Neena Kanwar

Head-to-head comparison of the diagnostic accuracies of BD Veritor™ System RSV and Quidel® Sofia® RSV FIA systems for respiratory syncytial virus (RSV) diagnosis

BACKGROUND Respiratory syncytial virus (RSV) is one of the most common causes of severe lower respiratory tract disease among infants and young children. BD Veritor™ System RSV (BD) and Quidel(®) Sofia(®) RSV FIA (QD) are the new generation lateral flow digital immunoassay (DIA) tests with an instrumented read for the qualitative detection of RSV viral antigens. OBJECTIVE To compare the diagnostic accuracies of BD and QD for RSV detection using fresh nasopharyngeal aspirates and nasopharyngeal swab specimens collected in universal transport media during 2013-2014 respiratory season. STUDY DESIGN The two DIA tests were performed simultaneously on randomly selected specimens on a weekly basis during the RSV season until 200 fresh remnant specimens were enrolled. Real-time RT-PCR assay results were used to compare and evaluate the performance of both RSV DIA assays. RESULTS Among 200 specimens tested, RSV real-time RT-PCR assay detected RSV in 104 samples, while QD detected 84 samples and BD detected 74 samples as positive. The overall sensitivity for detection of RSV in comparison to PCR was 71.15% (61.3-79.4) for BD and 80.77% (71.6-87.6) for QD system (P=0.36). The specificity was 100% (95.2-100) for both systems. The work flow analysis revealed that the overall specimen processing time was significantly lower for BD as compared with the QD assay. CONCLUSIONS In comparison with the real-time PCR, the QD system showed a higher sensitivity than that of the BD system, but the difference did not reach statistical significance (P=0.36). Both BD and QD systems were found comparable in terms of specificity.

Viral Etiology of Acute Gastroenteritis in <2-Year-Old US Children in the Post–Rotavirus Vaccine Era

Background The rotavirus disease burden has declined substantially since rotavirus vaccine was introduced in the United States in 2006. The aim of this study was to determine the viral etiology of acute gastroenteritis (AGE) in US children aged <2 years. Methods The New Vaccine Surveillance Network (NVSN) of geographically diverse US sites conducts active pediatric population-based surveillance in hospitals and emergency departments. Stool samples were collected from children aged <2 years with symptoms of AGE (n = 330) and age-matched healthy controls (HCs) (n = 272) between January and December 2012. Samples were tested by real-time reverse-transcriptase polymerase chain reaction assays {adenovirus (type 40 and 41), norovirus, parechovirus A, enterovirus, sapovirus, and astrovirus} and an enzyme immunoassay (rotavirus). All samples that tested positive were genotyped. Results Detection rates of pathogens in children with AGE versus those of HCs were, respectively, 23.0% versus 6.6% for norovirus (P < .01), 23.0% versus 16.0% for adenovirus (P = .08), 11.0% versus 16.0% for parechovirus A (P = .09), 11.0% versus 9.0% for enterovirus (P = .34), 7.0% versus 3.0% for sapovirus (P = .07), 3.0% versus 0.3% for astrovirus (P = .01), and 3.0% versus 0.4% for rotavirus (P = .01). A high prevalence of adenovirus was detected at 1 surveillance site (49.0% for children with AGE and 43.0% for HCs). Norovirus GII.4 New Orleans was the most frequently detected (33.0%) norovirus genotype. Codetection of >1 virus was more common in children with AGE (16.0%) than in HCs (10.0%) (P = .03). Conclusions Norovirus, astrovirus, sapovirus, and rotavirus were detected significantly more in children with AGE than in HCs, and norovirus was the leading AGE-causing pathogen in US children aged <2 years during the year 2012.

Intestinal Carriage of Third-Generation Cephalosporin-Resistant and Extended-Spectrum β-Lactamase-Producing Enterobacteriaceae in Healthy US Children

Background The epidemiology of antibiotic-resistant Enterobacteriaceae intestinal carriage in healthy US children has not been well characterized. Methods Children between 14 days and 14 years of age were enrolled during well-child visits in Oakland, California, Kansas City, Kansas, and Nashville, Tennessee, between December 2013 and March 2015. Data on recent antibiotic use by the child and travel and hospitalization history of all members of each childs household were obtained with a risk-factor survey. Stool specimens collected from the subjects were screened for extended-spectrum β-lactamase-producing (ESBL-P) bacteria using CHROMagar ESBL medium. Putative ESBL-P Escherichia coli and Klebsiella colonies underwent phenotypic confirmation by double-disk synergy testing; confirmed third-generation cephalosporin-resistant (3GCR) isolates underwent additional antibiotic-susceptibility testing. Results In 519 subjects, the overall 3GCR Enterobacteriaceae carriage rate was 4.4% (n = 23) and ranged from 3.4% to 5.1% among the study sites. The ESBL-P Enterobacteriaceae carriage rate was 3.5% (n = 18). The rates of 3GCR Enterobacteriaceae carriage was highest in 1 to <2 year olds at 6.5%, and was 5.2% in <5 year-olds vs 1.7% in ≥5-year-olds (P = .11). 3GCR and ESBL-P Enterobacteriaceae carriage was associated with international travel within the previous year; 11.1% of ESBL-P Enterobacteriaceae carriers reported this history compared with 1.6% of noncarriers (P = .004). No other queried factor was found to increase risk. Of the 24 analyzed 3GCR isolates, 58% were multidrug resistant. Conclusions The 3GCR Enterobacteriaceae carriage rate exceeds 5% in healthy US children <5 years of age. International travel within the previous year increased the risk of 3GCR and ESBL-P Enterobacteriaceae carriage. In contrast, we found no differences in the rates of hospitalization or recent antibiotic exposure between carriers and noncarriers. Young children, who have the highest prevalence of colonization, might be a sentinel population to study to gain a better understanding of community sources of antibiotic-resistant Enterobacteriaceae.

Clinical Predictors of Shigella and Campylobacter Infection in Children in the United States

Abstract Background Infectious gastroenteritis is a major cause of morbidity and mortality among children worldwide. While most episodes are self-limiting, for select pathogens such as Shigella and Campylobacter, etiological diagnosis may allow effective antimicrobial therapy and aid public health interventions. Unfortunately, clinical predictors of such pathogens are not well established and are based on small studies using bacterial culture for identification. Methods We used prospectively collected data from a multi-center study of pediatric gastroenteritis employing multi-pathogen molecular diagnostics to determine clinical predictors associated with 1) Shigella and 2) Shigella or Campylobacter infection. We used machine learning algorithms for clinical predictor identification, then performed logistic regression on features extracted plus pre-selected variables of interest. Results Of 993 children enrolled with acute diarrhea, we detected Shigella spp. in 56 (5.6%) and Campylobacter spp. in 24 (2.4%). Compared with children who had neither pathogen detected (of whom, >70% had ≥1 potential pathogen identified), bloody diarrhea (odds ratio 4.0), headache (OR 2.2), fever (OR 7.1), summer (OR 3.3), and sick contact with GI illness (OR 2.2), were positively associated with Shigella, and out-of-state travel (OR 0.3) and vomiting and/or nausea (OR 0.4) were negatively associated (Table). For Shigella or Campylobacter, predictors were similar but season was no longer significantly associated with infection. Conclusion These results can create prediction models and assist clinicians with identifying patients who would benefit from diagnostic testing and earlier antibiotic treatment. This may curtail unnecessary antibiotic use, and help to direct and target appropriate use of stool diagnostics. Disclosures A. Leber, BioFIre Diagnostics: Research Contractor and Scientific Advisor, Research support, Speaker honorarium and Travel expenses J. Daly, Biofire: Grant Investigator, Grant recipient R. Selvarangan, BioFire Diagnostics: Board Member and Investigator, Consulting fee and Research grant Luminex Diagnostics: Investigator, Research grant J. Dien Bard, BioFire: Consultant and Investigator, Research grant and Speaker honorarium K. Holmberg, BioFire Diagnostics: Employee, Salary K. Bourzac, BioFire Diagnostics: Employee, Salary K. C. Chapin, BioFire Diagnstics: Investigator, Research support A. Pavia, BioFire Diagnostics: Grant Investigator, Research grant