Molecular analysis improves pathogen identification and epidemiologic study of pediatric parapneumonic empyema

Parapneumonic Empyema Complicating Community-acquired Pneumonia: Etiology in the Era of Pneumococcal Vaccination and Role of Molecular Diagnosis

BACKGROUND

Impact of pneumococcal conjugate vaccines (PCVs) on pneumococcal disease is well described; pneumococcus is infrequently identified by culture in pneumonia. Yield is higher when pleural fluid is cultured. Polymerase chain reaction (PCR) in pleural fluid samples improves pathogen identification, particularly in the case of S. pneumoniae.

METHODS

Healthy children with empyema who underwent pleural fluid drainage were eligible. Demographics and PCV immunization status were collected. Blood/pleural fluid cultures were obtained. Pleural fluid samples were sent for PCR for pathogen. Serotyping was done by Neufeld-Quellung reaction on pneumococcus isolates, and PCR in culture negative cases.

RESULTS

From December 2018 to September 2023, 74 patients were enrolled. Pathogens were cultured in 22 patients (29.7%), with pneumococcus found in 6 (27.3%). PCR identified additional pathogens in 23 patients (31.1%), including 18 pneumococci (81.8%) and real-time PCR identified 5 more pneumococci, totaling 29 pneumococci, with 23 (79.3%) detected by PCR only. Serotype information was available for 27 (93.1%) pneumococci; 22 (81.5%) were identified as PCV-13 serotypes, with serotype 3 being present in 17 (63%) cases. Among patients with a PCV-13 serotype detected through culture or molecular methods, 15 (68.2%) were fully vaccinated with PCV-13, including 11 of 17 (65%) with serotype 3.

CONCLUSION

S. pneumoniae, particularly serotype 3, is the leading bacterial pathogen in children ≤18 years old. Molecular diagnosis enhances pathogen detection. Ongoing surveillance is crucial to monitor etiology changes as new pneumococcal vaccines are introduced.

Use of Polymerase Chain Reaction to Characterize the Etiology of Culture-Negative Empyema and Parapneumonic Effusion Among Alaska Native Children-2018-2023

We used polymerase chain reaction (PCR) to identify bacterial infections in culture-negative pleural fluid specimens from Alaska Native children hospitalized with empyema. PCR identified ≥1 organism in 11 (79%) of 14 specimens. Streptococcus pneumoniae serotype 3 was detected in 6 specimens; all 6 participants had received 13-valent pneumococcal conjugate vaccine.

Clinical Impact of Pleural Fluid Streptococcus pneumoniae Polymerase Chain Reaction Testing in Children With Complicated Pneumonia

BACKGROUND

While Streptococcus pneumoniae (Spn) is the leading cause of pediatric complicated community-acquired pneumonia (cCAP), it is infrequently recovered by culture-based methods. We studied the real-world clinical impact of an Spn polymerase chain reaction (PCR) assay for pleural fluid.

METHODS

This pre-post quasi-experimental cohort study compared pathogen detection, antibiotic usage, and outcomes in children hospitalized with cCAP requiring pleural effusion or empyema drainage at Children's Hospital Colorado between 2016 and 2023. Patients were compared across 2 diagnostic periods: pre-Spn PCR and post-Spn PCR. Cox proportional hazard models compared time from admission to pathogen detection, optimal therapy (narrowest pathogen-directed or guideline-recommended empiric therapy), and methicillin-resistant Staphylococcus aureus (MRSA) therapy discontinuation between periods.

RESULTS

Compared to the pre-Spn PCR cohort (n = 149), the post-Spn PCR cohort (n = 79) was more likely to have a pathogen detected (73.4% post-PCR vs 38.9% pre-PCR, P < .001), driven by more Spn detections (45.6% vs 14.1%, P < .001). Time to pathogen detection during hospitalization was shorter in the post-Spn PCR period (P < .001). The post-PCR cohort was more likely to receive optimal therapy (84.8% vs 53.0%, P < .001), with shorter median times to optimal antibiotics (4.9 vs 10.0 days, P < .001) and MRSA therapy discontinuation (1.5 vs 2.5 days, P = .03). There were no differences in hospital length of stay or readmissions.

CONCLUSIONS

Spn molecular testing of pleural fluid in children with cCAP resulted in significantly more microbiologic diagnoses and was associated with the optimization of antibiotics and decreased exposure to MRSA therapy, suggesting its clinical impact for pediatric complicated pneumonia.

Empiric Antibiotic Therapy in 1402 Children With Parapneumonic Effusion/Pleural Empyema in Germany: A Long-term Surveillance Study

OBJECTIVE

This study investigated empiric antibiotic treatment (EAT), guideline adherence, antibiotic streamlining and clinical outcomes in 1402 hospitalized children with pediatric parapneumonic effusion/pleural empyema (PPE/PE).

METHODS

A nationwide surveillance study collected data on EAT, clinical course/outcome, pathogens, susceptibility testing and antibiotic streamlining of children with PPE/PE in Germany between 2010 and 2018. Subgroups were compared using χ2 test/Fisher exact test, Mann-Whitney U test and linear regression analysis adjusting for patient age where appropriate.

RESULTS

Complete data on EAT were available for 1402 children. In children with monotherapy (n = 567) and in children with combination therapy of 2 antibiotics (n = 589), the most commonly used antibiotics were aminopenicillin/beta-lactamase inhibitor [138/567 (24.3%) and 102/589 (17.3%)] and cefuroxime [291/567 (51.3%) and 294/589 (49.9%)]. The most common combinations with these beta-lactams were macrolides, aminoglycosides and clindamycin. We observed no difference in clinical severity/outcome between EAT with aminopenicillin/beta-lactamase inhibitor and cefuroxime, neither when used in monotherapy nor when used in combination therapy of 2 antibiotics. Species diagnosis of Streptococcus pneumoniae (n = 192), Streptococcus pyogenes (n = 111) or Staphylococcus aureus (n = 38) in polymerase chain reaction or culture from pleural fluid or blood resulted in a switch to an appropriate narrow-spectrum beta-lactam therapy in 9.4%, 18.9 % and 5.2% of children. In a subset of children with reported bacterial susceptibility testing, penicillin resistance was reported in 3/63 (4.8%) of S. pneumoniae and methicillin resistance in S. aureus was reported in 10/32 (31.3%) of children.

CONCLUSION

This study points to antibiotic overtreatment in children with PPE/PE, particularly the frequent use of combinations of antibiotics. Children receiving combinations of antibiotics did not show differences in clinical outcomes. The low rate of children with streamlined antibiotic therapy even upon pathogen detection indicates a necessity for antibiotic stewardship measures in PPE/PE and the need of investigating other potential therapeutic strategies as anti-inflammatory therapy.

Rapid detection of S. pyogenes and S. pneumoniae in pleural fluid for diagnosis of parapneumonic empyema

The aim of this study was to assess the reliability of rapid antigen detection tests (RADT) for Streptococcus pyogenes (GAS) and Streptococcus pneumoniae on pleural fluid samples for diagnosis of parapneumonic effusion/empyema (PPE) and their potential for improving pathogen identification rates. Sixty-three pleural samples were included from 54 patients on which GAS and S. pneumoniae RADT (BinaxNOW), culture, 16S rRNA PCR, and S. pneumoniae-specific PCR were performed. GAS RADT showed a sensitivity of 95.2% and a specificity of 100%. Pneumococcal RADT showed a sensitivity of 100% and specificity of 88.6%. Both RADT increased the pathogen identification rate in PPE compared to culture.

Children hospitalized with community-acquired pneumonia complicated by effusion: a single-centre retrospective cohort study

OBJECTIVES

To describe children hospitalized with community-acquired pneumonia complicated by effusion (cCAP).

DESIGN

Retrospective cohort study.

SETTING

A Canadian children's hospital.

PARTICIPANTS

Children without significant medical comorbidities aged < 18 years admitted from January 2015-December 2019 to either the Paediatric Medicine or Paediatric General Surgery services with any pneumonia discharge code who were documented to have an effusion/empyaema using ultrasound.

OUTCOME MEASURES

Length of stay; admission to the paediatric intensive care unit; microbiologic diagnosis; antibiotic use.

RESULTS

There were 109 children without significant medical comorbidities hospitalized for confirmed cCAP during the study period. Their median length of stay was 9 days (Q1-Q3 6-11 days) and 35/109 (32%) were admitted to the paediatric intensive care unit. Most (89/109, 74%) underwent procedural drainage. Length of stay was not associated with effusion size but was associated with time to drainage (0.60 days longer stay per day delay in drainage, 95%CI 0.19-1.0 days). Microbiologic diagnosis was more often made via molecular testing of pleural fluids (43/59, 73%) than via blood culture (12/109, 11%); the main aetiologic pathogens were S. pneumoniae (40/109, 37%), S. pyogenes (15/109, 14%), and S. aureus (7/109, 6%). Discharge on a narrow spectrum antibiotic (i.e. amoxicillin) was much more common when the cCAP pathogen was identified as compared to when it was not (68% vs. 24%, p < 0.001).

CONCLUSIONS

Children with cCAP were commonly hospitalized for prolonged periods. Prompt procedural drainage was associated with shorter hospital stays. Pleural fluid testing often facilitated microbiologic diagnosis, which itself was associated with more appropriate antibiotic therapy.

Modern approaches at the management of children with community-acquired pneumonia

Experts of The Union of Pediatricians of Russia have developed current clinical guidelines for management of children with community-acquired pneumonia, which were approved by the Scientific and Practice Council of Ministry of Public Health of the Russian Federation in January 2022. Particular attention is paid to the etiological structure, modern classification, diagnostic tests and flagship approaches to antibacterial therapy of community-acquired pneumonia in children based on the principles of evidentiary medicine. 

Incipient empyema as an embolic complication of group A streptococcal septic arthritis in a patient with concomitant influenza B infection

A 43-year-old healthy male presented with left ankle septic arthritis. Surgical specimens cultured Streptococcus pyogenes (group A Streptococcus, GAS) and IV benzylpenicillin was commenced. In the setting of coryzal symptoms, a chest radiograph and nasopharyngeal swab revealed a left-sided pleural effusion and influenza B infection, respectively. Persisting fevers, rising CRP, and increasing breathlessness led to repeat chest radiography showing a rapidly enlarging left-sided effusion. Following intercostal catheter insertion with intrapleural fibrinolytic therapy, 6 L of haemorrhagic fluid was drained leading to defervescence and clinical improvement. At follow-up 4 weeks later, he was asymptomatic with a normal chest radiograph. Similar to previous reported cases of GAS empyema, this case was associated with concurrent viral respiratory tract infection, but is unusual as it arose through haematogenous seeding from an extra-thoracic source. This case reminds clinicians to be aware of the strongly pyogenic nature of GAS and its significance as a potential cause of pleural infection, especially in patients with concomitant viral respiratory infections.

Molecular diagnostic of complicated pneumonia in the post-vaccine era

BACKGROUND

The etiological diagnosis of community-acquired pneumonia (CAP) is still a challenge. We compared the conventional culture method and real-time polymerase chain reaction (RT-PCR) for the identification of Streptococcus pneumoniae in severe pediatric CAP.

METHODS

A retrospective hospital-based study was conducted. From 2012 to 2018, we have selected patients who had peripheral blood and/or pleural fluid collected for etiological investigation by RT-PCR.

RESULTS

We included 113 children (median age: 3 years; interquartile range 1-6 years). RT-PCR increased the detection rate of S. pneumoniae by 6.5 times using blood samples and eight times using pleural fluid samples. Patients subjected to RT-PCR showed more prolonged hospitalization (p = 0.006), fewer comorbidities (p = 0.03), presence of pleural effusion (p = 0.001), presence of young forms of leukocytes (p = 0.001) and radiograph with characteristics of pneumonia (p = 0.002). The presence of pleural effusion [odds ratio (OR) = 14.7, 95% confidence interval (CI) 1.6-133.9; p = 0.01] and young forms of leukocytes (OR = 8.9, 95% CI 0.9-84.4; p = 0.05) were risk factors for positive RT-PCR pneumococcal when multivariate analysis was performed.

CONCLUSIONS

RT-PCR is a reliable method for diagnosing severe CAP using sterile materials and a potentially applicable method in patients with clinical, radiological and non-specific laboratory characteristics of lower respiratory tract infection, especially in complicated cases with pleural effusion.

Clinical relevance of molecular testing methods in the diagnosis and guidance of therapy in patients with staphylococcal empyema: a systematic review and meta-analysis

Background

Efficient detection tools for determining staphylococcal pleural infection are critical for its eradication. The objective of this meta-analysis was to assess the diagnostic utility of nucleic acid amplification tests (NAAT) in suspected empyema cases to identify staphylococcal strains and avoid unnecessary empiric methicillin-resistant Staphylococcus aureus (MRSA) therapy.

Methods

From inception to July 24, 2021, relevant records were retrieved from PubMed, Embase, Scopus, Web of Science, and the Cochrane Library. The quality of studies was determined using the QUADAS-2 tool. The pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and hierarchical summary receiver operating characteristic (HSROC) curve for NAAT's diagnostic performance were evaluated using an HSROC model.

Results

Eight studies comprising 424 samples evaluated NAAT accuracy for Staphylococcus aureus (SA) identification, while four studies comprising 317 samples evaluated methicillin-resistant Staphylococcus aureus (MRSA) identification. The pooled NAAT summary estimates for detection of both SA (sensitivity: 0.35 (95% CI 0.19-0.55), specificity: 0.95 (95% CI 0.92-0.97), PLR: 7.92 (95% CI 4.98-12.59), NLR: 0.44 (95% CI 0.14-1.46), and DOR: 24.0 (95% CI 6.59-87.61) ) and MRSA (sensitivity: 0.45 (95% CI 0.15-0.78), specificity: 0.93 (95% CI 0.89-0.95), PLR: 10.06 (95% CI 1.49-67.69), NLR: 0.69 (95% CI 0.41-1.15), and DOR: 27.18 (95% CI 2.97-248.6) ) were comparable. The I2 statistical scores for MRSA and SA identification sensitivity were 13.7% and 74.9%, respectively, indicating mild to substantial heterogeneity. PCR was frequently used among NAA tests, and its diagnostic accuracy coincided well with the overall summary estimates. A meta-regression and subgroup analysis of country, setting, study design, patient selection, and sample condition could not explain the heterogeneity (meta-regression P = 0.66, P = 0.46, P = 0.98, P = 0.68, and P = 0.79, respectively) in diagnostic effectiveness.

Conclusions

Our study suggested that the diagnostic accuracy of NAA tests is currently inadequate to substitute culture as a principal screening test. NAAT could be used in conjunction with microbiological culture due to the advantage of faster results and in situations where culture tests are not doable.

A challenging case of thoracic empyema caused by Prevotella spp

We report here the case of a 49-year-old man admitted for a diagnostic work-up of bilateral lung nodules. Empyema rapidly developed after a chest computed-tomodensitometry guided lung puncture. Despite the lack of obvious aetiology after two biopsies, the diagnosis was reached by performing 16S ribosomal DNA (rDNA) sequence analysis, which identified Prevotella spp in the pleural liquid. The empyema and lung nodules resolved after appropriate antibiotic therapy.

Pediatric Parapneumonic Effusion/Pleural Empyema in Japan: A Nationwide Survey

BACKGROUND

Pediatric parapneumonic effusion/ pleural empyema (PPE/PE) is a severe infectious condition, and its management should be guided by local epidemiology and the patient's medical history. This survey aimed to determine the clinical and bacteriologic features of PPE/PE in Japan.

METHODS

A nationwide retrospective questionnaire survey was conducted, targeting 159 pediatric specialist training medical facilities for inpatients ≤18 years of age who were admitted for PPE/PE between January 2007 and December 2016.

RESULTS

Valid responses were obtained from 122 facilities, and 96 patients were identified from 38 facilities. The median age (interquartile range) was 2.7 (0.8-7.8) years. Overall, 60 (63 %) patients were men and 49 (51%) had comorbidities. The causative bacteria were identified in 59% of patients by culture except in one case identified using PCR. Streptococcus pyogenes (16%), Staphylococcus aureus (14%) and Streptococcus pneumoniae (13%) were the major pathogens. Carbapenems were administered to 34% of patients without comorbidities. Chest tube drainage was performed in 71%, intrapleural fibrinolytic therapy in 9.4%, surgery in 25% and mechanical ventilation in 29% of the patients. Five patients (5.2%) had complications and one (1.1%) had sequelae, but all patients (100%) survived.

CONCLUSIONS

This is first report of a nationwide survey pertaining to pediatric PPE/PE in Japan. We found that the etiology showed a different trend from that reported in other countries. It is worrisome that molecular methods were rarely used for pathogenic diagnosis and carbapenems were overused. Thus, it is imperative to establish clinical guidelines for PPE/PE in Japan.

Keep the old, in with the new: The changing face of pleural effusions

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Pneumococcal Serotype Identification by Capsular Sequence Typing (CST): A Modified Novel Approach for Serotyping Directly in Clinical Samples

As almost 60-70% of Invasive Pneumococcal Disease (IPD) is identified by nonculture methods in Greece, serotyping is of high importance for the better monitoring of pneumococcal serotypes due to the availability of conjugate vaccines. The aim of the study was the modification and direct application of the Capsular Sequence Typing (CST) assay in clinical samples in order to serotype Streptococcus pneumoniae culture-negative, Polymerase Chain Reaction (PCR_-positive samples, followed by CST group specific single-tube PCR assays. A two-step PCR modified assay was applied on a total of 306 samples (such as CSF, blood, pleural and middle ear fluids, isolates) obtained from 283 patients with IPD. The overall performance permits a rapid, accurate and cost-effective method for nonculture pneumococcal serotyping. As the management of IPD is closely related to the continuous monitoring of pneumococcal serotypes, the proposed approach proved to be a valuable tool for the typing and epidemiological monitoring of S. pneumoniae, for the evaluation of the overall impact of vaccination programs in the era of pneumococcal conjugate vaccines, in order to initiate the appropriate vaccination strategy.

Rapid identification of pathogens associated with ventilator-associated pneumonia by Nanopore sequencing

BACKGROUND

Aetiology detection is crucial in the diagnosis and treatment of ventilator-associated pneumonia (VAP). However, the detection method needs improvement. In this study, we used Nanopore sequencing to build a quick detection protocol and compared the efficiency of different methods for detecting 7 VAP pathogens.

METHODS

The endotracheal aspirate (ETA) of 83 patients with suspected VAP from Peking University Third Hospital (PUTH) was collected, saponins were used to deplete host genomes, and PCR- or non-PCR-amplified library construction methods were used and compared. Sequence was performed with MinION equipment and local data analysis methods were used for sequencing and data analysis.

RESULTS

Saponin depletion effectively removed 11 of 12 human genomes, while most pathogenic bacterial genome results showed no significant difference except for S. pneumoniae. Moreover, the average sequence time decreased from 19.6 h to 3.62 h. The non-PCR amplification method and PCR amplification method for library build has a similar average sensitivity (85.8% vs. 86.35%), but the non-PCR amplification method has a better average specificity (100% VS 91.15%), and required less time. The whole method takes 5-6 h from ETA extraction to pathogen classification. After analysing the 7 pathogens enrolled in our study, the average sensitivity of metagenomic sequencing was approximately 2.4 times higher than that of clinical culture (89.15% vs. 37.77%), and the average specificity was 98.8%.

CONCLUSIONS

Using saponins to remove the human genome and a non-PCR amplification method to build libraries can be used for the identification of pathogens in the ETA of VAP patients within 6 h by MinION, which provides a new approach for the rapid identification of pathogens in clinical departments.

Parainfluenza Virus Types 1-3 Infections Among Children and Adults Hospitalized With Community-acquired Pneumonia

BACKGROUND

Parainfluenza virus (PIV) is a leading cause of lower respiratory tract infections. Although there are several distinct PIV serotypes, few studies have compared the clinical characteristics and severity of infection among the individual PIV serotypes and between PIV and other pathogens in patients with community-acquired pneumonia.

METHODS

We conducted active population-based surveillance for radiographically confirmed community-acquired pneumonia hospitalizations among children and adults in 8 US hospitals with systematic collection of clinical data and respiratory, blood, and serological specimens for pathogen detection. We compared clinical features of PIV-associated pneumonia among individual serotypes 1, 2, and 3 and among all PIV infections with other viral, atypical, and bacterial pneumonias. We also compared in-hospital disease severity among groups employing an ordinal scale (mild, moderate, severe) using multivariable proportional odds regression.

RESULTS

PIV was more commonly detected in children (155/2354; 6.6%) than in adults (66/2297; 2.9%) (P < .001). Other pathogens were commonly co-detected among PIV cases (110/221; 50%). Clinical features of PIV-1, PIV-2, and PIV-3 infections were similar to one another in both children and adults with pneumonia. In multivariable analysis, children with PIV-associated pneumonia exhibited similar severity to children with other nonbacterial pneumonia, whereas children with bacterial pneumonia exhibited increased severity (odds ratio, 8.42; 95% confidence interval, 1.88-37.80). In adults, PIV-associated pneumonia exhibited similar severity to other pneumonia pathogens.

CONCLUSIONS

Clinical features did not distinguish among infection with individual PIV serotypes in patients hospitalized with community-acquired pneumonia. However, in children, PIV pneumonia was less severe than bacterial pneumonia.

Comparison of pediatric empyema secondary to tuberculosis or non-tuberculosis community-acquired pneumonia in those who underwent surgery in high TB burden areas

INTRODUCTION

Tuberculous empyema (TE) in children is common in high-TB burden and medical resource-limited areas. However, studies that evaluate the characteristics of TE in children are sparse. This study aimed to analyze the clinical features of pediatric TE receiving surgical intervention.

METHODS

We performed a retrospective study of children with empyema secondary to community-acquired pneumonia who underwent surgery in our institution. The clinical characteristics were compared between TE and empyema secondary non-tuberculosis infection (non-tuberculosis empyema, NTE).

RESULTS

One hundred patients were included (27 with TE and 73 with NTE). Stage 3 empyema occupied 81.5% and 45.2% of TE and NTE in this study. The TE children had older age, longer duration of illness, and milder symptoms. Pleural fluid culture was positive for Mycobacterium tuberculosis in 7.4% of patients with TE. Lymph node enlargement, lymph node calcification, and pleural nodules presented in TE with high specificity (93.2%, 98.6%, and 98.5%) but low sensitivity (33.3%, 14.8%, and 29.6%) on CT scan. Thoracoscopy surgery was performed in 14 (51.9%) in TE and 39 (53.4%) in NTE. Postoperative chest-tube indwelling time was longer (7.85 ± 5.00 vs. 4.89 ± 1.81 days, p < .001), and more patients had incomplete lung expansion after 3 months in TE.

CONCLUSION

Tuberculosis infection should be screened in management of children with empyema in high-TB burden areas. Pediatric TE usually presented at older age and with milder respiratory symptoms. Pleural biopsy during surgery is often necessary to confirm the cause of infection. Thoracotomy is still required in some pediatric TE or NTE with delayed treatment in medical resource-limited area.

Streptococcal pneumonia-associated hemolytic uremic syndrome treated by T-antibody-negative plasma exchange in children: Two case reports

BACKGROUND

The occurrence of Streptococcus pneumoniae-associated hemolytic uremic syndrome (SP-HUS) is increasing. Thomsen-Friedenreich antigen activation is highly involved in the pathogenesis of SP-HUS, and T-antibody-negative plasma exchange (PE) may be effective in the treatment of severe cases of SP-HUS.

CASE SUMMARY

We retrospectively reviewed two pediatric patients with SP-HUS. Both clinical features and laboratory examination results of the children were described. T-antibody-negative PE was performed in both cases. Both children made a full recovery after repeated PE and remained well at a 2 year follow-up.

CONCLUSION

Streptococcal pneumonia continues to be an uncommon but important cause of HUS. The successful treatment of the presented cases suggests that T-antibody-negative PE may benefit patients with SP-HUS.

Effect of Prehospital Antibiotic Therapy on Clinical Outcome and Pathogen Detection in Children With Parapneumonic Pleural Effusion/Pleural Empyema

BACKGROUND

Parapneumonic pleural effusion and pleural empyema (PPE/PE) are complications of community-acquired pneumonia. The objective of this study was to analyze prehospital antibiotic therapy (PH-ABT) of children with PPE/PE and investigate its effects on clinical outcome and pathogen detection.

METHODS

Prospective nationwide active surveillance in Germany between October 2010 and June 2018. Children and adolescents <18 years of age with pneumonia-associated PE or PPE requiring drainage or with persistence of PPE/PE >7 days were included.

RESULTS

A total of 1724 children with PPE/PE were reported, of whom 556 children (32.3% of 1719 with available data) received PH-ABT. Children with PH-ABT had a shorter median hospital length of stay (15 vs. 18 days, P < 0.001), a longer time from onset of symptoms until hospital discharge (25 vs. 23 days, P = 0.002), a lower rate of intensive care unit admission (58.3% vs. 64.4%, P = 0.015) and fewer infectious complications (5.9% vs. 10.0%; P = 0.005). Bacterial pathogens in blood or pleural fluid culture were detected in 597 (34.5%) of 1513 children. Positive culture results were less frequent in children with than without PH-ABT (81/466 [17.4%] vs. 299/1005 [29.8%]; P < 0.001), whereas detection rates in pleural fluid samples by polymerase chain reaction were similar (91/181 [50.3%] vs. 220/398 [55.3%]; P = 0.263).

CONCLUSIONS

In children with PPE/PE, PH-ABT significantly reduced the overall rate of bacterial pathogen detection by culture, but not by polymerase chain reaction. PH-ABT was associated with a lower rate of infectious complications but did not affect the overall duration of disease. We therefore speculate that the duration of PPE/PE is mainly a consequence of an infection-induced inflammatory process, which can only partially be influenced by antibiotic treatment.

Identification of Microbiome Etiology Associated With Drug Resistance in Pleural Empyema

Identification of the offending organism and appropriate antimicrobial therapy are crucial for treating empyema. Diagnosis of empyema is largely obscured by the conventional bacterial cultivation and PCR process that has relatively low sensitivity, leading to limited understanding of the etiopathogenesis, microbiology, and role of antibiotics in the pleural cavity. To expand our understanding of its pathophysiology, we have carried out a metagenomic snapshot of the pleural effusion from 45 empyema patients by Illumina sequencing platform to assess its taxonomic, and antibiotic resistome structure. Our results showed that the variation of microbiota in the pleural effusion is generally stratified, not continuous. There are two distinct microbiome clusters observed in the forty-five samples: HA-SA type and LA-SA type. The categorization is mostly driven by species composition: HA-SA type is marked by Staphylococcus aureus as the core species, with other enriched 6 bacteria and 3 fungi, forming a low diversity and highly stable microbial community; whereas the LA-SA type has a more diverse microbial community with a distinct set of bacterial species that are assumed to be the oral origin. The microbial community does not shape the dominant antibiotic resistance classes which were common in the two types, while the increase of microbial diversity was correlated with the increase in antibiotic resistance genes. The existence of well-balanced microbial symbiotic states might respond differently to pathogen colonization and drug intake. This study provides a deeper understanding of the pathobiology of pleural empyema and suggests that potential resistance genes may hinder the antimicrobial therapy of empyema.

Outcome of Severe Bacterial Pneumonia in the Era of Pneumococcal Vaccination

Introduction: After the introduction of pneumococcal conjugate vaccines, community-acquired pneumonia (CAP) caused by Streptococcus pneumoniae has decreased whereas Staphylococcus aureus and Streptococcus pyogenes could be increasing. These bacteria have been associated with high rates of complications. Aims: (1) To describe the characteristics of pediatric bacterial CAP requiring hospitalization. (2) To compare outcomes according to causative microorganisms. (3) To analyze changes in bacterial CAP rate and etiology over time. Patients and Methods: Retrospective single-center study of inpatients aged 1 month-16 years with culture-confirmed bacterial CAP in 2010-2018 in Madrid, Spain. Results: We included 64 cases (42 S. pneumoniae, 13 S. pyogenes and 9 S. aureus). Culture-confirmed CAP represented 1.48-2.33/1,000 all-cause pediatric hospital admissions, and its rate did not vary over time. However, there was a significant decrease in pneumococcal CAP in the last 3 years of the study (78% of CAP in 2010-2015 vs. 48% in 2016-18, p = 0.017). Median hospital stay was 10.5 days (interquartile range 5-19.5), 38 patients (59%) developed complications and 28 (44%) were admitted to the intensive care unit. Outcomes were similar among children with S. pneumoniae and S. aureus CAP, whereas S. pyogenes was associated with a higher risk for complications (OR 8 [95%CI 1.1-57.2]) and ICU admission (OR 7.1 [95%CI 1.7-29.1]) compared with pneumococcal CAP. Conclusion: In a setting with high PCV coverage, culture-confirmed bacterial CAP did not decrease over time and there was a relative increase of S. pyogenes and S. aureus. Children with CAP caused by S. pyogenes were more likely to develop complications.

Expanded sequential quadriplex real-time polymerase chain reaction (PCR) for identifying pneumococcal serotypes, penicillin susceptibility, and resistance markers

We expanded our current Centers for Disease Control and Prevention triplexed real-time polymerase chain reaction scheme identifying 11 individual serotypes and 10 serogroups to a quadriplex format identifying 34 individual serotypes and 13 small serogroups, 4 antibiotic resistance determinants, pilus targets, and penicillin susceptibility. Newly developed assays are specific for serotypes/serogroups, are sensitive (10 copies/reaction), and further discriminate larger serogroups into individual serotypes or smaller serogroups.

Multiplex bacterial polymerase chain reaction in a cohort of patients with pleural effusion

Background

The identification of the pathogens in pleural effusion has mainly relied on conventional bacterial culture or single species polymerase chain reaction (PCR), both with relatively low sensitivity. We investigated the efficacy of a commercially available multiplex bacterial PCR assay developed for pneumonia to identify the pathogens involved in pleural infection, particularly empyema.

Methods

A prospective, monocentric, observational study including 194 patients with pleural effusion. Patients were evaluated based on imaging, laboratory values, pleura ultrasound and results of thoracentesis including conventional microbiology studies during hospitalisation. Multiplex bacterial PCR (Curetis Unyvero p55) was performed in batch and had no influence on therapeutic decisions.

Results

Overall, there were 51/197 cases with transudate and 146/197 with exudate. In 42% (n = 90/214) there was a clinical suspicion of parapneumonic effusion and the final clinical diagnosis of empyema was made in 29% (n = 61/214) of all cases. The most common microorganisms identified in the cases diagnosed with empyema were anaerobes [31] followed by gram-positive cocci [10] and gram-negative rods [4]. The multiplex PCR assay identified more of the pathogens on the panel than the conventional methods (23.3% (7/30) vs. 6.7% (2/30), p = 0.008).

Conclusion

The multiplex PCR-based assay had a higher sensitivity and specificity than conventional microbiology when only the pathogens on the pneumonia panel were taken into account. A dedicated pleural empyema multiplex PCR panel including anaerobes would be needed to cover most common pathogens involved in pleural infection.

Identifying pneumococci in parapneumonic pleural effusion: Is there a role for culture-independent methods?

OBJECTIVE

To evaluate culture-independent procedures (immunochromatography and quantitative polymerase chain reaction [qPCR]) in the detection and susceptibility of Streptococcus pneumoniae directly from culture-negative pleural fluid (PF) in children.

METHOD

Detection of S. pneumoniae in PF of children with parapneumonic effusion and/or empyema by using two culture-independent methods: an immunochromatographic membrane test (IMT) which identifies the pneumococcal C antigen, and a real-time PCR test to detect pneumococcal genes lytA and pbp2b, a marker of susceptibility of β-lactam agents, in PF samples.

RESULTS

We tested 36 PF specimens and recorded the previous use of antimicrobials. In the final analysis, 34 samples were included. IMT and qPCR presented positive results in 23 (67.6%) and 24 (70.6%) of the samples, respectively, showing a moderate agreement (k = 0.518) between the two methods. From the 36 children included, 34 (94.4%) had antibiotic data available by the time when PFs were collected. Thirty-four (100%) children had been given treatment before PF sampling, with 33 (97%) receiving β-lactam antibiotics administered empirically. Of the 24 lytA real-time positive samples, 21 (87.5%) were also positive for pbp2b, a marker of β-lactam susceptibility.

CONCLUSION

The reduced sensitivity of culture for pneumococcal detection can be improved through the addition of IMT and qPCR analysis. The utility of qPCR combining detection of lytA and a marker of β-lactam susceptibility should be explored further.

Oral Antibiotics for Treating Children With Community-Acquired Pneumonia Complicated by Empyema

No consensus exists on management of children with community-acquired pneumonia complicated by empyema (CAP-Em). We evaluated outpatient oral (O-Abx) compared with parenteral antibiotics (OPAT) in children with CAP-Em. We also evaluated inflammatory markers to guide length of treatment. We conducted a retrospective cohort study of patients discharged (2006-2016) with CAP-Em. Primary outcome measured was treatment success (no change in antibiotics or readmission to hospital for treatment of CAP-Em). White blood cell (WBC) count, C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR) serial measurements were identified. Success was achieved in 133/144 (92.4%) O-Abx and 7/12 (58%) OPAT patients (P = .0031). WBC and CRP decreased early; and ESR increased initially (admit and switch to O-Abx) and decreased by end of treatment. O-Abx is the modality of choice for treatment of CAP-Em after hospital discharge. WBC and CRP are useful to monitor success of O-Abx switch; and ESR provides guidance for length of treatment.

12 years active surveillance for pediatric pleural empyema in a Mexican hospital: effectiveness of pneumococcal 13-valent conjugate vaccine, and early emergence of methicillin-resistant Staphylococcus aureus

Background:

Previous publications have proved the effectiveness of the 13-valent pneumococcal conjugate vaccine (PCV13) on pneumococcal pleural empyema (PnPE) in children, with little emergence of other pathogens. We searched the literature to establish whether PCV13 reduces PnPE, and to identify other pathogens causing pleural empyemas (PEs).

Material and methods:

From October 2005 to January 2018 (12.3 years) we performed active surveillance for all cases of PE at the General Hospital of Tijuana, Mexico. Isolates from pleural fluid (PF) were identified by conventional culture, and since 2014, polymerase chain reaction (PCR) was added for all culture-negative PFs. Streptococcus pneumoniae serotypes were detected by either Quellung reaction (Statens Serum Institute®) or PCR. Clinical, imagenological, laboratorial and microbiological evaluation was performed on each patient. Statistical analysis was purely descriptive.

Results:

A total of 64 PEs were identified (5.28/year). Median age was 51 months (1–191), hospitalization days 18 (4–35). Decortication was performed in 42%, and two children died (3.2%). Bacterial identification was obtained from 51 (80%). S. pneumoniae was the leading cause (29 = 56.8%), followed by Staphylococcus aureus (14 = 27.4%), Streptococcus pyogenes (3–5 = 9%) and others (5 = 9.8%). PCV13 was initiated in May 2012, and its impact on serotype-specific PnPE was 81% (much fewer than serotype 3) and for all PnPE 56.1%; however, for all PE −2.1% due to an increase of PE caused by S. aureus for all but one methicillin-resistant S. aureus (MRSA).

Conclusions:

Following 12.3 years of active surveillance, PCV13 has shown impact on both serotype-specific and all PnPEs; however, an increase of PEs by MRSA has emerged. Continuous surveillance is crucial to establish whether this epidemiological finding is transitory or not.

Trends in the Incidence, Etiology, Treatment, and Outcomes of Pleural Infections in Adults Over a Decade in a Finnish University Hospital

BACKGROUND AND AIMS

The aim of the study was to ascertain changes in the incidence, etiology, treatment, and outcomes of pleural infections over a decade in a Finnish University Hospital.

MATERIALS AND METHODS

All patients treated for pleural infections in Tampere University Hospital during 2000-2008 and 2012-2016 were included. The incidence rates and the epidemiologic data and medical history of patients, etiology of infection, and treatment trends and outcomes were compared between the cohorts.

RESULTS

The incidence of pleural infections increased from 4.4 during 2000-2008 to 9.9 during 2012-2016 per 100.000 patient-years, p < 0.001. The patients in the latter group were older, 63 versus 57 years, p = 0.001, and the prevalence of chronic lung disease, hypertension, heart failure, dyslipidemia, and immunosuppressive medication were higher. The causes of infection remained similar and pneumonia accounted for 70% of all cases. The identification rate of the microbe pathogens increased from 49% to 64%, p = 0.002, while the distribution of identified pathogens was unchanged. More patients in the latter cohort were treated operatively, 88.3% versus 80.9%, p = 0.005, and, in these, the proportion of thoracoscopic surgery was higher, 57.4% versus 8.0%, p < 0.001, and the delay to surgery shorter, 5 versus 7 days, p < 0.001. Radiologic outcomes were similar. The 30-day mortality rate was 3.1% during 2000-2008 and 5.1% during 2012-2016, p = 0.293.

CONCLUSION

The overall incidence of pleural infections has increased significantly while the causes of pleural infections and the distribution of pathogens remain unchanged. Contemporary patients are older with higher prevalence of comorbidities and more frequently undergo thoracoscopic surgery.

Pleural infection: a closer look at the etiopathogenesis, microbiology and role of antibiotics

INTRODUCTION

Pleural infection is a condition that continues to pose a significant challenge to respiratory physicians. We hypothesize that the main barriers to progress include limited understanding of the etiopathogenesis, microbiology,and role of antibiotics in the pleural space. Areas covered: PubMed was searched for articles related to adult pleural infection using the terms 'pleural infection', 'empyema' and 'parapneumonic'. The search focused on relevant literature within the last 10 years, with any older citations used only to display context or lack of progress. Tuberculous pleural infection was excluded. We chose to give specific attention to the etiopathogenesis of pleural infection, including recent advances in diagnostics and biomarkers. We discuss our understanding of the pleural microbiome and rationalize the current use of antibiotics in treating this condition. Expert commentary: Understanding of key events in the development of this condition remains limited. The microbiology is unique compared to the lung, and highly variable. Higher culture yields from pleural biopsy may add new insights into the etiopathogenesis. There is little evidence into achievable effective antibiotic concentration within the pleura. Research into issues including the relevance of biofilm formation and significance of pleural thickening is necessary for treatment progress.

The bacteriology in adult patients with pneumonia and parapneumonic effusions: increased yield with DNA sequencing method

The aim of this study was to use a 16S rDNA sequencing method in combination with conventional culture in patients with parapneumonic effusions (PPE) to evaluate the methods, study the microbiological spectrum, and examine the presence of bacteria within the different stages of PPE. Adults with community-acquired pneumonia (CAP) and PPE (n = 197) admitted to the Departments of Infectious Diseases at four hospitals in Stockholm County during 2011-2014 were prospectively studied. All patients underwent thoracentesis. Twenty-seven non-infectious pleural effusions were used as controls. The pleural samples were analyzed with culture, 16S rDNA sequencing, pH, glucose, and lactate dehydrogenase. Microbiological etiology was found in 99/197 (50%) of the patients with mixed infections in 20 cases. The most common pathogens were viridans streptococci (n = 37) and anaerobic bacteria (n = 40). Among the 152 patients with both methods performed, 26/152 (17%) and 94/152 (62%) had bacteria identified with culture and 16S rDNA sequencing respectively (p < 0.001). In 24/26 (92%) culture-positive cases, the same organism was identified by 16S rDNA. All controls were negative in both methods. Among the patients with complicated PPE and complete sampling, bacteria were found in 69/74 patients (93%), all detected with 16S rDNA sequencing, compared to 23/74 (31%) culture-positive samples (p < 0.001). Compared with culture, 16S rDNA sequencing substantially improved the microbiological yield, a microbiological diagnosis was achieved in almost all patients with complicated PPE, and the specificity seemed to be high. 16S rDNA sequencing should be used together with culture in patients with PPE to guide antibiotic therapy.

Prevalence of Staphylococcus aureus and Use of Antistaphylococcal Therapy in Children Hospitalized with Pneumonia

Within a cohort of >2,000 children hospitalized with community-acquired pneumonia, staphylococcal pneumonia was rare (1%) but associated with adverse in-hospital outcomes. Despite this low prevalence, use of antistaphylococcal antibiotics was common (24%). Efforts are needed to minimize overuse of antistaphylococcal antibiotics while also ensuring adequate treatment for pathogen-specific diseases.

Pneumococcal Vaccination and Pneumonia Associated With Pleural Effusion in a Pediatric Population

OBJECTIVE

The aim was to assess the effect of the nonsystematic pneumococcal conjugate vaccine (PCV) on incidence of pneumonia associated with parapneumonic pleural effusion (PPE) in vaccinated and unvaccinated children.

METHODS

Cases were patients <15 years of age who had been diagnosed with pneumonia associated with PPE in a tertiary hospital in Navarra (Spain) between 1995 and 2014. The population <15 years of age and covered by the public health service was used as reference. The vaccination status of the cases and population was obtained from computerized medical records. Logistic regression analyses included vaccination status, age group and time periods: prevaccine (1995-2001) and vaccination with PCV7 (2002-2010) and PCV13 (2011-2014).

RESULTS

A total of 321 cases of PPE were included. The risk of PPE increased between the prevaccine and PCV7 period (adjusted odds ratio [OR], 3.34; 95% confidence interval [CI]: 2.37-4.71), while vaccination with PCV7 was found to be an independent risk factor (OR, 1.44; 95% CI: 1.09-1.89) in the same analysis. In the PCV13 period, the risk of PPE returned to the prevaccination incidence level among children vaccinated with PCV13 (OR, 1.07; 95% CI: 0.56-2.04), while unvaccinated children (OR, 1.69; 95% CI: 0.96-2.98) and overall those vaccinated with PCV7 (OR, 3.64; 95% CI: 2.15-6.17) maintained an increased risk of PPE.

CONCLUSION

The nonsystematic introduction of PCV7 was followed by an increased incidence of PPE. The subsequent introduction of PCV13 was associated with a return to the incidence level in the prevaccine period, mainly in children vaccinated with PCV13.

When should parapneumonic pleural effusions be drained in children?

Pneumonia is an important health problem in children, and parapneumonic pleural effusion (PPE) is a frequent complication. There is no standard strategy for treating PPE, reflected in the few international guidelines that have been published on the issue. Compared to adults, there is no consensus on the utility of pleural fluid analysis in paediatric PPE. This is because of the lack of good evidence either in favour or against it and the risks of procedural sedation for acquiring pleural fluid for analysis to guide management. In this paper we provide a succinct review of the different approaches to the management of PPE, including diagnosis, pleural fluid analysis (Light's criteria) and treatment, both medical and surgical.

Pneumococcal Vaccines - How Many Serotypes are Enough?

Streptococcus pneumoniae causes meningitis, pneumonia, septicemia, arthritis, sinusitis and otitis media specially in children and over 65 y age groups. It contributes significantly to under-five mortality and morbidity worldwide as well as in India. Use of pneumococcal vaccine seems to be the most effective measure to decrease the disease burden and reduction of under-five mortality. Many countries have already included Pneumococcal Conjugate Vaccines (PCV) in their National Immunization Programmes (NIP). Government of India has announced recently to include PCV13 in NIP in a phased manner. Superiority of a vaccine over the other depends upon serotype coverage, vaccine efficacy, cost effectiveness and safety profile. These facts will be discussed for the vaccines available in India. Further research is warranted to know the disease burden and develop vaccines to have more serotype coverage.

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

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

Impact of the 13-Valent Pneumococcal Conjugate Vaccine on Clinical and Hypoxemic Childhood Pneumonia over Three Years in Central Malawi: An Observational Study

BACKGROUND

The pneumococcal conjugate vaccine's (PCV) impact on childhood pneumonia during programmatic conditions in Africa is poorly understood. Following PCV13 introduction in Malawi in November 2011, we evaluated the case burden and rates of childhood pneumonia.

METHODS AND FINDINGS

Between January 1, 2012-June 30, 2014 we conducted active pneumonia surveillance in children <5 years at seven hospitals, 18 health centres, and with 38 community health workers in two districts, central Malawi. Eligible children had clinical pneumonia per Malawi guidelines, defined as fast breathing only, chest indrawing +/- fast breathing, or, ≥1 clinical danger sign. Since pulse oximetry was not in the Malawi guidelines, oxygenation <90% defined hypoxemic pneumonia, a distinct category from clinical pneumonia. We quantified the pneumonia case burden and rates in two ways. We compared the period immediately following vaccine introduction (early) to the period with >75% three-dose PCV13 coverage (post). We also used multivariable time-series regression, adjusting for autocorrelation and exploring seasonal variation and alternative model specifications in sensitivity analyses. The early versus post analysis showed an increase in cases and rates of total, fast breathing, and indrawing pneumonia and a decrease in danger sign and hypoxemic pneumonia, and pneumonia mortality. At 76% three-dose PCV13 coverage, versus 0%, the time-series model showed a non-significant increase in total cases (+47%, 95% CI: -13%, +149%, p = 0.154); fast breathing cases increased 135% (+39%, +297%, p = 0.001), however, hypoxemia fell 47% (-5%, -70%, p = 0.031) and hospital deaths decreased 36% (-1%, -58%, p = 0.047) in children <5 years. We observed a shift towards disease without danger signs, as the proportion of cases with danger signs decreased by 65% (-46%, -77%, p<0.0001). These results were generally robust to plausible alternative model specifications.

CONCLUSIONS

Thirty months after PCV13 introduction in Malawi, the health system burden and rates of the severest forms of childhood pneumonia, including hypoxemia and death, have markedly decreased.

Population density profiles of nasopharyngeal carriage of 5 bacterial species in pre-school children measured using quantitative PCR offer potential insights into the dynamics of transmission

Bacterial vaccines can reduce carriage rates. Colonization is usually a binary endpoint. Real time quantitative PCR (qPCR) can quantify bacterial DNA in mucosal samples over a wide range. Using culture and single-gene species-specific qPCRs for Streptococcus pneumoniae (lytA), Streptococcus pyogenes (ntpC), Moraxella catarrhalis (ompJ), Haemophilus influenzae (hdp) and Staphylococcus aureus (nuc) and standard curves against log-phase reference strain broth cultures we described frequency and peak density distributions of carriage in nasopharyngeal swabs from 161 healthy 2-4 y old children collected into STGG broth. In general, detection by qPCR and culture was consistent. Discordance mostly occurred at lower detection thresholds of both methods, although PCR assays for S. pyogenes and S. aureus were less sensitive. Density varied across 5-7 orders of magnitude for the 5 species with the abundant species skewed toward high values (modes: S. pneumoniae log3-4, M. catarrhalis & H. influenzae log4-5 CFU/ml broth). Wide ranges of bacterial DNA concentrations in healthy children carrying these bacteria could mean that different individuals at different times vary greatly in infectiousness. Understanding the host, microbial and environmental determinants of colonization density will permit more accurate prediction of vaccine effectiveness.

Changes in empyema among U.S. children in the pneumococcal conjugate vaccine era

BACKGROUND

Parapneumonic empyema, a serious complication of pneumonia, started increasing among U.S. children before the introduction of the 7-valent pneumococcal conjugate vaccine (PCV7) in 2000, and continued afterwards. This increase was due in part to pneumococcal serotypes not included in PCV7 that were included in the new 13-valent (PCV13) vaccine introduced in 2010. We assessed changes in the incidence of empyema hospitalizations among U.S. children after PCV13 introduction.

METHODS

We calculated annualized empyema hospitalization rates among U.S. children <18years using Nationwide Inpatient Sample and Census data (1997-2013) for four periods based on PCV7 and PCV13 introductions. Relative rates (RR) and 95% confidence intervals (CI) were calculated by age group and sex, comparing PCV7 [early-PCV7 (2001-2005) and late-PCV7 (2006-2009)] and PCV13 (2011-2013) periods with the pre-PCV7 period (1997-1999). Secondary analyses examined changes in pneumococcal, streptococcal, staphylococcal and unspecified empyema.

RESULTS

Among children <18years of age, annualized empyema hospitalization rates peaked at 3.6 per 100,000 in the late-PCV7 period compared with 2.1 per 100,000 in the pre-PCV7 period [RR: 1.70 (95% CI: 1.11-2.60)]. However, annualized rates in the post-PCV13 period declined to 2.0 per 100,000, similar to rates in the pre-PCV7 period. Empyema rates among children <2years were lower in the post-PCV13 period compared to the pre-PCV7 period [RR: 0.77 (95% CI: 0.61-0.96)], but rates in the two periods among children 2-4 and 5-17years were similar. Most empyema were of unspecified etiology. Pneumococcal and unspecified empyema declined after PCV13 introduction.

CONCLUSIONS

Although empyema hospitalization rates among U.S. children peaked after PCV7 introduction, rates decreased substantially following the introduction of PCV13.

The Role of DNA Amplification and Cultural Growth in Complicated Acute Appendicitis

Bacterial growth of peritoneal fluid specimens obtained during surgical procedures for acute appendicitis may be useful to optimize further antibiotic therapy in complicated cases. DNA amplification represents a fast technique to detect microbial sequences. We aimed to compare the potential of DNA amplification versus traditional bacterial growth culture highlighting advantages and drawbacks in a surgical setting. Peritoneal fluid specimens were collected during surgery from 36 children who underwent appendectomy between May and December 2012. Real-time polymerase chain reaction (RT-PCR) and cultures were performed on each sample. RT-PCR showed an amplification of 16S in 18/36 samples, Escherichia coli (in 7 cases), Pseudomonas aeruginosa (3), Fusobacterium necrophorum (3), Adenovirus (2), E.coli (1), Klebsiella pneumoniae (1), Serratia marcescens/Enterobacter cloacae (1). Bacterial growth was instead observed only in four patients (3 E.coli and 1 P.aeruginosa and Bacteroides ovatus). Preoperative C-reactive protein and inflammation degree, the most reliable indicators of bacterial translocation, were elevated as expected. DNA amplification was a quick and useful method to detect pathogens and it was even more valuable in detecting aggressive pathogens such as anaerobes, difficult to preserve in biological cultures; its drawbacks were the lack of biological growths and of antibiograms. In our pilot study RT-PCR and cultures did not influence the way patients were treated.

Pleural effusion with negative culture: a challenge for pneumococcal diagnosis in children

BACKGROUND

Pneumococcal parapneumonic effusion seems to be increasing in children in the postvaccine era and is frequently associated with negative culture. Due to the low yield of culture, culture-independent tools are evaluated.

METHODS

Culture-negative pleural fluid specimens from 38 children with parapneumonic effusion were examined for pneumococcal lytA by quantitative polymerase chain reaction (qPCR) and soluble antigen (C-polysaccharide) using an immunochromatographic test (BinaxNow Streptococcus pneumoniae).

RESULTS

In 81% (30/37) and 63% (24/38) of the specimens, a positive result was obtained by qPCR and antigen detection, respectively. Most mismatches were observed in specimens with low quantities of pneumococcal DNA and a negative antigen test.

CONCLUSIONS

Our results suggest an imperfect relationship between the 2 described methods. The immunochromatographic assay is a simple diagnostic tool, which can be used when resources are limited, and even after antibiotic use, but negative results may require confirmation through a more sensitive test, such as qPCR.

Detection of bacterial pathogens in synovial and pleural fluid with the FilmArray Blood Culture Identification System

We report the use of FilmArray Blood Culture Identification (BCID) multiplex PCR system for pathogen detection from a child with septic arthritis that Streptococcus pyogenes was identified directly from synovial fluid and a child with complicated pneumonia with pleural effusion that Streptococcus pneumoniae was identified from pleural fluid.

Staphylococcus aureus Community-acquired Pneumonia: Prevalence, Clinical Characteristics, and Outcomes

BACKGROUND

Prevalence of Staphylococcus aureus community-acquired pneumonia (CAP) and its clinical features remain incompletely understood, complicating empirical selection of antibiotics.

METHODS

Using a multicenter, prospective surveillance study of adults hospitalized with CAP, we calculated the prevalence of methicillin-resistant S. aureus (MRSA) and methicillin-susceptible S. aureus (MSSA) among all CAP episodes. We compared the epidemiologic, radiographic, and clinical characteristics of S. aureus CAP (per respiratory or blood culture) with those of pneumococcal (per respiratory or blood culture or urine antigen) and all-cause non-S. aureus CAP using descriptive statistics.

RESULTS

Among 2259 adults hospitalized for CAP, 37 (1.6%) had S. aureus identified, including 15 (0.7%) with MRSA and 22 (1.0%) with MSSA; 115 (5.1%) had Streptococcus pneumoniae Vancomycin or linezolid was administered to 674 (29.8%) patients within the first 3 days of hospitalization. Chronic hemodialysis use was more common among patients with MRSA (20.0%) than pneumococcal (2.6%) and all-cause non-S. aureus (3.7%) CAP. Otherwise, clinical features at admission were similar, including concurrent influenza infection, hemoptysis, multilobar infiltrates, and prehospital antibiotics. Patients with MRSA CAP had more severe clinical outcomes than those with pneumococcal CAP, including intensive care unit admission (86.7% vs 34.8%) and in-patient mortality (13.3% vs 4.4%).

CONCLUSIONS

Despite very low prevalence of S. aureus and, specifically, MRSA, nearly one-third of adults hospitalized with CAP received anti-MRSA antibiotics. The clinical presentation of MRSA CAP overlapped substantially with pneumococcal CAP, highlighting the challenge of accurately targeting empirical anti-MRSA antibiotics with currently available clinical tools and the need for new diagnostic strategies.