Necrotizing pneumococcal pneumonia with bronchopleural fistula among children in Taiwan

Genomic analysis of penicillin-binding proteins and recombination events in an emerging amoxicillin- and meropenem-resistant PMEN3 (Spain9V-3, ST156) variant in Taiwan and comparison with global descendants of this lineage

From 2008 to 2020, the Taiwan National Notifiable Disease Surveillance System database demonstrated that the incidence of non-vaccine serotype 23A invasive pneumococcal disease (IPD) approximately doubled. In this study, 276 non-repetitive pneumococcal clinical isolates were collected from two medical centers in Taiwan between 2019 and 2021. Of these 267 pneumococci, 60 were serotype 23A. Among them, 50 (83%) of serotype 23A isolates belonged to the sequence type (ST) 166 variant of the Spain9V-3 clone. Pneumococcal 23A-ST166 isolates were collected to assess their evolutionary relationships using whole-genome sequencing. All 23A-ST166 isolates were resistant to amoxicillin and meropenem, and 96% harbored a novel combination of penicillin-binding proteins (PBPs) (1a:2b:2x):15:11:299, the newly identified PBP2x-299 in Taiwan. Transformation of the pbp1a, pbp2b, and pbp2x alleles into the β-lactam-susceptible R6 strain revealed that PBP2x-299 and PBP2b-11 increased the MIC of ceftriaxone and meropenem by 16-fold, respectively. Prediction analysis of recombination sites in PMEN3 descendants (23A-ST166 in Taiwan, 35B-ST156 in the United States, and 11A-ST838/ST6521 in Europe) showed that adaptive evolution involved repeated, selectively favored convergent recombination in the capsular polysaccharide synthesis region, PBPs, murM, and folP genome sites. In the late 13-valent pneumococcal conjugate vaccine era, PMEN3 continuously displayed an evolutionary capacity for global dissemination and persistence, increasing IPD incidence, leading to an offset in the decrease of pneumococcal conjugate vaccine serotype-related diseases, and contributing to high antibiotic resistance. A clonal shift with a highly β-lactam-resistant non-vaccine serotype 23A, from ST338 to ST166, increased in Taiwan. ST166 is a single-locus variant of the Spain9V-3 clone, which is also called the PMEN3 lineage. All 23A-ST166 isolates, in this study, were resistant to amoxicillin and meropenem, and 96% harbored a novel combination of penicillin-binding proteins (PBPs) (1a:2b:2x):15:11:299. PBP2x-299 and PBP2b-11 contributed to the increasing MIC of ceftriaxone and meropenem, respectively. Prediction analysis of recombination sites in PMEN3 descendants showed that adaptive evolution involved repeated, selectively favored convergent recombination in the capsular polysaccharide synthesis region, PBPs, murM, and folP genome sites. In the late 13-valent pneumococcal conjugate vaccine era, PMEN3 continuously displays the evolutionary capacity for dissemination, leading to an offset in the decrease of pneumococcal conjugate vaccine serotype-related diseases and contributing to high antibiotic resistance.

A pediatric case series of invasive pneumococcal disease caused by S.Pneumonia serotype-19A despite full dose vaccination

Streptococcus pneumoniae is the leading cause of community-acquired pneumonia and bacterial meningitis in children. Although pneumococcal conjugate vaccines (PCVs) are commonly available, invasive pneumococcal disease (IPD) still remains a life-threatening complication. Serotype 19A has high invasive potential and is capable of causing extensive and destructive lung disease. This strain has greater invasive potential, may have a growth advantage over other pneumococcal serotypes in normally sterile sites, and is often resistant to multiple antibiotics. Although being a component of PCV13 vaccine, serotype 19A may still be seen in fully vaccinated children and can cause invasive disease. Herein, we present four cases of IPD caused by S. pneumoniae serotype 19A who received the full regimen of PCV13 vaccination.

A challenging high-risk surgery for necrotizing pneumonia in a right bilobed lung

BACKGROUND

Necrotizing pneumonia is rare in children and is one of the most serious complications of a lung infection caused by antibiotic failure. We present a 12-year-old leukopenic child with a long-lasting lung infection, presenting as having a lung hydatid cyst, but diagnosing with necrotizing pneumonia in the right bilobed lung. Failure to medical treatment and ongoing leukopenia justified surgical intervention with positive results.

CASE PRESENTATION

The patient was referred to our teaching hospital's pediatric surgery department. He had previously been diagnosed with intestinal tuberculosis (TB) and received anti-TB treatment. On referral to our hospital, the patient was suffering from restlessness, frequent coughing, fever, vomiting, and diarrhea. Following the completion of the clinical work-up, a blood test revealed leukopenia (white blood cell count of 2100/microliter), a normal platelet count, and a lesion in the right lung. Computerized tomography scanning (CT-Scan) image reported a lung hydatid cyst. In the pediatrics ward, a broad-spectrum antibiotics regimen with triple-antibiotic therapy (linezolid, vancomycin, and metronidazole) was instituted and continued for a week with no response, but worsening of the condition. In the pediatric surgery ward, our decision for surgical intervention was due to the failure of medical treatment because of a pulmonary lesion. Our team performed right lung upper lobe anterior segment wedge resection due to necrotizing pneumonia and followed the patient 45 days post-operation with a reasonable result.

CONCLUSION

Living in remote rural areas with low resources and inaccessibility to proper and specialized diagnostic and treatment centers will all contribute to an improper diagnosis and treatment of lung infection. In total, all of these will increase the morbidity and mortality due to lung necrosis in the pediatric population, regardless of their age. In low-resource facilities, high-risk patients can benefit from surgical intervention to control the ongoing infection process.

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.

Risk factors for complicated community-acquired pneumonia in children

BACKGROUND

Community-acquired pneumonia (CAP) in children continues to be one of the prominent causes of pediatric morbidity and mortality worldwide. By determining the risk factors associated with the development of complicated CAP (CCAP), new approaches for early diagnosis and effective treatment can be identified.

METHODS

This retrospective cohort study enrolled patients with CAP and CCAP who visited the pediatric ward of the study hospital between January 1, 2017 and December 31, 2017. For patients with CCAP, data regarding medical procedures performed, surgical intervention, and hospitalization duration were collected.

RESULTS

A total of 111 patients, 93 (83.7%) with CAP and 18 (16.3%) with CCAP, aged between 3 months and 18 years were hospitalized because of severe pneumonia. The mean age of the patients was 3.6 ± 1.2 years and 60 (54%) of them were female. The mean age of patients with CCAP was higher than that of patients with CAP (4.2 ± 3.3 vs. 2.8 ± 2.1 years respectively); however, the difference was not significant (p = 0.012). Patients with CCAP exhibited a significantly higher C-reactive protein level than those with CAP (10.06 ± 7.55 vs. 4.43 ± 3.37 g/L respectively; p = 0.007). Hypoxia upon admission was noted more commonly in the CCAP group than in the CAP group (p < 0.001).

CONCLUSION

Findings related to hypoxia, respiratory distress, and pleural effusion on imaging are important distinguishing factors associated with the development of complications in patients hospitalized with CAP. Therefore, CCAP etiology, diagnosis, and treatment approaches should be established and protective measures adopted.

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.

Nonsurgical management of dynamic pneumatocele via endobronchial administration of fibrin sealant

A 12-year-old male was admitted to the Medical Intensive Care Unit for respiratory failure requiring temporary tracheostomy secondary to an extensive necrotizing methicillin-resistant Staphylococcus aureus pneumonia. Imaging revealed destructive bronchiectasis and multifocal lung abscesses, more advanced in the right lung. He was discharged home after 42-day hospital admission. 3.5 months after his discharge, he re-presented to the Emergency Department with a large right pneumothorax and a pneumatocele measuring 10.2 × 6.2 cm² . He was admitted to the hospital and while his pneumothorax resolved in 2 days, the size of the pneumatocele was noted to fluctuate with different phases of respiration. A computed tomography scan of the chest demonstrated a fistula between the pneumatocele and right upper lobe bronchus. Following discussion between Pulmonary medicine and Interventional radiology, transbronchial closure of the air leak was planned. Intubation was done with a dual-lumen endotracheal tube. Bronchography was performed using a diagnostic catheter. A large air leak was noted from the anterior segment of the right upper lobe bronchus. Embolization of the fistula was performed using n-butyl cyanoacrylate (nBCA, glue) injected through a second catheter under fluoroscopic guidance. The residual pneumatocele slowly resolved over 2 months. Endobronchial embolization has been described in the literature as a treatment strategy for air leaks, largely in adult patients. Endobronchial embolization of large pneumatoceles and bronchopleural fistulas may offer an alternative treatment option with less morbidity than the classic surgical approach.

Paediatric pneumonia in high-income countries: Defining and recognising cases at increased risk of severe disease

World Health Organisation definitions of pneumonia severity are routinely used in research. In high income health care settings with high rates of pneumococcal vaccination and low rates of mortality, malnutrition and HIV infection, these definitions are less applicable. National guidelines from leading thoracic and infectious disease societies describe 'severe pneumonia' according to criteria derived from expert consensus rather than a robust evidence base. Contemporary cohort studies have used clinical outcomes such as intensive care therapy or invasive procedures for complicated pneumonia, to define severe disease. Describing severe pneumonia in such clinically relevant terms facilitates the identification of risk factors associated with worsened disease and the subsequently increased morbidity, and need for tertiary level care. The early recognition of children at higher risk of severe pneumonia informs site of care decisions, antibiotic treatment decisions as well as guiding appropriate investigations. Younger age, malnutrition, comorbidities, tachypnoea, and hypoxia have been identified as important associations with 'severe pneumonia' by WHO definition. Most studies have been performed in low-middle income countries and whilst they provide some insight into those at risk of mortality or treatment failure, their generalisability to the high-income setting is limited. There is a need to determine more precise definitions and criteria for severe disease in well-resourced settings and to validate factors associated with intensive care admission or invasive procedures to enhance the early recognition of those at risk.

Persistent pulmonary air leak in the pediatric intensive care unit: Characteristics and outcomes

BACKGROUND

Persistent air leak (PAL) complicates various lung pathologies in children. The clinical characteristics and outcomes of children hospitalized in the pediatric intensive care unit (PICU) with PAL are not well described. We aimed to elucidate the course of disease among PICU hospitalized children with PAL.

METHODS

A retrospective cohort study of all PICU-admitted children aged 0-18 years diagnosed with pneumothorax complicated by PAL, between January 2005 and February 2020 was conducted at a tertiary center. PAL was defined as a continuous air leak of more than 48 h.

RESULTS

PAL complicated the course of 4.8% (38/788) of children hospitalized in the PICU with pneumothorax. Two were excluded due to missing data. Of 36 children included, PAL was secondary to bacterial pneumonia in 56%, acute respiratory distress syndrome (ARDS) in 31%, lung surgery in 11%, and spontaneous pneumothorax in 3%. Compared to non-ARDS causes, children with ARDS required more drains (median, range: 4, 3-11 vs. 2, 1-7; p < .001) and mechanical ventilation (100% vs. 12%; p < .001), and had a higher mortality (64% vs. 0%; p < .001). All children with bacterial pneumonia survived to discharge, with a median air leak duration of 14 days (range 3-72 days). Most of which (90%) were managed conservatively, by continuous chest drainage.

CONCLUSION

Bacterial pneumonia was the leading cause of PAL in this cohort. PAL secondary to ARDS was associated with a worse outcome. In contrast, non-ARDS PAL was successfully managed conservatively, in most cases.

A decade's experience of pediatric lung abscess and empyema at a community hospital

BACKGROUND

Discussions on the diagnostic and management of acquired pediatric lung pathology are usually published by large tertiary children's hospitals. It is likely that much of this pathology is actually seen and managed in nonacademic practices.

METHODS

A 10-year retrospective review of patients under 18-years of age, treated for lung abscesses or empyema was performed.

RESULTS

Nineteen empyema and four lung abscesses were included. Presenting symptoms, workup, and management are reviewed. A unique subset (n = 4) of atypical pulmonary pathology is described. A 14-year-old with a vaping history and a lung abscess misdiagnosed as an empyema. A 15-year-old with primary pulmonary Hodgkin's lymphoma presenting as a lung abscess and empyema. A 5-year-old with an empyema complicated by a bronchopleural fistula and a 21-year-old with autism and an acquired lung cyst.

CONCLUSION

Our dilemmas, experiences, and strategies in managing complex lung disease are generalized to community-based practice.

Endobronchial Valve Placement for Persistent Air Leaks Secondary to Pulmonary Infections

BACKGROUND

Pneumothoraces associated with infectious diseases have a higher rate of treatment failure and longer length of hospital stay than those associated with obstructive lung diseases and malignancy. Little is mentioned in the medical literature concerning the use of endobronchial 1-way valves in treating alveolar-pleural fistulae (APF) caused by pulmonary infections.

METHODS

A 7-year, single-center, retrospective analysis of patients consented for exempted off-label use of the Olympus Spiration Implantable Endobronchial Valve system to control prolonged air leaks at the University of Cincinnati Medical Center.

RESULTS

Nineteen consecutive patients had 22 separate APF events from pulmonary infections during which a total of 101 valves were placed over 23 procedures (average 4.4±2.8 valves per procedure). The average time from the first chest tube placement to valve placement was 23.4±20.8 days (range, 2 to 84 d). Chest tubes were successfully removed in 19 (86.4%) of 22 APF events without further intervention. In events not including chest tubes remaining solely for empyema treatment after cessation of air leak (n=14), the average time from valve placement to the removal of all chest tubes was 12.8±20.2 days (1 to 81 d). Thirty and ninety day all-cause mortality was 15.8%. On average, valves were removed 64.1±27.1 days (range, 38 to 135 d) after placement.

CONCLUSION

Based on our institutional experience, endobronchial valves may be a treatment option for select patients with persistent air leaks caused by pulmonary infections. Further standardized and comparative studies are required to fully understand the risks and benefits of this treatment.

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.

Complicated pneumonia in children

Complicated community-acquired pneumonia in a previously well child is a severe illness characterised by combinations of local complications (eg, parapneumonic effusion, empyema, necrotising pneumonia, and lung abscess) and systemic complications (eg, bacteraemia, metastatic infection, multiorgan failure, acute respiratory distress syndrome, disseminated intravascular coagulation, and, rarely, death). Complicated community-acquired pneumonia should be suspected in any child with pneumonia not responding to appropriate antibiotic treatment within 48-72 h. Common causative organisms are Streptococcus pneumoniae and Staphylococcus aureus. Patients have initial imaging with chest radiography and ultrasound, which can also be used to assess the lung parenchyma, to identify pleural fluid; CT scanning is not usually indicated. Complicated pneumonia is treated with a prolonged course of intravenous antibiotics, and then oral antibiotics. The initial choice of antibiotic is guided by local microbiological knowledge and by subsequent positive cultures and molecular testing, including on pleural fluid if a drainage procedure is done. Information from pleural space imaging and drainage should guide the decision on whether to administer intrapleural fibrinolytics. Most patients are treated by drainage and more extensive surgery is rarely needed; in any event, in low-income and middle-income countries, resources for extensive surgeries are scarce. The clinical course of complicated community-acquired pneumonia can be prolonged, especially when patients have necrotising pneumonia, but complete recovery is the usual outcome.

Mycoplasma pneumoniae pneumonia associated thrombosis at Beijing Children's hospital

Background

With the increase of awareness of mycoplasma pneumoniae pneumonia (MPP), we found thrombosis in severe MPP (SMPP) was not rare. The aim of the study was to investigate the clinical characteristics, treatment, and long-term prognosis of MPP-associated thrombosis.

Methods

We retrospectively reviewed the medical records of 43 children with MPP-associated thrombosis between January 2013 and June 2019 at Beijing Children’s Hospital. The results of blood coagulation studies, autoimmune antibody, thrombophilia screening, contrast-enhanced lung computed tomography, echocardiography, and blood vessel ultrasonography were analyzed, as were treatment outcomes.

Results

Forty-two patients were diagnosed with SMPP. D-dimer was higher than 5.0 mg/L in 58.1% (25/43) of patients. The mean D-dimer level was 11.1 ± 12.4 mg/L. Anticardiolipin-IgM was positive in 60.0% of patients, β2-glycoprotein-IgM in 64.0%, and lupus anticoagulant in 42.1%. Chest imaging revealed pulmonary consolidation with lobe distribution in all patients (2/3–1 lobe in 10 patients, > 1 lobe in 29 patients). In our experience, thrombosis can occur in a vessel of any part of the body, and it can be initially detected as late as 31 days after disease onset. Thrombosis in the brain and abdomen can occur early, at 5 days after disease onset. Pulmonary vessels were the most commonly involved sites in the current study, and accordingly chest pain was the most common symptom (32.6%), followed by neurological symptoms (14.0%) and abdominal pain (9.3%). Thirty-five percent of patients were asymptomatic with regard to thrombosis. All patients underwent anticoagulant therapy, and thrombus absorption took > 3 months in most patients. All patients were followed until October 2019, at which time 41 were asymptomatic and 2 had mild recurrent cough.

Conclusions

SMPP with pulmonary consolidation (> 2/3 lobe) was the most strongly associated risk factor for thrombosis. Thrombosis-associated symptoms may be subtle, even absent. Elevated D-dimer, specifically > 11.1 mg/L (even > 5.0 mg/L), would assist in the early diagnosis of thrombosis. The long-term prognosis of thrombosis was good after timely administration of anticoagulant therapy.

Giant lung cysts following necrotizing pneumonia: Resolution with conservative treatment

RATIONALE

Necrotizing pneumonia is characterized by destruction and liquefaction of the lung tissue and loss of the normal pulmonary parenchymal architecture. During the course of resolution areas of hyperlucency are formed, sometimes with the development of giant lung cysts that can be a field with fluid resembling lung abscess. There is no consensus on the management of these abnormalities.

OBJECTIVE

To assess the prevalence of giant lung cysts as a complication of necrotizing pneumonia and to report our experience with conservative treatment that achieved complete resolution.

METHODS

Medical chart reviews of all children aged 0 to 18 years hospitalized with necrotizing pneumonia in a single tertiary center from 2015 to 2017, demographic data, and clinical course during and after hospitalization as well as serial chest imaging were collected.

RESULTS

During the study period, 761 children were diagnosed with community-acquired pneumonia, 16 of 761 (2.3%) had necrotizing pneumonia and 6 of 16 (37.5%) with necrotizing pneumonia complicated by a giant lung cyst or lung abscess. All were closely observed and showed complete clinical and radiographic resolution with antibiotic treatment.

CONCLUSIONS

Treatment of giant lung cyst formation following necrotizing pneumonia by a conservative approach with prolonged antibiotics results in complete recovery with no need for invasive procedures.

Prophage Excision in Streptococcus pneumoniae Serotype 19A ST320 Promote Colonization: Insight Into Its Evolution From the Ancestral Clone Taiwan 19F-14 (ST236)

Streptococcus pneumoniae 19A ST320, a multidrug-resistant strain with high disease severity that notoriously spread before the use of expanded pneumococcal conjugate vaccines, was derived from a capsular switching event between an international strain Taiwan 19F-14 (ST236) and a serotype 19A strain. However, the molecular mechanisms underlying the adaptive evolution of 19F ST236 to 19A ST320 are unknown. In this study, we compared 19A ST320 to its ancestral clone, 19F ST236, in terms of adherence to respiratory epithelial cells, whole transcriptome, and ability to colonize a young mouse model. Serotype 19A ST320 showed five-fold higher adherence to A549 cells than serotype 19F ST236. High-throughput mRNA sequencing identified a prophage region located between dnaN and ychF in both strains; however, the genes in this region were expressed at significantly higher levels in 19A ST320 than in 19F ST236. Analysis by polymerase chain reaction (PCR) showed that the prophage is able to spontaneously excise from the chromosome and form a circular episome in 19A ST320, but not in 19F ST236. Deletion of the integrase in the prophage of 19A ST320 decreased spontaneous excision and cell adherence, which were restored by complementation. Competition experiments in mice showed that the integrase mutant was six-fold less competitive than the 19A ST320 parent (competitive index [CI]: 0.16; p = 0.02). The 19A ST320 prophage-deleted strain did not change cell adherence capacity, whereas prophage integration strains (integrase mutant and 19F) had decreased expression of the down-stream ychF gene compared to that of 19A ST320. Further deletion of ychF significantly reduced cell adherence. In conclusions, these findings suggest that spontaneous prophage induction confers a competitive advantage to virulent pneumococci.

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 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.

Invasive pneumococcal disease caused by ceftriaxone-resistant Streptococcus pneumoniae in Taiwan

BACKGROUND

Invasive pneumococcal disease (IPD) was associated with mortality, but the risk factors associated with mortality remains controversial.

METHODS

A retrospective cohort study was designed. All patients with IPD from 2011 to 2013 admitted in a medical center were screened and collected for their clinical presentations and laboratory characteristics.

RESULTS

Approximately half of the 134 IPD isolates derived from these patients belonged to three major serotypes (19A, 6A and 3), which are included in 13-valent pneumococcal conjugate vaccine (PCV13), but not in 7-valent pneumococcal conjugate vaccine (PCV7). Ceftriaxone resistance according to non-meningitis criteria was identified in 38% of the IPD isolates, and was the major independent risk factor associated with inappropriate initial therapy that subsequently contributed to mortality of the patients. Infection by serotype 6A, 15B, 19A, 19F, or 23F was the major independent risk factor associated with ceftriaxone resistance (non-meningitis criteria). 77.6% of these isolates belonged to additional PCV13 serotypes, with more than 40% expressing resistance to ceftriaxone. In terms of serotype coverage, PCV13 covered 94.1% of the IPD isolates with ceftriaxone resistance, in comparison to 21.6% only by PCV7.

CONCLUSIONS

The increase of ceftriaxone resistance in pneumococci in part driven by PCV7 vaccination in Taiwan is worrisome. The use of PCV13 in children as well as in the elderly population is likely to offer protection from the infection caused by ceftriaxone-resistant pneumococci. It is important to give an effective drug such as penicillin, fluoroquinolones or vancomycin in 2 days for improving outcome of IPD patients.

Computed tomography in children with community-acquired pneumonia

Diagnostic imaging plays a significant role in both the diagnosis and treatment of complications of pneumonia in children and chest radiography is the imaging modality of choice. Computed tomography (CT) on the other hand, is not currently a first-line imaging tool for children with suspected uncomplicated community-acquired pneumonia and is largely reserved for when complications of pneumonia are suspected or there is difficulty in differentiating pneumonia from other pathology. This review outlines the situations where CT needs to be considered in children with pneumonia, describes the imaging features of the parenchymal and pleural complications of pneumonia, discusses how CT may have a wider role in developing countries where human immunodeficiency virus (HIV) and tuberculosis are prevalent, makes note of the role of CT scanning for identifying missed foreign body aspiration and, lastly, addresses radiation concerns.

Acute otitis media caused by Streptococcus pneumoniae serotype 19A ST320 clone: epidemiological and clinical characteristics

BACKGROUND

Streptococcus pneumoniae serotype 19A ST320, a highly multiresistant and virulent clone, has emerged as a common pathogen causing acute otitis media (AOM) in children.

METHODS

Patients aged 0-18 years with AOM who presented at Mackay Memorial Hospital, Taipei, Taiwan were prospectively enrolled between December 1, 2009, and November 30, 2012. For each patient, a specimen of middle-ear fluid was obtained and cultured. S. pneumoniae isolates were tested by serotyping, antibiotic-resistance profiling, and multilocus sequence typing. Demographic characteristics and clinical history of patients with pneumococcal AOM were recorded.

RESULTS

Pneumococcal AOM was observed in 108 (24.8%) of 436 episodes. One hundred and four isolates of S. pneumoniae were available for study. The most common serotypes were 19A (67 isolates, 64.4%), followed by 19F (16 isolates, 15.4%), and 3 (7 isolates, 6.7%). Among the 85 sequence-typed isolates, Serotype 19A ST320 (50, 58.8%) was the most frequent. Children with AOM caused by Serotype 19A ST320 were younger (33.9 ± 21.4 months vs. 46.7 ± 35.9 months, p = 0.04) and had a higher rate of spontaneous rupture of the tympanic membrane (64.0% vs. 40%, p = 0.05) than those caused by isolates of other sequence types. Serotype 19A ST320 caused 90% of AOM episodes in children aged ≤ 12 months and had had higher resistance rates to penicillin according to meningeal breakpoints (p = 0.011), amoxicillin (p < 0.001) and trimethoprim/sulfamethoxazol (p < 0.001).

CONCLUSIONS

It is better to use pneumococcal conjugate vaccine effective against Serotype 19A in early infancy to prevent the first and subsequent episodes of AOM in children in Taiwan.

Necrotizing pneumonia and acute purulent pericarditis caused by Streptococcus pneumoniae serotype 19A in a healthy 4-year-old girl after one catch-up dose of 13-valent pneumococcal conjugate vaccine

Streptococcus pneumoniae is a common cause of infectious diseases in children that may lead to life-threatening complications. Acute purulent pericarditis is an uncommon complication of S. pneumoniae in the antibiotic era. A healthy 4-year-old girl was admitted with pneumonia and pleural effusion. She had received one catch-up dose of 13-valent pneumococcal conjugate vaccine at 2 years of age. She rapidly developed necrotizing pneumonia, complicated by bronchopleural fistula presenting as subcutaneous emphysema and pneumothorax and acute purulent pericarditis. S. pneumoniae serotype 19A was subsequently identified from blood, empyema and pericardial fluid cultures. After appropriate antibiotic therapy and a right lower lobectomy, her condition stabilized and she promptly recovered. This case highlights two rare potential clinical complications of pneumococcal disease in a child: necrotizing pneumonia and acute purulent pericarditis. This is the first report of a child who received just one catch-up dose of 13-valent pneumococcal conjugate vaccine at 2 years of age, as per the United States' Advisory Committee on Immunization Practice's recommendations, but who still developed severe invasive pneumococcal disease with life-threatening complications caused by S. pneumoniae serotype 19A.

The rising incidence of pediatric empyema with fistula

PURPOSE

The incidence and etiology of empyema with fistula (EWF) in children is unknown. We analyzed a national database to define the epidemiology and diagnoses associated with this condition.

METHODS

Discharge data from the Kids' Inpatient Database were reviewed for EWF (ICD-9 diagnosis code 510.0) in children ≤18 years from 2000 to 2012. Patient characteristics, institutional data, and accompanying conditions were evaluated. Weighted national estimates were calculated and incidence compared across years (2000, 2003, 2006, 2009) using the Rao-Scott Chi Square.

RESULTS

From 2000 to 2012, 908 children were hospitalized with EWF. Age distribution was bimodal. Common primary diagnoses related to the hospitalization were pneumonia/pulmonary abscess (31.2 %) and EWF (19.3 %). Manipulation of the pleural space (e.g. decortication, drainage) comprised 45.0 % of procedures. Incidence rates of EWF increased (Rao Scott Adjusted Chi Square: 16.13, p < 0.01) over the study period. Although not statistically significant, median length of stay and age of diagnosis decreased and increased, respectively.

CONCLUSION

This first, national pediatric EWF study reveals rising incidence during the years 2000-2009. Despite limitations in ICD-9 coding, concomitant primary diagnoses and procedures suggest bronchopleural fistulae likely represent the vast majority of cases in this cohort. Multi-institutional studies are needed to confirm etiology and characterize outcome of EWF.

Necrotizing Pneumonia and Its Complications in Children

Necrotizing pneumonia (NP) is an emerging complication of community acquired pneumonia (CAP) in children. This study aimed at the evaluation of etiology, clinical features, treatment, and prognosis of NP. The institutional database of children with CAP treated between April 2008 and July 2013 was searched to identify children with NP. Then, data on the NP characteristics were retrospectively reviewed and analyzed. We found that NP constituted 32/882 (3.7%) of all CAPs. The median age of children with NP was 4 (range 1-10) years. The causative pathogens were identified in 12/32 children (37.5%) with Streptococcus pneumoniae being the most common (6/32). All but one patient developed complications: parapneumonic effusion (PPE), pleural empyema or bronchopleural fistula (BPF), which required prompt local treatment. The median duration of hospital stay and antibiotic treatment was 26 (IQR 21-30) and 28 (IQR 22.5-32.5) days, respectively. Despite severe course of the disease no deaths occurred. A follow-up visit after 6 months revealed that none of the patients presented with any signs and symptoms which could be related to earlier pneumonia. Chest radiographs showed complete or almost complete resolution of pulmonary and pleural lesions in all patients. We conclude that necrotizing pneumonia is a relatively rare but severe form of CAP that is almost always complicated by PPE/empyema and/or BPF. It can be successfully treated with antibiotics and pleural drainage without major surgical intervention.

Identification of PblB mediating galactose-specific adhesion in a successful Streptococcus pneumoniae clone

The pneumococcal genome is variable and there are minimal data on the influence of the accessory genome on phenotype. Pneumococcal serotype 14 sequence type (ST) 46 had been the most prevalent clone causing pneumonia in children in Taiwan. A microarray was constructed using the genomic DNA of a clinical strain (NTUH-P15) of serotype 14 ST46. Using DNA hybridization, genomic variations in NTUH-P15 were compared to those of 3 control strains. Microarray analysis identified 7 genomic regions that had significant increases in hybridization signals in the NTUH-P15 strain compared to control strains. One of these regions encoded PblB, a phage-encoded virulence factor implicated (in Streptococcus mitis) in infective endocarditis. The isogenic pblB mutant decreased adherence to A549 human lung epithelial cell compared to wild-type NTUH-P15 strain (P = 0.01). Complementation with pblB restored the adherence. PblB is predicted to contain a galactose-binding domain-like region. Preincubation of NTUH-P15 with D-galactose resulted in decreases of adherence to A549 cell in a dose-dependent manner. Challenge of mice with NTUH-P15, isogenic pblB mutant and pblB complementation strains determined that PblB was required for bacterial persistence in the nasopharynx and lung. PblB, as an adhesin mediating the galactose-specific adhesion activity of pneumococci, promote pneumococcal clonal success.

Value of Lung Ultrasonography in the Diagnosis and Outcome Prediction of Pediatric Community-Acquired Pneumonia with Necrotizing Change

Background

Lung ultrasonography has been advocated in diagnosing pediatric community-acquired pneumonia. However, its function in identifying necrotizing pneumonia, a complication, has not been explored. This study investigated the value of lung ultrasonography in diagnosing pediatric necrotizing pneumonia and its role in predicting clinical outcomes.

Methods

We retrospectively reviewed 236 children with community-acquired pneumonia who were evaluated using lung ultrasonography within 2–3 days after admission. The ultrasonographic features assessed included lung perfusion, the presence of hypoechoic lesions, and the amount of pleural effusion. Chest computed tomography was also performed in 96 patients as clinically indicated. Detailed records of clinical information were obtained.

Results

Our results showed a high correlation between the degree of impaired perfusion in ultrasonography and the severity of necrosis in computed tomography (r = 0.704). The degree of impaired perfusion can favorably be used to predict massive necrosis in computed tomography (area under the receiver operating characteristic curve, 0.908). The characteristics of impaired perfusion and hypoechoic lesions in ultrasonography were associated with an increased risk of pneumatocele formation (odds ratio (OR), 10.11; 95% CI, 2.95–34.64) and the subsequent requirement for surgical lung resection (OR, 8.28; 95% CI, 1.86–36.93). Furthermore, a longer hospital stay would be expected if moderate-to-massive pleural effusion was observed in addition to impaired perfusion in ultrasonography (OR, 3.08; 95% CI, 1.15–8.29).

Conclusion

Lung ultrasonography is favorably correlated with chest computed tomography in the diagnosis of necrotizing pneumonia, especially regarding massive necrosis of the lung. Because it is a simple and reliable imaging tool that is valuable in predicting clinical outcomes, we suggest that ultrasonography be applied as a surrogate for computed tomography for the early detection of severe necrotizing pneumonia in children.

Etiology and epidemiology of children with acute otitis media and spontaneous otorrhea in Suzhou, China

BACKGROUND

There are scare data about bacterial etiology and the antibiotic susceptibility, serotype distribution and molecular characteristics of pneumococci in children with acute otitis media (AOM) in China.

METHODS

A prospective study was conducted in Suzhou University Affiliated Children's Hospital. All children under 18 years of age diagnosed as AOM and with spontaneous otorrhea were offered enrollment, and collection of middle ear fluid was then cultured for bacterial pathogens. The antibiotic susceptibility, serotypes, macrolide resistance genes and sequence types of Streptococcus pneumoniae strains were identified.

RESULTS

From January 2011 to December 2013, a total of 229 cases of AOM with spontaneous otorrhea were identified; of these, 159 (69.4%) middle ear fluid specimens were tested positive for bacterial pathogens. The leading cause was S. pneumoniae (47.2%), followed by Staphylococcus aureus (18.8%) and Haemophilus influenzae (7.4%). The antibiotic resistance rates of S. pneumoniae isolates to erythromycin were 99.1%, and the nonsusceptible rate to penicillin was 54.6%. The most common serotypes identified were 19A (45.1%) and 19F (35.4%). The coverage against PCV7 serotypes for this outcome was 56.1% and of PCV13 was 97.6%. The macrolide resistance was mainly mediated by both ermB and mefA/E genes (88.6%). The CC271 was the major clonal complex identified.

CONCLUSIONS

S. pneumoniae was a leading cause for AOM in children in Suzhou, China. Antibiotics resistance rates of S. pneumoniae were high and mainly due to the spread of CC271 clonal complex.

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

BACKGROUND

The incidence of necrotizing pneumococcal pneumonia has increased during the past 2 decades. We hypothesized that increased pneumococcal load or augmented inflammatory cytokine production might lead to destructive pneumococcal lung disease.

METHODS

This study enrolled prospectively 0- to 18-year-old children with a diagnosis of community-acquired pneumonia with pleural effusion admitted to 6 medical centers from March 2010 to April 2012. Children were diagnosed with pneumococcal empyema if the pleural fluid tested positive for quantitative pneumococcal (lytA) detection by real-time polymerase chain reaction. Pneumococcal empyema cases were further divided into 4 groups according to necrosis severity: (0) nonnecrosis, (1) mild necrosis, (2) cavitation and (3) bronchopleural fistula. Nasopharyngeal and pleural pneumococcal load, as well as levels of proinflammatory cytokines (TNF-α, IL-1β, IL-6, IL-8), Th1-(IL-2, IFN-γ), Th2-(IL-4, IL-10) and Th17-cytokines (IL-17), in the pleural fluid was measured.

RESULTS

Serotypes 19A and 3 accounted for 69.4% and 12.5%, respectively, of 72 cases of pneumococcal empyema. Pleural pneumococcal load was significantly higher in serotypes 19A and 3 infection than in the other strains causing infection (P = 0.006). There was a correlation between nasopharyngeal and pleural pneumococcal load (ρ = 0.35; P = 0.05). In multivariate ordinal logistic regression analysis, pleural pneumococcal load (adjusted odds ratio: 1.79; 95% confidence interval: 1.03-3.06) and IL-8 (adjusted odds ratio: 2.64; 95% confidence interval: 1.21-5.75) were independent factors associated with the severity of lung necrosis.

CONCLUSIONS

Evolution of Streptococcus pneumoniae toward increased fitness in their interaction with host and exaggerated IL-8 expression may be responsible for the increase of necrotizing pneumococcal pneumonia.

Surgical management for complications of pediatric lung injury

The etiologies of pediatric lung injury requiring surgical intervention can be infectious, traumatic, congenital, or iatrogenic. Childhood pneumonia is a significant global health problem affecting 150 million children worldwide. Sequelae of pulmonary infections potentially requiring surgery include bronchiectasis, lung abscess, pneumatocele, and empyema. Trauma, congenital conditions such as cystic fibrosis and iatrogenic injuries can result in pneumothoraces, chylothoraces, or bronchopleural fistulae. Recurrence rates for spontaneous pneumothorax treated non-operatively in pediatric patients approach 50-60%. Chylothoraces in newborns may occur spontaneously or due to birth trauma, whereas in older children the etiology is almost always iatrogenic. This article examines the surgical management for the complications of lung injury in pediatric patients. In addition, we review the available pediatric evidence for early tracheostomy as well as treatment strategies for the negative ramifications of tracheostomy.

Impact of the glpQ2 gene on virulence in a Streptococcus pneumoniae serotype 19A sequence type 320 strain

Glycerophosphodiester phosphodiesterase (GlpQ) metabolizes glycerophosphorylcholine from the lung epithelium to produce free choline, which is transformed into phosphorylcholine and presented on the surfaces of many respiratory pathogens. Two orthologs of glpQ genes are found in Streptococcus pneumoniae: glpQ, with a membrane motif, is widespread in pneumococci, whereas glpQ2, which shares high similarity with glpQ in Haemophilus influenzae and Mycoplasma pneumoniae, is present only in S. pneumoniae serotype 3, 6B, 19A, and 19F strains. Recently, serotype 19A has emerged as an epidemiological etiology associated with invasive pneumococcal diseases. Thus, we investigated the pathophysiological role of glpQ2 in a serotype 19A sequence type 320 (19AST320) strain, which was the prevalent sequence type in 19A associated with severe pneumonia and invasive pneumococcal disease in pediatric patients. Mutations in glpQ2 reduced phosphorylcholine expression and the anchorage of choline-binding proteins to the pneumococcal surface during the exponential phase, where the mutants exhibited reduced autolysis and lower natural transformation abilities than the parent strain. The deletion of glpQ2 also decreased the adherence and cytotoxicity to human lung epithelial cell lines, whereas these functions were indistinguishable from those of the wild type in complementation strains. In a murine respiratory tract infection model, glpQ2 was important for nasopharynx and lung colonization. Furthermore, infection with a glpQ2 mutant decreased the severity of pneumonia compared with the parent strain, and glpQ2 gene complementation restored the inflammation level. Therefore, glpQ2 enhances surface phosphorylcholine expression in S. pneumoniae 19AST320 during the exponential phase, which contributes to the severity of pneumonia by promoting adherence and host cell cytotoxicity.

Pneumonectomy: The final cut in a rare incidence of persistent bronchopleural fistula following empyema

The incidence of necrotizing pneumonia and empyema complicated by bronchopleural fistula is rising. We describe the case of a 2-year-old boy who presented with empyema thoracis and necrotizing pneumonia who developed a bronchopleural fistula. At initial thoracotomy for decortication, necrotic lung was found and resected. He subsequently underwent further thoracotomy, prolonged chest tube drainage and endobronchial glue application attempts to close a bronchopleural fistula. The fistula was only sealed at third thoracotomy and completion pneumonectomy. This case highlights the potential challenges faced when dealing with air leaks in the setting of infection and we discuss the treatment options available.

Expansion and evolution of Streptococcus pneumoniae serotype 19A ST320 clone as compared to its ancestral clone, Taiwan19F-14 (ST236)

BACKGROUND

The Streptococcus pneumoniae serotype 19A sequence type (ST) 320 clone, derived from an international Taiwan(19F)-14 (ST236) clone, has become prevalent in many countries.

METHODS

The dynamics of invasive pneumococcal disease (IPD) were determined using the database of the National Notifiable Disease Surveillance System in Taiwan. The virulence of 19A ST320 and Taiwan(19F)-14 (ST236) were assessed in mice. By constructing an isogenic serotype 19F variant of the 19A ST320 strain (19F ST320), we analyzed the role of capsular type and genetic background on the difference in virulence between 19A ST320 and Taiwan(19F)-14 (ST236).

RESULTS

Between 2008 and 2011, IPD due to serotype 19A increased from 2.1 to 10.2 cases per 100 000 population (P < .001); IPD due to any serotype also significantly increased (P = .01). Most serotype 19A isolates belonged to ST320. Using competition experiments in a murine model of colonization, we demonstrated that 19A ST320 outcompeted Taiwan(19F)-14 (ST236; competitive index, 20.3; P = .001). 19F ST320 was 2-fold less competitive than the 19A ST320 parent (competitive index, 0.47; P = .04) but remained 14-fold more competitive than Taiwan(19F)-14 (ST236; competitive index, 14.7; P < .001).

CONCLUSIONS

Genetic evolution of pneumococcal clones from Taiwan(19F)-14 (ST236) to 19A ST320 has made this pneumococcus better able to colonize of the nasopharynx. This evolution reflects not only a switch in capsular serotype but also changes in other loci.

Comparison of invasive pneumococcal disease caused by serotype 19A and non-19A pneumococci in children: more empyema in serotype 19A invasive pneumococcal disease

OBJECTIVE

To delineate whether serotype 19A invasive pneumococcal disease (IPD) comprised significantly more necrotizing pneumonia and empyema in children, we compared the clinical characteristics between serotype 19A and non-19A IPD.

METHODS

Between January 2007 and December 2011, cases of children with IPD who were treated at the National Taiwan University Hospital were reviewed. Patients were assigned to the 19A group or the non-19A group based on the serotype. Their demographic data, clinical course, laboratory results, diagnosis, complications, and sequelae were collected and analyzed.

RESULTS

Overall, 27 patients were included in the 19A group and 29 patients in the non-19A group. Compared with non-19A group, serotype 19A tended to cause IPD in patients without major underlying diseases (p = 0.015). Bacteremia without pneumonia or meningitis was found more frequently in the non-19A group (45% vs. 11%, p = 0.01), and pneumonia with or without empyema occurred significantly more frequently in the 19A group (89% vs. 52%, p = 0.006). Patients in the19A group had longer duration of fever (12 vs. 3 days, p = 0.01), and required more intensive care (78% vs. 41%, p = 0.01) and more video-assisted thoracoscopic surgery (74% vs. 28%, p = 0.001).

CONCLUSION

In comparison with the other serotypes, serotype 19A IPD has significantly more empyema which required more video-assisted thoracoscopic surgery and more intensive care.