Pneumonia in childhood: etiology and response to antimicrobial therapy

An approach to the child with a wet cough

When children have a wet cough, it suggests the presence of secretions in their airways. This often has an infectious aetiology which is usually a self-limiting viral infection requiring no investigation or treatment. In those with acute wet cough it is, however, important to identify features suggestive of community acquired pneumonia or an inhaled foreign body as these causes require specific management. When there is chronic wet cough, the most common diagnoses are protracted bacterial bronchitis (PBB) and bronchiectasis. The relationship between these two conditions is complex as the development of bronchiectasis manifests as a clinical continuum in which the early features of which are indistinguishable from PBB. It is therefore important to identify PBB and chronic cough endotypes which are associated with an increased risk of bronchiectasis. This article offers a pragmatic approach to the investigation and treatment of children with wet cough. It is hoped this will limit unnecessary investigations whist aiding the prompt diagnosis of conditions needing treatment to reduce symptom burden and prevent further lung damage.

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.

Diagnostic value of bronchoalveolar lavage in children with nonresponding community-acquired pneumonia

BACKGROUND

Community-acquired pneumonia (CAP) is a common cause of morbidity and mortality in hospitalized children. In CAP, causative agents are seldom identified using noninvasive diagnostic procedures. For those children not responding to empiric antibiotic therapy, it is vital to identify the causative pathogens for further management.

METHODS

We aimed to determine the usefulness of identifying the causative agents by bronchoalveolar lavage (BAL) in hospitalized children with nonresponding CAP. Ninety children hospitalized for CAP and treated with empiric antibiotics but having persistent fever ≥48 hours were enrolled, and their BAL data were retrospectively reviewed.

RESULTS

Aerobic bacteria were isolated from 38 (42%) of 90 cultures, and anaerobic bacteria were isolated from eight (24%) of 33 cultures. The bacteria isolated most frequently were Streptococcus viridians (26.3%), Pseudomonas aeruginosa (23.7%), and Staphylococcus aureus (15.8%). Streptococcus pneumoniae was isolated from the BALs of only two children, and Haemophilus influenzae from none. For positive aerobic culture results, BAL results guided modifications of antibiotic regimens in 21 episodes (21 of 38, 55.3%).

CONCLUSION

BAL results guided a change of antimicrobials in 55% of children with positive aerobic cultures (29% of all children in the study) and contributed to a high rate of successful therapy.

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.

A molecular epidemiology survey of respiratory adenoviruses circulating in children residing in Southern Palestine

A molecular epidemiology survey was performed in order to establish and document the respiratory adenovirus pathogen profiles among children in Southern Palestine. Three hundred and thirty-eight hospitalized pediatric cases with adenovirus-associated respiratory tract infections were analyzed. Forty four cases out of the 338 were evaluated in more detail for the adenoviruses types present. All of the children resided in Southern Palestine, that is, in city, village and refugee camp environments within the districts of Hebron and Bethlehem. Human adenoviruses circulated throughout 2005–2010, with major outbreaks occurring in the spring months. A larger percent of the children diagnosed with adenoviral infections were male infants. DNA sequence analysis of the hexon genes from 44 samples revealed that several distinct adenovirus types circulated in the region; these were HAdV-C1, HAdV-C2, HAdV-B3 and HAdV-C5. However, not all of these types were detected within each year. This is the first study ever conducted in Palestine of the genetic epidemiology of respiratory adenovirus infections.

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.

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.

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.

Prediction of delayed recovery from pediatric community-acquired pneumonia

Background

If children with community-acquired pneumonia (CAP) do not recover within 48 hours after starting antibiotic therapy, complications are possible and a checkup must be ensured.

Aim of the present study was to evaluate the improvement of pediatric CAP, within 48 hours after starting therapy, in relation to age, etiology, clinical/laboratory characteristics and selected antibiotics.

Methods

Ninety-four children were treated for radiologically confirmed CAP, 64 by oral amoxicillin, 23 by intravenous ampicillin and 7 by other antibiotics. The etiology of CAP was studied by serology, data on more than 20 clinical characteristics were collected retrospectively, and antibiotics were selected on clinical grounds.

Results

After starting of antibiotics, the mean duration of fever was higher in children ≥5 than <2 or 2-4 years of age (p = 0.003). Fever continued >48 hours in 4 (4.3%) children and 2 additional children had empyema. Clinical, radiological and laboratory characteristics and serological findings were not significantly associated with the duration of fever. Fever continued >24 hours in 1 (4.8%) child treated with ampicillin and in 2 (8%) inpatients compared with 19 (28.8%) children treated with amoxicillin (p = 0.007) and 23 (33%) outpatients (p = 0.0012), respectively.

Conclusions

Respiratory rate and erythrocyte sedimentation rates were associated with rapid decrease of fever. Anyway, none of the reported characteristics was able to predict treatment failures or delayed fever decrease in children suffering from CAP.

Community-acquired Moraxella catarrhalis pneumonia in previously healthy children

BACKGROUND

The aim of this study was to determine if Moraxella catarrhalis is a common cause of community acquired pneumonia in children with no chronic medical problems. A secondary goal was to describe the clinical features of children with M. catarrhalis pneumonia.

METHODS

A systematic literature search was conducted for (i) case series of pediatric community-acquired pneumonia (CAP) where one or more diagnostic tests for M. catarrhalis were applied to all cases and (ii) case reports of previously healthy children with proven M. catarrhalis pneumonia.

RESULTS

There were nine case series describing a total of 1,500 children with CAP. The number of children tested and yield was as follows: blood cultures 0/402 (0%); sputum cultures 15/157 (10%); nasopharyngeal, or postnasal cultures 129/521 (25%); sputum or nasopharyngeal cultures 0/74 (0%) (one study allowed either); nucleic acid amplification testing 2/100 (2%); serology 30/976 (3%). There were eight case reports of CAP with M. catarrhalis in previously well children. Children were ages 3 weeks to 7 years of age (median 14 months). Six of 8 (75%) children required mechanical ventilation. All survived.

CONCLUSION

It is common to detect M. catarrhalis in upper respiratory secretions in children with pneumonia, but bacteremia or seroconversion is rare. There are only eight well-documented case reports CAP due to M. catarrhalis in previously well children, with there being no distinctive features in the eight cases described to date. This organism is likely a rare cause of CAP in previously healthy children.

Empiric antibiotics are justified for infants with respiratory syncytial virus lower respiratory tract infection presenting with respiratory failure: a prospective study and evidence review

OBJECTIVE

Although some studies indicate a low risk of serious bacterial infection in infants with respiratory syncytial virus (RSV), these studies focused on patients who did not progress to respiratory failure. We hypothesized the composite diagnosis of concomitant bacterial pneumonia (CBP) is common in lower risk infants with RSV who present in respiratory failure. The aim of the study was to investigate the incidence of CBP in low-risk infants mechanically ventilated for RSV respiratory failure and to compare the results with other studies searched for in MEDLINE.

DESIGN

Prospective, descriptive study, and literature review. Two MEDLINE searches were done using the terms 1) respiratory syncytial virus (RSV) and pneumonia, and 2) RSV, pneumonia, and antibiotics.

SETTING

Tertiary pediatric intensive care unit (PICU) in the Northeast United States.

PATIENTS

We prospectively enrolled 23 infants admitted to our PICU with RSV infection and respiratory failure over a 27-month period.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

All infants were intubated on arrival or soon thereafter; 22 had diagnostic tracheal aspiration performed, and 20 had blood cultures obtained shortly after admission. All had white blood cell count, temperature measured, and chest radiograph. Only one had antibiotics before culture. The length of mechanical ventilation, PICU course, and hospital stay were recorded.The primary outcome variable was the composite diagnosis of CBP as determined by the following criteria: 1) isolation of pathogenic bacteria from a tracheal aspirate, 2) blood culture, 3) chest radiograph, 4) temperature abnormality, and 5) peripheral white blood cell count. In our study, 7 infants met four criteria (probable pneumonia); 6 met three criteria (possible pneumonia); and 10 infants met less than three criteria. By tracheal aspirate criteria alone, 9 of 23 (39%) had probable pneumonia and 9 of 23 had possible pneumonia by previously published criteria. The mean length of mechanical ventilation for 7 infants who met four criteria was 10 +/- 2.7 (sem) days; for 6 infants who met three criteria, 10.5 +/- 2.1 days; and for infants who met less than three criteria 7.4 +/- 0.9 days. The mean PICU stay was 14.3 +/- 3.6 days for infants who met four criteria; 14.3 +/- 3.0 days for infants who met three criteria; and 9.9 +/- 1.4 days for infants who met less than three criteria. The mean hospital stay was 16.3 +/- 3.4 for infants who met four criteria; 18.7 +/- 2.8 days for infants who met three criteria; and 24.8 +/- 9.6 days for infants who met less than three criteria. These differences were not statistically significant. A MEDLINE search was performed using the terms 1) RSV and pneumonia, and 2) RSV, pneumonia, and antibiotics.

CONCLUSIONS

While the small size of this study does not permit definitive conclusions, these data, in combination with other data from the literature, suggest that composite evidence of bacterial pneumonia in otherwise low-risk infants with RSV presenting with respiratory failure is 20% or higher and the use of empirical antibiotics for 24 to 48 hrs pending culture results may be justified and could be used until CBP is excluded.

Mycoplasma pneumoniae infection associated with pancytopenia: a case report

Immune hemolytic anemia is a rare condition in childhood. Cold agglutinins have been implicated in the etiology of the hemolysis and frequently observed during Mycoplasma pneumoniae infections. We present here a case of cold agglutinin-related hemolytic anemia, thrombocytopenia, and leukopenia secondary to M. pneumoniae associated pneumonia. It is suggested that even though very rare, M. pneumoniae infection should be considered as the underlying disease in a patient presenting with pancytopenia.

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.

Radiographic pneumonia in young, highly febrile children with leukocytosis before and after universal conjugate pneumococcal vaccination

OBJECTIVES

Studies before the introduction of conjugate pneumococcal vaccine demonstrated a high rate of radiographic pneumonia among highly febrile young children with leukocytosis and no other identified source of infection. We sought to evaluate the impact of universal vaccination with Prevnar (pneumococcal conjugate vaccine [PCV]) on the incidence and characteristics of occult and nonoccult radiographic pneumonia among these children.

METHODS

Retrospective cohort study of children younger than 5 years seen in an urban pediatric emergency department with temperature 39 degrees C or higher, white blood cell count 20,000/microL or higher, and chest radiograph performed. Pneumonia was defined as focal infiltrate or consolidation on chest radiograph as read by an attending radiologist. Occult pneumonia was defined as radiographic pneumonia in the absence of lower respiratory tract signs or cough.

RESULTS

Before universal pneumococcal vaccination, radiographic pneumonia was found in 190 (21%) of 889 (95% confidence interval [CI], 19-24) eligible children compared with 61 (18%) of 335 (95% CI: 14, 23) eligible children after universal vaccination (P = 0.27). Occult pneumonia was identified in 61 (15%) of 404 (95% CI, 12-19) pre-PCV compared with 13 (9%) of 147 (95% CI, 5-15) post-PCV (P = 0.07). In children younger than 2 years, radiographic pneumonia was identified in 121 (17%) of 709 (95% CI, 14-20) pre-PCV and 26 (10%) of 254 (95% CI, 7-15) post-PCV (P = 0.01).

CONCLUSIONS

Clinicians should continue to consider chest radiography in young highly febrile children with leukocytosis and no other identified source of infection.

Management of community-acquired pneumonia in children

Community-acquired pneumonia (CAP) is a significant cause of childhood morbidity and mortality worldwide. Viral etiology is most common in young children and decreases with age. Streptococcus pneumoniae is the single most common bacterial cause across all age groups. Atypical organisms present similarly across all age groups and may be more common than previously recognized.A bacterial pneumonia should be considered in children presenting with fever >38.5 degrees C, tachypnea, and chest recession. Oxygen therapy is life saving and should be given when oxygen saturation is <92%. For non-severe pneumonia, oral amoxicillin is the antibacterial of choice with low failure rates reported. Severely ill children are traditionally treated with parenteral antibacterials. Penicillin non-susceptible S. pneumoniae prevalence rates are increasing and have been linked to community antibacterial prescribing. Most pneumococci remain sensitive to high-dose penicillin-based antibacterials but macrolide resistance is also a problem in some communities. However, primary combination treatment with macrolides is indicated in areas where there is a high prevalence of atypical organisms. The most common complications in CAP are parapneumonic effusions and empyema. The use of ultrasonography combined with intercostal drainage augmented with the use of fibrinolytic therapy has significantly reduced the morbidity associated with these complications. There is increasing evidence that a preventative strategy with the 7-valent pneumococcal conjugate vaccine (PCV-7) results in a significant fall in CAP in early childhood.

[Respiratory syncytial virus in hospitalized children. A 3-year study]

OBJECTIVE

To assess the prevalence of respiratory syncytial virus (RSV) and other important respiratory viruses in children hospitalized in a pediatric hospital in Paris (France) during a 3-year period (2001 to 2004).

PATIENTS AND METHODS

The study included all patients aged 8 days to 16 years admitted from the community through emergency department with bronchiolitis, pneumonia, upper respiratory tract infection, asthma or acute isolated fever and who had nasopharyngeal samples taken for viral identification by immunofluorescence (RSV, influenza, para-influenza, and adenoviruses).

RESULTS

A virus was found in 464 of 1208 patients with samples taken. RSV was identified in 375 patients, 74% of them younger than 6 months and diagnosed with bronchiolitis. RSV was isolated more often than any other virus, overall and for all diagnoses except "isolated fever," for which influenza was more frequent. In patients aged 24 months or older, influenza and RSV were identified at the same frequency. Overall, influenza virus was found in 53 patients, adenoviruses in 24 and para-influenza viruses in 11.

CONCLUSION

RSV was the respiratory virus isolated most often, even in older children, during this 3-year study. The relative rarity of hospitalizations due to para-influenza viruses is characteristic of this area, compared with some other countries.

Development of parapneumonic empyema in children

AIM

The aim of the study was to find clinical predictors for parapneumonic empyema in children.

METHODS

Thirty-seven children treated for parapneumonic empyema at the Department of Pediatrics, Turku University Hospital, were retrospectively evaluated. Two distinct comparison groups of children with uncomplicated community-acquired pneumonia with alveolar consolidation (n = 37 in both groups) were included. Clinical and laboratory data on admission as well as fever kinetics and inflammatory markers during hospitalization were analyzed.

RESULTS

In a multivariate analysis, a history of prolonged fever, tachypnoea and pain on abdominal palpation on admission were the most significant clinical predictors for empyema. On admission, serum C-reactive protein levels were higher among children with empyema than among those with uncomplicated pneumonia (means, 234 mg/L vs. 178 mg/L; p = 0.037). During hospitalization, prolonged fever and persistence of high serum C-reactive protein levels were associated with empyema. At the initial evaluation, pleural fluid was not reported in 35% of children with empyema.

CONCLUSIONS

Early recognition of developing empyema is challenging. Children with pneumonia presenting with prolonged fever, tachypnoea, pain on abdominal palpation and high serum C-reactive protein levels are at risk for parapneumonic empyema.

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.

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.

[Study of the clinical and epidemiological characteristics of respiratory infections caused by adenovirus in a pediatric population (1997-2003)]

INTRODUCTION

Infections due to adenoviruses are highly prevalent in pediatric patients. Because the clinical manifestations of the respiratory infections caused by adenoviruses are indistinguishable from those caused by other respiratory viruses, virological methods are required to establish their etiology. We present a retrospective study of the clinical and virological characteristics of patients with isolation of adenovirus in respiratory samples.

MATERIAL AND METHODS

From 1997 to 2003 we analyzed 5,746 respiratory samples from pediatric patients (< 15 years old), of which 2,122 (36.9 %) were considered positive. The adenoviruses were isolated in the Hep-2 cell line culture by the shell vial method.

RESULTS

Adenovirus was isolated in 100 clinical samples (4.7 % of all positive samples and 1.7 % of all samples studied) in a group of pediatric patients with a mean age of 14 months. The clinical diagnoses of patients were bronchiolitis (61 %), pneumonia (10 %), pertussis-like syndrome (16 %) and asthmatic crisis (11 %). Adenovirus infections mainly presented between December and March. Seventy-two percent of patients had a history of other viral respiratory tract infections and/or bronchial asthma. None of the patients had clinical conjunctivitis and only five patients had diarrhea due to adenoviruses. Seventy percent of the patients received artificial feeding and 30 % were breast-fed. Ninety percent of the patients were hospitalized and treatment mainly consisted of bronchodilator agents and antibiotics.

CONCLUSIONS

Respiratory tract infections caused by adenoviruses mainly affected patients aged less than 14 months, in the first four months of the year, and with clinical manifestations of bronchiolitis or pneumonia without conjunctivitis. Clinically, these infections are difficult to differentiate from other viral respiratory infections.

Mycoplasma pneumoniae and its role as a human pathogen

Mycoplasma pneumoniae is a unique bacterium that does not always receive the attention it merits considering the number of illnesses it causes and the degree of morbidity associated with it in both children and adults. Serious infections requiring hospitalization, while rare, occur in both adults and children and may involve multiple organ systems. The severity of disease appears to be related to the degree to which the host immune response reacts to the infection. Extrapulmonary complications involving all of the major organ systems can occur in association with M. pneumoniae infection as a result of direct invasion and/or autoimmune response. The extrapulmonary manifestations are sometimes of greater severity and clinical importance than the primary respiratory infection. Evidence for this organism's contributory role in chronic lung conditions such as asthma is accumulating. Effective management of M. pneumoniae infections can usually be achieved with macrolides, tetracyclines, or fluoroquinolones. As more is learned about the pathogenesis and immune response elicited by M. pneumoniae, improvement in methods for diagnosis and prevention of disease due to this organism may occur.

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.

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.

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.

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.

Procalcitonin, C-reactive protein and leukocyte count in children with lower respiratory tract infection

BACKGROUND

Lower respiratory tract infection is the most common infection leading to unnecessary antibiotic treatment in children. Etiologic diagnosis is not immediately achieved, and the pathogen remains unidentified in a large number of cases. Neither clinical nor laboratory factors allow for a rapid distinction between bacterial and viral etiology. The aim of our study was to evaluate the reliability of procalcitonin (PCT), C-reactive protein (CRP) and leukocyte count in distinguishing pneumococcal, atypical and viral lower respiratory tract infection.

METHODS

PCT, CRP and leukocyte count were measured in children with microbiologically documented diagnoses of lower respiratory tract infection. The results were compared of children with pneumococcal, atypical and viral etiologies.

RESULTS

PCT and CRP showed significant correlation with a bacterial etiology of lower respiratory tract infection. No significance was found for leukocyte count. Using a cutoff point of 2 ng/ml for PCT and 65 mg/l for CRP, the sensitivities and specificities for distinguishing bacterial from viral lower respiratory tract infections were 68.6 and 79.4% for PCT and 79.1 and 67.1% for CRP. The sensitivities and specificities for distinguishing pneumococcal from other etiologies were 90.3 and 74.1% for PCT and 90.3 and 60% for CRP, respectively.

CONCLUSIONS

High PCT and CRP values show a significant correlation with the bacterial etiology of lower respiratory tract infection. PCT and CRP show good sensitivity for distinguishing pneumococcal from other etiologies. PCT shows higher specificity than CRP. PCT and CRP can help make decisions about antibiotic therapy in children with lower respiratory tract infections.

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.

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.

Laboratory diagnosis of Mycoplasma pneumoniae infection

Diagnosis of Mycoplasma pneumoniae infection is challenging due to the fastidious nature of the pathogen, the considerable seroprevalence, and the possibility of transient asymptomatic carriage. During recent years, various new techniques have been adapted for the diagnosis of M. pneumoniae infection, notably in the field of molecular biology. Standard polymerase chain reaction (PCR) is currently the method of choice for direct pathogen detection, but several PCR-related methods provide enhanced sensitivity or more convenient handling procedures, and have been successfully applied for research purposes. Among these techniques are real-time PCR, nested PCR, reverse transcriptase PCR (RT-PCR) and multiplex PCR. Generally, amplification-based methods have replaced hybridization assays and direct antigen detection. Serology, which is the basic strategy for mycoplasma diagnosis in routine clinical practice, has been improved by the widespread availability of sensitive assays for separate detection of different antibody classes. For the diagnosis of mycoplasma pneumonia, serology and direct pathogen detection should be combined. Extrapulmonary diseases may be diagnosed by direct pathogen detection alone, but the value of this diagnostic approach is limited by the probably immunologically mediated pathogenesis of some manifestations. This review summarizes the current state of Mycoplasma pneumoniae diagnosis, with special reference to molecular techniques. The value of different methods for routine diagnosis and research purposes is discussed.

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.

[Community-acquired pneumonia in children: etiology and treatment]

Due to their very different etiological agents, community-acquired pneumoniae in children frequently require empiric antibiotic therapy in emergency. Streptococcus pneumoniae represents between 15 to 30% of the etiologies and has unspecific diagnostic procedures; as a matter of fact radiological lobar consolidation is seen in less than half of cases, and laboratory data, except for high procalcitonin level, are poorly reliable. Pneumonia due to Mycoplasma pneumoniae is frequent after 2 years of age, reaching 40 to 60% of causes in ambulatory teenagers; it must be treated with macrolides as sequellae are possible. The exact number of viral pneumonia is difficult to establish because of the lack of reliable diagnostic methods. If bacterial superinfections are probably overestimated during acute phase, viral infections may lead to bacterial pneumonia 2 to 4 weeks after the initial episode. Empiric antibiotic treatment must take into account pneumococci and their penicillin-resistant strains. Amoxicillin is the antibiotic of choice, having a higher efficacy on resistant pneumococci than oral cephalosporins. In case of clinical failure of amoxicillin, mycoplasma infection must be considered and patient must receive macrolides. Future epidemiology will be affected by anti-pneumococcal immunisation but difficulties in diagnosis and empiric antibiotic treatment will probably remain. Studies in immunised children are needed to evaluate the importance of pneumococcal infections due to serotypes not included in the vaccine.

Procalcitonin in children admitted to hospital with community acquired pneumonia

AIMS

To assess the sensitivity, specificity, and predictive value of procalcitonin (PCT) in differentiating bacterial and viral causes of pneumonia.

METHODS

A total of 72 children with community acquired pneumonia were studied. Ten had positive blood culture for Streptococcus pneumoniae and 15 had bacterial pneumonia according to sputum analysis (S pneumoniae in 15, Haemophilus influenzae b in one). Ten patients had Mycoplasma pneumoniae infection and 37 were infected with viruses, eight of whom had viral infection plus bacterial coinfection. PCT concentration was compared to C reactive protein (CRP) concentration and leucocyte count, and, if samples were available, interleukin 6 (IL-6) concentration.

RESULTS

PCT concentration was greater than 2 microg/l in all 10 patients with blood culture positive for S pneumoniae; in eight of these, CRP concentration was above 60 mg/l. PCT concentration was greater than 1 microg/l in 86% of patients with bacterial infection (including Mycoplasma and bacterial superinfection of viral pneumonia). A CRP concentration of 20 mg/l had a similar sensitivity but a much lower specificity than PCT (40% v 86%) for discriminating between bacterial and viral causes of pneumonia. PCT concentration was significantly higher in cases of bacterial pneumonia with positive blood culture whereas CRP concentration was not. Specificity and sensitivity were lower for leucocyte count and IL-6 concentration.

CONCLUSIONS

PCT concentration, with a threshold of 1 microg/l is more sensitive and specific and has greater positive and negative predictive values than CRP, IL-6, or white blood cell count for differentiating bacterial and viral causes of community pneumonia in untreated children admitted to hospital as emergency cases.

Serum C-reactive protein cannot differentiate bacterial and viral aetiology of community-acquired pneumonia in children in primary healthcare settings

Whether serum C-reactive protein (CRP) can be used to distinguish bacterial from viral pneumonia was studied in 193 paediatric patients who were identified in a prospective, population-based study. The proportion of patients < 5 y of age was 51%, 53% of these and 12% of the older patients were treated in hospital. Pneumococcal aetiology of infection was studied in paired sera by antibody and immune-complex assays, and chlamydial, mycoplasmal and viral aetiologies by routine antibody assays. CRP concentration was measured by immunoturbidometry. Pneumococcal infection (mixed infections with other agents included) was present in 57 cases, mycoplasmal and/or chlamydial infection (pneumococcal infections excluded) in 43, and viral infection (pneumococcal, mycoplasmal and chlamydial infections excluded) in 29 cases. The mean CRP concentrations (95% confidence interval) in these groups were 26.8 mg/l (20.1-33.5 mg/l), 31.8 mg/l (20.5-33.1 mg/l) and 26.1 mg/l (19.1-33.1 mg/l), respectively, and 24.9 mg/l (18.8-31.0 mg/l) in patients with no aetiological findings. When CRP values were compared between the 2 diagnostic groups of pneumococcal infections (antibody and immune-complex positive) no difference was found. In infants < 12 months of age the mean CRP concentration was 14.6 mg/l, and in 11 (65%) of them it was unmeasurable (< 10 mg/l). No significant differences were seen between hospitalized patients and outpatients. In conclusion, CRP concentration had no significant association with the microbial aetiology of pneumonia.

Clinical use of cefuroxime in paediatric community-acquired pneumonia

Cefuroxime has been recommended as a component of treatment for community-acquired pneumonia (CAP) in guidelines produced by several groups, including the US and British Thoracic Societies. It is effective in vitro against the major bacterial pathogens in CAP but it needs to be given with an agent that is active against Mycoplasma, Chlamydia or Legionella spp. if the presence of any of these organisms is suspected. Cefuroxime penetrates respiratory tissue effectively after either parenteral or oral administration, and it has a pharmacodynamic profile which suggests that adequate cover can be achieved with oral therapy for respiratory pathogens susceptible to cefuroxime concentrations of 4 mg/L or less. This break-point is applicable to oral monotherapy and to sequential therapy regimens for the treatment of pneumonia. Cefuroxime can be used either orally or parenterally and it is approved in many countries for the treatment of adult pneumonia by either route. The oral form, cefuroxime axetil, has been used extensively in the treatment of children aged over 3 months but its use in paediatric pneumonia has not been reviewed. The present review summarises clinical experience in the treatment of bacterial pneumonia, of varying severity, in children. The data show that children with severe pneumonia, including those with pleural effusion or complications, can be treated with a full course of intravenous cefuroxime therapy, whereas hospitalised children whose pneumonia stabilises rapidly after initial intravenous therapy can change to oral cefuroxime axetil after 24 to 72 hours and may be able to return home. Oral cefuroxime axetil was appropriate for patients with milder pneumonia managed either in hospital or at home.

[New spectra of resistance of the main bacteria of the respiratory tract]

Management of acute pneumonia requires knowledge of current etiologic agents. Haemophilus influenzae and Streptococcus pneumoniae are the main responsible pathogens. Changes in epidemiology particularly occur in the susceptibility of antibiotics to S pneumoniae which is the main target of antimicrobial therapy.