Resurgence of Pertussis and Emergence of the Ptxp3 Toxin Promoter Allele in South Italy

BACKGROUND:Despite universal immunization programs, pertussis remains a major public health concern. This study aimed to describe the pertussis epidemiology in the Puglia region in 2006–2015 and to identify recent polymorphisms in Bordetella pertussis virulence-associated genes. METHODS:The pertussis cases in 2006–2015 were identified from the National Hospital Discharge Database and the Information System of Infectious Diseases. Samples of pertussis cases in 2014–2016 that were confirmed by the Regional Reference Laboratory were subjected to ptxA, ptxP and prn gene sequencing and, in 10 cases, multiple-locus variable-number tandem repeat analysis. RESULTS:In Puglia in 2006–2015, the pertussis incidence rose from an average of 1.39/100,000 inhabitants in 2006–2013 to 2.56–2.54/100,000 in 2014–2015. In infants