Case report of enterobacter hormaechei in sheep with respiratory disease and death

Next-Generation Sequencing-Based Identification of Enterobacter hormaechei as Causative Agent of High Mortality Disease in NOD.Cg-PrkdcscidIl2rgtm1Wjl/SzJ (NSG) Mice

NOD.Cg-PrkdcscidIl2rgtm1Wjl/SzJ (NSG) mice, lacking many components of a mature immune system, are at increased risk of disease. General understanding of potential pathogens of these mice is limited. We describe a high mortality disease outbreak caused by an opportunistic bacterial infection in NSG mice. Affected animals exhibited perianal fecal staining, dehydration, and wasting. Histopathologic lesions included a primary necrotizing enterocolitis, with inflammatory and necrotizing lesions also occurring in the liver, kidneys, heart, and brain of some mice. All affected individuals tested negative for known opportunistic pathogens of immunodeficient mice. We initially identified a member of Enterobacter cloacae complex (ECC) in association with the outbreak by traditional diagnostics. ECC was cultured from extraintestinal organs, both with and without histopathologic lesions, suggesting bacteremia. Infrared spectroscopy and MALDI-TOF mass spectrometry demonstrated that isolates from the outbreak shared molecular features and likely a common origin. We subsequently hypothesized that advanced sequencing methods would identify a single species of ECC associated with clinical disease. Using a novel targeted amplicon-based next-generation sequencing assay, we identified Enterobacter hormaechei in association with this outbreak. Knowledge of this organism as a potential opportunistic pathogen in NSG mice is critical for preclinical studies to prevent loss of animals and confounding of research.

Polystyrene microplastics biodegradation by gut bacterial Enterobacter hormaechei from mealworms under anaerobic conditions: Anaerobic oxidation and depolymerization

Synthetic plastic is used throughout daily life and industry, threatening organisms with microplastic pollution. Polystyrene is a major plastic polymer and also widely found sources of plastic wastes and microplastics. Here, we report that Enterobacter hormaechei LG3 (CP118279.1), a facultative anaerobic bacterial strain isolated from the gut of Tenebrio molitor larvae (mealworms) can oxidize and depolymerize polystyrene under anaerobic conditions. LG3 performed biodegradation while forming a biofilm on the plastic surface. PS biodegradation was characterized by analyses of surface oxidation, change in morphology and molecular weights, and production of biodegraded derivative. The biodegradation performance by LG3 was compared with PS biodegradation by Bacillus amyloliquefaciens SCGB1 under both anaerobic and aerobic conditions. In addition, through nanopore sequencing technology, we identified degradative enzymes, including thiol peroxidase (tpx), alkyl hydroperoxide reductase C (ahpC) and bacterioferritin comigratory protein (bcp). Along with the upregulation of degradative enzymes for biodegradation, changes in lipid A and biofilm-associated proteins were also observed after the cells were incubated with polystyrene microplastics. Our results provide evidence for anaerobic biodegradation by polystyrene-degrading bacteria and show alterations in gene expression patterns after polystyrene microplastics treatment in the opportunistic pathogen Enterobacter hormaechei.

Detection and Antimicrobial Resistance of Enterobacteriaceae other than Escherichia Coli in Raccoons from the Madrid Region of Spain

Introduction

Raccoons are an invasive alien species widely distributed in the Madrid region of Spain. These animals can carry a variety of enteric bacteria with associated antimicrobial resistance, which can infect humans and livestock. However, to our knowledge, the presence of non-E. coli Enterobacteriaceae in raccoons has not been previously studied.

Material and Methods

We conducted a study to examine the species distribution of Enterobacteriaceae isolates other than E. coli, as well as their antimicrobial resistance, in the faeces of 83 raccoons in the Madrid region.

Results

We detected 12 Enterobacteriaceae isolates other than E. coli belonging to seven different species: Citrobacter freundii (1 isolate), Citrobacter gillenii (3 isolates), Citrobacter murliniae (1 isolate), Citrobacter portucalensis (2 isolates), Enterobacter hormaechei subsp. hoffmannii (1 isolate), Hafnia paralvei (2 isolates) and Raoultella ornithinolytica (2 isolates). These isolates were found in 7 of the 83 (8.4%) animals studied. To our knowledge, this study is the first report of the presence of non-E. coli Enterobacteriaceae in raccoon faeces. All isolates but one were resistant to at least one of the 14 antimicrobials tested. Resistance to ampicillin (83.3%), amoxicillinclavulanic acid (50%) and cefoxitin (33.3%) was the most frequent.

Conclusion

Our study indicates that raccoons are a potential source of infection with Enterobacteriaceae other than E. coli for humans and livestock in the Madrid region.