Category Archives: Enterobacteriaceae

PubMed

The family Enterobacteriaceae has undergone significant morphogenetic changes in its more than 85-year history, particularly during the past 2 decades (2000 to 2020). The development and introduction of new and novel molecular methods coupled with innovative laboratory techniques have led to many advances. We now know that the global range of enterobacteria is much more expansive than previously recognized, as they play important roles in the environment in vegetative processes and through widespread environmental distribution through insect vectors. In humans, many new species have been described, some associated with specific disease processes. Some established species are now observed in new infectious disease settings and syndromes. The results of molecular taxonomic and phylogenetics studies suggest that the current family Enterobacteriaceae should possibly be divided into seven or more separate families. The logarithmic explosion in the number of enterobacterial species described brings into question the relevancy, need, and mechanisms to potentially identify these taxa. This review covers the progression, transformation, and morphogenesis of the family from the seminal Centers for Disease Control and Prevention publication (J. J. Farmer III, B. R. Davis, F. W. Hickman-Brenner, A. McWhorter, et al., J Clin Microbiol 21:46-76, 1985, https://doi.org/10.1128/JCM.21.1.46-76.1985) to the present.

Journal of Food Protection

In this study, the distribution of hygienic indicator bacteria in cattle livers and bile was examined at slaughterhouses. First, 127 cattle livers with gallbladders were carefully eviscerated from the carcasses at 10 slaughterhouses. Microbiological examination showed that 9 bile (7.1%) and 19 liver parenchyma (15.0%) samples were positive for the family Enterobacteriaceae (EB) with means ± SD of 3.68 ± 4.63 log CFU/mL and 1.59 ± 2.47 log CFU/g, respectively; thus, bacterial contamination was apparent even at the postevisceration stage. Subsequently, 70 cattle livers were obtained at the postprocessing/storage stage from 7 of the ten slaughterhouses; microbiological analysis revealed greater means of EB in the liver parenchyma (means ± SD of 3.00 ± 3.89 log CFU/g, P =0.011) than those at postevisceration stage, suggesting that bacterial dissemination and/or replication occurred in the liver parenchyma during processing and storage. According to 16S rRNA ion semiconductor sequencing analysis of representative samples from 12 cattle, Proteobacteria , Firmicutes , and Actinobacteria were dominant in both the parenchyma and bile, in which EB/ Escherichia coli were predominate among EB-rich livers. These results suggest that bile plays a role as a vehicle for bacterial transmission to the liver parenchyma. This is the first study to demonstrate bacterial distribution and community structure in the liver and biliary microecosystem of cattle at slaughter. Our data provide possible implication of EB testing in bile to screen cattle livers contaminated with high levels of fecal indicator bacteria.