Prevalence and molecular characterization of pertactin-deficient Bordetella pertussis in the US.

Pawloski LC, Queenan AM, Cassiday PK, Lynch AS, Harrison M, Shang W, Williams MM, Bowden KE, Burgos-Rivera B, Qin X, Messonnier N, Tondella ML.

Source

Meningitis and Vaccine Preventable Diseases Branch, Centers for Disease Control and Prevention, Atlanta, GA 30333.

Abstract

Pertussis has made a striking resurgence in the US, returning to record numbers of reported cases last observed in the 1950s. Bordetella pertussis isolates lacking pertactin, a key antigen component of the acellular pertussis vaccine, have been observed, suggesting that B. pertussis is losing pertactin in response to vaccine immunity. Screening of 1300 isolates from outbreak and surveillance studies (historical isolates collected from 1935 up to 2009, the 2010 California pertussis outbreak, US isolates from routine surveillance between 2010-2012, and the 2012 Washington pertussis outbreak) by conventional PCR and later by Western blot and prn sequencing analyses ultimately identified 306 pertactin-deficient isolates. Of these pertactin-deficient strains, 276 were identified as having an IS481 in the prn gene (prnIS481-positive). The first prnIS481-positive isolate was found in 1994, with the next prnIS481-positive isolates not detected until 2010. Pertactin-deficient isolates increased substantially to over 50% in 2012. Sequence analysis of pertactin-deficient isolates revealed various types of mutations in the prn gene, including two deletions, single nucleotide substitutions resulting in a stop codon, an inversion in the promoter, and a single nucleotide insertion resulting in a frame shift mutation. All but one mutation type were found in prn2 alleles. CDC013 was a predominant PFGE profile in the pertactin-positive isolates (203/994), but was found in only 5% (16/306) of the pertactin-deficient isolates. Interestingly, PFGE profiles CDC002 and CDC237 represented 55% (167/306) of the identified pertactin-deficient isolates. These results indicate that there has been a recent, dramatic increase in pertactin-deficient B. pertussis isolates throughout the US.