The present report is a review of uses of quaternary ammonium cations (QACs) as free monomers or immobilized in micelle-clay complexes in bacteria removal from water. The removal of bacteria from water by filtration through a bed of a granulated QAC-clay micelle was improved by minute concentrations of QAC that were released from the complex during filtration, which exerted biostatic or biocidal effects on the bacteria that emerged from the filter. The relationships between antibacterial activity (minimum inhibition concentration, MIC; minimum lethal concentration, MLC) and structural parameters of the QACs (head group size and alkyl chain length) are discussed. The antibacterial activity of QACs in aqueous phases is mainly due to the free monomeric species. Bacterial inactivation is enhanced by QACs with longer alkyl chains. In most recorded cases, however, minimum MIC and MLC values occurred at n = 14–16 and mostly at n = 16, where n is the number of C atoms in the alkyl chain. This outcome is explained by the combination of two antagonistic effects: (i) An increase in alkyl chain length (i.e., QAC hydrophobicity) enhances QAC binding, penetration, and destabilization of bacterial membranes; and (ii) an increase in alkyl chain length lowers the critical micelle concentration (CMC) of QACs and, thus, reduces QAC monomer concentrations, which more efficiently inactivate bacteria than the micelles. The octadecyltrimethylammonium (ODTMA, n = 18) MLC value (0.25 μm) for the cyanobacterium genus Aphanizomenon is significantly lower than the CMC (300 mm) value. Hence, a test to determine the minimum MLC value at n = 16 is of interest. Removal of bacteria from water by filtration is expected to be made more efficient by small increases in the ODTMA/clay ratio in the complex, which will act to increase the concentrations of ODTMA cations released during filtration.

A Canadian outbreak investigation was initiated in January 2022 after a cluster of cases of Shiga-toxin-producing Escherichia coli (STEC) O157 was identified through whole genome sequencing (WGS). Exposure information was collected through case interviews. Traceback investigations were conducted, and samples from case homes, retail, and the manufacturer were tested for STEC O157. Fourteen cases were identified in two provinces in Western Canada, with isolates related by 0–5 whole genome multi-locus sequence typing allele differences. Symptom onset dates ranged from 11 December 2021 to 7 January 2022. The median age of cases was 29.5 (range 0–61); 64% were female. No hospitalisations or deaths were reported. Of 11 cases with information available on fermented vegetable exposures, 91% (10/11) reported consuming Kimchi Brand A during their exposure period. The traceback investigation identified Manufacturer A in Western Canada as the producer. One open and one closed sample of Kimchi Brand A tested positive for STEC O157, with isolates considered genetically related by WGS to the outbreak strain. Napa cabbage within the kimchi product was hypothesised as the most likely source of contamination. This paper summarises the investigation into this STEC O157 outbreak associated with kimchi, the first reported outside of East Asia.

Dietary fiber (DF) is receiving increasing attention, and its importance in pig nutrition is now acknowledged. Although DF for pigs was frowned upon for a long time because of reductions in energy intake and digestibility of other nutrients, it has become clear that feeding DF to pigs can affect their well-being and health. This review aims to summarize the state of knowledge of studies on DF in pigs, with an emphasis on the underlying mode of action, by considering research using DF in sows as well as suckling and weaned piglets, and fattening pigs. These studies indicate that DF can benefit the digestive tracts and the health of pigs, if certain conditions or restrictions are considered, such as concentration in the feed and fermentability. Besides the chemical composition and the impact on energy and nutrient digestibility, it is also necessary to evaluate the possible physical and physiologic effects on intestinal function and intestinal microbiota, to better understand the relation of DF to animal health and welfare. Future research should be designed to provide a better mechanistic understanding of the physiologic effects of DF in pigs.

Resistance to carbapenems in human pathogens is a growing clinical and public health concern. The carbapenems are in an antimicrobial class considered last-resort, they are used to treat human infections caused by multidrug-resistant Enterobacterales, and they are classified by the World Health Organization as ‘High Priority Critically Important Antimicrobials’. The presence of carbapenem-resistant Enterobacterales (CREs) of animal-origin is of concern because targeted studies of Canadian retail seafood revealed the presence of carbapenem resistance in a small number of Enterobacterales isolates. To further investigate this issue, a risk profile was developed examining shrimp and salmon, the two most important seafood commodities consumed by Canadians and Escherichia coli, a member of the Enterobacterales order. Carbapenem-resistant E. coli (CREc) isolates have been identified in shrimp and other seafood products. Although carbapenem use in aquaculture has not been reported, several classes of antimicrobials are utilised globally and co-selection of antimicrobial-resistant microorganisms in an aquaculture setting is also of concern. CREs have been identified in retail seafood purchased in Canada and are currently thought to be uncommon. However, data concerning CRE or CREc occurrence and distribution in seafood are limited, and argue for implementation of ongoing or periodic surveillance.

This study aimed to determine the epidemiology and association of antimicrobial resistance (AMR) among Escherichia coli and Salmonella in Thailand. The E. coli (n = 1047) and Salmonella (n = 816) isolates from pigs, pork and humans were screened for 18 replicons including HI1, HI2, I1-γ, X, L/M, N, FIA, FIB, W, Y, P, FIC, A/C, T, FIIAs, F, K and B/O using polymerase chain reaction-based replicon typing. The E. coli (n = 26) and Salmonella (n = 3) isolates carrying IncF family replicons, ESBL and/or mcr genes were determined for FAB formula. IncF represented the major type of plasmids. Sixteen and eleven Inc groups were identified in E. coli (85.3%) and Salmonella (25.7%), respectively. The predominant replicon patterns between E. coli and Salmonella were IncK-F (23.7%) and IncF (46.2%). Significant correlations (P < 0.05) were observed between plasmid-replicon type and resistance phenotype. Plasmid replicon types were significantly different among sources of isolates and sampling periods. The most common FAB types between E. coli and Salmonella were F2:A-:B- (30.8%) and S1:A-:B- (66.7%), respectively. In conclusion, various plasmids present in E. coli and Salmonella. Responsible and prudent use of antimicrobials is suggested to reduce the selective pressures that favour the spread of AMR determinants. Further studies to understand the evolution of R plasmids and their contribution to the dissemination of AMR genes are warranted.

Shiga toxin-producing Escherichia coli (STEC) serogroup O157 is a zoonotic, foodborne gastrointestinal pathogen of major public health concern. We describe the epidemiology of STEC O157 infection in England by exploring the microbiological and clinical characteristics, the demographic and geographical distribution of cases, and examining changes in environmental exposures over 11 years of enhanced surveillance. Enhanced surveillance data including microbiological subtyping, clinical presentations and exposures were extracted for all cases resident in England with evidence of STEC O157 infection, either due to faecal culture or serology detection. Incidence rates were calculated based on mid-year population estimates from the Office of National Statistics (ONS). Demographics, geography, severity and environmental exposures were compared across the time periods 2009–2014 and 2015–2019. The number of cases reported to national surveillance decreased, with the mean cases per year dropping from 887 for the period 2009–2014 to 595 for the period 2015–2019. The decline in STEC O157 infections appears to be mirrored by the decrease in cases infected with phage type 21/28. Although the percentage of cases that developed HUS decreased, the percentage of cases reporting bloody diarrhoea and hospitalisation remained stable. The number of outbreaks declined over time, although more refined typing methods linked more cases to each outbreak. Integration of epidemiological data with microbiological typing data is essential to understanding the changes in the burden of STEC infection, assessment of the risks to public health, and the prediction and mitigation of emerging threats.

Our population-based study objectives were to describe characteristics and outcomes of Escherichia coli bloodstream infections (BSIs), and to evaluate factors associated with outcomes. We included incident E. coli BSIs from western interior residents (British Columbia, Canada; 04/2010–03/2020). We obtained data including patient demographics, location of onset, infection focus, Charlson comorbidity index (CCI), antimicrobial resistance, 30-day all-cause mortality and length of hospital stay (LOS). Using multivariable logistic regression models fitted with generalised estimating equations, we estimated factors associated with 30-day mortality and long post-infection LOS (>75th percentile). We identified 1080 incident E. coli BSIs in 1009 patients. The crude incidence and 30-day mortality rates were 59.1 BSIs and 6.8 deaths/100 000 person-years, respectively. The 30-day case fatality risk was 11.5%. Compared to community-acquired E. coli BSIs, either healthcare-associated or nosocomial cases had higher odds of 30-day mortality. Older cases, non-urogenital BSI foci and CCI ⩾ 3 had higher odds of 30-day mortality compared to younger cases, urogenital foci and CCI < 3. In patients that survived to discharge, those with extended-spectrum β-lactamase (ESBL)-producing E. coli BSIs, nosocomial BSIs, and CCI ⩾ 3 had higher odds of long post-infection LOS compared to those with non-ESBL-producing, community-acquired and healthcare-associated, and CCI < 3. There is a substantial disease burden from E. coli BSIs.

Brucellosis is one of the most serious and widespread zoonotic diseases, which seriously threatens human health and the national economy. This study was based on the T/B dominant epitopes of Brucella outer membrane protein 22 (Omp22), outer membrane protein 19 (Omp19) and outer membrane protein 28 (Omp28), with bioinformatics methods to design a safe and effective multi-epitope vaccine. The amino acid sequences of the proteins were found in the National Center for Biotechnology Information (NCBI) database, and the signal peptides were predicted by the SignaIP-5.0 server. The surface accessibility and hydrophilic regions of proteins were analysed with the ProtScale software and the tertiary structure model of the proteins predicted by I-TASSER software and labelled with the UCSF Chimera software. The software COBEpro, SVMTriP and BepiPred were used to predict B cell epitopes of the proteins. SYFPEITHI, RANKpep and IEDB were employed to predict T cell epitopes of the proteins. The T/B dominant epitopes of three proteins were combined with HEYGAALEREAG and GGGS linkers, and carriers sequences linked to the N- and C-terminus of the vaccine construct with the help of EAAAK linkers. Finally, the tertiary structure and physical and chemical properties of the multi-epitope vaccine construct were analysed. The allergenicity, antigenicity and solubility of the multi-epitope vaccine construct were 7.37–11.30, 0.788 and 0.866, respectively. The Ramachandran diagram of the mock vaccine construct showed 96.0% residues within the favoured and allowed range. Collectively, our results showed that this multi-epitope vaccine construct has a high-quality structure and suitable characteristics, which may provide a theoretical basis for future laboratory experiments.

Recent technological advances has led to the generation, storage, and sharing of colossal sets of information (‘big data’), and the expansion of ‘omics’ in science. To date, genomics/metagenomics, transcriptomics, proteomics, and metabolomics are arguably the most ground breaking approaches in food and public safety. Here we review some of the recent studies of foodborne pathogens (Campylobacter spp., Salmonella spp., and Escherichia coli) in poultry using big data. Genomic/metagenomic approaches have reveal the importance of the gut microbiota in health and disease. They have also been used to identify, monitor, and understand the epidemiology of antibiotic-resistance mechanisms and provide concrete evidence about the role of poultry in human infections. Transcriptomics studies have increased our understanding of the pathophysiology and immunopathology of foodborne pathogens in poultry and have led to the identification of host-resistance mechanisms. Proteomic/metabolomic approaches have aided in identifying biomarkers and the rapid detection of low levels of foodborne pathogens. Overall, ‘omics' approaches complement each other and may provide, at least in part, a solution to our current food-safety issues by facilitating the development of new rapid diagnostics, therapeutic drugs, and vaccines to control foodborne pathogens in poultry. However, at this time most ‘omics' approaches still remain underutilized due to their high cost and the high level of technical skills required.

In addition to a multifactorial etiology of nutritional, social and environmental stressors, post-weaning diarrhea (PWD) in pigs is often related to infection with specific pathogens such as enterotoxigenic Escherichia coli (ETEC). In swine farming operations, the incidence of PWD is a global concern and is associated with an unbalanced gut status, resulting in poor performance and high antimicrobial consumption via prophylaxis and metaphylaxis. Increases in antimicrobial resistance are reinforcing an already-urgent need for sustainable, alternative solutions for maintaining optimal gut health in livestock. Tannin-rich plants and extracts contain bioactive compounds that could be of great interest in this respect. This review describes how the use of tannins around weaning could be beneficial for pigs, with special emphasis on the reduction of ETEC-related PWD. An overview of the broad chemical diversity of tannins is presented together with their physicochemical and biological properties, as well as how they may be metabolized in the digestive tract. The pharmacological effects exerted by tannins are summarized; more precisely, the possible mechanisms by which tannins can disrupt the different steps of the pathogenesis of ETEC-related PWD are highlighted. The factors affecting the bioactivity of tannins are also discussed, shedding light on the importance of chemical structure among different tannins.

Among 469 US military veterans with an Escherichia coli clinical isolate (2012–2013), we explored healthcare and non-healthcare risk factors for having E. coli sequence type 131 and its H30 subclone (ST131-H30). Overall, 66 (14%) isolates were ST131; 51 (77%) of these were ST131-H30. After adjustment for healthcare-associated factors, ST131 remained positively associated with medical lines and nursing home residence. After adjustment for environmental factors, ST131 remained associated with wild animal contact (positive), meat consumption (negative) and pet cat exposure (negative). Thus, ST131 was associated predominantly with healthcare-associated exposures, while non-ST131 E. coli were associated with some environmental exposures.

Dientamoeba fragilis (D. fragilis) is an intestinal parasite frequently detected in humans with abdominal pain and diarrhoea, but it is also commonly found in asymptomatic subjects. Hence its clinical relevance is often disputed. The introduction of polymerase chain reaction (PCR) is a versatile and sensitive diagnostic technique for the detection of intestinal parasites, and in some Western world countries PCR has almost completely replaced microscopic diagnostics. PCR has however resulted in an increase in the number of D. fragilis-positive patients. The disputed pathogenic nature of this intestinal parasite and an apparent increase in the incidence of patients with positive PCR results have renewed the discussions between clinicians and microbiologists on how to deal with an infected patient. Moreover, treatment guidelines differ throughout the world which makes it difficult for clinicians to choose an optimal therapeutic regimen.

Thrombocytopenia is common in patients with invasive bacterial infections. Bacteria can activate platelets, but it is unclear if this affects platelet count. The aim of this study was to examine whether bacteraemia with Staphylococcus aureus, which readily activate human platelets, was more likely to be complicated by thrombocytopenia than bacteraemia with Escherichia coli or Streptococcus pneumoniae with different abilities to activate platelets.

We compared information from 600 adult patients with community-acquired bacteraemia with S. aureus (n = 140), E. coli (n = 420) and S. pneumoniae (n = 40) in Southern Sweden, 2012, linking information on positive blood cultures from microbiological databases and medical charts. The proportion of patients with thrombocytopenia (platelet count <150 × 109/ml) was calculated. Logistic regression was used to estimate the odds ratios (OR) for thrombocytopenia according to bacterial species adjusted for confounders.

The proportion of thrombocytopenia was 29% in S. aureus, 28% in E. coli and 20% in S. pneumonia bacteraemia (P = 0.50), corresponding to an OR of 1.2 (95% confidence interval 0.7–1.9) for thrombocytopenia for S. aureus as compared with E. coli or S. pneumoniae, adjusted for confounders.

This study indicates that platelet activation by bacteria is not a major causative mechanism in sepsis-associated thrombocytopenia.

Community-led total sanitation (CLTS) is an intervention that strives to end the practice of open defaecation. This study measured the effectiveness of CLTS in Nyando District by examining the association between community open defaecation-free (ODF) status and childhood diarrhoeal illness. A cross-sectional study design was used among households with children ⩽5 years old to ascertain information on acute diarrhoea in the past year (outcome), sanitation and health behaviours. Water testing was conducted to determine Escherichia coli and turbidity levels for 55 water sources. Data were obtained from 210 parents or caregivers from an ODF community and 216 parents or caregivers in a non-ODF community. The non-ODF participants reported a non-significant 16% increased risk of diarrhoea compared with the participants from the ODF community. Children's HIV positivity (adjusted prevalence ratio (aPR) = 2.29; 95% CI 2.07–2.53), unsafe child stool disposal (aPR = 1.92; 95% CI 1.74–2.12) and low household income (aPR = 1.93; 95% CI 1.46–2.56) were associated with diarrhoea, in the non-ODF community. The ODF location had a higher percentage of E. coli in the drinking water compared with the non-ODF location (76.7% vs. 60%). Diarrhoeal disease rates in children ⩽5 years old did not differ by whether a latrine intervention was implemented. Water sampling findings suggest water safety may have decreased the effectiveness of the CLTS’ improvement of childhood diarrhoea. Improved water treatment practices, safe stool disposal and education may improve the CLTS intervention in ODF communities and therefore reduced the risk of childhood diarrhoea.

We examined risk factors associated with the intestinal acquisition of antimicrobial-resistant extraintestinal pathogenic Escherichia coli (ExPEC) and development of community-acquired urinary tract infection (UTI) in a case-control study of young women across Canada. A total of 399 women were recruited; 164 women had a UTI caused by E. coli resistant to ⩾1 antimicrobial classes and 98 had a UTI caused by E. coli resistant to ⩾3 antimicrobial classes. After adjustment for age, student health service (region of Canada) and either prior antibiotic use or UTI history, consumption of processed or ground chicken, cooked or raw shellfish, street foods and any organic fruit; as well as, contact with chickens, dogs and pet treats; and travel to Asia, were associated with an increased risk of UTI caused by antimicrobial resistant E. coli. A decreased risk of antimicrobial resistant UTI was associated with consumption of apples, nectarines, peppers, fresh herbs, peanuts and cooked beef. Drug-resistant UTI linked to foodborne and environmental exposures may be a significant public health concern and understanding the risk factors for intestinal acquisition of existing or newly emerging lineages of drug-resistant ExPEC is important for epidemiology, antimicrobial stewardship and prevention efforts.

Shiga toxin-producing Escherichia coli (STEC) is a significant cause of gastrointestinal infection and the haemolytic-uremic syndrome (HUS). STEC outbreaks are commonly associated with food but animal contact is increasingly being implicated in its transmission. We report an outbreak of STEC affecting young infants at a nursery in a rural community (three HUS cases, one definite case, one probable case, three possible cases and five carriers, based on the combination of clinical, epidemiological and laboratory data) identified using culture-based and molecular techniques. The investigation identified repeated animal contact (animal farming and petting) as a likely source of STEC introduction followed by horizontal transmission. Whole genome sequencing (WGS) was used for real-time investigation of the incident and revealed a unique strain of STEC O26:H11 carrying stx2a and intimin. Following a public health intervention, no additional cases have occurred. This is the first STEC outbreak reported from Israel. WGS proved as a useful tool for rapid laboratory characterization and typing of the outbreak strain and informed the public health response at an early stage of this unusual outbreak.

Infectious diarrhoea is a worldwide problem in newborns. Optimal bacterial colonisation may enhance gut maturation and protect against pathogenic bacteria after birth. We hypothesised that lactic acid bacteria (LAB) administration prevents pathogen-induced diarrhoea in formula-fed newborns. Newborn caesarean-delivered, colostrum-deprived term piglets on parenteral nutrition for the first 15 h, were used as models for sensitive newborn infants. A commercially available probiotic strain, Lactobacillus paracasei F19 (LAP, 2·6×108 colony-forming units (CFU)/kg per d) and a novel LAB isolate, Pediococcus pentosaceus (PEP, 1·3×1010 CFU/kg per d), were administered for 5 d with or without inoculation of the porcine pathogen, Escherichia coli F18 (F18, 1010 CFU/d). This resulted in six treatment groups: Controls (n 9), LAP (n 10), PEP (n 10), F18 (n 10), F18–LAP (n 10) and F18–PEP (n 10). The pathogen challenge increased diarrhoea and density of F18 in the intestinal mucosa (P<0·05). LAB supplementation further increased the diarrhoea score, relative to F18 alone (P<0·01). Intestinal structure and permeability were similar among groups, whereas brush border enzymes were affected in variable intestinal regions with decreased activities in most cases after F18 and LAB inoculation. Bacterial density in colon mucosa increased after F18 inoculation (P<0·05) but was unaffected by LAB supplementation. In colon contents, acetic and butyric acids were increased by PEP (P<0·05). The LAB used in this study failed to reduce E. coli-induced diarrhoea in sensitive newborn pigs. In vulnerable newborns there may be a delicate balance among bacterial composition and load, diet and the host. Caution may be required when administering LAB to compromised newborns suffering from enteric infections.

Cytochrome P450s (CYPs or P450s) have been long recognized as very important enzymes in the metabolism of xenobiotic and endogenous compounds, but only a few CYPs have been functionally characterized in insects. The effort in functional characterization of insect P450s is heavily hindered by technical difficulties in preparing active, individual P450 enzymes directly from the target insect. In this paper, we describe the functional expression of two additional pyrethroid resistance-associated CYP9A genes (CYP9A12 and CYP9A17) from the polyphagous pest Helicoverpa armigera in the facile Escherichia coli. The functionality of E. coli produced CYP9A12, CYP9A14, and CYP9A17 was investigated and activities of these CYP9As were compared against three probe substrates after reconstitution with NADPH-dependent cytochrome P450 reductase. The results showed that active forms of CYP9A12 and CYP9A17 were expressed in E. coli with a content of about 1.0–1.5 nmol mg−1 protein in membrane preparations. In vitro assays showed that CYP9A14 was capable of catalyzing O-dealkylation of methoxyresorufin (MROD), ethoxyresorufin (EROD), and benzyloxyresorufin (BROD), while CYP9A12 and CYP9A17 exhibited only MROD and EROD activities. Kinetic studies demonstrated that CYP9A14 had the greatest kcat/Km value for MROD, and CYP9A17 for EROD, while the lowest kcat/Km values for both MROD and EROD were observed for CYP9A12. The distinct biochemical traits suggest that the three paralogous CYP9As may play different roles in xenobiotic metabolism in this important pest.

We studied the mammary immune response to different mammary pathogenic Escherichia coli (MPEC) strains in cows, hypothesising that the dynamics of response would differ. E. coli is a major aetiologic agent of acute clinical bovine mastitis of various degrees of severity with specific strains being associated with persistent infections. We compared challenge with three distinct pathogenic MPEC strains (VL2874, VL2732 and P4), isolated from different forms of mastitis (per-acute, persistent and acute, respectively). A secondary objective was to verify the lack of mammary pathogenicity of an environmental isolate (K71) that is used for comparison against MPEC in genomic and phenotypic studies. Twelve cows were challenged by intra-mammary infusion with one of the strains. Cellular and chemokine responses and bacterial culture follow-up were performed for 35 d. All cows challenged by any of the MPEC strains developed clinical mastitis. Differences were found in the intensity and duration of response, in somatic cell count, secreted cytokines (TNF-α, IL-6 and IL-17) and levels of milk leucocyte membrane Toll-like receptor 4 (TLR4). A sharp decrease of TLR4 on leucocytes was observed concomitantly to peak bacterial counts in milk. Intra-mammary infusion of strain K71 did not elicit inflammation and bacteria were not recovered from milk. Results suggest some differences in the mammary immune response to distinct MPEC strains that could be correlated to their previously observed pathogenic traits. This is also the first report of an E. coli strain that is non-pathogenic to the bovine mammary gland.