Changing Epidemiology and Antimicrobial Resistance of Bacterial Childhood Diarrhea: Insights from a 7-Year Study in an Iranian Referral Hospital.

Acute gastroenteritis (AGE) poses a significant public health challenge for children in developing countries. Considering the high prevalence of AGE in Iranian children, the aim of this study was to investigate and analyze the patterns and changes in bacterial identification as well as antibiotic resistance in AG over the course of 7 years. From January 2015 to December 2021, a total of 15,300 pediatric patients with AGE were admitted to the Children's Medical Center, an Iranian academic referral hospital, Tehran, Iran. Among these cases, 8.9% (1329 individuals) yielded positive stool cultures. The predominant bacterial etiology of AGE was identified as Shigella sonnei (n = 424, 31.9%), and Salmonella group D (n = 367, 27.6%), followed by Shigella flexneri: 16.3% (217 cases), Salmonella group C (n = 152, 11.4%), Salmonella group B (n = 91, 6.8%), Escherichia coli (n = 65, 4.9%), Shigella boydii (n = 10, 0.75%), and Shigella dysenteriae (n = 3, 0.2%). Notably, S. sonnei exhibited high resistance rates to trimethoprim-sulfamethoxazole (97.6%) and nalidixic acid (95.3%). S. flexneri and S. boydii isolates displayed significant resistance to ampicillin (96.8% and 88.9%, respectively). Salmonella group D demonstrated elevated resistance to ciprofloxacin (81.3%) and nalidixic acid (88.5%), with notable sensitivity to trimethoprim-sulfamethoxazole and cefotaxime (97.3% and 97.5%, respectively). E. coli displayed resistance rates of 80%, 74%, and 66% to trimethoprim-sulfamethoxazole, cefotaxime, and ciprofloxacin, respectively. The fluctuating prevalence of S. sonnei and Salmonella group D, two predominant bacterial isolates associated with AGE, underscores the dynamic nature of these pathogens. The notable increase in antibiotic resistance observed in S. sonnei raises concerns, underscoring the critical need for judicious and careful antibiotic use.

Comparing the effect of cardiac biomarkers on the outcome of normotensive patients with acute pulmonary embolism.

Acute pulmonary embolism (PE) is a cardiovascular challenge with potentially fatal consequences. This study was designed to observe the association of novel cardiac biomarkers with outcome in this setting. In this prospective study, from 86 patients with a confirmed diagnosis of PE, 59 patients met the inclusion criteria (22 men, 37 women; mean age, 63.36±15.04 y).The plasma concentrations of N-terminal pro-brain natriuretic peptide (NT-proBNP), growth differentiation factor-15 (GDF-15), heart-type fatty acid-binding protein (H-FABP), tenascin-C, and D-dimer were measured at the time of confirmed diagnosis. The endpoints of the study were defined as the short-term adverse outcome and long-term all-cause mortality. Totally, 11.8% (7/59) of the patients had the short-term adverse outcome. The mean value of logNT-proBNP was 6.40±1.66 pg/ml. Among all the examined biomarkers, only the mean value of logNT-proBNP was significantly higher in the patients with the short-term adverse outcome (7.88±0.67 vs. 6.22± 1.66 pg/ml; OR, 2.359; 95% CI, 1.037 to 5.367; P=0.041). After adjustment, a threefold increase in the short-term adverse outcome was identified (OR, 3.239; 95% CI, 0.877 to 11.967; P=0.078).Overall, 18.64% (11/59) of the patients had expired by the long-term follow-up. Moreover, adjustment revealed an evidence regarding association between increased logNT-proBNP levels and long-term mortality (HR, 2.163; 95%CI, 0.910 to 5.142; P=0.081). Our study could find evidences on association between increased level of NT-proBNP and short-term adverse outcome and/or long-term mortality in PE. This biomarker may be capable of improving prediction of outcome and clinical care in non-high-risk PE.

Post-discharge follow-up of pediatric COVID-19 patients: insights into serological dynamics.

Introduction: Limited data are available regarding SARS-CoV-2 serological response dynamics in pediatric patients with COVID-19, contributing to gaps in our understanding of the immune response in this population. This study aimed to investigate SARS-CoV-2 IgG seropositivity in patients diagnosed with COVID-19 during hospitalization and 2-4 weeks after discharge. Methods: A cohort of patients, consisting of 31 individuals with confirmed acute COVID-19 infection and 27 diagnosed with Multisystem Inflammatory Syndrome in Children (MIS-C), was enrolled in the study. Follow-up clinic appointments were scheduled for 2-4 weeks post-discharge. During admission and follow-up, blood samples were collected from each patient for laboratory analysis. Anti-nucleoprotein SARS-CoV-2 IgG levels were determined using the Enzyme-Linked Immunosorbent Assay (ELISA) method. Results: In this study, a cohort of 58 patients was examined. At admission, 52% (n = 14) of MIS-C patients and 10% (n = 3) of acute COVID-19 patients had positive SARS-CoV-2 IgG test. Only 48 cases were referred to the hospital, and follow-up data was available for 20 cases with MIS-C and 28 cases with acute COVID-19. All patients (n = 15) who initially tested positive for SARS-CoV-2 IgG at admission remained positive serology during follow-up (100%). Among the 33 patients who initially tested negative, 12 (37.5%) showed a positive serology result during follow-up, while 21 (62.5%) remained negative. Within this subgroup, 11 cases (44%) were diagnosed with acute COVID-19, and one patient (12.5%) presented with MIS-C. Fourteen cases with acute COVID-19 infection (56%) and seven cases with MIS-C (87.5%) consistently showed negative serology results throughout the study. During follow-up, the median lymphocyte count demonstrated a significant difference, with 0.96 × 109 cells per L (IQR: 0.75-3.0 × 109 cells per L) in the SARS-CoV-2 IgG-negative group and 2.9 × 109 cells per L (IQR = 1.33-7.22 × 109 cells per L) in the SARS-CoV-2 IgG-positive group (p-value = 0.03). Patients who demonstrated seropositivity during the follow-up were associated with a notably severe disease (p-value = 0.028). Conclusion: Our study highlights the dynamic nature of SARS-CoV-2 IgG antibody responses in pediatric patients with COVID-19 infection. We observed a notable increase in seropositivity rates during follow-up. Furthermore, patients who were seropositive at follow-up demonstrated a severe disease course and lower lymphocyte counts compared to those with persistently negative serology. Our findings underscore the importance of longitudinal serological monitoring in understanding disease progression and immune response dynamics in pediatric COVID-19 cases.

Measles immunity status in Iranian infants and children and outbreak concerns: Time for reconsidering the vaccination schedule?

INTRODUCTION: Measles vaccination has greatly reduced the disease burden worldwide, but challenges remain due to variations in vaccine effectiveness across age groups. This study aimed to assess the serological profile of measles antibodies across different age groups, evaluate the impact of maternal immunity on antibody levels in infants under 12 months, and assess measles immunity in vaccinated individuals. MATERIAL AND METHODS: This cross-sectional study was conducted from June 2022 to January 2023 at the Children's Medical Center, a referral hospital in Iran. Serum samples were tested for measles-specific IgG and IgM antibodies using a commercial enzyme-linked immunosorbent assay (ELSA). An avidity assay was performed to assess measles virus-specific IgG antibodies on the samples that were positive and borderline for the measles IgG ELISA. RESULTS: The study included 969 participants across various age groups. Among them, 23% (221 out of 953) tested positive for measles IgM ELISA, and 52% (504 out of 969) for measles IgG ELISA. Regarding the avidity assay for measles virus-specific IgG, the majority (418 out of 573, 73%) showed high-avidity antibodies. Measles-specific IgG levels varied significantly across different age groups, with infants below 6 months old showing a mean IgG level of 477 mIU/mL, declining to 230 mIU/mL between 6 and 12 months, and increasing significantly to 683 mIU/mL in the 12 to 18 month age group, reaching a peak at 938 mIU/mL among children aged 18-72 months. CONCLUSION: The increasing IgM positivity among young Iranians suggests a rising risk of measles outbreaks, possibly due to vaccination gaps. Inadequate antibody levels in infants raise concerns about vaccination effectiveness. Considering declining maternal antibodies, vaccinating infants at 6-9 months could be beneficial. Boosters for adolescents and women may further mitigate outbreak risks.

Molecular Diagnosis of COVID-19; Biosafety and Pre-analytical Recommendations.

From the beginning of the COVID-19 epidemic, clinical laboratories around the world have been involved with tests for detection of SARS-CoV-2. At present, RT-PCR (real-time reverse transcription polymerase chain reaction assay) is seen as the gold standard for identifying the virus. Many factors are involved in achieving the highest accuracy in this test, including parameters related to the pre-analysis stage. Having instructions on the type of sample, how to take the sample, and its storage and transportation help control the interfering factors at this stage. Studies have shown that pre-analytical factors might be the cause of the high SARS-CoV-2 test false-negative rates. Also, the safety of personnel in molecular laboratories is of utmost importance, and it requires strict guidelines to ensure the safety of exposed individuals and prevent the virus from spreading. Since the onset of the outbreak, various instructions and guidelines have been developed in this field by the institutions and the Ministry of Health of each country; these guidelines are seriously in need of integration and operation. In this study, we try to collect all the information and research done from the beginning of this pandemic in December 2019 - August 2022 concerning biosafety and protective measures, sample types, sampling methods, container, and storage solutions, sampling equipment, and sample storage and transportation for molecular testing of SARS-CoV-2.

Diagnostic value of interferon-gamma assay in tuberculosis pericardial effusions: study on a cohort of Iranian patients.

Tuberculosis pericarditis as a potentially fatal complication of tuberculosis requires effective diagnosis and treatment. We evaluated the efficacy of interferon-gamma (IFN-gamma) and adenosine deaminase (ADA) for diagnosing tuberculosis pericarditis in a cohort of Iranian patients presenting with pericarditis. We enrolled 38 patients with presentation of pericarditis. All patients underwent diagnostic and therapeutic pericardiostomy with drainage and biopsy. Adenosine deaminase and interferon-gamma levels were determined in pericardial fluid samples of all patients. Pericardial tissue samples were submitted for histopathologic and microbiologic studies. Polymerase chain reaction (PCR) was performed on all pericardial fluid samples to detect Mycobacterium tuberculosis. From 38 patients with pericarditis, 7 cases were diagnosed as having tuberculosis pericarditis (18.4%). Mean concentration of interferon-gamma in tuberculosis group was significantly higher compared to non-tuberculosis group (69257 pg/l [range: 26600-148000] vs. 329 pg/l [range: 0-2200], P<0.000). Receiver operating characteristic (ROC) curve showed a value of 14400 pg/l as the cutoff point with a sensitivity of 100% and specificity of 100% for diagnosing tuberculosis pericardial effusion. Adenosine deaminase was not found to be significantly higher in tuberculosis group in comparison with non-tuberculosis causes of pericardial effusion (35.7 [range: 9-69] vs. 36.03 [range: 8-420], P=0.28). In this study interferon-gamma showed to be a valuable diagnostic test for detection of tuberculosis pericarditis among a cohort of Iranian patients. We suggest using interferon-gamma to diagnose tuberculosis pericarditis to make diagnose in case of suspicion. While in this study, adenosine deaminase measurement did not prove to have the characteristics of an accurate diagnostic test for tuberculosis pericarditis.