Microbiota presente em abscesso solear, perfil de susceptibilidade a antimicrobianos e de lesões de dermatite digital emprego da PCR para detectar bactérias espiraladas em bovinos de aptidão leiteira em Minas Gerais

Abstract

With the purpose to determine the microorganisms present in the sole abscess, the profile of antimicrobial susceptibility of bacterial samples isolated and for the digital dermatitis lesions a PCR to deteced spirochaetes, from 9 clinical specimens collected from dairy cattle affected by sole abscess, from three distinct farms it was possible to identify 108 bacterial samples. Among the facultative anaerobes, representing 107 samples, the Enterobacteriaceae family was the most prevalent, representing 75.0% of the samples identified. Among them, Escherichia coli represented (35.2%) of the samples identified, Klebsiella oxytoca (12.1%) and Enterobacter cloacae (8.3%). Proteus vulgaris, Citrobacter freundii, Enterobacter agglomerans, Cronobacter sakazakii, Escherichia fergusoni, Klebsiella pneumoniae. Of the Gram-positive bacilli facultative anaerobes, it could be highlighted the presence of the Bacillus spp (9.2%), Corynebacterium aquaticum (3.7%) and, less frequently, C. minutissimum, Brevibacterium spp and Listeria grayi. Among the Gram-positive cocci, Enterococcus faecalis (2.7%) was identified. Fusobacterium spp was also identified among the Gram-negative bacilli, strict anaerobe. The diversity of microorganisms present in sole abscesses indicates its polymicrobial etiology. Concerning the profile of antimicrobial susceptibility from 67 samples of animals coming from 2 farms (2 and 3), it was found that 12 out of 13 E. coli samples from farm 2 showed to be resistant to ampicillin / sulbactam and tetracycline, while 22 out of 25 samples of E. coli from farm 3 were sensitive to ampicillin / sulbactam and 11 out of 25 samples were sensitive to tetracycline. In this farm, it was also seen that 8 out of 14 samples of K. oxytoca tested were sensitive to ampicillin / sulbactam and 11 over 14 were sensitive to tetracycline; 8 from 9 samples of E. cloacae proved to be resistant to ampicillin / sulbactam and 7 were sensitive to tetracycline; the 3 samples of C. sakazakii 2 were resistant to ampicillin / sulbactam and 3 were sensitive to tetracycline. The 2 samples of E. faecalis from farm 2 and one sample form farm 3 were sensitive to ampicillin / sulbactam and resistant to tetracycline. The were found variations in the susceptibility profile to ampicillin / sulbactam and tetracycline among samples originated from the same farm and from two different farms. The DNA extracted from pure cultures of two samples of spirochaetes isolated from biopsies of 2 animals with digital dermatitis, from farm 1, was amplified by PCR and a 900 bp fragment was obtained. The analyses of the nucleotide sequences added to the results obtained by the construction of phylogenetic trees allow us to say that the animals had digital dermatitis caused by microorganisms difficult to cultivate. It was found a similarity of 99% of these sequenced samples with non-cultivable microorganisms, 75% similarity to Treponema denticola, 70% with Treponema phagedenis and 68% with Treponema pedis. PCR was also performed using DNA samples extracted from biopsies of 6 animals affected by digital dermatitis in the farm 4 and a 900pb fragment was also amplified. Data obtained allow suggesting that specific PCR would be useful to confirm the diagnosis of digital dermatitis.