Attachment of Enterohemorrhagic Escherichia coli to Host Cells Reduces O Antigen Chain Length at the Infection Site That Promotes Infection

Little is known about the regulation of cell wall structure of enteropathogenic bacteria within the host. Here, we report that enterohemorrhagic Escherichia coli regulates its cell wall structure during the infection process, which balances its survival in the intestinal lumen and infection of intestinal epithelial cells.

ZnO/Ag3PO4 and ZnO–Malachite as Effective Photocatalysts for the Removal of Enteropathogenic Bacteria, Dyestuffs, and Heavy Metals from Municipal and Industrial Wastewater

Different composites based on ZnO/Ag3PO4 and ZnO–malachite (Cu2(OH)2CO3) were synthesized in order to determine their effectiveness in the treatment of municipal and industrial wastewaters (mainly polluted by enteropathogenic bacteria, dyes, and heavy metals). The addition of Ag3PO4 and malachite did not significantly modify the physicochemical properties of ZnO; however, the optical properties of this oxide were modified as a result of its coupling with the modifiers. The modification of ZnO led to an improvement in its effectiveness in the treatment of municipal and industrial wastewater. In general, the amount of malachite or silver phosphate and the effluent to be treated were the determining factors in the effectiveness of the wastewater treatment. The highest degree of elimination of bacteria from municipal wastewater and discoloration of textile staining wastewater were achieved by using ZnO/Ag3PO4 (5%), but an increase in the phosphate content had a detrimental effect on the treatment. Likewise, the highest Fe and Cu photoreduction from coal mining wastewater was observed by using ZnO–malachite (2.5%) and ZnO/Ag3PO4 (10%), respectively. Some of the results of this work were presented at the fourth Congreso Colombiano de Procesos Avanzados de Oxidación (4CCPAOx).

Environmental Drivers of the Seasonal Prevalence of Enteropathogenic Bacteria in the Gulf Ecosystem of Gujarat, India: Unravelling Its Diarrheal Enigma

Recurrent episodes of water borne diarrheal outbreaks is the pressing public health crisis in the Gulf of Khambat (GoK), Gujarat and its adjoining area. We aimed to identify seasonality of environmental signatures associated with the dynamics of Gulf enteropathogens and related health implications. A yearlong sampling data has been generated from the five sites across the GoK of high anthropogenic burden and contrasting hydrological settings. Hydro-chemical characteristics of water samples and bacteriological indices were analysed on field and laboratory condition respectively and robust statistics was applied to assess their interrelationship and associated health risks. Annual variation of hydro-chemical indices viz. temperature 26.4oC–36.7oC, pH 7.51–8.44, salinity 28.3–36.7 mS/cm, turbidity 3.6–995 NTU and Dissolved Oxygen (DO) was recorded in the water samples. Extremely high turbidity (70.5-995) along with high salinity (28.3-34.8) is found to be the unique characteristic feature of Gulf water, which facilitates the abundance of various enteropathogenic bacterial species, specially the clinically important ones like V. cholerae, V. alginolyticus and E. coli. Surprisingly, an explosive annual preponderance of V. alginolyticus could be observed throughout all the study sites and existence of V. cholerae is restricted only in the high turbid water (>500NTU) of Gulf. Detection of E. coli is also a significant report from this high saline habitat, indicating faecal contamination. Seasonality of Vibrios and coliforms are highly influenced by precipitation rate and turbidity of water (p<0.05). DO level is found to be another crucial marker which regulates distribution of enteropathogens across the Gulf water as well as indicates the pollution level of Gulf attributed to environmental health risk. This is the first report of a longitudinal study of enteropathogenic load in GoK and its direct relationship with diarrheal incidence profile, which adds valuable knowledge for the formulation of ‘bio-environmental tool’ for effective water quality monitoring and disease prevention.

Feedborne Salmonella enterica Serovar Jerusalem Outbreak in Different Organic Poultry Flocks in Switzerland and Italy Linked to Soya Expeller

Poultry feed is a leading source of Salmonella infection in poultry. In Switzerland, heat-treated feed is used to reduce Salmonella incursions into flocks in conventional poultry production. By contrast, organic feed is only treated with organic acids. In 2019, the Swiss National Reference Center for Enteropathogenic Bacteria identified the rare serovar S. Jerusalem from samples of organic soya feed. Further, in July 2020, the European Union’s Rapid Alert System for Food and Feed published a notification of the detection of S. Jerusalem in soya expeller from Italy. During 2020, seven S. Jerusalem isolates from seven different poultry productions distributed over six cantons in Switzerland were reported, providing further evidence of a possible outbreak. Using whole-genome sequencing (WGS), S. Jerusalem isolates from feed and from animals in Switzerland were further characterized and compared to S. Jerusalem from organic poultry farm environments in Italy. WGS results showed that feed isolates and isolates from Swiss and Italian poultry flocks belonged to the sequence type (ST)1028, grouped in a very tight cluster, and were closely related. This outbreak highlights the risk of spreading Salmonella by feed and emphasizes the need for a heat-treatment process for feed, also in organic poultry production.

Phosphatidylinositol 3-kinase-independent synthesis of PtdIns(3,4)P2 by a phosphotransferase

Despite their comparatively low abundance, phosphoinositides play a central role in membrane traffic and signalling. PtdIns(3,4,5)P3 and PtdIns(3,4)P2 are uniquely important, as they promote cell growth, survival, and migration. Pathogenic organisms have developed means to subvert phosphoinositide metabolism to promote successful infection and their survival within host organisms. We demonstrate that PtdIns(3,4)P2 is generated in host cells by effectors of the enteropathogenic bacteria Salmonella and Shigella. Pharmacological, gene silencing and heterologous expression experiments revealed that, remarkably, the biosynthesis of PtdIns(3,4)P2 occurs independently of phosphoinositide 3-kinases. Instead, we found that the Salmonella effector SopB, heretofore believed to be a phosphatase, generates PtdIns(3,4)P2 de novo via a phosphotransferase/phosphoisomerase mechanism. Recombinant SopB is capable of generating PtdIns(3,4)P2 from PtdIns(4,5)P2 in a cell-free system. Through a remarkable instance of convergent evolution, bacterial effectors acquired the ability to synthesize 3-phosphorylated phosphoinositides by an ATP- and kinase-independent mechanism, thereby subverting host signaling to gain entry and even provoke oncogenic transformation.

Phosphatidylinositol 3-kinase-independent synthesis of PtdIns(3,4)P2 by a phosphotransferase

Despite their comparatively low abundance, phosphoinositides play a central role in membrane traffic and signalling. PtdIns(3,4,5)P3 and PtdIns(3,4)P2 are uniquely important, as they promote cell growth, survival, and migration. Pathogenic organisms have developed means to subvert phosphoinositide metabolism to promote successful infection and their survival within host organisms. We demonstrate that PtdIns(3,4)P2 is generated in host cells by effectors of the enteropathogenic bacteria Salmonella and Shigella. Pharmacological, gene silencing and heterologous expression experiments revealed that, remarkably, the biosynthesis of PtdIns(3,4)P2 occurs independently of phosphoinositide 3-kinases. Instead, we found that the Salmonella effector SopB, heretofore believed to be a phosphatase, generates PtdIns(3,4)P2 de novo via a phosphotransferase/phosphoisomerase mechanism. Recombinant SopB is capable of generating PtdIns(3,4)P2 from PtdIns(4,5)P2 in a cell-free system. Through a remarkable instance of convergent evolution, bacterial effectors acquired the ability to synthesize 3-phosphorylated phosphoinositides by an ATP- and kinase-independent mechanism, thereby subverting host signaling to gain entry and even provoke oncogenic transformation.

Lyophilized alginate-based microspheres containing Lactobacillus fermentum D12, an exopolysaccharides producer, contribute to the strain’s functionality in vitro

Lactobacillus (Limosilactobacillus) fermentum D12 is an exopolysaccharide (EPS) producing strain whose genome contains a putative eps operon. Whole-genome analysis of D12 was performed to disclose the essential genes correlated with activation of precursor molecules, elongation and export of the polysaccharide chain, and regulation of EPS synthesis. These included the genes required for EPS biosynthesis such as epsA, B, C, D and E, also gt, wzx, and wzy and those involved in the activation of the precursor molecules galE, galT and galU. Both the biosynthesis and export mechanism of EPS were proposed based on functional annotation. When grown on MRS broth with an additional 2% w/v glucose, L. fermentum D12 secreted up to 200 mg/L of a mixture of EPSs, whose porous structure was visualized by scanning electron microscopy (SEM). Structural information obtained by 1HNMR spectroscopy together with composition and linkage analyses, suggested the presence of at least two different EPSs, a branched heteropolysaccharide containing t-Glcp and 2,6-linked Galf, and glycogen. Since recent reports showed that polysaccharides facilitate the probiotic-host interactions, we at first sought to evaluate the functional potential of L. fermentum D12. Strain D12 survived simulated gastrointestinal tract (GIT) conditions, exhibited antibacterial activity against enteropathogenic bacteria, adhered to Caco-2 cells in vitro, and as such showed potential for in vivo functionality. The EPS crude extract positively influenced D12 strain capacity to survive during freeze-drying and to adhere to extracellular matrix (ECM) proteins but did not interfere Caco-2 and mucin adherence when added at concentrations of 0.2, 0.5, and 1.0 mg/mL. Since the viable bacterial count of free D12 cells was 3 logarithmic units lower after the exposure to simulated GIT conditions than the initial count, the bacterial cells had been loaded into alginate for viability improvement. Microspheres of D12 cells, which were previously analyzed at SEM, significantly influenced their survival during freeze-drying and in simulated GIT conditions. Furthermore, the addition of the prebiotic substrates mannitol and lactulose improved the viability of L. fermentum D12 in freeze-dried alginate microspheres during 1-year storage at 4 °C compared to the control.

Enteropathogenic Bacterial and Intestinal Parasitic Infections among Asymptomatic Food Handlers in Rangsit University Canteens, Central Thailand

Food handlers play an important role in the transmission of foodborne diseases. 108 asymptomatic food handlers work in RSU canteens and have never been checked for intestinal bacteria and parasites, which might be a potential source of infection for customers. This study is aimed at estimating the prevalence of enteropathogenic bacterial and intestinal parasitic infections among food handlers in Rangsit University canteens, central Thailand. A total of 79 food handlers were enrolled, and each provided one stool sample (response rate of 73.2%). Females comprised 93.7% of study participants, and the largest age group was 41–50 years (34.2%). The prevalence of enteropathogenic bacteria in stool cultures was 2.5%, and only Aeromonas spp. were detected. The pathogenic protozoa Giardia duodenalis was detected in 1.3% of samples, and nonpathogenic protozoa was found in 11.4%. No helminths were found in any samples. Approximately 80% of food handlers demonstrated good hygiene practices, including regular hand washing after visiting the toilet, regular hand washing when preparing food, using soap when washing hands, wearing uniforms/gowns, practicing correct hand washing techniques, and having short fingernails. However, the results showed a lack of personal hygiene training and routine medical care (>50% of samples). Stronger intervention would help to eliminate future infections.