Antimicrobial susceptibility and pathogenicity of Escherichia coli strains of environmental origin / Suscetibilidade antimicrobiana e patogenicidade de amostras de Escherichia coli de origem ambiental

The study aimed to evaluate the antimicrobial susceptibility of 109 samples of Escherichia coli (E. coli) of environmental origin and to characterize these isolates according to the degree of pathogenicity in vivo, verifying a possible relationship between this variable and susceptibility to the active principles tested. The isolates were subjected to disc diffusion test to 14 antibiotics. From 16.5% to 90% of the samples were sensitive; 1 - 28.5% showed intermediate degree of susceptibility and between 9 to 78% of E. coli analyzed were resistant. The highest resistance percentages were seen in the class of quinolones and tetracyclines (>75%), and for sensitivity in the class of amphenicols (68.8%). By inoculating 1- day - old chicks, the isolates were classified as highly pathogenic (2.7%), intermediate (10.1%), low (42.2%) and apathogenic (45%). It was observed a wide variation in the susceptibility profile of isolates in relation to antimicrobials. It was also found that most of the samples had pathogenic potential (55%), thus being considered as APEC (avian pathogenic E. coli). No relationship between pathogenicity and antimicrobial susceptibility (P≤0.05) was observed.

O estudo teve como objetivo avaliar a suscetibilidade antimicrobiana de 109 amostras de Escherichia coli (E. coli) de origem ambiental frente a antibióticos e caracterizar esses isolados quanto ao grau de patogenicidade in vivo, verificando-se uma possível relação entre esta variável e a suscetibilidade aos princípios ativos testados. Os isolados foram submetidos ao teste de disco-difusão para 14 antibióticos. Entre 16.5% a 90% das amostras foram sensíveis, 1-28.5% apresentaram grau de suscetibilidade intermediário e entre 9-78% das E. coli analisadas foram resistentes. Os maiores percentuais de resistência foram encontrados para a classe das quinolonas e das tetraciclinas (>75%), e de sensibilidade para a classe dos anfenicóis (68.8%). Por meio da inoculação em pintinhos de um dia de idade, os isolados foram classificados como sendo de patogenicidade alta (2.7%), intermediária (10.1%), baixa (42.2%) e apatogênicos (45%). Foi observada uma ampla variação no perfil de suscetibilidade das amostras frente aos antimicrobianos. Verificou-se também que a maioria apresentou potencial patogênico (55%), sendo, portanto, consideradas APEC (E. coli patogênica para aves). Não foi observada relação entre a patogenicidade e a suscetibilidade aos antimicrobianos (P≤0.05).

The constitutive expression of the V gene of Parainfluenza virus 5 affects the growth properties of bovine herpesvirus 5

This study aimed to analyze the effect of the expression of Parainfluenza virus 5 (PIV5) V protein in bovine cells on the replication of Bovine herpesvirus 5 (BoHV-5). Growth properties of BoHV-5 were evaluated in parental and PIV5 transfected cells. In one-step growth experiments, the BoHV-5 reached higher titers at earlier time points in the transfected cells when compared to the parental cells. The mean plaque size produced by the BoHV-5 in transfected cells was larger than the parental cells. This indicated that the expression of the PIV5 V gene facilitated the release and cell-to-cell spread of BoHV-5 in bovine cells.