Respiratory Tract Samples Research Articles

Clinical evaluation of a multiplex real-timeRT-PCR assay for detection of SARS-CoV-2 in individual and pooled upper respiratory tract samples.

The aim of this study was to identify and validate a sensitive, high-throughput, and cost-effective SARS-CoV-2 real-time RT-PCR assay to be used as a surveillance and diagnostic tool for SARS-CoV-2 in a university surveillance program. We conducted a side-by-side clinical evaluation of a newly developed SARS-CoV-2 multiplex assay (EZ-SARS-CoV-2 Real-Time RT-PCR) with the commercial TaqPath COVID-19 Combo Kit, which has an Emergency Use Authorization from the FDA. The EZ-SARS-CoV-2 RT-PCR incorporates two assays targeting the SARS-CoV-2 N gene, an internal control targeting the human RNase P gene, and a PCR inhibition control in a single reaction. Nasopharyngeal (NP) and anterior nares (AN) swabs were tested as individuals and pools with both assays and in the ABI 7500 Fast and the QuantStudio 5 detection platforms. The analytical sensitivity of the EZ-SARS-CoV-2 RT-PCR assay was 250 copies/ml or approximately 1.75 genome copy equivalents per reaction. The clinical performance of the EZ-SARS-CoV-2 assay was evaluated using NP and AN samples tested in other laboratories. The diagnostic sensitivity of the assay ranged between 94 and 96% across the detection platforms, and the diagnostic specificity was 94.06%. The positive predictive value was 94%, and the negative predictive value ranged from 94 to 96%. Pooling five NP or AN specimens yielded 93% diagnostic sensitivity. The overall agreement between these SARS-CoV-2 RT-PCR assays was high, supported by a Cohen’s kappa value of 0.93. The EZ-SARS-CoV-2 RT-PCR assay performance attributes of high sensitivity and specificity with AN sample matrix and pooled upper respiratory samples support its use in a high-throughput surveillance testing program.Supplementary InformationThe online version contains supplementary material available at 10.1007/s00705-021-05148-1.

Molecular exploration for Mycoplasma amphoriforme, Mycoplasma fermentans and Ureaplasma spp. in patient samples previously investigated for Mycoplasma pneumoniae infection

ObjectivesTo determine the presence and genotypic macrolide susceptibility of Mycoplasma amphoriforme, and the presence of Ureaplasma spp. and Mycoplasma fermentans among clinical samples from England previously investigated for Mycoplasma pneumoniae. MethodsQuantitative and conventional PCR methods were used to retrospectively screen a collection of 160 clinical samples previously submitted to Public Health England (PHE) for the detection of M. pneumoniae between October 2016 and December 2017. Samples which were positive for M. amphoriforme DNA were further investigated for mutations associated with genotypic macrolide resistance by sequencing domain V of the 23s rRNA. ResultsM. amphoriforme was detected in 10/160 samples (6.3%), Ureaplasma parvum was detected in 4/160 samples (2.5%), and M. fermentans was not detected in any samples (0/160). Of the nine individuals (two samples were from the same patient) in which M. amphoriforme was detected, eight were male (age range 10–60 years) and one was female (age range 30–40 years). One individual with cystic fibrosis was positive for both M. amphoriforme and U. parvum. All M. amphoriforme DNA was genotypically susceptible to macrolides. ConclusionsMycoplasma amphoriforme was found in clinical samples, including lower respiratory tract samples of patients with pneumonia. In the absence of other respiratory pathogens, these data suggest a potential role for this organism in human disease, with no evidence of acquired macrolide resistance. Ureaplasma parvum was detected in cerebrospinal fluid and respiratory tract samples. These data suggest that there is a need to consider these atypical respiratory pathogens in future diagnostic investigations.

Nanoparticle transfer biosensors for the non-invasive detection of SARS-CoV-2 antigens trapped in surgical face masks

Detecting SARS-CoV-2 antigens in respiratory tract samples has become a widespread method for screening new SARS-CoV-2 infections. This requires a nasopharyngeal swab performed by a trained healthcare worker, which puts strain on saturated healthcare services. In this manuscript we describe a new approach for non-invasive COVID-19 diagnosis. It consists of using mobile biosensors for detecting viral antigens trapped in surgical face masks worn by patients. The biosensors are made of filter paper containing a nanoparticle reservoir. The nanoparticles transfer from the biosensor to the mask on contact, where they generate colorimetric signals that are quantified with a smartphone app. Sample collection requires wearing a surgical mask for 30 min, and the total assay time is shorter than 10 min. When tested in a cohort of 27 patients with mild or no symptoms, an area under the receiving operating curve (AUROC) of 0.99 was obtained (96.2 % sensitivity and 100 % specificity). Serial measurements revealed a high sensitivity and specificity when masks were worn up to 6 days after diagnosis. Surgical face masks are inexpensive and widely available, which makes this approach easy to implement anywhere. The excellent sensitivity, even when tested with asymptomatic patient samples, along with the mobile detection scheme and non-invasive sampling procedure, makes this biosensor design ideal for mass screening.

The human microbiome and COVID-19: A systematic review.

Human microbiotas are communities of microorganisms living in symbiosis with humans. They play an important role in the host immune response to respiratory viral infection. However, evidence on the human microbiome and coronavirus disease (COVID-19) relationship is insufficient. The aim of this systematic literature review was to evaluate existing evidence on the association between the microbiome and COVID-19 in humans and summarize these data in the pandemic era. We conducted a systematic literature review on the association between the microbiome and COVID-19 in humans by searching PubMed, Embase, and the Cochrane Library, CINAHL, and Web of Science databases for articles in English published up to October 31, 2020. The results were analyzed qualitatively. This study is registered with PROSPERO (CRD42020195982). Of the 543 articles identified by searching databases, 16 in line with the research objectives were eligible for qualitative review: eight sampled the microbiome using stool, four using nasopharyngeal or throat swab, three using bronchoalveolar lavage fluid, and one using lung tissue. Fecal microbiome dysbiosis and increased opportunistic pathogens were reported in COVID-19 patients. Several studies suggested the dysbiosis in the lung microbiome of COVID-19 patients with an abundance of opportunistic pathogens using lower respiratory tract samples. The association between COVID-19 severity and the human microbiome remains uncertain. The human fecal and respiratory tract microbiome changed in COVID-19 patients with opportunistic pathogen abundance. Further research to elucidate the effect of alternation of the human microbiome in disease pathogenesis is warranted.

Clinico-microbiological description and evaluation of rapid lateral flow immunoassay and PCR for detection of Burkholderia pseudomallei from patients hospitalized with sepsis and pneumonia: A twenty-one months study from Odisha, India

Establishing a diagnosis of melioidosis based on clinical grounds is difficult in hospitalized patients with sepsis or community acquired pneumonia (CAP). We aimed to ascertain the prevalence, clinico-epidemiological and laboratory profile of melioidosis in hospitalized patients with sepsis or CAP, and to evaluate the diagnostic utility of rapid lateral flow immunoassay (LFI) and PCR in comparison with culture. In all patients with sepsis or CAP, blood, sputum/throat swab, and urine sample were subjected to culture along with other samples based on clinical presentation. In addition, PCR assay targeting the type III secretion system 1 (TTS1) and LFI was performed. Thirty-three (33/196, 17%) out of the total 196 cases were diagnosed as melioidosis by culture. The prevalence of melioidosis in patients who had only sepsis without CAP, had both sepsis and CAP, had CAP without sepsis was 31% (26/84), 22 % (4/18) and 3%(3/94) respectively.All the LFI or PCR positive cases were culture positive from at least one or more samples (blood/sputum/urine/pus). The sensitivity, specificity, positive predictive value and negative predictive value of TTS1 PCR was 78% (18/23 melioidosis patients), 100% (34/34 non-melioidosis patients), 100% (18/18 melioidosis patients) and 87% (34/39 non-melioidosis patients). The sensitivity, specificity, positive predictive value and negative predictive value of Rapid LFI was 91% (21/23 melioidosis patients), 100% (22/22 non-melioidosis patients), 100% (21/21 melioidosis patients) and 91% (22/24 non-melioidosis patients). On sample wise stratification of LFI and TTS1 with respect to culture, plasma/serum samples showed the highest discordance by PCR (9/55, 16.3%) and LFI (11/35, 31.4%). The lowest discordance was noted in respiratory tract samples (2/32, 6.2%) by PCR and pus/body fluids samples (2/14, 14.2%) by LFI and these findings are in line with previous published literature. The clinical utility of PCR and LFI needs to be further validated in a large scale study for early diagnosis of septicaemic melioidosis.

SARS-CoV-2 Gastrointestinal Infection Prolongs the Time to Recover From COVID-19.

Objectives: We previously reported that SARS-CoV-2 infects the gastrointestinal (GI) epithelium. In this study, we aimed to explore the impact of SARS-CoV-2 GI infection on clinical outcomes of COVID-19.Materials and Methods: For this retrospective cohort study, 104 patients with COVID-19 were classified into a SARS-CoV-2 GI infection group and a non-infection group. The primary endpoint was the time of negative conversion of SARS-CoV-2 RNA in respiratory tract samples. The secondary outcome was the time of hospitalization for COVID-19.Results: Patients with SARS-CoV-2 GI infection had a longer duration of positive SARS-CoV-2 RNA in respiratory tract samples (median 12.0 days [95% CI: 10.0–13.2] vs. 9.0 days [95% CI: 7.5–10.5]; HR 0.575 [95% CI: 0.386–0.857]; P = 0.003) and hospitalization (median 28.0 days [95% CI: 23.2–32.8] vs. 15.0 days [95% CI: 13.6–16.4]; HR 0.149 [95% CI: 0.087–0.252]; P < 0.001) than patients without SARS-CoV-2 GI infection. Subgroup analyses for sex, age, epidemiological history, clinical classification and antiviral treatment showed consistent results.Conclusion: Our study indicates that SARS-CoV-2 GI infection prolongs the duration of SARS-CoV-2 shedding and hospitalization in the patients with COVID-19. More attention should be paid to SARS-CoV-2 GI infection of COVID-19 and fecal SARS-CoV-2 RNA test should be completed in time.

Visualization of Respiratory Commensal Bacteria in Context of Their Natural Host Environment.

Commensal microbes are an integral component of mammalian physiology. 16S rRNA gene-specific next generation sequencing from DNA of total organs, swabs or lavages has revolutionized the characterization of bacterial communities in virtually every ecological niche of the body. Culturomics, next allowed the isolation and characterization of commensal bacteria in the lab and the establishment of artificial communities of bacteria, which were eventually reintroduced in model organisms. Spatial organization of microbiota within a given host environment is critical to the physiological or pathological phenotypes provoked by commensal microbiota. In situ hybridization (ISH) is a complementary technique to sequencing and culturing to visualize the presence of individual bacterial operational taxonomic unit (OTUs) in context of the colonized organ. We recently applied highly sensitive in situ RNA hybridization to detection of commensal bacteria in low abundance respiratory tract samples of mice housed under specific pathogen free conditions. This technique allows species-specific detection of living bacteria using RNAScopeTM technology, while preserving the natural environment of the organ. We here provide a detailed step-by-step protocol describing the detection of commensal lung bacteria in respiratory tissue.

Characterization of Streptococcus pneumoniae detected in clinical respiratory tract samples in southern Sweden 2 to 4 years after introduction of PCV13

To determine the serotype distribution and antimicrobial resistance of Streptococcus pneumoniae associated with mucosal infections in patients of all ages, 2 to 4 years after the transition from a 10-valent pneumococcal conjugate vaccine (PCV10) to PCV13 in the childhood immunization programme. Background information and antimicrobial susceptibility data regarding all respiratory tract, middle ear, and conjunctival samples positive for growth of S. pneumoniae (n=2,131) were collected during 18 months in 2016-2018. Available corresponding bacterial isolates were serotyped by PCR and/or antisera (n=1,858). In total, 17% of isolates were covered by PCV13, predominantly represented by serotypes 3 (9%) and 19A (5%). The most common nonvaccine serotypes were 11A (10%), 23B (10%), 15A (6%) and 35F (5%). Isolates exhibiting serotype 15A or 23B were often multidrug-resistant (21%) or penicillin nonsusceptible (38%), respectively. The overall proportion of serotype 19A was halved compared to a previous observation period when PCV10 was used (years 2011-2013), suggesting herd protection related to PCV13. The proportion of serotype 3 was, however, unchanged. Despite most nonvaccine serotypes causing mucosal infections have a low invasive potential, certain antibiotic resistant serotypes may pose a clinical problem.

Respiratory bacterial co-infections in intensive care unit-hospitalized COVID-19 patients: Conventional culture vs BioFire FilmArray pneumonia Plus panel

The prevalence and microbiology of concomitant respiratory bacterial infections in patients with SARS-CoV-2 infection are not yet fully understood. In this retrospective study, we assessed respiratory bacterial co-infections in lower respiratory tract samples taken from intensive care unit-hospitalized COVID-19 patients, by comparing the conventional culture approach to an innovative molecular diagnostic technology.A total of 230 lower respiratory tract samples (i.e., bronchial aspirates or bronchoalveolar lavages) were taken from 178 critically ill COVID-19 patients. Each sample was processed by a semi-quantitative culture and by a multiplex PCR panel (FilmArray Pneumonia Plus panel), allowing rapid detection of a wide range of clinically relevant pathogens and a limited number of antimicrobial resistance markers.More than 30% of samples showed a positive bacterial culture, with Pseudomonas aeruginosa, Klebsiella pneumoniae and Staphylococcus aureus the most detected pathogens.FilmArray showed an overall sensitivity and specificity of 89.6% and 98.3%, respectively, with a negative predictive value of 99.7%. The molecular test significantly reduced the turn-around-time (TAT) and increased the rates of microbial detection. Most cases missed by culture were characterized by low bacterial loads (104–105 copies/mL). FilmArray missed a list of pathogens not included in the molecular panel, especially Stenotrophomonas maltophilia (8 cases).FilmArray can be useful to detect bacterial pathogens in lower respiratory tract specimens of COVID-19 patients, with a significant decrease of TAT. The test is particularly useful to rule out bacterial co-infections and avoid the inappropriate prescription of antibiotics.

Using preprints in evidence synthesis: Commentary on experience during the COVID-19 pandemic

Using preprints in evidence synthesis: Commentary on experience during the COVID-19 pandemic

Characteristics and Antibiotic Resistance of Haemophilus influenzae in Children with Lower Respiratory Tract Infection in Chengdu, China

Background: Haemophilus influenzae is an opportunistic pathogen of the human respiratory tract. Haemophilus influenzae can cause not only respiratory tract infection in children but also otitis media, epiglottitis and sinusitis. With the widespread use of antibiotics, the positive rate of β-lactamase in H. influenzae is increasing, and the rate of antimicrobial resistance is also increasing, which increases the difficulty of clinical treatment. Objectives: To study the infection characteristics of patients and the antibiotic resistance of H. influenzae in lower respiratory tract samples of children in Chengdu, so as to provide a reference for its clinical diagnosis and the rational use of antibiotics. Methods: Sputum samples of 15891 children aged 0-14 years with lower respiratory tract infection were collected. Haemophilus influenzae was cultured and identified, its drug susceptibility tested, and the results determined according to the guidelines of CLSI 2020. Results: A total of 15891 clinical isolate strains in sputum were detected for drug sensitivity from December 2018 to January 2020, of which 5488 were H. influenzae, accounting for 34.54% (5488/15891). The sex of children infected with H. influenzae was not skewed (P &gt; 0.05). The detection rate of H. influenzae was the highest in children aged 7 - 11 months, and the lowest was in the age group ≤ 28 d. The detection rate was the highest in spring and the lowest in autumn. The positive rate of β-lactamase was 92.0%, the resistance rate to ampicillin was 92.0%, the sensitivity to amoxicillin/clavulanate was 70.2%, and the sensitivity to cefotaxime, ofloxacin, tetracycline, chloramphenicol, and rifampicin was more than 90.0%. Conclusions: Children aged 7 months to 14 years were generally susceptible to H. influenzae in spring, and the positive rate of β-lactamase was high. Doctors should refer to the infection characteristics and drug resistance of H. influenzae and choose antibiotics correctly to better control the infection.

The utility of paired upper and lower respiratory tract sampling for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) testing in patients with artificial airways.

Early in the coronavirus disease 2019 (COVID-19) pandemic, the CDC recommended collection of a lower respiratory tract (LRT) specimen for severe acute respiratory coronavirus virus 2 (SARS-CoV-2) testing in addition to the routinely recommended upper respiratory tract (URT) testing in mechanically ventilated patients. Significant operational challenges were noted at our institution using this approach. In this report, we describe our experience with routine collection of paired URT and LRT sample testing. Our results revealed a high concordance between the 2 sources, and that all children tested for SARS-CoV-2 were appropriately diagnosed with URT testing alone. There was no added benefit to LRT testing. Based on these findings, our institutional approach was therefore adjusted to sample the URT alone for most patients, with LRT sampling reserved for patients with ongoing clinical suspicion for SARS-CoV-2 after a negative URT test.

The extent of infectious SARS-CoV-2 shedding in an Argentinean cohort.

BackgroundTo analyze the infectious extent of severe acute respiratory syndrome coronavirus 2 (SARS-COV-2) in different settings where prevention strategies are critical to limit infection spread, we evaluated SARS-COV-2 viability to guide public health policies regarding isolation criteria and infection control.MethodsWe attempted viral isolation in 82 nasopharyngeal swabs from 72 patients with confirmed SARS-COV-2 infection. Study population was divided into four groups: (i) Patients during the first week of symptoms; (ii) Patients with prolonged positive PCR; (iii) Healthcare workers from a hospital participating of an outbreak investigation, with SARS-COV-2 infection confirmed by reverse transcriptase polymerase chain reaction (RT-PCR) and (iv) Recipients of convalescent immune plasma (CIP).Vero Cl76 cell-line (ATCC CRL-587) was used in assays for virus isolation. Plasma samples of CIP recipients were also tested with plaque-reduction neutralization test.ResultsWe obtained infectious SARS-COV-2 isolates from 15/84 nasopharyngeal swabs. The virus could not be isolated from upper respiratory tract samples collected 10-day after onset of symptoms (AOS) in patients with mild–moderate disease.ConclusionThe knowledge of the extent of SARS-CoV-2 infectivity AOS is relevant for effective prevention measures. This allows to discuss criteria for end isolation despite persistence of positive PCR and improve timing for hospital discharge with consequent availability of critical beds.

Prevalence and antibiotic resistance of bacterial pathogens in respiratory tract samples of geriatric patients

Background/Aim: The frequency and severity of respiratory tract infections increase with aging. The aim of this study was to determine the bacterial profile of respiratory tract samples in geriatric patients and evaluate the antibiotic susceptibility patterns of the pathogens. Methods: In this cross-sectional study, a total of 509 clinical samples which were obtained from 302 geriatric patients over 65 years of age and sent to the microbiology laboratory between June 2019-January 2021 were investigated retrospectively. The identification and antibiotic susceptibilities of strains were evaluated with BD-Phoenix-100 fully automated microbiology system. Results: Of the 302 geriatric patients, 166 (%55) were males and 136 (%45) were females. The most isolated pathogens were Klebsiella pneumoniae (25.3%) Pseudomonas aeruginosa (22.5%) and Acinetobacter baumannii (10.2%), Corynebacterium striatum (7.3%), Escherichia coli (6.4%), Staphylococcus aureus (6.4%) and coagulase-negative staphylococci (4.2%). The production of ESBL in Klebsiella pneumoniae strains (52.3%) was higher than in Escherichia coli (41%) strains. All Corynebacterium striatum samples were resistant to ciprofloxacin, tetracycline, rifampin, and penicillin. Methicillin resistance among Staphylococcus aureus (MRSA) isolates was 22.7% and they were 100% susceptible to vancomycin and teicoplanin. Above 90% of K. pneumoniae, P. aeruginosa and A. baumannii positive patients were hospitalized in intensive care units (P<0.05). The tobramycin-resistant E. coli and colistin-resistant A. baumannii rates were highest between 85-99 years of age (P<0.05). Conclusion: K. pneumoniae, P. aeruginosa and A. baumannii were the most common pathogens in respiratory tract samples in geriatric patients, especially those hospitalized in the intensive care units. The antimicrobial resistance rates were higher in patients aged ≥85 years. Vancomycin and teicoplanin were the most effective antibiotics against MRSA. It is thought that the results will be useful in the preparation of treatment protocols and guiding physicians about the correct use of antibiotics.

Detectable respiratory SARS-CoV-2 RNA is associated with low vitamin D levels and high social deprivation.

BackgroundAccumulating evidence links COVID‐19 incidence and outcomes with vitamin D status. We investigated if an interaction existed between vitamin D levels and social deprivation in those with and without COVID‐19 infection.MethodsUpper or lower respiratory tract samples from 104 patients were tested for SARS‐CoV‐2 RNA in accordance with Public Health England criteria (January‐May 2020) using RT‐PCR. The latest serum total 25‐hydroxyvitamin D(25‐OHD) levels, quantified by LC‐MS/MS, was obtained for each patient (September 2019‐April 2020). Index of Multiple Deprivation (IMD) was generated for each patient. Univariate and logistic regression analyses examined associations between age, gender, 25‐OHD, IMD score and SARS‐CoV‐2 result in the total cohort and subgroups.ResultsIn the total cohort, a positive SARS‐CoV‐2 test was significantly associated with lower 25‐OHD levels and higher IMD. A positive test was associated with higher IMD in the male subgroup and with lower 25‐OHD levels in those aged >72 years. Low 25‐OHD and IMD quintile 5 were separately associated with positive COVID‐19 outcome in the cohort. Patients in IMD quintile 5 with vitamin D levels ≤ 34.4 nmol/L were most likely to have a positive COVID‐19 outcome, even more so if aged >72 years (OR: 19.07, 95%CI: 1.71‐212.25; P = .016).ConclusionsIn this cohort, combined low vitamin D levels and higher social deprivation were most associated with COVID‐19 infection. In older age, this combination was even more significant. Our data support the recommendations for normalising vitamin D levels in those with deficient / insufficient levels and in groups at high risk for deficiency.

Test, trace, isolate: evidence for declining SARS-CoV-2 PCR sensitivity in a clinical cohort

Real-time reverse transcription-polymerase chain reaction (RT-PCR) on upper respiratory tract (URT) samples is the primary method to diagnose SARS-CoV-2 infections and guide public health measures, with a supportive role for serology. We reinforce previous findings on limited sensitivity of PCR testing, and solidify this fact by statistically utilizing a firm basis of multiple tests per individual. We integrate stratifications with respect to several patient characteristics such as severity of disease and time since onset of symptoms. Bayesian statistical modelling was used to retrospectively determine the sensitivity of RT-PCR using SARS-CoV-2 serology in 644 COVID-19-suspected patients with varying degrees of disease severity and duration. The sensitivity of RT-PCR ranged between 80% − 95%; increasing with disease severity, it decreased rapidly over time in mild COVID-19 cases. Negative URT RT-PCR results should be interpreted in the context of clinical characteristics, especially with regard to containment of viral transmission based on ‘test, trace and isolate’. Keywords: SARS-CoV-2, RT-PCR, serology, sensitivity, public health

Real-world SARS CoV-2 testing in Northern England during the first wave of the COVID-19 pandemic

ObjectivesSARS-CoV-2 emerged in South Asia in 2019 and has resulted in a global pandemic. Public Health England (PHE) Manchester rapidly escalated testing for SARS-CoV-2 in the highest COVID-19 incidence location in England. The results of the PHE Manchester SARS-CoV-2 surveillance during the first wave are presented. MethodsRetrospective data were collected for patients fitting the PHE SARS-CoV-2 case definition from 11th February to 31st August 2020. Respiratory tract, tissue, faecal, fluid and cerebrospinal (CSF) samples were tested for SARS-CoV-2 by a semi-quantitative real-time reverse-transcription PCR. ResultsOf the 204,083 tests for SARS-CoV-2, 18,011 were positive demonstrating a positivity of 8.90%. Highest positivity was in nasal swabs (20.99%) followed by broncheo-alveolar lavage samples (12.50%). None of the faecal, fluid or CSF samples received were positive for SARS-CoV-2. ConclusionsThere was a high incidence of SARS-CoV-2 patients in the North-West of England during the first UK wave of the Covid-19 pandemic. Highest positivity rate was in nasal specimens suggesting this is the optimum sample type within this dataset for detecting SARS-CoV-2. Further studies are warranted to assess the utility of testing faecal, fluid and CSF samples. Rapid escalation of testing via multiple platforms was required to ensure prompt diagnosis and isolate infected cases to reduce transmission of the virus.

Analysis of the Clinical and Epidemiological Meaning of Screening Test for SARS-CoV-2: Considerations in the Chronic Kidney Disease Patients during the COVID-19 Pandemic

The COronaVIrus Disease 19 (COVID-19) pandemic is an emerging reality in nephrology. In a continuously changing scenario, we need to assess our patients’ additional risk in terms of attending hemodialysis treatments, follow-up peritoneal dialysis, and kidney transplant visits. The prevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-20 infection in the general population plays a pivotal role in estimating the additional COVID-19 risk in chronic kidney disease (CKD) patients. Unfortunately, local prevalence is often obscure, and when we have an estimation, we neglect the number of asymptomatic subjects in the same area and, consequently, the risk of infection in CKD patients. Furthermore, we still have the problem of managing COVID-19 diagnosis and the test’s accuracy. Currently, the gold standard for SARS-CoV-2 detection is a real-time reverse transcription-polymerase chain reaction (rRT-PCR) on respiratory tract samples. rRT-PCR presents some vulnerability related to pre-analytic and analytic problems and could impact strongly on its diagnostic accuracy. Specifically, the operative proceedings to obtain the samples and the different types of diagnostic assay could affect the results of the test. In this scenario, knowing the local prevalence and the local screening test accuracy helps the clinician to perform preventive measures to limit the diffusion of COVID-19 in the CKD population.

The Unyvero Hospital-Acquired pneumonia panel for diagnosis of secondary bacterial pneumonia in COVID-19 patients

The study was undertaken to evaluate the performance of Unyvero Hospitalized Pneumonia (HPN) panel application, a multiplex PCR-based method for the detection of bacterial pathogens from lower respiratory tract (LRT) samples, obtained from COVID-19 patients with suspected secondary hospital-acquired pneumonia. Residual LRT samples obtained from critically ill COVID-19 patients with predetermined microbiological culture results were tested using the Unyvero HPN Application. Performance evaluation of the HPN Application was carried out using the standard-of-care (SoC) microbiological culture findings as the reference method. Eighty-three LRT samples were used in the evaluation. The HPN Application had a full concordance with SoC findings in 59/83 (71%) samples. The new method detected additional bacterial species in 21 (25%) and failed at detecting a bacterial species present in lower respiratory culture in 3 (3.6%) samples. Overall the sensitivity, specificity, positive, and negative predictive values of the HPN Application were 95.1% (95%CI 96.5–98.3%), 98.3% (95% CI 97.5–98.9%), 71.6% (95% CI 61.0–80.3%), and 99.8% (95% CI 99.3–99.9%), respectively. In conclusion, the HPN Application demonstrated higher diagnostic yield in comparison with the culture and generated results within 5 h.

Validation of the loop-mediated isothermal amplification method for rapid and sensitive detection of Ureaplasma species in respiratory tracts of preterm infants.

IntroductionA simple and rapid diagnosis of Ureaplasma spp. is required for the choice of the appropriate antibiotic. However, an ideal detection method has not been available. This study examines the efficacy of the loop-mediated isothermal amplification (LAMP) assay, which provides rapid and sensitive results, to detect Ureaplasma spp. in respiratory tract samples of preterm infants.MethodsThe study included preterm infants born before 32 weeks of gestation admitted Kagoshima City Hospital from June 2018 to March 2020. Nasopharyngeal swabs and/or tracheal aspirates were obtained in the first seven postnatal days. One hundred sixty-seven nasopharyngeal swabs and 101 tracheal aspirates were analyzed by LAMP, culture, and quantitative real-time polymerase chain reaction.ResultsAll 167 infants had a median (range) gestational age of 28.7 weeks (22.3–30.9) and birthweight 1030g (322–1828). One hundred sixty-seven nasopharyngeal swabs and 101 tracheal aspirates were obtained. In the results of nasopharyngeal swabs, the sensitivity and specificity of LAMP were 73.9% (17/23) and 97.2% (140/144), whereas those of quantitative real-time polymerase chain reaction were 73.9% (17/23) and 95.8% (138/144), compared to culture. In the results of tracheal aspirates, the sensitivity and specificity of LAMP were 89.5% (17/19) and 92.7% (76/82), whereas those of quantitative real-time polymerase chain reaction were 89.5% (17/19) and 93.9% (77/82), compared to culture.ConclusionsThe LAMP assay showed similar sensitivity and specificity with quantitative real-time polymerase chain reaction in the respiratory tracts of preterm infants including extremely preterm infants during the immediate postnatal period. Therefore, the LAMP is a practical alternative for the early detection so that appropriate antibiotics can be administered for preventing BPD.