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Salmonellosis in calves is a bacterial disease that affects their digestive tract causing diarrhea. A cross-sectional epidemiological study was carried out with the aim of studying the prevalence of various serovars of Salmonella in calves and their relationship with diarrhea signs. The study was conducted in Mar and Sierras Dairy Basin located in Buenos Aires province, Argentina. Seven hundred and twenty six calves both with diarrhea signs or not were sampled by rectal mucosa swab in 50 dairy farms during the rearing period. Isolates identified as Salmonella spp. were classified using polyvalent and monovalent antisera against somatic, flagellar and capsule antigens (Vi). Salmonella spp. was found in 36% of the farms and serotypes were: S. Mbandaka, S. Anatum, S. Typhimurium, S. Dublin, S. Montevideo, S. Meleagridis, S. Newport, S. Seftemberg, S. subesp. 16,7:z1, S. Infantis, S. Give. A percentage of 5.5% calves was positive and calves showing diarrheal signs were 5.9 times more likely to be infected with Salmonella spp. than those having no signs. The age of positive calves ranged from the first day of life to 53; the second day being the most frequent time. In conclusion, 11 Salmonella serovars were detected in one out of 3dairy farms in Mar and Sierras Dairy Basin, and not only were these serovars associated with diarrhea signs including the presence of mucus in feces, but they were also more prevalent among calves aged up to 21 days., (Copyright © 2018 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.)

Control eradication campaigns of bovine tuberculosis based on the «test and slaughter» approach were successful in many countries and regions; however, in some areas the infection persists and one of the main reasons is Mycobacterium bovis infection in wild life species. Argentina has applied the same approach since 1999, achieving progress in dairy cattle herds. Nonetheless, the wildlife role has never been investigated. The objective of this study was to determine if wildlife from the Santa Fe dairy area is infected with M. bovis. Wildlife species having a positive tuberculin skin test were captured in five dairy farms. Ninety five wildlife mammals were captured; M. bovis was recovered from 7 possums (Didelphys albiventris), from one fox (Lycolapex gimnocercus) and from one rat (Rattus norvegicus). None of the animals exhibited macroscopic lesions. The most frequently isolated M. bovis spoligotypes were types 34 (4 isolates) and 12 (3 isolates). Spoligotype 34 is the most frequently isolated type in Argentine cattle. The role of D. albiventris as spillover host of M. bovis is discussed in this study., (Copyright © 2015 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.)

Escherichia coli O157 is an emergent pathogen associated with diarrhea, hemorrhagic colitis and hemolytic uremic syndrome. Meat products constitute an important transmission source of this microorganism. The aims of this study were to characterize E. coli O157 isolated from cattle and meat products collected from abattoirs and retail stores, to establish the clonal relatedness among regional isolates and to compare them with those in the national database. Between 2004 and 2013, 169 minced meat, 35 sausage and 216 carcass samples were analyzed. Thirteen E. coli O157 isolates were identified; 6 of which were O157:H7 and characterized as stx2c(vh-a)/eae/ehxA (n = 5) and stx2/eae/ehxA (n = 1). The 7 remaining isolates were non-toxigenic E. coli strains, and serotyped as O157:NT (n = 4), O157:NM (n = 1), O157:ND (n = 1) and O157:H16 (n = 1). The strains yielded different XbaI-PFGE patterns. Compared to the E. coli O157 isolates in the National Database, none of these patterns have been previously detected in strains of different origin in Argentina., (Copyright © 2014 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.)

Introduction: Listeria monocytogenes is an intracellular, opportunistic pathogen which can cause severe infections such as meningitis, encephalitis and bacteremia. It can also cause abortions in human beings. Foods are the vehicle for infection of the host. Serotypification has discriminated 13 serotypes: 1/2a,1/2b, 1/2c, 3a, 3b, 3c, 4a, 4ab, 4b, 4c, 4d, 4e, 7. 4b is the cause of the majority of cases of listeriosis in the world., Objective: The frequency of serotypes of L. monocytogenes was determined in bacteria isolated from foods in Colombia., Materials and Methods: The study is descriptive and retrospective. Over a 10-year period, 2000-2009, 1,599 isolates were examined. All were confirmed as Listeria monocytogenes and other strains of Listeria, using biochemical tests recommended by the Food and Drug Administration (USA) and API Listeria and serotyped using the Seeliger and Höhne method., Results: Of the 1,599 isolates, 1,424 were confirmed as L. monocytogenes. Serotypes identified were: 1/2a, 135 (9.5%); 1/2b, 154 (10.8%); 1/2c, 68 (4.8%); 3a, 4 (0.3%); 3b, 29 (2.0%); 3c, 2 (0.1%); 4a, 44 (3.1%); 4b, 820 (57.6%); 4c, 6 (0.4%); 4d- 4e, 140 (9.8%); 4e, 17 (1.2%); 7, 2 (0.1%); not susceptible of serotypification, three cases, (0.2%). Isolates came mainly from the Capital District of Bogotá, 1,035 (73%); from Antioquia 199 (14%), from Nariño, 109 (8%); from Valle del Cauca 50 (3,5%) and from other provinces 33 (2.3%)., Conclusion: Of the analyzed isolates, 1,424 (89%) belonged to L. monocytogenes, showing a good quality in isolation and identification. Most of these isolates belonged to serotype 4b, 820 (57.6%), a highly virulent serotype. Obligatory surveillance of this microorganism is recommended.

Increase of bovine livestock rates in fragile areas of the Rolling Pampa entails a high risk of biological contamination. This biological contamination is regulated by edaphic variables such as texture, which control biological contaminants transport towards water bodies. In this work bacterial adsorption was correlated with individual particle sizes in 27 soils of a typical basin of the Rolling Pampa with slow centrifugation techniques. Bacterial adsorption values, using E. coli (ATCC 8739), ranged between 25.3 and 73.3% and significant correlation (R² = 0.6) was found between bacterial adsorption and clay content. This correlation was improved when particles smaller than 3 µm were considered (R² = 0.64) highlighting the capacity of very fine silt in adsorption mechanisms. Data obtained were compared with those proposed by Ling et al. (2002), finding similar slope but different intercept. This difference disappeared when a wild strain, isolated from bovine manures present in the basin, was used, since a bacterial adsorption increase of 48% was found.

Objectives: Quantify contamination by verotoxin-producing Escherichia coli associated with hemolytic uremic syndrome (VTEC-HUS) in cattle carcasses and generate estimates of exposure in three likely scenarios., Methods: A model was constructed of the frequency and magnitude of VTEC-HUS contamination from primary production to the removal of the carcasses from cold storage, based on the published scientific information, epidemiological data, and information from local experts. The probability distributions that best described each step in the process and scenarios were input to the @Risk program with multiple simulations using Monte Carlo analysis. Pearson s correlation test was used for the sensitivity analysis., Results: The estimated frequency of carcasses with VTEC-HUS was 0.37 (95% CI: 0.26 to 0.58) and the final load of VTEC-HUS was 0.47 log CFU/carcass (95% CI: -2.46 to 3.62). The most closely related variables were the fattening system (r = -0.681) and the theoretical concentration of VTEC-HUS on the cattle's skin (r = 0.702). Vaccinating the animals reduced the frequency of VTEC-HUS in the carcasses by 54.1%, although there were no significant changes in the final VTEC-HUS load. Washing the carcasses reduced the final load by 0.42 log CFU/carcass compared with the baseline model, without any change in the frequency. A 50%-60% increase in the percentage of animals fattened in pens would increase the frequency of carcasses contaminated with VTEC-HUS by 15%-23%., Conclusions: Vaccinating the animals was the most effective scenario for reducing introduction of the bacteria in the beef production chain. Intensifying livestock production will increase the public health risk due to greater exposure to VTEC-HUS.

Antimicrobial resistance profiles in indicator and zoonotic bacteria isolated from faeces of healthy animals without clinical signs of the following species: bovine, equine, ovine, porcine, layer hens, and canine, were studied. The chosen antimicrobials are frequently used in veterinary and human medicine. The agar diffusion was the method used. The obtained results of 240 Escherichia coli, 189 Enterococcus spp., 11 Campylobacter spp. and 2 Salmonella Gaminara (16:d:1,7) showed a greater percentage of resistance and multiresistance in intensive breeding animals, porcine and layer hens. The observed resistance to ampicillin, streptomycin, tetracycline and nalidixic acid in E. coli coincides with the antimicrobials most commonly used on animal farms, the same as tetracycline and erythromycin in Enterococcus spp. The strains of Salmonella Gaminara (16:d:1,7) were susceptible to the antimicrobials tested. In Campylobacter spp. the scarce number of isolates hindered an adequate interpretation of the results. Owing to the lack of data in our country on antimicrobial resistance in indicator and zoonotic bacteria in domestic animals, we consider that the obtained values could be used as a starting point for a future monitoring program.

We describe 3 outbreaks of brucellosis investigated by our Occupational Health Service in a 1-year period. Two of these outbreaks, with 2 cases each, occurred in 2 cheese factories and the third outbreak, also with 2 cases, occurred in a cattle laboratory belonging to the local government. In both cheese factories, numerous opportunities for the workers to become infected were found. The greatest risk was considered to be the area for unloading milk, while failure to use personal protection equipment by workers, deficiencies in the laboratories, and the lack of effective separation between areas were also potential risk factors. In the cattle laboratory, we found at least 13 major risk factors that could allow brucellosis transmission. In Spain, there is a substantial risk of Brucella infection in laboratories or dairy factories and current preventive measures are ineffective.

A quantitative risk assessment was developed for verocytotoxigenic Escherichia coli (VTEC) associated with hamburger consumption. The assessment (simulation model) considers the distribution, storage and consumption patterns of hamburgers. The prevalence and concentration of VTEC were modelled at various stages along the agri-food beef production system using input derived from Argentinean data, whenever possible. The model predicted an infection risk of 4.45 x 10(-4) per meal for adults. The risk values obtained for children were 2.6 x 10(-4), 1.38 x 10(-5) and 4.54 x 10(-7) for infection, Hemolytic Uremic Syndrome (HUS) and mortality, respectively. The risk of infection and HUS was positively correlated with bacterial concentration in meat (r = 0.664). There was a negative association between homemade hamburgers (r = -0.116) and the risk of illness; however this association has been considered due to differences between retail and domiciliary storage systems (r = -0.567) and not because of the intrinsic characteristics of the product. The most sensitive points of the production system were identified through the risk assessment, therefore, these can be utilized as a basis to apply different risk management policies in public health.

Typeability, reproducibility, and discriminatory power of ERIC-PCR and Apal-PFGE to establish the genetic relation of P. multocida strains were determined. Forty-nine strains of different source, biotype, capsular group, somatic serotype, and resistance to antimicrobials were studied. By ERIC-PCR, 31 patterns were defined with 10 to 14 bands in a rank of 0.2 and 1.2 kb. By Apal-PFGE, 37 restriction patterns were established with 7 to 15 bands of 34 to 450 kb. Typeability was 100% (T=1) for ERIC-PCR, and 94% (T = 0.94) for Apal-PFGE. Reproducibility of both techniques was 100% (R=1). Discriminatory power was 93% (D = 0.93) for ERIC-PCR, and 98% (D = 0.98) for Apal-PFGE. By using both techniques, epidemiologically related strains were grouped, and unrelated strains were clearly differentiated. The value of ERIC-PCR and Apal-PFGE as complements to epidemiologic studies was demonstrated, especially when both techniques were used to analyze the strains.

Background: Leptospirosis is a zoonotic disease and its incidence is known in Chile since 2002, when it was incorporated as a disease that must be reported to health authorities. A serologic survey for leptospirosis was performed in humans and animals from a farm in a semi urban area in Santiago Chile, after the death of a farmer due to Weil disease in that place., Aim: To report the prevalence of antibodies against leptospirosis and to determine exposure to infection risk factors in the humans and domestic animals studied in this survey., Material and Methods: Antibodies were detected by IgM immunodot and indirect haemagglutination test in 61 humans (43 male, aged 5 to 70 years) and by microscopic agglutination test (MAT) in 44 animals. A questionnaire was applied to determine their exposure to risk factors for infection with Leptospira., Results: Seventy two percent of the studied population were farm workers and 70% had activities that required contact with water from canals, 41% cleaned closed places where rodents were present. Other risk factors detected were lack of sewage and waste disposal, high level of rodent infestation and disposal of faeces into canals used for watering. Two humans (3.3%) and six animals (1 bovine and 5 rodents) had positive antibodies. Among animals, antibodies against Leptospira serovar pomona and icterohaemorragiae were detected., Conclusions: In Chile, leptospirosis exists not only in rural areas but semi urban ones close to Santiago, although the prevalence is low. Education is necessary among semi urban population to avoid infection.

Beta toxin of C. chauvoei has desoxiribonuclease (DNase) activity which is regarded as one of its virulence factors. The production of DNase was detected in strains isolated from bovines, using as controls C. chauvoei ATCC 10092, and C. perfringens Type A and C. septicum, both laboratory isolates. The enzyme activity was made evident on a DNA substrate observing the macroscopic degradation. A simple methodology was developed using a commercial medium for DNase test, with the incorporation of sterile horse serum. Each strain was streaked on the surface of the medium, incubated in anaerobic atmosphere at 37 degrees C for 48 hours. The plates were revealed with HCI 1 N. The appearance of a clear and transparent zone around and under the microbial growing was considered a positive reaction. Enzyme activity was detected in 10 of 12 strains and also in the controls. The serum addition to the commercial basal medium allows the optimum development of the microorganism showing the enzymatic digestion zone.

Many efforts have been done in order to identify species of Gram positive and catalase positive coccus isolated from raw milk. The aim of this epidemiological observation, was to identify different strains isolated from raw milk according to conventional criteria and to recommend a useful and practical methodology for their correct identification. Gram positive and catalase positive coccus were tested for bacitracin resistance, novobiocin susceptibility, coagulase and others tests (e.g. carbohydrate fermentation). Dichotomic keys were designed to typify Staphylococcus' species. They were grouped into: Group I, coagulase positive, novobiocin susceptibility; Group II coagulase negative novobyocin resistance; and Group III coagulase negative novobiocin susceptibility. 62 strains were tested and S. hycus (17.7%) was the most isolated species, S. aureus (14.5%), S. sciuri (12.9%) and S. haemolyticus (11.3%) were also isolated. S. epidermidis was not isolated.

The occurrence of Yersinia enterocolitica in tonsils and rectal swabs from 100 healthy pigs and the rectal swabs of 100 healthy cattle slaughtered at Santiago-Chile were analysed. Yersinia enterocolitica was isolated from 48 (48%) pigs but not from cattle. 98.2% of strains were of 4/O3 bioserogroup, considered to be pathogenic for humans. All of the strains were resistant to penicillin producing beta-lactamase. Most of them were resistant to neomicin and tetracycline. The pYV marker was used to demonstrate pathogenicity in all strains by four different assays: 65.5% of the strains were pYV positive by their plasmid profile; 73.3% by crystal violet binding; 84.5% by calcium dependency and 87.9% by hybridization with probe associated with cytotoxicity to Hep-2 cells in vitro. All of the Yersinia enterocolitica strains were pYV positive with at least one of the four tests analysed, 46/58 strains were positive by three tests simultaneously. The similarities between associated cytotoxic genes of porcine and human strains is discussed. The phenotypic and genotypic characteristics demonstrated by the isolates strains suggest that the pigs in Chile are reservoir of potential pathogenic Yersinia enterocolitica for humans.

Virulence factors such as hydrophobicity of cell surface, capsule formation and slime production were investigated in 393 CNS strains, 190 isolated from bovine mastitis and 203 from human infections; in addition a selected number of CNS species were experimentally infused into the teat cistern of lactating rabbits for pathogenicity tests. Most human (95%) and bovine (82.6%) strains showed cell hydrophobicity properties, however only 11.3% and 7.9% were capsulated strains, respectively. Slime production was detected in 10.5% of bovine strains but only in 0.9% of human strains. Using the lactating rabbit model it was shown that S. chromogenes, S. epidermidis, S. saprophyticus and S. haemolyticus were the most pathogenic species.

From January 1990 to July 1992 a prospective study on the salmonellosis form of presentation, reservoirs and transmission in Tandil was carried out. Forty strains of Salmonella enterica were isolated with the following distribution: 28 humans (17 children and 11 adults), 6 in foods (1 in raw milk, 3 in well water, 1 in home made mayonnaise and 1 in chicken salad) and 6 in animals (1 in cow, 2 in chicken and 2 in calves). Salmonella Enteritidis was the most frequent isolate. Disease was evident only in a few susceptible hosts and the epidemiological chain could not be determined in all the cases.

Evaluation of phagocytosis and bactericidal effect of Pasteurella haemolytica and P. multocida was conducted on bovine alveolar macrophages freshly obtained through bronchioalveolar washings from live animals. Cytotoxic activity of these bacteria on the alveolar macrophages was evaluated through the simple visual assay in microplates, using bovine blood leukocytes as a comparative target cell. In order to evaluate phagocytosis the following variables were considered P. haemolytica and P. multocida (independently) in contact with alveolar macrophages, P. haemolytica and P. multocida in suspension as a positive control of bacterial growth, and RPMI-1640 medium alone, as a negative control of bacterial growth. To measure bactericidal capacity, bacteria were incubated with plastic adhered alveolar macrophages at 30 minutes and 3 hours intervals. Samples incubated 30 minutes were taken as phagocytosis-base readings and at the 3 h interval to evaluate bactericidal capacity of the alveolar macrophages on phagocytized bacteria. Reading of the samples of each evaluation was conducted in a spectrophotometer a 380 nm. Phagocytosis results indicated that bacterial proliferation was higher when bacteria were alone as compared when they were with alveolar macrophages (p < 0.05). Bactericidal capacity of the macrophages was efficient because bacterial numbers were higher in the first evaluation as compared to the second (p < 0.05). It was demonstrated that the cytotoxic effect of P. haemolytica was more severe on blood leukocytes as compared to alveolar macrophages (p < 0.05). There was no evidence of P. multocida cytotoxicity on the evaluated cells. With the development of this technique for the obtention of alveolar macrophages and using spectrophotometry for the phagocytosis and bactericidal effect evaluations, numerous variables and samples can be tested, such as opsonized bacteria or to measure the behaviour of alveolar macrophages infected with different agents involved in the bovine pneumonic complex.

Growth of 3 reference bovine C. fetus strains in media with and without antibiotics and bacteriostats active against the most common contaminant bacteria in the bovine genital tract was evaluated. In addition, 2 regional bovine C. fetus strains and 1 reference C. sputorum biovar bubulus strain were used in some experiments. Reference strain C. fetus subsp. venerealis was completely inhibited by polymyxin (> or = 0.25 IU/ml) whereas the other C. fetus strains were not inhibited. In Shepler's medium supplemented with rifampicin (10 micrograms/ml) subsp. fetus, was the only one to grow. When rifampicin was used at 5 micrograms/ml together with a reduced dose of the other Shepler's antibiotics, especially polymyxin B (0.85 IU/ml), subsp. venerealis was able to grow; nevertheless even at such a reduced dose, rifampicin was inhibitory for the biotype intermedius. It was demonstrated that triclosan (Irgasan) could be very useful at < or = 10 micrograms/ml in media with added blood, < or = 6 micrograms/ml in brucella broth and < or = 3 micrograms/ml in Mueller-Hinton broth for isolation of all subspecies of C. fetus. The sensitivity of C. fetus to 5-fluorouracil was variable: subsp. fetus was resistant (up to 800 micrograms/ml) whereas subspp. venerealis and biotype intermedius grew slowly or sometimes did not grow at all in concentrations of 6.25 micrograms/ml onwards. Fosfomycin was inhibitory to all C. fetus strains at > or = 50 micrograms/ml. C. sputorum biovar. bubulus was less inhibited than C. fetus with triclosan grew up to more than 100 micrograms/ml, with 5-fluorouracil up to 100 micrograms/ml and with fosfomycin up to 50 micrograms/ml. Growth of C. fetus subspp. was compared in different microaerophilic atmospheres contained in anaerobic jars (Oxoid HP 11) without palladium catalyzer. Growth with nitrogen or hydrogen was similar. When jars were replaced by 15 x 13 cm cylindrical cans without valves or gas measurement devices only pure hydrogen supported satisfactory growth of all C. fetus subspp. and C. sputorum biovar. bubulus strains. The candle system, a commercial nitrogen rich gas mixture and pure carbonic anhydride prepared in these cans failed to enable these strains to grow. C. fetus subsp. fetus was more aero-tolerant than subsp. venerealis and its biotype intermedius and was able to grow, although very weakly, with only carbonic anhydride added to an aerobic atmosphere. The growth obtained using a commercial gas generating microaerophilic kit (Oxoid BR-56) was comparable to the one achieved with the hydrogen rich atmosphere prepared in our laboratory.

Brucellosis is an important and widely distributed zoonosis in Mexican cattle which also affects an unknown proportion of the human population. This report presents the brucellosis antibody levels registered in the National Seroepidemiology Survey (NAS) in sera obtained from 66,982 healthy persons from one to 98 years of age and determined by the test of plaque microagglutination. Seroprevalences by states ranged from 0.24 per cent in Morelos to 13.5 per cent in the state of Mexico. The national mean was estimated to be 3.42 per cent. The analysis showed no statistical differences for brucellosis antibody levels by urban and rural residence and by density of family sleeping areas (three or more persons vs. one or two persons per bedroom). Adults between 20 and 39 years of age had greater seropositivity and children from one to nine years had the least. Women were most affected and had 48 per cent more seropositivity than men. According to the information obtained in the study, brucellosis in Mexico has the following characteristics: it is related to gender but not to occupation; affects persons in all age groups, social strata and is independent of size of the community of residence. Historically, brucellosis has been an endemic disease in Mexico. Recently an increasing incidence has been reported, and this is possibly due to a better national notification system.

We report a case of milker's nodules in a male who was not a professional cattle raiser with indirect and accidental transmission by fomites. A parapoxvirus was demonstrated from cutaneous lesions by electron microscopy with negative stain.

Eleven Yersinia enterocolitica strains isolated from bovine tongues and classified as B1 0:5 Lis Xz (8), B2 0:9 Lis X3 (2), nontypable (1), were examined for the following virulence-associated characteristics: autoagglutination, calcium dependency, Sereny test, congo red binding and presence of 40-48 MDa plasmids. Heat-stable enterotoxin production was also determined. Antibiotic susceptibility was assayed according to the modified Bauer-Kirby's method. Two Y. enterocolitica B1 0:5 Lis Xz strains were positive for autoagglutination, calcium dependency and congo red binding; both exhibited nearly 40 MDa plasmids and one of them was enterotoxigenic. The other strains did not carry virulence-associated plasmids, 5 were congo red positive and 4 produced enterotoxin. Therefore, two B1 0:5 Lis Xz strains would be potentially virulent. All strains were susceptible to piperacillin, mezlocillin, cefuroxime, cefotaxime, amikacin, kanamycin, sisomicin, phosphomycin , chloramphenicol, trimethoprim-sulfamethoxazole and pipemidic acid. Ampicillin and sulfisoxazole proved to be less efficient.

In December 1979, an enzootic with a high rate mortality diarrhea in few days old calves, fed artificially, began on a rural farm, located in El Trébol (provincia de Santa Fe). Bacteriologic studies allowed the isolation of Escherichia coli from both blood and mesenteric lymph nodes. Symptoms were reproduced in two healthy calves injected with a toxin made from this bacteria. Autopsy of one of these calves revealed congestion and hemorrhagic disseminated in the intestinal mucus membrane together with infarcted mesenteric lymph nodes. This coli enterotoxicosis extended until March 1980, was the worst pathology affecting the farm during the last ten years (Tables 2, 3). The mortality from this enzootic increased six times as compared with four month period from 1970 to 1979, and it was doubled during January and March (Table 4). The predisposing factors that give rise to this illness and the bacterial etiology of which was demonstrated by experimental methods are discussed.

A search for Y. enterocolitica in fresh foods of animal origin has been carried out. Isolations were obtained from "chorizos" (thick fresh sausages), "salchichas" (slender fresh sausages), bovine and pig's tongues and caecum (Tables 1, 2). Enrichments were performed in saline phosphate buffer 0.067 M, pH 7.6 and nutrient broth with 0.5% glucose. Caecum and tongue samples were postenriched in 0.5% KOH. Subcultures were done in Salmonella-Shigella agar, MacConkey agar and eosin-methylene blue agar. Isolates were identified through biochemical, serological and lysotyping methods. The following biotypes (B), serotypes (O) and lysotypes (Lis) were isolated: from "chorizos", B2, 0:9, Lis X3 and B1, 0:7,8, Lis Xo. From "salchichas", B1, 0:5, Lis Xz. From bovine tongues, B1, 0:5, Lis Xz and B2, 0:9, Lis X3. From pig tongues, B1, 0:6, Lis Xz. From pig caecum, B1, 0:6, Lis Xz and B1, 0:5, Lis Xz. Serotype B2, 0:9, Lis X3 isolated from "chorizos" and bovine tongues has been only exceptionally found outside of human beings. Serotype B1, 0:6, Liz Xz was isolated from the tongue and caecum of one pig. From the caecum of another pig two serotypes, B1, 0:5, Liz Xz and B1, 0:6, Liz Xz, were isolated. In order to determine the importance of Y. entercolitica as etiologic agent of yersiniosis in Argentina, further studies on the frequency and distribution of this agent are recommended.