Karin L. McGowan

PREVALENCE OF URINARY TRACT INFECTION IN FEBRILE YOUNG CHILDREN IN THE EMERGENCY DEPARTMENT

Objective. Establish prevalence rates of urinary tract infection (UTI) in febrile infants and young girls in an emergency department (ED) by demographics and clinical parameters. Methods. Cross-sectional prevalence survey of 2411 (83%) of all infants younger than 12 months and girls younger than 2 years of age presenting to the ED with a fever (≥38.5°C) who did not have a definite source for their fever and who were not on antibiotics or immunosuppressed. Otitis media, gastroenteritis, and upper respiratory infection were considered potential but not definite sources of fever. Results. Overall prevalence of UTI (growth of ≥104 CFU/mL of a urinary tract pathogen) was 3.3% (95% confidence interval [CI]: 2.6,4.0). Higher prevalences occurred in whites (10.7%; 95% CI: 7.1,14.3), girls (4.3%; 95% CI: 3.3,5.3), uncircumcised boys (8.0%; 95% CI: 1.9,14.1), and those who did not have another potential source for their fever (5.9%; 95% CI: 3.8,8.0), had a history of UTI (9.3%; 95% CI: 3.0,20.3), malodorous urine or hematuria (8.6%; 95% CI: 2.8,19.0), appeared “ill” (5.7%; 95% CI: 4.0,7.4), had abdominal or suprapubic tenderness on examination (13.2%; 95% CI: 3.7,30.7), or had fever ≥39°C (3.9%; 95% CI: 3.0,4.8). White girls had a 16.1% (95% CI: 10.6,21.6) prevalence of UTI. Conclusions. UTI is prevalent in young children, particularly white girls, without a definite source of fever. Specific clinical signs and symptoms of UTI are uncommon, and the presence of another potential source of fever such as upper respiratory infection or otitis media is not reliable in excluding UTI.

Risk Factors for and Outcomes of Bloodstream Infection Caused by Extended-Spectrum β-Lactamase–Producing Escherichia coli and Klebsiella Species in Children

Objective. The increasing prevalence of infections caused by extended-spectrum β-lactamase–producing Escherichia coli and Klebsiella species (ESBL-EK) has become a growing concern in the hospitalized patient population. Previous studies on risk factors for infection with ESBL-EK have mainly focused on adult populations, and these findings may not be relevant among the pediatric population that experiences a unique set of health care exposures and underlying conditions. The objective of this study was to define the risk factors and outcomes associated with ESBL-EK bloodstream infections in children. Methods. We conducted a nested case-control study using data from the Childrens Hospital of Philadelphia from May 1, 1999, to September 30, 2003. Eligible patients were identified from the hospital database of microbiology laboratory records. All patients with ESBL-EK bloodstream infections were compared to a random sample of patients with non–ESBL-EK bloodstream infections. Risk factors analyzed included prior antimicrobial use, comorbid conditions, and demographic characteristics. Pulsed-field gel electrophoresis was performed to determine genetic relatedness of the ESBL-EK isolates. Results. Thirty-five cases and 105 control subjects were included in the study. The median age among the cases was 2 years (interquartile range: 0–11), compared with 1 year (interquartile range: 0–8) among control subjects. Patients with ESBL-EK infections were 5.8 times (95% confidence interval: 1.9–17.7) more likely to have had exposure to an extended-spectrum cephalosporin in the 30 days before infection than those with non–ESBL-EK infections. Other independent predictors of ESBL-EK infection were being female, infection with a Klebsiella species, and steroid use in the 30 days before infection. All ESBL-EK isolates were susceptible to carbapenem antibiotics. Pulsed-field gel electrophoresis analysis revealed that the ESBL-EK isolates were polyclonal. Although a substantially higher proportion of children with ESBL-EK died (in-hospital mortality: 36% vs 13%), this difference was not statistically significant. Conclusions. Receipt of extended-spectrum cephalosporins in the 30 days before infection by an Escherichia coli or Klebsiella species is significantly associated with having an ESBL-EK infection in hospitalized children. Curtailed use of cephalosporins among high-risk groups may reduce the occurrence of ESBL-EK infections. Future studies on identifying high-risk children and investigating the impact of curtailed third-generation cephalosporin use to limit additional emergence of ESBL-EK infections should be undertaken.

Emergence of Vaccine-Related Pneumococcal Serotypes as a Cause of Bacteremia

BACKGROUND The heptavalent pneumococcal conjugate vaccine (PCV7) has decreased the incidence of invasive pneumococcal disease among children in the United States. In the postlicensure period, the impact of non-PCV7 serotypes against pediatric pneumococcal bacteremia is unknown. METHODS Episodes of bacteremia due to Streptococcus pneumoniae and other respiratory pathogens (ORP), namely Neisseria meningitidis, Haemophilus influenzae, and Moraxella catarrhalis, were identified in children <18 years old at the Childrens Hospital of Philadelphia from January 1999 to May 2005. For pneumococci, serotype distribution and antibiotic resistance were compared. RESULTS A total of 188 episodes of pneumococcal bacteremia and 55 episodes of ORP bacteremia were identified. By comparing data from 1999-2000 with data from 2001 to May 2005, we found that the incidence of pneumococcal bacteremia decreased by 57%. The incidence of bacteremia caused by ORPs was unchanged; 1.43 episodes (95% confidence interval [CI], 0.84-2.29 episodes) to 1.25 (95% CI, 0.88-1.71) per 10,000 emergency department visits. Vaccine serotypes caused 85% of episodes of bacteremia in 1999-2000, compared with 34% of episodes of bacteremia in 2001 to May 2005 (P<.01). The percentage of isolates nonsusceptible to penicillin increased from 25% to 39% (P<.05). The percentage of episodes of pneumococcal bacteremia caused by vaccine-related serotypes--those of the same serogroup but not of the same serotype as PCV7--increased from 6% of episodes in the prelicensure period to 35% of episodes in the postlicensure period (P<.01). Rates of serotype pneumococcal bacteremia caused by nonvaccine serotypes were not statistically different between the 2 periods. CONCLUSIONS The overall incidence of pneumococcal bacteremia decreased by 57% after the introduction of PCV7. During the postlicensure period, there were significant decreases in the incidence of pneumococcal bacteremia caused by vaccine serotypes; however, rates of penicillin resistance and bacteremia due to vaccine-related serotypes increased.

Comparison of the Idaho Technology FilmArray system to real-time PCR for detection of respiratory pathogens in children.

ABSTRACT The FilmArray Respiratory Panel (RP) multiplexed nucleic acid amplification test (Idaho Technology, Inc., Salt Lake City, UT) was compared to laboratory-developed real-time PCR assays for the detection of various respiratory viruses and certain bacterial pathogens. A total of 215 frozen archived pediatric respiratory specimens previously characterized as either negative or positive for one or more pathogens by real-time PCR were examined using the FilmArray RP system. Overall agreement between the FilmArray RP and corresponding real-time PCR assays for shared analytes was 98.6% (kappa = 0.92 [95% confidence interval (CI), 0.89 to 0.94]). The combined positive percent agreement was 89.4% (95% CI, 85.4 to 92.6); the negative percent agreement was 99.6% (95% CI, 99.2 to 99.8). The mean real-time PCR threshold cycle (CT ) value for specimens with discordant results was 36.46 ± 4.54. Detection of coinfections and correct identification of influenza A virus subtypes were comparable to those of real-time PCR when using the FilmArray RP. The greatest comparative difference in sensitivity was observed for adenovirus; only 11 of 24 (45.8%; 95% CI, 27.9 to 64.9) clinical specimens positive for adenovirus by real-time PCR were also positive by the FilmArray RP. In addition, upon testing 20 characterized adenovirus serotypes prepared at high and low viral loads, the FilmArray RP did not detect serotypes 6 and 41 at either level and failed to detect serotypes 2, 20, 35, and 37 when viral loads were low. The FilmArray RP system is rapid and extremely user-friendly, with results available in just over 1 h with almost no labor involved. Its low throughput is a significant drawback for laboratories receiving large numbers of specimens, as only a single sample can be processed at a time with one instrument.

Surface colonization with coagulase-negative staphylococci in premature neonates

To follow the emergence of surface colonization with coagulase-negative staphylococci in neonates, we sampled four surface sites (axilla, ear, nasopharynx, and rectum) in 18 premature infants during the first 4 weeks of life. Swabs were obtained on the first day of life, twice weekly for 2 weeks, and weekly thereafter. Isolates were characterized by species, biotype, antibiotic susceptibility patterns, and slime production. Over 4 weeks the percentage of infants with Staphylococcus epidermidis as the only surface coagulase-negative staphylococci rose from 11% to 100%. Predominance of a single S. epidermidis biotype increased from none to 89%. Multiple antibiotic resistance rose from 32% to 82% of isolates, and the prevalence of slime production increased from 68% to 95%. This microbiologic pattern was established by the end of the first week of life and persisted throughout the month of study. In three infants, S. epidermidis sepsis developed with organisms identical to their predominant surface isolate. We conclude that species, multiple antibiotic resistance, and slime production appear to confer a selective advantage for the surface colonization of premature newborn infants in the intensive care nursery environment. Infants so colonized may be at greater risk for subsequent infection with these strains of coagulase-negative staphylococci.

Clinical and molecular epidemiology of community-acquired methicillin-resistant Staphylococcus aureus infections among children with risk factors for health care-associated infection: 2001-2003.

Background: Methicillin-resistant Staphylococcus aureus (MRSA) has recently emerged as a common cause of infection in children in many parts of the world. The epidemiology of community-acquired MRSA (CA-MRSA) among healthy children has been recently described. However, little is known about CA-MRSA in children with underlying medical conditions. Objective: To compare the clinical and molecular epidemiology of CA-MRSA in children with and without risk factors for health care-associated infections (RF-HAI). Methods: We conducted a 3-year retrospective cohort study of children with CA-MRSA infection. RF-HAI, including hospitalization within the past year, indwelling medical devices or chronic medical condition, were identified by chart review. Genetic relatedness of CA-MRSA strains was assessed by pulsed field gel electrophoresis. Polymerase chain reaction was used to detect Panton-Valentine leukocidin and determine staphylococcal chromosomal cassette carrying the mecA methicillin-resistant gene (SCCmec) type. Results: We identified 446 episodes of community-acquired S. aureus infections, of which 134 (30%) were caused by MRSA. During the 3-year study period, the proportion of S. aureus infections caused by MRSA rose from 15% (12 of 80) to 40% (93 of 235) (P < 0.001) with the increase noted predominately in children with skin and soft tissue infections. RF-HAI were identified in 56 (42%) patients with CA-MRSA. Among subjects with CA-MRSA, children with RF-HAI were more likely to have had an invasive infection than healthy children (32% versus 5%; P < 0.001). CA-MRSA isolates from children with RF-HAI were similar to those without RF-HAI; all laboratory-retained CA-MRSA isolates harbored the SCCmec type IV cassette, and almost all isolates were susceptible to trimethoprim-sulfamethoxazole and clindamycin. However, pulsed field gel electrophoresis revealed greater molecular diversity among CA-MRSA isolates recovered from children with RF-HAI compared with those from otherwise healthy children (P = 0.001). Additionally CA-MRSA isolates from children with RF-HAI were less likely to contain sequences for Panton-Valentine leukocidin (P < 0.001) and more likely to be resistant to 3 or more classes of antibiotics (P = 0.033). Conclusion: CA-MRSA strains recovered from children with RF-HAI were phenotypically similar to those recovered from healthy children The absence of SCCmec type II or III MRSA among children with RF-HAI suggests that CA-MRSA strains might have become endemic within pediatric health care facilities.

Assessment of the test characteristics of C-reactive protein for septic arthritis in children.

The purpose of this study was to determine the test characteristics of C-reactive protein (CRP) in the diagnosis of septic arthritis in children and to compare with erythrocyte sedimentation rate (ESR). The authors reviewed patients with synovial fluid aspiration sent for culture and Gram stain for whom a CRP was drawn within 24 hours of presentation. Descriptive statistics and univariate analyses were performed. Results for CRP were compared with ESR. Thirty-nine of 133 patients had septic arthritis. Sensitivity of CRP ranged from 41% to 90%, specificity from 29% to 85%. Positive predictive values ranged from 34% to 53%, negative predictive values from 78% to 87%. In comparison to ESR, CRP is a better independent predictor of disease. CRP is a better negative predictor than a positive predictor of disease. Indeed, if the CRP is <1.0 mg/dL, the probability that the patient does not have septic arthritis is 87%.

Recurrence rate of clostridium difficile infection in hospitalized pediatric patients with inflammatory bowel disease

Background: The incidence and associated morbidity of Clostridium difficile (CD) infection has been increasing at an alarming rate in North America. Clostridium difficile‐associated diarrhea (CDAD) is the leading cause of nosocomial diarrhea in the USA. Patients with CDAD have longer average hospital admissions and additional hospital costs. Evidence has demonstrated that patients with inflammatory bowel disease (IBD) have a higher incidence of CD in comparison to the general population. The aim of this study was to compare the rate of recurrence of CD in hospitalized pediatric patients with IBD compared to hospitalized controls. The secondary aim was to evaluate whether infection with CD resulted in a more severe disease course of IBD. Methods: This was a nested case control retrospective study of hospitalized pediatric patients. Diagnosis of CD was confirmed with stool Toxin A and B analysis. The following data were obtained from the medical records: demographic information, classification of IBD including location of disease, IBD therapy, and prior surgeries. In addition, prior hospital admissions within 1 year and antibiotic exposure were recorded. The same information was recorded following CD infection. Cases were patients with IBD and CD; two control populations were also studied: patients with CD but without IBD, and patients with IBD but without CD. Results: For aim 1, a total of 111 eligible patients with IBD and CD infection and 77 eligible control patients with CD infection were included. The rate of recurrence of CD in the IBD population was 34% compared to 7.5% in the control population (P < 0.0001). In evaluating the effect of CD infection on IBD disease severity, we compared the 111 IBD patients with CD to a second control population of 127 IBD patients without CD. 57% of IBD‐CD patients were readmitted with an exacerbation of disease within 6 months of infection with CD and 67% required escalation of therapy following CD infection, compared to 30% of IBD patients without CD (P < 0.001). Of the patients with IBD and CD, 44% of the cases were new‐onset IBD, 63% were on immunosuppression therapy, and 33% were on gastric acid suppression prior to infection. In comparing the IBD‐CD and control CD populations, there was no significant difference in antibiotic exposure: 33% of IBD patients and 26% of control patients were on antibiotics (P < 0.2). With regard to prior hospitalization, 10% of patients with IBD were hospitalized in the 30 days prior to infection in comparison to 27% of the control CD patients (P < 0.002). Conclusions: CD infection in patients with IBD results in a higher rate of recurrence and is associated with higher morbidity than the general population. Patients with IBD often required hospitalization and escalation of therapy following infection with CD, suggesting that CD resulted in increased severity of IBD disease. In addition, IBD patients were more likely develop community‐acquired CD, while the control patients developed nosocomial infections, indicating a higher susceptibility to CD infection in patients with IBD. (Inflamm Bowel Dis 2011;)

Outpatient Pediatric Blood Cultures: Time to Positivity

Objective. Using a continuously monitoring blood culture system, we determined the time to positivity of blood cultures performed on immunocompetent infants and children who were not receiving antibiotics at the time of culture. Study Design. This study was conducted prospectively using blood cultures taken in the emergency department and outpatient clinics of an urban pediatric teaching hospital from February 1, 1993, through December 31, 1996. Cultures were excluded if obtained from patients receiving antibiotics, patients with a central line, patients with prosthetic devices, or those being followed by the oncology division. Our measures included: 1) recording the time to positive culture obtained by using a continuously monitoring blood culture instrument, 2) patient information derived from the hospital computer system concerning antibiotic use and the presence of indwelling central venous catheters and prosthetic devices, and 3) a chart review of 10% of patients from whom positive cultures were obtained. Results. During the 47-month study period, 10 200 single bottle blood cultures were obtained, 711 (6.97%) of which became positive. Patients ranged in age from <1 week to 24 years (mean: 2.00 years). Two hundred fifty-eight cultures (36.3%) contained only pathogens, 370 (52%) contained only skin contaminants, and 83 (11.7%) contained a mixture of contaminant and pathogen. Of the 258 cultures containing only pathogens, 14% were positive by 12 hours, 87% by 24 hours, 92% by 36 hours, 95% by 48 hours, 98% by 60 hours, and 99.7% by 72 hours. Ninety-five percent of critical pediatric pathogens including Streptococcus pneumoniae,Salmonella and other Enterobacteriaceae,Neisseria meningitidis, and groups A and B streptococci were detected in <24 hours. Conclusion. Because 87% of all cultures containing pathogens were detected within the first 24 hours of incubation, this study can assist emergency department, clinic, and primary care clinicians when making critical decisions concerning patients on whom blood cultures were obtained. Data on time to positivity of blood cultures can be used in conjunction with clinical status to support clinicians in making patient management decisions. Use of short stay (≤24 hours) or extended care units requiring less patient supervision may be easier to justify when a continuously monitoring blood culture instrument is used in the microbiology laboratory.bacteremia, sepsis.

Clinical evaluation of a rapid screening test for urinary tract infections in children

Ka thy N. Shaw, MD, D a v i d Hexter , MD,* Karin L. M c G o w a n , PhD, a n d J. San fo rd Schwar t z , MD From the Emergency Department, General Pediatrics Division, and the Department of Microbiology, Childrens Hospital of Philadelphia; the Departments of Pediatrics and Pathology, University of Pennsylvania School of Medicine, Philadelphia; and the Department of Health Care Systems, Wharton School and Leonard Davis Institute of Health Economics, and the Department of Medicine, University of Pennsylvania, Philadelphia