Enterobacteriaceae Bacteria Research Articles

Division of labor within psyllids: metagenomics reveals an ancient dual endosymbiosis with metabolic complementarity in the genus Cacopsylla.

Heritable beneficial bacterial endosymbionts have been crucial for the evolutionary success of numerous insects by enabling the exploitation of nutritionally limited food sources. Herein, we describe a previously unknown dual endosymbiosis in the psyllid genus Cacopsylla, consisting of the primary endosymbiont "Candidatus Carsonella ruddii" and a co-occurring Enterobacteriaceae bacterium for which we propose the name "Candidatus Psyllophila symbiotica." Its localization within the bacteriome and its small genome size confirm that Psyllophila is a co-primary endosymbiont widespread within the genus Cacopsylla. Despite its highly eroded genome, Psyllophila perfectly complements the tryptophan biosynthesis pathway that is incomplete in the co-occurring Carsonella. Moreover, the genome of Psyllophila is almost as small as Carsonella's, suggesting an ancient dual endosymbiosis that has now reached a precarious stage where any additional gene loss would make the system collapse. Hence, our results shed light on the dynamic interactions of psyllids and their endosymbionts over evolutionary time.

The effect of form and method of flavoring on microbiota of olive oil.

Flavoring olive oil is an increasing trend in olive oil processing. Growing consumer interest in flavored olive oils by natural material brings the need to evaluate the key limiting factors which is its microbiological stability. The present research compares the microbiological quality of olive oil flavored by 3 flavors (rosemary, garlic, and lemon), prepared by 3 methods to determine changes during storage. The comprehensive microbiological analyses (total number of microorganisms [TCM], anaerobic sporulates, yeasts, molds, bacteria of the family Enterobacteriaceae, bacteria of the genus Salmonella spp., Clostridium botulinum, and lactic acid bacteria) were conducted during 12 months of storage. The best results in TCM were observed in the oil flavored by fresh garlic (0.24 log CFU/mL). The highest counts of anaerobic sporulates were detected in the dried rosemary olive oil (1.10 log CFU/mL). The flavoring materials have significantly higher counts of microorganism than flavored oils (p < .05). The obtained results demonstrated that microorganisms are capable to survive in flavored olive oil and the method of flavoring can affect their growth in a selective way according to the chemical characteristics.

Broad-Host Dissemination of Plasmids Coharboring the fos Operon for Fructooligosaccharide Metabolism with Antibiotic Resistance Genes.

The fos operon encoding short-chain fructooligosaccharide (scFOS) utilization enables bacteria of the family Enterobacteriaceae to grow and be sustained in environments where they would struggle to survive. Despite several cases of the detection of the fos operon in isolates of avian and equine origins, its global distribution in bacterial genomes remains unknown. The presence of the plasmid-harbored fos operon among resistant bacteria may promote the spread of antibiotic resistance. A collection of 11,538 antimicrobial-resistant Enterobacteriaceae isolates from various sources was screened for the fosT gene encoding the scFOS transporter. Out of 307 fosT-positive isolates, 80% of them originated from sources not previously linked to fosT (humans, wastewater, and animals). The chromosomally harbored fos operon was detected in 163/237 isolates subjected to whole-genome sequencing. In the remaining 74 isolates, the operon was carried by plasmids. Further analyses focusing on the isolates with a plasmid-harbored fos operon showed that the operon was linked to various incompatibility (Inc) groups, including the IncHI1, IncF-type, IncK2, IncI1, and IncY families. Long-read sequencing of representative plasmids showed the colocalization of fos genes with antibiotic resistance genes (ARGs) in IncHI1 (containing a multidrug resistance region), IncK2 (blaTEM-1A), IncI1 [sul2 and tet(A)], and IncY [aadA5, dfrA17, sul2, and tet(A)] plasmids, while IncF-type plasmids had no ARGs but coharbored virulence-associated genes. Despite the differences in the locations and structures of the fos operons, all isolates except one were proven to utilize scFOSs. In this study, we show that the fos operon and its spread are not strictly bound to one group of plasmids, and therefore, it should not be overlooked. IMPORTANCE It was believed that members of the family Enterobacteriaceae are unable to grow under conditions with short-chain fructooligosaccharides as the only source of carbon. Nevertheless, the first Escherichia coli isolate from chicken intestine was able to utilize these sugars owing to the chromosomally harbored fos operon. Studies on E. coli isolates from horses discovered the horizontal transfer of the fos operon on IncHI1 plasmids along with genes for antibiotic resistance. The first plasmid detected was pEQ1, originating from the feces of a hospitalized horse in the Czech Republic. Follow-up studies also revealed the dissemination of the IncHI1 plasmid-harbored fos operon in the Netherlands, Germany, Denmark, and France among healthy horses. Despite several cases of detection of the fos operon, its global distribution in bacterial genomes remains unknown. The fos operon possibly plays a role in the adaptation of plasmids among resistant bacteria and therefore may promote the spread of antibiotic resistance.

Frequency and Distribution of Multidrug Resistance Enterobacteriaceae Isolated from Hospital and Community Acquired Urinary Tract Infection Patient Attended at a Tertiary Level Care Hospital in Dhaka City

Background: Urinary tract infection is caused by different bacteria of family enterobacteriaceae in the hospital and community acquired infection.&#x0D; Objective: The purpose of the present study was to find out the bacteria causing urinary tract infection, frequency as well as their antibiotic resistance pattern.&#x0D; Methodology: This cross-sectional study was conducted in the Department of Microbiology at National Institute of Neurosciences and Hospital, Dhaka, Bangladesh from June 2017 to November 2017 for a period of six months. Different urine samples of patient who were presented with infection in the urinary tract were included as study population. Using sterile container urine samples were taken from both IPD and OPD patients of National Institute of Neurosciences and Hospital, Dhaka, Bangladesh. The urine specimen was inoculated on blood and MacConkey agar plates and incubated at 37°C for 24 hours. Identification was based on standard microbiological methods The antibiogram testing was done by using modified Kirby-Bauer method. &#x0D; Results: A total of 200 urine samples were included for study of which 118(59%) cases showed positive and 82(41.0%) cases showed negative growth. Among 118 samples Escherichia coli were in 56(47.5%) isolates followed by Klebsiella pneumoniae were in 22(18.6%); Citrobacter freundii were in 20(16.9%); Pseudomonas species were 12(10.2%) and Proteus mirabilis were 8(6.8%). Escherichia coli was most predominant urinary tract infection causing species (47.5%) and found most resistant against cefixime (96.4%), azithromycin (92.9%), ciprofloxacin (71.4%); Klebsiella pneumonia was most resistant to amikacin, azithromycin (81.82%), ciprofloxacin, tazobactum/piperacillin (72.7%) cefixime, meropenem (63.7%). Citrobacter freundii was resistance to ciprofloxacin, cefixime (80.0%).&#x0D; Conclusion: Escherichia coli infections are more common in urinary tract infection patients and predominant resistant against cefixime followed by Klebsiella pneumonia.&#x0D; Bangladesh Journal of Infectious Diseases, December 2022;9(2):47-52

Effects of drying on the nutritional, sensory and microbiological quality of edible stinkbug (Encosternumdelgorguei)

Entomophagy has recently gained attention as a potential solution to the problems of food and nutritional security. One example is the consumption of edible stinkbug. Different drying techniques may affect the nutritional, microbiological and sensory properties of the edible stinkbugs. Thus, the study assessed the effects of toasting, microwave, oven and sun drying on the nutritional composition, microbiological quality and sensory attributes of processed edible stinkbugs. Drying significantly (p < 0.05) increased the crude protein and fat content of the edible stink bugs with the highest values being recorded for the toasted samples (66.65 & 37.17% respectively). Highest Ca, K, Zn, Mg, Fe and P values were recorded after microwave drying. Reduction of 2.94 and 2.99 log cycles of the total viable count (TVC) was observed in oven and microwave dried edible stinkbugs. Toasting and microwave drying eliminated the yeasts and moulds, Enterobacteriaceae and lactic acid bacteria (LAB) in edible stinkbugs. The appearance, aroma, taste, texture and overall acceptability scores were in the same order for toasted > oven dried > microwave dried > sun dried edible stinkbugs. Toasting, oven and microwave drying can be used for processing of edible stinkbugs.

Reduction of Microbial Contamination of Chechin nchabe (Cooked Fermented Cassava) Produced in Noun (West Cameroon) by a Second Fermentation

The Chechim nchabe is a traditional food widely consumed in Foumban, Foumbot, Koutaba, Massangam, Kouoptamo, Malentouen and Magba, 07 Departments of Noun (West region of Cameroon). It is obtained by fermenting cassava sticks cooked on the surface of river or spring water. Unfortunately, the bad hygienic quality of the environment during production promotes its contamination by pathogenic germs. The objective of this study is to carry out a second fermentation in order to reduce contamination of Chechim nchabe by pathogens germs during production. To achieve this objective, a survey on the socio-economic data, profile of the producers, production protocol and characteristics of product have been realized. After microbiological analysis of Chechim nchabe, a second fermentation was performed in the laboratory. From the results, it appears that all the producers are women, aged between 51 and 58 years and 87% of them not attending school. The water used for soaking the cassava revealed that 54% of women use river water and 46% spring water. The Chechim nchabe samples collected after traditional production in the 07 Departments of Noun, show average contamination of Enterobacteriaceae, moulds, staphylococci, Escherichia coli and lactic acid bacteria with respective concentrations of 4.7; 4.1; 4.4; 4.7 and 4.8 Log10ufc/mL. However, Chechim nchabe produced in urban areas such as Foumbot and Foumban recorded low contamination compared to that produced in rural areas like Massangam, which were heavily contaminated with Escherichia coli and Enterobacteriaceae. It was also noted that the Chechim nchabe produced in spring water is more contaminated than that produced in river water. The second fermentation for 10 hours of Chechim nchabe in a basin, after 12 hours of traditional fermentation, eliminated all of pathogenic germs from Chechim nchabe. This second fermentation of 10 hours could be a solution to guarantee the sanitary quality of Chechim nchabe before its consumption.

Glabridin inhibited the spread of polymyxin-resistant Enterobacterium carrying ICEMmoMP63.

The role of integrative and conjugative elements (ICEs) in antibiotic resistance in Morganella morganii is unknown. This study aimed to determine whether an ICE identified in the M. morganii genome contributed to the polymyxin resistance. Whole-genome sequencing was performed followed by bioinformatics analyses to identify ICEs and antibiotic resistance genes. Conjugation assays were performed to analyze the transferability of a discovered ICE. A drug transporter encoded on the ICE was heterogeneously expressed in Escherichia coli, minimum inhibitory concentrations of antibiotics were determined, and a traditional Chinese medicine library was screened for potential efflux pump inhibitors. An antibiotic resistance-conferring ICE, named ICEMmoMP63, was identified. ICEMmoMP63 was verified to be horizontally transferred among Enterobacteriaceae bacteria. G3577_03020 in ICEMmoMP63 was found to mediate multiple antibiotic resistances, especially polymyxin resistance. However, natural compound glabridin was demonstrated to inhibit polymyxin resistance. Our findings support the need for monitoring dissemination of ICEMmoMP63 in Enterobacteriaceae bacteria. Combined glabridin and polymyxin may have therapeutic potential for treating infections from multi-drug resistant bacteria carrying ICEMmoMP63.

Fecal carriage and molecular epidemiology of mcr-1-harboring Escherichia coli from children in southern China

BackgroundThe increase of multidrug-resistant Enterobacteriaceae bacteria has led to the reintroduction of colistin for clinical treatments, and colistin has become a last resort for infections caused by multidrug-resistant bacteria. Enterobacteriaceae bacteria carrying the mcr-1 gene are majorly related to colistin resistance, which may be the main reason for the continued increase in the colistin resistance rate of Enterobacteriaceae. The study aimed to investigate the sequence type and prevalence of Escherichia coli (E. coli) harboring the mcr-1 gene in the gut flora of children in southern China. MethodsFecal samples (n = 2632) of children from three medical centers in Guangzhou were cultured for E. coli. The mcr-1-harboring isolates were screened via polymerase chain reaction (PCR). The colistin resistance transfer frequency was studied by conjugation experiments. DNA sequencing data of seven housekeeping genes were used for multi-locus sequence typing analysis (MLST). ResultsPCR indicated that 21 of the 2632 E. coli (0.80%) isolates were positive for mcr-1; these strains were resistant to colistin. Conjugation experiments indicated that 18 mcr-1-harboring isolates could transfer colistin resistance phenotypes to E. coli J53. MLST analysis revealed that the 21 isolates were divided into 18 sequence types (STs); E. coli ST69 was the most common (14.3%), followed by E. coli ST58 (9.5%). ConclusionThese results demonstrate the colonization dynamics and molecular epidemiology of E. coli harboring mcr-1 in the gut flora of children in southern China. The mcr-1 gene can be horizontally transmitted within species; hence, it is necessary to monitor bacteria that harbor mcr-1 in children.

Real-Time PCR based Rapid and Culture-Independent Detection of Citrobacter: ‘An Alarming State for Environment and Human Health’

The changing global scenario of environmental conditions and altered microbial community has severely deteriorated the quality of water which enforced an elevated health risks on human beings due to unavailability of safe and pristine water. Citrobacter is one of the fecal coliform bacteria of family Enterobacteriaceae. It is an opportunistic pathogen formerly used as an indicator bacterium along with other fecal coliforms namely Escherichia coli, Klebsiella and Enterobacter, but is now known to cause several diseases in human beings. In present study we collected 135 samples from potable water and riverine-systems and confirmed the existence of Citrobacter using the conserved sequence of gnd (6-phosphogluconate dehydrogenate) gene with the application of SYBR green real-time PCR, which demonstrated extremely high specificity, fidelity and stringency in detection strategy. The Citrobacter counts in potable water were in the range of zero to 1.54 x104 ± 572.88 cfu/100ml. The Citrobacter levels in surface water were 2.18 x104 ±848, 1.54 x104 ±462, 3.53 x104 ±1299, 2.57 x104 ±912, 8.78 x103 ±201, 1.28 x104 ±370, CFU/100ml; associated with hydrophytes were 6.24 x104 ±1535, 8.42 x104 ±2711, 1.19 x105 ±4792, 1.12 x105 ±4177, 8.32 x104 ±2329, 8.08 x104 ±2149 CFU/10g and in the sediments the counts were 2.50 x104 ±647, 5.02 x104 ±1852, 3.26 x104 ±1186, 7.65 x104 ±2884, 1.50 x104 ±355, and 2.56 x104 ±737 CFU/10g at sampling site # 1, site # 2, site # 3, site # 4, site # 5 and site # 6, respectively. The present assay could be applied in the detection and regular monitoring of potable water and other environmental samples to check waterborne diseases and outbreaks caused by Citrobacter.

Monitoring and traceability of spoilage bacteria from three representative braised chickens based on culture-dependent and high-throughput sequencing

Culture-dependent methods and high-throughput sequencing technology were used to monitor the spoilage bacteria of braised chickens from three regions. The microorganisms in the braised chickens, which were vacuum-packed and stored at 4 °C, were isolated, identified, and traced, and the changes in meat quality were also measured. The high-throughput sequencing of braised chickens from different regions showed that the bacterial diversity decreased and the relative abundance increased during storage. At the end of storage, Lactobacillus, Brochothrix, Leuconostoc, Carnobacterium, and Enterobacteriaceae; Lactobacillus, Weissella, Aerococcus, Enterobacter, and Lactococcus; Enterobacteriaceae, Enterococcus, Serratia, Vagococcus, Lactobacillus, and Hafnia-obesumbacterium were the dominant microorganisms of braised chickens from the three regions. Twelve strains, namely Lactobacillus curvatus, Weissella viridescens, Leuconostoc citreum, Lactobacillus sakei, Brochothrix thermophacta, Serratia liquefaciens, Weissella hellenica, Lelliottia amnigena, Pantoea agglomerans, Rahnella sp., Enterococcus devriesei, and Enterobacteriaceae bacterium, were isolated and identified. The random forest method was used to predict the source of the samples according to the species of bacteria, and prediction accuracies of 91.7%, 83.3%, and 75% at the order, family, and genus levels, respectively, were achieved. The source of food spoilage bacteria could be traced with high accuracy through the sample microorganism, which provides a new direction for the study of food spoilage bacteria.

Quarantine and Antibiotic Susceptibility of Enterobacteriaceae Strains and other Gram-Negative Bacteria in Dairy Sweetmeat Milk (Doodh) Peda

The present study aimed to assess the prevalence and isolation of Enterobacteriaceae strains and other gram-negative bacteria of milk (doodh) peda-a traditional milk product of India. Bacteria of the family Enterobacteriaceae are the indicator organisms that provide evidence of poor hygiene, inadequate processing or post-process contamination of foods. A total of 25 peda samples were collected from different places in the Mysuru district to evaluate the prevalence of Enterobacteriaceae. Seventeen gram-negative fermentative bacteria of clinical significance were detected and isolated. API 20E biochemical identification syatem and other associated biochemical tests are used as a supportive tool to identify gram-positive and gram-negative bacteria. Our outcomes indicate that milk peda contaminated with the Enterobacteriaceae like Enterobacter cloacae, Yersinia bercovieri, Yersinia rohdei, Raoutlella terigena, Acinetobacter lwoffii, Pantoea agglomerans PA2, Klebsiella pneumoniae subsp pneumoniae, Leclericia adecarboxylata, Photorhabdus nematophilus, Enterobacter gergoviae, Acinetobacter baumannii/calcoacetius, Cronobacter sakazaki (Enterobacter sakazaki). Further, the antimicrobial resistance of these Enterobacteriaceae groups was also investigated against 20 antibiotics by the disc diffusion assay method. All isolates revealed susceptibility to the fluoroquinolones and aminoglycosides. But resistance to the nitrofurantoin (70.59 %), augmentin (52.94%), and cefpodoxime (47.06%) antibiotics. Our finding was the first report of the prevalence and detection of E. gergoviae in a food sample (milk peda) and examined for antibiotic resistance.

Edible film based on corn zein containing dill extract and essential oil/β-cyclodextrin inclusion complex: Shelf life enhancement of common carp fillet.

The aim of this study was to examine the impacts of corn zein edible film (Z) fortified with dill leaves extract (DE) and encapsulated dill essential oil with β-cyclodextrin (nDEO) on the quality of refrigerated common carp fillet. Gas chromatography/mass spectrometry (GC/MS) analysis showed that the most frequent substances of DEO were apiol (35.1%) and carvone (31.4%), respectively. Designated treatments were as follows: (1) Control (C), (2) Z, (3) Z-DE, (4) Z-DEO, (5) Z-nDEO, (6) Z-DE-DEO, and (7) Z-DE-nDEO. The physicochemical properties (thickness, moisture percent, tensile strength, elongation at break, Young's modulus, color, morphology, functional groups, and thermal resistance) of the activated films significantly improved (p ≤ .05). The total viable counts, lactic acid bacteria, Enterobacteriaceae, and psychrotrophic bacteria significantly decreased in all wrapped fillets compared to the unwrapped ones (p ≤ .05). Throughout storage period, the wrapped fillets exhibited lower changes in pH, thiobarbituric acid reactive substances, and total volatile-based nitrogen values than the unwrapped fillets. According to the sensory findings, incorporating DE and nDEO in the zein films created significantly desirable aroma and flavor in the wrapped samples during storage time (p ≤ .05). Encapsulation of DEO with β-cyclodextrin significantly fortified preservative effects of the films in fish fillets during storage period (p ≤ .05). In conclusion, the designated composite zein edible film containing DE and nDEO can be introduced as an active edible packaging in the shelf life improvement of common carp fillets during cold storage.

Fate of Shiga Toxin-Producing Escherichia coli (STEC) and Salmonella during Kosher Processing of Fresh Beef

Traditional kosher meat processing involves the following steps after slaughtering: soaking with water to remove blood, salting to help draw out more blood, and rinsing to remove salt. However, the impact of the salt used on foodborne pathogens and beef quality is not well understood. The objectives of the current study were to determine the effectiveness of salt in reducing pathogens in a pure culture model, on surfaces of inoculated fresh beef during kosher processing, and the effect of salt on beef quality. The pure culture studies indicated that the reduction of E. coli O157:H7, non-O157 STEC, and Salmonella increased with increasing salt concentrations. With salt concentrations from 3 to 13%, salt reduced E. coli O157:H7, non-O157 STEC, and Salmonella ranging from 0.49 to 1.61 log CFU/mL. For kosher processing, the water-soaking step did not reduce pathogenic and other bacteria on the surface of fresh beef. Salting and rinsing steps reduced non-O157 STEC, E. coli O157:H7, and Salmonella ranging from 0.83 to 1.42 log CFU/cm2, and reduced Enterobacteriaceae, coliforms, and aerobic bacteria by 1.04, 0.95, and 0.70 log CFU/cm2, respectively. The salting process for kosher beef resulted in reducing pathogens on the surface of fresh beef, color changes, increased salt residues, and increased lipid oxidation on the final products.

Spontaneous bacterial peritonitis by Listeria monocytogenes. A rare case and literature review

Spontaneous bacterial peritonitis (SBP) is a bacterial infection of ascites and a common complication in patients with cirrhosis, associated with a high morbidity and mortality rate. Gram-negative Enterobacteriaceae bacteria are usually the major pathogens involved in SBP, with Klebsiella pneumoniae accounting for 50% of these. Individuals with chronic liver and /or kidney disease associated with long-standing ascites are predisposed to SBP. Nosocomial SBP presents most commonly a poorer outcome. Although Listeria monocytogenes peritonitis is a relatively rare focal manifestation of Listeria infection, its incidence is increasing. It is associated with a mortality rate approaching 30% in cases of systemic involvement, despite first-line therapy. To our knowledge, this is the first case of L.monocytogenes-associated SBP described in Italy. Clinicians should be aware of the uncommon agents of SBP, such as Listeria, because, if diagnosed early, early antibiotic administration is crucial in minimizing adverse outcomes.

Effect of coating with chitosan enriched with different borates on the shelf life of fish fillet.

In this study, the effects of biofilm coatings obtained by immobilization of different borates - namely borax (BX), colemanite (COL), and ulexite (UX) - with chitosan (Ch) on the shelf life of rainbow trout fillets were investigated. The immobilization and characterization of borates in Ch were confirmed by scanning electron microscopy, Fourier transform infrared spectroscopy, and zeta potential analysis. In determining the shelf life of fillets that were covered by immersion and stored for 15 days, microbiological (total aerobic mesophilic, psychrotrophic, lactic acid, Pseudomonas, and Enterobacteriaceae bacteria counts) and chemical analyses (total volatile basic nitrogen, thiobarbituric acid reactive substance, and pH levels) were performed at 3day periodic intervals. In addition, the biodegradation of borates was determined using inductively coupled plasma mass spectrometry in biofilm-coated fillets on the 1st, 8th, and 15th storage days. The microbial results of the coatings enriched with borates (BX, COL, and UX) at different levels (0, 0.03, and 0.06 mg L-1 ) (due to the immobilization with Ch) show the shelf life was extended by 3-6 days in all of the treatment groups compared with the control. It was concluded that BX, COL, and UX coatings enriched by immobilization with Ch increase shelf life and improve fillet quality. In addition, the enrichment of BX, COL, and UX with Ch showed explicit natural protective effects. This study demonstrates that Ch-enriched coatings of BX, COL, and UX can be used as natural bioactive nanocarriers to provide bioactive food ingredients in the seafood processing industry. © 2023 Society of Chemical Industry.

Aprosamine Derivatives Active against Multidrug-Resistant Gram-Negative Bacteria

Novel aprosamine derivatives were synthesized for the development of aminoglycoside antibiotics active against multidrug-resistant Gram-negative bacteria. The synthesis of aprosamine derivatives involved glycosylation at the C-8' position and subsequent modification (epimerization and deoxygenation at the C-5 position and 1-N-acylation) of the 2-deoxystreptamine moiety. All 8'-β-glycosylated aprosamine derivatives (3a-h) showed excellent antibacterial activity against carbapenem-resistant Enterobacteriaceae and 16S ribosomal RNA methyltransferase-producing multidrug-resistant Gram-negative bacteria compared to the clinical drug, arbekacin. The antibacterial activity of 5-epi (6a-d) and 5-deoxy derivatives (8a,b and 8h) of β-glycosylated aprosamine was further enhanced. On the other hand, the derivatives (10a,b and 10h) in which the amino group at the C-1 position was acylated with (S)-4-amino-2-hydroxybutyric acid showed excellent activity (MICs 0.25-0.5 μg/mL) against resistant bacteria that produce the aminoglycoside-modifying enzyme, aminoglycoside 3-N-acetyltransferase IV, which induces high resistance against parent apramycin (MIC > 64 μg/mL). In particular, 8b and 8h showed approximately 2- to 8-fold antibacterial activity against carbapenem-resistant Enterobacteriaceae and 8- to 16-fold antibacterial activity against resistant Gram-positive bacteria, such as methicillin-resistant Staphylococcus aureus and vancomycin-resistant enterococci, compared to apramycin. Our results showed that aprosamine derivatives have immense potential in the development of therapeutic agents for multidrug-resistant bacteria.

A267 IDENTIFYING ENTEROBACTERIACEAE VIRULENCE GENES ASSOCIATED WITH ACTIVE DISEASE IN ULCERATIVE COLITIS PATIENTS USING CULTURE-DEPENDENT AND -INDEPENDENT APPROACHES

Abstract Background The prevalence of inflammatory bowel disease (IBD) in Canada is among the highest in the world and is estimated to affect 1 in 100 Canadians by 2030. Ulcerative colitis (UC) is a type of IBD characterized by mucosal inflammation of the large intestine. UC is believed to arise through a complex interplay of the host immune responses and changes in the gut microbiota in a genetically susceptible individual. Therapies targeting the gut microbiota, such as antibiotics and fecal microbiota transplantation (FMT), have been effective in treating UC, suggesting infectious triggers should be explored. Purpose Some data suggests the development of UC can be driven by pathogenic bacteria of the family Enterobacteriaceae, which can carry virulence genes important for colonizing the gut (e.g. fimH) and disrupting the intestinal epithelium (e.g. hylA). However, many studies have focused on a single species (e.g. Escherichia coli) and thereby underestimate the importance of these virulence genes that are shared across the Enterobacteriaceae family. I aim to investigate whether specific virulence genes contribute to disease activity in some patients with UC and to show that these virulence genes are carried by strains of many Enterobacteriaceae species. Method UC patient stool samples were collected throughout enrolment in randomized control trials of FMT for adult UC and microbiome studies in early-onset pediatric UC. The stool samples were cultured on MacConkey agar to enrich for Enterobacteriaceae. Samples from before and after treatment were sent for targetted cultured-enriched metagenomic sequencing and strains were isolated from baseline samples only for whole genome sequencing. The taxonomy of each genome and taxonomic composition of each metagenome were annotated along with virulence genes and antimicrobial resistance genes. Phenotypic assays of cultured isolates were used to capture diversity and virulence activity. Result(s) Approximately 7500 colonies from UC patient stool samples were isolated and phenotyped. Based on the initial screens, 130 isolates were selected to comprise our Enterobacteriaceae strain collection. Across all patient samples, we detected 19 different species of the Enterobacteriaceae family across six genera from the genomic and metagenomic data. We identified virulence genes found across multiple species from the Enterobacteriaceae family within genomes and metagenomes, and by performing phenotypic assays of the cultured isolates. Conclusion(s) Further exploration of the distribution of these virulence genes in UC patients during active disease or remission and healthy controls can provide insight into the pathogenesis of UC. Identifying infectious agents in even a subset of UC patients will allow for more targeted diagnosis and treatment approaches. Disclosure of Interest None Declared

Impact of Longkong Pericarp Extract on the Physicochemical Properties of Alginate-Based Edible Nanoparticle Coatings and Quality Maintenance of Shrimp (Penaeus monodon) during Refrigerated Storage.

The objective of this study was to evaluate the impact of varying concentrations of longkong pericarp extract (LPE) on the physicochemical properties of alginate-based edible nanoparticle coatings (NP-ALG) on shrimp. For developing the nanoparticles, the alginate coating emulsion with different LPE concentrations (0.5, 1.0, and 1.5%) was ultrasonicated at 210 W with a frequency of 20 kHz for 10 min and a pulse duration of 1s on and 4 off. After that, the coating emulsion was separated into four treatments (T): T1: Coating solution containing basic ALG composition and without the addition of LPE or ultrasonication treatment; T2: ALG coating solution converted into nano-sized particles with ultrasonication and containing 0.5% LPE; T3: ALG coating solution converted into nano-sized particles with ultrasonication and containing 1.0% LPE; T4: ALG coating solution converted into nano-sized particles with ultrasonication and containing 1.5% LPE. A control (C) was also used, where distilled water was used instead of ALG coating. Before coating the shrimp, all the coating materials were tested for pH, viscosity, turbidity, whiteness index, particle size, and polydispersity index. The control samples had the highest pH and whiteness index and was followed by the lowest viscosity and turbidity (p < 0.05). Among the T1-T4 coating materials, T4 coating had higher turbidity, particle size, polydispersity index, but lower pH, viscosity, and whiteness index (p < 0.05). To study the quality and shelf-life of the shrimp, all coated shrimp samples were refrigerated at 4 °C for a period of 14 days. At 2-day intervals, physiochemical and microbial analyses were performed. The coated shrimp also had a lower increase in pH and weight loss over the storage period (p < 0.05). Coatings containing 1.5% LPE significantly reduced the polyphenol oxidase activity in the shrimp (p > 0.05). The addition of LPE to NP-ALG coatings demonstrated dose-dependent antioxidant activity against protein and lipid oxidation. The highest LPE concentration (1.5%) led to increased total and reactive sulfhydryl content, along with a significant decrease in carbonyl content, peroxide value, thiobarbituric acid reactive substances, p-anisidine, and totox values at the end of the storage period (p < 0.05). Additionally, NP-ALG-LPE coated shrimp samples exhibited an excellent antimicrobial property and significantly inhibited the growth of total viable count, lactic acid bacteria, Enterobacteriaceae, and psychotropic bacteria during storage. These results suggested that NP-ALG-LPE 1.5% coatings effectively maintained the quality as well as extended the shelf-life of shrimp during 14 days of refrigerated storage. Therefore, the use of nanoparticle-based LPE edible coating could be a new and effective way to maintain the quality of shrimp during prolonged storage.

Influences of growth stage and ensiling time on fermentation profile, bacterial community compositions and their predicted functionality during ensiling of Italian ryegrass

The study evaluated the effects of growth stage and ensiling time on silage fermentation characteristics, bacterial communities and their predicted functional potential in Italian ryegrass (Lolium multiflorum Lam.) silage. Italian ryegrass (IR) was harvested at heading (Earing rate >50 %, IR1) and blooming stages (>50% bloom, IR2), respectively. The harvested IR was ensiled in 15-L plastic silos. The experiment had a completely randomized design. Triplicate silos were sampled after 1, 3, 7, 15, 30 and 60 days of fermentation, respectively. The fermentation products were analyzed on each sampling day. The bacterial communities and their functional potential and phenotype on day 3 and 60 were analyzed by high-throughput sequencing technique and PICRUSt2 (Phylogenetic Investigation of Communities by Reconstruction of Unobserved States) method. With the advancing maturity of IR, the neutral detergent fiber and dry matter (DM) contents, lactic acid bacteria, yeast, Enterobacteriaceae and aerobic bacteria populations increased, while water soluble carbohydrate contents and buffering capacity decreased. Larger lactic acid contents were accumulated in IR1 than IR2 at the early stage of fermentation. Higher contents of ethanol and ammonia nitrogen (NH3-N) were found in IR1 compared to IR2 at the late stage of ensiling. After 60 days, IR1 and IR2 both had good fermentation quality with low pH values (∼4.08), and acceptable levels of NH3-N (∼67.6 g/kg total nitrogen) and butyric acid (∼1.08 g/kg DM). The IR2 had lower abundance of Lactobacillus on day 3, and higher abundances of Kosakonia and Pantoea on day 60 compared to IR1. The bacterial community in IR2 had higher activity in metabolic pathway. Overall, high throughput sequencing technique combined with PICRUSt2 method can improve our understanding of the silage microbiology to further regulate the fermentation products.

Assessment of Starters of Lactic Acid Bacteria and Killer Yeasts: Selected Strains in Lab-Scale Fermentations of Table Olives (Olea europaea L.) cv. Leccino

Olives debittering, organoleptic quality and safety can be improved with yeasts and lactic acid bacteria (LABs) selected strain starters, that allow for better fermentation control with respect to natural fermentation. Two selected killer yeasts (Wickerhamomyces anomalus and Saccharomyces cerevisiae) and Lactobacillus plantarum strains were tested for olive (cv. Leccino) fermentation to compare different starter combinations and strategies; the aim was to assess their potential in avoiding pretreatments and the use of excessive salt in the brines and preservatives. Lactobacilli, yeasts, molds, Enterobacteriaceae and total aerobic bacteria were detected, as well as pH, soluble sugars, alcohols, organic acids, phenolic compounds, and rheological properties of olives. Sugars were rapidly consumed in the brines and olives; the pH dropped quickly, then rose until neutrality after six months. The oleuropein final levels in olives were unaffected by the treatments. The use of starters did not improve the LABs’ growth nor prevent the growth of Enterobacteriaceae and molds. The growth of undesirable microorganisms could have been induced by the availability of selective carbon source such as mannitol, whose concentration in olive trees rise under drought stress. The possible role of climate change on the quality and safety of fermented foods should be furtherly investigated. The improvement of olives’ nutraceutical value can be induced by yeasts and LABs starters due to the higher production of hydroxytyrosol.