Evaluation of the Discriminatory Power of Typing Methods forNeisseria gonorrhoeae

Abstract

A panel of 18 strains of Neisseria gonorrhoeae, known to be temporally and geographically diverse, was used to evaluate a number of typing systems, including conventional auxotyping and serotyping and the molecular methods of arbitrarily primed PCR (AP-PCR), amplified ribosomal-DNA restriction analysis (ARDRA), opa typing, and pulsed-field gel electrophoresis (PFGE). The discriminatory power of the different typing methods were determined with a collection of 87 clinical isolates from commercial sex workers in Indonesia, and Simpson's index of diversity was calculated. Of the two traditional techniques, auxotyping and serotyping, the latter gives the highest discriminatory index (DI) (DI, 0.846). The combination of auxotyping and serotyping yields a high DI (DI, 0.928). D11344-and D8635-primed PCR showed low DIs of 0.608 and 0.622, respectively, but a combination of the two primers had a DI of 0.849. The combination of serotyping with D11344-primed or D8635-primed PCR resulted in DIs of 0.936 and 0.937, respectively. ARDRA revealed a low DI of 0.743 alone but a DI of 0.955 in combination with serotyping. PFGE using the restriction enzyme BglII and opa typing produced the highest discrimination (DIs, 0.997 and 0.996, respectively) for isolates of N. gonorrhoeae.

The Epidemiology of Gonorrhea Among Men Who Have Sex With Men in Stockholm, Sweden, 1990–2004

“…According to these results PFGE fingerprinting is a sharper and more discriminating epidemiologic tool than the routinely used serological typing. This is in full agreement with previous studies [82,83,87].…”

“…From each suspension 300 µL was used for preparation and digestion of the genomic DNA of the bacteria according to the manufacturer's protocol of GenePath Group 3 Reagent Kit (Bio-Rad Laboratories, Hercules, CA, USA). Two different restriction enzymes were separately used: SpeI recommended by Bio-Rad and used in previous studies [82][83][84][85][86] and BglII also used in previous studies [86,87].…”

Molecular typing of the actin gene of Trichomonas vaginalis isolates by PCR–restriction fragment length polymorphism

“…However, the overall discriminative power of the designed method was low. The actin gene may not be a suitable marker for strain discrimination if it is used on its own, but the overall discriminative power can be improved if a combination of markers for strain discrimination is used [36].…”

Evaluation of randomly amplified polymorphic DNA and pulsed field gel electrophoresis techniques for molecular typing ofDermatophilus congolensis

“…According to recent guidelines [17,20,43], a typing system should achieve a DI of >0.95 for reliable assessment of the clonal relatedness of isolates or, if typing results are to be interpreted with confidence, a DI of greater than 0.90 is desirable [20,44,45].…”