RESUMO
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).
RESUMO
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 (P0.05) was observed.(AU)
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 (P0.05).(AU)
Assuntos
Escherichia coli/isolamento & purificação , Escherichia coli/patogenicidade , Resistência Microbiana a Medicamentos , Anti-InfecciososRESUMO
Humans are exposed to health-impairing air pollutants, especially children who are more sensitive to cancer-causing toxins. This study described an area of reference for inhalable particulates (PM2.5) by chemical (polycyclic aromatic hydrocarbons) and mutagenic characterization associated with the genetic biomonitoring of children (aged 5-11 years). The area studied was in a small town in Brazil, used as reference in previous studies. Organic matter of PM2.5 (extracted with dichloromethane) was evaluated for mutagenesis in a Salmonella/microsome (microsuspension) assay, in strains measuring frameshift error (TA98, YG1021 and YG1024) and base pair substitution (TA100) of DNA, in the presence and absence of rat liver metabolization fraction (S9). Exposure was studied analyzing a sample of 45 children using comet assay (peripheral blood lymphocytes) and micronucleus (exfoliated buccal mucosa cells). PM2.5 concentration for the period was 9% (25.89-64.71 µg/m3) events above WHO limit value (25 µg/m3). Mutagenesis responses (revertants/m3) varied from negative (spring) to 8.3±0.69 (autumn) (-S9) and 5.4±0.36 (winter) (+S9), in strain TA98, and for TA100, in spring, from negative to 14.8±4.23 (-S9) and 17.5±2.72 (+S9). YG strain results show mononitroarenes and aromatic amines. Mean biomonitoring values were established for MN, 0.3±0.41 () and for other cell types a variation from 0.6±0.73 (), nuclear buds to 57.5±24.92 (), karyorrhexis. Comet assay means were 23.1±12.44; 7.3±11.66 and 0.9±2.30 for tail length, intensity and moment, respectively. There was no difference for sex and age for the different parameters. A significant difference in confounding factors was observed for passive smoking and MN induction. PAHs and mutagenesis in the air may be related to local vehicular emissions. These results challenge the definition of areas of reference for air pollution associated with human biomonitoring including the region studied.