Foodborne Infections Research Articles

Impact of climate change on foodborne infections and intoxications.

Temperature, precipitation, and humidity are important factors that can influence the spread, reproduction, and survival of pathogens. Climate change affects these factors, resulting in higher air and water temperatures, increased precipitation, or water scarcity. Climate change may thus have an increasing impact on many infectious diseases. The present review considers those foodborne pathogens and toxins in animal and plant foods that are most relevant in Germany, on the basis of a selective literature review: the bacterial pathogens of the genera Salmonella, Campylobacter and Vibrio, parasites of the genera Cryptosporidium and Giardia, and marine biotoxins. As climate change continues to progress, all infections and intoxications discussed here can be expected to increase in Germany. The expected increase in foodborne infections and intoxications presents a growing public health risk in Germany.

Genetic diversity, antibiotic resistance, and virulence characteristics of Staphylococcus aureus from raw milk over 10 years in Shanghai

Staphylococcus aureus (S. aureus) is a major cause of foodborne infections and its persistence in raw milk is a multifaceted phenomenon that poses a considerable public health challenge. Our study investigated the prevalence, virulence genes, antibiotic resistance, and genetic characterization of S. aureus in raw milk in six Shanghai districts from 2013 to 2022. At 18 dairy farms, a total of 704 S. aureus strains were isolated from 1799 samples tested for drug sensitivity. The highest rates of antibiotic resistance were ampicillin (96.7 %), sulfamethoxazole (65 %), and erythromycin (21.6 %). Between 2018 and 2022, there was a significant decrease in the resistance rates of ceftiofur, ofloxacin, tilmicosin, erythromycin, clindamycin, amoxicillin-clavulanic acid, and sulfamethoxazole in comparison to the period from 2013 to 2017. There were 205 S. aureus strains chosen for whole genome sequencing (WGS), with no more than 2 strains of the same resistance phenotype from each farm per year. The prevalence of mecA-positive strains was 14.15 %, while other antibiotic resistance-associated genes were observed as follows: blaI (70.21 %), lnu(B) (5.85 %), lsa(E) (5.75 %), fexA (6.83 %), erm(C) (4.39 %), tet(L) (9.27 %), and dfrG (5.85 %). Isolates harboring the immune evasion cluster (IEC) genes (scn, chp, and sak) were predominantly categorized as sequence types (STs) 7, 188, 15, 59, and 398. The predominant cluster complexes were CC97, CC1, CC398, and CC1651. In 2017–2022, there was a transition in CC1 from the highly antibiotic-resistant ST9 strain that emerged between 2013 and 2018 to the low-resistant but highly virulent ST1 strain. Retrospective phylogenetic analysis elucidated the evolutionary history of the isolates and demonstrated that the human-animal host transition of S. aureus was linked to the genesis of MRSA CC398. The implementation of extended surveillance will aid in the development of innovative strategies to avoid the transmission of S. aureus along the dairy food chain and the occurrence of public health events.

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

International travel and the globalization of food supplies have increased the risk of epidemic foodborne infections. Salmonella strains, particularly non-typhoidal Salmonella (NTS), are major zoonotic pathogens responsible for gastrointestinal diseases worldwide. In this study, the prevalence and Salmonella contamination in pigs/carcasses throughout the South Korean pig supply chain and the associated risk factors were evaluated using Systematic reviews and meta-analyses (SRMA), and quantitative microbial risk assessment (QMRA). The prevalence of Salmonella in finishing pigs, which is one of the major starting inputs of the QMRA model was calculated through SRMA of studies conducted in south Korea in order to complement and enhance the robustness of the model. Our findings revealed that the pooled Salmonella prevalence in pigs was 4.15% with a 95% confidence interval (CI) of 2.56 to 6.66%. Considering the pig supply chain, the highest prevalence was detected in slaughterhouses (6.27% [95% CI: 3.36; 11.37]), followed by farms (4.16% [95% CI: 2.32; 7.35]) and meat stores (1.21% [95% CI: 0.42; 3.46]). The QMRA model predicted a 3.9% likelihood of Salmonella-free carcasses and a 96.1% probability of Salmonella-positive carcasses at the end of slaughter, with an average Salmonella concentration of 6.38 log CFU/carcass (95% CI: 5.17; 7.28). This corresponds to an average contamination of 1.23 log CFU/g (95% CI: 0.37; 2.48) of pork meat. Across the pig supply chain, the highest Salmonella contamination was predicted after transport and lairage, with an average concentration of 8 log CFU/pig (95% CI: 7.15; 8.42). Sensitivity analysis indicated that Salmonella fecal shedding (r = 0.68) and Salmonella prevalence in finishing pigs (r = 0.39) at pre-harvest were the most significant factors associated with Salmonella contamination in pork carcasses. Although disinfection and sanitation interventions along the slaughter line can reduce contamination levels to some extent, effective measures should be taken to reduce Salmonella prevalence at the farm level to improve the safety of pork consumption.

Repression of Staphylococcus aureus and Escherichia coli by Lactiplantibacillus plantarum Strain AG10 in Drosophila melanogaster In Vivo Model.

Probiotic bacteria exhibiting antagonistic activities against pathogenic bacteria are widely considered as potential options for the prevention and treatment of various infectious diseases and represent potential substitutes of antibiotics. Here we show that the L. plantarum AG10 strain represses the growth of Staphylococcus aureus and Escherichia coli in vitro and diminishes their negative effects in vivo in a Drosophila melanogaster model of survival on embryonic (larvae) and pupa stages. In an agar drop diffusion test, L. plantarum AG10 exhibited antagonistic properties against Escherichia coli, Staphylococcus aureus, Serratia marcescens and Pseudomonas aeruginosa, and repressed the growth of E. coli and S. aureus during milk fermentation. In a Drosophila melanogaster model, L. plantarum AG10 alone did not provide any significant effect, either during the embryonic stage or during further development of the flies. Despite this, it was able to restore the viability of groups infected with either E. coli and S. aureus, almost to the level of non-treated control at all stages of development (larvae, pupa and adult). Moreover, in the presence of L. plantarum AG10, pathogens-induced mutation rates and recombination events reduced 1.5-2-fold. The genome of L. plantarum AG10 was sequenced and deposited at NCBI under the accession number PRJNA953814 and consists of annotated genome and raw sequence data. It consists of 109 contigs and is 3,479,919 bp in length with a GC content of 44.5%. The analysis of the genome has revealed considerably few putative virulence factors and three genes responsible for the biosynthesis of putative antimicrobial peptides, with one of them exhibiting a high probability of antimicrobial properties. Taken together, these data allow the suggestion that the L. plantarum AG10 strain is promising for use in both dairy production and probiotics as a preservative from foodborne infections.

Whole-Genome Sequencing of Shiga Toxin-Producing Escherichia coli for Characterization and Outbreak Investigation.

Shiga toxin-producing Escherichia coli (STEC) causes high frequencies of foodborne infections worldwide and has been linked to numerous outbreaks each year. Pulsed-field gel electrophoresis (PFGE) has been the gold standard for surveillance until the recent transition to whole-genome sequencing (WGS). To further understand the genetic diversity and relatedness of outbreak isolates, a retrospective analysis of 510 clinical STEC isolates was conducted. Among the 34 STEC serogroups represented, most (59.6%) belonged to the predominant six non-O157 serogroups. Core genome single nucleotide polymorphism (SNP) analysis differentiated clusters of isolates with similar PFGE patterns and multilocus sequence types (STs). One serogroup O26 outbreak strain and another non-typeable (NT) strain, for instance, were identical by PFGE and clustered together by MLST; however, both were distantly related in the SNP analysis. In contrast, six outbreak-associated serogroup O5 strains clustered with five ST-175 serogroup O5 isolates, which were not part of the same outbreak as determined by PFGE. The use of high-quality SNP analyses enhanced the discrimination of these O5 outbreak strains into a single cluster. In all, this study demonstrates how public health laboratories can more rapidly use WGS and phylogenetics to identify related strains during outbreak investigations while simultaneously uncovering important genetic attributes that can inform treatment practices.

Prevalence and Antibiotic Susceptibility Profile of Staphylococcus aureus in Commercialized Food in Oran, Algeria

Background: With regard to health-threatening infections, Staphylococcus aureus is the leading cause of polymorphic infections varying from a banal tegumentary infection to numerous lethal illnesses. Furthermore, it is the third commonest bacterial cause of food-borne infections worldwide.This study aimed to investigate contamination, prevalence, and antibiotic resistance of S. aureus isolated from several widely marketed food products (raw and processed) in the region of Oran, Algeria. Methods: A total of 350 food samples including prepared meals (n=110), dairy products (n=42), pastry (n=78), meat and its derivatives (n=97), and other commercially available foods (egg products, sweets, and sauces) (n=23) have been randomly purchased from diverse sale outlets and screened for S. aureus strains during the period from July 2021 to September 2022. The isolation and identication of S. aureus bacteria were preformed using conventional culture and biochemical tests such as catalase, coagulase, and DNase tests. Furthermore, the strains were screened for their resistance to five different antimicrobial drugs using the agar diffusion method. Results: The overall prevalence of S. aureus determined among the collecteded samples was 31.14% (109/350), where, pastry products harbored the highest contamination rate (43.59%), and prepared meals, the lowest contamination rate (18.18%). The strains presented a high level of resistance (58.71-39.44%) for gentamycin and oxacilin, respectively. Moreover, the lowest level of resistance was observed against erythromycin 16.51%, and about 83% of strains presented multidrug resistance. Conclusion: The significative prevalence and the high level of multidrug resistant of S. aureus highlights the seriousness to improve food contamination prevention programs and underlines that good hygiene practices at sale outlets has a major impact on the sanitary quality of commercialized food products.

How to? My first experience as a sports doctor (GOTS young academy presentation)

Non-typhoidal Salmonella (NTS) is the major cause of foodborne infections globally, with considerable morbidity and mortality. The accurate identification of Salmonella serovars is important in disease management and public health surveillance. However, traditional serotyping methods are laborious, time-consuming and may produce ambiguous results. In this study, we evaluated traditional serotyping and seven gene-based multilocus sequence typing (MLST) methods to determine the serogroups of Salmonella strains. This study analysis suggests that MLST based serotyping is accurate in serogroup identification and discrimination of Salmonella serovars compared to the traditional serotyping method and can be implemented in routine clinical practice.

Is it time to move on to gene-based Salmonella typing: Evidence and implications

Non-typhoidal Salmonella (NTS) is the major cause of foodborne infections globally, with considerable morbidity and mortality. The accurate identification of Salmonella serovars is important in disease management and public health surveillance. However, traditional serotyping methods are laborious, time-consuming and may produce ambiguous results. In this study, we evaluated traditional serotyping and seven gene-based multilocus sequence typing (MLST) methods to determine the serogroups of Salmonella strains. This study analysis suggests that MLST based serotyping is accurate in serogroup identification and discrimination of Salmonella serovars compared to the traditional serotyping method and can be implemented in routine clinical practice.

Prevalence and Antimicrobial-Resistant Patterns of Non-typhoidal Salmonella in Good Agricultural Practice Certified Broiler Farms and Poultry Slaughterhouses in an Intensive Farming Area in Upper Northern Part of Thailand

Non-typhoidal Salmonella (NTS) is still one of the most infectious foodborne pathogens causing problematic health issues worldwide in both human and veterinary medicine. Poultry meat was one of the important sources of NTS spreading and tended to be highly resistant to antibiotics. The aim of this study was to determine the prevalence, serotypes, and antimicrobial-resistant patterns of Salmonella circulating in broiler farms and poultry slaughterhouses in an intensive farming area in the upper northern part of Thailand from August to October 2019. Fifty samples of boot swabs were collected from 50 broiler farms, 50 cecal samples, and 250 neck skin samples from slaughterhouses. Salmonella was identified by culture method and serum-agglutination and antimicrobial susceptibility testing was tested using the automated VITEK-2 compact system. This study's total prevalence of Salmonella was 53.71% (n=188/350). We found that 53% (159/300) of cecal and neck skins samples were collected from slaughterhouses and 58% (29/50) of boot swabs collected from broiler farms were positive for NTS. Twenty-four serotypes of NTS were identified, the most encountered was S. Kentucky. The antimicrobial-resistant patterns showed that all the strains were non-susceptible to amikacin, cefalexin, cephalothin, and gentamicin and were susceptible to imipenem, neomycin, and nitrofurantoin. The NTS prevalence in samples from broiler farms was slightly higher than in poultry slaughterhouses indicating that there was contamination in the farming and slaughtering process. Therefore, both hygienic measurements in poultry production and antimicrobial usage in the poultry industry should be considered.

Reduced immunogenicity of a live Salmonella enterica serovar Typhimurium vaccine in aged mice.

Non-typhoidal Salmonella (NTS) is responsible for a high burden of foodborne infections and deaths worldwide. In the United States, NTS infections are the leading cause of hospitalizations and deaths due to foodborne illnesses, and older adults (≥65 years) are disproportionately affected by Salmonella infections. Due to this public health concern, we have developed a live attenuated vaccine, CVD 1926 (I77 ΔguaBA ΔclpP ΔpipA ΔhtrA), against Salmonella enterica serovar Typhimurium, a common serovar of NTS. Little is known about the effect of age on oral vaccine responses, and due to the decline in immune function with age, it is critical to evaluate vaccine candidates in older age groups during early product development. In this study, adult (six-to-eight-week-old) and aged (18-month-old) C57BL/6 mice received two doses of CVD 1926 (109 CFU/dose) or PBS perorally, and animals were evaluated for antibody and cell-mediated immune responses. A separate set of mice were immunized and then pre-treated with streptomycin and challenged orally with 108 CFU of wild-type S. Typhimurium SL1344 at 4 weeks postimmunization. Compared to PBS-immunized mice, adult mice immunized with CVD 1926 had significantly lower S. Typhimurium counts in the spleen, liver, and small intestine upon challenge. In contrast, there were no differences in bacterial loads in the tissues of vaccinated versus PBS aged mice. Aged mice exhibited reduced Salmonella-specific antibody titers in the serum and feces following immunization with CVD 1926 compared to adult mice. In terms of T cell responses (T-CMI), immunized adult mice showed an increase in the frequency of IFN-γ- and IL-2-producing splenic CD4 T cells, IFN-γ- and TNF-α-producing Peyer's Patch (PP)-derived CD4 T cells, and IFN-γ- and TNF-α-producing splenic CD8 T cells compared to adult mice administered PBS. In contrast, in aged mice, T-CMI responses were similar in vaccinated versus PBS mice. CVD 1926 elicited significantly more PP-derived multifunctional T cells in adult compared to aged mice. These data suggest that our candidate live attenuated S. Typhimurium vaccine, CVD 1926, may not be sufficiently protective or immunogenic in older humans and that mucosal responses to live-attenuated vaccines decrease with increasing age.

G Protein-Coupled Receptor 120 Mediates Host Defense against Clostridium perfringens Infection through Regulating NOD-like Receptor Family Pyrin Domain-Containing 3 Inflammasome Activation.

Clostridium perfringens is a major cause of infectious foodborne disease, frequently associated with the consumption of raw and undercooked food. Despite intensive studies on clarifying C. perfringens pathogenesis, the molecular mechanisms of host-pathogen interactions remain poorly understood. In soft tissue and mucosal infection models, Gpr120-/- mice, G protein-coupled receptor 120 (GPR120), are more susceptible to C. perfringens infection. Gpr120 deficiency leads to a low survival rate (30 and 10%, p < 0.01), more bacterial loads in the muscle (2.26 × 108 ± 2.08 × 108 CFUs/g, p < 0.01), duodenum (2.80 × 107 ± 1.61 × 107 CFUs/g, p < 0.01), cecum (2.50 × 108 ± 2.05 × 108 CFUs/g, p < 0.01), and MLN (1.23 × 106 ± 8.06 × 105 CFUs/g, p < 0.01), less IL-18 production in the muscle (8.54 × 103 ± 1.20 × 103 pg/g, p < 0.01), duodenum (3.34 × 103 ± 2.46 × 102 pg/g, p < 0.01), and cecum (3.81 × 103 ± 5.29 × 102 pg/g, p < 0.01), and severe organ injury. Obviously, GPR120 facilitates IL-18 production and pathogen control via potassium efflux-dependent NOD-like receptor family pyrin domain-containing 3 (NLRP3) signaling. Mechanistically, GPR120 interaction with NLRP3 potentiates the NLRP3 inflammasome assembly. Thus, this study uncovers a novel role of GPR120 in host protection and reveals that GPR120 may be a potential therapeutic target for limiting pathogen infection.

Antimicrobial activities of untreated and grape vinegar treated selected vegetables against common food borne pathogens

In the post-Covid-19 era, plant-based diets and products have become more popular. Fruit vinegar is considered a healthy drink, rich in bioactive compounds like organic acids, polyphenols, flavonoids and alkaloids that provide several beneficial properties. Fruit vinegar also contains several beneficial nutrients like amino acids, sugars, vitamins and minerals. They provide energy, regulate cell metabolism, immunity, antioxidation, anticoagulation and help in the improvement of brain development. Vinegar is also known for its strong antimicrobial properties against foodborne pathogens. The aim of the present investigation was to find out the antimicrobial activities of grape vinegar against common food-borne pathogens and to see whether common vegetable lose their antimicrobial activities when soaked with grape vinegar or gain. The vegetables used in the present investigation were randomly collected from the local market. We have evaluated the antimicrobial properties of untreated and grape vinegar (GV) treated selected vegetables against Escherichia coli (ATCC8739), Bacillus subtilis, Staphylococcus aureus (ATCC 6539), Shigella flexneri (ATCC 12022), Salmonella typhi (ATCC 14028), Cronobacter sakazakii (ATCC 29544), Vibrio parahaemolyticus (ATCC 17802), Vibrio cholera (ATCC 3906) and Pseudomonas aeruginosa. Based on the randomized survey, commonly used vegetable ginger (Zingiber officinale), garlic (Allium sativum), onion (Allium cepa), raw papaya (Carica papaya), white radish (Raphanus sativus) and green chilli (Capsicum annuum) were selected for the assessment of their antimicrobial activities. Different phytochemicals were found in water extract and grape vinegar-treated vegetables. Our results suggested that in general, grape vinegar-treated vegetables showed higher antimicrobial activities against all tested food-borne pathogens, but onion, garlic, green chillies and white radish revealed drastically higher activities. Hence, it is suggested that onion, garlic, green chillies and white radish should preferably be used after soaking with grape vinegar. All vegetables except garlic and white radish showed very little antimicrobial activity against B. subtilis. V. cholera was highly sensitive to grape vinegar-treated vegetables except for garlic. Similarly, V. parahaemolyticus was highly sensitive to grape vinegar-treated green chillies, white radish, raw papaya, and onion. Shigella flexneri also showed greater sensitivity to GV-treated green chillies and white radishes. Pseudomonas aeruginosa was sensitive to ginger and green chillies only. It may safely be concluded that grape vinegar-treated vegetables are beneficial to fight against food-borne infections. The vegetable when soaked with grape vinegar did not lose their antimicrobial activities rather they gained the antimicrobial components from grape vinegar. Our studies revealed that white radish, ginger, green chilies, and onion should be used after soaking in grape vinegar while garlic and raw papaya should be eaten without treatment with grape vinegar.

Characterization of ready-to-eat fish surface as a potential source of contamination of Vibrio parahaemolyticus biofilms

The worldwide consumption of ready-to-eat seafood products has steadily increased due to a range of health benefits. However, depending on the handling or cutting process of raw fish, ready-to-eat sashimi can be exposed to microbiological risks that can lead to foodborne infection by marine pathogens. Since surface characteristics are key factors for microbial adhesion and biofilm formation, the present study aims to determine the correlation between raw fish skin properties and Vibrio parahaemolyticus biofilm formation. We analyzed V. parahaemolyticus biofilms (ATCC 17802; initially inoculated ca. 2 or 4 log CFU/cm2) on fish skin (gizzard shad, pomfret, red snapper, and mackerel; fish species served as sashimi without peeling the skin) formed under simulated marine environments (incubating in artificial seawater with rocking motion at 30 °C, the maximum temperature of seasonal seawater) for 24 h. The characteristics of fish skin were determined using confocal laser scanning microscopy/scanning electron microscopy. V. parahaemolyticus showed higher biofilm counts on fish skins than on stainless steel, which was used as a control (P < 0.05). In particular, V. parahaemolyticus formed biofilms with significantly higher levels of bacterial populations on gizzard shad and pomfret (ca. 5 log CFU/cm2; P < 0.05), highlighting the relationship between the biofilm formation level and the characteristics of gizzard shad and pomfret skins. The surface roughness of fish skins, including the main roughness parameters (Ra, Rq, and Rz), influenced the attachment of V. parahaemolyticus (P < 0.05). Additionally, images of V. parahaemolyticus biofilms suggested that different topographical profiles of fish species (e.g., mucus, unique structural features, etc.) could cause V. parahaemolyticus to exhibit different biofilm phenotypes, such as sticking to or entangling on the fish skin surface. The major findings of this study provide various phenotypic adhesions of V. parahaemolyticus to fish skin in considerations of the potential hazard for the consumption of ready-to-eat sashimi served with its skin.

Serotype distribution, trend of multidrug resistance and prevalence of β-lactamase resistance genes in human Salmonella isolates from clinical specimens in Guizhou, China.

Salmonella, one of the major causes of foodborne infections, can cause bacterial foodborne illness. We investigated the serotype distribution, multidrug resistance (MDR), and β-lactamase resistance genes of human Salmonella isolates collected from clinical specimens in Guizhou, China, between 2013 and 2018. A total of 363 Salmonella isolates were collected from clinical specimens at 17 surveillance hospitals. Twenty-four serotypes were identified by sliding agglutination test. S. Enteritidis (33.9%), Salmonella 4,[5],12:i:- (24.0%), S. Typhimurium (16.3%), S. London (6.3%), and S. Derby (3.9%) were the top five serotypes. In 2018, the most common serotype changed from S. Enteritidis to S. Typhimurium. Among the 363 Salmonella isolates, 97.5% of isolates were resistant to at least one class of antimicrobial agents. For cephalosporins, ceftriaxone had the highest resistance rate of 10.5%, and cefepime and cefoxitin were 8.0% and 2.2%, respectively. Three hundred and one (82.9%) Salmonella isolates showed MDR. Salmonella 4,[5],12:i:- had the highest MDR rate with 94.2%, followed by S. London (91.3%) and S. Typhimurium (88.1%). Multidrug resistance rates of Salmonella isolates in Guizhou from 2013 to 2017 increased from 75.8% to 86.7%. Sixteen isolates (4.4%) showed extensive drug resistance. One hundred thirty-four antimicrobial resistance patterns were found. Two hundred and forty-one (66.4%) isolates carried at least one β-lactamase resistance gene. The blaTEM gene (61.2%) was the most prevalent resistant gene in all Salmonella isolates, followed by the blaCTX-M gene (6.1%) and blaOXA-1 gene (4.1%). Our findings showed that the MDR rate of Salmonella isolates from Guizhou province increased year by year. Therefore, systematic and long-term surveillance on MDR Salmonella isolates from clinical patients should be further strengthened.

Public health issues related to poultry and poultry products

Several factors are influencing the poultry production and health such as strong global competition; changes in social, political and consumer perceptions with regard to food safety, animal welfare and environmental protection.&#x0D; The loss of consumer confidence and trust in the quality and safety of poultry meat and poultry products will remain a continuous major challenge. Many human foodborne infections are linked to poultry. Control and/or elimination of these organisms present a great challenge.&#x0D; The development of antibiotic resistant bacteria will also be a continuous public health hazard. The future concept of animal health will cover not only the absence of disease in birds, but also the relationship between the health of animals and their welfare. It will also take into account social, economic and ethical considerations, as well as support the achievement of a high level of environmental protection. In general, consumer expectations for high quality products will strongly influence future production methods. This means that farmers, veterinarians, stockholders and all other partners involved in the production chain need to share more responsibilities. The present paper explores these points.

Assessment of stn, sipB and sopB virulence genes in various Salmonella serovars

Salmonella is a zoonotic bacterium that is considered to be one of the most common causes of foodborne infections worldwide. Bearing in mind the genes involved in its virulence, identifying these genes can enable experts to better understand bacterial pathogenicity, which could subsequently help develop more efficient means to control and prevent infections. This study aimed to analyze stn, sipB, and sopB genes in various Salmonella serovars. To carry out this study, 103 Salmonella serovars were extracted from livestock, poultry, and humans from existing samples at the Department of Microbiology of the Razi Serum and Vaccine Research Institute in Karaj, Iran. These samples were cultured in selection and differential media, and their serovars were identified using specific antibodies based on Kaufman-White Tables. Utilizing PCR and specific primers, stn, sopB, and sipB genes were detected among these serovars. In this investigation, the most common human serovars were Salmonella paratyphi A, Salmonella paratyphi B, and Salmonella enteritidis; the most common serovars among livestock consisted of Salmonella dublin and Salmonella typhimurium and the most common Salmonella serovars among poultry consisted of Salmonella infantis and Salmonella enteritidis. The results of PCR on stn, sipB, and sopB genes demonstrated segments with 617bp, 875 bp, and 220 bp on agar gel, respectively. Based on the obtained findings, stn, sipB, and sopB genes were detected in 96.11%, 99.02%, and 98.05% of Salmonella serovars, respectively. Considering the fact that the aforementioned genes play significant roles in bacterial virulence, they can be used to develop diagnostic ELISA kits and recombinant vaccines.

Application of a novel lytic Jerseyvirus phage LPSent1 for the biological control of the multidrug-resistant Salmonella Enteritidis in foods.

Non-typhoidal Salmonella is the tremendously predominant source of acquired foodborne infection in humans, causing salmonellosis which is a global threat to the healthcare system. This threat is even worse when it is combined with the incidence of multidrug-resistant Salmonella strains. Bacteriophage therapy has been proposed as a promising potential candidate to control a diversity of foodborne infective bacteria. The objective of this study designed to isolate and characterize lytic phages infecting zoonotic multi-drug resistant and strong biofilm producer Salmonella enterica serovar Enteritidis EG.SmE1 and then apply the isolated phage/s as a biocontrol agent against infections in ready-to-eat food articles including milk, water, apple juice, and chicken breasts. One lytic phage (LPSent1) was selected based on its robust and stable lytic activity. Phage LPSent1 belonged to the genus Jerseyvirus within the Jerseyvirinae subfamily. The lysis time of phage LPSent1 was 60 min with a latent period of 30 min and each infected cell burst about 112 plaque-forming units. Phage LPSent1 showed a narrow host range. Furthermore, the LPSent1 genome did not encode any virulence or lysogenic genes. In addition, phage LPSent1 had wide pH tolerance, prolonged thermal stability, and was stable in food articles lacking its susceptible host for 48 h. In vitro applications of phage LPSent1 inhibited free planktonic cells and biofilms of Salmonella Enteritidis EG.SmE1 with a lower occurrence to form phage-resistant bacterial mutants which suggests promising applications on food articles. Application of phage LPSent1 at multiplicities of infections of 100 or 1000 showed significant inhibition in the bacterial count of Salmonella Enteritidis EG.SmE1 by 5 log10/sample in milk, water, apple juice, and chicken breasts at either 4°C or 25°C. Accordingly, taken together these findings establish phage LPSent1 as an effective, promising candidate for the biocontrol of MDR Salmonella Enteritidis in ready-to-eat food.

Decreased immunoreactivity of hepatitis E virus antigen following treatment with Sakhalin spruce (Picea glehnii) essential oil.

The hepatitis E virus (HEV) causes a common infectious disease that infects pigs, wild boars, deer, and humans. In most cases, humans are infected by eating raw meat. Some essential oils have been reported to exhibit antiviral activities. In this study, in order to investigate the anti-HEV properties of essential oils, the immunoreactivities of HEV antigen proteins against the relevant antibodies were analyzed after the HEV antigens underwent treatment with various essential oils. The essential oils extracted from the tea tree, which was previously reported to exhibit antiviral activity, lavender, and lemon had strongly reduced activity. We found that treatment with the essential oil prepared from Sakhalin spruce was associated with the strongest reduction in immunoreactivity of HEV antigen protein(s) among the tested substances. The main volatile constituents of Sakhalin spruce essential oil were found to be bornyl acetate (32.30%), α-pinene (16.66%), camphene (11.14%), camphor (5.52%), β-phellandrene (9.09%), borneol (4.77%), and limonene (4.57%). The anti-HEV properties of the various components of the essential oils were examined: treatment with bornyl acetate, the main component of Sakhalin spruce oil, a-pinene, the main component of tea tree oil, and limonene, the main component of lemon oil, resulted in a strong reduction in HEV antigen immunoreactivity. These results indicate that each main component of the essential oils plays an important role in the reduction of the immunoreactivity of HEV antigen protein(s); they also suggest that Sakhalin spruce essential oil exhibits anti-HEV activity. In a formulation with the potential to eliminate the infectivity of HEV in foodborne infections, this essential oil can be applied as an inactivating agent for meat processing and cooking utensils, such as knives and chopping boards.

PREVALENCE OF SALMONELLA AND INTESTINAL PARASITES AMONG FOOD HANDLERS PREDISPOSE CONSUMERS TO SIGNIFICANT HEALTH RISKS

Background and objectives: Food borne diseases are a global public health problem and food handlers play a major role for the transmission of food borne diseases. This study was aimed at exploring the prevalence of intestinal parasites, Salmonella typhi carrier rate and risk factors of infection with typhoid and/or intestinal parasites among food handlers at Ibb city, Yemen. Subjects and methods: A cross sectional survey was conducted among three hundred and fifteen food handlers, in age ranges from 14 to 65 years. All individuals were working in restaurants, cafeterias or school buffets in Ibb city. For collecting data; a pre-tested structured questionnaire was used. Stool samples were examined for intestinal parasites microscopy and for S. typhi by stool culture media and blood for detection antibodies per the standard laboratory methods were used. Results: A total of 315 food handlers in Ibb city over a 12-month period were enrolled in this study, ages ranged from 14 to 65 years, with a mean±SD age of 31.2±11.9 years. The highest prevalence of antibodies against S. typhi antigen suspension O was 18.4%, while antibodies against S. typhi H antigen suspension were 7.6%. Also, the positive rate for total S. typhi antibodies ELISA IgG was 9.5% and the positive rate for S. typhi stool cultures was 7.3%. The overall prevalence of intestinal protozoa was 20%, the most intestinal parasitic prevalent was Entamoeba histolytica (15.6%), followed by Ascaris lumbricoides (12.1%), Hymenolepis nana (4.4%), and Schistosoma mansoni (3.2%). Conclusion: Inexperienced and poor personal hygienic food handlers play a role in the transmission of food-borne infections. Local health authorities should implement food handlers training on food safety, institute periodic focused medical check-up for food handlers and improve human waste disposal. Peer Review History: Received: 4 January 2023; Revised: 13 February; Accepted: 8 March 2023, Available online: 15 March 2023 Academic Editor: Dr. A.A. Mgbahurike, University of Port Harcourt, Nigeria, amaka_mgbahurike@yahoo.com Received file: Reviewer's Comments: Average Peer review marks at initial stage: 5.5/10 Average Peer review marks at publication stage: 7.0/10 Reviewers: Rola Jadallah, Arab American University, Palestine, rola@aauj.edu Dr. Tamer Elhabibi, Suez Canal University, Egypt, tamer_hassan@pharm.suez.edu.eg Dr. Wadhah Hassan Ali Edrees, Hajja University, Yemen, edress2020@gmail.com Dr. Rawaa Souhil Al-Kayali, Aleppo University, Syria, rawah67@hotmail.com Similar Articles: EVALUATION OF ANTIBACTERIAL RESISTANCE OF BIOFILM FORMS OF AVIAN SALMONELLA GALLINARUM TO FLUOROQUINOLONES

Egress of Listeria monocytogenes from Mesenteric Lymph Nodes Depends on Intracellular Replication and Cell-to-Cell Spread.

The mesenteric lymph nodes (MLN) function as a barrier to systemic spread for both commensal and pathogenic bacteria in the gut. Listeria monocytogenes, a facultative intracellular foodborne pathogen, readily overcomes this barrier and spreads into the bloodstream, causing life-threatening systemic infections. We show here that intracellular replication protected L. monocytogenes from clearance by monocytes and neutrophils and promoted colonization of the small intestine-draining MLN (sMLN) but was not required for dissemination to the colon-draining MLN (cMLN). Intestinal tissue had enough free lipoate to support LplA2-dependent extracellular growth of L. monocytogenes, but exogenous lipoate in the MLN was severely limited, and so the bacteria could replicate only inside cells, where they used LplA1 to scavenge lipoate from host peptides. When foodborne infection was manipulated to allow ΔlplA1 L. monocytogenes to colonize the MLN to the same extent as wild-type bacteria, the mutant was still never recovered in the spleen or liver of any animal. We found that intracellular replication in the MLN promoted actin-based motility and cell-to-cell spread of L. monocytogenes and that rapid efficient exit from the MLN was actA dependent. We conclude that intracellular replication of L. monocytogenes in intestinal tissues is not essential and serves primarily to amplify bacterial burdens above a critical threshold needed to efficiently colonize the cMLN. In contrast, intracellular replication in the MLN is absolutely required for further systemic spread and serves primarily to promote ActA-mediated cell-to-cell spread.