RESUMEN
Salmonella is a major bacterial concern for public health globally. Although there are limited documentation on the prevalence of Salmonella species in Cambodia's food chain, some reports indicate that salmonellosis is a severe gastrointestinal infection in its population and especially in children. To investigate the presence of Salmonella spp., 285 food samples (75 meat, 50 seafood, and 160 leafy green vegetable samples) were randomly collected from various local markets in Phnom Penh capital and nearby farms in Cambodia. Concurrently, field observations were conducted to collect data on food hygiene and practices among the relevant actors. All food samples were analyzed using bacterial culture and plate counts, and the findings were confirmed serially with biochemical, serological, and PCR tests. The observational data on food hygiene and practices from farm to market revealed that the spread of Salmonella in the food-value chain from farm to market could pose health risks to consumers. The overall prevalence of Salmonella spp. was 48.4% (138/285), while the prevalence in meat, seafood, and vegetables was 71% (53/75), 64% (32/50), and 33% (53/160), respectively. Mean Salmonella plate count ranged from 1.2 to 7.40 log10 CFU/g, and there was no significant difference in bacterial counts between meat, seafood, and vegetable samples (p > 0.05). The most common serogroups among the isolated Salmonella spp. were B and C. These results suggest that a large proportion of meat, seafood, and vegetable products sold at local markets in Phnom Penh are contaminated with Salmonella spp. This is likely linked to inadequate hygiene and sanitation practices, including handling, storage, and preservation conditions. Observations on farms suggested that the prevalence of Salmonella in vegetables sold at the market could be linked to contamination relating to agricultural practices. Thus, controlling the spread of foodborne salmonellosis through the food-value chain from farms and retailers to consumers is warranted to enhance food safety in Cambodia.
Asunto(s)
Granjas , Contaminación de Alimentos , Carne , Salmonella , Alimentos Marinos , Verduras , Cambodia/epidemiología , Verduras/microbiología , Salmonella/aislamiento & purificación , Salmonella/clasificación , Contaminación de Alimentos/análisis , Contaminación de Alimentos/estadística & datos numéricos , Prevalencia , Alimentos Marinos/microbiología , Carne/microbiología , Animales , Microbiología de Alimentos , Humanos , HigieneRESUMEN
Existing research has underscored the vital interplay between host organisms and their associated microbiomes, which affects health and function. In both plants and animals, host factors critically shape microbial communities and influence growth, health, and immunity. Post-harvest plants, such as those used in kimchi, a traditional Korean dish, offer a unique avenue for exploring host-microbe dynamics during fermentation. Despite the emphasis on lactic acid bacteria (LAB) in fermentation studies, the roles of host factors remain unclear. This study aimed to investigate the influence of these factors on plant transcriptomes during kimchi fermentation. We individually inoculated nine LAB strains into germ-free kimchi to generate LAB-mono-associated gnotobiotic kimchi and performed RNA-sequencing analysis for the host vegetables during fermentation. The transcriptomes of post-harvest vegetables in kimchi change over time, and microbes affect the transcriptome profiles of vegetables. Differentially expressed gene analyses revealed that microbes affected the temporal expression profiles of several genes in the plant transcriptomes in unique directions depending on the introduced LAB strains. Cluster analysis with other publicly available transcriptomes of post-harvest vegetables and fruits further revealed that the plant transcriptome is more profoundly influenced by the environment harboring the host than by host phylogeny. Our results bridge the gap in understanding the bidirectional relationship between host vegetables and microbes during food fermentation, illuminating the complex interplay between vegetable transcriptomes, fermentative microbes, and the fermentation process in food production. The different transcriptomic responses elicited by specific LAB strains suggest the possibility of microbial manipulation to achieve the desired fermentation outcomes.
Asunto(s)
Fermentación , Vida Libre de Gérmenes , Verduras , Verduras/genética , Verduras/microbiología , Transcriptoma/genética , Alimentos Fermentados/microbiología , Regulación de la Expresión Génica de las Plantas , Lactobacillales/genética , Lactobacillales/fisiología , Lactobacillales/metabolismoRESUMEN
Recent advancements in modeling suggest that microbial inactivation in leafy greens follows a nonlinear pattern, rather than the simple first-order kinetics. In this study, we evaluated 17 inactivation models commonly used to describe microbial decline and established the conditions that govern microbial survival on leafy greens. Through a systematic review of 65 articles, we extracted 530 datasets to model the fate of Shiga toxin-producing Escherichia coli O157:H7 on leafy greens. Various factor analysis methods were employed to evaluate the impact of identified conditions on survival metrics. A two-parameter model (jm2) provided the best fit to most of both natural and antimicrobial-induced persistence datasets, whereas the one-parameter exponential model provided the best fit to less than 20% of the datasets. The jm2 model (adjusted R2 = .89) also outperformed the exponential model (adjusted R2 = .58) in fitting the pooled microbial survival data. In the context of survival metrics, the model averaging approach generated higher values than the exponential model for >4 log reduction times (LRTs), suggesting that the exponential model may be overpredicting inactivation at later time points. The random forest technique revealed that temperature and inoculum size were common factors determining inactivation in both natural and antimicrobial-induced die-offs.. The findings show the limitations of relying on the first-order survival metric of 1 LRT and considering nonlinear inactivation in produce safety decision-making.
Asunto(s)
Escherichia coli O157 , Escherichia coli O157/efectos de los fármacos , Microbiología de Alimentos , Verduras/microbiología , Viabilidad Microbiana , Hojas de la Planta/microbiología , Hojas de la Planta/químicaRESUMEN
The accuracy of predictive microbial models used in quantitative microbial risk assessment (QMRA) relies on the relevancy of conditions influencing growth or inactivation. The continued use of log-linear models in studies remains widespread, despite evidence that they fail to accurately account for biphasic kinetics or include parameters to account for the effect of environmental conditions within the model equation. Although many experimental studies detail conditions of interest, studies that do not do so lead to uncertainty in QMRA modeling because the applicability of the predictive microbial models to the conditions in the risk scenarios is questionable or must be extrapolated. The current study systematically reviewed 65 articles that provided quantitative data and documented the conditions influencing the inactivation or growth of Shiga toxin-producing Escherichia coli (STEC) O157:H7 in leafy greens. The conditions were identified and categorized as environmental, biological, chemical, and/or processing. Our study found that temperature (n = 37 studies) and sanitizing and washing procedures (n = 12 studies) were the most studied conditions in the farm-to-table continuum of leafy greens. In addition, relative humidity was also established to affect growth and inactivation in more than one stage in the continuum. This study proposes the evaluation of the interactive effects of multiple conditions in processing and storage stages from controlled experiments as they relate to the fate of STEC O157:H7 in leafy greens for future quantitative analysis.
Asunto(s)
Escherichia coli O157 , Escherichia coli O157/crecimiento & desarrollo , Microbiología de Alimentos , Temperatura , Verduras/microbiología , Manipulación de Alimentos/métodos , Medición de Riesgo , Escherichia coli Shiga-Toxigénica/crecimiento & desarrollo , Escherichia coli Shiga-Toxigénica/fisiologíaRESUMEN
The resistance of foodborne pathogens to antimicrobial agents is a potential danger to human health. Hence, establishing the status of good agricultural practices (GAPs) and the antimicrobial susceptibility of major foodborne pathogens has a significant programmatic implication in planning interventions. The objective of this study was to assess the gap in attaining GAP and estimate the prevalence and antimicrobial susceptibility profile of Salmonella in vegetable farms fertilized with animal manure in Addis Ababa, Ethiopia. A total of 81 vegetable farms from four sub-cities in Addis Ababa were visited, and 1119 samples were collected: soil (n = 271), manure (n = 375), vegetables (n = 398), and dairy cattle feces (n = 75). Additional data were collected using a structured questionnaire. Isolation of Salmonella was done using standard microbiology techniques and antimicrobial susceptibility testing was conducted using disk diffusion assays. Carriage for antimicrobial resistance genes was tested using polymerase chain reaction (PCR). Among the 81 vegetable farms visited, 24.7% used animal manure without any treatment, 27.2% used properly stored animal manure and 80.2% were easily accessible to animals. The prevalence of Salmonella was 2.3% at the sample level, 17.3% at the vegetable farm level, and 2.5% in vegetables. The highest rate of resistance was recorded for streptomycin, 80.7% (21 of 26), followed by kanamycin, 65.4% (17 of 26), and gentamicin, 61.5% (16 of 26). Multidrug resistance was detected in 61.5% of the Salmonella isolates. Vegetable farms have a gap in attaining GAPs, which could contribute to increased contamination and the transfer of antimicrobial resistance to the vegetables. The application of GAPs, including proper preparation of compost and the appropriate use of antimicrobials in veterinary practices, are recommended to reduce the emergence and spread of antimicrobial resistance.
Asunto(s)
Antibacterianos , Granjas , Estiércol , Salmonella , Verduras , Etiopía/epidemiología , Animales , Salmonella/aislamiento & purificación , Salmonella/efectos de los fármacos , Salmonella/genética , Verduras/microbiología , Estiércol/microbiología , Prevalencia , Bovinos , Antibacterianos/farmacología , Pruebas de Sensibilidad Microbiana , Fertilizantes , Microbiología del Suelo , Farmacorresistencia Bacteriana , Humanos , Heces/microbiología , AgriculturaRESUMEN
The ability of foodborne pathogens to grow in food products increases the associated food safety risks. Listeria monocytogenes (Lm) is a highly adaptable pathogen that can survive and grow under a wide range of environmental circumstances, including otherwise inhibitory conditions, such as restrictive cold temperatures. It can also survive long periods under adverse environmental conditions. This review examines the experimental evidence available for the survival and growth of Lm on fresh vegetables and ready-to-eat vegetable salads. Published data indicate that, depending on certain intrinsic (e.g., nutrient composition) and extrinsic factors (e.g., storage temperature, packaging atmosphere), Lm can survive on and in a wide variety of vegetables and fresh-cut minimally processed vegetable salads. Studies have shown that temperature, modified atmosphere packaging, relative humidity, pH, water activity, background microbiota of vegetables, microbial strain peculiarities, and nutrient type and availability can significantly impact the fate of Lm in vegetables and vegetable salads. The influence of these factors can either promote its growth or decline. For example, some studies have shown that background microbiota inhibit the growth of Lm in vegetables and minimally processed vegetable salads, but others have reported a promoting, neutral, or insignificant effect on the growth of Lm. A review of relevant literature also indicated that the impact of most influencing factors is related to or interacts with other intrinsic or extrinsic factors. This literature synthesis contributes to the body of knowledge on possible strategies for improving food safety measures to minimize the risk of Lm-associated foodborne outbreaks involving vegetables and vegetable salads.
Asunto(s)
Microbiología de Alimentos , Listeria monocytogenes , Verduras , Listeria monocytogenes/crecimiento & desarrollo , Verduras/microbiología , Productos Vegetales/microbiología , Temperatura , Ensaladas/microbiología , Contaminación de Alimentos/prevención & control , Contaminación de Alimentos/análisisRESUMEN
BACKGROUND: Food-associated antibiotic-resistant bacteria can cause infections that may critically impact human health. The objectives of this study were to determine the microbial contamination level of green leafy vegetables and their antibiotic resistance pattern. METHODS: Sixty-three samples of leafy vegetables were collected from Dammam Central Fruit and Vegetables Market from January to June 2023. The vegetables included lettuce (Lactuca sativa), parsley (Petroselinum crispum), and watercress (Nasturtium officinale). Samples were tested by standard microbiological techniques for identification and antibiotic susceptibility testing. RESULT: Eight types of bacteria belonging to six different genera were detected. Enterobacteriaceae family was represented by four genera: Klebsiella, Proteus, Morganella, and Enterobacter. The other two genera were Pseudomonas and Aeromonas. Enterobacter cloacae was the most abundant organism, followed by Pseudomonas putida and Aeromonas sobria. On the other hand, Morganella morganii, Aeromonas hydrophila, and Proteus mirabilis were the least abundant. The three vegetable types had different levels of bacterial contamination. All isolated organisms were sensitive to penicillin, cephalosporin, aminoglycoside, and fluoroquinolone. However, Klebsiella oxytoca, M. morganii, and K. pneumonia showed resistance to ampicillin. A. hydrophila, Morganella morganii, and E. cloacae showed resistance to amoxicillin. M. morganii and E. cloacae were found to be resistant to cefalotin. Moreover, A. hydrophila, M. morganii, and E. cloacae were resistant to cefoxitin. Again, A. hydrophila was found to be resistant to imipenem. Only M. morganii was resistant to Ciprofloxacin. Two isolates, P. mirabilis and M. morganii were resistant to tigecycline. Another two, M. morganii and P. mirabilis were resistant to Nitrofurantoin. Only M. morganii was found to be resistant to trimethoprim. CONCLUSION: This study aligns with the broad consensus in the literature about the significance of bacterial contamination in vegetables and the public health implications. The unique focus on antibiotic resistance patterns adds an essential dimension to the existing body of knowledge.
Asunto(s)
Antibacterianos , Bacterias , Farmacorresistencia Bacteriana , Pruebas de Sensibilidad Microbiana , Verduras , Arabia Saudita , Verduras/microbiología , Antibacterianos/farmacología , Bacterias/efectos de los fármacos , Bacterias/aislamiento & purificación , Bacterias/clasificación , Bacterias/genética , Lactuca/microbiología , Microbiología de Alimentos , Hojas de la Planta/microbiología , Petroselinum/microbiología , Enterobacteriaceae/efectos de los fármacos , Enterobacteriaceae/aislamiento & purificación , Enterobacteriaceae/clasificación , Contaminación de Alimentos/análisisRESUMEN
This research presents a comprehensive review of Salmonella presence in retail fresh fruits and vegetables from 2010 to 2023, utilizing data from recognized sources such as PubMed, Scopus, and Web of Science. The study incorporates a meta-analysis of prevalence, serovar distribution, antimicrobial susceptibility, and antimicrobial resistance genes (ARGs). Additionally, it scrutinizes the heterogeneous sources across various food categories and geographical regions The findings show a pooled prevalence of 2.90% (95% CI: 0.0180-0.0430), with an increase from 4.63% in 2010 to 5.32% in 2022. Dominant serovars include S. Typhimurium (29.14%, 95% CI: 0.0202-0.6571) and S. Enteritidis (21.06%, 95% CI: 0.0181-0.4872). High resistance rates were noted for antimicrobials like erythromycin (60.70%, 95% CI: 0.0000-1.0000) and amoxicillin (39.92%, 95% CI: 0.0589-0.8020). The most prevalent ARGs were blaTEM (80.23%, 95% CI: 0.5736-0.9692) and parC mutation (66.67%, 95% CI: 0.3213-0.9429). Factors such as pH, water activity, and nutrient content, along with external factors like the quality of irrigation water and prevailing climatic conditions, have significant implications on Salmonella contamination. Nonthermal sterilization technologies, encompassing chlorine dioxide, ozone, and ultraviolet light, are emphasized as efficacious measures to control Salmonella. This review stresses the imperative need to bolster prevention strategies and control measures against Salmonella in retail fresh fruits and vegetables to alleviate related food safety risks.
Asunto(s)
Frutas , Salmonella , Serogrupo , Verduras , Verduras/microbiología , Frutas/microbiología , Salmonella/efectos de los fármacos , Salmonella/aislamiento & purificación , Salmonella/genética , Prevalencia , Antibacterianos/farmacología , Farmacorresistencia Bacteriana , Contaminación de Alimentos/análisis , Microbiología de AlimentosRESUMEN
Tigecycline serves as a last-resort antimicrobial agent against severe infections caused by multidrug-resistant bacteria. Tet(X) and its numerous variants encoding flavin-dependent monooxygenase can confer resistance to tigecycline, with tet(X4) being the most prevalent variant. This study aims to investigate the prevalence and characterize tigecycline resistance gene tet(X) in E. coli isolates from various origins in Yangzhou, China, to provide insights into tet(X) dissemination in this region. In 2022, we tested the presence of tet(X) in 618 E. coli isolates collected from diverse sources, including patients, pig-related samples, chicken-related samples, and vegetables in Yangzhou, China. The antimicrobial susceptibility of tet(X)-positive E. coli isolates was conducted using the agar dilution method or the broth microdilution method. Whole genome sequencing was performed on tet(X)-positive strains using Illumina and Oxford Nanopore platforms. Four isolates from pig or pork samples carried tet(X4) and exhibited resistance to multiple antimicrobial agents, including tigecycline. They were classified as ST542, ST10, ST761, and ST48, respectively. The tet(X4) gene was located on IncFIA8-IncHI1/ST17 (n=2), IncFIA18-IncFIB(K)-IncX1 (n=1), and IncX1 (n=1) plasmids, respectively. These tet(X4)-carrying plasmids exhibited high similarity to other tet(X4)-bearing plasmids with the same incompatible types found in diverse sources in China. They shared related genetic environments of tet(X4) associated with ISCR2, as observed in the first identified tet(X4)-bearing plasmid p47EC. In conclusion, although a low prevalence (0.65%) of tet(X) in E. coli strains was observed in this study, the horizontal transfer of tet(X4) among E. coli isolates mediated by pandemic plasmids and the mobile element ISCR2 raises great concerns. Thus, heightened surveillance and immediate action are imperative to curb this clinically significant resistance gene and preserve the efficacy of tigecycline.
Asunto(s)
Antibacterianos , Infecciones por Escherichia coli , Escherichia coli , Pruebas de Sensibilidad Microbiana , Tigeciclina , Tigeciclina/farmacología , Escherichia coli/genética , Escherichia coli/efectos de los fármacos , Escherichia coli/aislamiento & purificación , China , Antibacterianos/farmacología , Porcinos , Animales , Infecciones por Escherichia coli/microbiología , Humanos , Plásmidos/genética , Pollos/microbiología , Secuenciación Completa del Genoma , Farmacorresistencia Bacteriana Múltiple/genética , Verduras/microbiología , Proteínas de Escherichia coli/genéticaRESUMEN
Bacteriophages (phages) have gained considerable attention as effective antimicrobial agents that infect and kill pathogenic bacteria. Based on this feature, phages have been increasingly used to achieve food safety. They are stored in a medium or buffer to ensure stability; however, they cannot be directly applied to food under these conditions due to reasons such as regulatory considerations and concerns about marketability. This study developed a stabilizing solution that allowed the maintenance of phage activity for extended periods at room temperature while being directly applicable to food. The stability of phages stored in distilled water was relatively low. However, adding a stabilizer composed of sugars and salts improved the survival rates of phages significantly, resulting in stability for up to 48 weeks at room temperature. When Escherichia coli O157:H7-contaminated vegetables were washed with tap water containing phages, the phages reduced the pathogenic E. coli count by over 90% compared with washing with tap water alone. Additionally, when pathogenic E. coli-contaminated vegetables were placed in a phage-coated container and exposed to water, the coating of the container dissolved, releasing phages and lysing the pathogenic E. coli. This led to a significant 90% reduction in pathogenic E. coli contamination compared to that after water rinsing. These results suggest an effective and economical method for maintaining phage activity and establishing the potential for commercialization through application in the food industry.
Asunto(s)
Bacteriófagos , Escherichia coli O157 , Microbiología de Alimentos , Temperatura , Verduras , Bacteriófagos/fisiología , Verduras/microbiología , Verduras/virología , Escherichia coli O157/virología , Enfermedades Transmitidas por los Alimentos/prevención & control , Enfermedades Transmitidas por los Alimentos/microbiología , Inocuidad de los AlimentosRESUMEN
The continuous detection of multi-drug-resistant enterococci in food source environments has aroused widespread concern. In this study, 198 samples from chicken products, animal feces, raw milk, and vegetables were collected in Japan and Egypt to investigate the prevalence of enterococci and virulence characterization. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was employed for species identification and taxonomic analysis of the isolates. The results showed that the rates of most virulence genes (efaA, gelE, asa1, ace, and hyl) in the Japanese isolates were slightly higher than those in the Egyptian isolates. The rate of efaA was the highest (94.9 %) among seven virulence genes detected, but the cylA gene was not detected in all isolates, which was in accordance with γ-type hemolysis phenotype. In Enterococcus faecalis, the rate of kanamycin-resistant strains was the highest (84.75 %) among the antibiotics tested. Moreover, 78 % of E. faecalis strains exhibited multi-drug resistance. Four moderately vancomycin-resistant strains were found in Egyptian isolates, but none were found in Japanese isolates. MALDI-TOF MS analysis correctly identified 98.5 % (68/69) of the Enterococcus isolates. In the principal component analysis dendrogram, strains isolated from the same region with the same virulence characteristics and similar biofilm-forming abilities were characterized by clustered distribution in different clusters. This finding highlights the potential of MALDI-TOF MS for classifying E. faecalis strains from food sources.
Asunto(s)
Antibacterianos , Biopelículas , Enterococcus , Microbiología de Alimentos , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Factores de Virulencia , Biopelículas/crecimiento & desarrollo , Enterococcus/genética , Enterococcus/patogenicidad , Enterococcus/efectos de los fármacos , Enterococcus/aislamiento & purificación , Factores de Virulencia/genética , Animales , Egipto , Antibacterianos/farmacología , Verduras/microbiología , Japón , Pollos , Leche/microbiología , Heces/microbiología , Pruebas de Sensibilidad Microbiana , Farmacorresistencia Bacteriana , Farmacorresistencia Bacteriana Múltiple , Contaminación de Alimentos/análisisRESUMEN
Infants have digestive environments that are more favorable for microbial proliferation and subsequent endogenous nitrite production than those of adults, but direct evidence of this has been lacking. In this study, we propose a novel epidemiology of infant methemoglobinemia by demonstrating the risk posed by nitrite-producers in the gastrointestinal tract. Nitrite-producers from vegetables (n = 323) were exposed to stress factors of the gastrointestinal environment (gastric pH, intestinal bile salts, anaerobic atmosphere) reflecting 4 different postnatal age periods (Neonate, ≤1 month; Infant A, 1-3 months; Infant B, 3-6 months; Infant C, 6-12 months). "High-risk" strains with a nitrate-to-nitrite conversion rate of ≥1.3 %, the minimum rate corresponding to nitrite overproduction, under the Neonate stress condition were analyzed for intestinal adhesion. Among all the phyla, Pseudomonadota achieved the highest survival (P < 0.05; survival rate of 51.3-71.8 %). Possible cross-protection against bile resistance due to acid shock was observed for all the phyla. All the high-risk strains exhibited moderate autoaggregation (14.0-36.4 %), whereas only a few exhibited satisfactory surface hydrophobicity (>40 %). The Pantoea agglomerans strain strongly adhered to Caco-2 cells (7.4 ± 1.1 %). This study showed the ability of the Pantoea, Enterobacter, and Klebsiella strains to survive under gastrointestinal stress for ≤12 months, to excessively produce nitrite under neonatal stress conditions, and to settle in the human intestine. To our knowledge, this is the first study to reveal the role of the natural flora of vegetables in the epidemiology of infant methemoglobinemia through a multilateral approach.
Asunto(s)
Metahemoglobinemia , Nitritos , Verduras , Humanos , Verduras/microbiología , Lactante , Metahemoglobinemia/metabolismo , Nitritos/metabolismo , Recién Nacido , Adhesión Bacteriana , Ácidos y Sales Biliares/metabolismo , Tracto Gastrointestinal/microbiología , Tracto Gastrointestinal/metabolismo , Concentración de Iones de Hidrógeno , Microbioma GastrointestinalRESUMEN
Pre-cut fresh fruits and vegetables are highly appealing to consumers for their convenience, however, as they are highly susceptible to microbial contamination in processing, the potential risks of foodborne illnesses to public health are not negligible. This study aimed to assess the prevalence, antibiotic susceptibility and molecular characteristics of major foodborne pathogens (Listeria monocytogenes, Escherichia coli, Staphylococcus aureus and Salmonella) isolated from fresh-cut fruits and vegetables in Beijing, China. 86 stains were isolated from 326 samples, with S. aureus being the highest prevalence (15.38 %), followed by E. coli (9.23 %) and L. monocytogenes (1.85 %), while no Salmonella was detected. The prevalence by type of food indicated that fruit trays and mixed vegetables were more susceptible to contamination by pathogens. 98 % of S. aureus were resistant to at least of one antibiotic, and showed a high resistance rate to benzylpenicillin (90 %) and oxacillin (48 %). Among 25 E. coli isolates, 57.67 % of which exhibited multi-drug resistance, with common resist to trimethoprim/sulfamethoxazole (66.67 %) and ampicillin (63.33 %). A total of 9 sequence types (STs) and 8 spa types were identified in 35 S. aureus isolates, with ST398-t34 being the predominant type (42.86 %). Additionally, analysis of 25 E. coli isolates demonstrated significant heterogeneity, characterized by 22 serotypes and 18 STs. Genomic analysis revealed that 5 and 44 distinct antibiotic resistance genes (ARGs) in S. aureus and E. coli, respectively. Seven quinolone resistance-determining regions (QRDRs) mutations were identified in E. coli isolates, of which GyrA (S83L) was the most frequently detected. All the S. aureus and E. coli isolates harbored virulence genes. ARGs in S. aureus and E. coli showed a significant positive correlation with plasmids. Furthermore, one L. monocytogenes isolate, which was ST101 and serogroupIIc from watermelon sample, harbored virulence genes (inlA and inlB) and LIPI-1 pathogenic islands (prfA, plcA, hly and actA), which posed potential risks for consumer's health. This study focused on the potential microbial risk of fresh-cut fruits and vegetables associated with foodborne diseases, improving the scientific understanding towards risk assessment related to ready-to-eat foods.
Asunto(s)
Antibacterianos , Escherichia coli , Microbiología de Alimentos , Frutas , Pruebas de Sensibilidad Microbiana , Staphylococcus aureus , Verduras , Verduras/microbiología , Frutas/microbiología , Staphylococcus aureus/genética , Staphylococcus aureus/aislamiento & purificación , Staphylococcus aureus/efectos de los fármacos , Antibacterianos/farmacología , Escherichia coli/aislamiento & purificación , Escherichia coli/genética , Escherichia coli/efectos de los fármacos , Beijing/epidemiología , Salmonella/genética , Salmonella/aislamiento & purificación , Salmonella/clasificación , Salmonella/efectos de los fármacos , Prevalencia , Contaminación de Alimentos/análisis , China/epidemiología , Listeria monocytogenes/genética , Listeria monocytogenes/aislamiento & purificación , Listeria monocytogenes/clasificación , Listeria monocytogenes/efectos de los fármacos , Farmacorresistencia Bacteriana/genética , Farmacorresistencia Bacteriana Múltiple/genética , Enfermedades Transmitidas por los Alimentos/microbiología , Enfermedades Transmitidas por los Alimentos/epidemiologíaRESUMEN
The presence of extended-spectrum beta-lactamase (ESBL)-producing Klebsiella pneumoniae in fresh fruits and vegetables is a growing public health concern. The primary objective of this study was to investigate the relationship between biofilm formation and extended-spectrum ß-lactamase (ESBL) production in K. pneumoniae strains obtained from fresh fruits and vegetables. Out of 120 samples analysed, 94 samples (78%) were found to be positive for K. pneumoniae. Among the K. pneumoniae strains isolated, 74.5% were from vegetables, whereas the remaining (25.5%) were from fresh fruits. K. pneumoniae isolates were resistant to at least three different classes of antibiotics, with ceftazidime (90%) and cefotaxime (70%) showing the highest resistance rates. While the high occurrence of ESBL-producing and biofilm-forming K. pneumoniae strains were detected in vegetables (73.5% and 73.7%, respectively), considerable amounts of the same were also found in fresh fruits (26.5% and 26.3%, respectively). The results further showed a statistically significant (P < 0.001) association between biofilm formation and ESBL production in K. pneumoniae strains isolated from fresh fruits and vegetables. Furthermore, the majority (81%) of the ESBL-producing strains harbored the blaCTX-M gene, while a smaller proportion of strains carried the blaTEM gene (30%), blaSHV gene (11%) or blaOXA (8%). This study highlights the potential public health threat posed by K. pneumoniae in fresh fruits and vegetables and emphasizes the need for strict surveillance and control measures.
Asunto(s)
Antibacterianos , Biopelículas , Frutas , Klebsiella pneumoniae , Pruebas de Sensibilidad Microbiana , Verduras , beta-Lactamasas , Biopelículas/crecimiento & desarrollo , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/efectos de los fármacos , Klebsiella pneumoniae/aislamiento & purificación , Verduras/microbiología , beta-Lactamasas/genética , beta-Lactamasas/metabolismo , Frutas/microbiología , Antibacterianos/farmacologíaRESUMEN
Resistance to carbapenems emerged in clinical settings and has rapidly spread to other sectors, such as food and the environment, representing a One Health problem. In this regard, vegetables contaminated by critical priority pathogens have raised global concerns. Here, we have performed a whole-genome sequence-based analysis of extensively drug-resistant Klebsiella pneumoniae, Escherichia coli, and Pseudomonas aeruginosa strains isolated from cabbage, spinach, and lettuce, respectively. Genomic analysis revealed the emergence of international and high-risk clones belonging to ST340, ST155, and ST233, harboring a broad resistome to clinically important antimicrobials. In this context, K. pneumoniae, E. coli, and P. aeruginosa strains carried blaKPC-2, blaNDM-1, and blaVIM-2, respectively. The blaKPC-2 gene with a non-Tn4401 element (NTEKPC-Ic) was located on an IncX3-IncU plasmid, while the blaVIM-2 gene was associated with a Tn402-like class 1 integron, In559, on the chromosome. Curiously, the blaNDM-1 gene coexisted with the blaPER-2 gene on an IncC plasmid and the regions harboring both genes contained sequences of Tn3-like element ISKox2-like family transposase. Comparative genomic analysis showed interspecies and clonal transmission of carbapenemase-encoding genes at the human-animal-environmental interface. These findings raise a food safety alert about hospital-associated carbapenemase producers, supporting that fresh vegetables can act as a vehicle for the spread of high-risk clones.
Asunto(s)
Verduras , beta-Lactamasas , beta-Lactamasas/genética , beta-Lactamasas/metabolismo , Verduras/microbiología , Inocuidad de los Alimentos , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Antibacterianos/farmacología , Pseudomonas aeruginosa/genética , Pseudomonas aeruginosa/enzimología , Pseudomonas aeruginosa/aislamiento & purificación , Pseudomonas aeruginosa/efectos de los fármacos , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/aislamiento & purificación , Klebsiella pneumoniae/enzimología , Klebsiella pneumoniae/efectos de los fármacos , Escherichia coli/genética , Escherichia coli/aislamiento & purificación , Escherichia coli/efectos de los fármacos , Escherichia coli/enzimología , Microbiología de Alimentos , Pruebas de Sensibilidad Microbiana , Farmacorresistencia Bacteriana Múltiple/genética , Plásmidos/genética , Secuenciación Completa del Genoma , HumanosRESUMEN
Challenge tests are commonly employed to evaluate the growth behavior of L. monocytogenes in food matrices; they are known for being expensive and time-consuming. An alternative could be the use of predictive models to forecast microbial behavior under different conditions. In this study, the growth behavior of L. monocytogenes in different fresh produce was evaluated using a predictive model based on the Gamma concept considering pH, water activity (aw), and temperature as input factors. An extensive literature search resulted in a total of 105 research articles selected to collect growth/no growth behavior data of L. monocytogenes. Up to 808 L. monocytogenes behavior values and physicochemical characteristics were extracted for different fruits and vegetables. The predictive performance of the model as a tool for identifying the produce commodities supporting the growth of L. monocytogenes was proved by comparing with the experimental data collected from the literature. The model provided satisfactory predictions on the behavior of L. monocytogenes in vegetables (>80% agreement with experimental observations). For leafy greens, a 90% agreement was achieved. In contrast, the performance of the Gamma model was less satisfactory for fruits, as it tends to overestimate the potential of acid commodities to inhibit the growth of L. monocytogenes.
Asunto(s)
Microbiología de Alimentos , Frutas , Listeria monocytogenes , Verduras , Listeria monocytogenes/crecimiento & desarrollo , Verduras/microbiología , Verduras/crecimiento & desarrollo , Frutas/microbiología , Concentración de Iones de Hidrógeno , Temperatura , Modelos Biológicos , Agua/metabolismo , Recuento de Colonia Microbiana , Contaminación de Alimentos/análisisRESUMEN
A key question in anaerobic microbial ecology is how microbial communities develop over different stages of waste decomposition and whether these changes are specific to waste types. We destructively sampled over time 26 replicate bioreactors cultivated on fruit/vegetable waste (FVW) and meat waste (MW) based on pre-defined waste components and composition. To characterize community shifts, we examined 16S rRNA genes from both the leachate and solid fractions of the waste. Waste decomposition occurred faster in FVW than MW, as accumulation of ammonia in MW reactors led to inhibition of methanogenesis. We identified population succession during different stages of waste decomposition and linked specific populations to different waste types. Community analyses revealed underrepresentation of methanogens in the leachate fractions, emphasizing the importance of consistent and representative sampling when characterizing microbial communities in solid waste.
Asunto(s)
Reactores Biológicos , ARN Ribosómico 16S , Reactores Biológicos/microbiología , Anaerobiosis , ARN Ribosómico 16S/genética , Eliminación de Residuos/métodos , Residuos Sólidos/análisis , Bacterias/metabolismo , Bacterias/genética , Bacterias/clasificación , Verduras/microbiología , Metano/metabolismo , Frutas/microbiología , Residuos de Alimentos , Alimento Perdido y DesperdiciadoRESUMEN
In vegetable fermentation, pellicle is a common quality deterioration phenomenon. This study investigates the characteristics of glucose, organic acids, amino acids, and biogenic amines during the pellicle occurrence and disappearance of paocai. The results revealed a slight increase in pH of the fermentation system after pellicle occurred, and glucose was the main carbohydrate that microbial activity primary relied on. The microorganisms responsible for pellicle formation consumed organic acids in brine, but the lactic acid in paocai gradually increased and exceeded 25 mg/g. The appearance of pellicle caused a decrease in total free amino acids from 200.390 mg/100 g to 172.079 when pellicle occurred, whereas its impact on biogenic amines was not apparent. Through Kyoto Encyclopedia of Genes and Genomes pathway enrichment of metagenomics sequencing data, screening, and sorting of the key enzymes involved in organic acid metabolism, it was observed that the composition and species of the key microorganisms capable of metabolizing organic acids were more abundant before the appearance of pellicle. When pellicle occurred, lactic acid may be metabolized by Lactobacillus plantarum; in contrast, Lactobacillus and Pichia were associated with citric acid metabolism, and Lactobacillus, Pichia, Saccharomycodes, and Kazachstania were linked to malic acid metabolism. Moreover, Prevotella, Kazachstania, Lactobacillus, Vibrio, and Siphonobacter were implicated in succinic acid metabolism. Additionally, the production of tartaric acid and oxalic acid in paocai and brine resulted from abiotic effects. This knowledge offers a theoretical basis for precise control of paocai fermentation process. PRACTICAL APPLICATION: Our study revealed the specific situation of the metabolites produced by the microorganisms during the pollution and recovery process of pellicle in paocai fermentation, especially the effect of pellicle on the key process of organic acid metabolism. These research results provided theoretical basis for precise control of paocai fermentation.
Asunto(s)
Aminoácidos , Fermentación , Ácido Láctico , Aminoácidos/metabolismo , Ácido Láctico/metabolismo , Bacterias/metabolismo , Bacterias/clasificación , Bacterias/genética , Ácido Cítrico/metabolismo , Concentración de Iones de Hidrógeno , Aminas Biogénicas/metabolismo , Aminas Biogénicas/análisis , Glucosa/metabolismo , Malatos/metabolismo , Microbiología de Alimentos , Alimentos Fermentados/microbiología , Verduras/microbiología , Sales (Química)RESUMEN
Temperature is an important driving force that shapes the texture of fermented vegetables through driving the molecular distribution and microbial invasion between the liquid phase (brine) and the solid phase (vegetables) during fermentation. The objective of this study was to investigate the texture softening by investigating firmness, microstructure, physicochemical properties, molecular distribution and microbial community between brine and vegetables of Paocai as affected by fermentation temperatures of 10 °C, 20 °C and 30 °C. Results demonstrated that, compared with 10 °C and 30 °C, 20 °C attenuated softening of Paocai by restraining microbial invasion and suppressing pectinolysis. Moreover, at 20 °C, a balanced molecular distribution and microbial community were achieved between vegetables and brine, thus accomplishing acid-production fermentation. By contrast, 10 °C and 30 °C promoted nonfermentative microbial genera, retarding fermentation. This study provided an understanding of the divergent influence of temperature on quality formation of fermented vegetables during fermentation.
Asunto(s)
Bacterias , Fermentación , Temperatura , Verduras , Bacterias/metabolismo , Bacterias/genética , Bacterias/clasificación , Bacterias/aislamiento & purificación , Verduras/microbiología , Verduras/metabolismo , Verduras/química , Microbiología de Alimentos , Microbiota , Alimentos Fermentados/microbiología , Alimentos Fermentados/análisis , Sales (Química)/química , Sales (Química)/metabolismoRESUMEN
In the context of global population growth expected in the future, enhancing the agri-food yield is crucial. Plant diseases significantly impact crop production and food security. Modern microfluidics offers a compact and convenient approach for detecting these defects. Although this field is still in its infancy and few comprehensive reviews have explored this topic, practical research has great potential. This paper reviews the principles, materials, and applications of microfluidic technology for detecting plant diseases caused by various pathogens. Its performance in realizing the separation, enrichment, and detection of different pathogens is discussed in depth to shed light on its prospects. With its versatile design, microfluidics has been developed for rapid, sensitive, and low-cost monitoring of plant diseases. Incorporating modules for separation, preconcentration, amplification, and detection enables the early detection of trace amounts of pathogens, enhancing crop security. Coupling with imaging systems, smart and digital devices are increasingly being reported as advanced solutions.