Epidemiology of viral respiratory infections in children undergoing heart surgery

Application value of metagenomics next-generation sequencing in the diagnosis of respiratory virus infection after congenital heart surgery

Background

Timely and accurate pathogen diagnosis can be challenging in children who contract a respiratory virus following congenital heart surgery (CHS). This often results in suboptimal drug use and treatment delays. Metagenomics next-generation sequencing (mNGS) is a swift, efficient, and unbiased method for obtaining microbial nucleic acid sequences. This technology holds promise as a comprehensive diagnostic tool, especially for pathogens undetectable by traditional methods. However, the efficacy of mNGS in the context of congenital heart disease infections remains uncertain. This study aimed to explore the diagnostic value of mNGS for respiratory virus infections post-CHS.

Methods

We conducted a retrospective analysis of patients who developed respiratory tract infections post-CHS and were admitted to our cardiac center between July 2021 and December 2022. The patients were categorized into the following two groups based on the diagnostic method used: (I) the mNGS group (comprising 62 patients); and (II) the conventional microbiological test (CMT) group (comprising 70 patients). Bronchoalveolar lavage fluid (BALF) samples from these patients were tested to identify pathogens.

Results

The mNGS group had significantly higher detection rates for both viral infections and mixed viral infections than the CMT group (56.45% vs. 17.14%, P<0.001, and 80.00% vs. 16.67%, P<0.001, respectively). In the mNGS group, 19.35% of the patients received antiviral therapy, and 61.29% received an anti-infective regimen adjustment. Conversely, in the CMT group, only 4.29% received antiviral therapy, and 28.57% received an anti-infective regimen adjustment. A higher percentage of patients showed improved respiratory symptoms in the mNGS group than the CMT group (74.19% vs. 44.29%, P=0.001). Additionally, the mNGS group had a shorter duration of mechanical ventilation and a reduced length of stay in the cardiac intensive care unit than the CMT group (P=0.012).

Conclusions

Using mNGS for BALF enhances the detection of respiratory viral infections and coexisting viral infections post-CHS. This facilitates more precise treatment strategies and could potentially lead to improved patient outcomes.

PCR-based diagnosis of respiratory virus in postsurgical septic patients: A preliminary study before SARS-CoV-2 pandemic

Respiratory viruses are part of the normal microbiota of the respiratory tract, which sometimes cause infection with/without respiratory insufficiency and the need for hospital or ICU admission. The aim of this study is to determine the prevalence of respiratory viruses in nontransplanted postoperative septic patients as well as lymphocyte count influence in their presence and its relationship to mortality. 223 nontransplanted postsurgical septic patients were recruited on the Intensive Care Unit (ICU) at Hospital Clínico Universitario de Valladolid prior to the SARS-COV-2 pandemic. Patients were split into 2 groups according to the presence/absence of respiratory viruses. Multivariate logistic regression analysis was used to identify independent factors related to positive respiratory virus PCR test. Respiratory viruses were isolated in 28.7% of patients. 28-day mortality was not significantly different between virus-positive and virus-negative groups. Logistic regression analysis revealed that lymphocyte count ≤ 928/µl is independently associated with a positive PCR result [OR 3.76, 95% CI (1.71-8.26), P = .001] adjusted by platelet count over 128,500/µL [OR 4.27, 95% CI (1.92-9.50) P < .001] and the presence of hypertension [OR 2.69, 95% CI (1.13-6.36) P = .025] as confounding variables. Respiratory viruses' detection by using PCR in respiratory samples of nontransplanted postoperative septic patients is frequent. These preliminary results revealed that the presence of lymphopenia on sepsis diagnosis is independently associated to a positive virus result, which is not related to a higher 28-day mortality.

Comparative study of different SARS-CoV-2 diagnostic techniques

The rapid spread of SARS-CoV-2 led to the necessity of developing diagnostic tests for rapid virus detection. Many commercial platforms have appeared and have been approved for this purpose. In this study, 95 positive and 5 negative retrospective samples were analyzed by 4 different commercial RT-qPCR kits (TaqMan 2019nCoV Assay, Allplex™SARS-COV-2 Assay, FTD SARS-COV-2 Assay and qCOVID-19). The Hologic Aptima SARS-COV-2 and the Clart-COVID-19 system were also tested. serial dilutions of SARS-COV-2 standard control were included for sensitivity analysis. Among the qPCR tested qCOVID19 and Allplex™SARS-COV-2 Assay were both able to detect all the clinical samples included in the study. All four qPCR evaluated showed high sensitivity for samples with Ct<33. Clart-COVID-19 microarrays detected all samples and controls used in this study whereas Hologic Aptima Panther failed with one of the clinical samples. However, the main problem with this system was the number of invalidated samples despite avoiding the use of medium with guanidine isothiocyanate as recommended by the manufacturer. All the techniques tested were of value for SARS-CoV-2 detection.