Bacterial Infection In Young Children Research Articles

Neutrophil CD64 Expression as a Diagnostic Marker of Bacterial Infection in Febrile Children Presenting to a Hospital Emergency Department

The expression of CD64 (Fcgamma receptor) is increased in neutrophils from an almost negligible value to a marked level in patients with bacterial infections. CD64 expression on neutrophils might therefore be useful to differentiate between bacterial and viral infections in young children. We evaluated the usefulness of CD64 as a marker for the diagnosis of bacterial infections in children up to the age of 3 years and its ability to differentiate between bacterial and viral infections. Blood samples were drawn from 70 children aged 3 years or younger who presented to the pediatric emergency department with fever as their main complaint. Thirty-eight children were diagnosed as having bacterial infection and 32 as having viral infection. The control group included 39 healthy children. CD64, C-reactive protein (CRP), and procalcitonin levels were determined for each child. The sensitivity and specificity of these parameters were calculated. Neutrophil expression of CD64 was significantly higher in the bacterial infection group compared with the viral infection and the control groups (P < 0.0001). Raising the cutoff for diagnosis of bacterial disease lowered the sensitivity but improved the specificity. CD64 was found to have a very high sensitivity (94.7%), but its specificity was poor (46.5%). No significant differences were found between the diagnostic performance of CD64 and that of CRP: both have high sensitivity and low specificity (94.7% and 47.9%, respectively, for CRP). In contrast, procalcitonin had a betterspecificity (91%), but its sensitivity reached only 71.9%. CD64 expression was increased in patients with respiratory syncytial virus-related infections compared with that in patients with other viral infections and was similar to that found during bacterial illness. Neutrophil CD64 expression is a sensitive marker for diagnosing bacterial infection in young children, but as it is also raised in viral infection, it lacks specificity.

Epidemiologic attributes of invasive non-typhoidal Salmonella infections in Michigan, 1995–2001

To determine: (1) the incidence of invasive salmonellosis, (2) the distribution of specific Salmonella serotypes associated with invasive disease, and (3) the role of demographic characteristics in invasive salmonellosis in Michigan. We conducted a cross-sectional study using laboratory-confirmed cases of salmonellosis reported to the Michigan Department of Community Health between 1995 and 2001. Average annual incidences (AAIs) for invasive salmonellosis were computed, and Poisson regression analysis was used to model the association between demographic attributes and invasive salmonellosis. Of 6797 cases of salmonellosis, 347 (5.1%) were characterized as invasive having an AAI of 0.5/100000. A covariate-adjusted Poisson model showed children aged <1 year to be at higher risk for invasive salmonellosis compared to adults aged 40-49 years (rate ratio (RR) 8.98, 95% confidence interval (CI) 5.69-14.17). No significant differences were found between males and females (RR 1.02, 95% CI 0.83-1.26), African-Americans and Caucasians (RR 0.95, 95% CI 0.64-1.42), and urban and rural residents (RR 0.98, 95% CI 0.76-1.26). Among the most common serotypes associated with invasive salmonellosis (Heidelberg, Typhimurium, and Enteritidis), Salmonella serotype Heidelberg had the highest blood invasiveness ratio (15.79/100). Children aged <1 year, especially of minority groups, are at higher risk for invasive Salmonella infections. Invasive salmonellosis may be included in the differential diagnosis of acute bacterial infections in young children with positive stool cultures for Salmonella.

Structural Requirements for Proinflammatory Activity of Porin P2 Loop 7 from Haemophilus influenzae

Haemophilus influenzae type b (Hib) is one of the leading causes of invasive bacterial infection in young children, characterized by inflammation mainly mediated by cytokines and chemokines. One of the most abundant components of the Hib outer membrane is the P2 porin, which has been shown to induce the release of several inflammatory cytokines. Synthetic peptides corresponding to loops L5, L6, and L7 activate JNK and p38 mitogen-activated protein kinase (MAPK) pathways, L7 being the most active peptide. Therefore, sequence-activity relationships and key residues were identified by elongating sequence to different extents, designing cyclic peptides, and performing an alanine scan of L7. The ability of mutant peptides to induce activation of signal transduction pathways and release of TNF-alpha and IL-6 has been determined, and, in conjunction with CD spectra, bioinformatics analysis, and molecular dynamics data, showed that 6 out of 8 amino acids contribute significantly to the overall activity. Molecular dynamics showed that L7 modifications increased loop rigidity and helicity after Gly6 mutation, thus, providing a possible structural explanation for observed loss of bioactivity. This work provides insights into essential molecular details of P2 that may impact on the pathogenesis of Hib infections where interruption of the signaling cascade could represent an attractive therapeutic strategy.

Acute otitis media in children: a continuing story.

1. Robert M. Siegel, MD* 2. James P. Bien, MD† 1. *Adjunct Associate Professor of Clinical Pediatrics, Cincinnati Children’s Hospital Medical Center, and Cincinnati Pediatric Research Group, Cincinnati, OH 2. †Medical Director, Arnett Clinic, Lafayette, IN, and Cincinnati Pediatric Research Group, Cincinnati, OH After completing this article, readers should be able to: 1. Delineate the most common bacterial infection in young children. 2. Describe the value of antibiotics in acute otitis media. 3. Discuss strategies to reduce unnecessary antibiotic usage. 4. Explain the importance of The Safety-Net Antibiotic Prescription concept. In 1897, L. Emmett Holt published his magnum opus, The Diseases of Infancy and Childhood . He devoted a full chapter to acute otitis, describing much of what we still observe about this condition: its commonality and association with the winter months, the role of eustachian tube dysfunction, and its tendency to recur. He also detailed a very different illness, noting that 43% of cases were associated with measles, scarlet fever, whooping cough, or mumps, and only 29% were associated with “simple catarrh.” Approximately 20% of cases were attributed to teething. Acute otitis infections associated with colds had a benign course and resolution. In contrast, those associated with scarlet fever, diphtheria, or influenza often involved severe invasive complications and resulted in “some degree of impairment of the sense of hearing.” For treatment, he advised blood letting with leeches and the use of dry heat. If these failed to bring relief, he recommended administration of an opiate. Pain and fever lasting into a second day were to be treated with incision of the tympanic membrane. Recurrent and chronic diseases were to be referred to the surgeon. More than 100 years later, acute otitis media (AOM) is the childhood disease diagnosed most commonly, accounting for 20% of pediatric visits. AOM results in more than 24 million office visits, accounts for most outpatient antibiotic prescriptions provided to children, and costs an estimated $5.3 billion annually. Fifty percent of infants in the United States have their first episode before 6 months of age, and 90% experience at least one episode by …

Is a negative dipstick urinalysis good enough to exclude urinary tract infection in paediatric emergency department patients?

Urinary tract infection is a common cause of serious bacterial infection in young children. The non-specific presentation has implications for misdiagnosis and the potential for long-term complications. To determine if a negative dipstick urinalysis is adequate to exclude urinary tract infection in children aged 0-10 years. Data was subdivided into two age groups: 0-2 years and 2-10 years. Retrospective case note review over an 8-month period. Cases included required a printed urinalysis recorded from the Clinitek 50 (Bayer) machine and a printed microscopy and culture result. We defined a negative urinalysis as being negative for all of blood, protein, leucocytes and nitrites. A total of 375 cases were included for statistical calculation. Three hundred and seventy-five cases gave a prevalence of 10.7% with a sensitivity of 92.5%, specificity of 39.4% and a negative predictive value of 97.8%. In the 0-2-year-old group, we demonstrated a prevalence of 15%, a sensitivity of 87.5%, specificity of 39.7% and a negative predictive value of 94.7%. This compares to the older group (2-10 years) with a prevalence of 7.0%, a sensitivity of 100%, specificity of 39.7% and a negative predictive value of 100%. Prevalence of urinary tract infection varied with age with a higher prevalence in the 0-2 years age group. The lower negative predictive value and the higher clinical importance in this age group means that dipstick urinalysis is inadequate to exclude urinary tract infection. Conversely, we believe that children in the 2-10 years age group can adequately have urinary tract infection excluded with a negative dipstick urinalysis.

Predicting serious bacterial infection in young children with fever without apparent source.

The aim of this study was to design a clinical rule to predict the presence of a serious bacterial infection in children with fever without apparent source. Information was collected from the records of children aged 1-36 mo who attended the paediatric emergency department because of fever without source (temperature > or = 38 degrees C and no apparent source found after evaluation by a general practitioner or history by a paediatrician). Serious bacterial infection included bacterial meningitis, sepsis, bacteraemia, pneumonia, urinary tract infection, bacterial gastroenteritis, osteomyelitis and ethmoiditis. Using multivariate logistic regression and the area under the receiver operating characteristic curve (ROC area), the diagnostic value of predictors for serious bacterial infection was judged, resulting in a risk stratification. Twenty-five percent of the 231 patients enrolled in the study (mean age 1.1 y) had a serious bacterial infection. Independent predictors from history and examination included duration of fever, poor micturition, vomiting, age, temperature < 36.7 degrees C or > or = 40 degrees C at examination, chest-wall retractions and poor peripheral circulation (ROC area: 0.75). Independent predictors from laboratory tests were white blood cell count, serum C-reactive protein and the presence of >70 white blood cells in urinalysis (ROC area: 0.83). The risk stratification for serious bacterial infection ranged from 6% to 92%. The probability of a serious bacterial infection in the individual patient with fever without source can be estimated more precisely by using a limited number of symptoms, signs and laboratory tests.

Predicting serious bacterial infection in young children with fever without apparent source

The aim of this study was to design a clinical rule to predict the presence of a serious bacterial infection in children with fever without apparent source. Information was collected from the records of children aged 1‐36 mo who attended the paediatric emergency department because of fever without source (temperature ≥38°C and no apparent source found after evaluation by a general practitioner or history by a paediatrician). Serious bacterial infection included bacterial meningitis, sepsis, bacteraemia, pneumonia, urinary tract infection, bacterial gastroenteritis, osteomyelitis and ethmoiditis. Using multivariate logistic regression and the area under the receiver operating characteristic curve (ROC area), the diagnostic value of predictors for serious bacterial infection was judged, resulting in a risk stratification. Twenty‐five percent of the 231 patients enrolled in the study (mean age 1.1 y) had a serious bacterial infection. Independent predictors from history and examination included duration of fever, poor micturition, vomiting, age, temperature &lt;36.7°C or ≥40°C at examination, chest‐wall retractions and poor peripheral circulation (ROC area: 0.75). Independent predictors from laboratory tests were white blood cell count, serum C‐reactive protein and the presence of ≥70 white blood cells in urinalysis (ROC area: 0.83). The risk stratification for serious bacterial infection ranged from 6% to 92%. Conclusion: The probability of a serious bacterial infection in the individual patient with fever without source can be estimated more precisely by using a limited number of symptoms, signs and laboratory tests.

Otitis media

Otitis media is the most common bacterial infection in young children. The Greater Boston Study 1 showed that, by 1 year of age, >60% of the children had had ≥1 episode of acute otitis media (AOM) and, by 3 years of age, >80% had had AOM and >40% had experienced ≥3 episodes. Acute otitis media is the most common single cause of antimicrobial therapy in children. In many children the effusion stays in the middle ear for weeks or months after the acute infection, thereby necessitating long term follow-up and possibly surgical procedures. It is well-known that otitis media comprises a major health care problem. Several risk factors have been associated with otitis media. Most studies have shown that young age, passive smoking and attendance at day-care centers significantly increase the risk for AOM