High frequency of Chlamydia pneumoniae and risk factors in children with acute respiratory infection

Chlamydophila pneumoniae-associated community-acquired pneumonia in paediatric patients of a tertiary care hospital in Mexico: molecular diagnostic and clinical insights

Chlamydophila pneumoniae is a cause of community-acquired pneumonia (CAP) and responsible for 1-2% of cases in paediatric patients. In Mexico, information on this microorganism is limited. The aim of this study was to detect C. pneumoniae using two genomic targets in a real-time PCR and IgM/IgG serology assays in paediatric patients with CAP at a tertiary care hospital in Mexico City and to describe their clinical characteristics, radiological features, and outcomes. A total of 154 hospitalized patients with diagnosis of CAP were included. Detection of C. pneumoniae was performed by real-time PCR of the pst and arg genes. Complete blood cell count, C-reactive protein measurement and IgM and IgG detection were performed. Clinical-epidemiological and radiological data from the patients were collected. C. pneumoniae was detected in 25 patients (16%), of whom 88% had underlying disease (P = 0.014). Forty-eight percent of the cases occurred in spring, 36% in girls, and 40% in children older than 6 years. All patients had cough, and 88% had fever. Interstitial pattern on chest-X-ray was the most frequent (68%), consolidation was observed in 32% (P = 0.002). IgM was positive in 7% and IgG in 28.6%. Thirty-six percent presented complications. Four percent died. A high proportion showed co-infection with Mycoplasma pneumoniae (64%). This is the first clinical report of C. pneumoniae as a cause of CAP in Mexican paediatric patients, using two genomic target strategy and serology. We found a frequency of 16.2% with predominance in children under 6 years of age. In addition; cough and fever were the most common symptoms. Early detection of this pathogen allows timely initiation of specific antimicrobial therapy to reduce development of complications. This study is one of the few to describe the presence of C. pneumoniae in patients with underlying diseases.

Prevalence of atypical pathogens in patients with severe pneumonia: a systematic review and meta-analysis

OBJECTIVES

We aimed to summarise the prevalence of atypical pathogens in patients with severe pneumonia to understand the prevalence of severe pneumonia caused by atypical pathogens, improve clinical decision-making and guide antibiotic use.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

PubMed, Embase, Web of Science and Cochrane Library were searched through November 2022.

ELIGIBILITY CRITERIA

English language studies enrolled consecutive cases of patients diagnosed with severe pneumonia, with complete aetiological analysis.

DATA EXTRACTION AND SYNTHESIS

We conducted literature retrieval on PubMed, Embase, Web of Science and The Cochrane Library to estimate the prevalence of Chlamydia, Mycoplasma and Legionella in patients with severe pneumonia. After double arcsine transformation of the data, a random-effects model was used for meta-analyses to calculate the pooled prevalence of each pathogen. Meta-regression analysis was also used to explore whether the region, different diagnostic method, study population, pneumonia categories or sample size were potential sources of heterogeneity.

RESULTS

We included 75 eligible studies with 18 379 cases of severe pneumonia. The overall prevalence of atypical pneumonia is 8.1% (95% CI 6.3% to 10.1%) In patients with severe pneumonia, the pooled estimated prevalence of Chlamydia, Mycoplasma and Legionella was 1.8% (95% CI 1.0% to 2.9%), 2.8% (95% CI 1.7% to 4.3%) and 4.0% (95% CI 2.8% to 5.3%), respectively. We noted significant heterogeneity in all pooled assessments. Meta-regression showed that the pneumonia category potentially influenced the prevalence rate of Chlamydia. The mean age and the diagnostic method of pathogens were likely moderators for the prevalence of Mycoplasma and Legionella, and contribute to the heterogeneity of their prevalence.

CONCLUSIONS

In severe pneumonia, atypical pathogens are notable causes, especially Legionella. The diagnostic method, regional difference, sample size and other factors contribute to the heterogeneity of prevalence. The estimated prevalence and relative heterogeneity factors can help with microbiological screening, clinical treatment and future research planning.

PROSPERO REGISTRATION NUMBER

CRD42022373950.

Diagnostic Value of the Triple Combination of Serum Heparin-Binding Protein, Procalcitonin, and C-Reactive Protein in Children with Acute Bacterial Upper Respiratory Tract Infection

To investigate the role of the triple combination serum heparin-binding protein (HBP), procalcitonin (PCT), and C-reactive protein (CRP) in children with acute bacterial upper respiratory tract infection (ABURTI). A total of 130 children with upper respiratory tract infection admitted to the Department of Pediatrics of Fujian Maternity and Child Health Hospital from September 2019 to January 2021 were selected as the research group. According to the results of pathogenic analysis, children were further subdivided into a bacterial infection group (n = 67) and a viral infection group (n = 63). Additionally, 65 children who underwent physical examinations in our hospital during the same period were collected and included into the control group (n = 65). All patients selected were treated with cefixime granules orally for 5 days. Serum HBP level, serum PCT level, and serum CRP level were measured by double antibody Sandwich Enzyme Linked Immunosorbent Assay (ELISA), fluorescence method, and immunoturbidimetric assay, respectively. The expression levels of the three indicators in the serum of all subjects were compared, and the receiver operating characteristic (ROC) curve was used to analyze their diagnostic value in children with ABURTI. Furthermore, according to clinical efficacy of children with bacterial infections, they were divided into a good efficacy group (markedly effective) and a poor efficacy group (effective + ineffective) to compare serum HBP, PCT, and CRP levels between the two groups. The ROC curve was drawn to analyze the value of the three indicators in predicting the curative effect in children with ABURTI. Pearson test was used to analyze the correlation among the expression of HBP, PCT, and CRP. Results showed that the expression levels of HBP, PCT, and CRP in the serum of children in the bacterial infection group were significantly higher than those in the other two groups. The positive rates of HBP, PCT, and CRP in children in the bacterial infection group were also significantly higher than those of the other two groups. The area under the curve (AUC) of the combined diagnosis of HBP, PCT, and CRP was 0.973, which was significantly higher than that of the single detection by any of the three indicators, which were 0.849, 0.819, and 0.854, respectively. The expression levels of HBP, PCT, and CRP in the serum of children in the good efficacy group were significantly lower than those in the poor efficacy group, and the AUC of the triple combination for predicting treatment efficacy was 0.959. Pearson test showed that there was a positive correlation between the serum expression of HBP, PCT, and CRP in children. HBP, PCT, and CRP were highly correlated in children with ABURTI, and their combined detection was of high diagnostic value among ABURTI patients, indicating that the three were expected to become potential indicators for efficacy prediction.