Origin of Contamination and Genetic Diversity of Escherichia coli in Beef Cattle

Abstract

The possible origin of beef contamination and genetic diversity of Escherichia coli populations in beef cattle, on carcasses and ground beef, was examined by using random amplification of polymorphic DNA (RAPD) and PCR-restriction fragment length polymorphism (PCR-RFLP) analysis of the fliC gene. E. coli was recovered from the feces of 10 beef cattle during pasture grazing and feedlot finishing and from hides, carcasses, and ground beef after slaughter. The 1,403 E. coli isolates (855 fecal, 320 hide, 153 carcass, and 75 ground beef) were grouped into 121 genetic subtypes by using the RAPD method. Some of the genetic subtypes in cattle feces were also recovered from hides, prechilled carcasses, chilled carcasses, and ground beef. E. coli genetic subtypes were shared among cattle at all sample times, but a number of transient types were unique to individual animals. The genetic diversity of the E. coli population changed over time within individual animals grazing on pasture and in the feedlot. Isolates from one animal (59 fecal, 30 hide, 19 carcass, and 12 ground beef) were characterized by the PCR-RFLP analysis of the fliC gene and were grouped into eight genotypes. There was good agreement between the results obtained with the RAPD and PCR-RFLP techniques. In conclusion, the E. coli contaminating meat can originate from cattle feces, and the E. coli population in beef cattle was highly diverse. Also, genetic subtypes can be shared among animals or can be unique to an animal, and they are constantly changing.

Temporal Dynamics and Impact of Manure Storage on Antibiotic Resistance Patterns and Population Structure of Escherichia coli Isolates from a Commercial Swine Farm

“…Results from this study suggest that rep-PCR fingerprints generated from a library constructed from a commercial swine manure storage facility would remain representative of the population structure over a period of at least several months. However, the frequency of resistance to specific antibiotics varied widely on a monthly basis, supporting previous findings that this temporal variability must be captured in the library construction (2,4,26,58). These findings are consistent with the chromosomal location and apparent stability of repeated sequences detected by PCR with the BOXA1R primer and with the frequent association of antibiotic resistance determinants with potentially unstable plasmids, integrons, and transposons (1,17,37,46,56).…”

“…On the other hand, observed populations of E. coli distinguished by repetitive extragenic palindromic PCR (rep-PCR) were found to be consistently more diverse in stored manure slurry than in freshly shed feces from the corresponding swine (32). Changes in the distribution of attributes among populations of E. coli that are used to distinguish host source (e.g., antibiotic resistance and dominant host-specific genotypes detected by ribotyping, pulsed-field gel electrophoresis, or rep-PCR methods) could influence the ability of library-dependent microbial source tracking methods to correctly identify the porcine host (2,4,20,26,27,35,36,38,42,50,54).…”

Prevalence of Escherichia coli O157 in Saskatchewan Cattle: Characterization of Isolates by Using Random Amplified Polymorphic DNA PCR, Antibiotic Resistance Profiles, and Pathogenicity Determinants

“…In preliminary experiments, the following four decamer primers were tested against a panel of 15 different E. coli O157 isolates for the random amplification of polymorphic DNA: GEN 15001 (5Ј-G TGCAATGAG-3Ј) (39), 1283 (5Ј-GCGATCCCCA-3Ј) (15), 1290 (5Ј-GTGGA TGCGA-3Ј) (34), and 1254 (5Ј-CCGCAGCCAA-3Ј) (1,2,27). Primer 1283 provided the greatest discriminatory ability among the E. coli O157 test isolates and was therefore used in this study.…”

Characterization of Escherichia coli and other Enterobacteriaceae in producer-distributor bulk milk

“…Some of the isolates from certain provinces were found in all the cluster groups which indicates high genetic diversity among the isolates and wide distribution despite spatial differences in the milk sources. High genetic diversity of E. coli has been noted in isolates from human, animal, food and the environment (Aslam et al, 2003, Apun et al, 2006, Van Elsas et al, 2011. Reason for high genetic diversity in the E. coli could be attributed to its versatility and high degree of genomic plasticity, via gene loss or gain and through lateral gene transfer (Rasko et al, 2008).…”