Biofilm-forming capacity of Escherichia coli isolated from cattle and beef packing plants: relation to virulence attributes, stage of processing, antimicrobial interventions, and heat tolerance.

Despite the importance of biofilm formation in contamination of meat by pathogenic Escherichia coli at slaughter plants, drivers for biofilm remain unclear. To identify selection pressures for biofilm, we evaluated 745 isolates from cattle and 700 generic E. coli from two beef slaughter plants for motility, expression of curli and cellulose, and biofilm-forming potential. Cattle isolates were also screened for serogroup, stx1 , stx2 , eae and rpoS. Generic E. coli were compared by source (hide of carcass, hide-off carcass, processing equipment) before and after implementation of antimicrobial hurdles. The proportion of E. coli capable of forming biofilms was lowest (7.1%; P < 0.05) for cattle isolates and highest (87.3%; P < 0.05) from equipment. Only one enterohemorrhagic E. coli (EHEC) was an extremely-strong biofilm-former, in contrast to 73.4% of E. coli from equipment. Isolates from equipment after sanitation had a greater biofilm-forming capacity ( P < 0.001) than those before sanitation. Most cattle isolates were motile and expressed curli, although these traits along with expression of cellulose and detection of rpoS were not necessary for biofilm formation. In contrast, isolates capable of forming biofilms on equipment were almost exclusively motile and able to express curli. Results of the present study indicate that cattle would rarely carry EHEC capable of making strong biofilms to slaughter plants. However, if biofilm-forming EHEC contaminated equipment, current sanitation procedures may not eliminate the most robust biofilm-forming strains. Accordingly, new and effective anti-biofilm hurdles are required for meat-processing equipment to reduce future instances of food-borne disease. Importance As the majority of enterohemorrhagic E. coli (EHEC) are not capable of forming biofilms, sources were undetermined of the biofilm-forming EHEC isolated from ‘high-event periods’ in beef slaughter plants. This study demonstrated that sanitation procedures used on beef-processing equipment may inadvertently lead to survival of robust biofilm-forming strains of E. coli . Cattle only rarely carry EHEC capable of forming strong biofilms (1/745 isolates evaluated), but isolates with greater biofilm-forming capacity were more likely ( P < 0.001) to survive equipment sanitation. In contrast, chilling carcasses for 3 days at 0°C reduced ( P < 0.05) the proportion of biofilm-forming E. coli . Consequently, an additional anti-biofilm hurdle for meat-processing equipment, perhaps involving cold exposure, is necessary to further reduce the risk of food-borne disease.

1324Clinical Registry for Acute Respiratory Infections in Children in Western Australia

Background Acute respiratory infections (ARIs) are the leading cause for emergency presentation and a major driver for antibiotic use in children. In 2020, we established an ARI clinical registry to: evaluate clinical care for ARI to inform clinical guidelines; and as a platform for clinical trials assessing antimicrobial interventions. Methods Any child &lt;16 years presenting to Perth Children’s Hospital Emergency Department (ED) with cough, fever, sore throat and/or difficulty breathing was eligible for enrolment. Using an automated survey sent to parents’ mobile phones, each enrolled child was followed weekly until 28 days or disease recovery (whichever occurred first). Data collected included clinical symptoms, antibiotic prescription, adherence, and duration to return to regular activity (recovery). Results From Feb 2020-April 2021, 448 participants were enrolled (84% &lt;5 years). Fever and cough were the most frequently reported symptoms. Of 448, 274 (61%) ARI cases completed all surveys until recovered. The median recovery length was 9 days (IQR:6-12). The recovery days were longer, although not statistically significant (p &gt; 0.05), in: children who received antibiotics versus those who did not (9.5 days vs. 8); children &lt;5 years versus those over (9 days vs. 7); and children with chronic illnesses versus those without (9 days vs. 8). Conclusions Most children presenting to ED with ARI recover within 10 days. The length of recovery does not vary significantly by age, chronic illnesses, or antibiotic usage. Key messages Registry data provides baseline data to inform clinical trials assessing the role and duration of antibiotics for ARI.

Integrated mass spectrometry-based multi-omics for elucidating mechanisms of bacterial virulence

Despite being considered the simplest form of life, bacteria remain enigmatic, particularly in light of pathogenesis and evolving antimicrobial resistance. After three decades of genomics, we remain some way from understanding these organisms, and a substantial proportion of genes remain functionally unknown. Methodological advances, principally mass spectrometry (MS), are paving the way for parallel analysis of the proteome, metabolome and lipidome. Each provides a global, complementary assay, in addition to genomics, and the ability to better comprehend how pathogens respond to changes in their internal (e.g. mutation) and external environments consistent with infection-like conditions. Such responses include accessing necessary nutrients for survival in a hostile environment where co-colonizing bacteria and normal flora are acclimated to the prevailing conditions. Multi-omics can be harnessed across temporal and spatial (sub-cellular) dimensions to understand adaptation at the molecular level. Gene deletion libraries, in conjunction with large-scale approaches and evolving bioinformatics integration, will greatly facilitate next-generation vaccines and antimicrobial interventions by highlighting novel targets and pathogen-specific pathways. MS is also central in phenotypic characterization of surface biomolecules such as lipid A, as well as aiding in the determination of protein interactions and complexes. There is increasing evidence that bacteria are capable of widespread post-translational modification, including phosphorylation, glycosylation and acetylation; with each contributing to virulence. This review focuses on the bacterial genotype to phenotype transition and surveys the recent literature showing how the genome can be validated at the proteome, metabolome and lipidome levels to provide an integrated view of organism response to host conditions.

Significance of Sodium Bisulfate (SBS) Tempering in Reducing the Escherichia coli O121 and O26 Load of Wheat and Its Effects on Wheat Flour Quality

The occurrence of recalls involving pathogenic Escherichia coli-contaminated wheat flours show the need for incorporating antimicrobial interventions in wheat milling. The objectives of this study were to assess the efficacy of sodium bisulfate (SBS) tempering in reducing E. coli O121 (ATCC 2219) and O26 (ATCC 2196) wheat load and to evaluate the impact of effective (≥3.0 log reductions) SBS treatments on wheat flour quality. Wheat grains were inoculated with E. coli (~6 log CFU/g) and tempered (17% moisture, 24 h) using the following SBS concentrations (%wheat basis): 0, 0.5, 0.75, 1.0, 1.25, and 1.5% SBS. Reductions in E. coli O121 and O26 wheat load at different time intervals (0.5, 2, 6, 12, 18, and 24 h) during tempering were evaluated. The addition of SBS during tempering resulted in E. coli (O121 and O26) log reductions of 2.0 (0.5% SBS) to >4.0 logs (1.5% SBS) (p ≤ 0.05). SBS tempering (1.25 and 1.5% SBS) produced acidic wheat flours (pH = 4.51–4.60) but had comparable wheat flour properties in terms of composition, dough, and bread-making properties relative to the control (0% SBS). SBS tempering reduced the E. coli O121 and O26 load of wheat after tempering with minimal effects on wheat flour quality.

Application of peroxyacetic acid for decontamination of raw poultry products and comparison to other commonly used chemical antimicrobial interventions – A Review

Poultry remains one of the top food commodities responsible for foodborne illness in the U.S., despite poultry industry efforts since the inception of HACCP to reduce the burden of foodborne illness implicating poultry products. The appropriate use of antimicrobial compounds during processing of raw poultry can help minimize this risk. Currently, peroxyacetic acid (PAA) is the most popular antimicrobial in the poultry industry, displacing chlorine compounds and others. The aim of this review was to compare the effectiveness of PAA to that of other antimicrobials for the decontamination of raw poultry carcasses and parts. Twenty-six articles were found that compared PAA to over 20 different antimicrobials, applied as spray or immersion treatments for different exposure times and concentrations. The most common comparisons were to chlorine compounds (17 articles), to lactic acid (LA) compounds (5 articles) and to cetylpyridinium chloride (CPC, 6 articles). Studies measured effectiveness by reductions in native flora or inoculated bacteria, usually Salmonella or Campylobacter . PAA was found to be more effective than chlorine under most conditions studied. Effectiveness of PAA was higher or comparable to that of LA and CPC depending on product and treatment conditions. Overall, the results of primary literature studies support the popularity of PAA as an effective intervention against pathogenic bacteria during poultry processing.

Superhydrophobic Nanocoatings as Intervention against Biofilm-Associated Bacterial Infections

Biofilm formation represents a significant cause of concern as it has been associated with increased morbidity and mortality, thereby imposing a huge burden on public healthcare system throughout the world. As biofilms are usually resistant to various conventional antimicrobial interventions, they may result in severe and persistent infections, which necessitates the development of novel therapeutic strategies to combat biofilm-based infections. Physicochemical modification of the biomaterials utilized in medical devices to mitigate initial microbial attachment has been proposed as a promising strategy in combating polymicrobial infections, as the adhesion of microorganisms is typically the first step for the formation of biofilms. For instance, superhydrophobic surfaces have been shown to possess substantial anti-biofilm properties attributed to the presence of nanostructures. In this article, we provide an insight into the mechanisms underlying biofilm formation and their composition, as well as the applications of nanomaterials as superhydrophobic nanocoatings for the development of novel anti-biofilm therapies.

Effect of peroxyacetic acid spray and storage temperature on the microbiota and sensory properties of vacuum packed subprimal cuts

We investigated the impact of peroxyacetic acid (PAA; 200 ppm) spray on the microbiota and shelf life of commercial vacuum packed beef stored at chiller temperatures. Ribeye cuts (n=147) were collected from a local beef plant on the day of production for two consecutive days, with one set collected at the start of work with the PAA spray nozzles turned off (control) and during the routine production with the PAA spray nozzles turned on (PAA) on each day. Packs were stored at 4, 2 and -1°C for up to 34, 104 and 180 days, and sampled at appropriate intervals for sensory assessment, microbial enumeration and microbial profiling by 16S rRNA gene amplicon analysis. Treatment with PAA did not affect the initial meat pH, the initial numbers of total aerobes, lactic acid bacteria or Enterobacteriaceae (p>0.05) before storage; however, it delayed the onset of spoilage by 7, 21 and 54 days at 4, 2 and -1°C, respectively. Square root models of the variation of growth rate with temperature indicated lactic acid bacteria grew faster and Enterobacteriaceae grew slower on PAA treated than not treated meat. Negative associations between pH and deterioration of meat during storage were observed for PAA treated meat. During storage, the microbiota were primarily dominated by Carnobacterium and Lactobacillus/Lactococcus on control meat, but by Leuconostoc on PAA treated meat. Serratia, Yersinia and Clostridium were identified by LEfSe analysis as biomarkers for control meat, the latter of which was found in high abundance in samples that had the highest spoilage scores. IMPORTANCE The findings of this study show that PAA solutions applied at low concentrations under commercial settings positively modulated the meat microbiota. It did not have bactericidal effects for beef subprimals with very low microbial load. However, it differentially impacted the members of the microbiota, which resulted in delayed onset of spoilage of vacuum packed beef subprimal stored at all three temperatures (4, 2 and -1°C). This differential impact could be through one or a combination of the following factors: favoring the growth of lactic acid bacteria which may in turn exert a competitive exclusion that might be due to production of antimicrobial compounds such as organic acids and bacteriocins; exerting synergistic antimicrobial effects with low temperatures against members of Enterobacteriaceae; direct or indirect inhibitory effects against members of clostridia. These findings not only advance our understanding of the microbial ecology of vacuum packed meat stored at chiller temperatures, but also suggest bacteriostatic concentrations of antimicrobial interventions can be explored for shelf life extension.

Biofilm-forming capacity of Escherichia coli isolated from cattle and beef packing plants: relation to virulence attributes, stage of processing, antimicrobial interventions, and heat tolerance

Despite the importance of biofilm formation in contamination of meat by pathogenic Escherichia coli at slaughter plants, drivers for biofilm have been unclear. To identify selection pressures for biofilm, we evaluated 745 'Top 7' from cattle and 700 generic E. coli from two beef slaughter plants for motility, expression of curli and cellulose, and biofilm-forming potential. Top 7 were also screened for serogroup, stx1, stx2, eae and rpoS. Generic E. coli were compared by source (hide of carcass, hide-off carcass, processing equipment) before and after implementation of antimicrobial hurdles. The proportion of E. coli capable of forming biofilms was lowest (7.1%; P < 0.05) for cattle isolates and highest (87.3%; P < 0.05) from equipment. Only one enterohemorrhagic E. coli (EHEC) was an extremely-strong biofilm-former, in contrast to 73.4% of E. coli from equipment. Isolates from equipment after sanitation had a greater biofilm-forming capacity (P < 0.001) than those before sanitation. Most Top 7 were motile and expressed curli, although these traits along with expression of cellulose and presence of rpoS were not necessary for biofilm formation. In contrast, isolates capable of forming biofilms on equipment were almost exclusively motile and able to express curli. Results of the present study indicate that cattle would rarely carry EHEC capable of making strong biofilms to slaughter plants. However, if biofilm-forming EHEC contaminated equipment, current antimicrobial hurdles would inadvertently perpetuate the most robust biofilm-forming strains. Accordingly, new and effective anti-biofilm hurdles are required for meat-processing equipment, to reduce future instances of food-borne disease.

Dangerous Duplicity: The Dual Functions of Casein Kinase 1in Parasite Biology and Host Subversion

Casein Kinase 1 (CK1) family members are serine/threonine protein kinases that are involved in many biological processes and highly conserved in eukaryotes from protozoan to humans. Even though pathogens exploit host CK1 signaling pathways to survive, the role of CK1 in infectious diseases and host/pathogen interaction is less well characterized compared to other diseases, such as cancer or neurodegenerative diseases. Here we present the current knowledge on CK1 in protozoan parasites highlighting their essential role for parasite survival and their importance for host-pathogen interactions. We also discuss how the dual requirement of CK1 family members for parasite biological processes and host subversion could be exploited to identify novel antimicrobial interventions.