COMPARISON OF METHODS TO IDENTIFY Neisseria meningitidis IN ASYMPTOMATIC CARRIERS

Abstract

SUMMARY Neisseria meningitidis is a cause of several life-threatening diseases and can be a normal commensal in the upper respiratory tract of healthy carriers. The carrier rate is not well established especially because there is no standard method for the isolation of N. meningitidis. Therefore, the aim of this study was to compare identification methods for the carrier state. Two swabs were collected from 190 volunteers: one was cultured and the other had DNA extracted directly from the sample. The Polymerase Chain Reaction (PCR) was performed to determine species and serogroups and compared the results between the methods. PCR for species determination used two pairs of primers and when there was only one amplicon, it was sequenced. The culture technique was positive in 23 (12.1%) subjects while the direct extraction method was positive in 132 (69.5%), p < 0.001. Among the 135 subjects with positive N. meningitides tests, 88 (65.2%) were serogroup C; 3 (2.2%) serogroup B; 5 (3.7%) were positive for both serogroup B and C, and 39 (28.9%) did not belong to any of the tested serogroups. In this study, PCR from DNA extracted directly from swabs identified more N. meningitidis asymptomatic carriers than the culture technique.

Serogroup-specific meningococcal carriage by age group: a systematic review and meta-analysis

“…Results from studies included in this review suggest that conventional microbiological methods, such as immediate plating for culture, might be less sensitive than PCR analysis of DNA taken directly from the swab or growth in Todd-Hewitt broth in some, but not all, cases 25–29. The difference in sensitivity was most noticeable for age groups with the highest carriage and ‘other’ groups but was sometimes important for disease-associated groups as well.…”

“…These concerns will continue to abound and make future analyses difficult. This is especially true as new techniques, such as direct PCR analysis of pharyngeal swabs as employed in studies by Gilca et al , Rizek et al , Jeppessen et al , and van Ravenhorst et al , increase in popularity 25 27–29. Additional research is needed to determine the most sensitive and effective methods for carriage detection and characterisation.…”

Meningococcal carriage in high-risk settings: A systematic review

“…Fifteen studies that sampled only university students met the inclusion criteria. Six studies were cross-sectional studies (Aliyu and Olayinka, 2017;Bali et al, 2017;Rizek et al, 2016;Rodrigues et al, 2015;Rodriguez et al, 2014;Tryfinopoulou et al, 2016;Takahashi et al, 2016), six were repeat cross-sectional studies with a nested cohort (either intentional or unintentional) (Ala'aldeen et al, 2011;Breakwell et al, 2018;Durey et al, 2012;McNamara et al, 2017b;Oldfield et al, 2017;Soeters et al, 2017), two were cohort studies (Bidmos et al, 2011;Gilca et al, 2013), and one was a randomized controlled trial investigating the impact of vaccination on carriage (Read et al, 2014). The majority of studies were conducted in the region of the Americas (n = 6) or the European region (n = 6), and no study was identified from the Eastern Mediterranean region.…”

Detection of meningococcus, pneumococcus, Haemophilus influenzae, and group A streptococcus DNA in pediatric adenoid bioptats

“…На преимущества метода ПЦР указывают и результаты Rizek и соавт. [25]. Слизь из носоглотки от 190 здоровых людей была исследована на содержание N. meningitidis двумя методами -бактериологическим и ПЦР.…”