Functional characterization of a miniature inverted transposable element at the origin of mcr-5 gene acquisition in Escherichia coli

Plasmid-mediated colistin resistance of the mobile colistin resistance (MCR) type is a growing concern in Enterobacteriaceae since it has been described worldwide in humans and animals. Here, we identified a series of MCR-producing Escherichia coli isolates corresponding to two different clones (represented by isolates PS1 and PS8b) producing MCR-1 and MCR-5, respectively, obtained from pig fecal samples in France. Plasmid analysis showed that the plasmid carrying the mcr-1 gene (pPS1) possesses an IncHI2 backbone, whereas the mcr-5 gene was carried onto a 6,268-bp nontypeable non-self-conjugative plasmid (pPS8b). Detailed analysis of plasmid pPS8b revealed a 3,803-bp-long cassette containing the mcr-5 gene that was bracketed by two inverted-repeat (IR) sequences with 5-bp-long direct repeats at each extremity, similarly to an insertion sequence, but with the exception that no transposase gene was identified within this cassette. By performing in vitro transposition experiments, we showed that the mcr-5 cassette could be mobilized by the TnAs1 transposase provided in trans, displaying a mobilization mechanism similar to that of miniature inverted-repeat transposable elements (MITEs)

Rapid polymyxin NP test for the detection of polymyxin resistance mediated by the MCR-1/MCR-2 genes

The Rapid Polymyxin NP test has been recently developed to rapidly detect polymyxin resistance in Enterobacteriaceae. Here we evaluated this test for detecting MCR- 1/MCR-2-producing Enterobacteriaceae using a collection of 70 non-redundant strains either recovered from the environment, animals, or humans. Sensitivity and specificity were found to be 100%

Characterization of a new mutation (R292G) and a deletion at the human uroporphyrinogen decarboxylase locus in two patients with hepatoerythropoietic porphyria

A deficiency in the activity of uroporphyrinogen decarboxylase (UROD), the fifth enzyme of the haem biosynthetic pathway, is found in familial porphyria cutanea tarda (F-PCT) and hepatoerythropoietic porphyria (HEP). A new mutation (R292G) and a deletion have been found in a pedigree with two HEP patients (two sisters). The R292G mutation was not detected in 13 unrelated affected patients with F-PCT, so it appears to be uncommon. The possibility that the arginine 292 may participate at the active site of the enzyme is discussed. A summary of the 7 mutations/deletions found in the UROD gene with their frequency is presented

A Telemonitoring and Hybrid Virtual Coaching Solution “CAir” for Patients with Chronic Obstructive Pulmonary Disease: Protocol for a Randomized Controlled Trial

Background: Chronic obstructive pulmonary disease (COPD) is one of the most common disorders in the world. COPD is characterized by airflow obstruction, which is not fully reversible. Patients usually experience breathing-related symptoms with periods of acute worsening and a substantial decrease in the health-related quality-of-life. Active and comprehensive disease management can slow down the progressive course of the disease and improve patients’ disabilities. Technological progress and digitalization of medicine have the potential to make elaborate interventions easily accessible and applicable to a broad spectrum of patients with COPD without increasing the costs of the intervention. Objective: This study aims to develop a comprehensive telemonitoring and hybrid virtual coaching solution and to investigate its effects on the health-related quality of life of patients with COPD. Methods: A monocentric, assessor-blind, two-arm (intervention/control) randomized controlled trial will be performed. Participants randomized to the control group will receive usual care and a CAir Desk (custom-built home disease-monitoring device to telemonitor disease-relevant parameters) for 12 weeks, without feedback or scores of the telemonitoring efforts and virtual coaching. Participants randomized to the intervention group will receive a CAir Desk and a hybrid digital coaching intervention for 12 weeks. As a primary outcome, we will measure the delta in the health-related quality of life, which we will assess with the St. George Respiratory Questionnaire, from baseline to week 12 (the end of the intervention). Results: The development of the CAir Desk and virtual coach has been completed. Recruitment to the trial started in September 2020. We expect to start data collection by December 2020 and expect it to last for approximately 18 months, as we follow a multiwave approach. We expect to complete data collection by mid-2022 and plan the dissemination of the results subsequently. Conclusions: To our knowledge, this is the first study investigating a combination of telemonitoring and hybrid virtual coaching in patients with COPD. We will investigate the effectiveness, efficacy, and usability of the proposed intervention and provide evidence to further develop app-based and chatbot-based disease monitoring and interventions in COPD

IncH-type plasmid harboring the blaCTX-M-15, blaDHA-1, and qnrB4 genes recovered from animal isolates

The whole sequence of plasmid pENVA carrying the extended-spectrum ß-lactamase gene blaCTX-M-15 was determined. It has been identified from a series of clonally-related Klebsiella pneumoniae ST274 strains recovered from companion animals. This plasmid was 253,984-bp in-size and harbored, in addition to blaCTX-M-15, a large array of genes encoding resistance to many antibiotic molecules including β-lactams (blaTEM-1, blaDHA-1), aminoglycosides (aacA2, aadA1), tetracycline (tetA), quinolones (qnrB4), trimethoprim (dfrA15), and sulfonamides (two copies of sul1). In addition, genes encoding resistance to mercury, tellurium, nickel, and quaternary compounds were identified. In addition, it carried genes encoding for DNA damage protection and mutagenesis repair, and also a CRISPR system locus corresponding to a immune system protecting against bacteriophages and plasmids. Comparative analysis of the plasmid scaffold showed that it possessed a similar structure with only a single plasmid, being pNDM-MAR encoding the carbapenemase NDM-1 and identified from human K. pneumoniae isolates. Both plasmids possessed two replicons, namely those of IncFIB-like and IncHIB-like plasmids, being significantly different from the previously characterized. The blaCTX-M-15 gene, together with the other antibiotic resistance genes, was part of a large module likely acquired through a transposition process. We characterized here a new plasmid type encompassing the blaCTX-M-15 gene identified in a K. pneumoniae of animal origin. It remains to determine to which extend this plasmid type may spread efficiently, and possibly further enhance the dissemination of blaCTX-M-15 among animal and human isolates

Harderoporphyria: a variant hereditary coproporphyria.

Three siblings with intense jaundice and hemolytic anemia at birth were found to excrete a high level of coproporphyrin in their urine and feces; the pattern of fecal porphyrin excretion was atypical for hereditary coproporphyria because the major porphyrin was harderoporphyrin (greater than 60%; normal value is less than 20%). The lymphocyte coproporphyrinogen III oxidase activity of each patient was 10% of control values, which suggests a homozygous state. Both parents showed only mild abnormalities in porphyrin excretion and lymphocyte coproporphyrinogen III oxidase activity decreased to 50% of normal values, as is expected in heterozygous cases of hereditary coproporphyria. Kinetic parameters of coproporphyrinogen III oxidase from these patients were clearly modified, with a Michaelis constant 15-20-fold higher than normal values when using coproporphyrinogen or harderoporphyrinogen as substrates. Maximal velocity was half the normal value, and we also observed a marked sensitivity to thermal denaturation. The possibility that a mutation affecting the enzyme on the active center which is specifically involved in the second decarboxylation (from harderoporphyrinogen to protoporphyrinogen) was eliminated by experiments on rat liver that showed that coproporphyrinogen and harderoporphyrinogen were metabolized at the same active center. The pattern of porphyrin excretion and the coproporphyrinogen oxidase from the three patients exhibited abnormalities that were different from the abnormalities found in another recently described homozygous case of hereditary coproporphyria. We suggest naming this variant of coproporphyrinogen oxidase defect "harderoporphyria.