Isolation and characterization of lactic acid bacteria from feces of healthy dogs.

FERNANDEZ J.M.G.,; MUZZOLÓN J.,; DALCERO A.M.; MAGNOLI C.E.

San Miguel de Tucumán

Simposio; III Simposio Internacional de Bacterias Lácticas; 2009

Cerela, Conicet

Lactic acid bacteria (LAB) are a broad group of Gram-positive, non-sporing rods and cocci, usually non-motile, catalase and oxidase negative that ferment carbohydrates forming lactic acid as the major end-product. One of the most common causes of intestinal disorders in dogs is small intestinal bacterial overgrowth (SIBO). This involves increased numbers of a mixed normal flora, most commonly with the members of the family Enterobacteriacae as well as with Bacteroides spp., Clostridium spp., and staphylococci. It has been shown that some LAB have probiotic properties for humans and animals; besides, benefic effects have been suggested for the gastrointestinal system maintenance in dogs. According to this, the aims of this work were: 1) LAB isolation and identification from the intestine of healthy dogs, b) to analyze the antibiotic resistance, c) to determine the capability of the strains to produce antimicrobial substances and to auto aggregate.  One gram of feces from 10 clinically healthy adult dogs was serially diluted in PBS (pH 7.2). Aliquots of the serial dilutions were inoculated onto MRS and incubated in a micro aerophilic chamber at 37°C for 72 h. Colonies were identified as LAB based on colonial morphology, gram stain appearance, catalase, oxidase, indol and gelatinase reaction. Stock cultures of the LAB strains were maintained at -20ºC in MRS supplemented with 30% of glycerol. Antibiotic sensitivity/resistance of 14 isolates was tested using the agar disc diffusion method and following discs (Britania) were used: ampicillin, chloramphenicol, gentamicin, vancomycin, streptomycin, ciprofloxacin. Antimicrobial activity was detected using the agar diffusion technique. The indicators strains used were Enterobacter spp., S. aureus., E. coli and Klebsiella spp isolated from ill dogs. Auto-aggregation was performed on 6 selected strains. Twenty-three strains of possible LAB were isolates. The 78% of the studied strains were Gram (+) cocci in pairs. The rest were long and thin Gram (+) non- sporing rods. Catalase, oxidase, indol, gelatinasa and motility test were negative. The 87% of the strains maintained in glycerol were recovered. The 93% of the strains showed inhibitory activity to all the marker strains assayed. Antibiotic resistance varied depending on the strain. Most strains were mainly sensitive to ampicillin and resistant to gentamycin. The 6 strains were auto aggregated in a 50-60%. This results show that some of the isolated strains from feces of dog can be selected for forward studies that may, in the future, corroborate their efficiency as potencial probiotics in order to be added to dogs food to improve their quality of life.