Prevalence and antimicrobial resistance profile of Salmonella typhi infection in Iraq, 2019-2021.

INTRODUCTION: Salmonella typhi could infect the intestinal tract and the bloodstream or invade body organs and secrete endotoxins. It is endemic in developing countries. It is increasingly evolving antimicrobial resistance to several commonly used antimicrobial agents. MATERIALS AND METHODS: A cross-sectional study was done at Iraqi Communicable Disease Control Center, where all confirmed cases of Salmonella typhi are reported, for a period 2019-2021. All demographic, epidemiological and clinical characteristics of patients, comorbidities, type of samples, distribution of S. typhi by age and gender, time distribution in each year and profile of bacterial resistance and sensitivity to antibiotics were gathered and analysed. RESULTS: Most samples were taken from blood. The mean age of cases during 2019, 2020 and 2021 was 18.7 ± 6.5, 17.7 ± 14.1 and 17.3 ± 12.8. Males constituted 56.7%, 58.5% and 39.8%, respectively. Some cases had comorbidities. Most cases had headache and fever. Some of them had nausea, diarrhoea, vomiting and epigastric pain. The age and sex were significantly associated with years of reporting. The most months of case reporting were June-July (2019 and 2021), Jan. -Feb. (2020). There was an obvious increase in S. typhi resistance to ceftriaxone (92.2%, 86.1%, 88.8%) and ampicillin (77.1%, 76.9%, 81.27%). There was a gradual increase in sensitivity to tetracycline (83.1%, 88.1%, 94%), cotrimoxazole (86.7%, 86.1%, 92.2%), ciprofloxacin (78.3%, 90.1%, 87.8%) and cefixime (77.7%, 72.3%, 72.7%). CONCLUSIONS: There was a sharp rise in resistance rates of the S. typhi in Iraq (during 2019-2021) to ceftriaxone and ampicillin, while there were highest sensitivity rates to imipenem, aztreonam and chloramphenicol. The following recommendations were made: (1) Improvement of general hygiene and food safety measures. (2) Emphasis on vaccination and surveillance of Salmonella infection. (3) Rational use of appropriate antibiotics through implementation of treatment guidelines. (5) Educate communities and travelers about the risks of S. typhi and its preventive measures.

Interactions between risk assessors and risk managers during three major food incidents in Europe.

Risk analysis consists of risk assessment (RA), risk management (RM), and risk communication (RC). In most countries, RA and RM of food safety are separated to achieve a high scientific integrity, and typically occur in sequential order. However, in case of a food safety incident, even though being separate processes, RA and RM are performed simultaneously due to great time pressure and expected high impacts. The aim of this study was to analyze and evaluate the observed interactions between RA and RM processes, during three major food incidents in Europe, and to provide suggestions for possible improvement. Based on the differences observed between the three cases, strengths and weaknesses of each system have been identified. The enterohemorrhagic Escherichia coli (EHEC) crisis in 2011 in Germany, the horsemeat scandal in 2013 in Ireland, and the fipronil incident in 2017 in the Netherlands were used as case studies. Timelines of these incidents and crisis management procedures in place in each of the three countries provided the basis for further analysis. First, results showed that details of the communication processes between RA and RM bodies were frequently lacking in crisis management protocols. Second, RA, RM, and RC processes differed for each incident, due to differences in estimated risk for public health, but also due to differences in the organization within a country. Based on our results, we recommend that crisis management protocols should contain a section on communication between RA, RM, and on communication between member states in the EU.

Effects of incorporating environmental cost and risk aversion on economic values of pig breeding goal traits.

Economic values (EVs) of traits, accounting for environmental impacts and risk preferences of farmers, are required to design breeding goals that contribute to both economic and environmental sustainability. The objective of this study was to assess the effects of incorporating environmental costs and the risk preferences of farmers on the EVs of pig breeding goal traits. A breeding goal consisting of both sow efficiency and production traits was defined for a typical Brazilian farrow-to-finish pig farm with 1,500 productive sows. A mean-variance utility function was employed for deriving the EVs at finishing pig level assuming fixed slaughter weight. The inclusion of risk and risk aversion reduces the economic weights of sow efficiency traits (17%) while increasing the importance of production traits (7%). For a risk-neutral producer, inclusion of environmental cost reduces the economic importance of sow efficiency traits (3%) while increasing the importance of production traits (1%). Genetic changes of breeding goal traits by their genetic standard deviations reduce emissions of greenhouse gases, and excretions of nitrogen and phosphorus per finished pig by up to 6% while increasing farm profit. The estimated EVs could be used to improve selection criteria and thereby contribute to the sustainability of pig production systems.

A stochastic bio-economic pig farm model to assess the impact of innovations on farm performance.

Recently developed innovations may improve the economic and environmental sustainability of pig production systems. Generic models are needed to assess the impact of innovations on farm performance. Here we developed a stochastic bio-economic farm model for a typical farrow-to-finish pig farm to assess the impact of innovations on private and social profits. The model accounts for emissions of greenhouse gases from feed production and manure by using the shadow price of CO2, and for stochasticity of economic and biological parameters. The model was applied to assess the impact of using locally produced alternative feed sources (i.e. co-products) in the diets of finishing pigs on private and social profits of a typical Brazilian farrow-to-finish pig farm. Three cases were defined: a reference case (with a standard corn-soybean meal-based finishing diet), a macaúba case (with a macaúba kernel cake-based finishing diet) and a co-products case (with a co-products-based finishing diet). Pigs were assumed to be fed to equal net energy intakes in the three cases. Social profits are 34% to 38% lower than private profits in the three cases. Private and social profits are about 11% and 14% higher for the macaúba case than the reference case, whereas they are 3% and 7% lower for the co-products case, respectively. Environmental costs are higher under the alternative cases than the reference case suggesting that other benefits (e.g. costs and land use) should be considered to utilize co-products. The CV of farm profits is between 75% and 87% in the three cases following from the volatility of prices over time and variations in biological parameters between fattening pigs.

Correlation between erectile function and cardiovascular risk factors by assessing arterial stiffness and myocardial perfusion imaging and carotid artery intima-media thickness.

AIM: Aim of the study was to analyze the relationship between erectile function and cardiovascular risk factors by assessing arterial stiffness and myocardial scintigraphy and carotid artery intima-media thickness. METHODS: Fifty-nine consecutive asymptomatic men aged 30-86 years, were included. Myocardial scintigraphy, Doppler sonography of carotid artery and arterial stifness parameters were performed. Erectile function was evaluated with a validated erectile function index quesionnaire. RESULTS: The control group included 18 subjects and the study group included 41 subjects with abnormal IIEF-5 scores. We compared both group's IIEF-5 scores there was significant correlation between IIEF-5 and cholesterol (P<0.05) and HbA1c (P<0.05). Moreover, there was a significant correlation in patients with abnormal IIEF-5 scores and pathologic myocardial perfusion imaging (P<0.05) and triglyceride (P<0.05). A two-factor ANOVA showed two significant interactions patients with abnormal cholesterol and abnormal pulse wave velocity, augmentation index had lower IIEF-5 scores; patients with abnormal triglyceride values, and abnormal Hb1Ac had lower IIEF-5 scores. CONCLUSION: Eretile dysfunction (ED) prevalence is high in cardiologic patients referred for myocardial nuclear imaging. There is a significant relation between ED, diabetes and hyperlipidemia, and advanced age. Myocardial nuclear scan and arterial stiffness parameters could be used to stratify the cardiovascular risk factors in ED patients.

Tipping off endothelial tubes: nitric oxide drives tip cells.

Angiogenesis, the formation of new blood vessels from pre-existing vessels, is a complex process that warrants cell migration, proliferation, tip cell formation, ring formation, and finally tube formation. Angiogenesis is initiated by a single leader endothelial cell called "tip cell," followed by vessel elongation by "stalk cells." Tip cells are characterized by their long filopodial extensions and expression of vascular endothelial growth factor receptor-2 and endocan. Although nitric oxide (NO) is an important modulator of angiogenesis, its role in angiogenic sprouting and specifically in tip cell formation is poorly understood. The present study tested the role of endothelial nitric oxide synthase (eNOS)/NO/cyclic GMP (cGMP) signaling in tip cell formation. In primary endothelial cell culture, about 40% of the tip cells showed characteristic sub-cellular localization of eNOS toward the anterior progressive end of the tip cells, and eNOS became phosphorylated at serine 1177. Loss of eNOS suppressed tip cell formation. Live cell NO imaging demonstrated approximately 35% more NO in tip cells compared with stalk cells. Tip cells showed increased level of cGMP relative to stalk cells. Further, the dissection of NO downstream signaling using pharmacological inhibitors and inducers indicates that NO uses the sGC/cGMP pathway in tip cells to lead angiogenesis. Taken together, the present study confirms that eNOS/NO/cGMP signaling defines the direction of tip cell migration and thereby initiates new blood vessel formation.

Molecular modeling and simulation of the human eNOS reductase domain, an enzyme involved in the release of vascular nitric oxide.

Homology modeling of the reductase domain of endothelial nitric oxide synthase (eNOS), which regulates the catalytic activity of eNOS, and molecular dynamics studies focusing especially on the serine residues S615, S633, and S1177 were performed. MD analysis of this structure revealed that S633 is highly flexible and accessible to solvent molecules, while S1177 becomes highly flexible when S633 is phosphorylated. The presence of intramolecular interactions between S1177 among the major serine residues underscores its structural importance to the efficient synthesis of nitric oxide in endothelium. In order to evaluate the appropriateness of phosphomimetic (for phosphorylation) and phosphomutant (for dephosphorylation) eNOSs for use as experimental model systems, the structural dynamics and conformational changes in phosphomimetic (S615D, S633D, S1177D) and phosphomutant (S615A, S633A, S1177A) eNOSs were investigated. Phosphomimetic and phosphomutant eNOSs portrayed S633 as a modulator of S1177, whereas such correlations could not be observed in native and phosphorylated eNOSs. Computational analysis of the docked complex revealed that phosphorylated pS1177 and pS615 have high affinity for Akt (one of the key kinases in the eNOS activation pathway), with a significant number of hydrogen bonds and salt bridges observed between these residues and Akt . This work therefore provides evidence of the subtle structural changes that occur within the reductase domain which contribute to the stability-flexibility-activity relationship of eNOS. Such subtle changes are of great importance in the context of regulated nitric oxide release by different phosphorylated forms of eNOS and the need to account for the existence of subtle differences between real proteins and experimental model systems.

Analysing calcium dependent and independent regulation of eNOS in endothelium triggered by extracellular signalling events.

The vascular endothelium, the intima of blood vessels, coordinately interacts with several biochemical factors expressing endothelial nitric oxide synthase (eNOS) to produce nitric oxide (NO), a potent endogenous vasodilator. The present study investigated the regulation of eNOS by multiple molecular signal transduction pathways, namely vascular endothelial growth factor (VEGF-A) and shear stress which are implicated in the process of angiogenesis and vascular remodelling respectively. In response to signal transduction upstream by VEGF-A and shear stress, different signalling pathways mediated by kinases and intracellular calcium potentiates eNOS activation leading to nitric oxide release. Our study revealed a distinct pattern of eNOS activation driven by VEGF-A and shear stress, maintaining the signalling specificity of the respective pathways. A transient response to eNOS activation was observed under VEGF-A and shear stress stimulus when mediated by calcium dependent cascades, whereas a sustained response was produced by calcium independent vascular signalling kinases. Furthermore, we found that the basal arterial shear stress enhanced eNOS activity when stimulated synergistically even at low VEGF-A levels which might be utilized to facilitate specific endothelial cell functions. Moreover, our study revealed that the presence of PI3K imparted transient behaviour to PLCγ1 supporting the hypothesis that regression and formation of tube structures are mediated by PLCγ1 and PI3K respectively in endothelial cells. This fact is corroborated by the absence of transient behaviour when PI3K is inhibited. We therefore obtained subtle insights into the control mechanism governing the role of specific signalling proteins which are obligate for the regulation of endothelial cell function and the consequent modulation of the nitric oxide release pattern.

Nitric oxide protects endothelium from cadmium mediated leakiness.

Cadmium targets the vascular endothelium causing endothelial dysfunction and leakiness of endothelial barrier. Nitric oxide plays a major role in mediating endothelial functions including angiogenesis, migration and permeability. The present study investigates the nitric oxide effects on cadmium induced endothelial leakiness. Results of ex vivo and in vitro permeability assays showed that even a sub-lethal dose of cadmium chloride (1 µM) was sufficient to induce leakiness of endothelial cells. Cadmium drastically altered the actin polymerisation pattern and membrane tension of these cells compared to controls. Addition of nitric oxide donor Spermine NONOate (SP) significantly blunted cadmium-mediated effects and recover endothelial cells integrity. Cadmium-induced cytoskeletal rearrangements and membrane leakiness are associated with the low nitric oxide availability and high reactive oxygen species generation. In brief, we show the protective role of nitric oxide against cadmium-mediated endothelial leakiness.

Rapid and sensitive detection of major uropathogens in a single-pot multiplex PCR assay.

Urinary tract infection (UTI) is among the most common bacterial infections and poses a significant healthcare burden. Escherichia coli is the most common cause of UTI accounting for up to 70 % and a variable contribution from Proteus mirabilis, Pseudomonas aeruginosa and Klebsiella pneumoniae. To establish a complete diagnostic system, we have developed a single-tube multiplex PCR assay (mPCR) for the detection of the above-mentioned four major uropathogens. The sensitivity of the assay was found to be as low as 10(2) cfu/ml of cells. The mPCR evaluated on 280 clinical isolates detected 100 % of E. coli, P. aeruginosa, P. mirabilis and 95 % of K. pneumonia. The assay was performed on 50 urine samples and found to be specific and sensitive for clinical diagnosis. In addition, the mPCR was also validated on spiked urine samples using 40 clinical isolates to demonstrate its application under different strain used in this assay. In total, mPCR reported here is a rapid and simple screening tool that can compete with conventional biochemical-based screening assays that may require 2-3 days for detection.

Nitric oxide/cGMP protects endothelial cells from hypoxia-mediated leakiness.

Leakiness of the endothelial bed is attributed to the over-perfusion of the pulmonary bed, which leads to high altitude pulmonary edema (HAPE). Inhalation of nitric oxide has been successfully employed to treat HAPE patients. We hypothesize that nitric oxide intervenes in the permeability of the pulmonary macrovascular endothelial bed to rectify the leaky bed under hypoxia. Our present work explores the underlying mechanism of 'hypoxia-mediated' endothelial malfunction by using human umbilical cord-derived immortalized endothelial cells, ECV-304, and bovine pulmonary artery primary endothelial cells. The leakiness of the endothelial monolayer was increased by two-fold under hypoxia in comparison to cells under normoxia, while optical tweezers-based tethering assays reported a higher membrane tension of endothelial cells under hypoxia. Phalloidin staining demonstrated depolymerization of F-actin stress fibers and highly polarized F-actin patterns in endothelial cells under hypoxia. Nitric oxide, 8-Br-cGMP and sildenafil citrate (phosphodiesterase type 5 inhibitor) led to recovery from hypoxia-induced leakiness of the endothelial monolayers. Results of the present study also suggest that 'hypoxia-induced' cytoskeletal rearrangements and membrane leakiness are associated with the low nitric oxide availability under hypoxia. We conclude that nitric oxide-based recovery of hypoxia-induced leakiness of endothelial cells is a cyclic guanosine monophosphate (cGMP)-dependent phenomenon.

Single particle tracking of correlated bacterial dynamics.

Pattern formation in 3D random media has been a topic of interest in soft matter and biological systems. However, the onset of long-range microscopic ordering has not been explored in randomly moving self-propelled particles due to a lack of model systems as well as local probe techniques. In this article, we report on a novel experiment, using motile Escherichia coli bacteria as a model system, to study the onset of dynamic correlation and collective movement in three-dimension. We use fluctuation of an optically trapped micron-size bead as a detector of correlated bacterial motion, and further study this behavior by analyzing the motility of fluorescent bacteria in a confocal volume. We find evidence of dynamic correlation at very low volume fractions (0.01). We show that the magnitude of this correlation strongly depends on the interbacterial distances and their coupling modes. This opens up possibilities to probe long-range pattern formation in actively propelled cells or organisms coupled through hydrodynamics and/or chemical signaling.

Compaction of single DNA molecules induced by binding of integration host factor (IHF).

We studied the interaction between the integration host factor (IHF), a major nucleoid-associated protein in bacteria, and single DNA molecules. Force-extension measurements of lambda DNA and an analysis of the Brownian motion of small beads tethered to a surface by single short DNA molecules, in equilibrium with an IHF solution, indicate that: (i) the DNA-IHF complex retains a random, although more compact, coiled configuration for zero or small values of the tension, (ii) IHF induces DNA compaction by binding to multiple DNA sites with low specificity, and (iii) with increasing tension on the DNA, the elastic properties of bare DNA are recovered. This behavior is consistent with the predictions of a statistical mechanical model describing how proteins bending DNA are driven off by an applied tension on the DNA molecule. Estimates of the amount of bound IHF in DNA-IHF complexes obtained from the model agree very well with independent measurements of this quantity obtained from the analysis of DNA-IHF crosslinking. Our findings support the long-held view that IHF and other histone-like proteins play an important role in shaping the long-scale structure of the bacterial nucleoid.

Objective-type dark-field illumination for scattering from microbeads.

We introduce a method for detecting and tracking small particles in a solution near a surface. The method is based on blocking the backreflected illumination beam in an objective-type total internal reflection microscope, leaving unhindered the light scattered by the particles and resulting in dark-field illumination. Using this method, we tracked the motion of 60-nm polystyrene beads with a signal-to-noise ratio of 6 and detected 20-nm gold particles with a signal-to-noise ratio of 5. We illustrate the method's use by following the Brownian motion of small beads attached by short DNA tethers to a substrate.

[Pulmonary tuberculosis secondary to fistulization of Pott's abscess. A case report]. / Tuberculose pulmonaire secondaire à la fistulisation d'un abcès pottique. Rapport d'un cas.

The authors report a case of pulmonary tuberculosis appearing after an endobronchial fistula from a Pott's abscess. Such a clinical presentation is rare even in a developing country (PVD), where there is experience of more than 200 cases of tuberculous spondylodiscitis seen over a period of six years. The frequency of paravertebral abscess during the course of Pott's disease is around 52%, in the thoracic lesion their exteriorization by endobronchial fistula is around 4% (5 out of 114). The outcome is generally more simple and here a cure was achieved after six months of chemotherapy.