Standard method for detecting upper respiratory carriage of Streptococcus pneumoniae: Updated recommendations from the World Health Organization Pneumococcal Carriage Working Group

Abstract

In 2003 the World Health Organization (WHO) convened a working group and published a set of standard methods for studies measuring nasopharyngeal carriage of Streptococcus pneumoniae (the pneumococcus). The working group recently reconvened under the auspices of the WHO and updated the consensus standard methods. These methods describe the collection, transport and storage of nasopharyngeal samples, as well as provide recommendations for the identification and serotyping of pneumococci using culture and non-culture based approaches. We outline the consensus position of the working group, the evidence supporting this position, areas worthy of future research, and the epidemiological role of carriage studies. Adherence to these methods will reduce variability in the conduct of pneumococcal carriage studies undertaken in the context of pneumococcal vaccine trials, implementation studies, and epidemiology studies more generally so variability in methodology does not confound the interpretation of study findings.

Molecular mechanisms and epidemiology of resistance in Streptococcus pneumoniae in the Middle East region

“…The lytA gene is considered to be a specific molecular target for pneumococcus identification, where its restriction by BsaI provides in addition specific signatures for reliable diagnosis of S. pneumoniae infections, especially those caused by non-typeable strains [7]. Moreover, real-time PCR targeting lytA was recommended as a rapid and reliable non-culture assay to complement the gold standard culture technique for S. pneumoniae detection [8]. Nevertheless, a new study showed that misidentification of S. pneumoniae can occur [9].…”

Capsular Serotyping of <em>Streptococcus pneumoniae</em> Using the Quellung Reaction

“…The method presented here is viewed without oil-immersion and under 400X magnification 15,17 . This method is quick, simple and relatively easy to read 23 .…”

“…However, this is minimized in the above protocol due to the small amount of antiserum used for each reaction. Several other methods have been described for serotyping pneumococci 23,24 . However, Quellung remains the gold standard and the development of new methods requires standardization against the Quellung reaction 23 .…”

“…Several other methods have been described for serotyping pneumococci 23,24 . However, Quellung remains the gold standard and the development of new methods requires standardization against the Quellung reaction 23 . Using appropriate antisera, the Quellung reaction can also be utilized to identify and type other capsule producing bacteria 25 .…”

Cord blood Streptococcus pneumoniae-specific cellular immune responses predict early pneumococcal carriage in high-risk infants in Papua New Guinea

“…Standardized methodologies were used for collection, transportation and storage of the NPS and subsequent culturing, identification and isolation of S. pneumoniae 31, 32. Briefly, NPS were stored in 1 ml of skimmed milk–glucose–glycerol broth (SMGGB) at −70°C until further processing at the PNG Institute of Medical Research.…”