Etiology of community-acquired pneumonia in 254 hospitalized children

Estudio clínico y epidemiológico de la neumonía adquirida en la comunidad en niños menores de 5 años de edad

OBJECTIVE

To describe the clinical characteristics of community-acquired pneumonia and associated morbidity in children under 5 years old.

PATIENTS AND METHOD

We performed a prospective epidemiological study in 12 primary care clinics and two pediatric emergency departments in Vizcaya, Spain. Demographic, clinical, radiological, laboratory and treatment data were recorded at diagnosis. Different pneumonia groups were established on the basis of radiological images (lobar pattern), total leucocyte count (> 15,000/ml) and C-reactive protein value (> 80 mg/l). These groups ranged from definitive pneumococcal pneumonia (pneumococcus isolated in usually sterile specimens) to pneumonia of probable non-pneumococcal etiology. All patients were followed-up for 7 to 15 days after diagnosis to ascertain outcome.

RESULTS

Between February and April 2003, 412 children with pneumonia were enrolled. The mean age was 33.4 6 15.34 months and 21 % of the patients had received the pneumococcal conjugate vaccine. Overall 20 % had general malaise and 14.6 % required admission, with a mean length of hospital stay of 4.10 +/- 2.21 days. The mean length of treatment was 9.51 +/- 2.44 days and the mean number of visits to the primary care pediatrician was 2.02 6 1.10. Fifty-three patients (12.9 %) had definitive or highly probable pneumococcal pneumonia and these children had higher temperature (38.74 +/- 0.84 vs 38.38 +/- 0.94 degrees C), a higher percentage of general malaise (50.9 % vs 15.3 %) and a higher hospitalization rate (41.5 % vs 10.5 %).

CONCLUSIONS

Community-acquired pneumonia in children under 5 years old provokes high morbidity. According to clinical, radiological and laboratory data, suspected pneumococcal pneumonia seems more severe than forms probably caused by other agents.

The burden of pneumonia in children in the developed world

There are few comprehensive epidemiological studies of pneumonia in the developed world. Ascertainment and definition are important variables in the estimation of pneumonia incidence both in primary care and from hospital data. The available figures suggest a burden of disease in the order of 10-15 cases/1000 children per year and a hospital admission rate of 1-4/1000 per year. Both incidence and hospital admission are greatest in the youngest children and rapidly fall after the age of 5 years. In a majority of cases of community acquired pneumonia an organism is not identified. Viral infections are common and influenza A, B, respiratory syncitial virus (RSV) and parainfluenza 1, 2 and 3 are the most common viruses identified. Streptococcus pneumoniae is the most common bacterial cause. Broad brush calculations suggest that the NHS cost of childhood pneumonia in England is 6-8 million pound sterling per annum. This does not include family and social costs. There is potential for new vaccine strategies to decrease childhood pneumonia.

Incidence of respiratory viruses in preterm infants submitted to mechanical ventilation

The objectives of this study were to determine the incidence of infection by respiratory viruses in preterm infants submitted to mechanical ventilation, and to evaluate the clinical, laboratory and radiological patterns of viral infections among hospitalized infants in the neonatal intensive care unit (NICU) with any kind of acute respiratory failure. Seventy-eight preterm infants were studied from November 2000 to September 2002. The newborns were classified into two groups: with viral infection (Group I) and without viral infection (Group II). Respiratory viruses were diagnosed in 23 preterm infants (29.5%); the most frequent was respiratory syncytial virus (RSV) (14.1%), followed by influenza A virus (10.2%). Rhinorrhea, wheezing, vomiting and diarrhea, pneumonia, atelectasis, and interstitial infiltrate were significantly more frequent in newborns with nosocomial viral infection. There was a correlation between nosocomial viral infection and low values of C-reactive protein. Two patients with mixed infection from Group I died during the hospital stay. In conclusion, RSV was the most frequent virus in these patients. It was observed that, although the majority of viral lower respiratory tract infections had a favorable course, some patients presented a serious and prolonged clinical manifestation, especially when there was concomitant bacterial or fungal infection.

The novel parainfluenza virus hemagglutinin-neuraminidase inhibitor BCX 2798 prevents lethal synergism between a paramyxovirus and Streptococcus pneumoniae

An association exists between respiratory viruses and bacterial infections. Prevention or treatment of the preceding viral infection is a logical goal for reducing this important cause of morbidity and mortality. The ability of the novel, selective parainfluenza virus hemagglutinin-neuraminidase inhibitor BCX 2798 to prevent the synergism between a paramyxovirus and Streptococcus pneumoniae was examined in this study. A model of secondary bacterial pneumonia after infection with a recombinant Sendai virus whose hemagglutinin-neuraminidase gene was replaced with that of human parainfluenza virus type 1 [rSV(hHN)] was established in mice. Challenge of mice with a sublethal dose of S. pneumoniae 7 days after a sublethal infection with rSV(hHN) (synergistic group) caused 100% mortality. Bacterial infection preceding viral infection had no effect on survival. The mean bacterial titers in the synergistic group were significantly higher than in mice infected with bacteria only. The virus titers were similar in mice infected with rSV(hHN) alone and in dually infected mice. Intranasal administration of BCX 2798 at 10 mg/kg per day to the synergistic group of mice starting 4 h before virus infection protected 80% of animals from death. This effect was accompanied by a significant reduction in lung viral and bacterial titers. Treatment of mice 24 h after the rSV(hHN) infection showed no protection against synergistic lethality. Together, our results indicate that parainfluenza viruses can prime for secondary bacterial infections. Prophylaxis of parainfluenza virus infections with antivirals might be an effective strategy for prevention of secondary bacterial complications in humans.

Short-Course Therapy for Community-Acquired Pneumonia in Paediatric Patients

Studies conducted over the past few years for the treatment of pneumonia have provided data on the basis of which therapeutic decisions concerning the duration of therapy can be taken. Results from a majority of the studies conducted in hospitalised patients using the conventional methods for diagnosing pneumonia have methodological problems, which make it difficult to draw definite conclusions. Despite these limitations, the overall trend of these descriptive studies show a therapy of < or =5 days being as effective as the longer course of 7-14 days for children up to the age of 12 years. Data for duration of antibacterial therapy for infants <2 months of age hardly exists. Evidence suggests that a shorter course of antibacterial therapy of 3 days is effective for treatment of community-acquired, non-severe ambulatory pneumonia in immunocompetent children aged 2-59 months old. Shorter duration of therapy offers several potential advantages that include prevention of the emergence of antimicrobial resistance, lower healthcare costs, improved adherence to therapy and fewer adverse effects. There is a need to improve the evidence base for the optimum duration of therapy for children hospitalised with severe pneumonia.

New considerations in the treatment and prevention of rhinovirus infections

Rhinoviruses are a very common cause of infections in children. Although these infections are most closely associated with the common cold, recent studies have established the rhinoviruses as important causes of other upper and lower respiratory illnesses as well. Treatment of these infections is limited to symptomatic therapy. There is no clear evidence that treatment with zinc or echinacea have any role in these infections. Interruption of transmission by handwashing remains the only method for prevention of rhinovirus infections.

Performance of the Binax NOW Streptococcus pneumoniae urinary antigen assay for diagnosis of pneumonia in children with underlying pulmonary diseases in the absence of acute pneumococcal infection

The performance of the Binax NOW immunochromatographic test for detecting Streptococcus pneumoniae antigen in urine specimens from 103 children presenting underlying pulmonary diseases with no recent pneumococcal infection was assessed. Our data indicate that this assay is unlikely to be useful for discriminating between children with and without pneumococcal pneumonia.

Rhinovirus-associated wheezing in infancy: comparison with respiratory syncytial virus bronchiolitis

BACKGROUND

There is increasing evidence that rhinoviruses (RV) are able to cause lower airway infections and to induce wheezing in young children. There are few data on the clinical characteristics of RV infections in infants.

OBJECTIVE

The aim of the study was to compare clinical characteristics of infantile RV infection associated with wheezing and respiratory syncytial virus (RSV) bronchiolitis.

MATERIAL AND METHODS

During a 22-month study period in 1992-1993, 100 children younger than 24 months old were hospitalized with respiratory tract infection-associated wheezing. Viral etiology was originally assessed by antibody and antigen assays. Etiologic studies were later supplemented by polymerase chain reaction for RVs (in 2000) and for RSV (in 2002), studied in frozen respiratory samples. There were 81 children with adequate determinations for both RVs and RSV. Twenty-six children had RV and 24 had RSV infection, and these 50 cases form the material of the present study. Atopic dermatitis, oxygen saturation, respiratory rates and clinical scores based on wheezing and retractions and total serum IgE concentrations and blood eosinophil counts were studied in all cases on admission.

RESULTS

The children with RV infection, compared with RSV patients, were older (median, 13 versus 5 months), presented more often with atopic dermatitis (odds ratio, 16.7; 95% confidence interval, 2.22-100) and blood eosinophilia (odds ratio, 2.22; 95% confidence interval, 1.04-50). The groups did not differ from each other with regard to total serum IgE. Oxygen saturation values were lower in children with RSV infection. There were no significant differences in respiratory rates or scores combining wheezing and retractions.

CONCLUSION

RV-associated wheezing and RSV bronchiolitis, although having rather similar clinical characteristics, differ significantly with regard to age, presence of atopic dermatitis and eosinophilia during infection.

Respiratory virus infections in Stockholm during seven seasons: a retrospective study of laboratory diagnosis

A retrospective analysis of the virological findings in all respiratory samples (7303) analysed at the laboratory of Karolinska Hospital between 1993 and 2000 was performed. The findings were studied according to age and seasonal variation, and the methods were evaluated. Most samples were from children. RSV was the dominant agent, found in 34% of all samples from children 0-1 y of age. Influenza A was found in 13% of samples from the age group 2-5 y. Influenza A dominated among adults and the elderly. RSV was found only in 2% of samples from patients 81 y or older. Adenovirus was found among children and adults, but not at all among the elderly. Both antigen detection and virus isolation were performed on 79% (5776) of the samples. For diagnosis of influenza A, virus isolation was more sensitive than immunofluorescence, but for diagnosis of RSV immunofluorescence was more sensitive than virus isolation. Thus, the analysis verified that influenza A is common not only among adults and the elderly, but also among small children. RSV was an uncommon finding among the elderly. Immunofluorescence is sensitive and rapid for the diagnosis of particularly RSV among small children and influenza in all age groups.

Oral amoxicillin versus injectable penicillin for severe pneumonia in children aged 3 to 59 months: a randomised multicentre equivalency study

BACKGROUND

Injectable penicillin is the recommended treatment for WHO-defined severe pneumonia (lower chest indrawing). If oral amoxicillin proves equally effective, it could reduce referral, admission, and treatment costs. We aimed to determine whether oral amoxicillin and parenteral penicillin were equivalent in the treatment of severe pneumonia in children aged 3-59 months.

METHODS

This multicentre, randomised, open-label equivalency study was undertaken at tertiary-care centres in eight developing countries in Africa, Asia, and South America. Children aged 3-59 months with severe pneumonia were admitted for 48 h and, if symptoms improved, were discharged with a 5-day course of oral amoxicillin. 1702 children were randomly allocated to receive either oral amoxicillin (n=857) or parenteral penicillin (n=845) for 48 h. Follow-up assessments were done at 5 and 14 days after enrollment. Primary outcome was treatment failure (persistence of lower chest indrawing or new danger signs) at 48 h. Analyses were by intention-to-treat and per protocol.

FINDINGS

Treatment failure was 19% in each group (161 patients, pencillin; 167 amoxillin; risk difference -0.4%; 95% CI -4.2 to 3.3) at 48 h. Infancy (age 3-11 months; odds ratio 2.72, 95% CI 1.95 to 3.79), very fast breathing (1.94, 1.42 to 2.65), and hypoxia (1.95, 1.34 to 2.82) at baseline predicted treatment failure by multivariate analysis.

INTERPRETATION

Injectable penicillin and oral amoxicillin are equivalent for severe pneumonia treatment in controlled settings. Potential benefits of oral treatment include decreases in (1) risk of needle-borne infections; (2) need for referral or admission; (3) administration costs; and (4) costs to the family.

Etiology of community-acquired pneumonia in hospitalized school-age children: evidence for high prevalence of viral infections

BACKGROUND

Community-acquired pneumonia (CAP) in young children is most commonly associated with viral infections; however, the role of viruses in CAP of school-age children is still inconclusive.

METHODS

Seventy-five school-age children hospitalized with CAP were prospectively evaluated for the presence of viral and bacterial pathogens. Nasopharyngeal washes were examined by polymerase chain reaction for viruses and atypical bacteria. Antibody assays to detect bacterial pathogens in acute-phase and convalescent-phase serum samples were also performed.

RESULTS

A viral infection was identified in 65% of cases. Rhinovirus RNA was detected in 45% of patients; infection with another virus occurred in 31%. The most common bacterial pathogen was Mycoplasma pneumoniae, which was diagnosed in 35% of cases. Chlamydia pneumoniae DNA was not detected in any patient; results of serological tests were positive in only 2 patients (3%). Mixed infections were documented in 35% of patients, and the majority were a viral-bacterial combination.

CONCLUSIONS

The high prevalence of viral and mixed viral-bacterial infections supports the notion that the presence of a virus, acting either as a direct or an indirect pathogen, may be the rule rather than the exception in the development of CAP in school-age children requiring hospitalization.

Do rhinoviruses cause pneumonia in children?

Rhinoviruses are the most common precipitants of the common cold and have been associated with different infections of the respiratory tract, such as otitis media and sinusitis. They have also been implicated in the induction of acute asthma exacerbations, most of which are preceded by a common cold. Although in several occasions, mainly in immunocompromised hosts, severe lower respiratory tract infections have been attributed to rhinovirus infections, it is still unclear whether and to what extent these viruses contribute as pathogens in community-acquired pneumonia. Current mechanistic data suggest that rhinoviruses could be the cause of pneumonia in immunocompetent subjects. This notion is supported by epidemiological evidence, however, more clinical studies are needed to assess the actual burden.

Viral pneumoniae in children: incidence and aetiology

Community-acquired pneumonia remains a common and serious illness, which affects children of all age groups. The spectrum of causative organisms is wide and it differs according to the age of the patients. With the advent of new and improved diagnostic techniques our understanding of the aetiology of the disease has been improved considerably. Viruses have been shown to cause up to 90% of pneumonias, especially in the first year of life, with the respiratory syncytial virus to be the most important pathogen and this percentage decreases to approximately 50% by school age. Viral pneumonias frequently are complicated by bacterial infections and mixed infections are identified in 30% of the cases. The precise role of viruses and bacteria in these cases, remains to be clarified.

Rhinopharyngites de l’enfant

La rhinopharyngite désigne une inflammation modérée des voies aériennes supérieures d’origine infectieuse. Les signes habituels en sont l’obstruction nasale, la rhinorrhée, l’éternuement, la douleur pharyngée et la toux. Le terme de rhinopharyngite est spécifiquement français. Les auteurs anglo-saxons parlent de rhume (common cold) ou de upper respiratory tract infection (URI) pour décrire une inflammation aiguë des voies aériennes supérieures, et d’adénoïdite chronique (chronic adenoiditis) pour désigner une infection chronique des végétations adénoïdes responsable de rhinorrhées fébriles itératives ou d’obstruction des voies aériennes supérieures. Les rhinopharyngites aiguës non compliquées sont d’origine virale. Leur évolution spontanée est habituellement rapide et non compliquée. Elles ne nécessitent donc ni prélèvement bactériologique ni antibiothérapie systématique. En première intention, elles relèvent exclusivement d’un traitement antalgique et antipyrétique associé à des lavages des fosses nasales au sérum salé iso- ou hypertonique. Les complications des rhinopharyngites sont infectieuses, essentiellement représentées par les otites et les sinusites, et respiratoires obstructives. Le caractère fréquemment itératif des rhinopharyngites à partir de l’âge de 6 mois reflète un processus physiologique de maturation du système immunitaire. En présence de rhinopharyngites fréquentes et invalidantes, les principaux facteurs de risque devant être recherchés et si possible éradiqués sont le tabagisme passif et la fréquentation d’une collectivité d’enfants. L’adénoïdectomie n’est pas indiquée en l’absence de complications. Le développement d’antiviraux efficaces dans la prévention et dans le traitement des rhinopharyngites fait l’objet d’intenses recherches cliniques et expérimentales.

A previously undescribed coronavirus associated with respiratory disease in humans

The etiology of acute respiratory tract illnesses is sometimes unclear due to limitations of diagnostic tests or the existence of as-yet-unidentified pathogens. Here we describe the identification and characterization of a not previously recognized coronavirus obtained from an 8-mo-old boy suffering from pneumonia. This coronavirus replicated efficiently in tertiary monkey kidney cells and Vero cells, in contrast to human coronaviruses (HCoV) 229E and OC43. The entire cDNA genome sequence of the previously undescribed coronavirus was determined, revealing that it is most closely related to porcine epidemic diarrhea virus and HCoV 229E. The maximum amino acid sequence identity between ORFs of the newly discovered coronavirus and related group 1 coronaviruses ranged from 43% to 67%. Real-time RT-PCR assays were designed to test for the prevalence of the previously undescribed coronavirus in humans. Using these tests, the virus was detected in four of 139 individuals (3%) who were suffering from respiratory illness with unknown etiology. All four patients suffered from fever, runny nose, and dry cough, and all four had underlying or additional morbidity. Our data will enable the development of diagnostic tests to study the prevalence and clinical impact of this virus in humans in more detail. Moreover, it will be important to discriminate this previously undescribed coronavirus from HCoV 229E and OC43 and the severe acute respiratory syndrome coronavirus.

Epidemiology and clinical characteristics of community-acquired pneumonia in hospitalized children

OBJECTIVES

The precise epidemiology of childhood pneumonia remains poorly defined. Accurate and prompt etiologic diagnosis is limited by inadequate clinical, radiologic, and laboratory diagnostic methods. The objective of this study was to determine as precisely as possible the epidemiology and morbidity of community-acquired pneumonia in hospitalized children.

METHODS

Consecutive immunocompetent children hospitalized with radiographically confirmed lower respiratory infections (LRIs) were evaluated prospectively from January 1999 through March 2000. Positive blood or pleural fluid cultures or pneumolysin-based polymerase chain reaction assays, viral direct fluorescent antibody tests, or viral, mycoplasmal, or chlamydial serologic tests were considered indicative of infection by those organisms. Methods for diagnosis of pneumococcal pneumonia among study subjects were published by us previously. Selected clinical characteristics, indices of inflammation (white blood cell and differential counts and procalcitonin values), and clinical outcome measures (time to defervescence and duration of oxygen supplementation and hospitalization) were compared among groups of children.

RESULTS

One hundred fifty-four hospitalized children with LRIs were enrolled. Median age was 33 months (range: 2 months to 17 years). A pathogen was identified in 79% of children. Typical respiratory bacteria were identified in 60% (of which 73% were Streptococcus pneumoniae), viruses in 45%, Mycoplasma pneumoniae in 14%, Chlamydia pneumoniae in 9%, and mixed bacterial/viral infections in 23%. Preschool-aged children had as many episodes of atypical bacterial LRIs as older children. Children with typical bacterial or mixed bacterial/viral infections had the greatest inflammation and disease severity. Multivariate logistic-regression analyses revealed that high temperature (> or = 38.4 degrees C) within 72 hours after admission (odds ratio: 2.2; 95% confidence interval: 1.4-3.5) and the presence of pleural effusion (odds ratio: 6.6; 95% confidence interval: 2.1-21.2) were significantly associated with bacterial pneumonia.

CONCLUSIONS

This study used an expanded diagnostic armamentarium to define the broad spectrum of pathogens that cause pneumonia in hospitalized children. The data confirm the importance of S pneumoniae and the frequent occurrence of bacterial and viral coinfections in children with pneumonia. These findings will facilitate age-appropriate antibiotic selection and future evaluation of the clinical effectiveness of the pneumococcal conjugate vaccine as well as other candidate vaccines.

Community-acquired pneumonia in children: issues in optimizing antibacterial treatment

The treatment of community-acquired pneumonia (CAP) in children is empirical, being based on the knowledge of the etiology of CAP at different ages. As a result of currently available methods in everyday clinical practice, a microbe-specific diagnosis is not realistic in the majority of patients. Even the differentiation between viral, 'atypical' bacterial (Mycoplasma pneumoniae or Chlamydia pneumoniae) and 'typical' bacterial (Streptococcus pneumoniae) CAP is often not possible. Moreover, up to one-third of CAP cases seem to be mixed viral-bacterial or dual bacterial infections. Recent serologic studies have confirmed that S. pneumoniae is an important causative agent of CAP at all ages. M. pneumoniae is common from the age of 5 years onwards, and C. pneumoniae is common from the age of 10 years onwards. In addition to age, the etiology and treatment of CAP are dependent on the severity of the disease. Pneumococcal infections are predominant in children treated in hospital, and mycoplasmal infections are predominant in children treated at home.In ambulatory patients with CAP, amoxicillin (or penicillin V [phenoxymethylpenicillin]) is the drug of choice from the age of 4 months to 4 years, and at all ages if S. pneumoniae is the presumptive causative organism. Macrolides, preferably clarithromycin or azithromycin, are the first-line drugs from the age of 5 years onwards. In hospitalized patients who need parenteral therapy for CAP, cefuroxime (or penicillin G [benzylpenicillin]) is the drug of choice. Macrolides should be administered concomitantly if M. pneumoniae or C. pneumoniae infection is suspected. Radiologic findings and C-reactive protein (CRP) levels offer limited help for the selection of antibacterials; alveolar infiltrations and high CRP levels indicate pneumococcal pneumonia, but the lack of these findings does not rule out bacterial CAP. Most guidelines recommend antibacterials for 7-10 days (except azithromycin, which has a recommended treatment duration of 5 days). If no improvement takes place within 2 days, therapy must be reviewed.

Rhinovirus and the lower respiratory tract

Human rhinoviruses (HRVs) are well‐recognised causes of common colds and associated upper respiratory tract complications such as sinusitis and otitis media. This article reviews information linking HRV infection to illness in the lower respiratory tract. HRVs are capable of efficient replication in vitro at temperatures present in the tracheobronchial tree and have been shown to cause productive infection, elaboration of cytokines and chemokines, and up‐regulation of cell surface markers in human bronchial epithelial cells. In situ hybridisation studies have proven that HRV infection occurs in the tracheobronchial tree following experimental infection. Clinical studies report that HRV infection is the second most frequently recognised agent associated with pneumonia and bronchiolitis in infants and young children and commonly causes exacerbations of pre‐existing airways disease in those with asthma, chronic obstructive pulmonary disease or cystic fibrosis. HRV infection is associated with one‐third to one‐half of asthma exacerbations depending on age and is linked to asthma hospitalisations in both adults and children. Limited information implicates HRV infection as a cause of severe lower respiratory tract illness in older adults and in highly immunocompromised hosts, particularly bone marrow transplant recipients. More information is needed about the pathogenesis of HRV infection with regard to lower respiratory tract complications in these diverse patient groups. Given the large unmet medical need associated with HRV infections, safe and effective antiviral agents are needed for both prevention and treatment of these infections. Copyright © 2004 John Wiley & Sons, Ltd.

Incidence of community-acquired pneumonia in children caused by Mycoplasma pneumoniae: Serological results of a prospective, population-based study in primary health care

OBJECTIVE

The objective of the present study was to assess the incidence of community-acquired pneumonia (CAP) in children caused by Mycoplasma pneumoniae.

METHODOLOGY

During 12 months in 1981-1982, all CAP cases in a defined child population were registered. M. pneumoniae aetiology, initially measured by complement fixation (CF) test, was in 1999 supplemented by measurement of IgG and IgM antibodies using enzyme immunoassays (EIA).

RESULTS

M. pneumoniae was detected in 61 (30%) of 201 paediatric CAP cases, being the most common aetiological agent in those 5 years of age or over. At that age, M. pneumoniae was responsible for over 50% of cases, and over 90% of mycoplasmal cases were treated as outpatients. The EIA detected 17 new cases over and above the 44 detected by CF, while CF alone revealed 10 cases. The incidence of M. pneumoniae CAP increased with age, being over 10/1000 children at the age of 10 years or more. Co-infections with Streptococcus pneumoniae and Chlamydia pneumoniae were present in over 30% and 15%, respectively, of mycoplasmal CAP cases.

CONCLUSION

M. pneumoniae is a common cause of paediatric CAP in primary health care, and co-infections with S. pneumoniae are common. Both S. pneumoniae and M. pneumoniae should be taken into account when starting antibiotics for children with CAP.

Clinical response to antibiotic therapy for community-acquired pneumonia

Childhood community-acquired pneumonia is a common and potentially serious problem worldwide. Unless the patient has bacteraemia or pleural empyema, aetiological diagnostics are limited and antibiotic treatment is empirical. Published data on expected response to therapy are scarce. To determine the clinical response to antibiotic treatment in a developed country in otherwise healthy children with community-acquired pneumonia, we conducted a prospective study of 153 hospitalised children with pneumonia. The role of 17 microbes as potential causative agents was evaluated. The duration of fever (>37.5 degrees C) and hospitalisation were studied as objective measures of recovery. A potential aetiology was found in 83% of 153 patients: 29% of the patients had sole viral and 26% sole bacterial and 29% mixed viral-bacterial infections. The median duration of fever after the onset of antibiotic treatment (mainly penicillin G) was 14 h and the median duration of hospitalisation was 48 h. Patients with mixed viral-bacterial infection became afebrile more slowly than those with either sole viral or sole bacterial infections.

CONCLUSION

the findings indicate that in a developed country, children with pneumonia make a rapid, uneventful recovery needing only a short hospital stay. Expensive and time-consuming microbiological investigations are not required once bacterial sepsis has been excluded.

Severe acute respiratory syndrome (SARS): chest radiographic features in children

BACKGROUND

Severe acute respiratory syndrome (SARS) is a recently recognized condition of viral origin associated with substantial morbidity and mortality rates in adults. Little information is available on its radiologic manifestations in children.

OBJECTIVE

The goal of this study was to characterize the radiographic presentation of children with SARS.

MATERIALS AND METHODS

We abstracted data (n=62) on the radiologic appearance and course of SARS in pediatric patients with suspect (n=25) or probable (n=37) SARS, diagnosed in five hospital sites located in three cities: Toronto, Singapore, and Hong Kong. Available chest radiographs and thoracic CTs were reviewed for the presence of the following radiographic findings: airspace disease, air bronchograms, airways inflammation and peribronchial thickening, interstitial disease, pleural effusion, and hilar adenopathy.

RESULTS

A total of 62 patients (suspect=25, probable=37) were evaluated for SARS. Patient ages ranged from 5.5 months to 17 years and 11.5 months (average, 6 years and 10 months) with a female-to-male ratio of 32:30. Forty-one patients (66.1%) were in close contact with other probable, suspect, or quarantined cases; 10 patients (16.1%) had recently traveled to WHO-designated affected areas within 10 days; and 7 patients (11.2%) were transferred from other hospitals that had SARS patients. Three patients, who did not have close/hospital contact or travel history to affected areas, were classified as SARS cases based on their clinical signs and symptoms and on the fact that they were living in an endemic area. The most prominent clinical presentations were fever, with a temperature over 38 degrees C (100%), cough (62.9%), rhinorrhea (22.6%), myalgia (17.7%), chills (14.5%), and headache (11.3%). Other findings included sore throat (9.7%), gastrointestinal symptoms (9.7%), rigor (8.1%), and lethargy (6.5%). In general, fever and cough were the most common clinical presentations amongst younger pediatric SARS cases (age<10 years), whereas, in addition to these symptoms, headache, myalgia, sore throat, chills, and/or rigor were common in older patients (age>/=10 years). The chest radiographs of 35.5% of patients were normal. The most prominent radiological findings that were observed in the remaining patients were areas of consolidation (45.2%), often peripheral with multifocal lesions in 22.6%. Peribronchial thickening was noted on chest radiographs of 14.5% of patients. Pleural effusion was observed only in one patient (age 17 years and 11.5 months), whereas interstitial disease was not observed in any patient.

CONCLUSION

In pediatric cases, SARS manifests with nonspecific radiographic features making radiological differentiation difficult, especially from other commonly encountered childhood respiratory viral illnesses causing airspace disease. The radiographic presentation of suspected SARS cases ranged from normal to mild perihilar peribronchial thickening. The radiographic presentations, as expected, were relatively more pronounced in the SARS probable cases.

Rinofaringitis infantiles

La rinofaringitis designa una inflamación moderada de las vías respiratorias superiores de origen infeccioso. Sus signos habituales son obstrucción nasal, rinorrea, estornudos, dolor faríngeo y tos. Los autores anglosajones hablan de catarro (common cold) o de infección de vías respiratorias altas para describir una inflamación de las vías respiratorias superiores, y de adenoiditis crónica (chronic adenoiditis) para designar una infección crónica de las vegetaciones adenoides que produce rinorrea febril recidivante u obstrucción de las vías respiratorias altas. Las rinofaringitis agudas no complicadas son de origen vírico. Habitualmente su evolución espontánea es rápida y sin complicaciones. Por tanto, no hay que obtener muestras bacteriológicas ni hacer un tratamiento antibiótico sistemático. Como tratamiento de primera línea, sólo precisan analgésicos y antipiréticos asociados a lavados de las fosas nasales con suero salino isotónico o hipertónico. Las complicaciones de las rinofaringitis son infecciosas –representadas esencialmente por las otitis y las sinusitis– y respiratorias obstructivas. El carácter a menudo repetitivo de las rinofaringitis a partir de los 6 meses de edad refleja un proceso fisiológico de maduración del sistema inmunitario. Cuando existen rinofaringitis frecuentes e invalidantes, los principales factores de riesgo que se deben buscar, y de ser posible erradicar, son el tabaquismo pasivo y los contactos con una población infantil. La adenoidectomía ya no está indicada si no existen complicaciones. Se están realizando investigaciones clínicas y experimentales sobre el desarrollo de fármacos antivíricos eficaces para la prevención y el tratamiento de las rinofaringitis.

Antimicrobial resistance among pediatric respiratory tract infections: clinical challenges

Considerable development of antimicrobial resistance has occurred in the major pediatric bacterial pathogens, Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis. However, most of the respiratory infections that children suffer are viral and self-limiting, and only a small percentage of them will develop secondary bacterial infections with the pathogens listed. The challenge for rational antibiotic use is to determine which patients can be treated conservatively and which require antimicrobial intervention to avoid prolonged discomfort or development of permanent sequelae. The basis for rational use of antibiotic in the era of resistance in these major pathogens is to avoid overuse of antimicrobial agents, tailor treatment to identified pathogens as much as possible, and base empiric treatment on the disease being treated and the susceptibility of the probable pathogens at breakpoints based on pharmacokinetic and pharmacodynamic parameters. With appropriate dosing regimens based on these parameters and despite development of resistance, amoxicillin is still one of the most active oral agents against S. pneumoniae and non-beta-lactamase producing strains of H. influenzae, whereas amoxicillin-clavulanate is active against beta-lactamase-producing strains of H. influenzae and M. catarrhalis. Parenteral ceftriaxone and oral and parenteral fluoroquinolones are active against all 3 species, but fluoroquinolones should be used with utmost caution when all other options have been considered because of concerns about toxicity and development of resistance. Introduction of a 7-valent conjugate pneumococcal vaccine in the United States in 2000 reduced the prevalence of invasive pneumococcal disease in children younger than 2 years old, but, as of 2001, had not had a major impact on decreasing antimicrobial resistance.

Respiratory viruses predisposing to bacterial infections: role of neuraminidase

BACKGROUND AND METHODS

Viral-bacterial coinfections in humans are well-documented. Viral infections often lead to bacterial superinfections. In vitro and animal models for influenza, as well as molecular microbiology study of viruses and bacteria, provide an understanding of the mechanisms that explain how respiratory viruses and bacteria combine to cause disease. This article focuses on viral and bacterial combinations, particularly synergism between influenza and Streptococcus pneumoniae.

RESULTS

Potential mechanisms for synergism between viruses and bacteria include: virus destruction of respiratory epithelium may increase bacterial adhesion; virus-induced immunosuppression may cause bacterial superinfections; and inflammatory response to viral infection may up-regulate expression of molecules that bacteria utilize as receptors. Influenza and parainfluenza viruses possess neuraminidase (NA) activity, which appears to increase bacterial adherence after viral preincubation. Experimental studies demonstrate that viral NA exposes pneumococcal receptors on host cells by removing terminal sialic acids. Other studies show that inhibition of viral NA activity reduces adherence and invasion of S. pneumoniae, independently of effects on viral replication. Clinical studies reveal that influenza vaccination reduces the incidence of secondary bacterial respiratory tract infections.

CONCLUSIONS

Detection of viral factors (e.g. high NA activity) that increase the likely potential of epidemic/pandemic influenza strains for causing morbidity and mortality from secondary bacterial infections provides new possibilities for intervention. Additional study is needed to identify the mechanisms for the development of bacterial complications after infections with respiratory syncytial virus and other important respiratory viruses that lack NA activity. Prevention of bacterial superinfection is likely to depend on effective antiviral measures.

Pneumonies communautaires et infection grippale

Children without chronic or serious medical conditions are at increased risk for hospitalization during influenza seasons, mainly with respiratory tract infections. But influenza virus infections frequently remain undiagnosed, even in hospitalized patients. We prospectively studied the rate of concomitant and preceding influenza infections in children hospitalized with a community acquired pneumonia (CAP).

POPULATION AND METHODS

All 1-15-year-old children with CAP requiring hospitalization between 1st April 2000 and 2002 had nasopharyngeal aspirate for viruses, immunofluorescence and serologies for respiratory pathogens. The peak of influenza IgG measured by complement fixation (CF) is transient, and a titer of 1/64 or more indicates an acute influenza infection in the preceding weeks. Children with chronic disease were excluded and a control group of patients from outpatient clinic was measured.

RESULTS

Among 33 previously healthy children (age 4.9 years, range 1.2-14 years), 8 had a pneumococcal pneumonia, 10 a pneumonia caused by Mycoplasma pneumoniae (MP), 1 by Chlamydia pneumonia, and 8 of unknown origin. In six patients immunofluorescence was positive: Respiratory Syncitial Virus, 2, Adenovirus, 1 and Influenza A, 3 (including a patient with concomitant MP infection). Thirteen of the 33 children (39.4%) had evidence of a recent influenza A infection with CF ab > or = 1/64: with pneumococcal pneumonia, 5/10 with MP pneumonia, 3/8 with unknown origin pneumonia, 9/13 of these previous influenza infections being clinically inapparent. Only 1/30 children of control group (3.3%) had CF ab > or = 1/64.

CONCLUSION

In this study, influenza infection is the direct cause of CAP of children in 12% of cases. In other children with CAP, 39.4% of patients had an influenza infection in the preceding weeks which leads to secondary infection caused by Streptococcus pneumoniae or by MP or other pathogens.

Influenza burden in children newborn to eleven months of age in a pediatric emergency department during the peak of an influenza epidemic

BACKGROUND

The aim of this study was to determine the burden of influenza-related diseases in children 0 to 11 months of age during the peak of the 2001 to 2002 influenza epidemic.

METHODS

This was a prospective study at the Pediatric Emergency Department of Edouard Herriot tertiary teaching hospital in Lyon, France. The study included 304 infants 0 to 11 months of age. Consecutive patients were systematically enrolled during the 4 weeks of the influenza epidemic peak (Weeks 3 to 6, 2002). Influenza viruses were detected by antigen detection and virus culture from nasal swabs. Structured telephone interviews were conducted on Days 8 and 15 after virus detection. There was also a 6-month survey into the medicoadministrative database to detect late complications that required delayed hospitalization of influenza-positive children.

RESULTS

Influenza virus was detected in 99 (33%) of 304 patients (A/H3N2 in 30% and B in 3%). Nonrespiratory symptoms were the dominant clinical manifestations in 30% of influenza-positive children. One child with influenza presented with febrile seizures. Twenty (20%) children with influenza were hospitalized. Parents reported recovery from the illness in 63 and 94% of children on Days 8 and 15, respectively. The median length of an influenza episode was 8 days.

CONCLUSIONS

Our results confirm the high prevalence of influenza-related morbidity in infants during the epidemic peak. One child in three consulting to the pediatric emergency room had a virologically confirmed influenza infection regardless of the body temperature. Every fifth child with influenza was admitted to hospital, which corresponds to an admission rate of 237 per 100 000 children 0 to 11 months of age.

Influenza A community-acquired pneumonia in East London infants and young children

BACKGROUND

Community-acquired pneumonia (CAP) is common in young children, but there are few data in Europe on influenza A virus as a cause of childhood CAP. The aim of this study was to determine the relative contributions of different etiologic agents to CAP in children.

METHODS

This was a 6-month prospective study of pediatric accident and emergency and general practice consultations with a diagnosis of CAP. Nasopharyngeal aspirates for viral immunofluorescence and PCR studies and blood cultures for bacterial studies were taken from 51 children with symptoms, signs and chest radiographic features that satisfied a diagnosis of pneumonia.

RESULTS

An etiologic agent was isolated from 25 patients (49%). A viral cause was identified in 22 patients (43%), and influenza A virus and respiratory syncytial virus (RSV) were detected in 16 and 18% of all cases, respectively. Only four patients (8%) had a positive bacterial blood culture; three had Streptococcus pneumoniae and one had Neisseria meningitidis W135. Mycoplasma pneumoniae was detected in 2 children, and mixed infections were detected in 5 (10%). The use of viral PCR increased the detection rate of influenza A virus by 100%.

CONCLUSION

Influenza A virus caused more than one-third of all viral CAP cases, a rate comparable with that of RSV CAP. Viral PCR doubled the diagnostic yield of influenza A virus. The clinical burden of influenza A CAP was comparable with that of RSV CAP, as measured by the duration of fever, hospital stay and total duration of illness.

Serologically indicated pneumococcal pneumonia in children: a population-based study in primary care settings

The aim of the study was to assess age-specific incidences of community-acquired pneumonia (CAP) caused by Streptococcus pneumoniae and diagnosed serologically in a child population. The study was population-based, and prospective, and performed in primary health care settings. During a surveillance period of 12 months from 1981-1982, all pneumonia cases in a defined child population (57% urban residents) were registered prospectively. In total, 201 CAP cases were diagnosed (mean age 5.6 years; 57% boys; 58% urban residents). S. pneumoniae etiology was studied by antibody and immune complex (IC) assays to C-polysacchride (C-PS), type-specific capsular polysaccharides (CPS), and to pneumolysin (Ply), in acute and convalescent sera. Serologic evidence of S. pneumoniae etiology was indicated in 57(28%) cases, 35(61%) being mixed infections with other microbes. The distribution of pneumococcal cases was 44%, 30% and 26% in the three 5-year age groups, respectively. There were 33 (58%) males and 34 (60%) urban residents. In total, 26 cases were identified by antibody assays and 35 cases by IC assays, 26/35 being positive in acute sera. Responses to C-PS, CPS and Ply, when antibody and IC results are combined, were found equally often in 23-25 cases. The total annual incidence of pediatric S. pneumoniae CAP was 6.4/1000/year. S. pneumoniae etiology was found in 28% of the children and was similar at all ages. The incidence of pneumococcal CAP was assessed for the first time, being high (19/1000/year) in 0- to 4-year-old urban boys and rather stable (5-9/1000/year) in all other groups by age, sex and residence.

Benefits and costs of immunization of children with pneumococcal conjugate vaccine in Canada

To estimate cost-effectiveness of routine and catch-up vaccination of Canadian children with seven-valent pneumococcal conjugate vaccine, a simulation model was constructed. In base scenario (vaccination coverage: 80%, and vaccine price: 58 dollars per dose), pneumococcal disease incidence reduction would be superior to 60% for invasive infections, and to 30% for non-invasive infections, but the number of deaths prevented would be small. Annual costs of routine immunization would be 71 million dollars (98% borne by the health system). Societal benefit to cost ratio would be 0.57. Net societal costs per averted pneumococcal disease would be 389 dollars and 125,000 per life-year gained (LYG). Vaccine purchase cost is the most important variable in sensitivity analyses, and program costs would be superior to societal benefits in all likely scenarios. Vaccination would result in net savings for society, if vaccine cost is less than 30 dollars per dose. Economic indicators of catch-up programs are less favorable than for routine infant immunization.

Mucosal vaccination against encapsulated respiratory bacteria--new potentials for conjugate vaccines?

Polysaccharide (PS)-encapsulated bacteria such as Haemophilus influenzae type b (Hib), Streptococcus pneumoniae (pneumococcus), Neisseria meningitides (meningococcus) and group B streptococcus (GBS), cause a major proportion of disease in early childhood. Native PS vaccines are immunogenic and provide protection against disease in healthy adults but do not induce immunological memory. PSs are T-cell-independent antigens and do not elicit antibodies in infants and young children, but by conjugating PS to proteins they become T-cell dependent and immunogenic at an early age. Despite excellent efficacy of PS-protein conjugate vaccines against invasive disease, protection against mucosal infections such as pneumococcal otitis media has been less efficacious. Circulating PS-specific antibodies may protect against infections at mucosal sites, but mucosal immunoglobulin A antibodies may also contribute significantly to protection against mucosal infections. Mucosal immunization of experimental animals with conjugate vaccines against Hib, pneumococcus, meningococcus and GBS induces systemic and mucosal immune responses, which provide protection against carriage, otitis media and invasive disease in a variety of challenge models, providing new means for protection against encapsulated bacteria. In addition, mucosal immunization of neonatal mice with a pneumococcal conjugate and the nontoxic adjuvant LT-K63 has been superior to parenteral immunization in eliciting protective antibodies and PS-specific memory, and thus circumventing the limitations of antibody responses to PS that are responsible for enhanced susceptibility of neonates and infants to infections caused by encapsulated bacteria. Through T-cell dependent enhanced immunogenicity of PS-protein conjugate vaccines, mucosal immunization could be an attractive approach for early life immunization against encapsulated bacteria.

Five years' experience of reverse-transcriptase polymerase chain reaction in daily diagnosis of enterovirus and rhinovirus infections

To determine the efficiency of reverse-transcriptase polymerase chain reaction (RT-PCR) assays currently used in diagnosing enterovirus and rhinovirus infections, we compared results obtained with RT-PCR methods, which detect both enteroviruses and rhinoviruses simultaneously, with results obtained by conventional virus isolation. Both tests were performed on 591 specimens: 38 samples (6%) had positive results by both RT-PCR and isolation, 90 samples (15%) had positive results by RT-PCR only, and 7 samples (1%) had positive results only by virus isolation. In conclusion, RT-PCR was superior in rapidity and sensitivity to virus isolation and is recommended as the primary diagnostic tool for enterovirus and rhinovirus infections.

Mycoplasma disease and acute chest syndrome in sickle cell disease

BACKGROUND

Acute chest syndrome (ACS) is the leading cause of hospitalization, morbidity, and mortality in patients with sickle cell disease. Radiographic and clinical findings in ACS resemble pneumonia; however, etiologies other than infectious pathogens have been implicated, including pulmonary fat embolism (PFE) and infarction of segments of the pulmonary vasculature. The National Acute Chest Syndrome Study Group was designed to identify the etiologic agents and clinical outcomes associated with this syndrome.

METHODS

Data were analyzed from the prospective study of 671 episodes of ACS in 538 patients with sickle cell anemia. ACS was defined as a new pulmonary infiltrate involving at least 1 complete segment of the lung, excluding atelectasis. In addition, the patients had to have chest pain, fever >38.5C, tachypnea, wheezing, or cough. Samples of blood and deep sputum were analyzed for evidence of bacteria, viruses, and PFE. Mycoplasma pneumoniae infection was determined by analysis of paired serologies. Detailed information on patient characteristics, presenting signs and symptoms, treatment, and clinical outcome were collected.

RESULTS

Fifty-one (9%) of 598 episodes of ACS had serologic evidence of M pneumoniae infection. Twelve percent of the 112 episodes of ACS occurring in patients younger than 5 years were associated with M pneumoniae infection. At the time of diagnosis, 98% of all patients with M pneumoniae infection had fever, 78% had a cough, and 51% were tachypneic. More than 50% developed multilobar infiltrates and effusions, 82% were transfused, and 6% required assisted ventilation. The average hospital stay was 10 days. Evidence of PFE with M pneumoniae infection was seen in 5 (20%) of 25 patients with adequate deep respiratory samples for the PFE assay. M pneumoniae and Chlamydia pneumoniae was found in 16% of patients with diagnostic studies for C pneumoniae. Mycoplasma hominis was cultured in 10 (2%) of 555 episodes of ACS and occurred more frequently in older patients, but the presenting symptoms and clinical course was similar to those with M pneumoniae.

CONCLUSIONS

M pneumoniae is commonly associated with the ACS in patients with sickle cell anemia and occurs in very young children. M hominis should be considered in the differential diagnosis of ACS. Aggressive treatment with broad-spectrum antibiotics, including 1 from the macrolide class, is recommended for all patients as well as bronchodilator therapy, early transfusion, and respiratory support when clinically indicated.

Pediatric pneumonia

Respiratory disease is common in pediatrics and diagnosing pneumonia may be clinically challenging. Changes in pneumococcal resistance and immunization practices continue to change the incidence and etiologies of pneumonia. Careful attention to epidemiologic, seasonal, and specific pediatric clinical factors and using adjunct radiographs and laboratory tests should guide the emergency physician in his or her management strategy, including selection of antibiotics and inpatient or outpatient disposition.

Population-based burden of pneumonia before school entry in Schleswig-Holstein, Germany

Community-acquired pneumonia (CAP) is of predominant interest in analysing the burden of airway diseases. No population-based incidence data for children in Germany exist. In retrospective cohort studies from 1999 to 2001, parents of an entire age-class (28,000-30,000) of 5- to 7-year-old children at school entry medical examination (S1) in a complete federal state (Schleswig-Holstein, population 2.77 million) were interviewed by the Children and Adolescent Service of the Public Health Service. CAP was defined as pneumonia diagnosed by a physician at the time it occurred. The proportion of children investigated (participation rate) was 82.0-86.1%. The CAP-positive rate was 6.7-7.4%, 6.9-8.2% of whom had recurrent CAP. The mean age at first CAP was 36.4-39.4 months (median 42 months). This resulted in a population-based incidence for the age groups 0-1 year and 0-5 years (under 5) of 1,664-1,932 and 1,369-1,690 per 100,000, respectively; 93.7-95.9% received antibiotics. For each percent of CAP, 458 days (1999), 312 days (2000) and 319 days (2001) of at least one parent's work were lost, respectively.

CONCLUSIONS

Despite a relatively weak case definition, the population-based incidence of CAP before school entry was the same as recently reported form California and about 30-50% of that reported 20 to 40 years ago in the USA and Finland.

Usefulness of urinary antigen detection by an immunochromatographic test for diagnosis of pneumococcal pneumonia in children

We evaluated an immunochromatographic assay detecting pneumococcal antigen in urine samples from children diagnosed with pneumococcal pneumonia. The sensitivity and specificity of the immunochromatographic test with nonconcentrated urine (NCU) were 86.7 and 62.9%, respectively; with concentrated urine (CU), they were 100 and 11.7%, respectively. Pneumococcal antigen was also detected in 42.5% of NCU and 87.1% of CU samples from nasopharyngeal carriers. This is a nonspecific test for the diagnosis of pneumococcal pneumonia in children, particularly the very young.

Quantitative detection of Moraxella catarrhalis in nasopharyngeal secretions by real-time PCR

The recognition of Moraxella catarrhalis as an important cause of respiratory tract infections has been protracted, mainly because it is a frequent commensal organism of the upper respiratory tract and the diagnostic sensitivity of blood or pleural fluid culture is low. Given that the amount of M. catarrhalis bacteria in the upper respiratory tract may change during infection, quantification of these bacteria in nasopharyngeal secretions (NPSs) by real-time PCR may offer a suitable diagnostic approach. Using primers and a fluorescent probe specific for the copB outer membrane protein gene, we detected DNA from serial dilutions of M. catarrhalis cells corresponding to 1 to 10(6) cells. Importantly, there was no difference in the amplification efficiency when the same DNA was mixed with DNA from NPSs devoid of M. catarrhalis. The specificity of the reaction was further confirmed by the lack of amplification of DNAs from other Moraxella species, nontypeable Haemophilus influenzae, H. influenzae type b, Streptococcus pneumoniae, Streptococcus oralis, Streptococcus pyogenes, Bordetella pertussis, Corynebacterium diphtheriae, and various Neisseria species. The assay applied to NPSs from 184 patients with respiratory tract infections performed with a sensitivity of 100% and a specificity of up to 98% compared to the culture results. The numbers of M. catarrhalis organisms detected by real-time PCR correlated with the numbers detected by semiquantitative culture. This real-time PCR assay targeting the copB outer membrane protein gene provided a sensitive and reliable means for the rapid detection and quantification of M. catarrhalis in NPSs; may serve as a tool to study changes in the amounts of M. catarrhalis during lower respiratory tract infections or following vaccination against S. pneumoniae, H. influenzae, or N. meningitidis; and may be applied to other clinical samples.

Mycoplasma pneumoniae ecephalitis

Mycoplasma pneumoniae causes between 5 and 10 percent of acute childhood encephalitis in Europe and North America. Encephalitis due to this organism may be caused by direct infection of the brain, immune-mediated brain injury or thromboembolic phenomenon. The prognosis is guarded with 20 to 60 percent suffering neurologic sequelae. The diagnosis of M. pneumoniae encephalitis should be based on strong evidence of M. pneumoniae infection that includes detection of the organism in culture or using molecular detection techniques in addition to serology and exclusion of other potential etiologies. Antibiotic therapy should be considered for all children with suspected M. pneumoniae encephalitis; antibiotics with good central nervous system (CNS) penetration such as ciprofloxacin, doxycycline, chloramphenicol or azithromycin are appropriate under most circumstances. Immune modulating therapies, such as corticosteroids, intravenous immune globulin or plasmapharesis, should be considered in those with immune-mediated syndromes such as acute disseminated encephalomyelitis.

Impact of travel on international spread of antimicrobial resistance

Antimicrobial resistance, an escalating problem worldwide, affects a broad range of human diseases. Excessive and inappropriate drug usage is the key driver for the emergence of resistant organisms. Travel, trade and mass migration form an important mode for their spread. The use of molecular biology provides the means of understanding the genesis and spread of the genes for drug resistance. Antimicrobial use in veterinary practice as food additives causes selection of resistant zoonotic pathogens that may spread to humans. Comprehensive surveillance systems should be designed and implemented at local and national levels and a national resistance surveillance database operationalized. There is also need for better regulation of the use of antibiotics and education of the medical fraternity, veterinarians and the public in the appropriate use of antimicrobials.

Influenza A and B virus infections in children

To obtain data on the clinical manifestations of infection, the age distribution, and the underlying conditions of children with influenza severe enough to lead to hospital referral, we performed a retrospective study of children treated at Turku University Hospital (Turku, Finland) in 1980-1999. Influenza A or B antigen was detected in the nasopharyngeal aspirates of 683 of the 15,420 children studied. The median age of children with influenza A was 2.0 years (n=544), and that of children with influenza B was 4.2 years (n=139) (P<.001). One-fourth of the children had an underlying medical condition. High fever, cough, and rhinorrhea were the most frequently recorded symptoms. Acute otitis media developed in 24% of the children, and pneumonia developed in 9% of the children. The study shows that the majority of patient hospitalizations for pediatric influenza involve previously healthy infants and young children. Laboratory confirmation of influenza is particularly important for children because the clinical presentation of the infection is less characteristic than that seen in adults.

Comparative randomized trial of azithromycin versus erythromycin and amoxicillin for treatment of community-acquired pneumonia in children

Our objective was to compare the clinical efficacy of azithromycin vs. erythromycin and amoxicillin in the treatment of presumed bacterial community-acquired pneumonia in ambulatory children, and to evaluate the etiologies of these illnesses. One hundred and ten children, aged 1 month to 14 years, were enrolled between January 1996-January 1999. Children were distributed into two groups according to clinical and radiological patterns: classic or atypical pneumonia. Patients with classic pneumonia were randomly assigned to receive oral amoxicillin 75 mg/kg/day for 7 days, or azithromycin 10 mg/kg/day for 3 days; patients with atypical pneumonia received azithromycin 10 mg/kg/day for 3 days, or erythromycin 50 mg/kg/day for 14 days. Chest X-ray, clinical, and laboratory parameters were obtained on enrollment. Clinic visits were performed on days 3, 7, and 14, and chest X-ray follow-up on days 7 and 14. Microbiological diagnosis of classic pathogens was based on blood and bronchial secretion cultures. The diagnosis of atypical pathogens C. pneumoniae, C. trachomatis, and M. pneumoniae was based on PCR and serologic tests.Forty-seven children met the criteria for classic pneumonia (23 children received azithromycin, and 24 received amoxicillin), and 59 children had atypical pneumonia (33 children were treated with azithromycin, and 26 with erythromycin). Demographic characteristics at enrollment were similar between children with classic pneumonia treated with azithromycin and erythromycin and children treated with azithromycin and erythromycin for atypical pneumonia. However, on day 7, children with classic pneumonia who received azithromycin normalized their chest X-ray more often than those who received amoxicillin (81.0% vs. 60.9%, respectively, P = 0.009). The same was true for children with atypical pneumonia; their chest X-rays had normalized by day 14 (100% in those with azithromycin vs. 81% in those with erythromycin, P = 0.059). Also, children with atypical pneumonia treated with azithromycin had earlier cessation of cough than children treated with erythromycin (3.6 +/- 1.9 vs. 5.5 +/- 3.6 days respectively, P = 0.02). There were only three children with side effects (mild diarrhea, all in the erythromycin group). Etiological agents were identified in 41% of children. In conclusion, azithromycin is an effective therapeutic option for the treatment of community-acquired classic and atypical pneumonia in children.

The common cold

Despite great advances in medicine, the common cold continues to be a great burden on society in terms of human suffering and economic losses. Of the several viruses that cause the disease, the role of rhinoviruses is most prominent. About a quarter of all colds are still without proven cause, and the recent discovery of human metapneumovirus suggests that other viruses could remain undiscovered. Research into the inflammatory mechanisms of the common cold has elucidated the complexity of the virus-host relation. Increasing evidence is also available for the central role of viruses in predisposing to complications. New antivirals for the treatment of colds are being developed, but optimum use of these agents would require rapid detection of the specific virus causing the infection. Although vaccines against many respiratory viruses could also become available, the ultimate prevention of the common cold seems to remain a distant aim.

Rhinovirus-induced wheezing in infancy--the first sign of childhood asthma?

BACKGROUND

Although known as common causes of upper respiratory infections, rhinoviruses, enteroviruses, and corona-viruses are poorly studied as inducers of wheezing in infants, and their possible role in the development of childhood asthma has not been investigated.

OBJECTIVE

The purposes of this study were to assess the occurrence of RV, enterovirus, and coronavirus infections in wheezing infants and to evaluate the association of these viral findings with early school-age asthma.

METHODS

In 1999, outcome in relation to asthma was studied in 82 of 100 initially recruited children who had been hospitalized for wheezing in infancy during the period 1992-1993. In 2000, etiologic viral studies regarding the index episode of wheezing were supplemented by rhinovirus, enterovirus, and coronavirus detection by RT-PCR from frozen nasopharyngeal aspirates in 81 of the children for whom adequate samples were available. Of these children, 66 had participated in the follow-up in 1999.

RESULTS

Rhinoviruses were identified in 27 (33%) of the 81 children, enteroviruses in 10 (12%), and coronaviruses in none. Rhinoviruses were present as single viral findings in 22 (81%) of the 27 rhinovirus-positive cases, and rhinovirus infections were associated with the presence of atopic dermatitis in infancy. Enteroviruses were commonly encountered in mixed infections and had no association with atopy. As single viral findings, rhinoviruses were associated with the development of asthma (P =.047; odds ratio, 4.14; 95% CI, 1.02-16.77 versus rhinovirus-negative cases [by logistic regression adjusted for age, sex, and atopic dermatitis on entry)].

CONCLUSION

Our results present rhinoviruses as important inducers of wheezing even in infancy. The association with atopy and subsequent asthma calls for reevaluation of the role of rhinoviruses in the development of asthma.

Characteristics of Streptococcus pneumoniae and atypical bacterial infections in children 2-5 years of age with community-acquired pneumonia

The characteristics of community-acquired pneumonia associated with Streptococcus pneumoniae infection were compared with those associated with atypical bacterial infection and with mixed S. pneumoniae-atypical bacterial infection in 196 children aged 2-5 years. S. pneumoniae infections were diagnosed in 48 patients (24.5%); atypical bacterial infections, in 46 (23.5%); and mixed infections, in 16 (8.2%). Although white blood cell counts and C-reactive protein levels were higher in patients with pneumococcal infections, no other clinical, laboratory, or radiographic characteristic was significantly correlated with the different etiologic diagnoses. There was no significant difference in the efficacy of the different treatment regimens followed by children with S. pneumoniae infection, whereas clinical failure occurred significantly more frequently among children with atypical bacterial or mixed infection who were not treated with a macrolide. This study shows the major role of both S. pneumoniae and atypical bacteria in the development of community-acquired pneumonia in young children, the limited role of clinical, laboratory, and radiological features in predicting etiology, and the importance of the use of adequate antimicrobial agents for treatment.

The new pneumococcal vaccine

Pneumococcal disease is now the leading cause of vaccine-preventable bacterial disease in children worldwide. Although a pneumococcal polysaccharide vaccine has been available for over three decades, its use has been limited due to poor immunogenicity in the most vulnerable children, aged less than 2 years. The prevalence of pneumococcal disease worldwide and the alarming global escalation of multiresistant strains of Streptococcus pneumoniae (pneumococcus) during the past decade have provided the impetus for the development and application of a new pneumococcal vaccine. The outstanding success of Haemophilus influenzae type b (Hib) conjugate vaccine in the control of invasive Hib disease is a reason to be optimistic that the pneumococcal conjugate vaccines will achieve similar results for the control of invasive pneumococcal disease. Remarkable efficacy against invasive pneumococcal disease with a seven-valent pneumococcal conjugate vaccine was demonstrated in infants and toddlers in the USA, and in February 2000 the first pneumococcal conjugate vaccine was licensed. Licensure and widespread use is likely to follow in other countries in which there is a need and the means to afford this live-saving vaccine. Active disease surveillance must be sustained globally, while active research, development of other multivalent conjugate formulations and the search for new candidate protein-based vaccines are in progress.

The future of pneumococcal conjugate vaccines for prevention of pneumococcal diseases in infants and children

Seven-valent pneumococcal conjugate vaccine (PCV7) was licensed in February 2000. In June 2000, the Advisory Committee on Immunization Practices and the American Academy of Pediatrics recommended the universal administration of pneumococcal conjugate vaccine for all children 23 months of age and younger and for children 24 to 59 months of age who are at high risk for serious pneumococcal disease. Since then, >23 million doses have been administered in the United States. Postlicensure surveillance of invasive pneumococcal disease (IPD) in the United States from the Active Bacterial Core Surveillance program at the Centers for Disease Control and Prevention and the Northern California Kaiser Permanente Vaccine Study Center has reported a decline in IPD and in pneumococcal disease incidence as a result of vaccine serotypes, respectively. During this period, issues critical to the long-term success of PCV7 have become more relevant: Will PCV7 be as effective in groups of children who are at high risk for IPD as in healthy children? Will nonvaccine types replace vaccine serotypes in the nasopharynx and in disease? Why are the results of the clinical trials different for IPD and for acute otitis media? How many doses of PCV7 and what concentrations of antibody are necessary for protection? Will universal administration of PCV7 to children younger than 2 years reduce antimicrobial drug resistance and alter prescribing patterns of physicians for febrile infants? Have there been unanticipated adverse events or benefits observed? The purpose of this report is to review the current data available to address these questions and to identify gaps that will require additional knowledge to determine the ultimate value of pneumococcal conjugate vaccines in reducing the burden of pneumococcal disease in infants and children.