Capsular Serotyping of &lt;em&gt;Streptococcus pneumoniae&lt;/em&gt; Using the Quellung Reaction

Habib, Maha; Porter, Barbara D.; Satzke, Catherine

doi:10.3791/51208

Cited by 61 publications

(52 citation statements)

References 21 publications

(22 reference statements)

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“…These are most likely negative reactions. In such cases, we recommend retesting and/or further investigation using another serotyping method (for example the Quellung reaction 17 ). …”

Section: Representative Resultsmentioning

confidence: 99%

“…Serotyping a pneumococcal isolate by latex agglutination takes approximately 10 min, and up to four latex reagents can be tested in parallel on the one slide. Furthermore, if the prevalence of serotypes is known for the relevant epidemiological setting, testing can be performed in rounds starting with the pools containing the most common serotypes similarly to the Quellung test 17 . This approach minimizes the number of tests needed to determine the serotype.…”

Section: Discussionmentioning

confidence: 99%

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Capsular Serotyping of <em>Streptococcus pneumoniae</em> by Latex Agglutination

Porter

Ortika

Satzke

2014

JoVE

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Latex agglutination reagents are widely used in microbial diagnosis, identification and serotyping. Streptococcus pneumoniae (the pneumococcus) is a major cause of morbidity and mortality world-wide. Current vaccines target the pneumococcal capsule, and there are over 90 capsular serotypes. Serotyping pneumococcal isolates is therefore important for assessing the impact of vaccination programs and for epidemiological purposes. The World Health Organization has recommended latex agglutination as an alternative method to the 'gold standard' Quellung test for serotyping pneumococci. Latex agglutination is a relatively simple, quick and inexpensive method; and is therefore suitable for resource-poor settings as well as laboratories with high-volume workloads. Latex agglutination reagents can be prepared in-house utilizing commercially-sourced antibodies that are passively attached to latex particles. This manuscript describes a method of production and quality control of latex agglutination reagents, and details a sequential testing approach which is time-and cost-effective.This method of production and quality control may also be suitable for other testing purposes.

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“…These are most likely negative reactions. In such cases, we recommend retesting and/or further investigation using another serotyping method (for example the Quellung reaction 17 ). …”

Section: Representative Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Capsular Serotyping of <em>Streptococcus pneumoniae</em> by Latex Agglutination

Porter

Ortika

Satzke

2014

JoVE

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“…Equivocal reactions were confirmed using the Quellung reaction with antisera from SSI [25]. Isolates that were non-typeable were tested for the presence of the lytA gene by real-time PCR [26].…”

Section: Methodsmentioning

confidence: 99%

Long-term impact of pneumococcal polysaccharide vaccination on nasopharyngeal carriage in children previously vaccinated with various pneumococcal conjugate vaccine regimes

Boelsen

Dunne

Lamb

et al. 2015

Vaccine

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Previously, the Fiji Pneumococcal Project (FiPP) evaluated reduced dose immunization schedules that incorporated pneumococcal protein conjugate and/or polysaccharide vaccine (PCV7 and 23vPPV, respectively). Immune hyporesponsiveness was observed in children vaccinated with 23vPPV at 12 months of age compared with children who did not receive 23vPPV. Here we assess the long-term impact of 23vPPV vaccination on nasopharyngeal carriage rates and densities of Streptococcus pneumoniae, Haemophilus influenzae, Staphylococcus aureus and Moraxella catarrhalis. Nasopharyngeal swabs (n=194) were obtained from healthy children who participated in FiPP (now aged 5–7 years). S. pneumoniae were isolated and identified by standard culture-based methods, and serotyped using latex agglutination and the Quellung reaction. Carriage rates and densities of S. pneumoniae, H. influenzae, S. aureus and M. catarrhalis were determined using real-time quantitative PCR. There were no differences in the rate or density of S. pneumoniae, H. influenzae or M. catarrhalis carriage by PCV7 dose or 23vPPV vaccination in the vaccinated participants overall. However, differences were observed between the two main ethnic groups: Fijian children of Indian descent (Indo-Fijian) were less likely to carry S. pneumoniae, H. influenzae and M. catarrhalis, and there was evidence of a higher carriage rate of S. aureus compared with indigenous Fijian (iTaukei) children. Polysaccharide vaccination appeared to have effects that varied between ethnic groups, with 23vPPV vaccination associated with a higher carriage rate of S. aureus in iTaukei children, while there was a lower carriage rate of S. pneumoniae associated with 23vPPV vaccination in Indo-Fijian children. Overall, polysaccharide vaccination had no long-term impact on pneumococcal carriage, but may have impacted on S. aureus carriage and have varying effects in ethnic groups, suggesting current WHO vaccine schedule recommendations against the use of 23vPPV in children under two years of age are appropriate.

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“…It 131 is also inconvenient for serotyping large number of isolates and is rela-132 tively laborious and costly as it requires a supply of pneumococcal 133 antisera. To improve the latter, Habib and colleagues (Habib et al,134 2014) developed an improved Quellung protocol that minimizes the 135 amount of antisera used (Habib et al, 2014) (a video for the protocol 136 is also available at http://www.jove.com/video/51208/). This is done (Christensen et al, 1973;Kronvall, 1973;Lund and 154 Rasmussen, 1966;SSI, 2012).…”

mentioning

confidence: 99%

“…The described agglutination method is a break-through 169 due to its accuracy, rapidity and the significant reduction of antiserum 170 used compared to the Quellung reaction(Porter et al, 2014). blot(Fenoll et al, 1997) and colony blot assays(Bogaert et al, 173 2004) have been suggested as alternatives to the Quellung reaction as 174 faster and less expensive methods for pneumococcal typing.…”

mentioning

confidence: 99%