Modeling and designing a Listeria monocytogenes control strategy for dry-cured ham taking advantage of water activity and storage temperature

Dry-cured ham is a shelf-stable product that can be contaminated with Listeria monocytogenes due to post-processing operations, compromising the compliance of zero tolerance policies (e.g. US Listeria rule). The present study quantifies the behavior of L. monocytogenes in sliced Spanish dry-cured ham of different water activity (aw) during storage at different temperatures. Inactivation kinetics were estimated by fitting primary models to the experimental data. The effect of temperature and aw on kinetic parameters was characterized through secondary polynomial models. L. monocytogenes viability decreased in all the assayed conditions, confirming that dry-cured ham is not only listeriostatic but listericidal. The fastest and highest reductions were observed at 25 °C, with 1 Log reduction after 6 and 9 days in Iberian and Serrano ham respectively. The work provides scientifically-based data and models to design a low-cost control measure based on a corrective storage as a post-lethality treatment to enhance the accomplishment of zero-tolerance requirements.info:eu-repo/semantics/acceptedVersio

Modelling the piezo-protection effect exerted by lactate on the high pressure resistance of Listeria monocytogenes in cooked ham

Food safety is often based on the application of several preservative (hurdle) factors whose combination must be smartly selected. The aim of the present study was to evaluate the effect of lactate and diacetate on the high pressure processing (HPP) inactivation of three L. monocytogenes strains (CTC1011, CTC1034 and Scott A) in sliced cooked ham. Inoculated vacuum-packed slices of cooked ham formulated without organic acids and with lactate, diacetate or the combination of both were pressurized at 400 MPa for different holding times and the inactivation kinetics were characterised by fitting primary and secondary models. The shape of the inactivation curves for L. monocytogenes depended on both product formulation and strain. Interestingly, lactate caused a dose-dependent piezo-protection in all three strains, as the HPP inactivation rate decreased in cooked ham formulated with increasing amounts of lactate and in comparison with the control product. The design, validation and implementation of HPP requires a tailor-made approach, considering product formulation and selection of strain/s.info:eu-repo/semantics/acceptedVersio

CSF LPV concentrations and viral load in viral suppressed patients on LPV/r monotherapy given once daily

Introduction: Plasma trough concentrations of lopinavir (LPV) given as LPV/r 800/200 mg once daily (OD) are reduced in comparison with 400/100 mg twice daily (BID). While OD dosage of LPV/r is sufficient to achieve viral suppression in plasma, data about drug penetration and viral suppression in central nervous system (CNS) is needed, mainly if LPVr is used as maintenance monotherapy strategy in selected patients. The objective of this study was to evaluate CSF HIV‐1 RNA and CSF LPV concentrations in patients receiving LPV/r monotherapy OD (LPVrMOD). Material and Methods: This is a cross‐sectional sub‐study within a prospective, open‐label pilot simplification study to evaluate the efficacy and safety of LPV/rMOD in virologically suppressed patients previously receiving a BID LPV/r monotherapy regimen (LPV/rMBID), the “Kmon study” (NCT01581853). To assess LPV concentrations and HIV‐1 RNA in CSF, a lumbar puncture (LP) was performed in a subgroup of patients after at least one month of LPVrMOD treatment. Plasma‐paired samples of all patients were also obtained. HIV‐1 RNA was determined by real‐time PCR (limit of detection 40 copies/mL). Liquid chromatography‐tandem mass spectrometry (Tandem labs, NJ) was used to determine CSF and blood plasma LPV concentrations. Results: Nine patients were included. Median (range) age was 48 (34–56) years, median CD4 cell count 672 (252–1,408) cells/mL, median nadir CD4 count 125 (35–537) cells/mL and 40% of subjects were HCV‐positive. Before starting LPV/rMOD median time on a LPV/r‐containing regimen and on LPV/rMBID were 9 (4–11) years and 15 (7–24) months respectively, median time with undetectable HIV viral load was 5 (3–12) years and 2 patients had a previous documented blip. LP was performed a median of 24 (8–36) weeks after starting LPV/rMOD and 24 (11–28) hours after the last LPV/rMOD dose CSF and plasma HIV RNA was 40 copies/mL in all patients. Median LPV CSF concentration was 9.78 (1.93–78.3) ng/mL, median LPV plasma concentration 1,103 (377–16,700) ng/mL and median LPV CSF/plasma ratio 0.3% (0.1–1.2). Conclusions: No CSF viral escape was detected and LPV concentrations were above the IC50 for wtHIV‐1 (1.9 ng/mL). However, as concentrations were close to IC50 in some patients, a careful clinical follow up of patients receiving this regimen would be advisable. Larger longitudinal studies will be helpful for a better understanding of the CNS antiviral activity of LPVr monotherapy

POSTUPAK KOD KOMPLICIRANE PLUĆNE SEKVESTRACIJE U BLIZANAČKOJ TRUDNOĆI

It is well established that fetal pulmonary sequestration complicated by non-immune hydrops fetalis is associated with a high risk of mortality; however, antenatal management remains controversial in these rare cases. The main therapeutic strategies aim to drain the effusions in utero, although there is still debate as to the most adequate drainage route. The two main options are thoracoamniotic shunting and serial thoracocentheses. Others include medical inotropic therapy, alcohol ablation of the vascular pedicle, open fetal surgery and ablation of the feeding vessel with laser surgery. We report the case of a twin pregnancy in which one of the fetuses was affected by an extralobar pulmonary sequestration with large hydrothorax that was successfully treated with serial thoracocentheses.Poznato je da je fetalna plućna sekvestracija komplicirana neimunološkim hidropsom povezana s visokim rizikom mortaliteta; prenatalni postupak je u tim rijetkim slučajevima proturječan. Glavna terapijska strategija je u in utero drenaži izljeva, a još se raspravlja o najprikladnijem načinu drenaže. Dvije su glavne mogućnosti: torako-amnionska prijemosnica i ponovljene serijske torakocenteze. Druge mogućnosti su medikamentozna inotropna terapija, ablacija vaskularne peteljke alkoholom, otvorena fetalna kirurgija i laserska ablacija opskrbne krvne žile. Prikazana je blizanačka trudnoća s ekstralobarnom plućnom sekvestracijom i jakim hidrotoraksom u jednoga fetusa, uspješno liječena serijskom torakocentezom. U 35. tjednu trudnoće je počeo spontani porod, dovršen carskim rezom. Nezahvaćeni fetus je bio težine 1800 grama, a zahvaćeni 2700 grama. Zahvaćeno novorođenče je trebalo ventilatornu potporu, a s 26 dana života učinjen je kirurški zahvat. Nakon jedne godine života oba su novorođenčeta zdrava

Insights into Persistence Mechanisms of a Zoonotic Virus in Bat Colonies Using a Multispecies Metapopulation Model.

Rabies is a worldwide zoonosis resulting from Lyssavirus infection. In Europe, Eptesicus serotinus is the most frequently reported bat species infected with Lyssavirus, and thus considered to be the reservoir of European bat Lyssavirus type 1 (EBLV-1). To date, the role of other bat species in EBLV-1 epidemiology and persistence remains unknown. Here, we built an EBLV-1−transmission model based on local observations of a three-cave and four-bat species (Myotis capaccinii, Myotis myotis, Miniopterus schreibersii, Rhinolophus ferrumequinum) system in the Balearic Islands, for which a 1995-2011 serological dataset indicated the continuous presence of EBLV-1. Eptesicus serotinus was never observed in the system during the 16-year follow-up and therefore was not included in the model. We used the model to explore virus persistence mechanisms and to assess the importance of each bat species in the transmission dynamics. We found that EBLV-1 could not be sustained if transmission between M. schreibersii and other bat species was eliminated, suggesting that this species serves as a regional reservoir. Global sensitivity analysis using Sobol's method revealed that following the rate of autumn−winter infectious contacts, M. schreibersii's incubation- and immune-period durations, but not the infectious period length, were the most relevant factors driving virus persistence

New insights on Listeria monocytogenes growth in pressurised cooked ham: A piezo-stimulation effect enhanced by organic acids during storage

The aim of the present study was to understand growth and survival responses of Listeria monocytogenes during the storage of high pressure processed (HPP) cooked ham formulated with organic acids to inhibit growth of the pathogen. Cooked ham batches were manufactured without organic acids (control), with potassium lactate (2.8% or 4%) or with potassium lactate and sodium diacetate (2.0% + 0.11% or 2.0% + 0.45%). Products were aseptically sliced and inoculated with 107 cfu/g or 102 cfu/g of either L. monocytogenes CTC1034 (a meat isolate) or a cocktail of three isolates (12MOB045Lm, 12MOB089Lm and Scott A). Vacuum-packed samples with 107 cfu/g were HPP at 600 MPa for 3 min, whereas samples with 102 cfu/g were not HPP. Growth or survival of L. monocytogenes was determined during subsequent storage at 8, 12 and 20 °C. Growth or survival was characterized by fitting the experimental data using the primary logistic model and the log-linear with shoulder model, respectively. Secondary models were fitted to characterize the effect of temperature on growth kinetic parameters without or with HPP. For cooked ham without organic acids, growth rates of L. monocytogenes were slightly increased by HPP and lag times were longer. Interestingly, for cooked ham with organic acids, the HPP had a significant stimulating effect on subsequent growth of L. monocytogenes (piezo-stimulation). At 20 °C, the growth rates of L. monocytogenes in cooked ham with lactate were up to 4-fold higher than those of the same product without HPP. The observed enhancement of the piezo-stimulating effect of organic acids on growth rates during storage of HPP cooked ham represents a challenge for the use of organic acids as antimicrobials in these products. A predictive model available as part of the Food Spoilage and Safety Predictor (FSSP) software seemed useful to predict growth and growth boundary of L. monocytogenes in non-pressurised cooked ham. This model was calibrated to take into account the observed piezo-stimulating effect and to predict growth of L. monocytogenes in HPP cooked ham with organic acids.info:eu-repo/semantics/acceptedVersio

New insights on Listeria monocytogenes growth in pressurised cooked ham: A piezo-stimulation effect enhanced by organic acids during storage

The aim of the present study was to understand growth and survival responses of Listeria monocytogenes during the storage of high pressure processed (HPP) cooked ham formulated with organic acids to inhibit growth of the pathogen. Cooked ham batches were manufactured without organic acids (control), with potassium lactate (2.8% or 4%) or with potassium lactate and sodium diacetate (2.0% + 0.11% or 2.0% + 0.45%). Products were aseptically sliced and inoculated with 107 cfu/g or 102 cfu/g of either L. monocytogenes CTC1034 (a meat isolate) or a cocktail of three isolates (12MOB045Lm, 12MOB089Lm and Scott A). Vacuum-packed samples with 107 cfu/g were HPP at 600 MPa for 3 min, whereas samples with 102 cfu/g were not HPP. Growth or survival of L. monocytogenes was determined during subsequent storage at 8, 12 and 20 °C. Growth or survival was characterized by fitting the experimental data using the primary logistic model and the log-linear with shoulder model, respectively. Secondary models were fitted to characterize the effect of temperature on growth kinetic parameters without or with HPP. For cooked ham without organic acids, growth rates of L. monocytogenes were slightly increased by HPP and lag times were longer. Interestingly, for cooked ham with organic acids, the HPP had a significant stimulating effect on subsequent growth of L. monocytogenes (piezo-stimulation). At 20 °C, the growth rates of L. monocytogenes in cooked ham with lactate were up to 4-fold higher than those of the same product without HPP. The observed enhancement of the piezo-stimulating effect of organic acids on growth rates during storage of HPP cooked ham represents a challenge for the use of organic acids as antimicrobials in these products. A predictive model available as part of the Food Spoilage and Safety Predictor (FSSP) software seemed useful to predict growth and growth boundary of L. monocytogenes in non-pressurised cooked ham. This model was calibrated to take into account the observed piezo-stimulating effect and to predict growth of L. monocytogenes in HPP cooked ham with organic acids.info:eu-repo/semantics/acceptedVersio

Evaluation of bacterial biomarkers to aid in challenging inflammatory bowel diseases diagnostics and subtype classification

Supported by the Spanish Ministry of Education and Science, No. SAF2010-15896, No. SAF2013-43284-P and No. SAF2017-82261-P.Peer reviewedPostprintPublisher PD