Rapid typing of neonatal isolates using polymerase chain reaction for repeat regions in surface protein genes

A. Ohlin (1) , A. Bäckman (2) , B. Söderquist (3) , S. Wingren (4) , M. Björkqvist (4, 1)

1 Department of Paediatrics
2 Clinical Research Centre
3 Department of Clinical Microbiology
4 School of Health and Medical Sciences

is a significant pathogen in neonatal sepsis and other nosocomial infections. For further investigations of the colonisation patterns and invasive pathways, typing methods that are applicable on large populations of bacterial isolates are warranted. In the present study, a genotyping method based on polymerase chain reaction (PCR) for the repeat regions of four genes (, , and ) that encode for bacterial surface proteins was developed and applied to a sample of well-characterised neonatal blood isolates of ( = 49). The PCR products were visualised on agarose gel (, and ) or by fragment analysis (). The discriminatory index (D-index) for genotyping of the different genes was compared to genotyping by pulsed-field gel electrophoresis (PFGE). The highest D-index for the PCR-based typing methods was found for the combination of , and (D-index 0.94), whereas the optimal two-gene combination ( and ) resulted in a D-index of 0.92. We conclude that the described method can be used for the genotyping of large populations of isolates with a sufficient discriminatory capacity, and we suggest that the combination of and is the most suitable to use.

Mots clés: Life Sciences

A. Ohlin, A. Bäckman, B. Söderquist, S. Wingren, M. Björkqvist. Rapid typing of neonatal isolates using polymerase chain reaction for repeat regions in surface protein genes. European Journal of Clinical Microbiology and Infectious Diseases, 2010, 29 (6), pp.699-704. ⟨10.1007/s10096-010-0917-z⟩. ⟨hal-00584832⟩