Gram-positive pathogens are causing many serious infections that affect humans and result in mild to severe diseases worldwide. In order to survive and initiate infection, enteric pathogens must resist the physiochemical defence factors in the human intestinal tract. One of these defence factors is bile, a potent antibacterial like compound in the intestine. Efflux pumps are the important mechanism by which bacteria resist antibacterial agents such as bile. Efflux of antimicrobial substances outside the bacterial cell is considered as a key factor for intestinal colonization and virulence of enteric pathogens. This paper will review the research conducted on efflux–mediated bile resistance in Staphylococcus aureus, Listeria monocytogenes, Enterococcus faecalis and Clostridium perfringens. These bacteria colonize in the human & animal gastrointestinal tract and they have a multiple mechanism to resist the innate defences in the gut and antibacterial activity of bile. However, bile resistance in these bacteria is not fully understood. The evidence from this review suggests that Gram-positive pathogens have the ability to active transport of bile. Further research is needed to know how these pathogens sense bile and how bile regulates its virulence factor. In general, therefore, it seems that understanding the specific mechanism of bile resistance in enteric bacteria including gram-positive pathogens may involve in the development of novel strategies to control and treatment of gastrointestinal infections.

Background and Objectives: Anaplasmosis is a zoonotic disease caused by Gram- negative bacterium from Anaplasmata- ceae family. Anaplasma causes high economic losses worldwide. 16S rRNA analysis was used to diagnose Anaplasma platys in Cattle. Phylogenetic tree and estimation of evolutionary divergence between A. platys isolates were performed. Materials and Methods: A total of 60 blood samples were collected from a cattle farm in AL- Diwaniyah province. 16S rRNA gene was identified using nested PCR. Overall, 40% of cattle that were chosen to collect the blood were identified to be infected with A. platys. Results: The results have shown presence of targeting partial region of 16S rRNA gene in 24 samples out of 60. Sequenc- ing results of 10 samples have revealed that the phylogenetic tree was divided in to two separate clades. Five isolates of A. platys- Iraq (accession no. OP646782, OP646783, OP646784, OP646790, and OP646791) were located in one clade with the A. platys- China (accession no. MN193068.1). While, five isolates (accession no. OP646785, OP646786, OP646787, OP646788, OP646789) were in different clade with two isolates of A. platys- Africa and A. platys- Zambia in distinct branch- es, close to the Rickettsiales. Conclusion: The phylogenetic study of A. platys sequences indicated that the isolates were collected from a cattle farm in Al- Dewaniyah were similar and close related to A. platys- China, A. platys- Zambia and A. platys- Africa). This study suggests that cattle can be considered a reservoir of A. platys.

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