Reappraisal of lung tap: review of an old method for better etiologic diagnosis of childhood pneumonia

Respiratory viruses among children with non-severe community-acquired pneumonia: A prospective cohort study

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Respiratory viruses were detected in almost all children with non-severe pneumonia.

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Multiple virus detection comprised two thirds of these cases.

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RSVA-B, FluA-B, PIV1-4 were similarly found among multiple or sole detection cases.

Background

Community-acquired pneumonia (CAP) causes a major burden to the health care system among children under-5 years worldwide. Information on respiratory viruses in non-severe CAP cases is scarce.

Objectives

To estimate the frequency of respiratory viruses among non-severe CAP cases.

Study design

Prospective study conducted in Salvador, Brazil. Out of 820 children aged 2–59 months with non-severe CAP diagnosed by pediatricians (respiratory complaints and radiographic pulmonary infiltrate/consolidation), recruited in a clinical trial (ClinicalTrials.gov Identifier NCT01200706), nasopharyngeal aspirate samples were obtained from 774 (94.4%) patients and tested for 16 respiratory viruses by PCRs.

Results

Viruses were detected in 708 (91.5%; 95%CI: 89.3–93.3) cases, out of which 491 (69.4%; 95%CI: 65.9–72.7) harbored multiple viruses. Rhinovirus (46.1%; 95%CI: 42.6–49.6), adenovirus (38.4%; 95%CI: 35.0–41.8), and enterovirus (26.5%; 95%CI: 23.5–29.7) were the most commonly found viruses. The most frequent combination comprised rhinovirus plus adenovirus. No difference was found in the frequency of RSVA (16.1% vs. 14.6%; P = 0.6), RSVB (10.9% vs. 13.2%; P = 0.4) influenza (Flu) A (6.3% vs. 5.1%; P = 0.5), FluB (4.5% vs. 1.8%; P = 0.09), parainfluenza virus (PIV) 1 (5.1% vs. 2.8%; P = 0.2), or PIV4 (7.7% vs. 4.1%; P = 0.08), when children with multiple or sole virus detection were compared. Conversely, rhinovirus, adenovirus, enterovirus, bocavirus, PIV2, PIV3, metapneumovirus, coronavirus OC43, NL63, 229E were significantly more frequent among cases with multiple virus detection.

Conclusions

Respiratory viruses were detected in over 90% of the cases, out of which 70% had multiple viruses. Several viruses are more commonly found in multiple virus detection whereas other viruses are similarly found in sole and in multiple virus detection.

Etiology of Childhood Pneumonia: What We Know, and What We Need to Know! : Based on 5th Dr. IC Verma Excellence Oration Award

Childhood community acquired pneumonia continues to be an important clinical problem at the individual, institutional and community levels. Determination of microbial etiology is critical to develop evidence-based management (therapeutic and prophylactic) decisions. For decades, the approach to this relied on culture of lung aspirate specimens obtained from children with radiographically confirmed pneumonia, before administering antibiotics. Such studies revealed the major bacteria associated with pneumonia, prompting the World Health Organization to develop a highly sensitive clinical definition of pneumonia and advocate empiric antibiotic therapy; in order to save lives (focusing on community settings lacking resources for diagnostic tests). However, it spawned research studies conducted in/from/by institutions enrolling children with the relatively non-specific WHO definition of pneumonia. Specificity got further compromised by abandoning lung aspiration and using naso/oro pharyngeal specimens; even in children who had received antibiotics. This led to the recovery of viruses more often than bacteria. The use of highly sensitive molecular based diagnostics (especially PCR) facilitated the detection of multiple organisms (bacteria, viruses, atypical organisms and even fungal species); making it difficult to attribute etiology in individual cases. This challenge was sought to be addressed through the multi-site PERCH Study (Pneumonia Etiology Research for Child Health), designed as a case-control study to conclusively determine the etiology of pneumonia. However, despite a slew of publications, the answer to the central question of etiology has not emerged so far. Since none of the PERCH Study sites was located in India, the Community Acquired Pneumonia Etiology Study (CAPES) was conducted at Chandigarh. This turned out to be the largest single-centre pneumonia etiology study, and generated a wealth of data. This article summarizes the current challenges in pneumonia etiology research; outlines the key observations from the PERCH and CAPES projects, as well as other important studies; and suggests a way forward for pneumonia etiology research in the current era.

Dexamethasone for Parapneumonic Pleural Effusion: A Randomized, Double-Blind, Clinical Trial

OBJECTIVE

To assess whether dexamethasone (DXM) decreases the time to recovery in patients with parapneumonic pleural effusion.

STUDY DESIGN

This was a multicenter, randomized, double blind, parallel-group, placebo-controlled clinical trial of 60 children, ranging in age from 1 month to 14 years, with community-acquired pneumonia (CAP) and pleural effusion. Patients received either intravenous DXM (0.25?mg/kg/dose) or placebo every 6 hours over a period of 48 hours, along with antibiotics. The primary endpoint was the time to recovery in hours, defined objectively. We also evaluated complications and adverse events.

RESULTS

Among the 60 randomized patients (mean age, 4.7 years; 58% female), 57 (95%) completed the study. Compared with placebo recipients, the patients receiving DXM had a shorter time to recovery, after adjustment by severity group and stratification by center (hazard ratio, 1.95; 95% CI, 1.10-3.45; P?=?.021). The median time to recovery for patients receiving DXM was 68 hours (2.8 days) shorter than patients receiving placebo (109 hours vs 177 hours; P?=?.037). In exploratory subgroup analysis, the median time to recovery for patients with simple effusion receiving DXM was 76 hours (3.1 days) shorter than for patients with simple effusion receiving placebo (P?=?.017). The median time to recovery for patients with complicated effusion receiving DXM was 14 hours (0.5 days) shorter than for patients with complicated effusion receiving placebo (P?=?.66). The difference in the effect of DXM in the 2 severity groups was not statistically significant (P?=?.138 for interaction). There were no significant differences in complications or adverse events attributable to the study drugs, except for hyperglycemia.

CONCLUSION

In this trial, DXM seemed to be a safe and effective adjunctive therapy for parapneumonic pleural effusion.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01261546.

State of the art thoracic ultrasound: intervention and therapeutics

The use of thoracic ultrasound outside the radiology department and in everyday clinical practice is becoming increasingly common, having been incorporated into standards of care for many specialties. For the majority of practitioners, their experience of, and exposure to, thoracic ultrasound will be in its use as an adjunct to pleural and thoracic interventions, owing to the widely recognised benefits for patient safety and risk reduction. However, as clinicians become increasingly familiar with the capabilities of thoracic ultrasound, new directions for its use are being sought which might enhance practice and patient care. This article reviews the ways in which the advent of thoracic ultrasound is changing the approach to the investigation and treatment of respiratory disease from an interventional perspective. This will include the impact of thoracic ultrasound on areas including patient safety, diagnostic and therapeutic procedures, and outcome prediction; and will also consider potential future research and clinical directions.

Comparison of the frequency of bacterial and viral infections among children with community-acquired pneumonia hospitalized across distinct severity categories: a prospective cross-sectional study

Background

The comparison of the frequencies of bacterial and viral infections among children with community-acquired pneumonia (CAP) admitted in distinct severity categories, in an original study, is lacking in literature to-date. We aimed to achieve this goal.

Methods

Children aged 2-59-months-old hospitalized with CAP were included in this prospective study in Salvador, Brazil. Clinical data and biological samples were collected to investigate 11 viruses and 8 bacteria. Severity was assessed by using the World Health Organization criteria.

Results

One hundred eighty-one patients were classified as “non-severe” (n = 53; 29.3 %), “severe” (n = 111; 61.3 %), or “very severe” (n = 17; 9.4 %) CAP. Overall, aetiology was detected among 156 (86.2 %) cases; viral (n = 84; 46.4 %), bacterial (n = 26; 14.4 %) and viral-bacterial (n = 46; 25.4 %) infections were identified. Viral infection frequency was similar in severe/very severe and non-severe cases (46.1 % vs. 47.2 %; p = 0.9). Pneumococcal infection increased across “non-severe” (13.2 %), “severe” (23.4 %), and “very severe” (35.3 %) cases (qui-squared test for trend p = 0.04). Among patients with detected aetiology, after excluding cases with co-infection, the frequency of sole bacterial infection was different (p = 0.04) among the categories; non-severe (12.5 %), severe (29.3 %) or very severe (55.6 %). Among these patients, sole bacterial infection was independently associated with severity (OR = 4.4 [95 % CI:1.1–17.6]; p = 0.04) in a model controlled for age (OR = 0.7 [95 % CI:0.5–1.1]; p = 0.1).

Conclusions

A substantial proportion of cases in distinct severity subgroups had respiratory viral infections, which did not differ between severity categories. Bacterial infection, particularly pneumococcal infection, was more likely among severe/very severe cases.

Electronic supplementary material

The online version of this article (doi:10.1186/s12887-016-0645-3) contains supplementary material, which is available to authorized users.

A review of the role of Haemophilus influenzae in community-acquired pneumonia

In an era when Haemophilus influenzae type b (Hib) conjugate vaccine is widely used, the incidence of Hib as a cause of community-acquired pneumonia (CAP) has dramatcally declined. Non-typeable H. influenzae (NTHi) strains and, occasionally, other encapsulated serotypes of H. influenzae are now the cause of the majority of invasive H. influenzae infectons, including bacteraemic CAP. NTHi have long been recognised as an important cause of lower respiratory tract infecton, including pneumonia, in adults, especially those with underlying diseases. The role of NTHi as a cause of non-bacteraemic CAP in children is less clear. In this review the evidence for the role of NTHi and capsulated strains of H. influenzae will be examined.

Clinical and Laboratory Potential Predictors of Blood Culture Positivity in Under Five Children with Clinically Severe Pneumonia - Khartoum -Sudan

BACKGROUND

Blood culture is necessary for appropriate management of clinically severe pneumonia in children under five years of age. However, in limited resource countries it might be unduly costly and waste of valuable time because of the high negative culture rate.

OBJECTIVES

This study aims to identify clinical and laboratory parameters that potentially predict a positive blood culture in cases of severe pneumonia.

MATERIALS AND METHODS

A hospital based study, enrolled 189 cases satisfying the WHO definition of severe pneumonia. Age, gender, clinical history, physical examination, temperature, complete blood count, C-reactive protein, blood culture and Chest X Ray for all the patients were recorded.

RESULTS

Forty one patients had positive blood culture giving a prevalence of 21.7%. All variables were used in a dichotomous manner. White Blood Count (WBC) more than 20 000, very high C-reactive protein (C-RP ≥8mg/L) and Temperature more than 40(o)C, had a positive predictive value of 46.1%, 44.3% and 40.0% respectively for a positive culture as well as a Negative Predictive Value of 91.1%, 91.6% and 91.7% respectively. The WBC more than 20 000 and temperature above 40(o)C had a significant association with a positive blood culture. Their adjusted Odds Ratios were 3.9 (95% CI: 1.4-10.90) and 3.1 (95% CI: 1.2-8.4) respectively. This was not the case for C-RP (Odds Ratio=2.2, 95% CI: 0.7-2.2) or positive Chest X Ray (Odds Ratio=1.5, 95% CI: 0.6-3.6).

CONCLUSION AND RECOMMENDATION

Temperature of more than 40(o)C, Very high C-RP and WBC of more than 20 000 are good indicators of a potential positive blood culture. It is therefore recommended that further research be undertaken to refine these predictors as screening tools before resorting to blood culture. It is also recommended that antibiotic treatment may be initiated on the basis of the high temperature and WBC, while waiting for the culture results.

Vaccine-induced waning of Haemophilus influenzae empyema and meningitis, Angola

In Angola during 2003–2012, we detected Haemophilus influenzae in 18% of 2,634 and 26% of 2,996 bacteriologically positive pleural or cerebrospinal fluid samples, respectively, from children. After vaccination launch in 2006, H. influenzae empyema declined by 83% and meningitis by 86%. Severe H. influenzae pneumonia and meningitis are preventable by vaccination.

Community-acquired pneumonia in children: current challenges and future directions

Pneumonia is a commonly encountered illness and the leading cause of death in children under 5 years of age. Our current management strategies remain less than optimal in part because we do not have adequate tools to determine etiology, classify patients and predict their outcomes. Studies in the last decade have demonstrated that viruses are commonly detected in children with pneumonia, but on many occasions this is not sufficient to establish a clear etiologic diagnosis since bacterial coinfection cannot be excluded. Gene expression profile analysis provides a comprehensive assessment of the host response to infection. Preliminary data suggest that transcriptional profile analysis and measurement of Molecular Distance to Health (MDTH) scores allows more precise patient classification than current diagnostic techniques and laboratory markers. Application of this tool to the evaluation of children with pneumonia may enhance our clinical decision making process and ultimately improve patient outcomes.

Population-based incidence of community-acquired pneumonia hospitalization in Hong Kong children younger than 5 years before universal conjugate pneumococcal immunization

OBJECTIVES

We sought to document the incidence of pediatric hospitalization for bacterial pneumonia before universal childhood conjugate pneumococcal vaccination using two different methods of diagnosis.

METHODS

By following the World Health Organization (WHO) chest radiography (CXR) protocol, two radiologists independently read the CXRs of a cohort of systematically recruited children younger than 5 years. The children had acute respiratory infections and were admitted to one of two hospitals that care for 72.5% of all pediatric admissions on Hong Kong Island. Medical records were reviewed for clinical manifestation and to identify bacterial pneumonia diagnosed by pediatricians.

RESULTS

In children younger than 5 years, the incidences of bacterial pneumonia, as diagnosed by pediatricians and by the WHO CXR standard, were 775.7 per 100,000 population [95% confidence interval (CI, 591.8-998.3)] and 439.5 per 100,000 population (95% CI, 304.6-614.5), respectively. The study period was from 2002 to 2004.

CONCLUSION

This study provided a reliable baseline estimate of the hospitalization burden of pneumococcal pneumonia in Hong Kong children before the advent of universal conjugate pneumococcal vaccination.

Prevention ofHaemophilus influenzaetype b disease: past success and future challenges

Haemophilus influenzae type b (Hib) is responsible for significant morbidity and mortality worldwide, particularly in children under 5 years of age. In countries where the Hib conjugate vaccine is not routinely used, Hib is a leading cause of childhood pneumonia and meningitis. Routine use of the Hib conjugate vaccines has resulted in a remarkable decline in Hib disease in developed and developing countries. However, Hib conjugate vaccines are not routinely available in most developing countries, many of which have high burdens of Hib disease. This review outlines the pathogenesis and epidemiology of Hib disease, and the various options for prevention.

Evaluation of the effectiveness of Haemophilus influenzae type b conjugate vaccine introduction against radiologically-confirmed hospitalized pneumonia in young children in Ukraine

OBJECTIVE

Haemophilus influenzae type b (Hib) conjugate vaccine was included into the national vaccination schedule of Ukraine in 2006. The objective of this study was to demonstrate the effectiveness of Hib conjugate vaccine against radiologically-confirmed hospitalized pneumonia in children.

STUDY DESIGN

Children <2 years old with radiologically confirmed pneumonia admitted to 11 participating hospitals in Kiev and Dnepropetrovsk between April 2007 and June 2009 were included in a case-control evaluation. Four controls were matched to each case by date of birth (within 14 days) and outpatient clinic. We estimated ORs for vaccination and vaccine effectiveness ((1 - OR)*100%) using conditional logistic regression, adjusting for comorbid conditions and contraindications for vaccination.

RESULTS

We enrolled 188 case-children and 735 controls. Median age was 16 months (range 4-24 months). Fifty-one percent of cases and 67% of controls received ≥1 doses of Hib conjugate vaccine; 26% of cases and 37% of controls received ≥3 doses. The effectiveness of ≥1 dose Hib conjugate vaccine was estimated at 45% (95% CI 18%-63%).

CONCLUSIONS

Our study showed that Hib infections are important causes of hospitalized radiologically confirmed pneumonia in young children in Ukraine.

Cost-effectiveness of new pneumococcal conjugate vaccines in Turkey: a decision analytical model

Background

Streptococcus pneumoniae infections, which place a considerable burden on healthcare resources, can be reduced in a cost-effective manner using a 7-valent pneumococcal conjugate vaccine (PCV-7). We compare the cost effectiveness of a 13-valent PCV (PCV-13) and a 10-valent pneumococcal non-typeable Haemophilus influenzae protein D conjugate vaccine (PHiD-CV) with that of PCV-7 in Turkey.

Methods

A cost-utility analysis was conducted and a decision analytical model was used to estimate the proportion of the Turkish population <10 years old that would experience 10 mutually exclusive outcomes over the course of 1 year from a perspective of a healthcare system. Model outcomes were adjusted according to the population demographics and region-specific serotype distribution in Turkey. Health outcomes and direct healthcare costs were simulated for PCV-7, PCV-13 and PHiD-CV.

Results

PCV-13 and PHiD-CV are projected to have a substantial impact on pneumococcal disease in Turkey versus PCV-7, with 2,223 and 3,156 quality-adjusted life years (QALYs) and 2,146 and 2,081 life years, respectively, being saved under a 3+1 schedule. Projections of direct medical costs showed that a PHiD-CV vaccination programme would provide the greatest cost savings, offering additional savings of US$11,718,813 versus PCV-7 and US$8,235,010 versus PCV-13. Probabilistic sensitivity analysis showed that PHiD-CV dominated PCV-13 in terms of QALYs gained and cost savings in 58.3% of simulations.

Conclusion

Under the modeled conditions, PHiD-CV would provide the most cost-effective intervention for reducing pneumococcal disease in Turkish children.

Etiology and Incidence of viral and bacterial acute respiratory illness among older children and adults in rural western Kenya, 2007-2010

BACKGROUND

Few comprehensive data exist on disease incidence for specific etiologies of acute respiratory illness (ARI) in older children and adults in Africa.

METHODOLOGY/PRINCIPAL FINDINGS

From March 1, 2007, to February 28, 2010, among a surveillance population of 21,420 persons >5 years old in rural western Kenya, we collected blood for culture and malaria smears, nasopharyngeal and oropharyngeal swabs for quantitative real-time PCR for ten viruses and three atypical bacteria, and urine for pneumococcal antigen testing on outpatients and inpatients meeting a ARI case definition (cough or difficulty breathing or chest pain and temperature >38.0 °C or oxygen saturation <90% or hospitalization). We also collected swabs from asymptomatic controls, from which we calculated pathogen-attributable fractions, adjusting for age, season, and HIV-status, in logistic regression. We calculated incidence by pathogen, adjusting for health-seeking for ARI and pathogen-attributable fractions. Among 3,406 ARI patients >5 years old (adjusted annual incidence 12.0 per 100 person-years), influenza A virus was the most common virus (22% overall; 11% inpatients, 27% outpatients) and Streptococcus pneumoniae was the most common bacteria (16% overall; 23% inpatients, 14% outpatients), yielding annual incidences of 2.6 and 1.7 episodes per 100 person-years, respectively. Influenza A virus, influenza B virus, respiratory syncytial virus (RSV) and human metapneumovirus were more prevalent in swabs among cases (22%, 6%, 8% and 5%, respectively) than controls. Adenovirus, parainfluenza viruses, rhinovirus/enterovirus, parechovirus, and Mycoplasma pneumoniae were not more prevalent among cases than controls. Pneumococcus and non-typhi Salmonella were more prevalent among HIV-infected adults, but prevalence of viruses was similar among HIV-infected and HIV-negative individuals. ARI incidence was highest during peak malaria season.

CONCLUSIONS/SIGNIFICANCE

Vaccination against influenza and pneumococcus (by potential herd immunity from childhood vaccination or of HIV-infected adults) might prevent much of the substantial ARI incidence among persons >5 years old in similar rural African settings.

A preliminary study of pneumonia etiology among hospitalized children in Kenya

BACKGROUND

Pneumonia is the leading cause of childhood death in the developing world. Higher-quality etiological data are required to reduce this mortality burden.

METHODS

We conducted a case-control study of pneumonia etiology among children aged 1-59 months in rural Kenya. Case patients were hospitalized with World Health Organization-defined severe pneumonia (SP) or very severe pneumonia (VSP); controls were outpatient children without pneumonia. We collected blood for culture, induced sputum for culture and multiplex polymerase chain reaction (PCR), and obtained oropharyngeal swab specimens for multiplex PCR from case patients, and serum for serology and nasopharyngeal swab specimens for multiplex PCR from case patients and controls.

RESULTS

Of 984 eligible case patients, 810 (84%) were enrolled in the study; 232 (29%) had VSP. Blood cultures were positive in 52 of 749 case patients (7%). A predominant potential pathogen was identified in sputum culture in 70 of 417 case patients (17%). A respiratory virus was detected by PCR from nasopharyngeal swab specimens in 486 of 805 case patients (60%) and 172 of 369 controls (47%). Only respiratory syncytial virus (RSV) showed a statistically significant association between virus detection in the nasopharynx and pneumonia hospitalization (odds ratio, 12.5; 95% confidence interval, 3.1-51.5). Among 257 case patients in whom all specimens (excluding serum specimens) were collected, bacteria were identified in 24 (9%), viruses in 137 (53%), mixed viral and bacterial infection in 39 (15%), and no pathogen in 57 (22%); bacterial causes outnumbered viral causes when the results of the case-control analysis were considered.

CONCLUSIONS

A potential etiology was detected in >75% of children admitted with SP or VSP. Except for RSV, the case-control analysis did not detect an association between viral detection in the nasopharynx and hospitalization for pneumonia.

Specimen collection for the diagnosis of pediatric pneumonia

Diagnosing the etiologic agent of pneumonia has an essential role in ensuring the most appropriate and effective therapy for individual patients and is critical to guiding the development of treatment and prevention strategies. However, establishing the etiology of pneumonia remains challenging because of the relative inaccessibility of the infected tissue and the difficulty in obtaining samples without contamination by upper respiratory tract secretions. Here, we review the published and unpublished literature on various specimens available for the diagnosis of pediatric pneumonia. We discuss the advantages and limitations of each specimen, and discuss the rationale for the specimens to be collected for the Pneumonia Etiology Research for Child Health study.

Health and economic impact of PHiD-CV in Canada and the UK: a Markov modelling exercise

OBJECTIVE

The spectrum of diseases caused by Streptococcus pneumoniae and non-typeable Haemophilus influenzae (NTHi) represents a large burden on healthcare systems around the world. Meningitis, bacteraemia, community-acquired pneumonia (CAP), and acute otitis media (AOM) are vaccine-preventable infectious diseases that can have severe consequences. The health economic model presented here is intended to estimate the clinical and economic impact of vaccinating birth cohorts in Canada and the UK with the 10-valent, pneumococcal non-typeable Haemophilus influenzae protein D conjugate vaccine (PHiD-CV) compared with the newly licensed 13-valent pneumococcal conjugate vaccine (PCV-13).

METHODS

The model described herein is a Markov cohort model built to simulate the epidemiological burden of pneumococcal- and NTHi-related diseases within birth cohorts in the UK and Canada. Base-case assumptions include estimates of vaccine efficacy and NTHi infection rates that are based on published literature.

RESULTS

The model predicts that the two vaccines will provide a broadly similar impact on all-cause invasive disease and CAP under base-case assumptions. However, PHiD-CV is expected to provide a substantially greater reduction in AOM compared with PCV-13, offering additional savings of Canadian $9.0 million and £4.9 million in discounted direct medical costs in Canada and the UK, respectively.

LIMITATIONS

The main limitations of the study are the difficulties in modelling indirect vaccine effects (herd effect and serotype replacement), the absence of PHiD-CV- and PCV-13-specific efficacy data and a lack of comprehensive NTHi surveillance data. Additional limitations relate to the fact that the transmission dynamics of pneumococcal serotypes have not been modelled, nor has antibiotic resistance been accounted for in this paper.

CONCLUSION

This cost-effectiveness analysis suggests that, in Canada and the UK, PHiD-CV's potential to protect against NTHi infections could provide a greater impact on overall disease burden than the additional serotypes contained in PCV-13.

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.

Neonatal community-acquired pneumonia: pathogens and treatment

AIM

To analyse the bacterial pathogens and drug sensitivities for neonatal community-acquired pneumonia.

METHODS

Seven hundred sixty sputum samples from newborns with community-acquired pneumonia were cultured to determine microbial organisms present and their drug sensitivities.

RESULTS

Of the 760 specimens, 425 grew pathogens for a 55.9% positive rate. Among the 425 positive cultures, 278 grew gram-negative organisms (65.4%), 142 grew gram-positive organisms (33.3%), while 5 grew fungus (1.3%). The most common gram-negative organisms were Escherichia coli, Klebsiella pneumoniae and Hemophilus influenzae, while the most common gram-positive organisms were Staphylococcus aureus, Staphylococcus epidermidis and Staphylococcus haemolyticus. To the gram-negative organisms, the most sensitive drugs were meropenem, imipenem and amikacin, while to the gram-positive ones were vancomycin, teicoplanin and quinupristin/dalfopristin.

CONCLUSIONS

The most common causative bacteria were gram-negative organisms, which were highly sensitive to Meropenem, Imipenem and Amikacin, yet often treatable with more focused antibiotic coverage, which depended on the bacterium identified.

Use of serology and urine antigen detection to estimate the proportion of adult community-acquired pneumonia attributable toStreptococcus pneumoniae

Streptococcus pneumoniaeis a common cause of community-acquired pneumonia (CAP) but existing diagnostic tools have limited sensitivity and specificity. We enrolled adults undergoing chest radiography at three Indian Health Service clinics in the Southwestern United States and collected acute and convalescent serum for measurement of PsaA and PspA titres and urine for pneumococcal antigen detection. Blood and sputum cultures were obtained at the discretion of treating physicians. We compared findings in clinical and radiographic CAP patients to those in controls without CAP. Urine antigen testing showed the largest differential between CAP patients and controls (clinical CAP 13%, radiographic CAP 17%, control groups 2%). Serological results were mixed, with significant differences between CAP patients and controls for some, but not all changes in titre. Based on urine antigen and blood culture results, we estimated that 11% of clinical and 15% of radiographic CAP cases were due to pneumococcus in this population.

Pneumonia in severely malnourished children in developing countries - mortality risk, aetiology and validity of WHO clinical signs: a systematic review

OBJECTIVES

To quantify the degree by which moderate and severe degrees of malnutrition increase the mortality risk in pneumonia, to identify potential differences in the aetiology of pneumonia between children with and without severe malnutrition, and to evaluate the validity of WHO-recommended clinical signs (age-specific fast breathing and chest wall indrawing) for the diagnosis of pneumonia in severely malnourished children.

METHODS

Systematic search of the existing literature using a variety of databases (Medline, EMBASE, the Web of Science, Scopus and CINAHL).

RESULTS

Mortality risk: Sixteen relevant studies were identified, which universally showed that children with pneumonia and moderate or severe malnutrition are at higher risk of death. For severe malnutrition, reported relative risks ranged from 2.9 to 121.2; odds ratios ranged from 2.5 to 15.1. For moderate malnutrition, relative risks ranged from 1.2 to 36.5. Aetiology: Eleven studies evaluated the aetiology of pneumonia in severely malnourished children. Commonly isolated bacterial pathogens were Klebsiella pneumoniae, Staphylococcus aureus, Streptococcus pneumoniae, Escherichia coli, and Haemophilus influenzae. The spectrum and frequency of organisms differed from those reported in children without severe malnutrition. There are very few data on the role of respiratory viruses and tuberculosis. Clinical signs: Four studies investigating the validity of clinical signs showed that WHO-recommended clinical signs were less sensitive as predictors of radiographic pneumonia in severely malnourished children.

CONCLUSIONS

Pneumonia and malnutrition are two of the biggest killers in childhood. Guidelines for the care of children with pneumonia and malnutrition need to take into account this strong and often lethal association if they are to contribute to the UN Millennium Development Goal 4, aiming for substantial reductions in childhood mortality. Additional data regarding the optimal diagnostic approach to and management of pneumonia and malnutrition are required from regions where death from these two diseases is common.

Childhood bacterial respiratory diseases: past, present, and future

Pneumonia is the most serious acute respiratory infection and is caused by numerous etiologic agents, bacteria and viruses. Severe pneumonia is a major challenge to survival of children globally. In this article we examine the causes of global childhood mortality, and the distribution of childhood pneumonia mortality and morbidity, as well as the risk factors that affect pneumonia incidence. Although major bacterial and viral respiratory infections, such as diphtheria, measles, Haemophilus influenzae type b (Hib), and pneumococcal infections, are now preventable through vaccination, bacterial pneumonia, including severe pneumonia (those that require hospitalization), still remain a public health challenge in both resource-poor and wealthy countries. We therefore, review the published literature on the available vaccines and their potential effectiveness in further reducing the burden of childhood bacterial respiratory diseases. There is a need to conduct further epidemiologic studies for identifying the disease burden and for urgent implementation of proven cost-effective interventions. These interventions are a necessary part of public health actions to reduce childhood mortality, a major Millennium Development Goal. The role of vaccines in this regard is critical, as they represent a rapid and feasible intervention with an early and sustained impact.

Transthoracic fine-needle aspiration in the aetiological diagnosis of community-acquired pneumonia

Clin Microbiol Infect 2010; 16: 909–911

Abstract

To investigate the safety and practicability of conducting transthoracic fine‐needle aspiration (TFNA) in a general hospital setting, we applied the TFNA procedure to 20 patients hospitalized with community‐acquired pneumonia (CAP) within 36 h of admission. Also, a preliminary assessment was made of the potential value of adding TFNA to conventional methods of diagnostic microbiology. TFNA was easy to perform and caused little discomfort, and no serious adverse events were observed. In spite of ongoing antimicrobial treatment, a likely aetiological diagnosis was established for 14 of 20 (70%) of the patients. TFNA may provide important additional information on the aetiology of CAP.

Recommendations for treatment of childhood non-severe pneumonia

WHO recommendations for early antimicrobial treatment of childhood pneumonia have been effective in reducing childhood mortality, but the last major revision was over 10 years ago. The emergence of antimicrobial resistance, new pneumonia pathogens, and new drugs have prompted WHO to assemble an international panel to review the literature on childhood pneumonia and to develop evidence-based recommendations for the empirical treatment of non-severe pneumonia among children managed by first-level health providers. Treatment should target the bacterial causes most likely to lead to severe disease, including Streptoccocus pneumoniae and Haemophilus influenzae. The best first-line agent is amoxicillin, given twice daily for 3–5 days, although co-trimoxazole may be an alternative in some settings. Treatment failure should be defined in a child who develops signs warranting immediate referral or who does not have a decrease in respiratory rate after 48–72 h of therapy. If failure occurs, and no indication for immediate referral exists, possible explanations for failure should be systematically determined, including non-adherence to therapy and alternative diagnoses. If failure of the first-line agent remains a possible explanation, suitable second-line agents include high-dose amoxicillin–clavulanic acid with or without an affordable macrolide for children over 3 years of age.

Pneumonia and other respiratory infections

Pneumonia is a leading killer of children in developing countries and results in significant morbidity worldwide. This article reviews the management of pneumonia and its complications from the perspective of both developed and resource-poor settings. In addition, evidence-based management of other respiratory infections, including tuberculosis, is discussed. Finally, the management of common complications of pneumonia is reviewed.

Serotypes and pathogens in paediatric pneumonia

Multiple pathogens may cause pneumonia. Three vaccines with demonstrated or potentially major impact on paediatric pneumonia caused by pneumococcus and/or non-typable Haemophilus influenzae (NTHi) are projected to soon become globally available. Estimating the magnitude of this impact requires precise knowledge of the etiology of pneumonia. We reviewed studies to evaluate the relative importance of specific pneumococcal serotypes and NTHi as pneumonia pathogens. While emerging conjugate vaccines, especially those containing serotype 1, appear to have great potential toward the prevention of childhood pneumonia based on expanded serotype coverage, the importance of NTHi in childhood pneumonia has yet to be elucidated.

A multiplex PCR-based reverse line blot hybridization (mPCR/RLB) assay for detection of bacterial respiratory pathogens in children with pneumonia

OBJECTIVES

To develop and evaluate a novel method for simultaneous identification of 12 potential bacterial pathogens in children with community-acquired pneumonia.

METHODS

A multiplex PCR-based reverse line blot (mPCR/RLB) assay was developed, to identify 12 respiratory bacterial pathogens, namely Staphylococcus aureus, Streptococcus pneumoniae, Streptococcus pyogenes, Moraxella catarrhalis, Haemophilus influenzae, Haemophilus influenzae type b, Bordetella pertussis, Klebsiella pneumoniae, Legionella pneumophila, Mycobacterium tuberculosis, Chlamydia pneumoniae, Mycoplasma pneumoniae, and single (uniplex) PCRs were used for S. pneumoniae and H. influenzae only. In a preliminary evaluation, we compared the results of mPCR/RLB with those of single (uniplex) PCRs and culture of nasopharyngeal aspirates (NPAs) from 100 children under 5 years, admitted to Beijing Children's Hospital between October 2004 and May 2005, with pneumonia.

RESULTS

Reference strains and clinical isolates of all 12 target species were correctly identified by mPCR/RLB. Potential pathogens were isolated from one blood culture and 26% of respiratory cultures. One or more pathogens were identified in 70% of respiratory specimens--by mPCR/RLB in 63%, uPCR only in another 3%, culture only in 2%, and culture plus uPCR in 2%. The species most commonly identified were S. pneumoniae (54%) and H. influenzae (38%, including type b, 4%). Cultures were not performed for B. pertussis, M. tuberculosis, C. pneumoniae or M. pneumoniae but each was identified by mPCR/RLB in between one and four specimens. Two or more potential pathogens were identified in 35% of specimens. Ten of 14 S. pneumoniae isolates belonged to serotypes represented in the 11-valent pneumococcal conjugate vaccine.

CONCLUSIONS

The mPCR/RLB assay is a sensitive tool for identification of respiratory pathogens, including mixed infections and bacteria requiring special culture methods.

Bacterial Infections

In Osier’s time, bacterial pneumonia was a dreaded event, so important that he borrowed John Bunyan’s characterization of tuberculosis and anointed the pneumococcus, as the prime pathogen, “Captain of the men of death.”1 One hundred years later much has changed, but much remains the same. Pneumonia is now the sixth most common cause of death and the most common lethal infection in the United States. Hospital-acquired pneumonia is now the second most common nosocomial infection.2 It was documented as a complication in 0.6% of patients in a national surveillance study,3 and has been reported in as many as 20% of patients in critical care units.4 Furthermore, it is the leading cause of death among nosocomial infections.5 Leu and colleagues6 were able to associate one third of the mortality in patients with nosocomial pneumonia to the infection itself. The increase in hospital stay, which averaged 7 days, was statistically significant. It has been estimated that nosocomial pneumonia produces costs in excess of $500 million each year in the United States, largely related to the increased length of hospital stay.

Microbiological diagnostic procedures in respiratory infections: suppurative lung disease

Pursuing a microbiological diagnosis in suppurative lung disease can enable focused antibiotic therapy, identify pathogens of potential concern for infection control, and in some cases delineate a specific pathological process. Suppurative lung disease can be categorized as acute or chronic. Acute disease most commonly consists of lung abscess or parapneumonic empyema. The vast majority of chronic suppurative lung disease in childhood is due to cystic fibrosis. Samples from the respiratory tract offer the most useful information for diagnosis and management, but adjunctive information can also be obtained from serological methods, blood cultures and molecular techniques. The quality of respiratory tract samples is vital to aid accurate interpretation of results, and this varies according to the technique of collection. Antibiotic sensitivity testing is of particular importance in an era of evolving antibiotic resistance and can be problematical in cystic fibrosis.

Epidemiology, clinical characteristics and antimicrobial resistance patterns of community-acquired pneumonia in 1702 hospitalized children in Singapore

OBJECTIVE AND BACKGROUND

Childhood community-acquired pneumonia (CAP) remains a leading cause of morbidity and mortality worldwide. The features of childhood CAP vary between countries. The aim of this study was to delineate the clinical characteristics, complications, spectrum of pathogens and patterns of antimicrobial resistance associated with hospitalized cases of childhood CAP in Singapore.

METHODS

A retrospective study was conducted of patients discharged from Singapore's only children's hospital over a 3-year period with a principal diagnosis of CAP.

RESULTS

A total of 1702 children, with a median age of 4.2 years (range: 1 month-16.3 years) were enrolled. A pathogen was identifiable in 38.4% of cases, including Mycoplasma pneumoniae in 20.3%, typical respiratory bacteria in 10.3% (64.6%Streptococcus pneumoniae; 21.7% non-typeable Haemophilus influenzae), viruses in 5.5% and mixed bacterial/viral infections in 2%. The majority of M. pneumoniae infections were in school-aged children (>5 years). Severity of infection was greater in CAP caused by typical bacteria, as reflected by length of hospital stay, CRP level, white cell and absolute neutrophil counts. Mortality from typical bacterial infections (8.9%) exceeded that from M. pneumoniae (0.3%) and viral pneumonias (0%) (P < 0.001). Aminopenicillins were often prescribed empirically for suspected S. pneumoniae and H. influenzae infections; however, resistance to these agents was frequently documented among S. pneumoniae (58.5%) and H. influenzae isolates (51%).

CONCLUSION

In Singaporean children hospitalized with CAP, M. pneumoniae is the most commonly identified causative organism, followed by common respiratory viruses, S. pneumoniae and H. influenzae. Streptococcus pneumoniae and H. influenzae are associated with greater severity of infection than other organisms, and have high levels of resistance to commonly prescribed antibiotics.

Detection of antigenuria for diagnosis of invasive Haemophilus influenzae type b disease

BACKGROUND

Haemophilus influenzae type b (Hib) diseases are responsible for an estimated 400,000 childhood deaths, mostly in developing countries.

OBJECTIVES

To determine the value of the Wellcogen quantitative latex agglutination test (LA) in urine for the diagnosis of Hib pneumonia and meningitis.

METHODS

Healthy and sick children aged <5 y were enrolled in Dhaka Shishu (Children's) Hospital. Boiled and non-concentrated urine specimens underwent LA testing. In vaccinated subjects, urine was tested by LA at 24 h, 4-6 and 7-10 d after vaccination.

RESULTS

Of 1302 enrolled cases, 201 were healthy (90 Hib vaccine recipients and 111 provided NP) and 1101 were sick with either pneumonia (n=974) or meningitis (n=127). Among the healthy children enrolled, 41 (41/111, 37%) were colonised with Hib and two (2/41, 5%) were positive by LA test. Hib antigenuria among the children who had received Hib vaccination was mainly detected only on day 1 (7/90, 8%) of vaccination. Among the sick children, LA test for Hib antigen was positive for all confirmed cases of Hib pneumonia (10) and meningitis (35). In contrast, none of the urine specimens from the cases with a known aetiology other than Hib (n=104) was positive. Quantitative analysis of antigenuria of sick children showed that it is positive at least up to 1:8 and 1:16 dilutions for pneumonia and meningitis, respectively, in contrast with <or=1:4 for healthy children. In addition to the ten cases of culture-proven Hib, the test detected an additional 16 Hib pneumonia cases among children diagnosed as pneumonia, based on the presence of antigenuria >or=1:8 dilutions.

CONCLUSIONS

The Wellcogen LA test for Hib using boiled and non-concentrated urine is more sensitive than blood culture alone and is highly specific.

Bacterial pneumonia vaccines and childhood pneumonia: are we winning, refining, or redefining?

Bacterial pneumonia is a substantial cause of childhood morbidity and mortality worldwide, but determination of pathogen-specific burden remains a challenge. In less developed settings, the WHO recommended guidelines are useful for initiating care, but are non-specific. Blood culture has low sensitivity, while radiological findings are non-specific and do not discriminate between viral and bacterial causes of pneumonia. In vaccine probe studies, efficacy is dependent on the specificity of the study outcome to detect pneumonia and the impact of the vaccine on the selected outcome, and may underestimate the true burden of bacterial pneumonia. The rising incidence of antibiotic resistance, emerging respiratory pathogens, potential replacement pneumococcal disease following widespread introduction of pneumococcal polysaccharide-protein conjugate vaccine, the limited specificity of chest radiography, and the poor sensitivity of blood culture are substantial obstacles to accurate surveillance. We provide an overview of the diagnostic challenges of bacterial pneumonia and highlight the need for refining the current diagnostic approach to ensure adequate epidemiological surveillance of childhood pneumonia and the success, or otherwise, of any immunisation strategies.

Penicillin and gentamicin therapy vs amoxicillin/clavulanate in severe hypoxemic pneumonia

OBJECTIVE

To compare the efficacy of sequential injectable crystalline penicillin (C.pen) and gentamicin combination followed by oral amoxicillin with sequential IV and oral amoxicillin-clavulanate (amox-clav) in treatment of severe or very severe hypoxemic pneumonia.

METHODS

Children aged 2-59 months with WHO-defined severe or very severe pneumonia with hypoxemia (SpO2 < 90%) were included in the study. Patients with fever > 10 days, bacterial meningitis, prior antibiotic therapy > 24 hours, stridor, heart disease and allergy to any of the study drugs were excluded. They were randomly allocated to two groups--Group A and Group B. Group A received C. pen and gentamicin intravenously (IV), followed by oral amoxicillin and group B got amox-clav IV, followed by oral amox-clav. Minimum duration of IV therapy was 3 days and total 7 days. Respiratory rate, oxygen saturation and chest wall indrawing were monitored 6 hourly.

RESULTS

71 patients were included. There were two (5.2%) blood cultures positive in group A and three (9%) in group B. Organisms isolated were S. pneumoniae (n=3) and H. influenzae-b (n=2). There was only one treatment failure in each of the groups. One was due to penicillin resistant H. influenzae -b and the other was due to worsening of pneumonia. The mean time taken for normalization of tachypnea, hypoxia, chest wall indrawing and inability to feed was similar (P-N.S). Mean duration of IV therapy in group A was 76+/-25 hrs and group B was 75+/-24 hrs (p>0.1).

CONCLUSION

In children of 2-59 months, sequential injectable C. pen and gentamicin combination, followed by oral amoxicillin or sequential IV and oral amox-clav were equally effective for the treatment of severe or very severe hypoxemic community acquired pneumonia.

Usefulness of C-reactive protein to define pneumococcal conjugate vaccine efficacy in the prevention of pneumonia

OBJECTIVES AND METHODS

This study explored whether C-reactive protein (CRP) and/or procalcitonin levels were useful to measure vaccine efficacy (VE) and impact against the burden of pneumonia of a 9-valent pneumococcal conjugate vaccine (PCV), compared with chest radiograph-confirmed alveolar consolidation (CXR-AC) as an outcome. Sera obtained from children participating in a phase 3 PCV efficacy trial who were hospitalized for treatment of clinically diagnosed lower respiratory tract infection (C-LRTI) were retrospectively analyzed for CRP and procalcitonin measurements.

RESULTS

For non-human immunodeficiency virus (HIV)-infected children, the VE estimates for C-LRTI with CRP levels of > or =40 mg/dL (VE 26.3%; P = 0.003) or CRP levels of > or =120 mg/dL (VE 41.0%; P = 0.003) were 1.7-fold (P = 0.002) and 2.7-fold (P < 0.0001) greater, respectively, than that for CXR-AC (VE 15.1%; P= 0.15). The sensitivity of CXR-AC as an outcome to detect the burden of pneumonia prevented by PCV was 44% (95% confidence interval, 36-55%) in comparison with C-LRTI with CRP levels of > or =40 mg/dL and 73% (95% confidence interval, 58-92%) in comparison with C-LRTI with CRP levels of > or =120 mg/dL. CRP also helped to measure the PCV efficacy for children with C-LRTI but the absence of CXR-AC, for whom the outcome of C-LRTI with CRP levels of > or =40 mg/dL (VE 31.5%; P = 0.007) increased the VE estimate 19.8-fold (P < 0.0001) in comparison with C-LRTI alone (VE 1.6%; P = 0.78) and 3.2-fold (P = 0.005) in comparison with WHO-defined severe pneumonia (VE 10.0%; P = 0.17). Although there was a significant correlation between CRP and procalcitonin levels (Spearman's rho = 0.45; P < 0.0001), the use of procalcitonin levels did not improve either the specificity or sensitivity of measuring the effect of PCV against pneumonia for non-HIV-infected children. The observations were similar for HIV-infected children.

CONCLUSIONS

CRP levels of > or =40 mg/dL provide a better measure than chest radiographs to assess the effect of PCV in preventing pneumonia.

Rapid diagnosis of pneumococcal meningitis: implications for treatment and measuring disease burden

BACKGROUND

Streptococcus pneumoniae is the leading cause of childhood pneumonia and meningitis worldwide. Isolation of this organism, however, is uncommon in resource-poor countries, in part because of extensive use of prior antibiotics. A rapid, highly sensitive immunochromatographic test (ICT) for S. pneumoniae was evaluated for the diagnosis of meningitis.

METHODS

Cerebrospinal fluid (CSF) from 450 children with suspected meningitis was tested with ICT, and results were compared with CSF culture, latex agglutination test (LAT) and/or polymerase chain reaction (PCR). Serial CSF specimens from 11 patients were also evaluated for duration of positive results during effective antimicrobial therapy.

FINDINGS

All 122 cases of pyogenic pneumococcal meningitis positive either by culture (N = 87) or PCR (N = 35) were positive by ICT, yielding 100% (122 of 122) sensitivity. All purulent CSF specimens from patients with meningitis caused by other bacteria by culture (N = 149) or by LAT (N = 48) or those negative by culture, LAT and LytA and thus of unknown etiology (N = 20), and normal CSF specimens (N = 104) were negative by ICT. Thus the specificity of ICT also was 100% (321 of 321), although negativity of ICT was not confirmed by PCR, if it was positive for other organisms either by culture or LAT. Serotyping of S. pneumoniae strains revealed 28 different serotypes, indicating that outcome of ICT are independent of diverse capsular serotype of pneumococcus. Antigen was detected by ICT for at least 10 days after presentation, and 1 was still positive on day 20, which was longer than for either LAT or PCR.

INTERPRETATION

ICT for pneumococcal antigen in CSF is 100% sensitive and specific in diagnosing pyogenic pneumococcal meningitis and can detect approximately 30% more pneumococcal meningitis cases than with culture alone. The simplicity of the test procedure and the longevity of CSF antigen detection suggest the potential utility of ICT to estimate the true burden of pneumococcal disease, as for Haemophilus influenzae type b using data from meningitis, and to guide selection of appropriate antibiotic treatment, especially in resource-poor countries with widespread prehospital antimicrobial use.

The Impact of a 9-Valent Pneumococcal Conjugate Vaccine on the Public Health Burden of Pneumonia in HIV-Infected and -Uninfected Children

INTRODUCTION

Pneumococcal conjugate vaccine (PnCV) may be used as a probe to define the burden of pneumococcal disease and better characterize the clinical presentation of pneumococcal pneumonia.

METHODS

This study used a 9-valent PnCV to define different end points of vaccine efficacy and the preventable burden of pneumococcal pneumonia in 39,836 children who were randomized in a double-blind, placebo-controlled trial in South Africa.

RESULTS

Whereas the point-estimate of vaccine efficacy was greatest when measured against the outcome of vaccine-serotype specific pneumococcal bacteremic pneumonia (61%; P = .01), the sensitivity of blood culture to measure the burden of pneumococcal pneumonia prevented by vaccination was only 2.6% in human immunodeficiency virus (HIV)-uninfected children and 18.8% in HIV-infected children. Only 37.8% of cases of pneumococcal pneumonia prevented by PnCV were detected by means of chest radiographs showing alveolar consolidation. A clinical diagnosis of pneumonia provided the best estimate of the burden of pneumococcal pneumonia prevented through vaccination in HIV-uninfected children (267 cases prevented per 100,000 child-years) and HIV-infected children (2573 cases prevented per 100,000 child-years).

CONCLUSION

Although outcome measures with high specificity, such as bacteremic pneumococcal pneumonia, provide a better estimate as to vaccine efficacy, the burden of disease prevented by vaccination is best evaluated using outcome measures with high sensitivity, such as a clinical diagnosis of pneumonia.

Concurrent bacterial infection and prolonged mechanical ventilation in infants with respiratory syncytial virus lower respiratory tract disease

OBJECTIVE

To identify demographic, clinical, and laboratory variables predictive for a concurrent bacterial pulmonary infection in ventilated infants with respiratory syncytial virus (RSV) lower respiratory tract disease (LRTD) and investigate antimicrobial drug use.

DESIGN AND SETTING

Retrospective, observational study in a 14-bed pediatric intensive care unit.

PATIENTS

82 infants younger than 1 year of age with a virologically confirmed RSV LRTD during 1996-2001, of whom 65 were mechanically ventilated.

RESULTS

Microbiological data were available from 38 ventilated infants, 10 of whom had a positive blood culture (n=1) or endotracheal aspirate (n=9) obtained upon admission to the pediatric intensive care unit (PICU). Infants with a positive culture had a lower mean gestational age but were otherwise demographically comparable to those with negative culture results. Infants with a positive culture were ventilated 4 days longer. Indicators for a concurrent bacterial infection were comparable between ventilated and nonventilated infants. Antimicrobial drugs were used in 95.1% of infants (100% of ventilated infants) with a mean duration of 7.8+/-0.3 days. The moment of initiation and duration of antimicrobial drug treatment varied considerably.

CONCLUSIONS

We observed in ventilated infants a low occurrence of concurrent bacterial pulmonary infection, but infants with positive cultures needed prolonged ventilatory support. Improvement in the diagnosis of a pulmonary bacterial infection is warranted to reduce the overuse of antimicrobial drugs among ventilated infants with RSV LRTD and to restrict these drugs to the proper patients.

Use of procalcitonin and C-reactive protein to evaluate vaccine efficacy against pneumonia

BACKGROUND

Pneumonia remains the leading cause of death in young children. The poor specificity of chest radiographs (CXRs) to diagnose pneumococcal pneumonia may underestimate the efficacy of pneumococcal conjugate vaccine in preventing pneumococcal pneumonia.

METHODS AND FINDINGS

The efficacy of nine-valent pneumococcal conjugate vaccine among children not infected with HIV (21%; 95% confidence interval, 1%-37%) increased when CXR-confirmed pneumonia was associated with serum C-reactive protein of 120 mg/l (12 mg/dl) or more and procalcitonin of 5.0 ng/ml or more (64%; 95% confidence interval, 23%-83%). Similar results were observed in children infected with HIV.

CONCLUSION

C-reactive protein and procalcitonin improve the specificity of CXR to diagnose pneumococcal pneumonia and may be useful for the future evaluation of the effectiveness of pneumococcal conjugate vaccine in preventing pneumococcal pneumonia.

A vaccine against coccidioidomycosis is justified and attainable

Coccidioides is a fungal pathogen of humans which can cause a life-threatening respiratory disease in immunocompetent individuals. Recurrent epidemics of coccidioidal infections in Southwestern United States has raised the specter of awareness of this soil-borne microbe, particularly among residents of Arizona and Southern California, and has galvanized research efforts to develop a human vaccine against coccidioidomycosis. In this review, we discuss the rationale for such a vaccine, examine the features of host innate and acquired immune response to Coccidioides infection, describe strategies used to identify and evaluate vaccine candidates, and provide an update on progress toward development of a vaccine against this endemic pathogen.

Antigen detection for the diagnosis of pneumonia

Streptococcus pneumoniae and Haemophilus influenzae type b are the main agents of bacterial community-acquired pneumonia in developing countries, although a definite etiologic diagnosis cannot be established in most cases. This study was carried out to assess the performance of a latex particle agglutination test (LPAT) from a commercial kit (Slidex Méningite Kit trade mark, BioMérieux, France) in diagnosing pneumococcal and H. influenzae type b pneumonia. One hundred and seven children (45 ill subjects and 62 healthy controls) were enrolled. All 45 cases had a presumptive diagnosis of bacterial pneumonia based on clinical (WHO criteria), laboratory (white blood cell count > or = 15.000/mm3, polymorphonuclear leukocytes > or = 70%, bands > or = 500/mm3, and C-reactive protein > or = 40 mg/l), and radiological findings, i.e., two or more positive points in the scoring system described by Khamapirad and Glezen (Semin Respir Infect 1987;2:130-144). Clinical, laboratory, and radiological assessments were performed in a blinded manner. LPAT was performed in urine samples after concentration through an ethanol-acetone solution. Sensitivity, specificity, and positive and negative predictive values were 77.3% (95% CI, 61.8-88.0%), 90.3% (95% CI, 79.5-96.0%), 85.0% (95% CI, 69.5-93.8%), and 84.8% (95% CI, 73.4-92.1%), respectively. Results suggest that LPAT is a useful diagnostic tool for the etiologic diagnosis of S. pneumoniae and H. influenzae type b pneumonia, especially in the developing world.

Antimicrobial resistance among pediatric respiratory tract infections: clinical challenges

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

Global reduction of Hib disease: what are the next steps? Proceedings of the meeting Scottsdale, Arizona, September 22-25, 2002

On September 22 to 25, 2002, a group of infectious disease specialists, public health officials, and vaccine experts from 33 countries gathered in Scottsdale, Arizona, to discuss the epidemiology and control of disease caused by Haemophilus influenzae type b (Hib) in the era of Hib conjugate vaccines. This supplement is a synthesis of the major themes and key lessons identified at the meeting. The objectives of the conference were to review the 10-year experience with Hib conjugate vaccines, discuss strategies to reduce Hib disease rates to lowest possible levels in industrialized countries, review impediments to the introduction of Hib vaccine in developing countries, and discuss strategies for disseminating lessons learned from countries using to those not using Hib conjugate vaccines. Over 10 years of international experience with Hib conjugate vaccines has demonstrated that they are safe and effective. Routine use of Hib conjugate vaccine has consistently led to decreases in the incidence of invasive Hib disease of 90% or more across a wide range of epidemiologic situations in industrialized countries. In some countries, the vaccine has caused a near-disappearance of invasive Hib disease through a combination of direct protection and herd immunity. Developing countries that have implemented routine vaccination (eg, The Gambia, Chile) have also had substantial disease reduction. In countries where Hib conjugate vaccine is being used, reducing Hib disease incidence to the lowest possible level will depend on maintaining high vaccine coverage levels, conducting surveillance for Hib disease, and investigating Hib disease cases. The optimal Hib vaccination strategy will depend on many factors, including local epidemiology and programmatic considerations. In countries that are not using Hib conjugate vaccine, information on the local burden of Hib disease will be essential for leaders considering vaccine introduction. Where disease burden is high, a multifaceted approach is urgently needed to evaluate and overcome barriers to vaccine introduction. In areas where Hib disease burden is not well characterized, additional work will be needed to understand the epidemiology of Hib disease and to communicate the value of Hib conjugate vaccine.

Paediatric community-acquired pneumonia: current concept in pharmacological control

Community-acquired pneumonia (CAP) is one of the most frequent infections in childhood but it is not easy to establish a rational therapeutic approach for a number of reasons, including difficulties in identifying the aetiology, the fact that the most frequent bacterial pathogens become resistant to commonly used antibiotics and the lack of certain information concerning the possible preventive role of conjugate vaccines. This leads paediatricians to treat almost all cases of CAP with antibiotics, often using a combination of different antimicrobial classes. In order to avoid unnecessary antibiotic use and limit the spread of antibiotic resistance, consensus guidelines for the management of CAP in childhood should be developed and used by practitioners in their offices and hospitals.