This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Verhelst, R. Articles by Vaneechoutte, M. Search for Related Content PubMed PubMed Citation Articles by Verhelst, R. Articles by Vaneechoutte, M.

Comparison of Five Genotypic Techniques for Identification of Optochin-Resistant Pneumococcus-Like Isolates

Department of Chemistry, Microbiology and Immunology, Ghent University Hospital, Gent, Belgium,¹ National Reference Laboratory for Pneumococcus, National Public Health Institute, Oulu, Finland²

Received 31 December 2002/ Returned for modification 3 March 2003/ Accepted 8 May 2003

Three PCR techniques (amplification of the psaA, ply, and lytA genes) and a commercial kit (AccuProbe [GenProbe, San Diego, Calif.], based on hybridization with the 16S rRNA gene), all four of which claimed to be specific for Streptococcus pneumoniae, were used to identify 49 alpha-hemolytic streptococcal isolates suspected of being pneumococci. The definite phenotypic identification of these organisms as S. pneumoniae was difficult when optochin susceptibility and the presence of a capsule were taken as markers. Furthermore, RsaI digestion of the amplified 16S rRNA gene was applied. All 49 strains were optochin resistant. Eleven of these were encapsulated and were identified as pneumococci by all tests. Twenty of the 38 unencapsulated strains were unambiguously identified as nonpneumococci by all tests. The identities of another 18 unencapsulated strains remained inconclusive due to highly variable reactions for all phenotypic and genotypic techniques applied. The AccuProbe test was positive for seven strains for which the results of the other tests were inconclusive. RsaI restriction of the amplified 16S rRNA gene confirmed the AccuProbe result for all strains, while the result of the psaA-specific PCR was in concordance with encapsulation for all strains. The results presented here indicate that identification problems continue to exist for some strains, despite the application of genotypic and phenotypic tests in combination. We found the psaA-specific PCR to be the genotypic technique best suited for the identification of genuine pneumococci and optochin-resistant pneumococci.

This article has been cited by other articles:

• Cortes, P. R., Orio, A. G. A., Regueira, M., Pinas, G. E., Echenique, J. (2008). Characterization of In Vitro-Generated and Clinical Optochin-Resistant Strains of Streptococcus pneumoniae Isolated from Argentina. J. Clin. Microbiol. 46: 1930-1934 [Abstract] [Full Text]  
• Nunes, S., Sa-Leao, R., de Lencastre, H. (2008). Optochin Resistance among Streptococcus pneumoniae Strains Colonizing Healthy Children in Portugal. J. Clin. Microbiol. 46: 321-324 [Abstract] [Full Text]  
• Dias, C. A., Agnes, G., Frazzon, A. P. G., Kruger, F. D., d'Azevedo, P. A., Carvalho, M. d. G. S., Facklam, R. R., Teixeira, L. M. (2007). Diversity of Mutations in the atpC Gene Coding for the c Subunit of F0F1 ATPase in Clinical Isolates of Optochin-Resistant Streptococcus pneumoniae from Brazil. J. Clin. Microbiol. 45: 3065-3067 [Abstract] [Full Text]  
• Ip, M., Chau, S. S. L., Chi, F., Tang, J., Chan, P. K. (2007). Fluoroquinolone Resistance in Atypical Pneumococci and Oral Streptococci: Evidence of Horizontal Gene Transfer of Fluoroquinolone Resistance Determinants from Streptococcus pneumoniae. Antimicrob. Agents Chemother. 51: 2690-2700 [Abstract] [Full Text]  
• Suzuki, N., Yuyama, M., Maeda, S., Ogawa, H., Mashiko, K., Kiyoura, Y. (2006). Genotypic identification of presumptive Streptococcus pneumoniae by PCR using four genes highly specific for S. pneumoniae. J Med Microbiol 55: 709-714 [Abstract] [Full Text]  
• Neeleman, C., Klaassen, C. H. W., Klomberg, D. M., de Valk, H. A., Mouton, J. W. (2004). Pneumolysin Is a Key Factor in Misidentification of Macrolide-Resistant Streptococcus pneumoniae and Is a Putative Virulence Factor of S. mitis and Other Streptococci. J. Clin. Microbiol. 42: 4355-4357 [Abstract] [Full Text]  
• Ho, P. L., Wong, R. C. W., Chow, F. K. H., Cheung, M. Y. M., Wong, S. S. Y., Yam, W. C., Que, T. L. (2004). Application of a multiplex pbp2b and pbp2x PCR for prediction of penicillin resistance in Streptococcus pneumoniae. J Antimicrob Chemother 53: 890-891 [Full Text]