Etiology of community-acquired pneumonia in children based on antibody responses to bacterial and viral antigens

Comparison of serological assays using pneumococcal proteins or polysaccharides for detection of Streptococcus pneumoniae infection in children with community-acquired pneumonia

The aim of this study was to compare the results of serological assays using pneumococcal proteins or polysaccharides for the detection of pneumococcal infection in childhood pneumonia. Serological assays measured IgG against eight pneumococcal proteins (Ply,CbpA,PspA1,PspA2,PcpA,PhtD,StkP-C,PcsB-N), C-polysaccharide [in the whole study population, n = 183], or 19 pneumococcal capsular polysaccharides (1,2,4,5,6B,7F,8,9 V,10A,11A,12F,14,15B,17F,18C,19F,20,23F,33F) [only in a subgroup of patients, n = 53] in paired serum samples of children aged <5 years-old hospitalized with clinical and radiological diagnosis of community-acquired pneumonia. We also performed an inhibition of binding test with the anti-capsular polysaccharide assay in order to confirm the specificity of the antibody responses detected. Invasive pneumococcal pneumonia was investigated by blood culture and PCR (ply-primer). Among 183 children, the anti-protein assay detected antibody response in 77/183(42.1%) patients and the anti-C-polysaccharide assay in 28/183(15.3%) patients. In a subgroup of 53 children, the anti-protein assay detected response in 32/53(60.4%) patients, the anti-C-polysaccharide assay in 11/53(20.8%) patients, and the anti-capsular polysaccharide in 25/53(47.2%) patients. Simultaneous antibody responses against ≥2 different capsular polysaccharides were detected in 11/53(20.8%) patients and this finding could not be explained by cross-reactivity between different serotypes. Among 13 patients with invasive pneumococcal pneumonia, the sensitivity of the anti-protein assay was 92.3%(12/13), of the anti-C-polysaccharide assay 30.8%(4/13), and of the anti-capsular polysaccharide assay 46.2%(6/13). The serological assay using pneumococcal proteins is more sensitive for the detection of pneumococcal infection in children with pneumonia than the assay using pneumococcal polysaccharides. Future studies on childhood pneumonia aetiology should consider applying serological assays using pneumococcal proteins.

Etiologic spectrum and occurrence of coinfections in children hospitalized with community-acquired pneumonia

Background

Co-infections are common in childhood community acquired pneumonia (CAP). However, their etiological pattern and clinical impact remains inconclusive.

Methods

Eight hundred forty-six consecutive children with CAP were evaluated prospectively for the presence of viral and bacterial pathogens. Nasopharyngeal aspirates were examined by direct immunofluorescence assay or polymerase chain reaction (PCR) for viruses. PCR of nasopharyngeal aspirates and enzyme-linked immunosorbent assays were performed to detect M. pneumoniae. Bacteria was detected in blood, bronchoalveolar lavage specimen, or pleural fluid by culture.

Results

Causative pathogen was identified in 70.1% (593 of 846) of the patients. The most commonly detected pathogens were respiratory syncytial virus (RSV) (22.9%), human rhinovirus (HRV) (22.1%), M. pneumoniae (15.8%). Coinfection was identified in 34.6% (293 of 846) of the patients. The majority of these (209 [71.3%] of 293) were mixed viral-bacterial infections. Age < 6 months (odds ratio: 2.1; 95% confidence interval: 1.2–3.3) and admission of PICU (odds ratio: 12.5; 95% confidence interval: 1.6–97.4) were associated with mix infection. Patients with mix infection had a higher rate of PICU admission.

Conclusions

The high mix infection burden in childhood CAP underscores a need for the enhancement of sensitive, inexpensive, and rapid diagnostics to accurately identify pneumonia pathogens.

Pediatric Community-Acquired Pneumonia in the United States: Changing Epidemiology, Diagnostic and Therapeutic Challenges, and Areas for Future Research

Community-acquired pneumonia (CAP) is one of the most common serious infections in childhood. This review focuses on pediatric CAP in the United States and other industrialized nations, specifically highlighting the changing epidemiology of CAP, diagnostic and therapeutic challenges, and areas for further research.

Chlamydia psittaci (psittacosis) as a cause of community-acquired pneumonia: a systematic review and meta-analysis

Psittacosis is a zoonotic infectious disease caused by the transmission of the bacterium Chlamydia psittaci from birds to humans. Infections in humans mainly present as community-acquired pneumonia (CAP). However, most cases of CAP are treated without diagnostic testing, and the importance of C. psittaci infection as a cause of CAP is therefore unclear. In this meta-analysis of published CAP-aetiological studies, we estimate the proportion of CAP caused by C. psittaci infection. The databases MEDLINE and Embase were systematically searched for relevant studies published from 1986 onwards. Only studies that consisted of 100 patients or more were included. In total, 57 studies were selected for the meta-analysis. C. psittaci was the causative pathogen in 1·03% (95% CI 0·79-1·30) of all CAP cases from the included studies combined, with a range between studies from 0 to 6·7%. For burden of disease estimates, it is a reasonable assumption that 1% of incident cases of CAP are caused by psittacosis.

Microbial Etiology of Community-Acquired Pneumonia Among Infants and Children Admitted to the Pediatric Hospital, Ain Shams University

BACKGROUND

While recognizing the etiology of community-acquired pneumonia is necessary for formulating local antimicrobial guidelines, limited data is published about this etiology in Egyptian pediatric patients.

OBJECTIVES

To determine the frequency of bacterial and viral pathogens causing community-acquired pneumonia (CAP) among immunocompetent Egyptian infants and preschool children.

METHODS

Ninety infants and preschool-age children admitted to our hospital with CAP were prospectively included in the study. Etiological agents were identified using conventional bacteriological identification methods and IgM antibodies detection against common atypical respiratory bacteria and viruses.

RESULTS

An etiology was identified in 59 patients (65.5%). Bacterial pathogens were detected in 43 (47.8%) of the cases while viral pathogens were detected in 23 (25.5%). Coinfection with more than one etiologic agent was evident in seven patients (7.8%). The most common typical bacterial cause of pneumonia was Staphylococcus aureus (n = 12, 13.3%), followed by Streptococcus pneumoniae and Klebsiella pneumoniae (n = 7, 7.8%, each). The commonest atypical bacterium was Mycoplasma pneumoniae (n = 10, 11.1%), whereas the commonest viral etiology was influenza viruses (n = 11, 12.2%).

CONCLUSION

Although we could not determine the causative agent in some studied cases, this study provides preliminary data regarding the spectrum and frequency of microorganisms causing CAP in Egyptian infants and preschool children.

Etiology of Pneumonia in a Pediatric Population with High Pneumococcal Vaccine Coverage: A Prospective Study

BACKGROUND

Improved Childhood Immunizations Programs, especially the introduction of pneumococcal vaccination, better diagnostic methods and the importance of reduced antibiotic misuse, make this a critical time to increase knowledge on the etiology of pediatric pneumonia. Our main objective was to identify the contribution of various microbiological species that causes pneumonia in previously healthy children and adolescents in a population with high pneumococcal conjugate vaccine coverage.

METHODS

This prospective, observational study enrolled patients with clinical and radiological signs of pneumonia over a 2-year period. Both inpatients and outpatients were included. Paired sera, nasopharyngeal polymerase chain reaction and bacterial cultures from blood and pleura were analyzed to detect potential viral and bacterial causative pathogens.

RESULTS

TWO HUNDRED AND SIXTY-FIVE: cases of clinical and radiological verified pneumonia were identified. The pneumococcal vaccine coverage was 85%. We identified a causative pathogen in 84.2% of all cases; 63.4% with single viral etiology, 11.3% with pneumococcus and 7.5% with mycoplasma infection. Respiratory syncytial virus was the most common pathogen in children younger than 5 years, whereas mycoplasma was the most common in older children.

CONCLUSIONS

We identified the majority of 265 cases with radiology proven pneumonia as single viral infections, predominantly respiratory syncytial virus and a much lower proportion of bacterial causes. These findings may impact pneumonia management guidelines in areas where widespread pneumococcal vaccination is provided and contribute to reduced antibiotic overuse in pediatric pneumonia.

Incidence and Risk Factors for Respiratory Syncytial Virus and Human Metapneumovirus Infections among Children in the Remote Highlands of Peru

INTRODUCTION

The disease burden and risk factors for respiratory syncytial virus (RSV) and human metapneumovirus (MPV) infections among children living in remote, rural areas remain unclear.

MATERIALS AND METHODS

We conducted a prospective, household-based cohort study of children aged <3 years living in remote rural highland communities in San Marcos, Cajamarca, Peru. Acute respiratory illnesses (ARI), including lower respiratory tract infection (LRTI), were monitored through weekly household visits from March 2009 through September 2011. Nasal swabs collected during ARI/LRTI were tested for RSV, MPV, and other respiratory viruses using real-time RT-PCR. Incidence rates and rate ratios were calculated using mixed effects Poisson regression.

RESULTS

Among 892 enrolled children, incidence rates of RSV and MPV ARI were 30 and 17 episodes per 100 child-years, respectively. The proportions of RSV and MPV ARI that presented as LRTI were 12.5% and 8.9%, respectively. Clinic visits for ARI and hospitalizations were significantly more frequent (all p values <0.05) among children with RSV (clinic 41% and hospital 5.3%) and MPV ARI (38% and 3.5%) when compared with other viral infections (23% and 0.7%) and infections without virus detected (24% and 0.6%). In multivariable analysis, risk factors for RSV detection included younger age (RR 1.02, 95% CI: 1.00-1.03), the presence of a smoker in the house (RR 1.63, 95% CI: 1.12-2.38), residing at higher altitudes (RR 1.93, 95% CI: 1.25-3.00 for 2nd compared to 1st quartile residents; RR 1.98, 95% CI: 1.26-3.13 for 3rd compared to 1st quartile residents). Having an unemployed household head was significantly associated with MPV risk (RR 2.11, 95% CI: 1.12-4.01).

CONCLUSION

In rural high altitude communities in Peru, childhood ARI due to RSV or MPV were common and associated with higher morbidity than ARI due to other viruses or with no viral detections. The risk factors identified in this study may be considered for interventional studies to control infections by these viruses among young children from developing countries.

Fever in the pediatric patient

Fever is the most common reason that children and infants are brought to emergency departments. Emergency physicians face the challenge of quickly distinguishing benign from life-threatening conditions. The management of fever in children is guided by the patient's age, immunization status, and immune status as well as the results of a careful physical examination and appropriate laboratory tests and radiographic views. In this article, the evaluation and treatment of children with fevers of known and unknown origin are described. Causes of common and dangerous conditions that include fever in their manifestation are also discussed.

Evaluation of a WHO-validated serotype-specific serological assay for the diagnosis of pneumococcal etiology in children with community-acquired pneumonia

BACKGROUND

The etiologic diagnosis of community-acquired pneumonia (CAP) remains challenging in children because blood cultures have low sensitivity. Novel approaches are needed to confirm the role of Streptococcus pneumoniae.

METHODS

In this study, pneumococcal etiology was determined by serology using a subset of blood samples collected during a prospective multicentre observational study of children <15 years of age hospitalized in Belgium with radiogram-confirmed CAP. Blood samples were collected at admission and 3-4 weeks later. Pneumococcal (P)-CAP was defined in the presence of a positive blood or pleural fluid culture. Serotyping of S. pneumoniae isolates was done with the Quellung reaction. Serological diagnosis was assessed for 9 serotypes using World Health Organization-validated IgG and IgA serotype-specific enzyme-linked immunosorbent assays (ELISAs).

RESULTS

Paired admission/convalescent sera from 163 children were evaluated by ELISA (35 with proven P-CAP and 128 with nonproven P-CAP). ELISA detected pneumococci in 82.8% of patients with proven P-CAP. The serotypes identified were the same as with the Quellung reaction in 82% and 59% of cases by IgG ELISA and IgA ELISA, respectively. Overall, ELISA identified a pneumococcal etiology in 55% of patients with nonproven P-CAP. Serotypes 1 (51.6%), 7F (19%) and 5 (15.7%) were the most frequent according to IgG ELISA.

CONCLUSIONS

In conclusion, the serological assay allows recognition of pneumococcal origin in 55% of CAP patients with negative culture. This assay should improve the diagnosis of P-CAP in children and could be a useful tool for future epidemiological studies on childhood CAP etiology.

Respiratory viral and pneumococcal coinfection of the respiratory tract: implications of pneumococcal vaccination

The interactions between Streptococcus pneumoniae and other respiratory pathogens have been studied in vitro, in animal models and in humans - including epidemiologic and vaccine probe studies. Interactions of pneumococcus with respiratory viruses are common, and many mechanisms have been suggested to explain this phenomenon. The aim of this review is to explore pneumococcal interactions with respiratory viruses and consider the potential role that the pneumococcal polysaccharide-protein conjugate vaccine may play in modifying pneumococcal-respiratory viral interactions.

Community-Acquired Pneumonia in the Conjugate Vaccine Era

Community-acquired pneumonia (CAP) remains one of the most common serious infections encountered among children worldwide. In this review, we highlight important literature and recent scientific discoveries that have contributed to our current understanding of pediatric CAP. We review the current epidemiology of childhood CAP in the developed world, appraise the state of diagnostic testing for etiology and prognosis, and discuss disease management and areas for future research in the context of recent national guidelines.

Legionnaires’ Disease

Infection with Legionella spp. is an important cause of serious community- and hospital-acquired pneumonia, occurring sporadically and in outbreaks. Outbreaks of Legionnaires' disease have recently received considerable media attention, and some factors indicate that the problem will increase in future. Infection with Legionella spp. ranks among the three most common causes of severe pneumonia in the community setting, and is isolated in 1-40% of cases of hospital-acquired pneumonia. Underdiagnosis and underreporting are high. Only 2-10% of estimated cases are reported. Detection of a single case should not be considered an isolated sporadic event, but rather indicative of unrecognized cases. There are no clinical features unique to Legionnaires' disease; however, suspicion should be raised by epidemiologic information commensurate with the diagnosis and the presence of headache, confusion, hyponatremia, elevated creatine kinase and/or severe pneumonia. An arterial oxygen partial pressure <60mm Hg on presentation and progression of pulmonary infiltrates despite appropriate antibacterial therapy should always alert clinicians to this cause.Macrolides, fluoroquinolones and rifampin (rifampicin) are the most widely used drugs in treatment. Fluoroquinolones or azithromycin are the treatment of choice in immunosuppressed patients and those with severe pneumonia. Incorporation of the legionella urinary antigen test in emergency departments in hospitals and progressive improvement in this test will, in the near future, permit appropriate diagnosis and treatment of this frequent, sometimes severe, illness.

Procalcitonin predicts response to beta-lactam treatment in hospitalized children with community-acquired pneumonia

Background

Antibiotic treatment of community-acquired pneumonia (CAP) in children remains mostly empirical because clinical and paraclinical findings poorly discriminate the principal causes of CAP. Fast response to beta-lactam treatment can be considered a proxy of pneumococcal aetiology. We aimed to identify the best biological predictor of response to beta-lactam therapy in children hospitalized for CAP.

Methods

A retrospective, single-centre cohort study included all consecutive patients 1 month to 16 years old hospitalized in a teaching hospital in Paris, France, because of CAP empirically treated with a beta-lactam alone from 2003 to 2010. Uni- and multivariate analyses were used to study the ability of routine biological parameters available in the Emergency Department to predict a favourable response to beta-lactam (defined as apyrexia within 48 hours of treatment onset).

Results

Among the 125 included patients, 85% (106) showed a favourable response to beta-lactam. In multivariate logistic regression, we found procalcitonin (PCT) the only independent predictor of apyrexia (p = 0.008). The adjusted odds ratio for the decadic logarithm of PCT was 4.3 (95% CI 1.5–12.7). At ≥3 ng/mL, PCT had 55.7% sensitivity (45.7–65.3), 78.9% specificity (54.4–93.9), 93.7% positive predictive value (84.5–98.2), 24.2% negative predictive value (14.2–36.7), 2.64 positive likelihood ratio (1.09–6.42) and 0.56 negative likelihood ratio (0.41–0.77). In the 4 children with a PCT level ≥3 ng/mL and who showed no response to beta-lactam treatment, secondary pleural effusion had developed in 3, and viral co-infection was documented in 1.

Conclusions

PCT is the best independent biologic predictor of favourable response to beta-lactam therapy in children hospitalized for CAP. Thus, a high PCT level is highly suggestive of pneumococcal aetiology. However, a 3-ng/mL cut-off does not seem compatible with daily medical practice, and additional research is needed to further define the role of PCT in managing CAP in children.

A practical approach estimating etiologic agents using real-time PCR in pediatric inpatients with community-acquired pneumonia

To evaluate pathogens in pediatric inpatients with community-acquired pneumonia (CAP), an Acute Respiratory Diseases Study Group organized by ten Japanese medical institutions devised a rapid, reliable process based on real-time PCR results in nasopharyngeal swab samples plus admission blood test results. From April 2008 to April 2009, we enrolled 903 children with CAP based on chest radiographs and clinical findings who were hospitalized within 5 days of onset. Comprehensive real-time PCR was used to detect 6 bacteria and 11 respiratory viruses. The swab specimens also were used for bacterial cultures. After initial determination of presence or absence of viral and mycoplasmal infections, significant bacterial contributions were defined by bacterial identification, clinical efficacy of antimicrobial agent, and reference to blood test results. Children were stratified by age: below 1 year, 1 year, 2-5 years, or at least 6 years old. Among patients studied, 34.4 % were diagnosed with viral infection; 21.8 %, bacterial infection; 17.5 %, viral/bacterial co-infection; 5.9 %, mycoplasmal infection; 0.3 %, mycoplasmal/bacterial co-infection; and 1.7 %, viral/mycoplasmal co-infection. The remaining 18.4 % had unknown pathogens. Purely viral infection was suggested mainly in infants younger than 1 year; mycoplasmal infection typically occurred in children at least 6 years old. Our results suggest usefulness of real-time PCR for nasopharyngeal samples together with blood tests in estimating etiologic agents in clinical settings.

The management of community-acquired pneumonia in infants and children older than 3 months of age: clinical practice guidelines by the Pediatric Infectious Diseases Society and the Infectious Diseases Society of America

Evidenced-based guidelines for management of infants and children with community-acquired pneumonia (CAP) were prepared by an expert panel comprising clinicians and investigators representing community pediatrics, public health, and the pediatric specialties of critical care, emergency medicine, hospital medicine, infectious diseases, pulmonology, and surgery. These guidelines are intended for use by primary care and subspecialty providers responsible for the management of otherwise healthy infants and children with CAP in both outpatient and inpatient settings. Site-of-care management, diagnosis, antimicrobial and adjunctive surgical therapy, and prevention are discussed. Areas that warrant future investigations are also highlighted.

Bronconeumopatías agudas del niño

Las infecciones infantiles afectan con frecuencia al aparato respiratorio inferior. Las clasificaciones convencionales, basadas en el tipo de afección anatómica, radiológica y etiopatogénica, permiten definir entidades clínicas (bronquitis, bronquiolitis, neumopatía); sin embargo, la evaluación de la gravedad del proceso es lo más útil para decidir el tipo y la rapidez del tratamiento. Aunque la etiología viral es la más frecuente, la estrategia fundamental para reducir la morbilidad e incluso la mortalidad de las infecciones respiratorias bajas se basa en el tratamiento adecuado de las neumonías bacterianas. Ante la ausencia de especificidad, es indispensable, cuando esté indicado, recurrir a una antibioticoterapia inicial probabilística que incluya el neumococo. En el niño, las muestras no suelen proceder del parénquima pulmonar y, además, la recogida de las secreciones bronquiales durante los primeros años de vida no es de buena calidad. Al contrario de lo que ocurre con los virus, el examen bacteriológico de las secreciones de las vías respiratorias altas es poco útil, porque los niños suelen ser portadores de gérmenes que pueden causar neumopatías. Los datos clínicos y radiológicos sólo pueden sugerir el diagnóstico. El desarrollo de técnicas que detectan antígenos microbianos o la búsqueda de material genético por biología molecular han permitido mejorar de manera significativa la identificación del patógeno responsable y la elección del tratamiento adecuado. Algunos grupos particulares de pacientes pueden padecer una afección respiratoria por agentes infecciosos inusuales o, incluso, oportunistas. Una proporción importante de la afectación respiratoria del adulto puede atribuirse a las agresiones pulmonares sufridas durante su infancia. La aplicación de vacunas, en especial, la antigripal y la antineumocócica, es fundamental para la prevención de estas afecciones respiratorias.

Epidemiological and economic burden of pneumococcal diseases in Canadian children

BACKGROUND

With the arrival of a new conjugate pneumococcal vaccine, it is important to estimate the burden of pneumococcal diseases in Canadian children. The epidemiological data and the economic cost of these diseases are crucial elements in evaluating the relevance of a vaccination program.

METHODS

Using provincial databases, ad hoc surveys and published data, age-specific incidence rates of pneumococcal infections were estimated in a cohort of 340,000 children between six months and nine years of age. The costs of these diseases to the health system and to families were also evaluated using data from Quebec and Manitoba.

RESULTS

Cumulative risks were one in 5000 for pneumococcal meningitis, one in 500 for bacteremia and one in 20 for pneumonia, leading to 16 deaths in the cohort. About 262,000 otitis media episodes and 32,000 cases of myringotomy with ventilation tube insertion were attributable to Streptococcus pneumoniae. Societal costs were estimated at $125 million, of which 32% was borne by the health system and 68% was borne by families. Invasive infections represented only 2% of total costs, while 84% were generated by otitis media.

CONCLUSION

Pneumococcal infections represent a significant burden for Canadian children and society that could be significantly reduced through immunization.

Rapid diagnosis of Mycoplasma pneumoniae by polymerase chain reaction in community-acquired lower respiratory tract infections

Two hundred children hospitalized for community-acquired lower respiratory tract infections (LRTIs) were investigated for Mycoplasma pneumoniae employing serological tests and a P1 adhesin gene-based polymerase chain reaction assay (PCR) on nasopharyngeal aspirates. Serological evidence of M. pneumoniae infection was observed in 68 (34%) patients and PCR was positive in 20 (10%) children. Together PCR and/or enzyme immuno assay detected M. pneumoniae in 71(35.5%) children. Our data underline the role of M. pneumoniae in Indian children with community-acquired LRTIs even in children aged < 24 months.

Viral pneumonia

About 200 million cases of viral community-acquired pneumonia occur every year-100 million in children and 100 million in adults. Molecular diagnostic tests have greatly increased our understanding of the role of viruses in pneumonia, and findings indicate that the incidence of viral pneumonia has been underestimated. In children, respiratory syncytial virus, rhinovirus, human metapneumovirus, human bocavirus, and parainfluenza viruses are the agents identified most frequently in both developed and developing countries. Dual viral infections are common, and a third of children have evidence of viral-bacterial co-infection. In adults, viruses are the putative causative agents in a third of cases of community-acquired pneumonia, in particular influenza viruses, rhinoviruses, and coronaviruses. Bacteria continue to have a predominant role in adults with pneumonia. Presence of viral epidemics in the community, patient's age, speed of onset of illness, symptoms, biomarkers, radiographic changes, and response to treatment can help differentiate viral from bacterial pneumonia. However, no clinical algorithm exists that will distinguish clearly the cause of pneumonia. No clear consensus has been reached about whether patients with obvious viral community-acquired pneumonia need to be treated with antibiotics. Apart from neuraminidase inhibitors for pneumonia caused by influenza viruses, there is no clear role for use of specific antivirals to treat viral community-acquired pneumonia. Influenza vaccines are the only available specific preventive measures. Further studies are needed to better understand the cause and pathogenesis of community-acquired pneumonia. Furthermore, regional differences in cause of pneumonia should be investigated, in particular to obtain more data from developing countries.

Asthma and pneumonia

Chest pain remains a common complaint among children seeking care in the United States. Asthma and lower respiratory tract infections such as pneumonia can be significant causes of chest pain. Children with chest pain caused by either of these pulmonary etiologies generally present with associated respiratory symptoms, including cough, wheezing, tachypnea, respiratory distress, and/or fever. Although analgesic medications can improve chest pain associated with pulmonary pathologies, the mainstay of therapy is to treat the underlying etiology; this includes bronchodilator and/or steroid medications in children with asthma and appropriate antibacterial administration in children with suspicions of bacterial pneumonia. The chest pain generally resolves along with the resolution of other respiratory symptoms.

Variations in the management of pneumonia in pediatric emergency departments: compliance with the guidelines

OBJECTIVE

We sought to assess compliance with evidence-based guidelines for the management of pediatric pneumonia, including the variations in tests ordered and antimicrobials prescribed. Our primary hypothesis was that compliance with the treatment recommendations from the most current guidelines would be low for antimicrobial prescriptions.

METHODS

We conducted a chart review at the Children's Hospital in London, Ont., to assess variation in the management of pediatric pneumonia. All patients aged 3 months to 18 years seen at the pediatric emergency department between Apr. 1, 2006, and Mar. 31, 2007, with a diagnosis of pneumonia were eligible for inclusion in the study.

RESULTS

Compliance with management guidelines was 59.7% (95% confidence interval [CI] 53%-66%, n = 211) in children 5-18 years old and 83.0% (95% CI 80%-86%, n = 605) in children 3 months to 5 years old. Significant variation existed in the choice of antimicrobial agent for children with pneumonia, with nonrecommended agents frequently prescribed.

CONCLUSION

Significant variation existed in the management of pediatric pneumonia, and adherence to guidelines was low for the group of patients aged 5-18 years. Future studies should attempt to provide guidance to distinguish between viral and bacterial etiology to allow judicious use of antimicrobials.

Etiology of community-acquired pneumonia in hospitalized children based on WHO clinical guidelines

Community-acquired pneumonia (CAP) is a major cause of death in developing countries and of morbidity in developed countries. The objective of the study was to define the causative agents among children hospitalized for CAP defined by WHO guidelines and to correlate etiology with clinical severity and surrogate markers. Investigations included an extensive etiological workup. A potential causative agent was detected in 86% of the 99 enrolled patients, with evidence of bacterial (53%), viral (67%), and mixed (33%) infections. Streptococcus pneumoniae was accounted for in 46% of CAP. Dehydration was the only clinical sign associated with bacterial pneumonia. CRP and PCT were significantly higher in bacterial infections. Increasing the number of diagnostic tests identifies potential causes of CAP in up to 86% of children, indicating a high prevalence of viruses and frequent co-infections. The high proportion of pneumococcal infections re-emphasizes the importance of pneumococcal immunization.

Comparison of oral amoxicillin and intravenous benzyl penicillin for community acquired pneumonia in children (PIVOT trial): a multicentre pragmatic randomised controlled equivalence trial

OBJECTIVE

To ascertain whether therapeutic equivalence exists for the treatment of paediatric community acquired pneumonia by the oral and intravenous (IV) routes.

METHODS

A multicentre pragmatic randomised controlled non-blinded equivalence trial was undertaken in eight paediatric centres in England (district general and tertiary hospitals). Equivalence was defined as no more than a 20% difference between treatments of the proportion meeting the primary outcome measure at any time. 246 children who required admission to hospital and had fever, respiratory symptoms or signs and radiologically confirmed pneumonia were included in the study. Exclusion criteria were wheeze, oxygen saturations <85% in air, shock requiring >20 ml/kg fluid resuscitation, immunodeficiency, pleural effusion at presentation requiring drainage, chronic lung condition (excluding asthma), penicillin allergy and age <6 months. The patients were randomised to receive oral amoxicillin for 7 days (n = 126) or IV benzyl penicillin (n = 120). Children in the IV group were changed to oral amoxicillin after a median of six IV doses and received 7 days of antibiotics in total. The predefined primary outcome measure was time for the temperature to be <38 degrees C for 24 continuous hours and oxygen requirement to cease. Secondary outcomes were time in hospital, complications, duration of oxygen requirement and time to resolution of illness.

RESULTS

Oral amoxicillin and IV benzyl penicillin were shown to be equivalent. Median time for temperature to settle was 1.3 days in both groups (p<0.001 for equivalence). Three children in the oral group were changed to IV antibiotics and seven children in the IV group were changed to different IV antibiotics. Median time to complete resolution of symptoms was 9 days in both groups.

CONCLUSION

Oral amoxicillin is effective for most children admitted to hospital with pneumonia (all but those with the most severe disease who were excluded from this study). Prior to this study, the British Thoracic Society guidelines on childhood pneumonia could not draw on evidence to address this issue. This will spare children and their families the trauma and pain of cannulation, and children will spend less time in hospital.

Effective treatment strategies for paediatric community-acquired pneumonia

Pneumonia is the leading cause of death in children under 5 years of age worldwide and a cause of morbidity in a considerable number of children. A number of studies have sought to identify the ideal choice of antibiotics, route of administration and optimum duration of treatment based on the most likely aetiological agents. Emerging bacterial resistance to antibiotics is also an important consideration in treatment. However, inconsistent clinical and radiological definitions of pneumonia make comparison between studies difficult. There is also a lack of well designed adequately powered randomised controlled trials. This review describes the difficulties encountered in diagnosing community-acquired pneumonia, aetiology, treatment strategies with recommendations and highlights areas for further research.

Evaluation of the utility of radiography in acute bronchiolitis

OBJECTIVES

To determine the proportion of radiographs inconsistent with bronchiolitis in children with typical presentation of bronchiolitis and to compare rates of intended antibiotic therapy before radiography versus those given antibiotics after radiography.

STUDY DESIGN

We conducted a prospective cohort study in a pediatric emergency department of 265 infants aged 2 to 23 months with radiographs showing either airway disease only (simple bronchiolitis), airway and airspace disease (complex bronchiolitis), and inconsistent diagnoses (eg, lobar consolidation).

RESULTS

The rate of inconsistent radiographs was 2 of 265 cases (0.75%; 95% CI 0-1.8). A total of 246 children (92.8%) had simple radiographs, and 17 radiographs (6.9%) were complex. To identify 1 inconsistent and 1 complex radiograph requires imaging 133 and 15 children, respectively. Of 148 infants with oxygen saturation >92% and a respiratory disease assessment score <10 of 17 points, 143 (96.6%) had a simple radiograph, compared with 102 of 117 infants (87.2%) with higher scores or lower saturation (odds ratio, 3.9; 95% CI, 1.3-14.3). Seven infants (2.6%) were identified for antibiotics pre-radiography; 39 infants (14.7%) received antibiotics post-radiography (95% CI, 8-16).

CONCLUSIONS

Infants with typical bronchiolitis do not need imaging because it is almost always consistent with bronchiolitis. Risk of airspace disease appears particularly low in children with saturation higher than 92% and mild to moderate distress.

Detection of human coronavirus NL63, human metapneumovirus and respiratory syncytial virus in children with respiratory tract infections in south-west Sweden

Two recently detected viruses, human metapneumovirus (hMPV) and coronavirus NL63 (HCoV‐NL63), have been associated with acute respiratory tract infections, particularly in young children. This study investigated the frequency of hMPV and HCoV‐NL63 infections in Swedish children by screening 221 nasopharyngeal aspirates, collected between November 2003 and May 2005, from 212 children attending the paediatric department of a county hospital in Sweden or submitted from local general practitioners. The samples were originally submitted to be tested for respiratory syncytial virus (RSV), and were examined retrospectively for hMPV and HCoV‐NL63 by RT‐PCR. Of the 212 patients, 101 were positive for RSV (48%), 22 (10%) were positive for hMPV, and 12 (6%) were positive for HCoV‐NL63. The frequency of HCoV‐NL63 infection increased from 1% in 2003–2004 to 10% in 2004–2005. Sequence analysis of parts of the coronavirus genomes showed considerable similarity to the HCoV‐NL63 prototype sequence. The study demonstrated that HCoV‐NL63 and hMPV occur in south‐west Sweden with essentially the same frequency, seasonal distribution and clinical characteristics as have been reported in other countries.

Role of Mycoplasma pneumoniae and Chlamydia pneumoniae in children with community-acquired pneumonia in Istanbul, Turkey

BACKGROUND

To investigate the role of Mycoplasma pneumoniae and Chlamydia pneumoniae infection in pediatric pneumonia, in Istanbul, Turkey, we conducted a prospective study covering all the children between 2 months and 15 years hospitalized for community-acquired pneumonia.

METHODS

A total of 140 children (85 males, median age 2.5 years) with community-acquired pneumonia were enrolled. Acute and convalescent sera were tested for IgM and IgG antibodies to M. pneumoniae (enzyme-linked immunosorbent assay, Serion ELISA classic) and for IgM and IgG antibodies to C. pneumoniae (microimmunofluorescence, Savyon, Israel).

RESULTS

Mycoplasma pneumoniae infection was diagnosed in 38 patients (27%) and C. pneumoniae infection in 7 (5%). In 2 children M. pneumoniae and C. pneumoniae co infection was observed. The average age of the M. pneumoniae cases was 5.3 years and that of the C. pneumoniae was 1.5 years. The average age of pneumonia cases caused by other pathogens was 3.4 years (p<0.05). No significant difference was observed in clinical onset, signs, symptoms and laboratory parameters in children with M. pneumoniae and C. pneumoniae infection and in those without M. pneumoniae and C. pneumoniae infection.

CONCLUSIONS

The results of this study suggest a remarkable role for M. pneumoniae and C. pneumoniae in childhood community-acquired pneumonia, and the knowledge of the true prevalence of these two types of infections discovered in the community might lead to modifications in the present empirical treatment of bacterial pneumonia.

Influenza pneumonia

BACKGROUND

Influenza and pneumonia are common childhood illnesses, but few studies have been conducted on influenza-related pneumonia in children. The aim of this study was to describe the frequency and characteristics of laboratory-documented and radiologically detected influenza pneumonia in children.

METHODS

This study involved children treated at the Department of Pediatrics, Turku University Hospital, from 1980 through 2003. Influenza A or B infection was documented with the use of antigen detection from nasopharyngeal aspirates. Children with chest radiographs obtained during influenza episodes were identified. Chest radiographs were reevaluated by a pediatric radiologist for verification of pneumonic infiltrates. Clinical and laboratory data were collected from medical records.

RESULTS

Pneumonia was detected in 134 (14%) of 936 children with influenza infection. The most frequent signs of influenza pneumonia were fever and cough. Of these children, 47% had no specific clinical signs or symptoms suggesting pneumonia. White blood cell count was <15 x 10/L in 89% and serum C-reactive protein concentration <80 mg/L in 85% of the children. One-half of the children had solely interstitial infiltrates, one-fourth solely alveolar and one- fourth both alveolar and interstitial infiltrates on the chest radiograph. The hospitalization rate was 68%, and the median duration of hospitalization was 2 days. Complicated pneumonias were rare, and mortality was low (0.7%).

CONCLUSIONS

Pneumonia is detected in a minority of children treated for influenza at a tertiary center. Unlike in adults, influenza pneumonia in children is usually a benign illness, and the mortality is low.

Aetiology of community-acquired pneumonia: serological results of a paediatric survey

Serological methods are routinely used in the diagnosis of viral and atypical bacterial respiratory infections. Recently, they have also been applied to typical bacteria, such as Streptococcus pneumoniae. The aim of this study was to determine the aetiology of paediatric community-acquired pneumonia (CAP) in both ambulatory and hospitalized patients, by using antibody assays. During a 15-month prospective surveillance, paired sera were studied for antibodies to 14 microbes in 101 children with symptoms of acute infection and infiltrates compatible with pneumonia on chest radiographs. A potential causative agent was detected in 66 (65%) patients. Evidence of bacterial, viral and mixed viral-bacterial infection was demonstrated in 44%, 42% and 20% of the CAP cases, respectively. The most commonly found agents included Mycoplasma pneumoniae (27%), Pneumococcus (18%) and respiratory syncytial virus (17%). Human metapneumovirus (hMPV) was detected in 5 (5%) children. Pneumococcal infections were evenly distributed among the age groups studied. Our results confirm the role of S. pneumoniae in paediatric CAP at all ages, those of M. pneumoniae at >2 y of age and emphasize the emerging role of hMPV. The high proportion of mixed viral-bacterial infections highlights the need to treat all children with CAP with antibiotics.

Diagnosis of parapneumonic pleural effusion by polymerase chain reaction in children

PURPOSE

Most pleural effusions are associated with bacterial pneumonia, and the identification of the pathogen will assist the therapeutic decision. A specific method that is not affected by previous antibiotic therapy is sought to detect the main causative agents of pneumonia in infants and children (Streptococcus pneumoniae, Haemophilus influenzae, and Staphylococcus aureus). The aim of the present study was to compare the polymerase chain reaction (PCR) technique with standard culture methods in identifying bacterial infections in infants' and children's pleural effusion.

METHODS

Samples obtained from pediatric patients (n = 37) with a diagnosis of pneumonia associated to pleural effusion, submitted to thoracentesis, were analyzed by PCR with specific primers.

RESULTS

The PCR technique identified the presence of bacterial infection in a larger proportion (95.2%) than the standard culture method (33.3%) on complicated pleural effusion samples. The microorganism detection on uncomplicated pleural effusion samples was positive only by the PCR method (31.3%). The frequencies of microorganisms identified on complicated pleural effusion were 57.1% of all patients for methicillin-resistant Staphylococcus; 52.4%, S pneumoniae; 28.6%, S aureus; and 23.8%, H influenzae. The previous use of antibiotics interferes with standard culture method, but it did not interfere with the PCR results.

CONCLUSIONS

The molecular diagnosis by PCR method could improve the etiologic diagnosis and might help to guide the treatment of parapneumonic effusion in children.

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.

Can chest X-ray predict pneumonia severity?

Predictors of the severity of pneumonia have not been thoroughly evaluated among children in developed countries. We investigate whether chest radiographic findings could be used as predictors of severity of childhood pneumonia. The study included 167 children, aged more than 12 months, hospitalized in our department during a 4-year period with unilateral lobar or segmental pneumonia. The durations of fever and of hospitalization were considered indicators of severity of the disease. The size of the consolidation and its location in the left hemithorax were independently associated with severity of the disease. Univariate analysis showed that the mean duration of fever and of hospitalization as well as the prevalence of pleural effusion was significantly higher among children with left-sided pneumonia. A multiple logistic regression analysis revealed that only the presence of pleural effusion was significantly more likely in left-sided pneumonia (odds ratio, 2.65; 95% confidence interval, 1.09-6.47; P = 0.031). We conclude that the size of consolidation and the side of its location can be used as predictors of severity of pneumonia, with left-sided pneumonia running a more severe course, possibly due to increased risk for the development of pleurisy.

Respiratory viruses seasonality in children under five years of age in Buenos Aires, Argentina: a five-year analysis

OBJECTIVES

During the winter months there is a remarkable increase in paediatric hospitalisations due to viral acute lower respiratory infections (ALRI). We aimed to perform a five-year retrospective analysis (1998-2002) of ALRI viral aetiology in children under 5 years of age admitted to public hospitals in Buenos Aires city to evaluate its seasonality.

MATERIALS AND METHODS

Nasopharyngeal aspirates (NPA) were analysed by indirect immunofluorescence to determine viral aetiology. A Spearman's rank correlation test between meteorological parameters and viral frequencies was performed.

RESULTS

Viruses were identified in 6083 (32.8%) of 18,561 NPA tested. Among the former 4796 (78.8%) were RSV, 508 (8.3%) IA, 473 (7.8%) AV, 293 (4.8%) PIV and 13 (0.2%) IB. RSV and IA peaked during the coldest and dampest months, whereas PIV did so in early spring and AV lasted throughout the year. For RSV and IA an inverse correlation with mean monthly temperature (r = -0.9 and r = -0.87, respectively, p<0.0001) and solar UVB radiation (r = -0.92 and r = -0.80, respectively, p<0.0001) was detected, while it was positive when relative humidity was considered (r = 0.6, p<0.0001 and r = 0.47, p=0.0068, respectively).

CONCLUSIONS

This study highlights the seasonal variation of ALRI and allows the implementation of adequate healthcare strategies and practice guidelines.

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.

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.

Adenovirus infection in hospitalized immunocompetent children

This study investigated the clinical features of immunocompetent children with adenovirus infection requiring hospitalization. The files of 78 children (mean age 17 +/- 10 months) with community-acquired adenovirus infection admitted over a 2-year period were reviewed. The children were referred after 5.7 +/- 3.4 days of illness, all with fever (mean peak 39.8 +/- 0.8 degrees C). Temperature normalized after 3.5 +/- 2 days. Duration of hospitalization (mean, 7.0 +/- 3.9 days) correlated with lethargy, lung crackles, cracked lips, hypoxia, impaired liver tests, and high serum lactic dehydrogenase (LDH) concentration at admission. Serum LDH concentrations and hypoxemia predicted 70% of the variance in hospital stay. All patients recovered. Adenovirus infection may cause considerable morbidity, even in immunocompetent children. Disease severity, defined by duration of hospitalization, correlates with serum LDH concentrations and oxygen saturation at admission.

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.

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.

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 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.

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.

Mixed microbial aetiology of community-acquired pneumonia in children

Seven paediatric studies on community-acquired pneumonia with serological methods for both viruses and bacteria have been published, allowing the evaluation of concomitant multiple etiological findings. In these studies, dual viral infection has been present in 0-14%, dual bacterial infection likewise in 0-14%, and mixed viral-bacterial infection in 3-30% of the pneumonia cases. The results confirm former clinical observations that respiratory viruses often pave the way for airway-colonising bacteria. The measured frequency of multiple infections has been dependent on the available test panel, mainly on the tests used for pneumococcal aetiology. Mixed viral-bacterial infections have been especially common in young children under 2 years of age, reflecting the high frequency of respiratory syncytial virus infections and their tendency to induce bacterial co-infections. No microbe-specific viral-bacterial associations have been demonstrated. The clinical implications of mixed viral-bacterial infections, compared with viral infections alone or bacterial infections alone, have so far remained unresolved. Current guidelines recommend antibiotic therapy for all community-acquired pneumonia cases in children.