Condições microbiológicas do ambiente e insumos de aviários e susceptibilidade de Escherichia coli a antimicrobianos naturais

Abstract

The study aimed to determine the population of Total Coliforms and Escherichia coli (E. coli) in samples of raw materials and environment of aviaries, including feed, water and bed. In the period from July to December 2014 were collected 72 samples of raw materials and environment of aviaries, it is verified the population of Total Coliforms and E. coli, the quick method of counting Petrifilm ™ (3M Company), (AOAC 998.8) and in the water samples through rapid method chromogenic Readycult® (Merck). Samples of E. coli were analyzed for the presence of virulence genes iss and iutA, using the Polymerase Chain Reaction (PCR) and subjected to antimicrobial susceptibility testing natural compounds. For the antimicrobial activity test were used essential oil extracted from leaves and inflorescence of Lippia origanoides (Kunth) and extract Agave sisalana (Perrine), using the broth microdilution test proposed by CLSI (2003) with modifications. The Total Coliforms were detected in 82.85% of environmental samples and inputs, with between 1.48 to 8.40 log UFC / g. Strains of E. coli were present in the environment and inputs in 71.42% of samples, with between 0.95 to 7.79 log UFC/g. Among the samples of the environment and inputs of poultry, the bed was configured as the sample increased microbial contamination with an average population of 5.36 log UFC/g, followed by the feed trough samples (3.00 log UFC/g), feed shed (2.60 log UFC/g) of water cooler water that was present in 78.57% of samples. The reaction to the virulence gene iutA obtained a prevalence of 92.0% in E. coli isolates and 34.0% for the virulence gene iss, obtaining concomitantly the presence of virulence genes in 34.0% of isolates. The Minimum Inhibitory Concentration (MIC) presented by the essential oil extracted from leaves and inflorescences of L. origanoides was 0.54 mg.mL-1 for pathogenic E. coli isolated from cellulitis injury, liver, water, feed and bed, considered as 17 bacteriostatic. The MIC to ATCC 25922 was 1.09 mg.mL-1, assessed as bacteriostatic. The Minimum Bactericidal Concentration (MBC) for isolated from the reaction was 1.09 mg.mL-1, liver, water and bed showed MBC 2.18 mg.mL-1, whereas cellulite injury isolated and standard strain (ATCC 25922) showed CBM 4.37 mg.mL-1 and 8.75 mg.mL-1, respectively. In counterposed, sisal extract presented no antibacterial activity in any of the evaluated the concentrations of all studied strains. Thus, considering the presence of E. coli during the production process of chicken, in view of its potential zoonotic, sets up a risk to consumers in this product. Therefore, the use of L. origanoides leaves in the production of chicken environment, allows for the inhibition and / or reduction of microbial growth, conferring a safety to the final consumer, as well as characterize a viable alternative preventive measures from synthetic antimicrobials.