salmonella infections are a leading cause of bacterial food-borne illness worldwide. Infections are highly associated with the consumption of contaminated food, and in particular, chicken meat. The severity of Salmonella infections depends on the presence of antimicrobial resistance genes and virulence factors. While there are many studies which have investigated Salmonella strains isolated from postharvest chicken samples, there is a gap in our understanding of the genetic properties that influence the persistence of Salmonella in preharvest and in particular their makeup of antimicrobial resistance genes and virulence factors. We used whole genome sequencing and hierarchical clustering to characterize and classify the genetic diversity of Salmonella enterica isolates (n = 55) recovered from the litter of commercial broiler chicken raised in four colocated broiler houses of one integrated farm over three consecutive flocks. The chicken were raised under a newly adopted "No Antibiotics Ever" program, and copper sulfate was administered via drinking water. In-silico serovar prediction identified three S. enterica serovars: Enteritidis (n = 12), Kentucky (n = 40), and Senftenberg (n = 3). Antimicrobial susceptibility testing revealed that only one S. Kentucky isolate was resistant to streptomycin, while the remaining isolates were susceptible to all antibiotics tested. Metal resistance operons, including copper and silver, were identified chromosomally and on plasmids in serovar Senftenberg and Kentucky isolates, respectively, while serovar Enteritidis carried several virulence factors on plasmids. Serovar Kentucky isolates harboring metal resistance operons were the only Salmonella isolates recovered from the litter of third flock cohort. These results suggest that there might be environmental selection for Salmonella strains carrying plasmid-associated metal resistance and virulence genes, which could play a role in their persistence in litter.

An in-vivo experimental evaluation of the efficacy of fish-derived antimicrobial peptides against multidrug-resistant Pseudomonas aeruginosa

Introduction

due to the fact that antimicrobial peptides antimicrobial peptides (AMPs) from climbing perch have not been fully explored for their antimicrobial potency, this investigation was undertaken to explore that possibility.

Methods

antimicrobial peptides (AMPs) from the mucous secretion of climbing perch were obtained and an in-vivo analysis was conducted using mice.

Results

the results showed inhibitory effects on multidrug-resistant multidrug-resistant Pseudomonas aeruginosa with reduced mortality from 100% among the non-treated group to 25%. Similarly, the level of serum transaminase enzymes (AST and ALT), creatinine levels, and pro-inflammatory cytokines (TNF-α and IL-6) were all found to be higher in the non-treatment group compared to the AMP-treatment group. Also, extensive tissue damage in the lung, liver, and spleen of the non-treated control group mice was observed based on the histopathological lesions recorded. As expected, AMPs from climbing perch significantly alleviated multidrug-resistant P. aeruginosa infection in-vivo and produced enhanced therapeutic efficacy superior to the ciprofloxacin treatment.

Conclusion

this study provides insight into the potential antimicrobial activity of fish innate immune system-derived peptides that could serve as a candidate for the substitute of antibiotics.

Genomic characterization of Salmonella isolated from retail chicken and humans with diarrhea in Qingdao, China

Salmonella, especially antimicrobial resistant strains, remains one of the leading causes of foodborne bacterial disease. Retail chicken is a major source of human salmonellosis. Here, we investigated the prevalence, antimicrobial resistance (AMR), and genomic characteristics of Salmonella in 88 out of 360 (24.4%) chilled chicken carcasses, together with 86 Salmonella from humans with diarrhea in Qingdao, China in 2020. The most common serotypes were Enteritidis and Typhimurium (including the serotype I 4,[5],12:i:-) among Salmonella from both chicken and humans. The sequence types were consistent with serotypes, with ST11, ST34 and ST19 the most dominantly identified. Resistance to nalidixic acid, ampicillin, tetracycline and chloramphenicol were the top four detected in Salmonella from both chicken and human sources. High multi-drug resistance (MDR) and resistance to third-generation cephalosporins resistance were found in Salmonella from chicken (53.4%) and humans (75.6%). In total, 149 of 174 (85.6%) Salmonella isolates could be categorized into 60 known SNP clusters, with 8 SNP clusters detected in both sources. Furthermore, high prevalence of plasmid replicons and prophages were observed among the studied isolates. A total of 79 antimicrobial resistant genes (ARGs) were found, with aac(6')-Iaa, blaTEM-1B, tet(A), aph(6)-Id, aph(3″)-Ib, sul2, floR and qnrS1 being the dominant ARGs. Moreover, nine CTX-M-type ESBL genes and the genes blaNMD-1, mcr-1.1, and mcr-9.1 were detected. The high incidence of MDR Salmonella, especially possessing lots of mobile genetic elements (MGEs) in this study posed a severe risk to food safety and public health, highlighting the importance of improving food hygiene measures to reduce the contamination and transmission of this bacterium. Overall, it is essential to continue monitoring the Salmonella serotypes, implement the necessary prevention and strategic control plans, and conduct an epidemiological surveillance system based on whole-genome sequencing.

Mobile genetic elements drive the multidrug resistance and spread of Salmonella serotypes along a poultry meat production line

The presence of mobile genetic elements in Salmonella isolated from a chicken farm constitutes a potential risk for the appearance of emerging bacteria present in the food industry. These elements contribute to increased pathogenicity and antimicrobial resistance through genes that are related to the formation of biofilms and resistance genes contained in plasmids, integrons, and transposons. One hundred and thirty-three Salmonella isolates from different stages of the production line, such as feed manufacturing, hatchery, broiler farm, poultry farm, and slaughterhouse, were identified, serotyped and sequenced. The most predominant serotype was Salmonella Infantis. Phylogenetic analyses demonstrated that the diversity and spread of strains in the pipeline are serotype-independent, and that isolates belonging to the same serotype are very closely related genetically. On the other hand, Salmonella Infantis isolates carried the pESI IncFIB plasmid harboring a wide variety of resistance genes, all linked to mobile genetic elements, and among carriers of these plasmids, the antibiograms showed differences in resistance profiles and this linked to a variety in plasmid structure, similarly observed in the diversity of Salmonella Heidelberg isolates carrying the IncI1-Iα plasmid. Mobile genetic elements encoding resistance and virulence genes also contributed to the differences in gene content. Antibiotic resistance genotypes were matched closely by the resistance phenotypes, with high frequency of tetracycline, aminoglycosides, and cephalosporins resistance. In conclusion, the contamination in the poultry industry is described throughout the entire production line, with mobile genetic elements leading to multi-drug resistant bacteria, thus promoting survival when challenged with various antimicrobial compounds.

Salmonella spp. in Chicken: Prevalence, Antimicrobial Resistance, and Detection Methods

Multidrug-resistant Salmonella spp. is one of the leading causes of worldwide foodborne disease outbreaks. Animal-derived foods, particularly chicken and poultry products, are the most likely source of Salmonella transmission to humans. The increasing demand for chicken meat has raised a global food safety issue. This review aims to determine the prevalence and antimicrobial resistance of Salmonella spp. in chickens from various countries in Asia. The methods for detecting Salmonella will also be discussed in this review. The prevalence of Salmonella spp. in chicken and poultry products is lower in developed countries than in developing countries. In addition, the incidence of Salmonella spp. in chicken and poultry products from fresh markets is higher than those from supermarkets. Furthermore, this review also reported the presence of multidrug-resistant Salmonella strains in various Asian countries. Rapid Salmonella detection based on immunological assays, molecular-based assays, and biosensors can provide more accurate results with high sensitivity and specificity. These methods also require a shorter time than the cultural-based Salmonella detection method. The use of suitable detection methods to determine the presence of Salmonella spp. in chicken and poultry products is important to ensure food safety.

HOW MISUSE OF ANTIMICROBIAL AGENTS IS EXACERBATING THE CHALLENGES FACING SOMALIA'S PUBLIC HEALTH

Background

In contrast to most developed countries, antimicrobial resistance (AMR) has continued to be a serious challenge to public health in the majority of resource-limited countries in Africa.

Materials and method

A comprehensive review of all available literature reporting on antimicrobial resistance patterns, antimicrobial drug usage in both human and animals, as well as national AMR regulations in Somalia was undertaken.

Results

The review observed that successful AMR control and surveillance among resource-poor nations are affected by a lack of infrastructural and institutional capacities, poor investment in human and material resources, as well as non-adherence to available policies. The humanitarian crisis affecting Somalia has persisted for too long, leading to loss of lives, productivity and dilapidation of public health infrastructures. Somalia like most countries has adopted the One Health approach in developing their soon-to-be gazetted National Action Plan on AMR, which covers both human health, animal health and the environment. Although there are many other similar policy documents and guidelines regulating the usage and administration of antimicrobials in the country, evidence of the implementation indicates there is still a need for more effort.

Conclusion

AMR constitute a significant public health problem in Somali, and there is urgent need for gazetting and enforcement of the newly developed national policy. In addition, there is also the need for collaboration with the major stakeholders to develop workable solutions to combat the hazards posed by AMR in the country.

Characterisation of Salmonella Enteritidis ST11 and ST1925 Associated with Human Intestinal and Extra-Intestinal Infections in Singapore

Salmonella Enteritidis is a major foodborne pathogen worldwide. In this study, a total of 276 S. enteritidis isolates, collected between 2016 and 2017 from human, food and farm/slaughterhouse samples, were studied to enhance the understanding of the epidemiology of human salmonellosis in Singapore. Results showed all 276 isolates belonged either to ST1925 (70.3%) or ST11 (29.7%), with ST11 being significantly more frequent in extra-intestinal isolates and chicken isolates. Food isolates, most of which were from poultry, showed the highest prevalence of resistance (33–37%) against beta-lactams or beta-lactams/beta-lactamase inhibitor combination (ampicillin, piperacillin and ampicillin/sulbactam). The analysis showed the detection of genes associated with resistance to aminoglycoside genes (99.6%), tetracycline (55.1%), and beta-lactams (14.9%) of all isolates. Nine types of plasmids were found in 266 isolates; the most common incompatibility group profiles were IncFIB(S)-IncFII(S)-IncX1 (72.2%) and IncFIB(S)-IncFII(S) (15.8%). Most plasmid harbouring isolates from chicken (63.6%, 14/22) and from human (73.8%, 175/237) shared the same plasmid profile (IncFIB(S)-IncFII(S)-IncX1). SNP analysis showed clustering of several isolates from poultry food products and human isolates, suggesting phylogenetic relatedness among these isolates. Lastly, this study provides important epidemiological insights on the application of phenotypic and next-generation sequencing (NGS) tools for improved food safety and public health surveillance and outbreak investigation of S.enteritidis.