genus and species identification by a combination of phenotypic and genetic characteristics method : the api rapid id 32a system was used , which is a system of identification of anaerobic bacteria in 4 hours which includes enzymatic standardized tests , miniatunzed , and a specific database . the characterization was carried out according to the manufacturer &# 39 ; s instructions . from a well isolated colony , a subculture was made in mrs agar and incubated for 48 hours in aneaerobiosis . a suspension of turbidity equal to 4 mcfarland and inoculated with a gallery of 55 μl in each cupola . the cupola of ure , with 2 drops of paraffin oil and incubated for 4 hours at 37 ° c . in aerobiosis . results . the biochemical profile showed the following results contained in table 3 . a culture of bifidobacterium animalis strain pta - 9175 was obtained after 48 hours ; it was placed in a vial containing 700 μl of a solution of 100 mm tris - hcl , 150 μg of lysozyme were added and it was incubated at 37 ° c . during 60 min in b . a . after that time , 200 μl of te1x ( 10 mm tris - hcl and 1 mm edta , ph 8 . 0 with sodium dodecyl sulfate of 1 % and 6 μl of proteinase k of 10 mg / ml concentration ) were added and incubated at 55 ° c . during 60 ° c . in a water bath . the dna was extracted by adding 500 μl of saturated phenol , 100 μl of sevag ( chloroform - isoamyl alcohol ), 200 μl of te1x , mixed by inversion each time a reagent is added and a final 5 min agitation by inversion . the sample was centrifuged at 14000 rpm during 8 minutes . from the aqueous phase the dna was precipitated with 2 . 33 volumes of 98 % ethanol at − 20 ° c . during 24 hours . after the dna was separated by centrifugation at 10000 rpm for 5 min and resuspended the dna in 50 μl of te1x . it was left in cooling for 24 hours before quantified by fluorescence at 460 nm , and finally adjusted to a concentration of 100 ng / μl with te1x . the dna concentration was determined by fluorometry and adjusted to 100 ng / ml . initiators were used : im26 f 5 ′ gattctggctcaggatgaacg - 3 ′ and im3 r 5 ′ cgggtgcticccactttcatg - 3 ′. the reaction mixture used was 25 μl , which contained , 2 . 5 μl of 10 × buffer , 1 . 5 μl of mgcl 2 50 mm , 17 . 25 μl of water , 0 . 25 μl of taq polymerase , the final concentration of dntp &# 39 ; s was 0 . 2 μm , each primer had a final concentration of 0 . 3 μl and 100 ng of dna . the conditions of pcr amplification used were 35 cycles of denaturation at 94 ° c . for 60 seconds , aligning at 57 ° c . for 120 seconds , extension at 72 ° c . for 120 seconds , and finally a final extension cycle at 72 ° c . for 3 minutes ; a thermocyclator equiment was used , model px2 thermal cycler ( thermo electron corporation , ma . u . s . a .). the detection of amplified products was performed by electrophoresis in agarose gel at 1 % ethidium bromide staining . the sequence obtained was analyzed using the program blast 2 . 2 . 14 and 99 % homology was obtained with bifidobacterium animalis . table 4 shows the list of bacteria with the homology percentage of over 95 %. the genotypification used the initiator : 5 ′- aag taa gtg act ggg gtg agc g - 3 ′. reaction mixtures were prepared with a volume of 25 μl . each sample contained the following : 200 μm of each desoxynucleoside triphosphate , 0 . 3 μm of initiator eric 2 , 50 mm of kcl , 10 mm of tris - hcl ph = 8 . 3 , 3 mm of mgcl 2 , 3 u of taq dna polymerase ( bioline , ma , usa ), 500 ng of genomic dna . the pcr conditions were as follows : initial denaturation of 1 cycle at 94 ° c . for 2 min , 40 cycles of denaturation at 94 ° c . for 20 sec , alignment at 35 ° c . for 20 sec and extension at 72 ° c . for 1 min ; and finally a final extension of 1 cycle at 72 ° c . for 1 min using a thermocyclator px2 thermal cycler ( termo electron corporation milford , mass ., u . s . a .). the amplified products were subject to electrophoresis in agarose gel at 2 % stained with ethidium bromide were revealed in uv light . the pattern of amplifying bands was analyzed with the software lab works uvp version 4 . 5 for windows . results : a characteristic pattern was obtained of bifidobacterium animalis strain pta - 9175 . the pattern is shown in fig1 . method : to determine the phenotype of resistance to antibiotics the kirby - bauer method was used . from a young culture of 18 to 24 hours several colonies were taken with a sterile swab and inoculated into a test tube with a sterile , isotonic saline solution . the inoculum was visually adjusted to a turbidity of 0 . 5 on the mcfarland scale . within 15 minutes the inoculum was adjusted , a sterile swab was introduced into the suspension and when removing it the excess liquid was eliminated . agar mueller - hinton plates were inoculated , leaving no free zone , sliding the swab across the surface of the agar 3 times , rotating the plate 60 ° each time and finally passing it over the periphery of the agar to achieve a uniform seed . the plates were left to dry for 3 to 5 min and the sensidiscs of the following antibiotics were placed : norfloxacin , cephalothin , azithromycin , tobramycin , ampicillin / sulbactam , erythromycin cefatoxim , nalidixic acid , ceftazidime , aztreonam , vancomycin , cefuroxime , rifampicyn , nitrofurantoin , oxacylin , nefilmicin amikacin , kanamycin ticarcillin , clindamycin , ampicillin . results : the results of sensibility testing are shown in table 5 . all strains with an inhibition diameter of 0 are resistant to the tested antibiotic . according to the results , it can be concluded that the strain of bifidobacterium animalis pta - 9175 is resistant to aminoglycosides . method : mrs agar plates were prepared and supplemented with human blood at 5 %. the plates were sown with bifidobacterium animalis strain pta - 9175 and incubated under anaerobe conditions for 48 hours . result : no hemolysis was observed in the developed colonies of bifidobacterium animalis strain pta - 9175 . method : a bottle was prepared with 300 ml of hcl ph 1 and added 25 ml of milk ph 4 . 5 + 1 ml of a suspension of 10 13 of bifidobacterium animalis strain pta - 9175 . gently mixed and sampled every 30 min until completing 3 hours . the samples were sown in an mrs medium and incubated under anaerobe conditions . results : development was observed in all samples taken up to 3 hours . according to this result , it can be concluded that the strain of bifidobacterium animalis pta - 9175 is resistant to the presence of acid . method : mrs agar plates were prepared and supplemented with human bile obtained by lapraoscopic cholecystectomy to final concentrations of 0 . 3 %, 1 %, 2 %, 3 %, 4 %, 5 %, 6 % and 7 . 5 %. the plates were incubated in anaerobiosis at 37 ° c . for 72 hours . moreover , a plate was sown from the same suspension of bacteria on a plate without bile . we counted the number of colonies developed in the control plates and in the bile plates , and calculated the percentage of inhibition . to determine whether the effect was bacteriostatic or bactericidal of the plates where no growth was found , a sample was taken from the agar surface with a swab to resow in an mrs medium without bile . results : on the control plate 115 colonies were developed , on plate 2 78 were developed , and on plate 3 17 colonies were developed . thus the percentages of inhibition were 67 . 8 % for the plate with 0 . 3 % bile and 14 . 8 % for the plate with 1 % bile . there was no development on the plates with 2 %, 3 %, 4 %, 5 % and 6 % bile . each of the plates where there was no development ( from 4 to 8 ), were sown with mrs agar without bile to determine whether the effect was bacteriostatic or bactericidal . there was no growth on any plate , so it is assumed that a percentage of ≧ 2 % bile has bactericidal effect on the bifidobacterium animalis strain pta - 9175 . preparation of cell culture : to obtain the volume of cells needed to confront them with the bifidobacterium animalis strain pta - 9175 , the transfer technique was used or propagation of adherent cell lines forming a monolayer of a base culture to another one . starting from a vial with a stock of each of the cells , the complete modified eagle medium ( mem ) was inoculated with fetal calf serum to 20 % and 50 μg of gentamicin per ml of complete medium for the caco - 2 and mccoy cells for cells ht - 29 . it was incubated at 37 ° c . with 5 % of co 2 and daily observed until observing a confluent growth . the culture medium was removed , and added 1 ml trypsin 0 . 25 %- edta , for each cm 2 of monolayer and allowed 1 hour of incubation at 37 ° c . until observed under the microscope that the cells were detached . the detached cells were collected in falcon tubes and the trypsin was inactivated by adding 1 . 5 ml of complete medium for each ml of trypsin used . centrifuged at 1000 rpm for 3 min and the supernatant was removed with trypsin . the botton of obtained cells was washed with a solution of pbs 1 × and again centrifuged under the same conditions . the botton of cells was smoothly resuspended in 1 ml of mem or maccoy medium for each 10 cm 2 of monolayer . from this suspension of cells aliquots were taken of 0 . 5 ml and transferred to bottles of 25 cm 2 , and 7 . 5 ml of complete medium were added . incubated at 37 ° c . in a humidified atmosphere of 5 % co 2 for 48 to 72 hours or until observing confluence in the bottles . confronting the bifidobacterium animalis strain pta - 9175 to each of the cell lines : a bottle was prepared with a suspension of bifidobacterium animalis strain pta - 9175 and 10 5 bacteria were inoculated in the bottles of cell culture with a confluent culture . the incubation continued for 24 hours and observed under the microscope to find if the bacteria are attached to the cells by gentle movements of the bottle while under observation . results : adhesion was observed of approximately 20 % of the cells to the caco - 2 cell line . for cells ht - 29 an adherence of approximately 30 % was observed . method : young cultures were obtained from s . aureus , e . coli o157 : h7 , salmonella enteritidis , campylobacter jejuni , helicobacter pylori , yersinia enterocolitica and suspensions were prepared with turbidity corresponding to tube 1 of macfarland . the bifidobacterium animalis strain pta - 9175 was cultivated in an mrs medium under anaerobic conditions at 37 ° c . for 48 hours . the suspension was made in a saline solution by adjusting the concentration to the corresponding for tube 4 of the macfarland nephelometer . the inoculum prepared was inoculated into an mrs agar of 3 mm depth per closed groove and with a swab in the center of each plate ( an area of 1 by 1 . 5 inches ). the plates were incubated in anaerobiosis at 37 ° c . for 48 hours . after that time , the plates were filled again with 10 ml of blood agar for h . pylori and with culture medium bhi for the rest of the bacteria . the medium was poured melted , sterilized and cooled to about 45 ° c ., previously inoculated with 1 ml of a suspension of the test pathogen . the agar was allowed to solidify and the plates were incubated at 37 ° c . in microaerobiosis for h . pylori and in aerobiosis for the rest of the bacteria , during 48 hours for h . pylori and 24 for the rest of the bacteria . after observing the growth inhibition of the test pathogens , samples were taken from the zone of inhibition with a sterile swab and the corresponding culture medium was resown . result : growth inhibition was detected in s . aureus , e . coli o157 : h7 , salmonella enteritidis , campylobacter jejuni , helicobacter pylori , yersinia enterocolitica through the strain of bifidobacteria animalis pta - 9175 . after observing the growth inhibition of the test pathogens , samples were taken from the zone of inhibition with a sterile swab and the corresponding culture medium was resown . growth was observed in all the reseedings that were carried out , which showed that the effect of bifidobacterium animalis strain pta - 9175 is bacteriostatic and not bactericidal . plasmids are extrachromosomal dna elements that replicate intracellularly and independently , although in most cases they are not essential for the viability of the cell , they contain genes that confer different properties such as antibiotic resistance , virulence or metabolic activities . for the investigation of plasmids from bifidobacterium animalis strain pta - 9175 , the extraction of plasmid dna was carried out by alkaline lysis and visualization by agarose gel electrophoresis . next , the procedure used is described . method : a young culture was resuspended in the strain of bifidobacteria animalis pta - 9175 in 200 μl of lysis absorber : solution i ( glucose 50 mm , tris - hcl 25 mm ph = 8 , edta 10 mm ). after 5 min at room temperature , 400 μl of a freshly prepared alkaline solution were added ( 0 . 2 n naoh , 1 % sds ) and mixed by inversion from 3 to 6 times . the tube was placed in ice for 5 min , added 300 μl ammonium acetate 7 . 5 m ph = 7 . 8 and the tube content was mixed by gentle inversion for a few seconds . the tube was kept in ice for 10 min to allow the majority of proteins , the high molecular weight rna and the chromosomal dna to precipitate . afterwards , it was centrifuged for 9 min at 14000 rpm and the supernatant was removed to a clean tube . 650 μl of isopropanol was added and incubated at room temperature for 20 to 30 min . then , centrifuged at 14000 rpm for 15 min , the supernatant was decanted , the pellet was washed by inversion with 500 μl of 70 % ethanol , centrifuged for 3 min at 14000 rpm and the inverted tubes were left on a sheet of paper for 14 min to dry . the pellet was dissolved in 50 to 100 μl of 1 × te , 5 μl rna &# 39 ; sa of 1 mg / ml was added , and incubated for 15 min at 37 ° c . a gel was run in agarose at 2 % to detect the presence of genetic material . results : in the gel electrophoresis no genetic material was detected corresponding to plasmids . method : the hydrolase activity of bile salts was carried out by determining the release of amino acids of the bile salts . a young culture was resuspended in the strain of bifidobacteria animalis pta - 9175 in a phosphate absorber ph = 7 and centrifuged at 10000 rpm at 4 ° c . the cells were washed twice with a sodium phosphate absorber ph = 7 and resuspended in the same absorber to obtain a density of 5 to 10 optical units at 600 nm . ten ml of this cell suspension was sonicated for 3 min and the mixture was centrifuged for 10 min at 20000 rpm . the supernatant was retained as a cell - free extract . 180 μl of aborber was mixed ( 0 . 1 m sodium phosphate ph = 6 ) with a sample of 10 μl of a human bile salt mixture , and heated to 37 ° c . a sample of 50 μl was taken after 10 and 30 min and the sample was immediately mixed with tca at 15 %. these samples were centrifuged at maximum speed to remove the precipitate . for the second reaction , an aliquot of the supernatant was mixed with water to obtain a volume of 100 μl ( 20 of sample and 80 of water ). to this mixture 1 . 9 ml of ninhydrin was added to a sodium citrate absorber of 0 . 5 m ph = 5 . 5 , 1 . 2 ml of glycerol and 0 . 2 ml sodium citrate absorber ph = 5 . 5 . this was strongly mixed and boiled for 14 min . next , the tubes were cooled and the absorbance was measured at 570 nm . strains of lactobacillus , enterococcus and bacteroides were used as controls of the production of bile hydrolase . the tests were performed in duplicate . results : bile hydrolase activity was detected in the strains used as positive controls . not any activity was detected in bifidobacterium animalis strain pta - 9175 . conclusions : the ability of probiotic bacteria to hydrolyze bile salts has been included among the criteria for selection of bacteria such as probiotics , and a wide range of bile salt hydrolases has been identified and characterized . however , the activity of this enzyme has also shown a harmful effect on the host and that some pathogenic bacteria such as l . monocytogenes and other potencially patogenes as enterococcus faecalis produce it . method and results : we used balb / c mice , male , purchased from harlan - mexico , 6 weeks of age . a culture was prepared of 20 h of bifidobacterium animalis strain pta - 9175 in milk medium ( 10 % skim milk , cysteine hydrochloride at 0 . 05 % and yeast extract at 0 . 5 %). this culture was used to administer doses to the animals . the doses and frequency are detailed below . stage 1 . without cyclophosfamide group 1 . 10 mice inoculum : 10 10 twice daily for 18 days ( 0 . 2 ml / oral ) weight at the beginning of the treatment : 21 . 05 gr weight at the end of the treatment : 19 . 58 gr 1 . 47 gr of weight lost group 2 . 10 mice inoculum : 10 10 twice daily for 24 days ( 0 . 2 ml / oral ) weight at the beginning of the treatment : 21 . 74 gr weight at the end of the treatment : 22 . 77 gr 1 . 03 gr of weight gained group 3 . 10 mice inoculum : 10 10 twice daily for 18 days ( 0 . 2 ml / oral ) weight at the beginning of the treatment : 22 . 32 gr weight at the end of the treatment : 21 . 09 gr 1 . 23 gr of weight lost group 4 . 10 mice inoculum : 10 10 twice daily for 24 days ( 0 . 2 ml / oral ) weight at the beginning of the treatment : 23 . 09 gr weight at the end of the treatment : 23 . 8 gr they won : 0 . 71 gr of weight stage ii . with cyclophosfamide ( 200 mg / kg every 7 days )/ ip ( permanent neutropenia ) group 1 . 10 mice inoculum : 10 10 twice daily for 18 days ( 0 . 2 ml / oral ) weight at the beginning of the treatment : 22 . 23 gr weight at the end of the treatment : 19 . 06 gr lost : 3 . 17 gr of weight inoculum : 10 10 twice daily for 24 days ( 0 . 2 ml / oral ) weight at the beginning of the treatment : 21 . 88 gr weight at the end of the treatment : 19 . 68 gr lost : 2 . 20 gr of weight group 3 . 10 mice inoculum : 10 10 twice daily for 18 days ( 0 . 2 ml / oral ) weight at the beginning of the treatment : 20 . 84 gr weight at the end of the treatment : 17 . 17 gr lost : 3 . 67 gr of weight group 4 . 10 mice inoculum : 10 10 twice daily for 24 days ( 0 . 2 ml / oral ) weight at the beginning of the treatment : 20 . 97 gr weight at the end of the treatment : 19 . 75 gr lost : 1 . 22 gr of weight handling of animals at the end of the periods as indicated . at the end of the periods indicated , the animals were sacrificed by cervical dislocation . extracted esophagus , stomach , cecum , kidney , spleen , liver . these were placed in jars with formaldehyde and sent for anatomopatologic study . observations in the animals during the study : during the study , the mice from the group without cyclophosphamide had no fever , no change in behavior , or changes in fur . during the study , the mice from the group with cyclophosphamide had no fever , nor did they present any changes in fur , and their behavior was to remain in group for long periods . in the organs removed no macroscopic changes were observed in color nor in size . there was no abscess formation . in the histological study no presence of bacteria was found in any of the samples . no histological changes were seen with inflammation . alterations were detected stress - related in liver and spleen . conclusions : under the conditions of this study , oral administration in normal mice and mice treated with cyclophosphamide with bifidobacterium animalis strain pta - 9175 showed no visible toxicity . selection of individuals : we assessed 24 healthy individuals who underwent single stool parasite search and complete examination to confirm their good health including blood sampling for conducting baseline blood chemistry ( glucose , urea and creatinine ), a complete hematic biometry , and a pregnancy test for the women . all individuals of the study showed normal values in blood chemistry parameters and in hematologic biometry . the individuals were divided randomly into two groups to receive a placebo ( group a ) ( n = 13 , mean age = 25 , range = 19 - 50 , f / m = 7 / 6 ) or the yogurt supplemented with the bifidobacterium animalis strain pta - 9175 ( group b ) ( n = 11 , mean age = 24 , range = 19 - 33 , f / m = 8 / 3 ). design phase : this phase lasted two weeks , during which they were given two bottles of yogurt daily of 250 ml each according to the test group . clinical assessment : the individuals were instructed to refer any change in bowel habits or intake of any medication that could interfere with the study . collection of stool samples : after one to two weeks of the ingestion of yogurt stool samples were collected to search for bifidobacteria and its molecular typification . the first and second week of study , 3 colonies were identified as bifidobacteria of each patient and each was grown for biomass collection , dna extraction and molecular identification using a pcr . all strains were subjected to genotypification using the primer 5 ′- aag taa gtg act ggg gtg agc g - 3 ′ for identification of the characteristic pattern . to complement the study , the cultivation , dna extraction and genotypification by eric - pcr were carried out in the strain of bifidobacterium animalis pta - 9175 that was administered . leukocyte count : no differences were observed in the counting of the leukocytes between the sample of baseline blood and the sampling of the first study week in none of the two study groups ( p & lt ; 0 . 05 ). weight : no increase nor decrease in weight was detected during the two weeks of study in any of the two groups ( p & lt ; 0 . 05 ). blood pressure : no increase nor decrease in the blood pressure weight was detected during the two weeks of study in any of the groups . bristol scale . in group a , 4 patients increased to a value on the scale of bristol and the rest remained unchanged . in group b , 1 patient increased one value on the scale of bristol . the rest remained unchanged . stool color : no changes in stool color in any of the study groups . stool consistency : 5 patients in group a improved stool consistency , and in group b 5 patients improved stool consistency . number of stools : there was no difference in the frequency of stools between the study groups ( p & lt ; 0 . 05 ). ( p & lt ; 0 . 05 ). number of stools : there was no difference in the frequency of stools between the study groups ( p & lt ; 0 . 05 ). ( p & lt ; 0 . 05 ). satisfaction after the first and second week of intake of yogurt : in group a , two subjects reported feeling very well after two weeks of consumption of yogurt . two individuals mentioned they felt very well . in group b , one person mentioned he felt regular the first week , and in the second week one of them said to feel fine . all other reports mentioned that people felt well . constipation : one patient in group a and one patient in group b reported constipation in the first week of consumption of the yogurt . constipation got resolved by the second week of eating yogurt . abdominal pain : in group a , no individual reported abdominal pain . in group b , one person reported a mild abdominal pain which persisted during the second week . postprandial satiety : in group a there were no reports of postprandial satiety . in group b , two patients reported postprandial satiety in the first week , which disappeared the second week of consumption of the yogurt . flatulence : there was no difference in the presence of flatulence between the study groups . abdominal distension : none of the individuals in group a showed any abdominal distension . one of the persons in group b showed abdominal distension in the first week of the product consumption , which disappeared the second week of consumption of the yogurt . adverse effects : two patients in group a developed fever during the study . neither needed antibiotics , and therefore they continued in the study . one of the patients had a clinically documented viral pharyngitis . the other patient had a febricula that developed with myalgia and arthralgia . the discomfort was gone in about 6 hours . analysis of bifidobacteria : we carried out a genotypification of all strains of bifidobacteria recovered and found a characteristic pattern of bifidobacterium animalis strain pta - 9175 in 5 persons from group b and in none of the persons from group a . conclusion : in the human studies no data were found to suggest infectivity of bifidobacterium animalis strain pta - 9175 . from the above results , we conclude that the strain of bifidobacterium animalis pta - 9175 of the invention has the desirable characteristics of a probiotic strain , as : it corresponds to the species bifidobacterium animalis , which has proven probiotic activity in several publications . it is of human origin , particularly from the feces of infants . it is not hemolytic . its morphology is of a gram - positive bacterium in the form of a non - porulated bacillus . its level of folic acid production is from 120 ng / ml to 398 ng / ml . it resists the presence of bile , even in small quantities . it is resistant to gastric ph . it is able to attach to intestinal cells . it inhibits the in vitro development of various pathogenic bacteria . it demonstrated safety when administered in immunosuppressed animals . it showed that it is safe for administering to humans . it has no plasmids . below are examples of achievements for food preparation containing bifidobacterium animalis strain pta - 9175 . a preparation method for producing fermented milk food products , for example , yogurt containing bifidobacterium animalis strain pta - 9175 , is to add for its cultivation at least 25 % of culture of bifidobacterium animalis strain pta - 9175 to the total volume of full milk , reconstituted milk , whey or skimmed milk and mix them ; then later add the fruit flavor , water , sweeteners , flavorers or fruit pulp requested , in order to produce a new milk drink , and shake it . the amount of culture of bifidobacterium animalis strain pta - 9175 added may vary and could be added in greater or lesser amount . all the ingredients to grow a strain of bifidobacterium animalis pta - 9175 are of a food grade , so that the culture is 100 % safe and can be consumed directly after you have added the desired taste . in foods such as cheese , the culture of bifidobacterium animalis strain pta - 9175 can be added in the last phase of the product elaboration . in other products such as powdered milk , juices , coffee , soft drinks , powders for drinks , desserts , processed meats , sweets , etc ., the culture of bifidobacterium animalis strain pta - 9175 can be liodilzated and after once obtained the powder it van added to sais products in the final stage , where it should not be submitted to a later process of heating . in the case of frozen and prepared foods , the culture may be added once the product is ready for consumption . it is important not to add the culture of bifidobacterium animalis strain pta - 9175 if the food will be subjected to heating . in an alternative embodiment the food product may also include other probiotic bacteria related to bifidobacterium animalis strain pta - 9175 . in another embodiment , the bifidobacterium animalis strain pta - 9175 can be used to prepare a pharmaceutical product for the treatment of the deficiency in folic acid . based on the embodiments described above , it is contemplated that modifications of the embodiments described , as well as alternative embodiments will be considered obvious to a person skilled in the art of the art under this description . it is therefore considered that the claims cover said modifications and alternatives that are within the scope of this invention or their equivalents .