Development and validation of a multiplex real-time PCR assay for detection and quantification of Streptococcus pneumoniae in pediatric respiratory samples.

IMPORTANCE: Streptococcus pneumoniae (Spn) is the world's leading cause of lower respiratory tract infection morbidity and mortality in children. However, current clinical microbiological methods have disadvantages. Spn can be difficult to grow in laboratory conditions if a patient is pre-treated, and Spn antigen testing has unclear clinical utility in children. Syndromic panel testing is less cost-effective than targeted PCR if clinical suspicion is high for a single pathogen. Also, such testing entails a full, expensive validation for each panel target if used for multiple respiratory sources. Therefore, better diagnostic modalities are needed. Our study validates a multiplex PCR assay with three genomic targets for semi-quantitative and quantitative Spn molecular detection from lower respiratory sources for clinical testing and from upper respiratory sources for research investigation.

Two Blood Cultures With Age-Appropriate Volume Enhance Suspected Sepsis Decision-Making.

BACKGROUND: Multiple blood cultures have been shown to improve pathogen yield and antimicrobial stewardship for adult patients with suspected serious bacterial infection (SBI). For children, the use of multiple blood cultures is less common and volume recommendations are more complicated, often resulting in single cultures with low volume. METHODS: In 2010, Children's Hospital Colorado instituted electronic medical record (EMR) decision support to recommend collection of 2 blood cultures before administration of antibiotics for suspected SBI. Recommended blood culture volumes were calculated by age rather than weight. We evaluated all children admitted to inpatient units between 2008 and 2009 (pre-intervention) and 2011 and 2013 (postintervention) who received antibiotics in the hospital after having blood cultures drawn in the emergency department, excluding those with a length of stay >8 days. We compared blood culture yield, isolate classification (pathogen vs contaminant), and antimicrobial modifications before and after the interventions. RESULTS: A total of 3948 children were included in the study. EMR guidelines were associated with a significantly higher number of children with multiple blood cultures drawn before antibiotic administration (88.0% vs 12.3%; P < .001) and an increased percentage of blood cultures with the recommended volume (74.3% vs 15.2%; P < .001), resulting in a significantly higher pathogen isolation rate and improved antimicrobial decisions. Multiple cultures helped define the role of common contaminants in the clinical decision process. CONCLUSIONS: Multiple blood cultures with age-based volumes taken before starting antibiotics increase pathogen isolation rates and appropriate modification of antimicrobial treatment in children.

Rapid identification of nonblood sterile site broth cultures using the FilmArray blood culture identification panel.

The FilmArray Blood Culture Identification Panel was validated for nonblood sterile site specimens with clinical impact of rapid identification compared to conventional diagnostics. The panel accurately identified target organisms from 98% of positive broth cultures a median 1.1 day faster than conventional techniques (P < 0.0001) with potential clinical impact in 22% of cases.

Clinical Impact and Provider Acceptability of Real-Time Antimicrobial Stewardship Decision Support for Rapid Diagnostics in Children With Positive Blood Culture Results.

BACKGROUND: Rapid diagnostic technologies for infectious diseases have the potential to improve clinical outcomes, but guideline-recommended antimicrobial stewardship (AS) strategies are not currently optimized for rapid intervention. We evaluated the clinical impact and provider acceptability of implementing real-time AS decision support for children with positive blood culture results according to the FilmArray blood culture identification panel (BCID [BioFire Diagnostics]) at Children's Hospital Colorado. METHODS: A pre-post quasi-experimental design was used to compare the outcomes of 100 postintervention children with positive blood culture results matched with 200 preintervention control children. Causative organisms in the preintervention group were identified using conventional microbiologic techniques and communicated to providers by a microbiology technologist. Postintervention organisms were identified by the BCID and communicated by an AS provider in real time with interpretation and antimicrobial recommendations. The primary outcome was time to optimal antimicrobial therapy (time from blood culture collection to start of predetermined pathogen-specific regimen or antimicrobial discontinuation for contaminants) compared by a log-rank test and Kaplan-Meier analysis. Provider acceptability of the intervention was assessed via E-mailed surveys. RESULTS: The median time to optimal therapy decreased from 60.2 hours before intervention to 26.7 hours after intervention (P = .001). Among children with blood cultures that contained true pathogens, the time to effective antimicrobial therapy decreased from 6.9 to 3.4 hours (P = .03). Unnecessary antibiotic initiation for children with a culture that contained organisms considered to be contaminants decreased from 76% to 26% (P < .001). Providers reported a change in management as a result of BCID results in 73% of the cases and a mean overall satisfaction rating of 4.8 on a 5-point Likert scale. CONCLUSIONS: Real-time AS decision support for rapid diagnostics is associated with improved antimicrobial use and high satisfaction ratings by providers.

Comparison of Whole-Genome Sequencing and Molecular-Epidemiological Techniques for Clostridium difficile Strain Typing.

We analyzed in parallel 27 pediatric Clostridium difficile isolates by repetitive sequence-based polymerase chain reaction (RepPCR), pulsed-field gel electrophoresis (PFGE), and whole-genome next-generation sequencing. Next-generation sequencing distinguished 3 groups of isolates that were indistinguishable by RepPCR and 1 isolate that clustered in the same PFGE group as other isolates.

Investigation of a cluster of Clostridium difficile infections in a pediatric oncology setting.

BACKGROUND: We investigated an increase in Clostridium difficile infection (CDI) among pediatric oncology patients. METHODS: CDI cases were defined as first C difficile positive stool tests between December 1, 2010, and September 6, 2012, in pediatric oncology patients receiving inpatient or outpatient care at a single hospital. A case-control study was performed to identify CDI risk factors, infection prevention and antimicrobial prescribing practices were assessed, and environmental sampling was conducted. Available isolates were strain-typed by pulsed-field gel electrophoresis. RESULTS: An increase in hospital-onset CDI cases was observed from June-August 2012. Independent risk factors for CDI included hospitalization in the bone marrow transplant ward and exposure to computerized tomography scanning or cefepime in the prior 12 weeks. Cefepime use increased beginning in late 2011, reflecting a practice change for patients with neutropenic fever. There were 13 distinct strain types among 22 available isolates. Hospital-onset CDI rates decreased to near-baseline levels with enhanced infection prevention measures, including environmental cleaning and prolonged contact isolation. CONCLUSION: C difficile strain diversity associated with a cluster of CDI among pediatric oncology patients suggests a need for greater understanding of modes and sources of transmission and strategies to reduce patient susceptibility to CDI. Further research is needed on the risk of CDI with cefepime and its use as primary empirical treatment for neutropenic fever.

High colonization rate and prolonged shedding of Clostridium difficile in pediatric oncology patients.

Surveillance testing for Clostridium difficile among pediatric oncology patients identified stool colonization in 29% of patients without gastrointestinal symptoms and in 55% of patients with prior C. difficile infection (CDI). A high prevalence of C. difficile colonization and diarrhea complicates the diagnosis of CDI in this population.

Association of Bacillus cereus infection with contaminated alcohol prep pads.

BACKGROUND: Bacillus species have caused healthcare-associated outbreaks of invasive disease as well as pseudo-outbreaks. We report an outbreak investigation of blood cultures positive for Bacillus cereus associated with alcohol prep pads (APPs) contaminated with B. cereus and Bacillus species resulting in a rapid internal product recall and subsequent international product recall. DESIGN: Epidemiologic and microbiologic outbreak investigation. SETTING: A 300-bed tertiary care children's hospital in Aurora, Colorado. PATIENTS: Patients with blood or cerebrospinal fluid cultures positive for B. cereus. METHODS: Three patients with blood cultures positive for B. cereus were identified in late 2010. Breaches in procedural and surgical techniques, common interventions, and products were explored. The following 3 common products were cultured: sterile saline syringes, chlorhexidine/alcohol skin preparation solution, and APPs. Repetitive sequence-based polymerase chain reaction (Rep-PCR) was used to compare isolates obtained from patients and from APPs and was confirmed by independent pulsed-field gel electrophoresis. RESULTS: There appeared to be a significant increase in blood cultures positive for B. cereus during 2009-2010. B. cereus and other Bacillus species were cultured from the internal contents of 63.3% of APPs not labeled as sterile, and 8 of the 10 positive lots were manufactured after 2007. None of the isolates obtained from the patients matched strains isolated from the APPs. However, some lots of APPs had strains that were indistinguishable from one another. CONCLUSIONS: APPs that were not labeled as sterile were contaminated with Bacillus species. The product was immediately recalled internally and replaced with APPs from another manufacturer that were labeled as sterile. On January 3, 2011, the manufacturer voluntarily recalled its APPs. Healthcare facilities, healthcare providers, and users of APPs should avoid the use of APPs not specifically labeled as sterile.

An outbreak of Burkholderia cepacia complex associated with intrinsically contaminated nasal spray.

OBJECTIVE: To determine the source of Burkholderia cepacia complex associated with a hospital outbreak and describe the measures taken to identify and confirm the source. SETTING: A 250-bed, tertiary care pediatric hospital in Denver, Colorado. METHODS: An epidemiologic investigation was used to identify possible causes for an apparent outbreak of B. cepacia complex in pediatric patients who had new positive cultures with this organism from December 2003 to February 2004. Chart review, microbiology reports, surgical records, site visits, literature review, staff interviews, and cultures of common products and equipment were performed to determine a source of contamination. Random amplified polymorphic DNA and pulsed-field gel electrophoresis typing, performed by 2 independent laboratories, were used for molecular typing of patient and source isolates. RESULTS: Five pediatric patients had new positive B. cepacia complex cultures from either the sinus or the respiratory tract, and all 5 patients had prior exposure to 0.05% oxymetazoline hydrochloride Major Twice-A-Day 12-hour nasal spray (Proforma, Miami, FL). Four of the 5 patients had isolates that were identical to the B. cepacia complex isolates recovered from the unopened Twice-A-Day 12-hour nasal spray. CONCLUSIONS: Intrinsic contamination of Major Twice-A-Day 12-hour nasal spray with B. cepacia complex resulted in nosocomial transmission to 4 patients at our facility and resulted in a voluntary product recall by the manufacturer. B. cepacia complex species are common contaminants of an increasing variety of nonsterile medical products. Enhanced culture techniques may be useful in evaluating possible product contamination, suggesting additional measures that should be considered to assure the safety of products that may be used in high-risk patients.

Lactobacillus rhamnosus GG bacteremia associated with probiotic use in a child with short gut syndrome.

Probiotic agents are increasingly used for the treatment and prevention of a variety of infectious and inflammatory conditions. They are generally safe, but complications of probiotic use can occur. In this report, we describe bacteremia after ingestion of a Lactobacillus rhamnosus GG probiotic tablet in a child with short gut syndrome. We used sequencing of the ribosomal operon region and strain typing with pulsed field electrophoresis of the isolates to show identity between the tablet and bloodstream isolates.

Effect of 24-hour intravenous tubing set change on the sterility of repackaged fat emulsion in neonates.

BACKGROUND: Duration of intravenous fat emulsion (IVFE) infusions, precise method of administration (manufactured bottle vs repackaged syringe), and interval for administration set change continue to be debated. OBJECTIVE: To determine the contamination rate associated with replacing IVFE administration sets every 24 hours in newborn infants receiving fat emulsion repackaged into unit-of-use syringes. METHODS: This was a prospective, microbiologic study of 90 administration sets used in 19 neonates. IVFE samples were obtained from administration sets at the end of a 19- to 23-hour infusion and prior to daily tubing set change from infants who received repackaged IVFE. Samples of IVFE (1-3 mL) were aseptically removed at the catheter connection site proximal to the patient, transferred into BACTEC PEDSPlus culture media, and continuously monitored for 5 days to detect gram-positive and gram-negative organisms, as well as yeast. RESULTS: Two samples (2.27%) grew coagulase-negative Staphylococcus. Both samples were from the same asymptomatic patient and were obtained on consecutive days. A blood sample obtained through this infant's central catheter grew the same organism and suggested catheter hub colonization as the primary site of microbe origin. CONCLUSIONS: Microbial contamination of IVFE infusion sets changed at 24-hour intervals, using unit-of-use syringes in neonates, was low at 2.2%.