Poster Presentation Australian Society for Microbiology Annual Scientific Meeting 2014

A novel variant of the Neisseria gonorrhoeae penicillinase-producing plasmid (#442)

Ella Trembizki 1 , Cameron Buckley 1 , Andrew Lawrence 2 , Monica Lahra 3 , David Whiley 1
  1. Queensland Children's medical research institute, Herston, QLD, Australia
  2. Microbiology and Infectious Diseases Directorate, SA Pathology, Adelaide, South Australia, Australia
  3. WHO Collaborating Centre for STD, SEALS, Prince of Wales Hospital, Sydney, NSW, Australia

Neisseria gonorrhoeae penicillinase-producing (PPNG) plasmid is responsible for dissemination of high-level penicillin resistance among gonococci worldwide. The first PPNG plasmid was isolated in South-East Asia, named the ‘Asian’ plasmid, and is 7426 base-pair (bp) in size. Further variants of the ‘Asian’ plasmid have since been described and named on the basis of their isolation origin; the ‘African’ (5599 bp), ‘Rio-de-Janerio/Toronto’ (5154 bp), ‘Nimes’ (6798 bp), ‘New-Zealand’ (9309 bp) and ‘Johannesburg’ (4865 bp) plasmids. This sub-study was conducted as part of a NHMRC-funded study titled GRAND (Gonorrhoea Resistance Assessment via Nucleic acid Detection). This study examined the conservation of sequence targets utilised by a previously described PPNG real-time PCR assay and used to detect PPNG strains in non-cultured but PCR positive clinical samples. The assay acts as an indirect marker of penicillinase activity, by amplifying a region of sequence predicted to be conserved across all known PPNG plasmid types, while not specifically targeting the penicillinase (bla) coding sequence. This study used the PPNG-PCR to screen 351 PPNG isolates from reference laboratories throughout Australia for the first six months of 2012 which comprised approximately 98% of all PPNG strains isolated in Australia in this time period. In total 350/351 (99.7%) of isolates provided positive results by the PPNG-PCR, however one isolate from South Australia provided negative results. Complete DNA sequencing of this plasmid sequence revealed a plasmid of 3269 bp, the smallest such gonococcal plasmids described to date. Notably, the plasmid exhibited a previously undescribed 1885bp deletion which omitted the PPNG-PCR oligonucleotide targets.While the prevalence of gonococci carrying this plasmid in our population is suggested to be very low, the failure to detect this novel ‘Australian’ plasmid by the PPNG-PCR further highlights the challenges of using molecular methods for N. gonorrhoeae diagnostics and characterisation.