Realtime PCR Is More Sensitive than Multiplex PCR for Diagnosis and Serotyping in Children with Culture Negative Pneumococcal Invasive Disease

Background: Pneumococcal serotyping is usually performed by Quellung reaction, considered the gold standard test. However the method cannot be used on culture-negative samples. Molecular methods can be a useful alternative. The aim of the study was to evaluate the use of Multiplex-sequential-PCR (MS-PCR) or Realtime-PCR on blood samples for diagnosis and serotyping of invasive pneumococcal disease (IPD) in a pediatric clinical setting. Methodology/Principal Findings: Sensitivity and specificity of MS-PCR and Realtime-PCR have been evaluated both on 46 well characterized pneumococcal isolates and on 67 clinical samples from children with culture-negative IPD. No difference in sensitivity and specificity between MS-PCR and Realtime PCR was found when the methods were used on isolates: both methods could type 100 % isolates and the results were always consistent with culture-based methods. On the contrary, when used on clinical samples 43/67 (64.2%) were typeable by MS-PCR and 61/67 (91.0%) by Realtime-PCR (p = 0.0004,K Cohen 0.3, McNemar’s p,0.001). Non-typeability by MS-PCR was associated in 18/20 cases (90.0%) with low bacterial load. The difference between the two methods was present both when they were used on normally sterile fluids (respectively 31/ 33 (93.9%) typeable samples for Realtime-PCR and 24/33 (72.7%) for MS-PCR, p = 0.047, 95%CL 0.03–0.98; K Cohen 0.3; McNemar’s p = 0.0016) and when they were used on nasopharyngeal swabs (respectively 30/34 (88.2%) typeable samples for Realtime-PCR and 19/34 (55.9%) for MS-PCR, p = 0.007, 95%CL 0.04–0.66); the presence of multiple pneumococca

Pneumococcal DNA is not detectable in the blood of healthy carrier children by real-time PCR targeting the lytA gene

The diagnosis of invasive pneumococcal disease (IPD) is currently based on culture methods, which lack sensitivity, especially after antibiotic therapy. Molecular methods have improved sensitivity and do not require viable bacteria; however, their use is complicated by reports of low specificity with some assays. The present study investigated the specificity of a real-time PCR targeting lytA for the detection of IPD. A group of 147 healthy children, aged 6 months to 16 years (mean 6.4 years, median 4.9 years, interquartile range 6.4 years), who were in hospital for routine examinations, were tested for pneumococcal carrier status and for the presence of detectable pneumococcal DNA in their blood by real-time PCR targeting the pneumococcal lytA gene. In addition, 35 culture-positive biological samples were analysed. Urine was examined for the presence of pneumococcal DNA and C-polysaccharide antigen. Carriage was detected in 77 of the 147 subjects (52.4 %); however, regardless of carrier status, none of the subjects had a positive result from blood. Analysis of the culture-positive biological samples yielded positive results in 100 % (15/15) of cerebrospinal fluid samples and 95 % (19/20) of blood samples. All urine samples from healthy carriers were negative for DNA, whilst antigenuria was detected in 44/77 carriers (57.1 %). In conclusion, real-time PCR is both sensitive and specific and can be a useful tool in the routine diagnosis of IPD. Its sensitivity, which surpasses that of other methods for this purpose, does not come at the cost of reduced specificity

Sensitivity of three commercial tests for SARS-CoV-2 serology in children: an Italian multicentre prospective study

US Food and Drug Administration has issued Emergency Use Authorizations for hundreds of serological assays to support Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) diagnosis. The aim of this study is to evaluate, for the first time in children, the performance of three widely utilized SARS-CoV-2 serology commercial assays, Diesse Diagnostics (IgG, IgA, IgM) and Roche Diagnostics, both Roche Nucleocapsid (N) IgG and Roche Spike (S) IgG assays. Methods: Sensitivity and 95% confidence intervals (CIs) were estimated for each of the three different serological tests and mixed and direct comparison were performed. Univariate and multivariate Poisson regression models were fitted to calculate incidence rate ratios and 95% CIs as estimate of the effects of age, gender, time on the serology title. A p-value < 0.05 indicated statistical significance. Results: Overall, 149 children were enrolled in the study. A low sensitivity was found for Diesse IgA, IgM and IgG. Compare to Diesse, Roche S had a higher sensitivity at 15-28 days from infection (0.94, 95%CI: 0.73-1.0) and Roche N at 28-84 days (0.78, 95%CI: 0.58-0.91). When a direct comparison of IgG tests sensitivity was feasible for patients with pairwise information, Roche S and Roche N showed a statistically significant higher sensitivity compared to Diesse in all the study periods, whereas there was no difference between the two Roche tests. Conclusion: Roche S and Roche N serology tests seem to better perform in children. Large prospective studies are needed to better define the characteristics of those tests

Molecular detection methods and serotyping performed directly on clinical samples improve diagnostic sensitivity and reveal increased incidence of invasive disease by Streptococcus pneumoniae in Italian children

The aims of this study were to evaluate the incidence of invasive pneumococcal disease (IPD) in Italian children and perform serotyping by PCR-based assays directly on clinical samples. A 1-year paediatric (0–14 years) population-based surveillance study was designed to evaluate the incidence of IPD in the province of Florence, Italy, by cultural and molecular methods. Among 92 children (80 with pneumonia, 8 with meningitis/sepsis, 4 with arthritis), 4 cases of IPD were diagnosed both by culture and real-time PCR and 18 cases exclusively by molecular methods. The sensitivity of molecular methods was significantly higher than that of cultural methods (Cohen’s κ 0.41; McNemar P=0.000008). The incidence of IPD in children below 2 years of age was 11.5/100 000 and 51.8/100 000 by cultural and molecular methods, respectively. Pneumococcal serotyping by multiplex sequential PCR was obtained in 19/22 samples. Real-time PCR and multiplex sequential PCR can be used directly on biological samples, improving the ability to diagnose IPD. The incidence of IPD appears 5–10 times higher by PCR than by cultural methods

Second-line biologic therapy optimization in rheumatoid arthritis, psoriatic arthritis, and ankylosing spondylitis

Objective The Italian board for the TAilored BIOlogic therapy (ITABIO) reviewed the most consistent literature to indicate the best strategy for the second-line biologic choice in patients with rheumatoid arthritis (RA), spondyloarthritis (SpA), and psoriatic arthritis (PsA). Methods Systematic review of the literature to identify English-language articles on efficacy of second-line biologic choice in RA, PsA, and ankylosing spondylitis (AS). Data were extracted from available randomized, controlled trials, national biologic registries, national healthcare databases, post-marketing surveys, and open-label observational studies. Results Some previously stated variables, including the patients׳ preference, the indication for anti-tumor necrosis factor (TNF) monotherapy in potential childbearing women, and the intravenous route with dose titration in obese subjects resulted valid for all the three rheumatic conditions. In RA, golimumab as second-line biologic has the highest level of evidence in anti-TNF failure. The switching strategy is preferable for responder patients who experience an adverse event, whereas serious or class-specific side effects should be managed by the choice of a differently targeted drug. Secondary inadequate response to etanercept (ETN) should be treated with a biologic agent other than anti-TNF. After two or more anti-TNF failures, the swapping to a different mode of action is recommended. Among non-anti-TNF targeted biologics, to date rituximab (RTX) and tocilizumab (TCZ) have the strongest evidence of efficacy in the treatment of anti-TNF failures. In PsA and AS patients failing the first anti-TNF, the switch strategy to a second is advisable, taking in account the evidence of adalimumab efficacy in patients with uveitis. The severity of psoriasis, of articular involvement, and the predominance of enthesitis and/or dactylitis may drive the choice toward ustekinumab or secukinumab in PsA, and the latter in AS. Conclusion Taking in account the paucity of controlled trials, second-line biologic therapy may be reasonably optimized in patients with RA, SpA, and PsA

Number of typeable or non-typeable samples obtained from patients with culture-negative invasive pneumococcal infections as evidenced by Multiplex Sequential PCR or Realtime-PCR (sensitivity of Realtime vs Multiplex Sequential PCR p = 0.0004; 95%CL 1.98–17.05).

<p>Number of typeable or non-typeable samples obtained from patients with culture-negative invasive pneumococcal infections as evidenced by Multiplex Sequential PCR or Realtime-PCR (sensitivity of Realtime vs Multiplex Sequential PCR p = 0.0004; 95%CL 1.98–17.05).</p

Presence of single or multiple pneumococcal serogroups/serotypes in nasopharyngeal swabs as evidenced by Multiplex Sequential PCR or Realtime-PCR (frequency of multiple serotypes/serogroup evaluated with Realtime PCR vs Multiple Sequential PCR p = 0.003; 95%CL = 1.87–39.97).

<p>Presence of single or multiple pneumococcal serogroups/serotypes in nasopharyngeal swabs as evidenced by Multiplex Sequential PCR or Realtime-PCR (frequency of multiple serotypes/serogroup evaluated with Realtime PCR vs Multiple Sequential PCR p = 0.003; 95%CL = 1.87–39.97).</p