Epidemiologia molecular de Haemophilus parasuis em rebanhos suínos brasileiros

Abstract

Forty-five H. parasuis isolates, thirty-one previously serotyped, recovered from 14 Brazilian swine herds, were genotyped by ERIC-PCR. Genomic fingerprints were analyzed and clusters were constructed to compare isolates from the same serotype, herd or site of isolation, and to value the genetic variability within categories. Twenty-two distinct genotypes (I XXII) were identified with a diversity index of D=93. Non-typable strains (NT) were the most prevalent (56,25%) and had high genetic diversity, with thirteen distinct genotypes. NT strains also had high genetic variability within herds, with two (herd M) and six (herd F) different strains from a single herd. Herd F, from which 11 isolates were evaluated, had the most diverse genotypes, with eight different strains. Fifty percent of the herds were affected by two or more genotypes. The genetic diversity among studied isolates was considerable, despite of isolation sites. Isolates from respiratory tract had 21 from 22 detected genotypes, and six isolated strains from systemic sites had four distinct genotypes. Genotype-II isolates were obtained from upper respiratory tract only, which suggested that these strains might be classified as non-virulent. Isolates obtained from systemic sites, such pericardium, pleura and brain, were serovar 5 or NT. ERIC-PCR patterns for H. parasuis isolates were highly heterogeneous, but fingerprints were useful to define strain variability within and among herds