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Advantages and Benefits of PneumoArray^® 

PneumoArray® provides significant advantages over serotyping methods based on the Quellung test: Objectivity, specificity and reproducibility in the interpretation of results Simplicity of use and high capacity for analysis (up to 12 samples per array) Results are logged and fully traceable Lower cost The advantages of PneumoArray® over PCR-based techniques: Discrimination of serotypes at the level of factor Ease of use and lower processing time

Methods of epidemiological analysis

The most commonly used technique for the epidemiological typing of pneumococcal bacteria is the Quellung reaction. This involves the use of a collection of antisera developed against the 91 capsular serotypes of S. pneumoniae. However this is a complex and laborious process which is both subjective and nonspecific and requires trained laboratory personnel for correct interpretation of the results (Fig. 1). The use of a method requiring such a subjective interpretation for epidemiological purposes remains questionable. Owing to these limitations the use of the Quellung reaction is restricted to national testing centers and other specialized laboratories. Other techniques, such as latex agglutination, ELISA, dot-blot and PCR are only able to identify a limited number of serotypes.

The prevalence of pneumococcal infection should ideally be determined in a standardized, precise and simple, manner. Proteomika has developed PneumoArray^® a highly specific, objective and straightforward test for typing Streptococcus pneumoniae. PneumoArray^® uses the same standard antisera employed in the Quellung reaction but adapted to a microarray format (Fig. 2). The technique makes extremely efficient use of reagents allowing a sample to be typed using only a few nanolitres of each antisera; use of the method requires no specialist training and interpretation of results is objective and direct.

Fig 1. During the quellung reaction swelling of the capsule is observed when a specific antibody recognizes bacterial cells. Results are observed and annotated by microscopic examination by trained laboratory personnel.

Fig. 2. The same antisera collection employed in the Quellung reaction is used in PneumoArray®. Results are given by unequivocal positive spots in the surface of the microarray, therefore misinterpretation is not possible. Reaction patterns are correlated to the correct serotype by using a template. Digitized images can be stored as a laboratory record or for further confirmation, analysis or shared between laboratories.