Use of Fly Screens to Reduce Campylobacter spp. Introduction in Broiler Houses

Fly screens that prevented influx of flies in 20 broiler houses during the summer of 2006 in Denmark caused a decrease in Campylobacter spp.–positive flocks from 51.4% in control houses to 15.4% in case houses. A proportional reduction in the incidence of chicken-borne campylobacteriosis can be expected by comprehensive intervention against flies in broiler production houses

SERS detection of the biomarker hydrogen cyanide from <em>Pseudomonas aeruginosa</em> cultures isolated from cystic fibrosis patients

Pseudomonas aeruginosa is the primary cause of chronic airway infections in cystic fibrosis (CF) patients. Persistent infections are seen from the first P. aeruginosa culture in about 75% of young CF patients, and it is important to discover new ways to detect P. aeruginosa at an earlier stage. The P. aeruginosa biomarker hydrogen cyanide (HCN) contains a triple bond, which is utilized in this study because of the resulting characteristic C≡N peak at 2135 cm(−1) in a Raman spectrum. The Raman signal was enhanced by surface-enhanced Raman spectroscopy (SERS) on a Au-coated SERS substrate. After long-term infection, a mutation in the patho-adaptive lasR gene can alter the expression of HCN, which is why it is sometimes not possible to detect HCN in the breath of chronically infected patients. Four P. aeruginosa reference strains and 12 clinical P. aeruginosa strains isolated from CF children were evaluated, and HCN was clearly detected from overnight cultures of all wild type-like isolates and half of the later isolates from the same patients. The clinical impact could be that P. aeruginosa infections could be detected at an earlier stage, because daily breath sampling with an immediate output could be possible with a point-of-care SERS device

Phylogeny of the Viral Hemorrhagic Septicemia Virus in European Aquaculture

<p>One of the most valuable aquaculture fish in Europe is the rainbow trout, Oncorhynchus mykiss, but the profitability of trout production is threatened by a highly lethal infectious disease, viral hemorrhagic septicemia (VHS), caused by the VHS virus (VHSV). For the past few decades, the subgenogroup Ia of VHSV has been the main cause of VHS outbreaks in European freshwater-farmed rainbow trout. Little is currently known, however, about the phylogenetic radiation of this Ia lineage into subordinate Ia clades and their subsequent geographical spread routes. We investigated this topic using the largest Ia-isolate dataset ever compiled, comprising 651 complete G gene sequences: 209 GenBank Ia isolates and 442 Ia isolates from this study. The sequences come from 11 European countries and cover the period 1971-2015. Based on this dataset, we documented the extensive spread of the Ia population and the strong mixing of Ia isolates, assumed to be the result of the Europe-wide trout trade. For example, the Ia lineage underwent a radiation into nine Ia clades, most of which are difficult to allocate to a specific geographic distribution. Furthermore, we found indications for two rapid, large-scale population growth events, and identified three polytomies among the Ia clades, both of which possibly indicate a rapid radiation. However, only about 4% of Ia haplotypes (out of 398) occur in more than one European country. This apparently conflicting finding regarding the Europe-wide spread and mixing of Ia isolates can be explained by the high mutation rate of VHSV. Accordingly, the mean period of occurrence of a single Ia haplotype was less than a full year, and we found a substitution rate of up to 7.813 × 10^-4 nucleotides per site per year. Finally, we documented significant differences between Germany and Denmark regarding their VHS epidemiology, apparently due to those countries' individual handling of VHS.</p

Longitudinal Evolution of the Pseudomonas-Derived Cephalosporinase (PDC) Structure and Activity in a CysticFibrosis Patient Treated with b-Lactams

Traditional studies on the evolution of antibiotic resistance development use approaches that can range from laboratory-based experimental studies, to epidemiological surveillance, to sequencing of clinical isolates. However, evolutionary trajectories also depend on the environment in which selection takes place, compelling the need to more deeply investigate the impact of environmental complexities and their dynamics over time. Herein, we explored the within-patient adaptive long-term evolution of a Pseudomonas aeruginosa hypermutator lineage in the airways of a cystic fibrosis (CF) patient by performing a chronological tracking of mutations that occurred in different subpopulations; our results demonstrated parallel evolution events in the chromosomally encoded class C β-lactamase (blaPDC). These multiple mutations within blaPDC shaped diverse coexisting alleles, whose frequency dynamics responded to the changing antibiotic selective pressures for more than 26 years of chronic infection. Importantly, the combination of the cumulative mutations in blaPDC provided structural and functional protein changes that resulted in a continuous enhancement of its catalytic efficiency and high level of cephalosporin resistance. This evolution was linked to the persistent treatment with ceftazidime, which we demonstrated selected for variants with robust catalytic activity against this expanded-spectrum cephalosporin. A “gain of function” of collateral resistance toward ceftolozane, a more recently introduced cephalosporin that was not prescribed to this patient, was also observed, and the biochemical basis of this cross-resistance phenomenon was elucidated. This work unveils the evolutionary trajectories paved by bacteria toward a multidrug-resistant phenotype, driven by decades of antibiotic treatment in the natural CF environmental setting. IMPORTANCE Antibiotics are becoming increasingly ineffective to treat bacterial infections. It has been consequently predicted that infectious diseases will become the biggest challenge to human health in the near future. Pseudomonas aeruginosa is considered a paradigm in antimicrobial resistance as it exploits intrinsic and acquired resistance mechanisms to resist virtually all antibiotics known. AmpC β-lactamase is the main mechanism driving resistance in this notorious pathogen to β-lactams, one of the most widely used classes of antibiotics for cystic fibrosis infections. Here, we focus on the β-lactamase gene as a model resistance determinant and unveil the trajectory P. aeruginosa undertakes on the path toward a multidrug-resistant phenotype during the course of two and a half decades of chronic infection in the airways of a cystic fibrosis patient. Integrating genetic and biochemical studies in the natural environment where evolution occurs, we provide a unique perspective on this challenging landscape, addressing fundamental molecular mechanisms of resistance.Fil: Colque, Claudia A. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Química Biológica; Argentina.Fil: Albarracín Orio, Andrea G. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Química Biológica; Argentina.Fil: Hedemann, Laura G. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Química Biológica; Argentina.Fil: Feliziani, Sofía. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Química Biológica; Argentina.Fil: Moyano, Alejandro J. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Química Biológica; Argentina.Fil: Smania, Andrea M. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Química Biológica; Argentina.Fil: Colque, Claudia A. Universidad Nacional de Córdoba. Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC-CONICET); Argentina.Fil: Albarracín Orio, Andrea G. Universidad Nacional de Córdoba. Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC-CONICET); Argentina.Fil: Hedemann, Laura G. Universidad Nacional de Córdoba. Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC-CONICET); Argentina.Fil: Feliziani, Sofía. Universidad Nacional de Córdoba. Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC-CONICET); Argentina.Fil: Moyano, Alejandro J. Universidad Nacional de Córdoba. Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC-CONICET); Argentina.Fil: Smania, Andrea M. Universidad Nacional de Córdoba. Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC-CONICET); Argentina.Fil: Tomatis, Pablo E. Universidad Nacional de Rosario. Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET); Argentina.Fil: Dotta, Gina. Universidad Nacional de Rosario. Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET); Argentina.Fil: Vila, Alejandro J. Universidad Nacional de Rosario. Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET); Argentina.Fil: Tomatis, Pablo E. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; Argentina.Fil: Moreno, Diego M. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; Argentina.Fil: Vila, Alejandro J. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; Argentina.Fil: Albarracín Orio, Andrea G. Universidad Católica de Córdoba. Facultad de Ciencias Agropecuarias. (IRNASUS-CONICET); Argentina.Fil: Moreno, Diego M. Universidad Nacional de Rosario. Instituto de Química de Rosario (IQUIR-CONICET); Argentina.Fil: Hickman Rachel A. Department of Clinical Microbiology; Denmark.Fil: Sommer, Lea M. Department of Clinical Microbiology; Denmark.Fil: Johansen, Helle K. Department of Clinical Microbiology; Denmark.Fil: Hickman Rachel A. Technical University of Denmark, Lyngb. Novo Nordisk Foundation Centre for Biosustainability; Denmark.Fil: Sommer, Lea M. Technical University of Denmark, Lyngb. Novo Nordisk Foundation Centre for Biosustainability; Denmark.Fil: Johansen, Helle K. Technical University of Denmark, Lyngb. Novo Nordisk Foundation Centre for Biosustainability; Denmark.Fil: Bonomo, Robert A. Case Western Reserve University. Departments of Molecular Biology and Microbiology, Medicine, Biochemistry, Pharmacology, and Proteomics and Bioinformatics; United States.Fil: Bonomo, Robert A. Senior Clinical Scientist Investigator. Louis Stokes Cleveland Department of Veterans Affairs; United States.Fil: Johansen, Helle K. University of Copenhagen. Department of Clinical Medicine; Denmark