Potential Impact of the Resistance to Quaternary Ammonium Disinfectants on the Persistence of Listeria monocytogenes in Food Processing Environments

The persistence of certain strains of Listeria monocytogenes, even after the food processing environment has been cleaned and disinfected, suggests that this may be related to phenomena that reduce the concentration of the disinfectants to subinhibitory levels. This includes (i) the existence of environmental niches or reservoirs that are difficult for disinfectants to reach, (ii) microorganisms that form biofilms and create microenvironments in which adequate concentrations of disinfectants cannot be attained, and (iii) the acquisition of resistance mechanisms in L. monocytogenes, including those that lead to a reduction in the intracellular concentration of the disinfectants. The only available data with regard to the resistance of L. monocytogenes to disinfectants applied in food production environments refer to genotypic resistance to quaternary ammonium compounds (QACs). Although there are several well-characterized efflux pumps that confer resistance to QACs, it is a low-level resistance that does not generate resistance to QACs at the concentrations applied in the food industry. However, dilution in the environment and biodegradation result in QAC concentration gradients. As a result, the microorganisms are frequently exposed to subinhibitory concentrations of QACs. Therefore, the low-level resistance to QACs in L. monocytogenes may contribute to its environmental adaptation and persistence. In fact, in certain cases, the relationship between low-level resistance and the environmental persistence of L. monocytogenes in different food production chains has been previously established. The resistant strains would have survival advantages in these environments over sensitive strains, such as the ability to form biofilms in the presence of increased biocide concentrations.The authors were supported by grants RTA2011-00098-C02 and RTA2014-00045-C03 (Ministry of Economy and Competitiveness, Spain, Plan Nacional I+D+i co-financed by INIA and FEDER) during the preparation of this manuscript.S

Whole-Genome Sequences of Seven Listeria monocytogenes Strains from Different Stages of a Poultry Meat Production Chain

Here, we present the draft genome sequences of seven Listeria monocytogenes strains isolated during three independent studies carried out in three stages of a poultry meat production chain. The genome sequences of these strains obtained from different stages can help to understand the possible transmission of L. monocytogenes.This work was supported in part by research project grant RTA2014-00045-C03 (INIA FEDER) from the Spanish Ministry of Science, Innovation and Universities. The support of the company Nutreco is also acknowledged. We thank the Unidad de Genómica (Instituto de Salud Carlos III, Majadahonda, Madrid, Spain) and Pilar López (Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Madrid, Spain) for technical assistance.S

Prevalence and Population Diversity of Listeria monocytogenes Isolated from Dairy Cattle Farms in the Cantabria Region of Spain

Listeria monocytogenes is an opportunistic pathogen that is widely distributed in the environment. Here we show the prevalence and transmission of L. monocytogenes in dairy farms in the Cantabria region, on the northern coast of Spain. A total of 424 samples was collected from 14 dairy farms (5 organic and 9 conventional) and 211 L. monocytogenes isolates were recovered following conventional microbiological methods. There were no statistically significant differences in antimicrobial resistance ratios between organic and conventional farms. A clonal relationship among the isolates was assessed by pulsed field gel electrophoresis (PFGE) analysis and 64 different pulsotypes were obtained. Most isolates (89%, n = 187) were classified as PCR serogroup IVb by using a multiplex PCR assay. In this case, 45 isolates of PCR serogroup IVb were whole genome-sequenced to perform a further analysis at genomic level. In silico MLST analysis showed the presence of 12 sequence types (ST), of which ST1, ST54 and ST666 were the most common. Our data indicate that the environment of cattle farms retains a high incidence of L. monocytogenes, including subtypes involved in human listeriosis reports and outbreaks. This pathogen is shed in the feces and could easily colonize dairy products, as a result of fecal contamination. Effective herd and manure management are needed in order to prevent possible outbreaks.This work was supported by Research Project grants RTA08-099, RTA2008-00080-C02, RTA2014-00045-C03-01 (INIA and FEDER) from the Spanish Ministry of Economy and Competitiveness and RTI2018-098267-R-C31 (INIA and FEDER) from the Spanish Ministry of Science and Innovation.S

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Análisis molecular de la resistencia a cloranfenicol en "Bacteroides" del grupo "fragilis"

Tesis doctoral inédita leida en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Biología Molecular. Fecha de lectura: 25 de Marzo de 198

Genome Sequences of Five Disinfectant-Resistant Listeria monocytogenes Strains from Two Iberian Pork-Processing Plants

We announce the draft genome sequences of five Listeria monocytogenes strains from two Iberian pork-processing plants located in Spain that were distinguished by their resistance to benzalkonium chloride. These strains seem highly adapted to the meat-processing environment according to their persistence and transmission capabilities.This work was sustained by funding from the Research Project grant RTA2011-00098-C02 (INIA FEDER) from the Spanish Ministry of Economy and Competitiveness. We gratefully acknowledge Pilar López (Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Madrid, Spain) for technical assistance.S

[La patogenicidad de Cronobacter a la luz de la genómica bacteriana]

7 Pág.Cronobacter spp. is a genus of Gram-negative bacteria belonging to the family Enterobacteriaceae. Species of the genus Cronobacter, particularly C. sakazakii, are implicated in the development of severe disease in newborns, which occurs with necrotizing enterocolitis, sepsis and meningitis. The disease has been frequently associated with powdered infant formula (PIF) and can therefore occur in the form of outbreaks. The genus Cronobacter has undergone extensive diversification in the course of its evolution, with some species being clearly pathogenic to humans while the impact of other species on human health is uncertain or unknown. Whole genome sequencing is used both in population genetic studies to identify the limited number of genotypes associated with the disease and to detect genes associated with antibiotic resistance or virulence, ultimately allowing more precise epidemiological links to be established between pediatric disease and infant foods.Cronobacter es un género de bacterias gramnegativas perteneciente a la familia Enterobacteriaceae. Algunas especies del género Cronobacter, en particular C. sakazakii, están implicadas en el desarrollo de infecciones neonatales graves, incluyendo meningitis, sepsis y enterocolitis necrotizante. La enfermedad se ha relacionado frecuentemente con los preparados en polvo para lactantes (PPL) y se puede presentar, por tanto, en forma de brotes. El género Cronobacter ha experimentado una amplia diversificación en el curso de su evolución, siendo algunas especies claramente patógenas para los humanos mientras que el impacto de otras especies sobre la salud humana es incierto o desconocido. La secuenciación genómica se utiliza en los estudios de genética de poblaciones tanto para identificar el limitado número de genotipos asociados a la enfermedad como para detectar los genes asociados a la virulencia, la adaptación al estrés o la resistencia a antibióticos, lo que permite, en definitiva, establecer vínculos epidemiológicos más precisos entre la enfermedad pediátrica y los alimentos infantiles.Este estudio ha sido financiado por el Proyecto RTI2018-098267-R-C31 del Ministerio de Ciencia e Innovación de EspañaPeer reviewe

Sequencing and heterologous expression in Saccharomyces cerevisiae of a Cryptococcus neoformans cDNA encoding a plasma membrane H+-ATPase

A cDNA containing an open reading frame encoding a putative plasma membrane H+-ATPase in the human pathogenic basidiomycetous yeast Cryptococcus neoformans was cloned and sequenced by means of PCR and cDNA library hybridization. The cloned cDNA is 3475 bp in length, containing a 2994 bp open reading frame encoding a polypeptide of 997 amino acids. As in the case of another basidiomycetous fungus (Uromyces fabae), the deduced amino acid sequence of CnPMA1 was found to be more homologous to those of P-type H+-ATPases from higher plants than to those from ascomycetous fungi. In order to prove the sequenced cDNA corresponds to a H+-ATPase, it was expressed in Saccharomyces cerevisiae and found to functionally replace its own H+-ATPase. Kinetic studies of CnPMA1 compared to ScPMA1 show differences in V(max) values and H+-pumping in reconstituted vesicles. The pH optimum and K(m) values are similar in both enzymes. (C) 2000 Elsevier Science B.V.This work was supported by the Spanish D.G.I.C.Y.T. (Grant PB97-0054 to F.P.) and F.I.S. (Grant 98/0008-02 to J.V.M.-S.). B.G. is a Fellow of Spanish Ministry of Education (Grant PN95-08930868).Peer Reviewe

Dairy farm management and production practices associated with the presence of Listeria monocytogenes in raw milk and beef

Human listeriosis is a severe foodborne disease caused by Listeria monocytogenes. It is a zoonosis that represents a significant concern for the food industry due to the high mortality rate it causes and the fact that the organism is capable of growing at refrigeration temperatures. Dairy products and ready-to-eat meats are among the foods most often involved in listeriosis outbreaks. Listeria is a common contaminant in the dairy environment, both on the farm and in the processing plant. The main sources of L. monocytogenes in dairy farms are manure and improperly fermented silage. If silage crops are grown on contaminated land, a new cycle of silage contamination and faecal shedding by ruminants that consume such silage may ensue. High loads of L. monocytogenes produced in farm environments may thus represent a primary source for the introduction of this pathogen into the human food supply chain; dairy cows would represent a reservoir for the bacterium, and raw milk and beef would represent the main vehicles for its transmission from dairy farms to humans. Even if contamination originates in post-processing environments, contaminated raw foods may still represent a vehicle for introducing L. monocytogenes into food processing plants. Molecular typing methods have confirmed that common strains of L. monocytogenes are present in dairy farm-associated isolates and isolates from both human epidemic and sporadic cases. Pre-harvest (on-farm) control of listeriosis should be based mainly on the control of manure, silage, herd health and milking practices