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The purpose of this study was to identify relationships between spoligotypes of M. bovis from cattle in Mexico and those reported in countries with free trade of cattle with Mexico: Australia, Canada, New Zealand and the United States of America. Mexican spoligotypes were obtained from isolates collected from cattle in different parts of the country. Spoligotypes from Canada and New Zealand were obtained from different reports in the literature. Those from the United States were obtained from the database of the National Veterinary Services Laboratory in APHIS-USDA. In order to perform the analysis in a single data set, spoligotypes were all converted to binary data and classified according to or . Epidemiologic information included country and species infected. From 3,198 isolates, 174 different spoligotypes were obtained, 95 were orphans. Ninety one percent of the isolates came from the Unites States (n = 1,609) and Mexico (n = 1,323). Spoligotype SB0265 is shared between Canada and the United States in cattle and wildlife. Six spoligotypes, SB0673, SB0121, SB0145, SB0971, SB0140 and SB1165, were frequent in cattle and wildlife in the United States and cattle in Mexico, suggesting wide exchange of strains. Spoligotype SB0669 was found only in Mexico. Spoligotype SB0140 was the most common in Australia and the sixth in the United States and Mexico. In a phylogenetic analysis, spoligotype SB0140 appears as the oldest spoligotype in the data set, suggesting this as the ancestral spoligotype for all spoligotypes in the five countries. Some spoligotypes are shared by animals and humans, corroborating the zoonotic importance of M. bovis. [ABSTRACT FROM AUTHOR]

The molecular fingerprints of 878 isolates of Mycobacterium bovis from cattle, mostly dairy cattle, collected from cattle between 2009 and 2010 in different regions of Mexico were obtained by spoligotyping. Seventy-two percent (72 %) of the spoligotypes fell into nine clusters, and 27 % of the isolates fell into only two spoligotypes; 149 were orphan spoligotypes. The two predominant spoligotypes, arbitrarily designated as SP1 and SP2, were found in almost all States in Mexico, especially in central Mexico, where a concentration of dairy cattle is known. In spite of the wide distribution of spoligotypes observed, some show high regional preference, especially those in geographically distant regions. Only a few spoligotypes show patterns completely different from those shown by the most frequent spoligotypes, suggesting strange sources of infection or the formation of new genetic lines derived from non-lethal mutations. Most States with predominantly high dairy cattle populations showed similar spoligotypes, suggesting exchange of animals between regions. Some spoligotypes are common to dairy and beef cattle, suggesting transmission between populations, most probably due to the movement of dairy cattle to non-dairy regions. [ABSTRACT FROM AUTHOR]

Se obtuvieron patrones moleculares (espoligotipos) de 878 aislados de Mycobacterium bovis de ganado de diferentes regiones de México entre los años 2009 y 2010. Setenta y dos por ciento (72 %) de los espoligotipos cayeron en nueve grupos y 27 % de los aislados dentro de sólo dos espoligotipos; 149 fueron espoligotipos individuales. Los dos espoligotipos predominantes, arbitrariamente identificados como SP1 y SP2, se distribuyen en la mayor parte del territorio nacional, en especial en la zona centro de México en ganado especializado en producción de leche. A pesar de la amplia distribución geográfica de los espoligotipos de mayor frecuencia, algunos muestran cierta localización, en especial los encontrados en zonas geográficas distantes, como es el caso de Chihuahua y Baja California. Aunque pocos, algunos espoligotipos muestran patrones moleculares distintos a los mostrados por los espoligotipos de mayor frecuencia, sugiriendo fuentes de infección desconocida. La mayoría de los Estados con ganadería predominantemente lechera muestran espoligotipos comunes, lo que sugiere intercambio regional frecuente de ganado. Algunos espoligotipos son comunes en ganado para leche y ganado para carne, lo que sugiere transmisión entre estas dos poblaciones; se desconoce, sin embargo, si los animales de carne infectados provienen de explotaciones extensivas o si son de engordas ubicadas dentro de la explotación lechera. Se propone la tipificación rutinaria de aislados de M. bovis obtenidos en todos los laboratorios de diagnóstico y mejorar la captura de información epidemiológica de los casos, para hacer mejores conclusiones epidemiológicas de la distribución espacial de las cepas de este agente en el territorio nacional. [ABSTRACT FROM AUTHOR]

Food-borne bacterial infections have worldwide importance, and a great variety of antibiotic resistance mechanisms, mainly of the chromosome type, have rapidly developed. Antimicrobial resistance was determined in this study in terms of the presence of extended-spectrum β-lactamases (ESBLs), plasmid AmpC β-lactamases (pAmpC), and plasmid-mediated quinolone resistance (PMQR) from 155 Escherichia coli isolates obtained from bovine carcasses from two states in Mexico (states of Mexico and Jalisco). Isolates were challenged with β-lactam antimicrobials (ampicillin, ceftazidime, and cefotaxime) and quinolones (nalidixic acid and ciprofloxacin). The presence of the bla TEM, bla SHV, bla CTX-M, bla OXA , bla CMY, bla MOX, bla LAT, bla BIL, qnrA, qnrB, qnrS, aac(6')-Ib-cr, and qepA genes was examined by PCR. Clonal relationship was determined using pulsed-field gel electrophoresis (PFGE). The highest resistance was found to be to nalidixic acid (64 %), followed by ampicillin (32 %), ciprofloxacin (10 %), and ceftazidime and cefotaxime (both 1.3 %). bla CMY (n = 1), bla TEM (n = 24), qnrB (n = 9), and qnrS (n = 7) genes were detected. PFGE analysis showed that the majority of isolates had a different genotypic profile. To our knowledge, this is the first report of the presence of the qnrB, qnrS, and bla CMY genes in E. coli isolated from bovine meat in Mexico.

Meat of bovine origin is one of the major vehicles in the transmission of verotoxigenic Escherichia coli (VTEC) to human consumers. This pathogen can produce serious human illness, including bloody diarrhea and hemolytic uremic syndrome. The aim of the current study was to characterize E. coli isolates (mainly VTEC strains) belonging to several serotypes in samples from cattle carcasses and feces of three municipal slaughter plants from Mexico State. The genetic diversity and molecular relatedness among the isolates was evaluated with multiple-locus variable-number tandem repeat analysis (MLVA). To our knowledge, and with the exception of E. coli O157:H7, this is the first time that serotypes analyzed here have been subtyped by MLVA in Mexico. MLVA typing grouped the 37 strains from this study into 30 distinct genotypes, 26 of which were unique. These findings indicate that cattle carcasses and feces from slaughter plants in Mexico are a source of VTEC that are genetically diverse in terms of serotypes and virulence profiles. The presence of these pathogens in carcasses indicates the high probability of the spread of VTEC strains during slaughter and processing.

To determine the prevalence of Salmonella and Escherichia coli O157:H7 in cattle feedlots and the impact of subsequent contamination on carcasses in a Mexican Federal Inspection Type Standards harvest facility, 250 animals were tagged and sampled in each step of the slaughter process. Samples were taken from hides and fecal grabs, and composite samples were taken from three anatomical carcass sites (hindshank, foreshank, and inside round) during the slaughter process, at preevisceration (PE), prior to entering the hot box (PHB), and after 24 h of dry chilling (DC). Additionally, 250 fecal samples were collected from the feedlot (FL), holding pens (HP), and intestinal feces (IF), and water samples were taken from the HP area. E. coli O157:H7 and Salmonella detection were carried out with the BAX System, immunomagnetic separation, and conventional methods. Overall Salmonella prevalence was 52.5%. The highest prevalence (92.4%) was found on hides, followed by feces from the HP (91.0%), FL (55.56%), PE (49.0%), IF (46.8%), and PHB (24.8%), for all sampling periods combined. The lowest prevalence of 6.0% was found after DC. The overall prevalence of E. coli O157:H7 was as follows: 11.7% for hides, 5.2% for IF, 2.7% for FL, 2.0% for HP, 0.8% for PE, 0.4% for PHB, and 0.4% for the cooler. High prevalence of Salmonella in IF and on hides present a significant risk factor for contamination by Salmonella at the different processing steps. These results serve as a warning as to the risks of contamination in meats for these pathogens and the importance of following good manufacturing practices during beef production processes.

Spoligotyping is the most frequently used method for genotyping isolates of Mycobacterium bovis worldwide. In the current work, we compared spoligotypes from 1684 M. bovis isolates from Argentina (816), Brazil (412), Chile (66), Mexico (274) and Venezuela (116), obtained from cattle, humans, pigs, wild boars, farmed deer, goats, buffaloes, cats, and wild animals. A total of 269 different spoligotypes were found: 142 (8.4%) isolates presented orphan spoligotypes, whereas 1542 (91.6%) formed 113 different clusters. In cattle, SB0140 was the most representative spoligotype with 355 (24.6%) isolates, followed by SB0121 with 149 (10.3%) isolates. Clustering of spoligotypes ranged from 95.2% in Argentina to 85.3% in Mexico. Orphan spoligotypes were also variable, ranging from 23.7% in Mexico to 4.1% in Brazil. A large proportion of spoligotypes were common to the neighboring countries Argentina, Brazil and Chile. In conclusion, despite the diversity of spoligotypes found in the five countries studied, there are major patterns that predominate in these neighboring countries. These clusters may reflect a long-lasting active transmission of bovine tuberculosis or common historical origins of infection., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

The prevalence and antimicrobial resistance of Salmonella serotypes on beef carcasses from four small abattoirs in Jalisco State, Mexico, were investigated during a 10-month period. Following U.S. Department of Agriculture Food Safety and Inspection Service protocols, Salmonella was isolated from 78 (15.4%) beef carcasses (n = 505) after the final carcass water wash. Isolation frequency differed by establishment (P < 0.05) and was higher (P < 0.05) during the wet season (May through September) for all establishments. Thirteen Salmonella serotypes and four serogroups (partially serotyped isolates) were identified. The most prevalent were Salmonella enterica Give (24.4%), Salmonella Typhimurium (17.9%), and Salmonella Group B (14.1%). Antimicrobial susceptibility was tested against 11 drugs, and results indicated that 46.2% of the isolates were resistant to tetracycline, 42.3% were resistant to streptomycin, 23.1% were resistant to chloramphenicol, 21.8% were resistant to trimethoprim-sulfamethoxazole, and 19.2% were resistant to gentamicin. No resistance to ceftriaxone or ciprofloxacin was observed, and 33% of the isolates were resistant to three or more antimicrobials. Although Salmonella Give was the most prevalent serotype, 95% of the isolates of this serotype were susceptible to all antimicrobials tested. Antimicrobial resistance was more common in Salmonella Typhimurium, and 93% (13 of 14) of the isolates of this serotype were resistant to at least five antimicrobials. The frequency of multidrug-resistant Salmonella isolates differed among establishments (P < 0.05) and may be related to the origin of the cattle presented for harvesting. These findings highlight the need for control measures to reduce Salmonella prevalence on beef carcasses in small abattoirs in Mexico and for strategies to ensure the cautious use of antimicrobials in animal production to prevent and control the spread of antimicrobial-resistant foodborne pathogens.

We have tested the hypothesis that coarse-scale environmental features are associated with spatial variation in bovine tuberculosis (BTB) prevalence, based on extensive sampling and testing of cattle in the state of Jalisco, Mexico. Ecological niche models were developed to summarize relationships between BTB occurrences and aspects of climate, topography and surface. Model predictions, however, reflected the distributions of dairy cattle versus beef cattle, and the non-random nature of sampling any cattle, but did not succeed in detecting environmental correlates at spatial resolutions of 1 km. Given that the tests employed seek any predictivity better than random expectations, making the finding of no environmental associations conservative, we conclude that BTB prevalence is independent of coarsescale environmental features.

We report a retrospective analysis of 1933 Brucella strains isolated from humans and animals in Latin American countries between 1968 and 1991 and in Argentina between 1994 and 2006. During the first period 50% of strains were from humans, mainly from Argentina, Mexico and Peru but, while B. suis was the main cause of infection in Argentina, B. melitensis was responsible for most infections in the other countries. In Argentina in the later years, B. melitensis and B. suis were observed more frequently than in the first period while isolation of B. abortus decreased. Of 145 B. melitensis human isolates, eight gave susceptibility patterns to dyes and penicillin and two were B. melitensis biovar 3, which has never been reported in animals. Forty-six percent of B. suis isolated were resistant to dyes which is an atypical feature in this species.

The contamination of beef carcasses with Shiga toxin-producing O157:H7 and non-O157 Escherichia coli (STEC) obtained from a slaughter plant in Guadalajara, Mexico was investigated. A total of 258 beef carcasses were sampled during a 12-month period. All samples were assayed for STEC by selective enrichment in modified tryptone soy broth supplemented with cefixime, cefsulodin and vancomycin, followed by plating on Sorbitol MacConkey Agar supplemented with cefixime and tellurite (CT-SMAC). Simultaneously, all samples were assayed by immunomagnetic separation (IMS) and plated on CT-SMAC and CHROMagar. The presence of the stx1, stx2, eaeA and hly933 genes, recognized as major virulence factors of STEC, was tested for O157:H7 and non-O157 E. coli isolates by multiplex polymerase chain reaction (PCR). STEC was detected in two (0.8%) samples. One of these STEC isolates corresponded to the serotype O157:H7 showing stx2, eaeA and hyl933 genes. The other isolate corresponded to non-O157 STEC and only had the stx1 gene. Thirteen carcasses (5%) were positive for nonmotile E. coli O157 and 7 (2.7%) were positive for E. coli O157:H7. The presence of O157:H7 and non-O157 STEC on beef carcasses in this slaughter plant in Guadalajara, Mexico, emphasizes the importance of implementing the Hazard Analysis and Critical Control Point (HACCP) system, as well as the need for implementing, evaluating, and validating antimicrobial interventions to reduce the presence of potential pathogenic microorganisms.

The objectives of the present work were to detect Leptospira seropositive animals. The ELISA results report only IgG antibodies, which could be attributable to chronic infections or else, that they are healthy carriers. All polymerase chain reaction positive animals should be considered potential sources of infection.

A total of 13,000 pairs of lungs were examined at Mexico's City abbatoir, where 8,000 corresponded to sheep and 5,000 to cattle. From those, 224 pneumonic lesions were observed, obtaining 97 positive isolates, which yielded 112 strains of Pasteurella sp. Forty isolates were identified as P. haemolytica and 72 as P. multocida. One-hundred percent of P. haemolytica belonged to biotype A. Serotypes were determined by indirect haemagglutination. P. multocida isolates were classified according to the acriflavine and hyaluronidase techniques, 61% belonged to type A, 25% to type D and 14% were untypified. Somatic serotypes were determined by gel immunodiffusion; serotype 3 was more frequent, in sheep 72% and in cattle 77%.

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.