Comparison of nasopharyngeal nylon flocked swabs with universal transport medium and rayon- bud swabs with a sponge reservoir of viral transport medium in the diagnosis of paediatric influenza

This study compared a kit containing a nasopharyngeal nylon flocked swab and a tube with a liquid universal transport medium (UTM) with a kit containing a plastic-shafted rayon-budded swab with a sponge reservoir of viral transport medium for the molecular detection of influenza viruses in children. Respiratory samples were collected from 314 children aged ,5 years with influenza-like illness (186 males; mean age 2.32±2.27 years) using both swabs in a randomized sequence for each patient. The flocked swabs permitted the detection of 28 influenza A (8.9 %) and 45 influenza B (14.3 %) cases, and the rayon-bud swabs 26 influenza A (8.3 %) and 43 influenza B (13.7 %) cases, with detection rates of 23.2 and 22.0 %, respectively, and similar cycle threshold values. Paediatricians and laboratory staff were significantly more satisfied with both the simplicity (P ,0.0001) and rapidity (P ,0.0001) of the nasopharyngeal flocked swabs with UTM. These findings show that the flocked swabs with UTM and the rayon-bud swabs with a sponge transport medium are similarly efficient in preserving influenza virus nucleic acid, but that the kit containing a flocked swab with a UTM allows easier and more rapid collection and processing of specimens. INTRODUCTION Respiratory infections are the most common diseases of infants and children Antigen detection tests and PCR-based methods are both currently used to detect viruses in respiratory secretions There are various kits containing a nasopharyngeal swab and a tube with transport medium on the market, but only a few studies, mainly of adults, have compared their efficiency in collecting respiratory cells and preserving influenza virus nucleic acid Sample collection. Two samples were collected from each patient and transported by means of two kits: one containing a flexible nasopharyngeal nylon flocked swab and a mini-tube with 1 ml liquid universal transport medium (UTM; Copan Italia), and the other a rayon-budded swab with a tube containing a sponge pre-impregnated with transport medium (Virocult; Medical Wire & Equipment). Using the swabs in a randomized sequence, two nasopharyngeal samples were collected from each child (one from each nostril) by trained paediatricians (L. C., L. G. and S. B.). The distance between the patient's nares and ear lobe was measured to estimate the length of insertion, after which the swabs were gently inserted towards the pharynx until resistance was felt and then rotated three times to obtain epithelial cells. They were then withdrawn and put into the tube containing the specific transport medium. All of the specimens were kept cool and delivered to the laboratory within 3 h of collection. Sample processing. In the laboratory, each swab was processed in triplicate by three researchers (C. G. M., C. D. and A. V.) as indicated by the manufacturers: 190 ml of the liquid transport medium for the flocked swabs was used directly, whereas the rayon-budded swabs were placed in a tube containing 1 ml liquid lysis buffer (the same amount as that contained in the mini-UTM), the tube was vortexed and incubated for 10 min at room temperature, and 190 ml of the solution was used for extraction. PCR. Viral RNA was extracted from all of the samples by means of a NucliSENS EasyMAG automated extraction system (bioMeriéux), using phocine distemper virus (PDV) as an extraction/PCR inhibition control as described previously (Bosis et al., 2005; Staff satisfaction. Trained paediatricians and members of the laboratory staff were asked to record their satisfaction with the simplicity and rapidity using the swabs after the enrolment of each patient or the completion of the analysis of each pair of swabs by completing a 5-point scale (from 5 'very satisfied' to 1 'very dissatisfied'). Statistical analysis. The data relating to the paired specimens collected from 314 children (186 males, 59.2 %), with a mean age of 2.32±2.27 years, were compared using SAS version 9.1 software (SAS Institute). Continuous variables were analysed using Wilcoxon's signed rank test or rank sum test as appropriate, and the categorical variables by means of contingency tables and a x 2 or Fisher's test. RESULTS AND DISCUSSION Satisfaction was based on a 5-point scale from 5 'very satisfied' to 1 'very dissatisfied'. .20 for influenza B virus. However, the paediatricians and laboratory staff were significantly more satisfied with both the simplicity (P ,0.0001) and the rapidity (P ,0.0001) of the nasopharyngeal flocked swabs with UTM. Our study showed that the flocked swabs with UTM and the rayon-budded swabs with transport medium preimpregnated sponge were similarly efficient in preserving influenza virus nucleic acid, but that the former were considered better in terms of the simplicity and rapidity of collection and laboratory testing. Systematic evaluation of the aetiology of paediatric respiratory infections is increasingly being considered an important means of preventing their spread and rationalizing therapy Our main finding was that the paediatricians preferred the flocked swabs because they were more flexible and made it easier and quicker to collect the samples. In addition, the laboratory staff found that the kit containing a flocked swab and liquid transport medium was advantageous insofar as it allowed RNA extraction and PCR to be performed directly on the liquid without the need to add further buffer, whereas the kit containing a transport medium pre-impregnated sponge required an additional step that made the procedure more complicated, timeconsuming and at risk of contamination. One limitation of this study is represented by the fact that the interpretation of the results on simplicity and rapidity of collection and laboratory testing may be devalued by repeated scoring and clustering by the same staff members. This means that further studies that involve several swab collectors and laboratory researchers are required to confirm our results. Moreover, our aim was to compare the efficiency of the two kits in detecting influenza virus nucleic acid, but further studies are required to evaluate the sensitivity of the two transport systems with serial dilutions of positive samples of influenza A and B viruses. Finally, a complete comparison of the sensitivity and specificity of the two kits should also include detection of other respiratory viruses that are commonly found in respiratory samples (e.g. respiratory syncytial virus, adenovirus, rhinovirus), and future research should address this aim. In conclusion, both the flocked swabs with UTM and the rayon-bud swabs with a sponge reservoir of viral transport medium allow adequate collection, transport and preservation of nasal secretions for influenza detection. However, the kit containing a flocked swab with a liquid transport medium facilitated rapid specimen collection and processing. These factors should be considered together with local costs when choosing a product to use in clinical practice. ACKNOWLEDGEMENT

Impact on respiratory tract infections of heptavalent pneumococcal conjugate vaccine administered at 3, 5 and 11 months of age

Abstract Background Medical and public health importance of pneumococcal infections justifies the implementation of measures capable of reducing their incidence and severity, and explains why the recently marketed heptavalent pneumococcal conjugate vaccine (PCV-7) has been widely studied by pediatricians. This study was designed to evaluate the impact of PCV-7 administered at 3, 5 and 11 months of age on respiratory tract infections in very young children. Methods A total of 1,571 healthy infants (910 males) aged 75–105 days (median 82 days) were enrolled in this prospective cohort trial to receive a hexavalent vaccine (DTaP/IPV/HBV/Hib) and PCV-7 (n = 819) or the hexavalent vaccine alone (n = 752) at 3, 5 and 11 months of age. Morbidity was recorded for the 24 months following the second dose by monthly telephone interviews conducted by investigators blinded to the study treatment assignment using standardised questionnaires. During these interviews, the caregivers and the children's pediatricians were questioned about illnesses and the use of antibiotics since the previous telephone call. All of the data were analysed using SAS Windows v.12. Results Among the 1,555 subjects (98.9%) who completed the study, analysis of the data by the periods of follow-up demonstrated that radiologically confirmed community-acquired pneumonia (CAP) was significantly less frequent in the PCV-7 group during the follow-up as a whole and during the last period of follow-up. Moreover, there were statistically significant between-group differences in the incidence of acute otitis media (AOM) in each half-year period of follow-up except the first, with significantly lower number of episodes in children receiving PCV-7 than in controls. Furthermore, the antibiotic prescription data showed that the probability of receiving an antibiotic course was significantly lower in the PCV-7 group than in the control group. Conclusion Our findings show the effectiveness of the simplified PCV-7 schedule (three doses administered at 3, 5 and 11–12 months of age) in the prevention of CAP and AOM, diseases in which Streptococcus pneumoniae plays a major etiological role. A further benefit is that the use of PCV-7 reduces the number of antibiotic prescriptions. All of these advantages may also be important from an economic point of view.</p