Comparison of the AllplexTM Respiratory Panel Assays and the automated Fast Track Diagnostics Respiratory pathogens 21 assay for the diagnosis of pediatric respiratory viral infections.

Acute respiratory tract infections frequently occur in children and represent one of the leading causes of morbidity and mortality worldwide. Quick and accurate pathogen detection can lead to a more appropriate use of antimicrobial treatment as well as timely implementation of isolation precautions. In the last decade, several commercial assays have been developed for the simultaneous diagnosis of respiratory pathogens, which substantially vary in formulation and performance characteristics. The aim of this study was to compare the performance of the "AllplexTM Respiratory Panel Assays" (Seegene) with that of the automated "Fast Track Diagnostics Respiratory pathogens 21" assay (Siemens) for the diagnosis of pediatric respiratory viral infections. One hundred forty-five nasopharyngeal wash samples, collected at the Bambino Gesù Pediatric Hospital in Rome during the fall-winter 2017-2018 season, were processed and analyzed with both workflows. Our results suggest a high concordance between the two methods for positive and negative samples. Sensitivity and specificity were calculated with both tests as a reference method. For the AllplexTM Respiratory Panel Assays, they were 98% and 100%, respectively, and for the Fast Track Diagnostics Respiratory pathogens 21 assay, they were both 100%. This comparative study allowed us to highlight the characteristics of the two assays to evaluate the best solution, on the basis of diagnostic routine and laboratory workflows, keeping in mind local epidemiology.

Advancement in the routine identification of anaerobic bacteria by MALDI-TOF mass spectrometry.

We evaluated matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) Biotyper as a tool for the identification of anaerobic bacteria compared with 500 base-pair (bp) 16S ribosomal ribonucleic acid (rRNA) gene sequencing analysis, which is considered to be the "gold standard" method. A total of 484 anaerobic bacteria were retrieved from the clinical specimens of 318 pediatric patients. Molecular identification resulted in 18 genera and 51 species. The most prevalent genus was Clostridium (76.85 %), with 70 % C. difficile isolates. The concordance and sensitivity determined by MALDI-TOF MS for C. difficile, the most prevalent species isolated, was 94.08 %, whereas the specificity was 100 %. For the other anaerobes, the sensitivity and specificity were 94.07 % and 81.82 %, respectively, with a concordance of 93.15 %. Low performance was observed for Propionibacterium acnes and Fusobacterium nucleatum, for which a dedicated pretreatment procedure should likely be set up. MALDI-TOF MS was shown to be a valid alternative for the fast and reliable identification of the most clinically relevant anaerobic bacteria; moreover, it is less time-consuming, the cost for reagents is minimized, and it does not require dedicated personnel.

Prolonged in-hospital exposure to an infant with active pulmonary tuberculosis.

Active pulmonary tuberculosis was diagnosed in a 4-month-old infant 16 days after hospitalization; 186 exposed individuals were traced and one conversion detected. Although the risk of tuberculosis transmission in paediatric hospitals is low, paediatricians in low-incidence countries should maintain a high level of alert for timely identification of cases.

Suspected transmission of tuberculosis in a maternity ward from a smear-positive nurse: preliminary results of clinical evaluations and testing of neonates potentially exposed, Rome, Italy, 1 January to 28 July 2011.

We report preventive measures adopted after tuberculosis(TB) transmission from a nurse to a newborn assessed in late July 2011. All exposed neonates born between January and July 2011 were clinically evaluated and tested by QuantiFERON TB gold in-tube; newborns testing positive were referred for prophylaxis.Of 1,340 newborns, 118 (9%) tested positive and no other active cases of TB were found. Active surveillance for TB will be continued over the next three years for all those exposed.

Comparative analysis of 2 commercial molecular tests for the detection of gastroenteric viruses on stool samples.

OBJECTIVE: Our purpose was to compare the performance of 2 recently introduced molecular tests for the identification of gastrointestinal viral infections. METHODS: One hundred fecal samples from pediatric patients were analyzed using 2 workflows, each including nucleic acids extraction and multiplex Real-Time PCR: Allplex™ GI-Virus Assay and FTD Viral gastroenteritis. The agreement was evaluated calculating Cohen's kappa and applying McNemar's test. RESULTS AND CONCLUSION: Allplex and FTD assays showed 100% overall agreement for Norovirus GI/GII and Sapovirus (κ: 1.00), and 99% for Astrovirus (κ: 0.66). A lower agreement was detected for Adenovirus (89%; κ: 0.72) and Rotavirus (91%, k: 0.53), owing to samples resulted positive only with FTD test. The discrepancies were attributed to a different efficiency of extraction/amplification and to the different Adenovirus serotype specificity of the tests since Allplex detects only AdVF40 and AdVF41. FTD test should be used when non enteric adenovirus could have a clinical significance.

Genotyping of different Pseudomonas aeruginosa morphotypes arising from the lower respiratory tract of a patient taken to an Intensive Care Unit.

Pseudomonas aeruginosa is an opportunistic pathogen and an ubiquitous environmental bacterium. Fifty-seven days after hospitalization, we isolated three distinct P. aeruginosa morphotypes (smooth, rough and mucoid) from the lower respiratory tract of a patient admitted to a Cardiology Intensive Care Unit (ICU). Moreover, a group of nine colony variants, arising from the three P. aeruginosa isolates growing in laboratory growth media, were also isolated. The resulting 12 isolates were characterised for antibiotic resistance profile and subjected to genotypic analysis by fluorescent-Amplified Fragment Length Polymorphism (f-AFLP) and automated repetitive extragenic palindromic-PCR (rep-PCR) fingerprinting. The three smooth, rough and mucoid morphotypes presented different antibiotic resistance profiles and genotyping analysis showed that they belonged to distinct clones, indicating that at day 57 after the admission the patient was simultaneously colonized by three distinct P. aeruginosa isolates. On the other hand, the nine colony variants presented heterogeneous antibiotic resistance profiles and clustered together with the three parental isolates. The understanding of the link between genotype plasticity and antibiotic resistance may contribute to improving our knowledge of this life-threatening pathogen.