Increase in fitness of Streptococcus pneumoniae is associated with the severity of necrotizing pneumonia

Elixhauser comorbidity method in predicting death of Spanish inpatients with asplenia and pneumococcal pneumonia

BACKGROUND

Pneumococcal pneumonia (PP) is a serious infection caused by Streptococcus pneumoniae (pneumococcus), with a wide spectrum of clinical manifestations. The aim of this study was to analyze the comorbidity factors that influenced the mortality in patients with asplenia according to PP.

METHODS

Discharge reports from the Spanish Minimum Basic Data Set (MBDS) was used to retrospectively analyze patients with asplenia and PP, from 1997 to 2021. Elixhauser Comorbidity Index (ECI) was calculated to predict in-hospital mortality (IHM).

RESULTS

97,922 patients with asplenia were included and 381 cases of PP were identified. The average age for men was 63.87 years and for women 65.99 years. In all years, ECI was larger for splenectomized than for non-splenectomized patients, with men having a higher mean ECI than women. An association was found between risk factors ECI, splenectomy, age group, sex, pneumococcal pneumonia, and increased mortality (OR = 0.98; 95% CI: 0.97-0.99; p < 0.001). The IHM increased steadily with the number of comorbidities and index scores in 1997-2021.

CONCLUSIONS

Asplenia remain a relevant cause of hospitalization in Spain. Comorbidities reflected a great impact in patients with asplenia and PP, which would mean higher risk of mortality.

Necrotizing Pneumonia in Children: Early Recognition and Management

Necrotizing pneumonia (NP) is an uncommon complicated pneumonia with an increasing incidence. Early recognition and timely management can bring excellent outcomes. The diagnosis of NP depends on chest computed tomography, which has radiation damage and may miss the optimal treatment time. The present review aimed to elaborate on the reported predictors for NP. The possible pathogenesis of Streptococcus pneumoniae, Staphylococcus aureus, Mycoplasma pneumoniae and coinfection, clinical manifestations and management were also discussed. Although there is still a long way for these predictors to be used in clinical, it is necessary to investigate early predictors for NP in children.

Development of a Nomogram for Predicting Massive Necrotizing Pneumonia in Children

Objective

This study aimed to develop a nomogram model for predicting massive necrotizing pneumonia (NP) in children.

Methods

A total of 282 children with NP admitted to Kunming Children's Hospital from January 2014 to November 2022 were enrolled. The children with NP were divided into massive necrotizing pneumonia (MNP) group and non-MNP group according to the severity of the lung necrosis. The clinical data of the children were collected, and least absolute shrinkage and selection operator (LASSO) regression and multivariate logistic regression models were used to analyze the influencing factors of MNP. A nomogram model was constructed, and its predictive efficacy was evaluated.

Results

The predictors selected by LASSO regression analysis were: haematogenous spread, white blood cell (WBC), hemoglobin (Hb), C-reactive protein (CRP), lactate dehydrogenase (LDH), and activated partial thromboplastin time (APTT) (P < 0.05). Based on the above independent influencing factors, a nomogram model for MNP was constructed. The bootstrap method was used to repeat sampling 1000 times. The results showed that the consistency index of the nomogram model in predicting MNP was 0.833 in the training set and 0.810 in the validation set. The results of ROC curve analysis showed that the area under the receiver-operating-characteristic curve (AUC) of the nomogram model for predicting MNP was 0.889 [95% CI (0.818, 0.959)] in the training set and 0.814 [95% CI (0.754, 0.874)] in the validation set. The calibration curve of the nomogram predicting MNP was basically close to the actual curve. The decision curve showed that the nomogram had good clinical utility.

Conclusion

We developed a nomogram for predicting MNP, which can help clinicians identify the severity of lung necrosis early.

Early predictors of lung necrosis severity in children with community-acquired necrotizing pneumonia

OBJECTIVE

To analyze baseline clinical and laboratory characteristics and explore the possible predictors of lung necrosis severity in children with community-acquired necrotizing pneumonia (NP).

METHODOLOGY

This retrospective observational study was performed in a tertiary referral center. A total of 104 patients aged <15 years with community-acquired pneumonia and radiologically confirmed NP by computed tomography (CT) were included. Patients were classified into the mild, moderate, or massive necrosis groups.

RESULTS

Among them, 29, 41, and 34 patients had mild, moderate, and massive necrosis, respectively. Moreover, 34.6% of the patients were admitted to pediatric intensive care unit. Massive necrosis was more likely to occur during winter (p < 0.05) and was associated with more severe clinical outcomes, such as longer duration of fever, longer hospitalization, increased mortality, and a higher risk of subsequent surgical intervention (p < 0.05). Multivariate analysis demonstrated that the following were independent risk factors for massive necrosis in this study: C-reactive protein (CRP) (p = 0.036), serum albumin (p = 0.009), and immunoglobulin M (IgM) (p = 0.022). Receiver operating characteristic analysis showed that when the cut-off value for CRP, serum albumin, and IgM were set at 122 mg/L, 30.8 g/L, and 95.7 mg/dl, respectively, they showed good diagnostic performance for differentiating patients with massive necrosis from all patients with NP.

CONCLUSION

NP is a potentially severe complication of pediatric community-acquired pneumonia. Different severities of lung necrosis can lead to different clinical outcomes. CRP, serum albumin, and IgM levels are independent predictors of the degree of lung necrosis.

Necrotizing pneumonia due to Streptococcus pneumoniae in children during the period of non-systematic use of PCV13 in Catalonia, Spain

BACKGROUND

Some studies have observed an increased incidence of necrotizing pneumonia (NP) in recent years. This might be related to the emergence of non-vaccine S. pneumoniae serotypes after PCV7 introduction although it is suggested that evolutionary factors may have modified the virulence and the interactions of pneumococci. The aim of this study was to clinically and microbiologically define NP in the population served by the three major paediatric hospitals in Barcelona (Catalonia, Spain).

METHODS

A prospective observational study was conducted in patients <18 years hospitalized due to invasive pneumococcal disease (January 2012-June 2016). Data of confirmed cases of pneumococcal NP (diagnosed by culture or DNA detection and serotyped) were collected. PCV13 was not systematically administered in Catalonia during the study period, but was available in the private market so the vaccination coverage in children increased from 48.2% to 74.5%.

RESULTS

35 cases of NP were identified. 77.1% of cases were associated with empyema. In the first 4 years, a trend to a decrease in NP incidence was observed (p=0.021), especially in children <5 years (p=0.006). Serotype 3 was responsible for 48.6% of NP cases. Five patients with NP due to serotype 3 were fully vaccinated for their age with PCV13.

CONCLUSIONS

Serotype 3 has a preeminent role in pneumococcal NP and was associated with all PCV13 vaccination failures. Although in our series the incidence does not seem to be increasing, evolution of pneumococcal NP rates should be monitored after inclusion of PCV13 in the systematic calendar.

Long-term outcomes of necrotizing pneumonia

INTRODUCTION

Necrotizing pneumonia (NP) is a serious complication of community-acquired pneumonia characterised by the destruction of normal lung parenchyma. No study has evaluated the repercussions of the lung damage in the years following the episode. The aim of this study was to assess the long-term impact on lung function and respiratory symptoms in children hospitalised due to NP.

METHODS

We analysed outcomes in children given a diagnosis of NP between January 2003 and April 2016. We selected patients aged more than 4 years capable of undergoing a lung function test, that had been followed up for at least 2 years. The patients completed a respiratory questionnaire and underwent a lung function test.

RESULTS

We included a total of 24 patients (12 male). The median age at the time of diagnosis was 28 months, the median length of stay was 15 days, and 18 patients required pleural drainage. The mean duration of follow-up after NP was 8.75 years. During the evaluation, none of the patients exhibited asthma, cough, or exercise-induced symptoms. Three children had a second episode of pneumonia that did not require hospital admission. The spirometry results were the following (given as mean±standard deviation): FEV1 Z-score, -0.47±0.65; FVC Z-score, -0.56±0.73; and FEV1/FVC Z-score, 0.19±0.98. We found no evidence of obstructive pulmonary disease or restrictive patterns.

CONCLUSIONS

The long-term outcomes of paediatric NP are good. However, patients exhibited mildly impaired lung function several years after the episode. We recommend follow-up of these patients due to potential impairments in lung function in adulthood.

Genomic Insight into the Spread of Meropenem-Resistant Streptococcus pneumoniae Spain23F-ST81, Taiwan

Incidence of invasive pneumococcal disease caused by antimicrobial-resistant Streptococcus pneumoniae types not included in pneumococcal conjugate vaccines has increased, including a penicillin- and meropenem-resistant serotype 15A-ST63 clone in Japan. During 2013-2017, we collected 206 invasive pneumococcal isolates in Taiwan for penicillin and meropenem susceptibility testing. We found serotypes 15B/C-ST83 and 15A-ST63 were the most prevalent penicillin- and meropenem-resistant clones. A transformation study confirmed that penicillin-binding protein (PBP) 2b was the primary meropenem resistance determinant, and PBP1a was essential for high-level resistance. The rate of serotype 15B/C-ST83 increased during the study. All 15B/C-ST83 isolates showed an ermB macrolide resistance genotype. Prediction analysis of recombination sites revealed 12 recombination regions in 15B/C-ST83 compared with the S. pneumoniae Spain^23F-ST81 genome. Pneumococcal clones rapidly recombine to acquire survival advantages and undergo local expansion under the selective pressure exerted by vaccines and antimicrobial drugs. The spread of 15B/C-ST83 is alarming for countries with high antimicrobial pressure.

Necrotizing pneumonia among Italian children in the pneumococcal conjugate vaccine era

BACKGROUND

Necrotizing pneumonia (NP) is a severe complication of community-acquired pneumonia. The impact of 13-valent pneumococcal conjugate vaccine (PCV13) on the epidemiology of NP in children has not been assessed.

PATIENTS AND METHODS

Medical records of children less than 18 years admitted with NP to two pediatric hospitals in Italy between 2005 and 2019 were reviewed. The following four periods were defined: 2005-2010 (pre-PCV13), 2011-2013 (early post-PCV13), 2014-2016 (intermediate post-PCV13), and 2017-2019 (late post-PCV13).

RESULTS

Forty-three children (median age, 44 months) were included. Most of them (93%) were previously healthy. No differences in age, sex, season of admission, comorbidity, clinical presentation, or hospital course were identified between pre-PCV13 and post-PCV13 periods. A significant decrease in the rate of NP-associated hospitalizations was found between the early (1.5/1000 admissions/year) and the intermediate (0.35/1000 admissions/year) post-PCV13 period (p = .001). An increased trend in admissions was found thereafter. Streptococcus pneumoniae was the most common agent detected in both periods (pre-PCV13: 11/18, 61%; post-PCV13: 13/25, 52%). Serotype 3 was the most common strain in both periods (pre-PCV13: 3/11, 27%; post-PCV13; 4/13, 31%). There were no changes in the etiology over time, but most patients with Streptococcus pyogenes or Staphylococcus aureus infection were admitted during the post-PCV13 period.

CONCLUSIONS

The hospitalization rate for NP in children decreased a few years after the implementation of PCV13 immunization in Italy. However, an increased trend in admissions was found thereafter. S. pneumoniae was the most frequent causal agent in both pre- and post-PCV13 periods. Pneumococcal serotypes were mainly represented by Strain 3.

Adhesion molecules as diagnostic and severity biomarkers in pediatric community-acquired pneumonia

BACKGROUND

Discrimination of the cases with severe and mild pneumonia is crucial due to the requirement of hospitalization, additional management, and treatment protocols. We aimed to analyze the role of IL6 (Interleukin), IL8, IL10, VCAM-1 (soluble Vascular Cell Adhesion Molecule), and sSELE (soluble E-selectin) in the diagnosis and prognostic evaluation of community-acquired pneumonia (CAP).

METHODS

Pediatric patients with severe pneumonia (SP) were hospitalized and patients with mild disease (MP) were treated in the community. IL6, IL8, IL10, VCAM-1, and sSELE levels of the patients were investigated and compared with the age- and gender-matched healthy subjects.

RESULTS

A total of 113 patients fulfilling the criteria for a diagnosis of CAP were enrolled in the study, 62 (54.8%) of which had SP and 51 (45%) had MP. MP and SP groups were significantly different in terms of IL8, IL10, and sSELE levels. Patients with SP and MP had significantly different WBC, ESR, and CRP values, as well.

CONCLUSIONS

Besides classical acute phase parameters, inflammatory response parameters such as IL6 and VCAM-1 levels may be helpful in diagnosis of pneumonia. In terms of determination of disease severity in pediatric CAP, systemic inflammatory markers like IL8 and IL10 and adhesion molecules like sSELE seem useful in clinical settings.

Emergent Pneumonia in Children

In recent decades there have been multiple pathogens, viruses and bacteria, which have emerged as causal agents of pneumonia affecting adults, albeit less frequently, to children. For the purposes of this article we have classified emerging pathogens as follows: True emerging, to pathogens identified for the very first time affecting human population (SARS-CoV-1, SARS-CoV-2, MERS-CoV, avian influenza, and hantavirus); Re-emerging, to known pathogens which circulation was controlled once, but they have reappeared (measles, tuberculosis, antimicrobial resistant bacteria such as CA-MRSA, Mycoplasma pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Stenotrophomonas maltophilia, and new serotypes of post-vaccine pneumococcal); and finally, those that we have called old known with new presentations, including common pathogens that, in particular condition, have changed their form of presentation (rhinovirus, and non-SARS coronavirus). We will review for each of them their epidemiology, forms of presentation, therapy, and prognosis in children compared to the adult with the aim of being able to recognize them to establish appropriate therapy, prognostics, and effective control measures.

Necrotizing pneumonia due to Streptococcus pneumoniae in children during the period of non-systematic use of PCV13 in Catalonia, Spain

BACKGROUND

Some studies have observed an increased incidence of necrotizing pneumonia (NP) in recent years. This might be related to the emergence of non-vaccine S. pneumoniae serotypes after PCV7 introduction although it is suggested that evolutionary factors may have modified the virulence and the interactions of pneumococci. The aim of this study was to clinically and microbiologically define NP in the population served by the three major paediatric hospitals in Barcelona (Catalonia, Spain).

METHODS

A prospective observational study was conducted in patients <18 years hospitalized due to invasive pneumococcal disease (January 2012-June 2016). Data of confirmed cases of pneumococcal NP (diagnosed by culture or DNA detection and serotyped) were collected. PCV13 was not systematically administered in Catalonia during the study period, but was available in the private market so the vaccination coverage in children increased from 48.2% to 74.5%.

RESULTS

35 cases of NP were identified. 77.1% of cases were associated with empyema. In the first 4 years, a trend to a decrease in NP incidence was observed (p=0.021), especially in children <5 years (p=0.006). Serotype 3 was responsible for 48.6% of NP cases. Five patients with NP due to serotype 3 were fully vaccinated for their age with PCV13.

CONCLUSIONS

Serotype 3 has a preeminent role in pneumococcal NP and was associated with all PCV13 vaccination failures. Although in our series the incidence does not seem to be increasing, evolution of pneumococcal NP rates should be monitored after inclusion of PCV13 in the systematic calendar.

[Long-term outcomes of necrotizing pneumonia]

INTRODUCTION

Necrotizing pneumonia (NP) is a serious complication of community-acquired pneumonia characterised by the destruction of normal lung parenchyma. No study has evaluated the repercussions of the lung damage in the years following the episode. The aim of this study was to assess the long-term impact on lung function and respiratory symptoms in children hospitalised due to NP.

METHODS

We analysed outcomes in children given a diagnosis of NP between January 2003 and April 2016. We selected patients aged more than 4 years capable of undergoing a lung function test, that had been followed up for at least 2 years. The patients completed a respiratory questionnaire and underwent a lung function test.

RESULTS

We included a total of 24 patients (12 male). The median age at the time of diagnosis was 28 months, the median length of stay was 15 days, and 18 patients required pleural drainage. The mean duration of follow-up after NP was 8.75 years. During the evaluation, none of the patients exhibited asthma, cough, or exercise-induced symptoms. Three children had a second episode of pneumonia that did not require hospital admission. The spirometry results were the following (given as mean ± standard deviation): FEV1 z-score, -0.47±0.65; FVC z-score, -0.56±0.73; and FEV1/FVC z-score, 0.19±0.98. We found no evidence of obstructive pulmonary disease or restrictive patterns.

CONCLUSIONS

The long-term outcomes of paediatric NP are good. However, patients exhibited mildly impaired lung function several years after the episode. We recommend follow-up of these patients due to potential impairments in lung function in adulthood.

The potential role of pneumococcal conjugate vaccine in reducing acute respiratory inflammation in community-acquired pneumococcal pneumonia

Background

Pneumococcal conjugate vaccine (PCV) reduces both invasive pneumococcal disease (IPD) and other pneumococcal infections worldwide. We investigated the impact of stepwise implementation of childhood PCV programs on the prevalence of pneumococcal pneumonia, severity of acute inflammation, and associations between breakthrough pneumonia and pneumococcal serotypes in Taiwan.

Methods

In total, 983 children diagnosed with community-acquired pneumococcal pneumonia were enrolled between January 2010 and December 2015.

Results

Proportions of pneumococcal vaccinations increased each year in age-stratified groups with PCV7 (32.2%) as the majority, followed by PCV13 (12.2%). The proportion of pneumococcal pneumonia decreased each year in age-stratified groups, especially in 2–5 year group. Serotype 19A is the leading serotype either in vaccinated (6.4%) or unvaccinated patients (5.2%). In particular, vaccinated patients had significantly higher lowest WBC, lower neutrophils, lower lymphocytes and lower CRP values than non-vaccinated patients (p < 0.05). After stratifying patients by breakthrough infection, those with breakthrough pneumococcal infection with vaccine coverage serotypes had more severe pneumonia disease (p < 0.05).

Conclusion

Systematic childhood pneumococcal vaccination reduced the prevalence of community-acquired pneumococcal pneumonia, especially in 2–5 year group. Serotype 19A was the major serotype for all vaccine types in patients with pneumococcal pneumonia and severity of acute inflammatory response was reduced in vaccinated patients.

Influenza virus infection complicated by bacterial necrotising pneumonia: two case reports

Necrotising pneumonia (NP) is a potentially severe complication of community-acquired pneumonia characterised by necrosis of consolidated lung tissue. A 7-year-old boy and a 6-year-old boy are presented, both of whom had a complicated influenza infection which evolved into severe NP caused by Streptococcus pneumoniae. Both needed intensive care for invasive respiratory support. Despite extensive pleural involvement in both cases, only one required thoracic surgery. Case 1 also developed anaemia, hyponatraemia and hypo-albuminaemia, resulting in generalised oedema. Despite the severe morbidity, both boys made a full recovery. The diagnosis of NP should always be considered in a child with pneumonia who remains unwell despite 72 hours of appropriate antibiotics, particularly if there is evidence of pleural disease. Although S. pneumoniae is the main agent for NP, the influenza virus may be a precipitating factor.

Characteristics and etiology of hospitalized pediatric community-acquired pneumonia in Taiwan

Background/purpose

The purpose of this study was to determine the pathogens and to estimate the incidence of pediatric community-acquired pneumonia (CAP) in Taiwan.

Methods

This prospective study was conducted at eight medical centers from November 2010 to September 2013. Children aged 6 weeks to 18 years who met the radiologic criteria for pneumonia were enrolled. To detect classical and atypical bacteria and viruses, blood and pleural fluids were cultured, and respiratory specimens were examined by multiple conventional and molecular methods.

Results

At least one potential pathogen was identified in 705 (68.3%) cases of 1032 children enrolled, including bacteria in 420 (40.7%) cases, virus in 180 (17.4%) cases, and mixed viral-bacterial infection in 105 (10.2%) cases. Streptococcus pneumoniae (31.6%) was the most common pathogen, followed by Mycoplasma pneumoniae (22.6%). Adenovirus (5.9%) was the most common virus. RSV was significantly associated with children aged under 2 years, S. pneumoniae in children aged between 2 and 5 years, and M. pneumoniae in children aged >5 years. The annual incidence rate of hospitalization for CAP was highest in children aged 2–5 years (229.7 per 100,000). From 2011 to 2012, significant reduction in hospitalization rates pertained in children under 5 years of age, in pneumonia caused by pneumococcus, adenovirus or co-infections and complicated pneumonia.

Conclusion

CAP related pathogens have changed after increased conjugated pneumococcal vaccination rates. This study described the latest incidences and trends of CAP pathogens, which are crucial for prompt delivery of appropriate therapy.

Retrospective Study in Children With Necrotizing Pneumonia: Nine Years of Intensive Care Experience

BACKGROUND

Although necrotizing pneumonia (NN) is one of the most feared complications of community-acquired pneumonia, data in pediatric patients are scarce. The objective of this article is to describe children admitted to pediatric intensive care unit (PICU) because of NN.

METHODS

Retrospective-prospective observational study in children admitted with NN to PICU (from January 1, 2010, to December 31, 2018). The data collected included information on disease epidemiology, PICU management, respiratory assistance and disease evolution.

RESULTS

Fifty-one children were included, 42 of 51 had received 7-valent or 13-valent pneumococcal vaccine. Median age was 3.2 years (1.9-4.2), 15 of 51 had signs of sepsis at admission. Forty-nine patients presented pleural effusion with drainage in 46. The most common respiratory support modality was high-flow oxygen nasal cannula (17/51). Computed tomography was the gold standard for diagnosis. Etiologic diagnosis was obtained in 34 of 51, and pneumococcus was isolated in 29 of 34. In all of these cases, initial detection was made by capsular antigen in pleural fluid. Children with pneumococcal NN had fewer days of evolution prior to PICU admission (P = 0.041). Cefotaxime with clindamycin was used in 49 of 51. Surgery was necessary in 3 of 51 patients. After PICU discharge, only 5 of 51 were readmitted. There were deaths.

CONCLUSIONS

In our study, the NN was mainly observed in children around 3 years old. The main causal agent was pneumococcus. The evolution towards NN appeared to be faster than in case of other etiologies. Surgery management was unusual. All children required prolonged admissions but had a full clinical recovery.

Factors Associated With Pneumonia Severity in Children: A Systematic Review

Community-acquired pneumonia in children is associated with significant morbidity and mortality; however, data are limited in predicting which children will have negative outcomes, including clinical deterioration, severe disease, or development of complications. The Pediatric Infectious Diseases Society/Infectious Diseases Society of America (PIDS/IDSA) pediatric pneumonia guideline includes criteria that were modified from adult criteria and define pneumonia severity to assist with resource allocation and site-of-care decision-making. However, the PIDS/IDSA criteria have not been formally developed or validated in children. Definitions for mild, moderate, and severe pneumonia also vary across the literature, further complicating the development of standardized severity criteria. This systematic review summarizes (1) the current state of the evidence for defining and predicting pneumonia severity in children as well as (2) emerging evidence focused on risk stratification of children with pneumonia.

Invasive pneumococcal disease in Northern Alberta, not a Red Queen but a dark horse

BACKGROUND

The consequences of the introduction of various pneumococcal protein conjugate vaccines (PCV) for children and adults is poorly understood.

OBJECTIVE

We undertook a population-based cohort study of invasive pneumococcal disease (IPD) in Northern Alberta (Canada) from 2000 to 2014, years spanning pre-and early PCV (2000-2004) vs PCV-7 (2005-2009) vs PCV-13 (2010-2014) time periods.

DESIGN

We collected clinical, laboratory, and Streptococcus pneumoniae serotype information on all patients from 2000 to 2014. We determined changes in presentation, outcomes, serotypes, and incidence in children and adults across time periods.

SETTING

There were 509 cases of IPD in children, an 80% decrease over time. Rates of empyema (4.0-15.7%, p < 0.001), ICU admission (13.1-20%), and mortality (1.8-8.4%, p < 0.001) increased over time. There were 2417 cases of IPD in adults. Unlike children, incidence of IPD did not change nor did rates of empyema. ICU admissions increased (p = 0.004) and mortality decreased (18.7-16.5%, p = 0.002). The total number of serotypes causing IPD remained stable in children (22 vs 26 vs 20) while they decreased in adults (49 vs 47 vs 42).

CONCLUSIONS AND RELEVANCE

For children, PCV vaccination strategies resulted in decreased overall rates of IPD and we observed increased rates of empyema and mortality; for adults, there was no change in IPD rates although disease severity increased while mortality decreased. On a population-wide basis, our results suggest that current PCV vaccination strategies are associated with an overall decrease in IPD but disease severity seems to be increasing in both children and adults.

Invasive pneumococcal pneumonia caused by 13-valent pneumococcal conjugate vaccine types in children with different schedules

BACKGROUND

In Taiwan, the age group with the greatest incidence of invasive pneumococcal disease is 2-5 years of age, which is different from other countries. This study was conducted to identify risk factors and different 13-valent pneumococcal conjugate vaccine (PCV13) schedules associated with vaccine-type invasive pneumococcal pneumonia (IPP) despite prior vaccination.

METHODS

A case-control study was conducted prospectively between August 2012 and December 2015 at five participating medical centers. The study enrolled children <15 years of age who were admitted to one of the five medical centers for CAP. Blood samples and acute-phase serum specimens were collected and Streptococcus pneumoniae was identified by using a real-time polymerase-chain-reaction (RT-PCR) assay targeting the lytA gene.

RESULTS

A total of 25 children diagnosed with vaccine-type IPP and 124 controls were enrolled. Vaccine-type IPP occurred in 6 (28.6%), 14 (24.1%), and 5 (7.1%) children receiving vaccines on a not-age-appropriate schedule (n = 21), primary infant schedule (n = 58), and toddler catch-up schedule (n = 70) (P = 0.008), respectively. Of 25 children, the mean age at disease onset was 36 ± 11 months; serotype 19A was responsible for 84% (21/25).

CONCLUSION

After adjustment for confounding factors, the risk of vaccine-type IPP was significantly higher among children receiving vaccines on a not-age-appropriate schedule, or on a primary infant schedule, compared with children receiving vaccines on a toddler catch-up schedule. Duration of vaccine immunity should be investigated to direct strategies for maintaining individual and population immunity against pneumococcal disease.

Necrotizing pneumonia: an emerging problem in children?

BACKGROUND

In children, necrotizing pneumonia (NP) is an uncommon, severe complication of pneumonia. It is characterized by destruction of the underlying lung parenchyma resulting in multiple small, thin-walled cavities and is often accompanied by empyema and bronchopleural fistulae.

REVIEW

NP in children was first reported in children in 1994, and since then there has been a gradual increase in cases, which is partially explained by greater physician awareness and use of contrast computed tomography (CT) scans, and by temporal changes in circulating respiratory pathogens and antibiotic prescribing. The most common pathogens detected in children with NP are pneumococci and Staphylococcus aureus. The underlying disease mechanisms are poorly understood, but likely relate to multiple host susceptibility and bacterial virulence factors, with viral-bacterial interactions also possibly having a role. Most cases are in previously healthy young children who, despite adequate antibiotic therapy for bacterial pneumonia, remain febrile and unwell. Many also have evidence of pleural effusion, empyema, or pyopneumothorax, which has undergone drainage or surgical intervention without clinical improvement. The diagnosis is generally made by chest imaging, with CT scans being the most sensitive, showing loss of normal pulmonary architecture, decreased parenchymal enhancement and multiple thin-walled cavities. Blood culture and culture and molecular testing of pleural fluid provide a microbiologic diagnosis in as many as 50% of cases. Prolonged antibiotics, draining pleural fluid and gas that causes mass effects, and maintaining ventilation, circulation, nutrition, fluid, and electrolyte balance are critical components of therapy. Despite its serious nature, death is uncommon, with good clinical, radiographic and functional recovery achieved in the 5-6 months following diagnosis. Increased knowledge of NP's pathogenesis will assist more rapid diagnosis and improve treatment and, ultimately, prevention.

CONCLUSION

It is important to consider that our understanding of NP is limited to individual case reports or small case series, and treatment data from randomized-controlled trials are lacking. Furthermore, case series are retrospective and usually confined to single centers. Consequently, these studies may not be representative of patients in other locations, especially when allowing for temporal changes in pathogen behaviour and differences in immunization schedules and antibiotic prescribing practices.

Relevant Cytokines in the Management of Community-Acquired Pneumonia

Community-acquired pneumonia (CAP) is the leading cause of infectious death in the world. Immune dysregulation during acute lung infection plays a role in lung injury and the systemic inflammatory response. Cytokines seem to be major players in severe lung infection cases. Here, we present a review of published papers in the last 3 years regarding this topic. The cytokine response during pneumonia is different in bacterial vs viral infections; some of these cytokines correlate with clinical severity scales such as CURB65 or SOFA. Treatment focused in the cytokine environment is an interesting area that could impact the prognosis of CAP. Some of the agents that have been studied as co-adjuvant therapy are corticosteroids, macrolides, and linezolid, but anyone of those have shown a clear or proven efficacy or have been recommended as a part of the standard of care for CAP. More studies designed to define the role of immunomodulatory agents, such as co-adjuvant therapy in pneumonia, are needed.

Reduced IL-17A Secretion Is Associated with High Levels of Pneumococcal Nasopharyngeal Carriage in Fijian Children

Streptococcus pneumonia (the pneumococcus) is the leading vaccine preventable cause of serious infections in infants under 5 years of age. The major correlate of protection for pneumococcal infections is serotype-specific IgG antibody. More recently, antibody-independent mechanisms of protection have also been identified. Preclinical studies have found that IL-17 secreting CD4+ Th17 cells in reducing pneumococcal colonisation. This study assessed IL-17A levels in children from Fiji with high and low pneumococcal carriage density, as measured by quantitative real-time PCR (qPCR). We studied Th17 responses in 54 children who were designated as high density carriers (N=27, >8.21x10⁵ CFU/ml) or low density carriers (N=27, <1.67x10⁵ CFU/ml). Blood samples were collected, and isolated peripheral blood mononuclear cells (PBMCs) were stimulated for 6 days. Supernatants were harvested for cytokine analysis by multiplex bead array and/or ELISA. Th17 cytokines assayed included IL-17A, IL-21, IL-22 as well as TNF-α, IL-10, TGF-β, IL-6, IL-23 and IFNγ. Cytokine levels were significantly lower in children with high density pneumococcal carriage compared with children with low density carriage for IL-17A (p=0.002) and IL-23 (p=0.04). There was a trend towards significance for IL-22 (p=0.057) while no difference was observed for the other cytokines. These data provide further support for the role of Th17-mediated protection in humans and suggest that these cytokines may be important in the defence against pneumococcal carriage.