Congenital sucrase-isomaltase deficiency in Türkiye; a single center experience.

BACKGROUND: Congenital sucrase-isomaltase deficiency (CSID) is a rare inherited carbohydrate malabsorption disorder caused by sucrase-isomaltase (SI) gene variants. In CSID, an autosomal recessively inherited disease, symptoms can also be seen in individuals with heterozygous mutations. METHODS: The variant spectrum was evaluated retrospectively in individuals who presented with chronic diarrhea between 2014 and 2022 and had undergone genetic testing of the SI gene considering CSID due to diet-related complaints. RESULTS: Ten patients with chronic diarrhea were genetically evaluated with SI gene sequencing. In patients diagnosed with CSID and whose symptoms improved with enzyme replacement therapy, the genetic mutation zygosity was found to be heterozygous at a rate of 90%. In 10% of the patients, the mutation was homozygous. Limiting consuming sucrose and isomaltose foods reduced the patients' complaints, but the symptoms did not disappear completely. With the initiation of sacrosidase enzyme replacement therapy, the patient's complaints completely disappeared. CONCLUSION: In CSID, defined as an autosomal recessive disease, clinical symptoms can also be seen in heterozygous cases previously described as carriers, and these patients also benefit from sacrosidase enzyme replacement therapy. In light of these findings, the autosomal recessive definition of CSID does not fully characterize the disease.What is Known:CSID is a rare inherited carbohydrate malabsorption disorder caused by sucrase-isomaltase gene variants.In congenital sucrase-isomaltase deficiency, an autosomal recessively inherited disorder, symptoms can also be seen in individuals with heterozygous mutations.What is new:Severe disease symptoms can also be seen in heterozygous cases, which were thought to be carriers because the disease was previously described as autosomal recessive.Sacrosidase enzyme replacement therapy also eliminates the disease symptoms in patients with heterozygous CSID mutations.This is the second study on sucrase-isomaltase enzyme deficiency pediatric groups in Türkiye and Europe.

This is the study to evaluate the congenital sucrase-isomaltase enzyme deficiency in chronic diarrhea cases covering adults and childhood in our country and the clinical features and treatment response characteristics of the variants detected in these patients.In addition, another aim of our study is that sucrase­isomaltase enzyme deficiency should be considered in the differential diagnosis and should be kept in mind, especially in cases with chronic diarrhea whose cause cannot be determined in childhood.

An Extraordinary Case of Autoimmune Polyendocrinopathy-Candidiasis-Ectodermal Dystrophy (APECED) Syndrome Misdiagnosed as Juvenile Idiopathic Arthritis on Admission.

Background: APECED is a syndrome characterized by autoimmune polyendocrinopathy, candidiasis, and ectodermal dystrophy. The most observed clinical findings are chronic mucocutaneous candidiasis, hypoparathyroidism, and autoimmune adrenal insufficiency. Case Presentation. A three-year-old male patient was admitted with classical signs of juvenile idiopathic arthritis and treated with nonsteroidal anti-inflammatory drugs. During follow-up, signs of autoimmunity, candidiasis, nail dystrophy, and onychomycosis were observed. The parents were consanguineous, and targeted next-generation sequencing was performed. A homozygous mutation in the AIRE gene SAND domain (c.769C > T, p.Arg257Ter) was detected, and the patient was diagnosed with APECED syndrome. Conclusion: Inflammatory arthritis is rarely described in association with APECED and is often misdiagnosed as juvenile idiopathic arthritis. In APECED cases, nonclassical symptoms such as arthritis may occur before developing classical symptoms and considering the diagnosis of APECED in patients with CMC and arthritis is useful for early diagnosis before development of complications and management of disease.

SARS-CoV-2 Antibodies in Children with Chronic Disease from a Pediatric Gastroenterology Outpatient Clinic.

Purpose: At the beginning of the Coronavirus disease (COVID-19) epidemic, physicians paid close attention to children with chronic diseases to prevent transmission or a severe course of infection. We aimed to measure the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody levels in children with chronic gastrointestinal and liver diseases to analyze the risk factors for infection and its interaction with their primary disease. Methods: This cross-sectional study analyzed SARS-CoV-2 antibody levels in patients with gastrointestinal and liver diseases (n=141) and in healthy children (n=48) between January and February 2021. Results: During the pandemic, 10 patients (7%) and 1 child (2%) had confirmed COVID-19 infection (p=0.2). The SARS-CoV-2 antibody test was positive in 36 patients (25.5%) and 11 children (22.9%) (p=0.7). SARS-CoV-2 antibody positivity was found in 20.4%, 26.6%, 33.3%, and 33.3% of patients with chronic liver diseases, chronic gastrointestinal tract diseases, cystic fibrosis, and liver transplantation recipients, respectively (p>0.05, patients vs. healthy children). Risk factors for SARS-CoV-2 antibody positivity were COVID-19-related symptoms (47.2% vs. 14.2%, p=0.00004) and close contact with SARS-CoV-2 polymerase chain reaction-positive patients (69.4% vs. 9%, p<0.00001). The use, number, and type of immunosuppressants and primary diagnosis were not associated with SARS-CoV-2 antibody positivity. The frequency of disease activation/flare was not significant in patients with (8.3%) or without (14.2%) antibody positivity (p=0.35). Conclusion: SARS-CoV-2 antibodies in children with chronic gastrointestinal and liver diseases are similar to that in healthy children. Close follow-up is important to understand the long-term effects of past COVID-19 infection in these children.

When Should Endoscopic Interventions Be Performed in Children with Severe Anemia?

OBJECTIVE: Anemia is a common problem in outpatient clinics, and endoscopic interventions are one of the initial steps to rule out the gastrointestinal causes. In this study, we aimed to analyze the diagnostic yield of endoscopic interventions in children with severe anemia. MATERIALS AND METHODS: The demographic features, laboratory findings, and endoscopic and histopathological findings of 65 children with severe anemia (hemoglobin <7 g/dL) (mean age of 12.1 ± 4.4 years, 73.8% female) who underwent endoscopic interventions were recorded from the files. Patients were divided into 2 groups according to the presence of positive endoscopic findings and/or histopathological examination. Factors that may predict the presence of positive endoscopic findings and/or histopathological examination were analyzed. RESULTS: After a colonoscopy and/or upper gastrointestinal endoscopy, the etiology of anemia was identified in 35 patients, and the major diagnosis of Helicobacter pylori gastritis in 16.9% and gastrointestinal ulcer in 10.8% of the patients was made. No gastrointestinal pathology was detected in 30 patients. The diagnostic yield of endoscopic examination in patients with severe anemia was 53.8% (95% CI: 63.3-67.7). Presence of hypoalbuminemia (P = .021), high erythrocyte sedimentation rate (P = .006), and high C-reactive protein (P = .03) was significantly associated with positive findings in endoscopic interventions. CONCLUSION: We recommend performing upper gastrointestinal endoscopy and/or colonoscopy in patients with severe anemia associated with gastrointestinal symptoms and using laboratory findings of hypoalbuminemia, high erythrocyte sedimentation rate, and C-reactive protein in order to rule out gastrointestinal pathologies.

New-onset celiac disease in children during COVID-19 pandemic.

AIM: We aimed to analyse the influence of the COVID-19 pandemic on the frequency and clinical presentation of celiac disease. METHODS: The study included the patients with celiac disease since January 2008. They were divided into 2 groups (diagnosed in pre-pandemic [January 2008 and February 2020] [n = 148] and in pandemic period [March 2020 and June 2021] [n = 47]). Clinical and histological findings were compared between groups. Additionally, data about severe acute respiratory syndrome coronavirus 2 infection were obtained in subgroup patients (n = 22) with celiac disease diagnosed during pandemic period. RESULTS: The number of patients per year (12.1-37.6) and the percentage of patients who were diagnosed with celiac disease/total endoscopy were increased during the pandemic period (2.2% vs. 10%, p < 0.00001). The association of celiac disease with type 1 diabetes mellitus was significantly high in pandemic period (4% vs. 17%, p = 0.002). Frequency of moderate-severe mucosal lesions was low in pandemic period (42.4% vs. 81.7%, p = 0.0001). Clinical and laboratory markers for the past severe acute respiratory syndrome coronavirus 2 infection were found in 36.3% of patients diagnosed during the pandemic period. CONCLUSION: It seems that the frequency of celiac disease and its association with type 1 diabetes mellitus is increased during the COVID-19 pandemic in children.

Successful therapeutic plasma exchange in a case with extremely severe hypertriglyceridemia secondary to diabetic ketoacidosis concomitant with type IX glycogen storage disease.

Herein, we aimed to present a child with extremely severe hypertriglyceridemia (ESHTG) secondary to diabetic ketoacidosis concomitant with type IX glycogen storage disease (GSD). Extremely severe hypertriglyceridemia (10 700 mg/dL) was detected through the apparent lipemic appearance of the sampled blood in a 17-year-old male patient with severe diabetic ketoacidosis. In spite of insulin infusion, the patient's clinical condition deteriorated to acute pancreatitis. Single sessions of therapeutic plasma exchange (TPE) along with insulin treatment have successfully intercepted the progression of the state of acute pancreatitis. The patient was also diagnosed with type IX GSD on the basis of the genetic analyses performed for the potential underlying metabolic diseases. In conclusion, underlying metabolic diseases, such as glycogen storage disease, should be investigated in patients with diabetic ketoacidosis accompanied by severe hypertriglyceridemia. If ESHTG does not relieve despite insulin infusion, and/or acute pancreatitis occurs as a complication, TPE should be kept in mind.

Efficiency of azathioprine monotherapy for maintenance treatment of autoimmune hepatitis in children.

INTRODUCTION: Autoimmune hepatitis (AIH) is a common pediatric liver disease and long-term remission is usually maintained with low dose prednisolone and azathioprine (AZA). The aim of this study is to evaluate the efficiency of AZA monotherapy for maintenance treatment of children with AIH. MATERIALS AND METHODS: This study was a retrospective analysis of the 55 children with AIH. Patients were divided into two groups: combination therapy (CT) and AZA group based on maintenance therapy. Results of these two different maintenance treatments were compared in children with AIH. RESULTS: The mean age of the children was 10.67 ± 4.30 years (61.8% females) with a mean follow-up period of 46.8 ± 33.6 months. For maintenance treatment, 39 (70.9%) patients received AZA and 16 (29.1%) patients received CT. Relapse was observed in nine (19.6%) cases in the follow-up period; two were in the CT group (2/16; 12.5%) and seven (7/39; 17.9%) were in the AZA group (P = 0.620). In AZA group, the duration of remission was 22.2 ± 6.1 months and that was longer than CT group (P = 0.025). CONCLUSION: Our study suggests that AZA monotherapy is an effective and safe therapy for maintaining remission in children with AIH. AZA monotherapy may be used for maintenance treatment of children with AIH, except in cases of overlap syndrome and also to avoid side effects of long-term used steroids and to improve treatment compliance in proper cases.

Investigation of phage and molasses interactions for the biocontrol of E. coli O157:H7.

Resistance to antibiotics is one of the most critical health problems in the world. Therefore, finding new treatment methods to be used as alternatives to antibiotics has become a priority for researchers. Similar to phages, certain products containing antimicrobial components, such as molasses, are widely used to eliminate resistant bacteria. Molasses has a strong antimicrobial effect on bacterial cells, and this effect is thought to be due to the breakdown of the cytoplasmic cell membrane and cell proteins of the polyphenols in molasses. In the present study, phage-molasses interactions were investigated to examine the effects of concomitant use. It was found that molasses samples increased the size of phage plaques by up to 3-fold, and MIC and 1/2 × MIC concentrations of molasses increased the burst size of phages. Although no synergistic effect was found between the phage and molasses, the antimicrobial activities of the components and the effect of molasses on phage activity were demonstrated.

Prevalence of celiac disease in children with joint hypermobility.

INTRODUCTION: Generalized joint hypermobility is a clinical feature that is associated with excessive joint laxity, which can occur alone or with various inherited disorders. The term of benign joint hypermobility or joint hypermobility is used when the presence of musculoskeletal symptoms in subjects with generalized joint hypermobility in the absence of demonstrable systemic rheumatic diseases. In recent studies, it was shown that there is a strong relationship between structural and functional gastrointestinal disorders and joint hypermobility. We aimed to analyze the prevalence of celiac disease in a group patient with joint hypermobility. PATIENTS AND METHODS: The study included the 2 groups of children (i) Group 1; patients with joint hypermobility that were followed in pediatric rheumatology outpatient clinic (n=131). (ii) Group 2; healthy children without known chronic diseases (n=995). Demographic features, clinical findings, accompanying symptoms and anthropometric measurements of all patients were recorded. All cases were screened for celiac disease by serological marker and histopathological examinations if serological marker was positive. RESULTS: There was no difference between two groups for age, gender, presence of malnutrition and accompanying symptoms (p>0.05). Serology positivity of anti-tissue transglutaminase IgA >20 RU/ml was found in seven patients with joint hypermobility. After histopathological examinations, asymptomatic celiac disease was detected in one (n=1, 0.9%) and potential celiac disease in six patients (n=6, 5.3%). There were six (0.6%) patients with positive serology in the control group. Celiac serology positivity and potential celiac disease were higher in patients with joint hypermobility (6.2%, vs. 0.6%, OR: 10.9, 95% CI: 3.6-33, p < 0.001 and 5.3%, vs. 0.4%, OR: 13.9, 95% CI: 3.6-50, p < 0.001, respectively), but no significant difference was found on the prevalence of asymptomatic celiac disease (0.9%, vs. 0.2%, OR: 4.4, p=0.22). CONCLUSION: Our study shows the increased prevalence of potential celiac disease in patients with joint hypermobility. Serological screening of celiac disease is recommended for to rule out organic problems in the presence gastrointestinal symptoms in patients with BJH.

Early onset congenital diarrheas; single center experience.

BACKGROUND: Congenital diarrheal disorders (CDDs) are a rare group of enteropathies that typically present in the early few months of life and pose a diagnostic challenge. We aimed to analyze the clinical findings and outcome of infants with CDDs and share experience about genetic testing. METHODS: Demographic, clinical and genetic findings, and outcome of the patients (n = 24) with CDDs were recorded from hospital files. RESULTS: The onset of diarrhea was within the neonatal period in 45.8% of the patients. The most frequent causes of CDDs were defects in digestion, absorption and transport of nutrients and electrolytes (DATN) (n = 11, 45.8%) and defects in intestinal immune-related homeostasis (IIH) (n = 6, 25%). Fat malabsorption (n = 6) was the leading cause of defects in DATN. Extraintestinal manifestations including neurological involvement (25%) and renal involvement (20.8%) were common among the patients. Genetic analyses were performed for 16 patients (targeted gene analysis in 9, congenital diarrhea panel in 3, immune deficiency panel in 1 and whole-exome sequencing in 3 patients). Genetic diagnosis was achieved in 14 of 16 patients (87.5%) with therapeutic consequences in 8 of 16 patients (50%). During the follow-up, 6 patients (25%) died. CONCLUSION: The percentage of undefined etiology decreased, and treatment of the patients improved with the increased number of genetic testing in patients with CDDs.

The first pediatric case of hemophagocytic lymphohistiocytosis secondary to Crimean-Congo haemorrhagic fever successfully treated with therapeutic plasma exchange accompanying ribavirin and intravenous immunoglobulin.

Although Crimean-Congo hemorrhagic fever (CCHF) is mild and self-limited in children, some patients may develop excessive bleeding, massive liver necrosis, and multiple organ failure associated with secondary hemophagocytic lymphohistiocytosis (HLH) induced by cytokine storm. Treatment of CCHF is mainly symptomatic and supportive. The efficacy of ribavirin, which is the only antiviral drug in the treatment of CCHF, remains controversial. Although therapeutic plasma exchange (TPE) has been shown to beneficial in small case series with primary and secondary HLH, there is no pediatric patient with HLH secondary to CCHF treated with TPE in the literature. In this report, we describe the first pediatric patient who was successfully recovered from HLH secondary to CCHF with ribavirin, intravenous immunoglobulin, and TPE.

Comparison of clinical outcomes and FOXP3, IL-17A responses in Helicobacter pylori infection in children versus adults.

BACKGROUND: The purpose of this study was to compare the clinical symptoms and pathological consequences of Helicobacter pylori (H. pylori) infection between children and adults and determine the levels of expression of FOX3P and IL-17A to examine the Th17/Treg balance. METHODS: Forty pediatric and 40 adult patients who were followed up at the Pediatric Gastroenterology and Internal Medicine Gastroenterology Departments were enrolled in the study. In our case-control study, gastric tissue specimens were evaluated using the updated Sydney system, and the number of cells expressing FOXP3/IL-17A (Treg and Th17 cell markers) was analyzed immunohistochemically. In addition, each case was evaluated using a clinical follow-up questionnaire. RESULTS: Clinical signs and symptoms of children and adults were similar. IL-17A and FOXP3 levels were significantly higher in children and adults with H. pylori (+) than in those without H. pylori (-) (p < .001). In patients with H. pylori (+), the mean FOXP3 level was significantly higher, whereas the mean IL-17A level was significantly lower in children than in adults (p < 0001 for both groups). In children with H. pylori (+), bacterial density was negatively correlated with IL-17A level and positively correlated with FOXP3 level. In adults with H. pylori (+), there was a statistically significant, highly positive correlation between bacterial density and levels of IL-17A and FOXP3. CONCLUSIONS: Treg cells are suggested to more predominant in children than in adults, IL-17A levels decrease as H. pylori bacterial density increases. In conclusion, immune responses incline toward Treg , which increases the susceptibility to persistent infections.

Fecal elastase levels in children diagnosed with functional abdominal pain-not otherwise specified.

BACKGROUND: Although the exact pathophysiology of functional gastrointestinal diseases remains unclear, numerous etiologies have been blamed, including visceral hypersensitivity, gastrointestinal motility disorders, psychological factors, intestinal mucosal inflammation, intestinal microbiota, and post-infectious syndromes. In the present study, we aimed to evaluate pancreatic insufficient patients diagnosed with functional abdominal pain-not otherwise specified (FAP-NOS) according to Rome IV criteria. METHODS: The study included a total of 110 patients aged 4-17 years who were diagnosed with FAP-NOS according to Rome IV criteria. The control group consisted of 80 patients with no gastrointestinal disorders and chronic diseases. Glucose, amylase, lipase, pancreatic amylase, immunoreactive trypsinogen (IRT) and fecal elastase (FE-1) levels were examined for each patient. RESULTS: No significant difference was found between the two groups with regard to lipase, pancreatic amylase, IRT, and serum glucose levels. However, the amylase levels were significantly higher and the FE-1 levels were significantly lower in the study group compared to the control group (p=0.007 and p < 0.001). The cut-off value detected in in ROC analysis for the diagnostic value of FE-1 in predicting FAP-NOS was found to be 140.107 µg/g. Based on this value, the sensitivity, specificity, PPV, and NPV of FE-1 were 82.1%, 66.2%, 77%, 73%, respectively. Accordingly, the likelihood of FE-1 in providing a positive value in patients with FAP-NOS was almost 9 times higher than in individuals without FAP-NOS. CONCLUSIONS: FE-1 levels were significantly lower in children diagnosed with FAP-NOS and we consider that this difference could be attributed to malabsorption secondary to dysbiosis as there is not enough data.

Altered von Willebrand Factor and ADAMTS13 Levels in Children With Cirrhosis and Extrahepatic Portal Hypertension.

BACKGROUND/AIM: This study was concerned with whether vWF (von Willebrand factor) and a disintegrin and metalloprotease with a thrombospondin type 1 motif, member 13 (ADAMTS13) has altered in patients with cirrhosis and extrahepatic portal hypertension (EPH). We aimed to investigate changes to vWF and ADAMTS13 in children with cirrhosis and EPH. PATIENTS AND METHODS: This study was conducted between January and October 2019 with both cirrhosis and EPH patients and with healthy volunteers. The von Willebrand factor antigen (vWF:Ag), von Willebrand Ristocetin cofactor (vWF:RCo), and ADAMTS13 antigen and activity were studied. RESULTS: Twenty-eight children with cirrhosis, 16 children with EPH, and 20 healthy controls were included in the study. vWF:Ag and vWF:RCo levels were higher in patients with cirrhosis than in healthy controls (171.65±101.67 vs. 85.86±30.58, P<0.01 and 121.62±55.83 vs. 61.52±27.03, P<0.01, respectively). vWF:Ag and vWF:RCo levels were higher in patients with EPH than in healthy controls (133.93±80.13 vs. 85.86±30.58, P<0.01 and 103.18±58.55 vs. 61.52±27.03, P=0.02, respectively). The ADAMTS13 antigen and activity levels were lower in patients with cirrhosis than in healthy controls (0.58±0.23 vs. 0.97±0.15, P<0.01 and 49.91±22.43 vs. 86.51±22.07, P=0.02, respectively). The ADAMTS13 antigen and activity levels were lower in patients with EPH than in healthy controls (0.69±0.11 vs. 0.97±0.15, P=0.03; and 68.50±13.29 vs. 86.51±22.07, P=0.02, respectively). The increase in vWF and the decrease in ADAMTS13 were more pronounced in cirrhotic patients with autoimmune hepatitis (AIH) than in non-AIH patients. CONCLUSIONS: While levels of vWF:Ag and vWF:RCo increased in children with cirrhosis and EPH, levels of the ADAMTS13 antigen and ADAMTS13 activity decreased. These alterations were more pronounced in patients with AIH-derived cirrhosis.

A disposable gold-cellulose nanofibril platform for SERS mapping.

In this study, we present a disposable and inexpensive paper-like gold nanoparticle-embedded cellulose nanofibril substrate for the rapid enumeration of Escherichia coli (E. coli) using surface-enhanced Raman scattering (SERS) mapping. A disposable SERS substrate was simply constructed by mixing CNF and gold chloride solution at 120 °C in a water bath. The application of the resulting substrate was carried out by enrichment and SERS detection of E. coli. To this end, the spherical gold nanoparticle-embedded cellulose nanofibril substrate was used as a scavenger for E. coli. After the target bacteria E. coli were separated from the matrix via oriented antibodies, the sandwich assay procedure was carried out using 5,5-dithiobis-(2-nitrobenzoic acid) (DTNB)-coated Au nanorod particles that acted as SERS mapping probes. The distribution density of DTNB was demonstrated visually using SERS mapping, and the assay was completed in one hour. The correlation between the E. coli and SERS mapping signals was found to be linear within the range of 15 cfu mL-1 to 1.5 × 105 cfu mL-1. The limit of detection for the SERS mapping assay was determined to be 2 cfu mL-1. The selectivity of the developed method was examined with Micrococcus luteus (M. luteus), Bacillus subtilis (B. subtilis), and Enterobacter aerogenes (E. aerogenes), which did not produce any significant response. Furthermore, the developed method was evaluated for detecting E. coli in artificially contaminated samples, and the results were compared with those of the plate-counting method.

Effectivity of Pancreatic Enzyme Replacement Therapy in Malnourished Children.

OBJECTIVE: Malnutrition is commonly seen in children with exocrine pancreatic insufficiency (EPI). Pancreatic enzyme replacement therapy (PERT) is the mainstay treatment of acute malnutrition in children detected with a disease closely associated with EPI (eg, cystic fibrosis). The effectiveness of PERT in children with malnutrition without any chronic disease, however, remains unclear. The aim of this study was to investigate the effectiveness of PERT on weight gain and EPI in children classified as moderately and severely malnourished according to the World Health Organization (WHO) classification. MATERIALS AND METHODS: The study included a total of 40 children aged 2-16 years who were classified as moderately and severely malnourished according to the WHO classification. The patients were randomly divided into 2 groups: PERT group (n = 20) received 2000 U lipase/kg/day (in 4 doses) in addition to hypercaloric enteral supplements and control group received hypercaloric enteral supplements only. In both groups, anthropometric measurements and the assessment of fecal elastase-1 (FE-1) levels were performed both at first admission and at the end of the 8-week treatment period. RESULTS: On the basis of WHO classification, 10 (25%) children were classified as severely malnourished and 30 (75%) children as moderately malnourished. EPI was detected in all the patients, among whom 24 (60%) patients had severe EPI. At the end of the treatment, body weight, height, and body mass index (BMI) increased significantly in both groups compared to their pre-treatment values, whereas no significant difference was found with regard to waist circumference (WC) and FE-1 levels. Similarly, no significant difference was found between pre- and posttreatment measurements of PERT and control groups (P > 0.05) and between pre- and posttreatment measurements of patients with moderate and severe malnutrition (P > 0.05). CONCLUSIONS: Malnutrition remains a serious public health problem, and thus, the development of novel treatment methods is highly essential. PERT is one of the most commonly considered alternatives, although there is little documentation of PERT in the literature. In the present study, although PERT resulted in higher weight gain, it established no significant difference between the 2 groups.

Immunomagnetic separation and Listeriamonocytogenes detection with surface-enhanced Raman scattering

Background/aim: We aimed to develop a rapid method to enumerate Listeria monocytogenes (L. monocytogenes) utilizing magnetic nanoparticle based preconcentration and surface-enhanced Raman spectroscopy measurements. Materials and methods: Biological activities of magnetic Au-nanoparticles have been observed to have the high biocompatibility, and a sample immunosensor model has been designed to use avidin attached Au-nanoparticles for L. monocytogenes detection. Staphylococcus aureus (S. aureus) and Salmonella typhimurium (S. typhimurium) bacteria cultures were chosen for control studies. Antimicrobial activity studies have been done to identify bio-compatibility and bio-characterization of the Au-nanoparticles in our previous study and capturing efficiencies to bacterial surfaces have been also investigated. Results: We constructed the calibration graphs in various population density of L. monocytogenes as 2.2 × 101 to 2.2 × 106 cfu/mL and the capture efficiency was found to be 75%. After the optimization procedures, population density of L. monocytogenes and Raman signal intensity showed a good linear correlation (R2 = 0.991) between 102 to 106 cfu/mL L. monocytogenes. The presented sandwich assay provides low detection limits and limit of quantification as 12 cfu/mL and 37 cfu/mL, respectively. We also compared the experimental results with reference plate-counting methods and the practical utility of the proposed assay is demonstrated using milk samples. Conclusion: It is focused on the enumeration of L. monocytogenes in milk samples and the comparision of results of milk analysis obtained by the proposed SERS method and by plate counting method stay in food agreement. In the present study, all parameters were optimized to select SERS-based immunoassay method for L. monocytogenes bacteria to ensure LOD, selectivity, precision and repeatablity.

Surface enhanced Raman spectroscopy as a novel tool for rapid quantification of heroin and metabolites in saliva

Background: Heroin can be detected and quantified by certain analytical methods, however, forensic professionals and criminal laboratories study for cheaper and faster detection tools. Surface-enhanced Raman spectroscopy (SERS) rises as a possible alternative tool with its widening application spectra. There are few studies regarding Raman and SERS spectra of heroin and its metabolites, which are unfortunately controversial. In this study, we compared five different surfaces in order to find out more efficient Raman-active substrate for opiate detection and rapid quantification of heroin and its metabolites in saliva. Materials and methods: Morphine standard material was used to identify proper surface for SERS analysis of opiates. Heroin and its metabolites (morphine, morphine-3-ß-glucuronide and 6-monoacetyl morphine) were calibrated between 50 ppb and 500 ppm and quantified on AuNRs with signal enhancement of silver colloids in saliva. Raman microscope with a 785-nm laser source was used. Results and Conclusion: Obtained results showed that heroin and its metabolites can be detected and quantified in saliva samples using a SERS-based system. Additionally, the present study revealed that synergetic effect of a specific gold nano-surface with ability controlling liquid motion and silver nanoparticles increase band numbers and intensities. Therefore, we suggest a fast, accurate and cost-effective method to detect and quantify heroin in biological fluids