E-Poster Presentation Australian Society for Microbiology Annual Scientific Meeting 2021

Microaerobic conditions leads to increased biofilm formation in Bordetella pertussis (#334)

Hiroki Suyama 1 , Laurence D W Luu 1 , Ling Zhong 2 , Mark J Raftery 2 , Vitali Sintchenko 3 4 , Ruiting Lan 1
  1. Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales, Australia
  2. Mark Wainwright Analytical Centre, University of New South Wales, Sydney, New South Wales, Australia
  3. Centre for Infectious Diseases and Microbiology - Public Health, Institute of Clinical Pathology and Medical Research - Pathology West, Westmead Hospital, Sydney, New South Wales, Australia
  4. Marie Bashir Institute for Infectious Diseases and Biosecurity, Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia

Pertussis (whooping cough) is an acute respiratory disease caused by Bordetella pertussis. Despite widespread vaccinations globally, there has been an increase in pertussis incidence and epidemics. It has been shown globally that single nucleotide polymorphism (SNP) cluster I strains carrying pertussis toxin promoter allele ptxP3 and pertactin gene allele prn2 have overtaken the previously dominant SNP cluster II strains (non-ptxP3/non-prn2). A reason that the resurgence may have occurred is that the current vaccine may not protect against B. pertussis cells in biofilms. This study investigated the proteomic differences between a SNP cluster I and a SNP cluster II strain in biofilm conditions using tandem mass tagging (TMT) and high resolution-multiple reaction monitoring (MRM-hr). Forty differentially expressed proteins were identified in SNP cluster I including 4 cytochrome proteins (PetA, PetB, PetC and BP3650), which were all upregulated.  Interestingly, the homologs of PetABC and BP3650 cytochrome proteins have been shown to be important for survival in hypoxic conditions in other species. B. pertussis is conventionally classified as a strict aerobe and it is unclear whether the bacteria can survive in microaerobic conditions. Thus, this study further investigated the production of biomass in biofilm conditions between microaerobic and aerobic conditions using free-use green fluorescent protein (fuGFP) expression. Four representative strains each from SNP cluster I and II were used. B. pertussis was found to be able to grow in microaerobic conditions. There was an increase in overall biomass in all strains in microaerobic conditions compared to aerobic conditions. Furthermore, the previously dominant cluster II strains had a higher level of dispersed and pellicle biofilm cells while cluster I strains had increased surface attached biofilm. Lower oxygen may act as a trigger for biofilm formation for B. pertussis. Additionally, cluster I strains may survive better in lower oxygen conditions by forming stronger biofilms and this may help explain the fitness advantage over the previously dominant strains.