Optical sensing for real-time detection of food-borne pathogens in fresh produce using machine learning.

Contaminated fresh produce remains a prominent catalyst for food-borne illnesses, prompting the need for swift and precise pathogen detection to mitigate health risks. This paper introduces an innovative strategy for identifying food-borne pathogens in fresh produce samples from local markets and grocery stores, utilizing optical sensing and machine learning. The core of our approach is a photonics-based sensor system, which instantaneously generates optical signals to detect pathogen presence. Machine learning algorithms process the copious sensor data to predict contamination probabilities in real time. Our study reveals compelling results, affirming the efficacy of our method in identifying prevalent food-borne pathogens, including Escherichia coli (E. coli) and Salmonella enteric, across diverse fresh produce samples. The outcomes underline our approach's precision, achieving detection accuracies of up to 95%, surpassing traditional, time-consuming, and less accurate methods. Our method's key advantages encompass real-time capabilities, heightened accuracy, and cost-effectiveness, facilitating its adoption by both food industry stakeholders and regulatory bodies for quality assurance and safety oversight. Implementation holds the potential to elevate food safety and reduce wastage. Our research signifies a substantial stride toward the development of a dependable, real-time food safety monitoring system for fresh produce. Future research endeavors will be dedicated to optimizing system performance, crafting portable field sensors, and broadening pathogen detection capabilities. This novel approach promises substantial enhancements in food safety and public health.

A population-based study of the appearances of enteric Campylobacter and non-typhoidal Salmonella infections on computed tomography.

BACKGROUND: Swift identification and diagnosis of gastrointestinal infections are crucial for prompt treatment, prevention of complications, and reduction of the risk of hospital transmission. The radiological appearance on computed tomography could potentially provide important clues to the etiology of gastrointestinal infections. We aimed to describe features based on computed tomography of patients diagnosed with Campylobacter, Salmonella or Shigella infections in South Sweden. METHODS: This was a retrospective observational population-based cohort study conducted between 2019 and 2022 in Skåne, southern Sweden, a region populated by 1.4 million people. Using data from the Department of Clinical Microbiology combined with data from the Department of Radiology, we identified all patients who underwent computed tomography of the abdomen CTA two days before and up to seven days after sampling due to the suspicion of Campylobacter, Salmonella or Shigella during the study period. RESULTS: A total of 215 CTAs scans performed on 213 patients during the study period were included in the study. The median age of included patients was 45 years (range 11-86 years), and 54% (114/213) of the patients were women. Of the 215 CTAs, 80% (n = 172) had been performed due to Campylobacter and 20% (n = 43) due to Salmonella enteritis. CTA was not performed for any individual diagnosed with Shigella during the study period. There were no statistically significant differences in the radiological presentation of Campylobacter and Salmonella infections. CONCLUSION: The most common location of Campylobacter and Salmonella infections was the cecum, followed by the ascending colon. Enteric wall edema, contrast loading of the affected mucosa, and enteric fat stranding are typical features of both infections. The CTA characteristics of Campylobacter and Salmonella are similar, and cannot be used to reliably differentiate between different infectious etiologies.

Multidrug resistance in Salmonella isolates of swine origin: mobile genetic elements and plasmids associated with cephalosporin resistance with potential transmission to humans.

The emergence of foodborne Salmonella strains carrying antimicrobial resistance (AMR) in mobile genetic elements (MGE) is a significant public health threat in a One Health context requiring continuous surveillance. Resistance to ciprofloxacin and cephalosporins is of particular concern. Since pigs are a relevant source of foodborne Salmonella for human beings, we studied transmissible AMR genes and MGE in a collection of 83 strains showing 9 different serovars and 15 patterns of multidrug resistant (MDR) previously isolated from pigs raised in the conventional breeding system of Northern Spain. All isolates were susceptible to ciprofloxacin and three isolates carried blaCMY-2 or blaCTX-M-9 genes responsible for cefotaxime resistance. Filter mating experiments showed that the two plasmids carrying blaCTX-M-9 were conjugative while that carrying blaCMY-2 was self-transmissible by transformation. Whole-genome sequencing and comparative analyses were performed on the isolates and plasmids. The IncC plasmid pSB109, carrying blaCMY-2, was similar to one found in S. Reading from cattle, indicating potential horizontal transfer between serovars and animal sources. The IncHI2 plasmids pSH102 in S. Heidelberg and pSTM45 in S. Typhimurium ST34, carrying blaCTX-M-9, shared similar backbones and two novel "complex class 1 integrons" containing different AMR and heavy metal genes. Our findings emphasize the importance of sequencing techniques to identify emerging AMR regions in conjugative and stable plasmids from livestock production. The presence of MGE carrying clinically relevant AMR genes raises public health concerns, requiring monitoring to mitigate the emergence of bacteria carrying AMR genes and subsequent spread through animals and food.IMPORTANCEThe emergence of foodborne Salmonella strains carrying antimicrobial resistance (AMR) in mobile genetic elements (MGE) is a significant public health threat in a One Health context. Since pigs are a relevant source of foodborne Salmonella for humans, in this study, we investigate different aspects of AMR in a collection of 83 Salmonella showing nine different serovars and 15 patterns of multidrug resistant (MDR) isolated from pigs raised in the conventional breeding system. Our findings emphasize the importance of sequencing techniques to identify emerging AMR regions in conjugative and stable plasmids from livestock production. The presence of MGE carrying clinically relevant AMR genes raises public health concerns, requiring monitoring to mitigate the emergence of bacteria carrying AMR genes and subsequent spread through animals and food.

Prevalence, associated factors and antimicrobial susceptibility patterns of Salmonella and Shigella species among diarrheic under five children in Sultan Sheik Hassan Yabere referral Hospital, Jigjiga, Eastern Ethiopia.

BACKGROUND: Diarrhea caused by Salmonella and Shigella species are the leading cause of illness especially in developing countries. These infections are considered as the main public health problems in children, including Ethiopia. This study aimed to assess the prevalence, associated factors, and antimicrobial susceptibility patterns of Salmonella and Shigella species in Sheik Hassan Yabere Referral Hospital Jigjiga, Eastern Ethiopia from August 05 to November 15, 2022. METHOD: A cross-sectional study was conducted among 239 under-five children with diarrhea selected through a convenient sampling technique. A structured questionnaire was used to collect associated factors. A stool sample was collected and processed for the identification of Salmonella and Shigella species using MacConkey adar, Xylose Lysine Deoxycholate agar (Oxoid Ltd) and Biochemical tests. The antimicrobial susceptibility pattern of isolates was performed using the Kirby-Bauer disc diffusion technique. The data was entered into Epi-data version 4.6 and exported to the statistical package of social science version 22 for analysis. The association between outcome and independent variables was assessed using bivariate, multivariable, and chi-square and P-value < 0.05 was considered as statistical significance. RESULT: Overall prevalence of Salmonella and Shigella species was 6.3% (95% CI, 5.7-6.9%), of which 3.8% (95 CI, 3.2-4.4%) were Salmonella species and 2.5% (95% CI, 1.95-3%) were Shigella species. Unimproved water source (AOR = 5.08, 95% CI = 1.45, 17.25), open field (AOR = 2.3, 95% CI = 1.3, 5.03), rural residence (AOR = 1.8, 95% CI = 1.4, 7.5), Hand-washing practice (p = 0.001), and raw meat consumption (p = 0.002) were associated with occurrence of Salmonella and Shigella species. Salmonella and Shigella isolates were resistant to Ampicilin (100%). However, Salmonella isolates was sensitive to Norfloxacin (100%). About 22.2% and 16.7% of Salmonella and Shigella isolates were multi-drug resistant, respectively. CONCLUSION: Prevalence of Salmonella and Shigella species were lower than most studies done in Ethiopia. Hand-washing habit, water source type, Open field waste disposal habit, raw meat consumption and rural residence were associated with Salmonellosis and shigellosis. All isolated Salmonella were sensitive to norfloxacin. The evidence from this study underscores the need for improved water, sanitation and hygiene (WASH) system and the imperative to implement drug susceptibility tests for the treatment of Salmonella and Shigella infection.

Prevalence of multidrug resistance Salmonella species isolated from clinical specimens at University of Gondar comprehensive specialized hospital Northwest Ethiopia: A retrospective study.

BACKGROUND: Multidrug resistance Salmonellosis remains an important public health problem globally. The disease is among the leading causes of morbidity and mortality in developing countries, but there have been limited recent studies about the prevalence, antimicrobial resistance, and multidrug resistance patterns of Salmonella isolates from various clinical specimens. OBJECTIVE: Aimed to assess the prevalence, antimicrobial resistance, and multidrug resistance patterns of Salmonella isolates from clinical specimens at the University of Gondar Comprehensive Specialised Hospital, northwestern Ethiopia. METHOD: A retrospective hospital-based cross-sectional study was conducted to determine the prevalence, antimicrobial resistance, and multidrug resistance patterns of isolated from all clinical specimens at the University of Gondar Salmonella Comprehensive Specialised Hospital from June 1st, 2017 to June 3rd, 2022. A total of 26,154 data points were collected using a checklist of records of laboratory registration. Clinical specimens were collected, inoculated, and incubated for about a week with visual inspection for growth and gram staining. The isolates were grown on MacConkey agar and Xylose Lysine Deoxycholate agar. Pure colonies were identified with a conventional biochemical test, and those unidentified at the species level were further identified by the analytical profile index-20E. Then, antimicrobial susceptibility was determined by the Kirby-Bauer disc diffusion technique. The multidrug resistance Salmonella isolates was identified using the criteria set by Magiorakos. Finally, the data was cleaned and checked for completeness and then entered into SPSS version 26 for analysis. Then the results were displayed using tables and figures. RESULTS: Of the total 26,154 Salmonella suspected clinical samples, 41 (0.16%) Salmonella species were isolated. Most of the Salmonella isolates, 19 (46.3%), were in the age group of less than 18 years, followed by the age group of 19-44 years, 11 (26.8%). In this study, S. enterica subsp. arizonae accounts for the highest 21 (51%), followed by S. paratyphi A 9 (22%). Of the Salmonella isolates, S. typhi were highly resistant to ampicillin (100%), followed by tetracycline and trimethoprim-sulfamethoxazole, each accounting for 83.3%. Furthermore, S. paratyphi A was resistant to ampicillin (100%), tetracycline (88.9%), and chloramphenicol (88.9%). The overall multi-drug resistance prevalence was 22 (53.7%; 95% CI: 39.7-61). Accordingly, S. paratyphi A was 100% multidrug-resistant, followed by S. typhi (66.6%). CONCLUSION: A low prevalence of Salmonella species was observed in the past six years. Moreover, most S. typhi and S. paratyphi strains in the study area were found to be resistant to routinely recommended antibiotics like ciprofloxacin and ceftriaxone, compared to what was reported earlier. In addition, all isolates of S. paratyphi A and the majority of S. typhi were multidrug resistant. Therefore, health professionals should consider antimicrobial susceptibility tests and use antibiotics with caution for Salmonellosis management.

Raw meat-based diet for pets: a neglected source of human exposure to Salmonella and pathogenic Escherichia coli clones carrying mcr, Portugal, September 2019 to January 2020.

BackgroundThe pet industry is expanding worldwide, particularly raw meat-based diets (RMBDs). There are concerns regarding the safety of RMBDs, especially their potential to spread clinically relevant antibiotic-resistant bacteria or zoonotic pathogens.AimWe aimed to investigate whether dog food, including RMBD, commercially available in Portugal can be a source of Salmonella and/or other Enterobacteriaceae strains resistant to last-line antibiotics such as colistin.MethodsFifty-five samples from 25 brands (21 international ones) of various dog food types from 12 suppliers were screened by standard cultural methods between September 2019 and January 2020. Isolates were characterised by phenotypic and genotypic methods, including whole genome sequencing and comparative genomics.ResultsOnly RMBD batches were contaminated, with 10 of 14 containing polyclonal multidrug-resistant (MDR) Escherichia coli and one MDR Salmonella. One turkey-based sample contained MDR Salmonella serotype 1,4,[5],12:i:- ST34/cgST142761 with similarity to human clinical isolates occurring worldwide. This Salmonella exhibited typical antibiotic resistance (bla TEM + strA-strB + sul2 + tet(B)) and metal tolerance profiles (pco + sil + ars) associated with the European epidemic clone. Two samples (turkey/veal) carried globally dispersed MDR E. coli (ST3997-complexST10/cgST95899 and ST297/cgST138377) with colistin resistance (minimum inhibitory concentration: 4 mg/L) and mcr-1 gene on IncX4 plasmids, which were identical to other IncX4 circulating worldwide.ConclusionSome RMBDs from European brands available in Portugal can be a vehicle for clinically relevant MDR Salmonella and pathogenic E. coli clones carrying genes encoding resistance to the last-line antibiotic colistin. Proactive actions within the One Health context, spanning regulatory, pet-food industry and consumer levels, are needed to mitigate these public health risks.

Antimicrobial resistance and genetic relatedness of Salmonella serotypes isolated from food, asymptomatic carriers, and clinical cases in Shiyan, China.

Salmonella is a primary cause of foodborne diseases globally. Despite food contamination and clinical infections garnering substantial attention and research, asymptomatic Salmonella carriers, potential sources of infection, have been comparatively overlooked. In this study, we conducted a comparative analysis of serotype distribution, antimicrobial resistance phenotypes, and genetic profiles of archived Salmonella strains isolated from food (26), asymptomatic carriers (41), and clinical cases (47) in Shiyan City, China. Among the 114 Salmonella strains identified, representing 31 serotypes and 34 Sequence Types (STs), the most prevalent serovars included Typhimurium, Derby, Enteritidis, Thompson, and London, with the most predominant STs being ST11, ST40, ST26, ST34, and ST155. Antimicrobial resistance testing revealed that all strains were only sensitive to meropenem, with 74.6% showing antimicrobial resistance (AMR) and 53.5% demonstrating multidrug resistance (MDR). Strains resistant to five and six classes of antibiotics were the most common. Pearson's chi-square test showed no statistically significant difference in the occurrence of AMR (p = 0.105) or MDR (p = 0.326) among Salmonella isolates from the three sources. Our findings underscore associations and diversities among Salmonella strains isolated from food, asymptomatic carriers, and clinical patients, emphasizing the need for increased vigilance towards asymptomatic Salmonella carriers by authorities.

Salmonella Saintpaul outbreak associated with cantaloupe consumption, the United Kingdom and Portugal, September to November 2023.

In September 2023, the UK Health Security Agency identified cases of Salmonella Saintpaul distributed across England, Scotland, and Wales, all with very low genetic diversity. Additional cases were identified in Portugal following an alert raised by the United Kingdom. Ninety-eight cases with a similar genetic sequence were identified, 93 in the United Kingdom and 5 in Portugal, of which 46% were aged under 10 years. Cases formed a phylogenetic cluster with a maximum distance of six single nucleotide polymorphisms (SNPs) and average of less than one SNP between isolates. An outbreak investigation was undertaken, including a case-control study. Among the 25 UK cases included in this study, 13 reported blood in stool and 5 were hospitalized. One hundred controls were recruited via a market research panel using frequency matching for age. Multivariable logistic regression analysis of food exposures in cases and controls identified a strong association with cantaloupe consumption (adjusted odds ratio: 14.22; 95% confidence interval: 2.83-71.43; p-value: 0.001). This outbreak, together with other recent national and international incidents, points to an increase in identifications of large outbreaks of Salmonella linked to melon consumption. We recommend detailed questioning and triangulation of information sources to delineate consumption of specific fruit varieties during Salmonella outbreaks.

Prevalence of Salmonella spp., Shigella spp., and intestinal parasites among food handlers working in University of Gondar student's cafeteria, Northwest Ethiopia.

Background: Food-borne infections continue to be a major public health problem at the international level. The issue becomes more serious in developing countries like Ethiopia. Objective: This study aimed to examine the prevalence of Salmonella and Shigella species and intestinal parasites, as well as antimicrobial resistance patterns and associated factors among food handlers at the University of Gondar cafeteria in northwest Ethiopia. Methods: An institutional-based cross-sectional study was conducted from February to June 2021 in the University of Gondar cafeterias. Data related to the socio-demographic characteristics and hygienic practices of study participants were collected using structured questionnaires. A total of 290 stool samples were collected from food handlers. Culture and conventional biochemical tests were used to isolate the Salmonella and the Shigella species. Wet mount, Formol-ether concentration, and Kato Katz techniques were applied to identify intestinal parasites. Additionally, drug susceptibility tests were performed using the disk diffusion method. Statistical analysis was done using SPSS version 26. Results: Of 290 food handlers' stool samples analyzed, Twenty-seven 27 (9.3%) were positive for both Salmonella and Shigella species. The prevalence of Salmonella and Shigella species was 16 (5.5%) and 11 (3.8%), respectively. Most of the isolated pathogens were resistant to tetracycline 19 (70.4%), and trimethoprim/sulphamethoxazole 19 (70.4%). The overall rate of multi-drug resistant Shigella and Salmonella isolate was 59.3%. Besides, Fifty-seven 57 (19.7%) of the participants were positive for one or more intestinal parasites. The most prevalent intestinal Parasitosis was E. histolytica/dispar 22 (7.6%), followed by G. lamblia 13 (4.5%), and Ascaris lumbricoides 11 (3.8) not washing hands after using the toilet (AOR: 4.42, 95% CI: 1.57, 10.56), and consuming unpasteurized milk (AOR: 3.14, 95% CI: 1.65, 3.96), were factors significantly associated with the prevalence of Salmonella, and Shigella infection. Similarly, not washing hands after using the toilet (AOR: 2.19, 95% CI: 1.0, 1.4), and consuming unpasteurized milk (AOR: 10.4, 95% CI: 3.8, 28.8), were factors significantly associated with the prevalence of intestinal parasites infection. Conclusion: The prevalence of intestinal parasites, Salmonella, and Shigella species was high. Therefore, it is imperative to implement a public health policy that includes ongoing microbiological surveillance.

An analysis of culture-based methods used for the detection and isolation of Salmonella spp., Escherichia coli, and Enterococcus spp. from surface water: A systematic review.

Identification of methods for the standardized assessment of bacterial pathogens and antimicrobial resistance (AMR) in environmental water can improve the quality of monitoring and data collected, support global surveillance efforts, and enhance the understanding of environmental water sources. We conducted a systematic review to assemble and synthesize available literature that identified methods for assessment of prevalence and abundance of bacterial fecal indicators and pathogens in water for the purposes of monitoring bacterial pathogens and AMR. After screening for quality, 175 unique publications were identified from 15 databases, and data were extracted for analysis. This review identifies the most common and robust methods, and media used to isolate target organisms from surface water sources, summarizes methodological trends, and recognizes knowledge gaps. The information presented in this review will be useful when establishing standardized methods for monitoring bacterial pathogens and AMR in water in the United States and globally.

Microbiological quality of irrigation water on highly diverse fresh produce smallholder farms: elucidating environmental routes of contamination.

AIM: To evaluate the microbiological safety, potential multidrug-resistant bacterial presence and genetic relatedness (DNA fingerprints) of Escherichia coli isolated from the water-soil-plant nexus on highly diverse fresh produce smallholder farms. METHODS AND RESULTS: Irrigation water (n = 44), soil (n = 85), and fresh produce (n = 95) samples from six smallholder farms with different production systems were analysed for hygiene indicator bacterial counts and the presence of shigatoxigenic E. coli and Salmonella spp. using standard microbiological methods. Identities of isolates were confirmed using matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS), and the genetic relatedness of the E. coli isolates determined using enterobacterial repetitive intergenic consensus polymerase chain reaction (ERIC-PCR) analysis. Irrigation water E. coli levels ranged between 0 and 3.45 log MPN/100 ml-1 with five farms having acceptable levels according to the World Health Organization limit (3 log MPN/100 ml-1). Fresh produce samples on four farms (n = 65) harboured E. coli at low levels (<1 log CFU/g-1) except for one sample from kale, spring onion, green pepper, onion, and two tomato samples, which exceeded international acceptable limits (100 CFU/g-1). Only one baby carrot fresh produce sample tested positive for Salmonella spp. Of the 224 samples, E. coli isolates were identified in 40% (n = 90) of all water, soil, and fresh produce types after enrichment. Additionally, the DNA fingerprints of E. coli isolates from the water-soil-plant nexus of each respective farm clustered together at high similarity values (>90%), with all phenotypically characterized as multidrug-resistant. CONCLUSIONS: The clustering of E. coli isolated throughout the water-soil-plant nexus, implicated irrigation water in fresh produce contamination. Highlighting the importance of complying with irrigation water microbiological quality guidelines to limit the spread of potential foodborne pathogens throughout the fresh produce supply chain.

Effect of combined infection with Salmonella and influenza virus on their respective proliferation in chicken embryonated eggs.

Background: Salmonella is a major food-borne bacterial pathogen that causes food poisoning related to the consumption of eggs, milk, and meat. Food safety in relation to Salmonella is particularly important for eggs because their shells as well as their contents can be a source of contamination. Chicken can also be infected with influenza virus, but it remains unclear how co-infection of Salmonella and influenza virus affect each other. Aim: The potential influence of co-infection of Salmonella and influenza virus was examined. Methods: Salmonella Abony and influenza virus were injected into chicken embryonated eggs. After incubation, proliferation of Salmonella and influenza virus was measured using a direct culture assay for bacteria and an enzyme-linked immunosorbent assay for influenza virus, respectively. Results: Our findings indicate that the number of colony-forming units (CFUs) of Salmonella did not vary between chicken embryonated eggs co-infected with influenza A virus and Salmonella-only infected eggs. Furthermore, we found the proliferation of influenza A or B virus was not significantly influenced by co-infection of the eggs with Salmonella. Conclusion: These results suggest that combined infection of Salmonella with influenza virus does not affect each other, at least in terms of their proliferation.

[Etiological characterization of invasive non-typhoid Salmonella strains in Guangdong Province from 2018 to 2022].

Objective: To understand the serotype distribution, drug resistance and molecular characterization of invasive non-typhoid Salmonella (iNTS) in Guangdong Province from 2018 to 2022 and provide scientific evidence for the prevention and treatment of blood flow infection caused by Salmonella. Methods: Serological identification, antimicrobial susceptibility testing, multilocus sequence typing (MLST), and whole genome sequencing were performed on Salmonella isolated from blood and stool samples in Guangdong from 2018 to 2022. Simultaneously, annotated the sequencing results for drug resistance genes and virulence factors by a microbial gene annotation system. Results: The 136 iNTS strains were divided into 25 serotypes, and Salmonella enteritidis accounted for 38.24% (52/136). The OR of other iNTS serotypes were calculated with Salmonella typhimurium as the control. The OR values of Oreninburg, Rysson, and Pomona serotypes were the highest, which were 423.50, 352.92, and 211.75, respectively. The drug resistance rate of iNTS was 0.74%-66.91%, which was lower than that of non-iNTS (3.90%-77.21%). The main iNTS of drug resistance were ampicillin and tetracycline, with resistance rates of 66.91% (91/136) and 50.00% (68/136), respectively, while the resistance rates to ciprofloxacin (5.88%,8/136), ceftazidime (5.88%,8/136), gentamicin (5.13%,7/136) and cefoxitin (0.74%, 1/136) were relatively low. iNTS carried a variety of drug-resistance genes and virulence factors, but no standard virulence factor distribution has been found. MLST cluster analysis showed that iNTS was divided into 26 sequence types, and ST11 accounted for 38.24% (52/136). Conclusions: The iNTS strains in Guangdong were dominated by Salmonella enteritidis, of which three serotypes, Oreninburg, Rison, and Pomona, may be associated with a higher risk of invasive infection during 2018 to 2022. iNTS was sensitive to clinical first-line therapeutic drugs (cephalosporins and fluoroquinolones), with highly diverse sequences and clear phylogenetic branches. ST11 was the local dominant clone group.

Recombinase polymerase amplification combined with Pyrococcus furiosus Argonaute for fast Salmonella spp. testing in food safety.

Foodborne illness caused by Salmonella spp. is one of the most prevalent public health problems globally, which have brought immeasurable economic burden and social impact to countries around the world. Neither current nucleic acid amplification detection method nor standard culture method (2-3 days) are suitable for field detection in areas with a heavy burden of Salmonella spp. Here, we developed a highly sensitive and accurate assay for Salmonella spp. detection in less than 40 min. Specifically, the invA gene of Salmonella spp. was amplified by recombinase polymerase amplification (RPA), followed by Pyrococcus furiosus Argonaute (PfAgo)-based target sequence cleavage, which could be observed by a fluorescence reader or the naked eye. The assay offered the lowest detectable concentration of 1.05 × 101 colony forming units/mL (CFU/mL). This assay had strong specificity and high sensitivity for the detection of Salmonella spp. in field samples, which indicated the feasibility of this assay.

Genomic analysis of Salmonella isolated from canal water in Bangkok, Thailand.

Antimicrobial resistance (AMR) poses an escalating global public health threat. Canals are essential in Thailand, including the capital city, Bangkok, as agricultural and daily water sources. However, the characteristic and antimicrobial-resistance properties of the bacteria in the urban canals have never been elucidated. This study employed whole genome sequencing to characterize 30 genomes of a causal pathogenic bacteria, Salmonella enterica, isolated from Bangkok canal water between 2016 and 2020. The dominant serotype was Salmonella Agona. In total, 35 AMR genes and 30 chromosomal-mediated gene mutations were identified, in which 21 strains carried both acquired genes and mutations associated with fluoroquinolone resistance. Virulence factors associated with invasion, adhesion, and survival during infection were detected in all study strains. 75.9% of the study stains were multidrug-resistant and all the strains harbored the necessary virulence factors associated with salmonellosis. One strain carried 20 resistance genes, including mcr-3.1, mutations in GyrA, ParC, and ParE, and typhoid toxin-associated genes. Fifteen plasmid replicon types were detected, with Col(pHAD28) being the most common type. Comparative analysis of nine S. Agona from Bangkok and 167 from public databases revealed that specific clonal lineages of S. Agona might have been circulating between canal water and food sources in Thailand and globally. These findings provide insight into potential pathogens in the aquatic ecosystem and support the inclusion of environmental samples into comprehensive AMR surveillance initiatives as part of a One Health approach. This approach aids in comprehending the rise and dissemination of AMR and devising sustainable intervention strategies.IMPORTANCEBangkok is the capital city of Thailand and home to a large canal network that serves the city in various ways. The presence of pathogenic and antimicrobial-resistant Salmonella is alarming and poses a significant public health risk. The present study is the first characterization of the genomic of Salmonella strains from Bangkok canal water. Twenty-two of 29 strains (75.9%) were multidrug-resistant Salmonella and all the strains carried essential virulence factors for pathogenesis. Various plasmid types were identified in these strains, potentially facilitating the horizontal transfer of AMR genes. Additional investigations indicated a potential circulation of S. Agona between canal water and food sources in Thailand. The current study underscores the role of environmental water in an urban city as a reservoir of pathogens and these data obtained can serve as a basis for public health risk assessment and help shape intervention strategies to combat AMR challenges in Thailand.

Multiplex nanozymatic biosensing of Salmonella on a finger-actuated microfluidic chip.

A colorimetric biosensor was elaboratively designed for fast, sensitive and multiplex bacterial detection on a single microfluidic chip using immune magnetic nanobeads for specific bacterial separation, immune gold@platinum palladium nanoparticles for specific bacterial labeling, a finger-actuated mixer for efficient immunoreaction and two coaxial rotatable magnetic fields for magnetic nanobead capture (outer one) and magnet-actuated valve control (inner one). First, preloaded bacteria, nanobeads and nanozymes were mixed through a finger actuator to form nanobead-bacteria-nanozyme conjugates, which were captured by the outer magnetic field. After the inner magnetic field was rotated to successively wash the conjugates and push the H2O2-TMB substrate for resuspending these conjugates, colorless TMB was catalyzed into blue TMBox products, followed by color analysis using ImageJ software for bacterial determination. This simple biosensor enabled multiplex Salmonella detection as low as 9 CFU per sample in 45 min.

Factors Associated with the Prevalence of Salmonella, Generic Escherichia coli, and Coliforms in Florida's Agricultural Soils.

Limited data exist on the environmental factors that impact pathogen prevalence in the soil. The prevalence of foodborne pathogens, Salmonella and Listeria monocytogenes, and the prevalence and concentration of generic E. coli in Florida's agricultural soils were evaluated to understand the potential risk of microbial contamination at the preharvest level. For all organisms but L. monocytogenes, a longitudinal field study was performed in three geographically distributed agricultural areas across Florida. At each location, 20 unique 5 by 5 m field sampling sites were selected, and soil was collected and evaluated for Salmonella presence (25 g) and E. coli and coliform concentrations (5 g). Complementary data collected from October 2021 to April 2022 included: weather; adjacent land use; soil properties, including macro- and micro-nutrients; and field management practices. The overall Salmonella and generic E. coli prevalence was 0.418% (1/239) and 11.3% (27/239), respectively; with mean E. coli concentrations in positive samples of 1.56 log CFU/g. Farm A had the highest prevalence of generic E. coli, 22.8% (18/79); followed by Farm B, 10% (8/80); and Farm C 1.25% (1/80). A significant relationship (p < 0.05) was observed between generic E. coli and coliforms, and farm and sampling trip. Variation in the prevalence of generic E. coli and changes in coliform concentrations between farms suggest environmental factors (e.g. soil properties) at the three farms were different. While Salmonella was only detected once, generic E. coli was detected in Florida soils throughout the duration of the growing season meaning activities that limit contact between soil and horticultural crops should continue to be emphasized. Samples collected during an independent sampling trip were evaluated for L. monocytogenes, which was not detected. The influence of local environmental factors on the prevalence of indicator organisms in the soil presents a unique challenge when evaluating the applicability of more global models to predict pathogen prevalence in preharvest produce environments.

Microbial profile of broiler carcasses processed at a university scale mobile poultry processing unit.

Chicken and chicken products have been associated with foodborne pathogens such as Salmonella, Campylobacter, and Escherichia coli (E. coli). Poultry comprises an important segment of the agricultural economy (75 million birds processed as of 2019) in West Virginia (WV). The risk of pathogens on processed chickens has risen with the increased popularity of mobile poultry processing units (MPPUs). This study evaluated the microbial safety of broilers processed in a MPPU in WV. This study assessed aerobic plate counts (APCs), E. coli counts and the presence/absence of Salmonella and Campylobacter on 96 broiler carcasses following each MPPU step of scalding, eviscerating, and chilling. Samples were either chilled in ice water only (W) or ice water with 5 ppm chlorine (CW). The highest number of bacteria recovered from carcasses were APCs (4.21 log10CFU/mL) and E. coli (3.77 log10CFU/mL; P = 0.02). A total reduction of 0.30 (P = 0.10) and 0.63 (P = 0.01) log10CFU/mL for APCs and E. coli, respectively, occurred from chilling carcasses in CW. Overall, results show that E. coli, Salmonella, and Campylobacter were significantly (P < 0.05) reduced from the initial scalding to the chilling step. However, Salmonella frequency doubled (15.63-34.38%) after the evisceration step, indicating that washing carcasses after evisceration may be a critical control point in preventing cross-contamination by Salmonella. Proper chilling is also an important microbial mitigation step in MPPU processing. Results indicate that Campylobacter was more resistant to chilling than Salmonella. Campylobacter was not completely inactivated until carcasses were chilled in CW, whereas W was sufficient to reduce Salmonella on carcasses. The results led to the conclusion that although 5 ppm chlorine (Cl2) achieved more bacterial reductions than water alone, the reductions were not always significant (P > 0.05). Further MPPU studies are needed to verify more effective chilling and processing strategies.

High Salmonella load with serovar virchow dominance pose major public safety risk in postchill broiler carcasses.

The objective of this study was to determine Salmonella contamination levels, presence and serovar distribution in broiler carcasses before and after chilling, as well as to evaluate the effectiveness of chilling process. A total of 96 pooled neck skin samples (PNSS) of 48 prechill (PreC) and 48 postchill (PosC) carcasses, representing 480 broilers collected in 6 mo' period were analyzed using ISO 6579-2:2012 Miniaturized Most Probable Number (ISO-mMPN) technique. Species confirmation and serovar identification was performed by Salmonella-specific real-time PCR (Salm-PCR) and conventional serotyping, respectively. Mean Salmonella count was 1.84 log10 MPN/g in PreC, and 1.48 log10 MPN/g in PosC samples, indicating a statistically significant reduction of 0.36 log10 MPN/g (p < 0.05) in the counts by plant's air chill system. Salmonella positivity reduced from 97.9% (47/48) in PreC to 85.42% (41/48) in PosC samples, confirmed by Salm-PCR with identified serovars as S. Virchow (89.77 %) followed by S. Schwarzengrund (9.09%) and S. Bredeney (1.14%). Persistence of high load and prevalence of Salmonella with serovar Virchow dominance (other than the ones mandated in current guidelines) in the final product contributes significant and up to date data to relevant literature, and provides unbiased epidemiological reference to legal authorities for future relevant revisions.