Sampling methods to detect carriage of Neisseria meningitidis; literature review

Roberts, Jonathan; Greenwood, Brian; Stuart, James M.

doi:10.1016/j.jinf.2008.12.005

Cited by 37 publications

(25 citation statements)

References 22 publications

(39 reference statements)

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“…Oropharyngeal swabbing combined with either direct plating, as used in this study, or short transportation time of the swab, improves detection of meningococcal carriage [57]. No false negative isolates were identified among the presumed non-meningococcal external quality control samples.…”

Section: Discussionmentioning

confidence: 99%

Prevalence and epidemiology of meningococcal carriage in Southern Ethiopia prior to implementation of MenAfriVac, a conjugate vaccine

et al. 2016

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Background Neisseria meningitidis colonizes humans and transmits mainly by asymptomatic carriage. We sought to determine the prevalence and epidemiology of meningococcal carriage in Ethiopia prior to the introduction of MenAfriVac, a serogroup A meningococcal conjugate vaccine.MethodsA cross-sectional meningococcal carriage study was conducted in Arba Minch, southern Ethiopia. A total of 7479 oropharyngeal samples were collected from 1 to 29 year old volunteers, between March and October, 2014. The swabs were cultured for N. meningitidis and Neisseria lactamica in Ethiopia. N. meningitidis isolates were confirmed and characterized by their serogroup, sequence type (ST) and PorA:FetA profile in Norway.ResultsOverall carriage prevalence was 6.6 %. There was no significant difference in overall carriage between male (6.7 %) and female (6.4 %) participants. Highest carriage prevalence (10.9 %) for females was found in the 15–19 years of age, while prevalence among males was highest (11.3 %) in the 20–24 age group. Non-groupable isolates dominated (76.4 %), followed by serogroups X (14.0 %) and W (5.9 %) isolates. No serogroup A was found. Most non-groupable isolates were ST-192. Serogroup W isolates were assigned to the ST-11 clonal complex, and serogroup X isolates to the ST-181 and ST-41/44 clonal complexes. Overall carriage prevalence of N. lactamica was 28.1 %. Carriage of N. meningitidis and N. lactamica varied depending on age and geographic area, but there was no association between carriage of the two species.ConclusionsEpidemic strains of serogroups W and X were circulating in this area of Ethiopia. As no serogroup A was found among the carriage isolates the immediate impact of mass-vaccination with MenAfriVac on transmission of N. meningitidis in this population is expected to be marginal.

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Section: Discussionmentioning

confidence: 99%

Prevalence and epidemiology of meningococcal carriage in Southern Ethiopia prior to implementation of MenAfriVac, a conjugate vaccine

et al. 2016

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“…A recent literature review by Roberts et al states that meningococcal carriage should be assessed by swabbing the posterior wall of the oropharynx followed by direct plating or storage of the swab in a transport medium for less than 5 h before culturing (32). To our knowledge, however, there are no reports on the use of an STGG transport medium for the storage of meningococcal isolates at Ϫ70°C.…”

Section: Discussionmentioning

confidence: 99%

Genotypic and Phenotypic Characterization of Carriage and Invasive Disease Isolates of Neisseria meningitidis in Finland

et al. 2012

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“…1 In contrast to several other occasionally invasive bacterial pathogens which are commonly found in the human upper respiratory tract, the peak age of colonization with Nm is in adolescence and early adulthood rather than early childhood and the bacterium is more commonly detected in the throat than in the nasopharynx. 1,2 The evident importance of measuring and understanding the normally benign state of Nm carriage became apparent through the recognition that the effectiveness of group C Nm conjugate vaccines and, probably, those against serogroups A, W and Y resides primarily in their ability, when widely used, to prevent acquisition of invasive strains in the population. As a consequence, transmission to vulnerable individuals is reduced, importantly protecting young children, 3 in whom seroresponses to these vaccines are relatively short lived.…”

Section: Introductionmentioning

confidence: 99%

“…Nearly all published studies of Nm carriage have involved the direct plating of pharyngeal swabs onto appropriate media, usually immediately after they have been taken, 2,7 and have reported Nm colonization as a binary endpoint -either present or absent, based on standard culture and identification techniques. We have recently reported wide ranges in density of nasopharyngeal carriage of several bacterial species in pre-school children measured by single gene real time…”

Section: Introductionmentioning

confidence: 99%

Density Distribution of Pharyngeal Carriage of Meningococcus in Healthy Young Adults

Finn

Morales-Aza

Sikora

et al. 2016

Pediatric Infectious Disease Journal

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Background: Improved understanding of Neisseria meningitidis (Nm) carriage biology and better methods for detection and quantification would facilitate studies of potential impact of new vaccines on colonization and transmission in adolescents. Methods:We performed plate cultures on 107 oropharyngeal swabs stored frozen in STGG broth and previously positive for Nm. We compared quantitative (q)PCR detection of Nm in 601 STGG-swabs with culture. Using qPCR (n=87), a log-phase broth culture standard curve and semi-quantitative plate cultures (n=68), we measured density of carriage. We compared qPCR genogrouping of DNA extracts from STGG-swabs and from plate culture lawns (n=110) with purified isolates (n=80).Results: Swab storage resulted in only 10% loss of culture sensitivity. Direct sodC qPCR Nm detection yielded more positives (87/601, 14.5%) than culture (80/601, 13.3%). Most samples (57/110) positive by culture were also positive by qPCR and vice versa, but discrepancies (single positives) were frequent among low density samples. sodC qPCR was positive in 79/80 isolates but in only 65 by ctrA qPCR. Density both by culture and qPCR varied across 4 orders of magnitude with the majority being low (<50 bacteria-gene copies/mL) and a minority being high (>1000). Genogrouping qPCRs yielded more positive results when performed on DNA extracts from lawn cultures. Conclusions:We provide the first description of the distribution of Nm carriage density. This could be important for understanding transmission dynamics and population-level effectiveness of adolescent vaccine programs. Storage of swabs frozen in STGG for batched laboratory analysis facilitates carriage studies and direct sodC qPCR for Nm combined with qPCR genogrouping of lawn culture extracts provides accurate, detailed description of colonization.

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Sampling methods to detect carriage of Neisseria meningitidis; literature review

Cited by 37 publications

References 22 publications

Prevalence and epidemiology of meningococcal carriage in Southern Ethiopia prior to implementation of MenAfriVac, a conjugate vaccine

Prevalence and epidemiology of meningococcal carriage in Southern Ethiopia prior to implementation of MenAfriVac, a conjugate vaccine

Genotypic and Phenotypic Characterization of Carriage and Invasive Disease Isolates of Neisseria meningitidis in Finland

Density Distribution of Pharyngeal Carriage of Meningococcus in Healthy Young Adults

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