Genotyping of Listeria monocytogenes isolates by high-resolution melting curve (HRM) analysis of tandem repeat locus.

Listeria monocytogenes is responsible for causing listeriosis, a type of food poisoning with high mortality. This bacterium is mainly transmitted to humans through the consumption of contaminated foods. Detection of L. monocytogenes through molecular methods is crucial for food safety and clinical diagnosis. Present techniques are characterized by low discrimination power and high cost, as well as being time-consuming and taking several days to give the final result. In our study, MLVA-HRM (Multiple-Locus Variable-number tandem repeats Analysis ‒ High-Resolution Melting) was investigated as an alternative method for a fast and precise method for the genotyping of L. monocytogenes isolates. Forty-eight isolates of L. monocytogenes obtained from the microbial bank of Department of Microbiology, Iran University of Medical Sciences, were typed by MLVA-HRM analysis using five Variable Numbers of Tandem Repeat (VNTR) loci. A total of 43 different types were obtained. This research demonstrated the usefulness of the MLVA-HRMA method and its ability to discriminate L. monocytogenes isolates. Since this method is easier and more efficient than existing methods, it can be widely used in food processing plants and diagnostic laboratories as a fast and accurate method.

Genotyping of Listeria monocytogenes isolates by high-resolution melting curve (HRM) analysis of tandem repeat locus

Abstract Listeria monocytogenes is responsible for causing listeriosis, a type of food poisoning with high mortality. This bacterium is mainly transmitted to humans through the consumption of contaminated foods. Detection of L. monocytogenes through molecular methods is crucial for food safety and clinical diagnosis. Present techniques are characterized by low discrimination power and high cost, as well as being time-consuming and taking several days to give the final result. In our study, MLVA-HRM (Multiple-Locus Variable-number tandem repeats Analysis ‒ High-Resolution Melting) was investigated as an alternative method for a fast and precise method for the genotyping of L. monocytogenes isolates. Forty-eight isolates of L. monocytogenes obtained from the microbial bank of Department of Microbiology, Iran University of Medical Sciences, were typed by MLVA-HRM analysis using five Variable Numbers of Tandem Repeat (VNTR) loci. A total of 43 different types were obtained. This research demonstrated the usefulness of the MLVA-HRMA method and its ability to discriminate L. monocytogenes isolates. Since this method is easier and more efficient than existing methods, it can be widely used in food processing plants and diagnostic laboratories as a fast and accurate method.

The Value of Physiological Scoring Criteria in Predicting the In-Hospital Mortality of Acute Patients; a Systematic Review and Meta-Analysis.

INTRODUCTION: There is no comprehensive meta-analysis on the value of physiological scoring systems in predicting the mortality of critically ill patients. Therefore, the present study intended to conduct a systematic review and meta-analysis to collect the available clinical evidence on the value of physiological scoring systems in predicting the in-hospital mortality of acute patients. METHOD: An extensive search was performed on Medline, Embase, Scopus, and Web of Science databases until the end of year 2020. Physiological models included Rapid Acute Physiology Score (RAPS), Rapid Emergency Medicine Score (REMS), modified REMS (mREMS), and Worthing Physiological Score (WPS). Finally, the data were summarized and the findings were presented as summary receiver operating characteristics (SROC), sensitivity, specificity and diagnostic odds ratio (DOR). RESULTS: Data from 25 articles were included. The overall analysis showed that the area under the SROC curve of REMS, RAPS, mREMS, and WPS criteria were 0.83 (95% CI: 0.79-0.86), 0.89 (95% CI: 0.86-0.92), 0.64 (95% CI: 0.60-0.68) and 0.86 (95% CI: 0.83-0.89), respectively. DOR for REMS, RAPS, mREMS and WPS models were 11 (95% CI: 8-16), 13 (95% CI: 4-41), 2 (95% CI: 2-4) and 17 (95% CI: 5-59) respectively. When analyses were limited to trauma patients, the DOR of the REMS and RAPS models were 112 and 431, respectively. Due to the lack of sufficient studies, it was not possible to limit the analyses for mREMS and WPS. CONCLUSION: The findings of the present study showed that three models of RAPS, REMS and WPS have a high predictive value for in-hospital mortality. In addition, the value of these models in trauma patients is much higher than other patient settings.

Risk Factors for Road Traffic Injury-Related Mortality in Iran; a Systematic Review and Meta-Analysis.

INTRODUCTION: Gathering information regarding the risk factors of mortality and disability due to road traffic injuries can provide evidence for adopting effective interventions to reduce the burden of the injury. Therefore, the present study intends to identify the most important risk factors of road accident-related mortality in Iran by conducting a systematic review and meta-analysis. METHODS: Search was done in English and Persian electronic databases, for articles published until the end of 2020. Cross-sectional, cohort and case-control studies were included. Risk factors were divided into age and sex, road related factors, exceeding speed limit, road user behaviors, vehicle related factors, weather condition, and light condition. Data were reported as adjusted odds ratio (OR) of death with 95% confidence interval (95% CI). RESULTS: 20 studies were included (2,682,434 traffic accident victims and 23,272 deaths; mortality rate=1.28%). The risk of death in road traffic injuries in men was 1.66 times higher than women (OR = 1.66; 95% CI: 1.03, 2.68) and with each year increase in age, the risk increased by 1% (OR = 0.01; 95% CI: 1.00, 1.01). In addition, accident in urban streets (OR = 1.76; 95% CI: 1.08, 2.88), roadway defects (OR = 2.15, 95% CI: 1.59, 2.91), and not driving on a flat and straight road (OR = 1.60; 95% CI: 1.14, 2.24) were the most important road-related risk factors for mortality. Exceeding the speed limit was another risk factor of death (OR = 3.16; 95% CI: 2.83, 3.54). However, regarding exceeding safe speed, only three studies have been included, which greatly reduces the power of analysis. Not maintaining focus on the road (OR = 2.99; 95% CI: 1.49, 6.04), not fastening seatbelt (OR = 3.11; 95% CI: 1.08, 8.91), and reckless overtaking (OR = 4.04; 95% CI: 3.34, 4.89) were independent road user-related risk factors for mortality. Risk of pedestrian mortality in comparison with drivers and passengers is 2.07 times higher (OR = 2.07; 95% CI: 1.53, 2.58). In addition, risk of death in accidents occurring during daylight hours (OR = 0.26; 95% CI: 0.18, 0.37) is lower than that of other hours. No significant relationship was present between mortality and vehicle types (four-wheeled vehicle: OR = 0.99; 95% CI: 0.050, 1.97; two-wheeled vehicle: OR = 0.75; 95% CI: 0.48, 1.16). In the case of vehicle-related factors, only 2 studies were included, which also dealt only with the type of vehicle (two-wheeled/four-wheeled). Vehicle-related factors such as the car model, its safety rating, and safety standards were not mentioned in any study. CONCLUSION: Low to very low-level evidence shows that there is a significant relationship between factors related to age, sex, road, road user, exceeding the speed limit, and light condition with the mortality of traffic accident victims. However, all studies included in the present study were retrospectively designed and the analyses were not adjusted for most of the key potential confounders. Therefore, it seems that despite years of effort by researchers in the field of traffic accidents in Iran, there is still no comprehensive and reliable picture of the most important risk factors for road accident mortalities in Iran.

Spatial analysis of Toxocara spp. eggs in soil as a potential for serious human infection.

Toxocara spp. cause one of the most widespread soil-transmitted helminthic infections worldwide. In both developed and developing countries, soil contamination with Toxocara eggs is considered as a major threat to public health. A total of 515 soil samples from 89 sampling sites were collected from different locations of public health such as Wastelands and Streets, public parks, and marginal areas. The soil samples were examined for Toxocara eggs using a centrifugal-floatation technique utilizing a saturated sodium nitrate solution. centralization of positive soil samples in the province was studied by Spatial Statistics Techniques such as Average Nearest Neighbors and Spatial Autocorrelation and Kernel Density Function Toxocara spp. eggs were found in 94 (18.25 %) out of 515 samples collected from the studied areas. According to the results obtained, marginal areas are often contaminated with eggs of Toxocara. Consequently, preventive measures including health education should be implemented to reduce the potential risk of this parasitic infection.

Evaluation of gene expression and protein structural modeling involved in persister cell formation in Salmonella Typhimurium.

Persisters are phenotypic variants of the bacterial population that survive against lethal doses of bactericidal antibiotics.These phenotypes are created in numerous bacterial species, including those of clinical significance, such as Salmonella Typhimurium. Since persister cells are associated with the failure of antibiotic treatment and infection recurrence, it is crucial to identify the mechanisms that influence the formation of these cells. The aim of this study is to investigate the persister cell formation and expression analysis as well as to predict the 3D structure of the genes involved in the production of persister cells. The presence of persisters in S. Typhimurium was determined by time dependent killing of different types of bactericidal antibiotics and expression of genes associated with persister cell formation which was assessed five hours after the addition of antibiotics by the qRT-PCR. Indeed, the 3D structural model of the proteins studied was predicted by performing several computational methods of retrieved primary protein sequences. The results of the study showed that the S. Typhimurium produced high levels of persister cells in the exposure of bactericidal antibiotics. Furthermore, qRT-PCR resulted in the fact that the expression of related genes was different depending on the type of antibiotic. Overall, this study provides information on the creation of persister cells and the role of different genes in the formation of these cells and structure of proteins involved in the production of persister cells in S. Typhimurium.

Potential prognostic roles of serum lactate and Creatine kinase levels in poisoned patients.

BACKGROUND: Examination of serum lactate level and its changes, as an indicator of tissue oxygenation, as well as level of creatine kinase (CK) inhibitors, as a factor of mortality which partially expresses heart, brain, and muscle damage, may be considered as tools to determine prognosis in critically ill patients. We aimed to evaluate these two factors as potential prognostic factors in critically poisoned patients admitted to our toxicology ICU. METHOD: This is a cross-sectional descriptive-analytic study that was performed on poisoned patients referred to emergency department of Loghman Hakim Hospital. One-hundred critically poisoned patients who had been admitted to ICU were conveniently chosen using a random number table and included into the study after obtaining consent forms from their next of kin. Their serum lactate and CK levels were checked on admission. These levels were compared subsequently between survivors and non-survivors to seek for their potential prognostic role. RESULTS: In a total of 100 patients enrolled, 61 were male. Serum level of lactate (with a cut off of 26 mg/dL) and serum CK with a cutoff point of 169 U/L could have prognosticated death with sensitivity and specificity of 78 and 77% (for lactate) and 74 and 62% (for serum CK), respectively. CONCLUSIONS: In poisoned patients, serum lactate and CK can be used as possible prognostic factors because they rapidly increase in the serum and are easily detectable.

The expression of type II TA system genes following exposure to the sub-inhibitory concentration of gentamicin and acid stress in Brucella spp.

BACKGROUND: Brucellosis is one of the most common diseases that afflicts both humans and animals. Bacteria react to stress conditions using different mechanisms one of which is Toxin-Antitoxin (TA) systems. It is believed that the Toxin-Antitoxin (TA) systems have a key role in the chronicity of the disease. This study investigated the expression of TA system genes under acid and antibiotic stresses in Brucella spp. METHODS: Fifty Brucella isolates (17 isolated from animals and 31 isolated from human specimens, and two standard strains) were analyzed using PCR (using two pairs of primers). Then, to determine the effects of sub-MIC of gentamicin on bacterial survival and growth, colony forming unit was quantitated and turbidity was assessed following the treatment of Brucella spp, with ½ MIC of gentamicin at different time intervals. Furthermore, the colony forming unit of Brucella spp, was assessed under acid stress (pH = 5.5) compared to the control (pH = 7.6). Moreover, the expression of TA system genes in Brucella spp, was evaluated 1 h after treatment using qRT-PCR method. RESULTS: A total of 50 isolates, including 41 (82%) Brucella melitensis and 7 (14%) Brucella abortus with two standard strains Brucella melitensis (16 M) and Brucella abortus (B19) were investigated. Our results revealed the reduced growth of Brucella spp. in the presence of sub-MIC of gentamicin compared to the control. Furthermore, according to the results of qRT-PCR assay, gentamicin could increase the expression of TA system genes. Also, results of qRT-PCR showed that under acid stress, the expression of TA system gene COGT/COGAT decreased compared to the control. CONCLUSION: Although the exact role of the TA systems in response to stress is still unclear, our study provided information on the effect of the type II TA systems under the acid and antibiotic stress conditions. However, further studies are still required.

Persister cells formation and expression of type II Toxin-Antitoxin system genes in Brucella melitensis (16M) and Brucella abortus (B19).

BACKGROUND & OBJECTIVE: Persister cells are defined as a subpopulation of bacteria that are capable of reducing their metabolism and switching to dormancy in stress conditions. Persister cells formation has been attributed to numerous mechanisms, including stringent response and Toxin-Antitoxin (TA) systems. This study aimed to investigate the hypothetical role of TA systems in persister cells formation of Brucella strains by evaluating toxins of type II TA systems (RelE, Fic, Brn T, cogT) expression. METHODS: Brucella strains treated with a lethal dose of gentamicin and ampicillin and to determine the number of surviving cells, bacterial colonies were counted at different time intervals. The role of TA systems in persister cell formation was then determined by toxin expression levels using qRT- PCR method. RESULTS: Our results showed the viability of persister cells after 7 h. The results of relative qRT- PCR showed higher levels of toxin gene expression due to stress conditions, suggesting the possible role of TA systems in persister cells formation and antibiotics tolerance. CONCLUSION: The results of this study showed that considering the importance of persistence and the tolerance to antibiotics, further studies on persister cells formation and related genes such as the TA system genes in Brucella strains might help us to identify the precise mechanisms leading to persister cells formation.

Effects of sub-inhibitory concentrations of antibiotics and oxidative stress on the expression of type II toxin-antitoxin system genes in Klebsiella pneumoniae.

OBJECTIVES: Sub-inhibitory concentrations (sub-MICs) of antibiotics reflect the conditions that bacteria encounter in tissues and the natural environment. Sub-MICs of antibiotics can induce stress and alter the expression of different bacterial genes. Bacteria react to stress conditions using different mechanisms, one of which is the toxin-antitoxin (TA) system. This study investigated the expression of the TA system genes under oxidative and antibiotic stresses in Klebsiella pneumoniae (K. pneumoniae). METHODS: To determine the effects of sub-MICs of gentamicin, nalidixic acid, ceftazidime, and certain concentrations of H2O2 on bacterial survival and growth, colony forming units were quantitated and turbidity was assessed following the treatment of K. pneumoniae with ½ MICs of antibiotics and 5 mM H2O2 at different time intervals. The expression of TA system genes in K. pneumoniae was evaluated 1 h after treatment using the quantitative real-time PCR (qRT-PCR) method. RESULTS: The results revealed reduced K. pneumoniae growth in the presence of sub-MICs of antibiotics and 5 mM H2O2 compared to the control. Furthermore, according to the results of the qRT-PCR assay, only the presence of gentamicin could increase the expression of TA system genes. CONCLUSION: Although the exact role of the TA systems in response to stress is still unclear, this study provided information on the effect of the type II TA systems under oxidative and antibiotic stress conditions.

Management recommendations for body stuffers at emergency units.

Managing body packers and stuffers is a challenge to emergency physicians, stuffers in particular, as there is no systematic approach to their treatment. The aim of this study was therefore to review all available literature on body stuffing and propose a guide to manage these patients. We searched Medline/PubMed, Google Scholar, and Scopus for published work on body stuffers using key words "body stuffer", "body stuffing", "poisoning", "toxicity", and "treatment" without a time limit and retrieved 290 articles, of which 61 remained after exclusion of those on "body packers" and repetitive documents. This review article evaluates and summarises the information gathered from them. The main step in body stuffer management is observation to make sure that they have passed all the swallowed packages of drugs of abuse. In some cases, imaging can be quite useful. Diagnostic pitfalls may be avoided with abdominopelvic CT without contrast, which is probably the best diagnostic method to determine the presence and the number of packages in these patients. Treatment should be specific for each group of drugs, whether it is opioids, cocaine, or amphetamine. Surgical interventions are indicated for obstruction of the intestines or package rupture. Legal precautions should be taken because of the legal complexity of body stuffing cases.