Coxiella burnetii in central Italy: novel genotypes are circulating in cattle and goats

Abstract

Genotyping of bacteria is critical for diagnosis, treatment, and epidemiological surveillance. Coxiella burnetii, the etiological agent of Q fever, has been recognized to have a potential for bioterrorism purposes. Because few serosurveys have been conducted in Italy, there is still limited information about the distribution of this pathogen in natural conditions. In this paper, we describe the genotyping of C. burnetii strains by multispacer sequence typing (MST) detected in cattle and goat farms in the Abruzzi region of Italy. Biological samples (milk, aborted fetus) positive for C. burnetii DNA were sequenced in the spacer regions and compared with those already publicly available ( http://ifr48.timone.univ-mrs.fr/MST_Coxiella/mst/group_detail ). The MST profile of C. burnetii detected in milk samples demonstrated the presence of a new allele, whereas the C. burnetii spacer sequences from fetus and milk goat samples displayed a new allelic combination. The results suggest the circulation of novel genotypes of C. burnetii in Italy.

Keywords: Cattle–Goat; Coxiella burnetii; Genotyping; Italy; Multispacer sequence typing.

FIG. 1.

Map of the sampling area. Geographical distribution of the three farms in the Abruzzo region, Central Italy. (1) Cow farm 1 located in Pescara province; (2) goat farm 2 located in Scanno, L'Aquila province; (3) goat farm 3 located in Avezzano, L'Aquila province.

FIG. 2.

Phylogenetic analysis. The evolutionary history was inferred using the unweighted pair group method with arithmetic mean (UPGMA) method (Sneath and Sokal 1973). The optimal tree with the sum of branch length=0.02463836 is shown. The evolutionary distances were computed using the Tajima–Nei method (Tajima and Nei 1984) and are in the units of the number of base substitutions per site. The analysis involved 37 nucleotide sequences. All positions with less than 0% site coverage were eliminated; that is, fewer than 100% alignment gaps, missing data, and ambiguous bases were allowed at any position. Evolutionary analyses were conducted in MEGA6 (Tamura at al. 2013). The tree was drawn according to Hornsta et al. (2011) and rooted according to Pearson et al. (2013).