The adhesin pertactin (Prn) is one of the major virulence factors of Bordetella pertussis, the etiological agent of whooping cough. However, a significant prevalence of Prn-deficient (Prn？) B. pertussis was observed in Japan. The Prn？ isolate was first discovered in 1997, and 33 (27%) Prn？ isolates were identified among 121 B. pertussis isolates collected from 1990 to 2009. Sequence analysis revealed that all the Prn？ isolates harbor exclusively the vaccine-type prn1 allele and that loss of Prn expression is caused by 2 different mutations: an 84-bp deletion of the prn signal sequence (prn1ΔSS, n = 24) and an IS481 insertion in prn1 (prn1::IS481, n = 9). The frequency of Prn？ isolates, notably those harboring prn1ΔSS, significantly increased since the early 2000s, and Prn？ isolates were subsequently found nationwide. Multilocus variable-number tandem repeat analysis (MLVA) revealed that 24 (73%) of 33 Prn？ isolates belong to MLVA-186, and 6 and 3 Prn？ isolates belong to MLVA-194 and MLVA-226, respectively. The 3 MLVA types are phylogenetically closely related, suggesting that the 2 Prn？ clinical strains (harboring prn1ΔSS and prn1::IS481) have clonally expanded in Japan. Growth competition assays in vitro also demonstrated that Prn？ isolates have a higher growth potential than the Prn+ back-mutants from which they were derived. Our observations suggested that human host factors (genetic factors and immune status) that select for Prn？ strains have arisen and that Prn expression is not essential for fitness under these conditions.
Gustafsson L, Hallander HO, Olin P, Reizenstein E, Storsaeter J (1996) A controlled trial of a two-component acellular, a five-component acellular, and a whole-cell pertussis vaccine. N Eng J Med 334: 349–355.
Junker M, Schuster CC, McDonnell AV, Sorg KA, Finn MC, et al. (2006) Pertactin beta-helix folding mechanism suggests common themes for the secretion and folding of autotransporter proteins. Proc Natl Acad Sci U S A 103: 4918–4923.
Mooi FR, van Oirschot H, Heuvelman K, van der Heide HG, Gaastra W, et al. (1998) Polymorphism in the Bordetella pertussis virulence factors P.69/pertactin and pertussis toxin in The Netherlands: temporal trends and evidence for vaccine-driven evolution. Infect Immun 66: 670–675.
Kodama A, Kamachi K, Horiuchi Y, Konda T, Arakawa Y (2004) Antigenic divergence suggested by correlation between antigenic variation and pulsed-field gel electrophoresis profiles of Bordetella pertussis isolates in Japan. J Clin Microbiol 42: 5453–5457.
Mastrantonio P, Spigaglia P, van Oirschot H, van der Heide HG, Heuvelman K, et al. (1999) Antigenic variants in Bordetella pertussis strains isolated from vaccinated and unvaccinated children. Microbiology 145: 2069–2075.
Bouchez V, Brun D, Cantinelli T, Dore G, Njamkepo E, et al. (2009) First report and detailed characterization of B. pertussis isolates not expressing pertussis toxin or pertactin. Vaccine 27: 6034–6041.
Roberts M, Fairweather NF, Leininger E, Pickard D, Hewlett EL, et al. (1991) Construction and characterization of Bordetella pertussis mutants lacking the vir-regulated P.69 outer membrane protein. Mol Microbiol 5: 1393–1404.
Leininger E, Roberts M, Kenimer JG, Charles IG, Fairweather N, et al. (1991) Pertactin, an Arg-Gly-Asp-containing Bordetella pertussis surface protein that promotes adherence of mammalian cells. Proc Natl Acad Sci U S A 88: 345–349.
Leininger E, Ewanowich CA, Bhargava A, Peppler MS, Kenimer JG, et al. (1992) Comparative roles of the Arg-Gly-Asp sequence present in the Bordetella pertussis adhesins pertactin and filamentous hemagglutinin. Infect Immun 60: 2380–2385.
van den Berg BM, Beekhuizen H, Mooi FR, van Furth R (1999) Role of antibodies against Bordetella pertussis virulence factors in adherence of Bordetella pertussis and Bordetella parapertussis to human bronchial epithelial cells. Infect Immun 67: 1050–1055.
Stefanelli P, Fazio C, Fedele G, Spensieri F, Ausiello CM, et al. (2009) A natural pertactin deficient strain of Bordetella pertussis shows improved entry in human monocyte-derived dendritic cells. New Microbiol 32: 159–166.
Aoyama T, Murase Y, Iwata T, Imaizumi A, Suzuki Y, et al. (1998) Comparison of blood-free medium (cyclodextrin solid medium) with Bordet-Gengou medium for clinical isolation of Bordetella pertussis. J Clin Microbiol 23: 1046–1048.
Cassiday P, Sanden G, Heuvelman K, Mooi F, Bisgard KM, et al. (2000) Polymorphism in Bordetella pertussis pertactin and pertussis toxin virulence factors in the United States, 1935–1999. J Infect Dis 182: 1402–1408.
Schouls LM, van der Heide HG, Vauterin L, Vauterin P, Mooi FR (2004) Multiple-locus variable-number tandem repeat analysis of Dutch Bordetella pertussis strains reveals rapid genetic changes with clonal expansion during the late 1990s. J Bacteriol 186: 5496–5505.
Litt DJ, Neal SE, Fry NK (2009) Changes in genetic diversity of the Bordetella pertussis population in the United Kingdom between 1920 and 2006 reflect vaccination coverage and emergence of a single dominant clonal type. J Clin Microbiol 47: 680–688.
Sekiya K, Ohishi M, Ogino T, Tamano K, Sasakawa C, et al. (2001) Supermolecular structure of the enteropathogenic Escherichia coli type III secretion system and its direct interaction with the EspA-sheath-like structure. Proc Natl Acad Sci U S A 98: 11638–11643.