Development of an Immunochromatographic Strip Using Conjugated Gold Nanoparticles for the Rapid Detection of Klebsiella pneumoniae Causing Neonatal Sepsis.

Neonatal sepsis is a leading cause of death among newborns and infants, especially in the developing world. The problem is compounded by the delays in pinpointing the causative agent of the infection. This is reflected in increasing mortality associated with these cases and the spread of multi-drug-resistant bacteria. In this work, we deployed bioinformatics and proteomics analyses to determine a promising target that could be used for the identification of a major neonatal sepsis causative agent, Klebsiella pneumoniae. A 19 amino acid peptide from a hypothetical outer membrane was found to be very specific to the species, well conserved among its strains, surface exposed, and expressed in conditions simulating infection. Antibodies against the selected peptide were conjugated to gold nanoparticles and incorporated into an immunochromatographic strip. The developed strip was able to detect as low as 105 CFU/mL of K. pneumoniae. Regarding specificity, it showed negative results with both Escherichia coli and Enterobacter cloacae. More importantly, in a pilot study using neonatal sepsis cases blood specimens, the developed strip selectively gave positive results within 20 min with those infected with K. pneumoniae without prior sample processing. However, it gave negative results in cases infected with other bacterial species.

Clinical Characteristics of Preterm Neonates with Aggressive Posterior Retinopathy of Prematurity.

PURPOSE: We aimed to identify the risk factors that may predispose preterm neonates to develop aggressive posterior retinopathy of prematurity (APROP). METHODS: This retrospective case control study included 16 infants with APROP in zone 1 or posterior zone 2. Thirty-four gestational age and birth weight-matched controls with stage 2 or less ROP were included. We reviewed medical records on infant birth and postnatal characteristics. RESULTS: Patients who developed APROP had a significantly longer duration of caffeine therapy, were significantly more likely to be small for gestational age (SGA), and were more likely to have a positive blood culture than patients who developed less severe ROP. Patients with APROP who required retreatment had received inotropes for a longer duration of time, had received more plasma transfusions, were more likely to have IVH, and had a greater decrease in the serum hemoglobin during hospitalization. CONCLUSION: Being SGA, receiving caffeine for a longer duration, and having culture-proven sepsis were associated with APROP. IVH, a low serum hemoglobin, the need for more plasma transfusions, and a longer duration of inotropes were associated with APROP which required retreatment.

A Novel Surface-Exposed Polypeptide Is Successfully Employed as a Target for Developing a Prototype One-Step Immunochromatographic Strip for Specific and Sensitive Direct Detection of Staphylococcus aureus Causing Neonatal Sepsis.

Neonatal sepsis is a life-threatening condition and Staphylococcus aureus is one of its major causes. However, to date, no rapid and sensitive diagnostic tool has been developed for its direct detection. Bioinformatics analyses identified a surface-exposed 112-amino acid polypeptide of the cell wall protein NWMN_1649, a surface protein involved in cell aggregation and biofilm formation, as being a species-specific and highly conserved moiety. The polypeptide was cloned, purified, and used to immunize mice to raise specific immunoglobulins. The purified antibodies were conjugated to gold nano-particles and used to assemble an immunochromatographic strip (ICS). The developed prototype ICS detected as low as 5 µg purified polypeptide and 102 CFU/mL S. aureus within 15 min. The strip showed superior ability to directly detect S. aureus in neonatal sepsis blood specimens without prior sample processing. Moreover, it showed no cross-reaction in specimens infected with two other major causes of neonatal sepsis; coagulase-negative staphylococci and Klebsiella pneumoniae. The selected NWMN_1649-derived polypeptide demonstrates success as a promising biomolecule upon which a prototype ICS has been developed. This ICS provides a rapid, direct, sensitive, and specific option for the detection of S. aureus causing neonatal sepsis. Such a tool is urgently needed especially in resources-limited countries.

Retrospective cohort study shows that the risks for retinopathy of prematurity included birth age and weight, medical conditions and treatment.

AIM: This study described the characteristics and risk factors of neonates who developed retinopathy of prematurity (ROP) and severe treatable ROP in two Egyptian neonatal intensive care units (NICUs). METHODS: This retrospective cohort study comprised 108 preterm neonates who were screened for ROP after being admitted to the two NICUs run by Cairo University Hospital from June 2014 to May 2015. Patients were examined using digital fundus photography and indirect ophthalmoscopy was performed if ROP was detected. RESULTS: Retinopathy of prematurity occurred in 75 patients. Late-onset sepsis, ventilation and hypercapnia were independently associated with ROP. Patients who developed severe treatable ROP had a younger gestational age (GA) than patients who did not develop ROP or developed mild or moderate ROP (29 weeks, range 27-33 weeks versus 32 weeks, range 28-36 weeks, p = 0.002) and a lower birthweight (1200 g, range 980-1590 g versus 1460 g, range 770-2475 g, p = 0.029). The risk factors associated with severe treatable ROP included the duration of admission, the duration of incubator oxygen, late-onset sepsis, intraventricular haemorrhage, total parenteral nutrition and the duration of caffeine citrate therapy. CONCLUSION: This study showed that the risks for ROP were wide-ranging and included GA and weight, medical conditions and treatment.

Polymorphisms of Vascular Endothelial Growth Factor and Retinopathy of Prematurity.

PURPOSE: Retinopathy of prematurity (ROP) is a major problem among preterm survivors of neonatal intensive care. Neovascularization of the retina is prominent in the proliferative stages of ROP and is under the control of factors such as vascular endothelial growth factor (VEGF). The authors investigated the association of ROP with VEGF genetic polymorphisms and clinical (maternal, perinatal, neonatal) risk factors among preterm infants admitted to the neonatal intensive care unit. METHODS: The frequencies of VEGF 634 C/G and VEGF 936 C/T polymorphisms were determined in DNA from 102 preterm infants by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique. RESULTS: The frequency of the VEGF 634 CG genotype was significantly higher, whereas the frequency of the VEGF 634 CC genotype was significantly lower among neonates with ROP. The frequencies of the VEGF 634 GG, VEGF 936 CC, and VEGF 936 CT genotypes were similar in both groups. The distribution of VEGF 634 G allele was significantly different between the two groups. By logistic regression analysis, low birth weight, presence of maternal disease, respiratory distress syndrome, hypotension, and VEGF 634 CG genotype remained significant risk factors for the development of ROP. CONCLUSIONS: The results support the hypothesis that the carrier state of VEGF 634 C/G polymorphism has an impact on the risk of ROP in infants. A broader study may suggest that this marker could be used as an indicator in the screening for ROP.

Profile of cystic fibrosis in a single referral center in Egypt.

It was generally believed that Cystic fibrosis (CF) is rare among Arabs; however, the few studies available from Egypt and other Arabic countries suggested the presence of many undiagnosed patients. The aim of the present study was to determine the frequency of CF patients out of the referred cases in a single referral hospital in Egypt. A total of 100 patients clinically suspected of having CF were recruited from the CF clinic of the Allergy and Pulmonology Unit, Children's Hospital, Cairo University, Egypt, throughout a 2 year period. Sweat chloride testing was done for all patients using the Wescor macroduct system for collection of sweat. Quantitative analysis for chloride was then done by the thiocyanate colorimetric method. Patients positive for sweat chloride (⩾60 mmol/L) were tested for the ΔF508 mutation using primer specific PCR for cystic fibrosis transmembrane conductance regulator (CFTR) gene. Thirty-six patients (36%) had a positive sweat chloride test. The main clinical presentations in patients were chronic cough in 32 (88.9%), failure to thrive in 27 (75%), steatorrhea in 24 (66.7%), and hepatobiliary involvement in 5 (13.9%). Positive consanguinity was reported in 50% of CF patients. Thirty-two patients were screened for ΔF508 mutation. Positive ΔF508 mutation was detected in 22 (68.8%) patients, 8 (25%) were homozygous, 14 (43.8%) were heterozygous, and 10 (31.3%) tested were negative. CF was diagnosed in more than third of patients suspected of having the disease on clinical grounds. This high frequency of CF among referred patients indicates that a high index of suspicion and an increasing availability of diagnostic tests lead to the identification of a higher number of affected individuals.

Frequency of Helicobacter pylori infection among Egyptian children presenting with gastrointestinal manifestations.

BACKGROUND AND AIMS: Recurrent abdominal pain (RAP) and other gastrointestinal (GI) symptoms are common complaints among children. The role of Helicobacter pylori in the causation of these complaints remains controversial. The aim of this study was to determine the frequency of H. pylori infection among children presenting with GI manifestations and to determine the most common clinical presentation of the infection in Egyptian children. PATIENTS AND METHODS: This prospective cross-sectional study included 150 consecutive patients aged 5-15 years who presented to the outpatient clinic of Cairo University's Specialized Pediatric Hospital with GI complaints. Screening for H. pylori infection was performed using a 13C-urea breath test (13C-UBT), and in patients whose 13C-UBT was positive, diagnosis was confirmed by visualizing the bacterium in biopsy specimens obtained by GI endoscopy. RESULTS: RAP was the most frequent GI complaint of the study population (82%), followed by anorexia (6.7%), vomiting (6.7%), and chronic diarrhea (4.7%). Seventy percent of these patients were positive for the 13C-UBT. Ninety-one of the patients who complained of RAP had a positive 13C-UBT, whereas the remaining 32 patients who had RAP had a negative 13C-UBT, a difference that was statistically significant (P=0.023). However, no statistically significant differences were found between the 13C-UBT result among patients with anorexia, vomiting, or diarrhea (P=0.153, 1.00, and 0.447, respectively). CONCLUSION AND RECOMMENDATIONS: Screening for H. pylori infection should be performed for school-aged children who have GI complaints, especially for those who complain of RAP.

Morbidity and outcome of severe respiratory syncytial virus infection.

BACKGROUND: Respiratory syncytial virus (RSV) is the main cause of severe acute respiratory infection (SARI) in infants and young children. This study aimed to identify risk factors for intensive care unit (ICU) admission, prolonged length of stay (PLOS), and mortality in patients hospitalized with SARI caused by RSV. METHODS: This prospective cohort study included children hospitalized with SARI (according to the World Health Organization definition) and whose laboratory results proved RSV infection during the period from February 2010 to May 2011. RESULTS: Out of 240 enrolled patients, 24 patients (10%) were admitted to the ICU, 57 patients (24.3%) had a PLOS of >9 days and 12 patients (5%) died. The presence of cyanosis (P = 0.000; OR, 351.7) and lung consolidation (P = 0.006, OR, 9.3) were independent risk factors associated with ICU admission. The need for ICU admission (P = 0.000; OR, 6.1) and lung consolidation (P = 0.008, OR, 2.46) were independent risk factors associated with PLOS. The presence of an underlying congenital heart disease (P = 0.03, OR, 18.3), thrombocytopenia (P = 0.04, OR, 32.86) and mechanical ventilation (P = 0.000; OR, 449.4) were the only independent risk factors associated with mortality in our study. CONCLUSIONS: Early recognition of risk factors for complicated RSV disease on admission prompts early interventions and early ICU admissions for these children.

Empirical antibiotic treatment and the risk of necrotizing enterocolitis and death in very low birth weight neonates.

BACKGROUND AND OBJECTIVES: Antibiotics are one of the most overused drugs in the neonatal unit. Our objective was to assess associations between the duration of the initial antibiotic course and subsequent necrotizing enterocolitis (NEC) and/or death in very low birth weight (VLBW) neonates with sterile initial postnatal culture results. DESIGN AND SETTING: A retrospective cohort analysis of VLBW neonates admitted to a tertiary center during the period from 1 January 2008 to 31 december 2009. PATIENTS AND METHODS: The study included VLBW neonates who had been inborn and admitted to the neonatal intensive care unit within the first 24 hours after birth. We used descriptive statistics to characterize the study population, and multivariate analyses to evaluate associations between therapy duration, prolonged empirical therapy, and subsequent NEC and/or death. RESULTS: Of 328 VLBW neonates admitted to our center, 207 (63%) survived >5 days and received initial empirical antibiotic treatment for ≥5 days. The median duration of initial empirical antibiotic therapy was 7 days (range 5-10 days). those neonates were more likely to be of younger gestational age, lower birth weight, and to have lower Apgar scores (P<.001, .001 and .017, respectively). each empirical treatment day was associated with increased odds of death (or 1.45, CI 1.24-1.69), NEC (or 1.32, CI 1.05-1.65), and the composite measure of NEC or death (or 2.13, CI 1.55-2.93). CONCLUSION: The use of prolonged initial empirical antibiotic therapy in VLBW neonates with initial sterile culture results may be associated with an increased risk of NEC or death and should be used with caution.

The role of PTPN22 gene polymorphism in childhood immune thrombocytopenic purpura.

Immune thrombocytopenia is an autoimmune disorder characterized by antibody-mediated platelet destruction. A protein tyrosine phosphatase (PTPN22) present in lymphocytes is an important negative regulator of signal transduction for the T-cell receptor-MHC complex and has been associated with autoimmune disorders that produce autoantibodies. The present study investigated the frequency of the 1858C>T single-nucleotide polymorphism (SNP) in the PTPN22 gene in idiopathic thrombocytopenic purpura (ITP) patients. This case series study included 50 children with ITP, 24 acute and 26 chronic cases, and 50 normal children as a control group. All were subjected to clinical history and laboratory investigations including complete blood count, genotyping of PTPN22 1858C/T SNP by polymerase chain reaction-restriction fragment length polymorphism and platelet antibodies using platelets suspension immunofluorescence test for the cases. Thirteen patients (26%) were positive for the PTPN22 1858C>T SNP. Three patients were homozygous for the mutation and 10 were heterozygous. Comparison of the 26% of the ITP patients who were positive for the PTPN22 1858C>T mutation with the 6% positive in the control group yielded a P value of 0.006. Antiplatelet antibodies were detected in five patients (20.8%) with acute ITP and in three patients (11.5%) with chronic ITP; no significant association between the presence of PTPN22 1858C>T mutation and the presence of antiplatelet antibodies was detected. The prevalence of PTPN22 gene mutation was higher in ITP patients, thus it may be considered as a genetic risk factor in the development of ITP in Egyptian children.