Foodborne diseases have always been a threat to human health. They are considered an emergent public health concern throughout the world. Many outbreaks have been found to be associated with biofilm. ...It is well documented that biofilm has become a problem in food industries as it renders its inhabitants resistant to antimicrobial agents and cleaning. In this review, biofilm formation in dairy, fish processing, poultry, meat, and Ready-To-Eat foods industries are discussed, as well as the biofilm forming abilities' of various microorganisms and the influence of food contact surface materials on biofilm formation. In addition, the conventional and emergent control strategies used to gain more proximity to efficiently maintain good hygiene throughout food industries is discussed.
Probiotics are live microorganisms that, when administered in adequate amounts, confer a health benefit on the host, are now accepted as suitable alternatives to antibiotics in the control of animal ...infections and improving animal production. Lactic acid bacteria (LAB) with remarkable functional properties have been evaluated in different studies as possible probiotic candidates. The purpose of this study was to isolate, characterize and assess the potentials of LAB from poultry gastrointestinal tract as potential poultry probiotics.
Potential LAB probiotics were isolated from broilers, characterized and evaluated for probiotic properties including antagonistic activity (against Escherichia coli, E. coli O157: H7, Enterococcus faecalis, Salmonella Typhimurium, S. Enteritidis and Listeria monocytogenes), survivability in simulated gastric juice, tolerance to phenol and bile salts, adhesion to ileum epithelial cells, auto and co-aggregation, hydrophobicity, α-glucosidase inhibitory activity, and antibiotic susceptibility tests. Most promising LAB strains with excellent probiotic potentials were identified by API 50 CHL and 16S rRNA sequencing as Lactobacillus reuteri I2, Pediococcus acidilactici I5, P. acidilactici I8, P. acidilactici c3, P. pentosaceus I13, and Enterococcus faecium c14. They inhibited all the pathogens tested with zones of inhibition ranging from 12.5 ± 0.71 to 20 ± 0 mm, and competitively excluded (P < 0.05) the pathogens examined while adhering to ileum epithelial cells with viable counts of 3.0 to 6.0 Log CFU/ml. The selected LAB strains also showed significant (P < 0.005) auto and co-aggregation abilities with α-glucosidase inhibitory activity ranging from 12.5 to 92.0%. The antibiotic susceptibility test showed 100.00% resistance of the LAB strains to oxacillin, with multiple antibiotic resistance indices above 0.5.
The selected LAB strains are ideal probiotic candidates which can be applied in the field for the improvement of poultry performance and control of pathogens in poultry, hence curtailing further transmission to humans.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The SARS‐CoV‐2 coronavirus is responsible for the current COVID‐19 pandemic, with an ongoing toll of over 5 million infections and 333 thousand deaths worldwide within the first 5 months. Insight ...into the phylodynamics and mutation variants of this virus is vital to understanding the nature of its spread in different climate conditions. The incidence rate of COVID‐19 is increasing at an alarming pace within subtropical South‐East Asian nations with high temperatures and humidity. To understand this spread, we analysed 444 genome sequences of SARS‐CoV‐2 available on the GISAID platform from six South‐East Asian countries. Multiple sequence alignments and maximum‐likelihood phylogenetic analyses were performed to analyse and characterize the non‐synonymous (NS) mutant variants circulating in this region. Global mutation distribution analysis showed that the majority of the mutations found in this region are also prevalent in Europe and North America, and the concurrent presence of these mutations at a high frequency in other countries indicates possible transmission routes. Unique spike protein and non‐structural protein mutations were observed circulating within confined area of a given country. We divided the circulating viral strains into four major groups and three subgroups on the basis of the most frequent NS mutations. Strains with a unique set of four co‐evolving mutations were found to be circulating at a high frequency within India, specifically. Group 2 strains characterized by two co‐evolving NS mutants which alter in RdRp (P323L) and spike (S) protein (D614G) were found to be common in Europe and North America. These European and North American variants have rapidly emerged as dominant strains within South‐East Asia, increasing from a 0% prevalence in January to an 81% by May 2020. These variants may have an evolutionary advantage over their ancestral types and could present a large threat to South‐East Asia for the coming winter.
Seafood forms a part of a healthy diet. However, seafood can be contaminated with foodborne pathogens, resulting in disease outbreaks. Because people consume large amounts of seafood, such disease ...outbreaks are increasing worldwide. Seafood contamination is largely due to the naturally occurring phenomenon of biofilm formation. The common seafood bacterial pathogens that form biofilms are Vibrio spp., Aeromonas hydrophila, Salmonella spp., and Listeria monocytogenes. As these organisms pose a global health threat, recent research has focused on elucidating methods to eliminate these biofilm-forming bacteria from seafood, thereby improving food hygiene. Therefore, we highlight recent advances in our understanding of the underlying molecular mechanisms of biofilm formation, the factors that regulate biofilm development and the role of quorum sensing and biofilm formation in the virulence of foodborne pathogens. Currently, several novel methods have been successfully developed for controlling biofilms present in seafood. In this review, we also discuss the epidemiology of seafood-related diseases and the novel methods that could be used for future control of biofilm formation in seafood.
•Bacterial biofilms contaminate seafood.•Most Vibrio spp. form biofilms on seafood.•Numerous factors affect biofilm formation on seafood.•Use of novel biofilm-reducing methods could minimize seafood-borne diseases.
Pasteurella multocida causes fowl cholera, a highly contagious poultry disease of global concern, causing significant ecological and economic challenges to the poultry industry each year. This study ...evaluated the effects of novel multi-strain probiotics consisting of Lactobacillus plantarum, L. fermentum, Pediococcus acidilactici, Enterococcus faecium and Saccharomyces cerevisiae on growth performance, intestinal microbiota, haemato-biochemical parameters and anti-inflammatory properties on broilers experimentally challenged with P. multocida. A total of 120 birds were fed with a basal diet supplemented with probiotics (10
CFU/kg) and then orally challenged with 10
CFU/mL of P. multocida. Probiotics supplementation significantly (P < 0.05) improved growth performance and feed efficiency as well as reducing (P < 0.05) the population of intestinal P. multocida, enterobacteria, and mortality. Haemato-biochemical parameters including total cholesterol, white blood cells (WBC), proteins, glucose, packed cell volume (PCV) and lymphocytes improved (P < 0.05) among probiotic fed birds when compared with the controls. Transcriptional profiles of anti-inflammatory genes including hypoxia inducible factor 1 alpha (HIF1A), tumor necrosis factor- (TNF) stimulated gene-6 (TSG-6) and prostaglandin E receptor 2 (PTGER2) in the intestinal mucosa were upregulated (P < 0.05) in probiotics fed birds. The dietary inclusion of the novel multi-strain probiotics improves growth performance, feed efficiency and intestinal health while attenuating inflammatory reaction, clinical signs and mortality associated with P. multocida infection in broilers.
Disease outbreaks from fresh produce have been increasing as a result of the increasing global consumption of produce. We evaluated the efficiency of cold oxygen plasma (COP), a new technology for ...the decontamination of fresh produce, in reducing biofilm of Aeromonas hydrophila, an emerging food-borne pathogen on lettuce. Lettuce leaves were inoculated with A. hydrophila at different temperatures to form biofilm and planktonic populations, and the inactivation kinetics of COP were determined using a modified Weibull model. To elucidate the antimicrobial mechanism of COP, we used field emission scanning electron microscopy (FESEM) and a quorum sensing (QS) assay. We found that 5min of treatment with COP significantly (p<0.05) reduced the biofilm populations of A. hydrophila on lettuce by 5.0-log incubation at lower than 15°C, whereas biofilm populations displayed enhanced resistance to COP treatment at higher temperatures (≥15°C). Planktonic populations also decreased by >5.0-log within 15s treatment of COP by incubating at any temperature. The mean Td-values for a 5-log reduction (analogous to the traditional D-value) ranged from 4.4–8.1s and 1.84–25.33min for the planktonic and biofilm populations, respectively. However, higher temperatures (≥15°C) resulted in a significantly higher QS (p<0.05) as well as biofilm formation and internalization in stomata, suggesting that higher biofilm formation and internalization might be the main factors mediating resistance to COP. In summary, this study highlights the impact of temperature on the modulation of QS, biofilm formation, internalization, and COP resistance in lettuce.
•Biofilms on lettuce are more resistant than planktonic cells to COP.•Temperature modulates QS and biofilm on lettuce surfaces and stomata.•Decontamination efficacy of COP on lettuce correlates with incubation temperature.•The Weibull model is a good fit for biofilms on lettuce treated by COP.•COP reduces food-borne pathogens on lettuce preserved at lower temperatures.
Aeromonas hydrophila recently has received increased attention because it is opportunistic and a primary human pathogen. A. hydrophila biofilm formation and its control are a major concern for food ...safety because biofilms are related to virulence. Therefore, we investigated biofilm formation, motility inhibition, quorum sensing, and exoprotease production of this opportunistic pathogen in response to various glucose concentrations from 0.05 to 2.5% (wt/vol). More than 0.05% glucose significantly impaired (P < 0.05) quorum sensing, biofilm formation, protease production, and swarming and swimming motility, whereas bacteria treated with 0.05% glucose had activity similar to that of the control (0% glucose). A stage shift biofilm assay revealed that the addition of glucose (2.5%) inhibited initial biofilm formation but not later stages. However, addition of quorum sensing molecules N-3-butanoyl-DL-homoserine lactone and N-3-hexanoyl homoserine lactone partially restored protease production, indicating that quorum sensing is controlled by glucose concentrations. Thus, glucose present in food or added as a preservative could regulate acyl-homoserine lactone quorum sensing molecules, which mediate biofilm formation and virulence in A. hydrophila.
Tracing the globally circulating severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) phylogenetic clades by high‐throughput sequencing is costly, time‐consuming, and labor‐intensive. We here ...propose a rapid, simple, and cost‐effective amplification refractory mutation system (ARMS)‐based multiplex reverse‐transcription polymerase chain reaction (PCR) assay to identify six distinct phylogenetic clades: S, L, V, G, GH, and GR. Our multiplex PCR is designed in a mutually exclusive way to identify V–S and G–GH–GR clade variants separately. The pentaplex assay included all five variants and the quadruplex comprised of the triplex variants alongside either V or S clade mutations that created two separate subsets. The procedure was optimized with 0.2–0.6 µM primer concentration, 56–60°C annealing temperature, and 3–5 ng/µl complementary DNA to validate on 24 COVID‐19‐positive samples. Targeted Sanger sequencing further confirmed the presence of the clade‐featured mutations with another set of primers. This multiplex ARMS‐PCR assay is a fast, low‐cost alternative and convenient to discriminate the circulating phylogenetic clades of SARS‐CoV‐2.
Highlights
Multiplex ARMS‐PCR (amplification refractory mutation system‐polymerase chain reaction) method for genotyping major severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2 clades).
Identify the mutated region of circulating phylogenetically SARS‐CoV‐2 clades.
PCR conditions were optimized and validated to identify V–S and G–GH–GR clade.
Salmonella Typhimurium (ST) is one of the leading causes of foodborne diseases in fresh produce, such as lettuce. Despite this, the role of the possible interactions between lettuce indigenous ...microorganisms and ST on their ability to form biofilm on lettuce and subsequently on the sensitivity of their sessile cells to ultraviolet C (UV-C) irradiation, remains relatively unexplored. Here, the interaction of a mixed-culture of ST and cultivable indigenous microorganisms (CIMs) was examined, as well as the efficacy of UV-C. Initially, the CIMs were isolated and cultured with ST at 15°C either planktonically or left to form biofilms on stainless steel (SS) and lettuce leaves. Microbial growth, biofilm formation, and survival following UV-C treatment were monitored using traditional plate count methods while biofilm formation, production of extracellular polymeric substance (EPS), and stomatal colonization were also observed by field emission scanning electron microscopy (FESEM). Internalization strength, color, and texture were analyzed by standard methods. Results revealed that the mixed-culture of ST and CIMs presented significantly (p<0.05) decreased biofilm formation on lettuce leaves compared to mono-cultures (i.e. ST or CIMs alone), which indicated competitive interaction between them, while no interactions were observed for biofilms on SS and for the planktonic cultures. It was also demonstrated that a mixed-culture biofilm on lettuce presented significantly higher resistance (p<0.05) to UV-C treatment compared to mono-culture biofilms, but such an effect was not observed for biofilms formed on SS and for the planktonic cultures. The Weibull model fitted well to microbial inactivation curves with R2 values that ranged from 0.90 to 0.97. Regarding the mixed-culture conditions, a UV-C fluency of 35mJ/cm2 was required to achieve a 5.0logCFU/mL or cm2 reduction in planktonic and biofilms on the SS for the mixed-culture, while 360mJ/cm2 was required to reduce biofilm cell number by approximately 2.0logCFU/cm2 on lettuce. Furthermore, FESEM analysis indicated higher EPS production, and greater stomatal colonization on lettuce mixed-cultures compared to mono-cultures. Finally, internalization strength was significantly higher (p<0.05) for the mixed-culture on lettuce, thus supporting the notion that internalization in lettuce is a factor that contributes to microbial UV-C resistance. The absence of adverse effects of UV-C on the color and texture of the lettuce suggests it as an alternative means of eliminating ST.
•Mixed-cultures of CIMs and ST show competitive interaction.•Weibull model fits well to UV-C efficacy on biofilms and planktonic populations.•Mixed-cultures biofilms on lettuce are more resistance to UV-C than mono-cultures.•Mixed-cultures of CIMs and ST enhance internalization on lettuce.•UV-C could be used to decontaminate lettuce without affecting lettuce quality.
TaqMan probe-based commercial real-time (RT) PCR kits are expensive but most frequently used in COVID-19 diagnosis. The unprecedented scale of SARS-CoV-2 infections needs to meet the challenge of ...testing more persons at a reasonable cost. This study developed a simple and cost-effective alternative diagnostic method based on melting curve analysis of SYBR green multiplex assay targeting two virus-specific genes along with a host-specific internal control. A total of 180 randomly selected samples portioning into two subsets based on crude and high-quality RNA extraction were used to compare this assay with a nationwide available commercial kit (Sansure Biotech Inc., (Hunan, China)), so that we could analyze the variation and validity of this in-house developed method. Our customized-designed primers can specifically detect the viral RNA likewise Sansure. We separately optimized SYBR Green RT-PCR reaction of N, E, S, and RdRp genes based on singleplex melting curve analysis at the initial stage. After several rounds of optimization on multiplex assays of different primer combinations, the optimized method finally targeted N and E genes of the SARS-CoV-2 virus, together with the β-actin gene of the host as an internal control. Comparing with the Sansure commercial kit, our proposed assay provided up to 97% specificity and 93% sensitivity. The cost of each sample processing ranged between ~2 and ~6 USD depending on the purification level of extracted RNA template. Overall, this one-step and one-tube method can revolutionize the COVID-19 diagnosis in low-income countries.
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