Invasive listeriosis outbreaks and salmon products: a genomic, epidemiological study.

Invasive listeriosis, caused by , is a severe foodborne infection, especially for immunocompromised individuals. The aim of our investigation was the identification and analysis of listeriosis outbreaks in Germany with smoked and graved salmon products as the most likely source of infection using whole-genome sequencing (WGS) and patient interviews. In a national surveillance programme, WGS was used for subtyping and core genome multi locus sequence typing (cgMLST) for cluster detection of isolates from listeriosis cases as well as food and environmental samples in Germany.

Nationwide outbreak of invasive listeriosis associated with consumption of meat products in health care facilities, Germany, 2014-2019.

Objectives: Invasive listeriosis is a severe foodborne infection caused by Listeria(L.)monocytogenes. The aim of this investigation was to verify and describe a molecular cluster of listeriosis patients and identify factors leading to this outbreak.

A Phosphatidylinositol 3-Kinase Effector Alters Phagosomal Maturation to Promote Intracellular Growth of Francisella.

Many pathogenic intracellular bacteria manipulate the host phago-endosomal system to establish and maintain a permissive niche. The fate and identity of these intracellular compartments is controlled by phosphoinositide lipids. By mechanisms that have remained undefined, a Francisella pathogenicity island-encoded secretion system allows phagosomal escape and replication of bacteria within host cell cytoplasm.

Combinations of mutations in envZ, ftsI, mrdA, acrB and acrR can cause high-level carbapenem resistance in Escherichia coli.

Objectives: The worldwide spread of ESBL-producing Enterobacteriaceae has led to an increased use of carbapenems, the group of β-lactams with the broadest spectrum of activity. Bacterial resistance to carbapenems is mainly due to acquired carbapenemases or a combination of ESBL production and reduced drug influx via loss of outer-membrane porins. Here, we have studied the development of carbapenem resistance in Escherichia coli in the absence of β-lactamases.

Silver resistance genes are overrepresented among Escherichia coli isolates with CTX-M production.

Members of the Enterobacteriaceae with extended-spectrum beta-lactamases (ESBLs) of the CTX-M type have disseminated rapidly in recent years and have become a threat to public health. In parallel with the CTX-M type expansion, the consumption and widespread use of silver-containing products has increased. To determine the carriage rates of silver resistance genes in different Escherichia coli populations, the presence of three silver resistance genes (silE, silP, and silS) and genes encoding CTX-M-, TEM-, and SHV-type enzymes were explored in E.

High fitness costs and instability of gene duplications reduce rates of evolution of new genes by duplication-divergence mechanisms.

An important mechanism for generation of new genes is by duplication-divergence of existing genes. Duplication-divergence includes several different submodels, such as subfunctionalization where after accumulation of neutral mutations the original function is distributed between two partially functional and complementary genes, and neofunctionalization where a new function evolves in one of the duplicated copies while the old function is maintained in another copy. The likelihood of these mechanisms depends on the longevity of the duplicated state, which in turn depends on the fitness cost and genetic stability of the duplications.

Frequent emergence of porin-deficient subpopulations with reduced carbapenem susceptibility in ESBL-producing Escherichia coli during exposure to ertapenem in an in vitro pharmacokinetic model.

Objectives: Ertapenem resistance is increasing in Enterobacteriaceae. The production of extended-spectrum β-lactamases (ESBLs) and reduced expression of outer membrane porins are major mechanisms of resistance in ertapenem-resistant Klebsiella pneumoniae. Less is known of ertapenem resistance in Escherichia coli.

Influence of acquired β-lactamases on the evolution of spontaneous carbapenem resistance in Escherichia coli.

Objectives: To investigate the influence of plasmid-borne β-lactamases on the evolution of spontaneous carbapenem resistance in Escherichia coli and the fitness costs associated with resistance.

Methods: Stepwise selection of carbapenem-resistant mutants with or without the extended-spectrum β-lactamase (ESBL)-encoding plasmid pUUH239.2 was performed.